1 /* 2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "compiler/disassembler.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "logging/log.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_linux.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "prims/jniFastGetField.hpp" 42 #include "prims/jvm.h" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/atomic.hpp" 46 #include "runtime/extendedPC.hpp" 47 #include "runtime/globals.hpp" 48 #include "runtime/interfaceSupport.hpp" 49 #include "runtime/init.hpp" 50 #include "runtime/java.hpp" 51 #include "runtime/javaCalls.hpp" 52 #include "runtime/mutexLocker.hpp" 53 #include "runtime/objectMonitor.hpp" 54 #include "runtime/orderAccess.inline.hpp" 55 #include "runtime/osThread.hpp" 56 #include "runtime/perfMemory.hpp" 57 #include "runtime/sharedRuntime.hpp" 58 #include "runtime/statSampler.hpp" 59 #include "runtime/stubRoutines.hpp" 60 #include "runtime/thread.inline.hpp" 61 #include "runtime/threadCritical.hpp" 62 #include "runtime/timer.hpp" 63 #include "semaphore_posix.hpp" 64 #include "services/attachListener.hpp" 65 #include "services/memTracker.hpp" 66 #include "services/runtimeService.hpp" 67 #include "utilities/decoder.hpp" 68 #include "utilities/defaultStream.hpp" 69 #include "utilities/events.hpp" 70 #include "utilities/elfFile.hpp" 71 #include "utilities/growableArray.hpp" 72 #include "utilities/macros.hpp" 73 #include "utilities/vmError.hpp" 74 75 // put OS-includes here 76 # include <sys/types.h> 77 # include <sys/mman.h> 78 # include <sys/stat.h> 79 # include <sys/select.h> 80 # include <pthread.h> 81 # include <signal.h> 82 # include <errno.h> 83 # include <dlfcn.h> 84 # include <stdio.h> 85 # include <unistd.h> 86 # include <sys/resource.h> 87 # include <pthread.h> 88 # include <sys/stat.h> 89 # include <sys/time.h> 90 # include <sys/times.h> 91 # include <sys/utsname.h> 92 # include <sys/socket.h> 93 # include <sys/wait.h> 94 # include <pwd.h> 95 # include <poll.h> 96 # include <semaphore.h> 97 # include <fcntl.h> 98 # include <string.h> 99 # include <syscall.h> 100 # include <sys/sysinfo.h> 101 # include <gnu/libc-version.h> 102 # include <sys/ipc.h> 103 # include <sys/shm.h> 104 # include <link.h> 105 # include <stdint.h> 106 # include <inttypes.h> 107 # include <sys/ioctl.h> 108 109 #ifndef _GNU_SOURCE 110 #define _GNU_SOURCE 111 #include <sched.h> 112 #undef _GNU_SOURCE 113 #else 114 #include <sched.h> 115 #endif 116 117 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 118 // getrusage() is prepared to handle the associated failure. 119 #ifndef RUSAGE_THREAD 120 #define RUSAGE_THREAD (1) /* only the calling thread */ 121 #endif 122 123 #define MAX_PATH (2 * K) 124 125 #define MAX_SECS 100000000 126 127 // for timer info max values which include all bits 128 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 129 130 #define LARGEPAGES_BIT (1 << 6) 131 //////////////////////////////////////////////////////////////////////////////// 132 // global variables 133 julong os::Linux::_physical_memory = 0; 134 135 address os::Linux::_initial_thread_stack_bottom = NULL; 136 uintptr_t os::Linux::_initial_thread_stack_size = 0; 137 138 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 139 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 140 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 141 Mutex* os::Linux::_createThread_lock = NULL; 142 pthread_t os::Linux::_main_thread; 143 int os::Linux::_page_size = -1; 144 bool os::Linux::_supports_fast_thread_cpu_time = false; 145 uint32_t os::Linux::_os_version = 0; 146 const char * os::Linux::_glibc_version = NULL; 147 const char * os::Linux::_libpthread_version = NULL; 148 pthread_condattr_t os::Linux::_condattr[1]; 149 150 static jlong initial_time_count=0; 151 152 static int clock_tics_per_sec = 100; 153 154 // For diagnostics to print a message once. see run_periodic_checks 155 static sigset_t check_signal_done; 156 static bool check_signals = true; 157 158 // Signal number used to suspend/resume a thread 159 160 // do not use any signal number less than SIGSEGV, see 4355769 161 static int SR_signum = SIGUSR2; 162 sigset_t SR_sigset; 163 164 // Declarations 165 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 166 167 // utility functions 168 169 static int SR_initialize(); 170 171 julong os::available_memory() { 172 return Linux::available_memory(); 173 } 174 175 julong os::Linux::available_memory() { 176 // values in struct sysinfo are "unsigned long" 177 struct sysinfo si; 178 sysinfo(&si); 179 180 return (julong)si.freeram * si.mem_unit; 181 } 182 183 julong os::physical_memory() { 184 return Linux::physical_memory(); 185 } 186 187 // Return true if user is running as root. 188 189 bool os::have_special_privileges() { 190 static bool init = false; 191 static bool privileges = false; 192 if (!init) { 193 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 194 init = true; 195 } 196 return privileges; 197 } 198 199 200 #ifndef SYS_gettid 201 // i386: 224, ia64: 1105, amd64: 186, sparc 143 202 #ifdef __ia64__ 203 #define SYS_gettid 1105 204 #else 205 #ifdef __i386__ 206 #define SYS_gettid 224 207 #else 208 #ifdef __amd64__ 209 #define SYS_gettid 186 210 #else 211 #ifdef __sparc__ 212 #define SYS_gettid 143 213 #else 214 #error define gettid for the arch 215 #endif 216 #endif 217 #endif 218 #endif 219 #endif 220 221 // Cpu architecture string 222 static char cpu_arch[] = HOTSPOT_LIB_ARCH; 223 224 225 // pid_t gettid() 226 // 227 // Returns the kernel thread id of the currently running thread. Kernel 228 // thread id is used to access /proc. 229 pid_t os::Linux::gettid() { 230 int rslt = syscall(SYS_gettid); 231 assert(rslt != -1, "must be."); // old linuxthreads implementation? 232 return (pid_t)rslt; 233 } 234 235 // Most versions of linux have a bug where the number of processors are 236 // determined by looking at the /proc file system. In a chroot environment, 237 // the system call returns 1. This causes the VM to act as if it is 238 // a single processor and elide locking (see is_MP() call). 239 static bool unsafe_chroot_detected = false; 240 static const char *unstable_chroot_error = "/proc file system not found.\n" 241 "Java may be unstable running multithreaded in a chroot " 242 "environment on Linux when /proc filesystem is not mounted."; 243 244 void os::Linux::initialize_system_info() { 245 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 246 if (processor_count() == 1) { 247 pid_t pid = os::Linux::gettid(); 248 char fname[32]; 249 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 250 FILE *fp = fopen(fname, "r"); 251 if (fp == NULL) { 252 unsafe_chroot_detected = true; 253 } else { 254 fclose(fp); 255 } 256 } 257 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 258 assert(processor_count() > 0, "linux error"); 259 } 260 261 void os::init_system_properties_values() { 262 // The next steps are taken in the product version: 263 // 264 // Obtain the JAVA_HOME value from the location of libjvm.so. 265 // This library should be located at: 266 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 267 // 268 // If "/jre/lib/" appears at the right place in the path, then we 269 // assume libjvm.so is installed in a JDK and we use this path. 270 // 271 // Otherwise exit with message: "Could not create the Java virtual machine." 272 // 273 // The following extra steps are taken in the debugging version: 274 // 275 // If "/jre/lib/" does NOT appear at the right place in the path 276 // instead of exit check for $JAVA_HOME environment variable. 277 // 278 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 279 // then we append a fake suffix "hotspot/libjvm.so" to this path so 280 // it looks like libjvm.so is installed there 281 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 282 // 283 // Otherwise exit. 284 // 285 // Important note: if the location of libjvm.so changes this 286 // code needs to be changed accordingly. 287 288 // See ld(1): 289 // The linker uses the following search paths to locate required 290 // shared libraries: 291 // 1: ... 292 // ... 293 // 7: The default directories, normally /lib and /usr/lib. 294 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 295 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 296 #else 297 #define DEFAULT_LIBPATH "/lib:/usr/lib" 298 #endif 299 300 // Base path of extensions installed on the system. 301 #define SYS_EXT_DIR "/usr/java/packages" 302 #define EXTENSIONS_DIR "/lib/ext" 303 304 // Buffer that fits several sprintfs. 305 // Note that the space for the colon and the trailing null are provided 306 // by the nulls included by the sizeof operator. 307 const size_t bufsize = 308 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 309 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 310 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 311 312 // sysclasspath, java_home, dll_dir 313 { 314 char *pslash; 315 os::jvm_path(buf, bufsize); 316 317 // Found the full path to libjvm.so. 318 // Now cut the path to <java_home>/jre if we can. 319 pslash = strrchr(buf, '/'); 320 if (pslash != NULL) { 321 *pslash = '\0'; // Get rid of /libjvm.so. 322 } 323 pslash = strrchr(buf, '/'); 324 if (pslash != NULL) { 325 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 326 } 327 Arguments::set_dll_dir(buf); 328 329 if (pslash != NULL) { 330 pslash = strrchr(buf, '/'); 331 if (pslash != NULL) { 332 *pslash = '\0'; // Get rid of /<arch>. 333 pslash = strrchr(buf, '/'); 334 if (pslash != NULL) { 335 *pslash = '\0'; // Get rid of /lib. 336 } 337 } 338 } 339 Arguments::set_java_home(buf); 340 set_boot_path('/', ':'); 341 } 342 343 // Where to look for native libraries. 344 // 345 // Note: Due to a legacy implementation, most of the library path 346 // is set in the launcher. This was to accomodate linking restrictions 347 // on legacy Linux implementations (which are no longer supported). 348 // Eventually, all the library path setting will be done here. 349 // 350 // However, to prevent the proliferation of improperly built native 351 // libraries, the new path component /usr/java/packages is added here. 352 // Eventually, all the library path setting will be done here. 353 { 354 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 355 // should always exist (until the legacy problem cited above is 356 // addressed). 357 const char *v = ::getenv("LD_LIBRARY_PATH"); 358 const char *v_colon = ":"; 359 if (v == NULL) { v = ""; v_colon = ""; } 360 // That's +1 for the colon and +1 for the trailing '\0'. 361 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 362 strlen(v) + 1 + 363 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 364 mtInternal); 365 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 366 Arguments::set_library_path(ld_library_path); 367 FREE_C_HEAP_ARRAY(char, ld_library_path); 368 } 369 370 // Extensions directories. 371 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 372 Arguments::set_ext_dirs(buf); 373 374 FREE_C_HEAP_ARRAY(char, buf); 375 376 #undef DEFAULT_LIBPATH 377 #undef SYS_EXT_DIR 378 #undef EXTENSIONS_DIR 379 } 380 381 //////////////////////////////////////////////////////////////////////////////// 382 // breakpoint support 383 384 void os::breakpoint() { 385 BREAKPOINT; 386 } 387 388 extern "C" void breakpoint() { 389 // use debugger to set breakpoint here 390 } 391 392 //////////////////////////////////////////////////////////////////////////////// 393 // signal support 394 395 debug_only(static bool signal_sets_initialized = false); 396 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 397 398 bool os::Linux::is_sig_ignored(int sig) { 399 struct sigaction oact; 400 sigaction(sig, (struct sigaction*)NULL, &oact); 401 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 402 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 403 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 404 return true; 405 } else { 406 return false; 407 } 408 } 409 410 void os::Linux::signal_sets_init() { 411 // Should also have an assertion stating we are still single-threaded. 412 assert(!signal_sets_initialized, "Already initialized"); 413 // Fill in signals that are necessarily unblocked for all threads in 414 // the VM. Currently, we unblock the following signals: 415 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 416 // by -Xrs (=ReduceSignalUsage)); 417 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 418 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 419 // the dispositions or masks wrt these signals. 420 // Programs embedding the VM that want to use the above signals for their 421 // own purposes must, at this time, use the "-Xrs" option to prevent 422 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 423 // (See bug 4345157, and other related bugs). 424 // In reality, though, unblocking these signals is really a nop, since 425 // these signals are not blocked by default. 426 sigemptyset(&unblocked_sigs); 427 sigemptyset(&allowdebug_blocked_sigs); 428 sigaddset(&unblocked_sigs, SIGILL); 429 sigaddset(&unblocked_sigs, SIGSEGV); 430 sigaddset(&unblocked_sigs, SIGBUS); 431 sigaddset(&unblocked_sigs, SIGFPE); 432 #if defined(PPC64) 433 sigaddset(&unblocked_sigs, SIGTRAP); 434 #endif 435 sigaddset(&unblocked_sigs, SR_signum); 436 437 if (!ReduceSignalUsage) { 438 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 439 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 441 } 442 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 443 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 444 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 445 } 446 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 447 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 448 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 449 } 450 } 451 // Fill in signals that are blocked by all but the VM thread. 452 sigemptyset(&vm_sigs); 453 if (!ReduceSignalUsage) { 454 sigaddset(&vm_sigs, BREAK_SIGNAL); 455 } 456 debug_only(signal_sets_initialized = true); 457 458 } 459 460 // These are signals that are unblocked while a thread is running Java. 461 // (For some reason, they get blocked by default.) 462 sigset_t* os::Linux::unblocked_signals() { 463 assert(signal_sets_initialized, "Not initialized"); 464 return &unblocked_sigs; 465 } 466 467 // These are the signals that are blocked while a (non-VM) thread is 468 // running Java. Only the VM thread handles these signals. 469 sigset_t* os::Linux::vm_signals() { 470 assert(signal_sets_initialized, "Not initialized"); 471 return &vm_sigs; 472 } 473 474 // These are signals that are blocked during cond_wait to allow debugger in 475 sigset_t* os::Linux::allowdebug_blocked_signals() { 476 assert(signal_sets_initialized, "Not initialized"); 477 return &allowdebug_blocked_sigs; 478 } 479 480 void os::Linux::hotspot_sigmask(Thread* thread) { 481 482 //Save caller's signal mask before setting VM signal mask 483 sigset_t caller_sigmask; 484 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 485 486 OSThread* osthread = thread->osthread(); 487 osthread->set_caller_sigmask(caller_sigmask); 488 489 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 490 491 if (!ReduceSignalUsage) { 492 if (thread->is_VM_thread()) { 493 // Only the VM thread handles BREAK_SIGNAL ... 494 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 495 } else { 496 // ... all other threads block BREAK_SIGNAL 497 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 498 } 499 } 500 } 501 502 ////////////////////////////////////////////////////////////////////////////// 503 // detecting pthread library 504 505 void os::Linux::libpthread_init() { 506 // Save glibc and pthread version strings. 507 #if !defined(_CS_GNU_LIBC_VERSION) || \ 508 !defined(_CS_GNU_LIBPTHREAD_VERSION) 509 #error "glibc too old (< 2.3.2)" 510 #endif 511 512 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 513 assert(n > 0, "cannot retrieve glibc version"); 514 char *str = (char *)malloc(n, mtInternal); 515 confstr(_CS_GNU_LIBC_VERSION, str, n); 516 os::Linux::set_glibc_version(str); 517 518 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 519 assert(n > 0, "cannot retrieve pthread version"); 520 str = (char *)malloc(n, mtInternal); 521 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 522 os::Linux::set_libpthread_version(str); 523 } 524 525 ///////////////////////////////////////////////////////////////////////////// 526 // thread stack expansion 527 528 // os::Linux::manually_expand_stack() takes care of expanding the thread 529 // stack. Note that this is normally not needed: pthread stacks allocate 530 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 531 // committed. Therefore it is not necessary to expand the stack manually. 532 // 533 // Manually expanding the stack was historically needed on LinuxThreads 534 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 535 // it is kept to deal with very rare corner cases: 536 // 537 // For one, user may run the VM on an own implementation of threads 538 // whose stacks are - like the old LinuxThreads - implemented using 539 // mmap(MAP_GROWSDOWN). 540 // 541 // Also, this coding may be needed if the VM is running on the primordial 542 // thread. Normally we avoid running on the primordial thread; however, 543 // user may still invoke the VM on the primordial thread. 544 // 545 // The following historical comment describes the details about running 546 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 547 548 549 // Force Linux kernel to expand current thread stack. If "bottom" is close 550 // to the stack guard, caller should block all signals. 551 // 552 // MAP_GROWSDOWN: 553 // A special mmap() flag that is used to implement thread stacks. It tells 554 // kernel that the memory region should extend downwards when needed. This 555 // allows early versions of LinuxThreads to only mmap the first few pages 556 // when creating a new thread. Linux kernel will automatically expand thread 557 // stack as needed (on page faults). 558 // 559 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 560 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 561 // region, it's hard to tell if the fault is due to a legitimate stack 562 // access or because of reading/writing non-exist memory (e.g. buffer 563 // overrun). As a rule, if the fault happens below current stack pointer, 564 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 565 // application (see Linux kernel fault.c). 566 // 567 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 568 // stack overflow detection. 569 // 570 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 571 // not use MAP_GROWSDOWN. 572 // 573 // To get around the problem and allow stack banging on Linux, we need to 574 // manually expand thread stack after receiving the SIGSEGV. 575 // 576 // There are two ways to expand thread stack to address "bottom", we used 577 // both of them in JVM before 1.5: 578 // 1. adjust stack pointer first so that it is below "bottom", and then 579 // touch "bottom" 580 // 2. mmap() the page in question 581 // 582 // Now alternate signal stack is gone, it's harder to use 2. For instance, 583 // if current sp is already near the lower end of page 101, and we need to 584 // call mmap() to map page 100, it is possible that part of the mmap() frame 585 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 586 // That will destroy the mmap() frame and cause VM to crash. 587 // 588 // The following code works by adjusting sp first, then accessing the "bottom" 589 // page to force a page fault. Linux kernel will then automatically expand the 590 // stack mapping. 591 // 592 // _expand_stack_to() assumes its frame size is less than page size, which 593 // should always be true if the function is not inlined. 594 595 static void NOINLINE _expand_stack_to(address bottom) { 596 address sp; 597 size_t size; 598 volatile char *p; 599 600 // Adjust bottom to point to the largest address within the same page, it 601 // gives us a one-page buffer if alloca() allocates slightly more memory. 602 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 603 bottom += os::Linux::page_size() - 1; 604 605 // sp might be slightly above current stack pointer; if that's the case, we 606 // will alloca() a little more space than necessary, which is OK. Don't use 607 // os::current_stack_pointer(), as its result can be slightly below current 608 // stack pointer, causing us to not alloca enough to reach "bottom". 609 sp = (address)&sp; 610 611 if (sp > bottom) { 612 size = sp - bottom; 613 p = (volatile char *)alloca(size); 614 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 615 p[0] = '\0'; 616 } 617 } 618 619 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 620 assert(t!=NULL, "just checking"); 621 assert(t->osthread()->expanding_stack(), "expand should be set"); 622 assert(t->stack_base() != NULL, "stack_base was not initialized"); 623 624 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 625 sigset_t mask_all, old_sigset; 626 sigfillset(&mask_all); 627 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 628 _expand_stack_to(addr); 629 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 630 return true; 631 } 632 return false; 633 } 634 635 ////////////////////////////////////////////////////////////////////////////// 636 // create new thread 637 638 // Thread start routine for all newly created threads 639 static void *thread_native_entry(Thread *thread) { 640 // Try to randomize the cache line index of hot stack frames. 641 // This helps when threads of the same stack traces evict each other's 642 // cache lines. The threads can be either from the same JVM instance, or 643 // from different JVM instances. The benefit is especially true for 644 // processors with hyperthreading technology. 645 static int counter = 0; 646 int pid = os::current_process_id(); 647 alloca(((pid ^ counter++) & 7) * 128); 648 649 thread->initialize_thread_current(); 650 651 OSThread* osthread = thread->osthread(); 652 Monitor* sync = osthread->startThread_lock(); 653 654 osthread->set_thread_id(os::current_thread_id()); 655 656 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 657 os::current_thread_id(), (uintx) pthread_self()); 658 659 if (UseNUMA) { 660 int lgrp_id = os::numa_get_group_id(); 661 if (lgrp_id != -1) { 662 thread->set_lgrp_id(lgrp_id); 663 } 664 } 665 // initialize signal mask for this thread 666 os::Linux::hotspot_sigmask(thread); 667 668 // initialize floating point control register 669 os::Linux::init_thread_fpu_state(); 670 671 // handshaking with parent thread 672 { 673 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 674 675 // notify parent thread 676 osthread->set_state(INITIALIZED); 677 sync->notify_all(); 678 679 // wait until os::start_thread() 680 while (osthread->get_state() == INITIALIZED) { 681 sync->wait(Mutex::_no_safepoint_check_flag); 682 } 683 } 684 685 // call one more level start routine 686 thread->run(); 687 688 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 689 os::current_thread_id(), (uintx) pthread_self()); 690 691 // If a thread has not deleted itself ("delete this") as part of its 692 // termination sequence, we have to ensure thread-local-storage is 693 // cleared before we actually terminate. No threads should ever be 694 // deleted asynchronously with respect to their termination. 695 if (Thread::current_or_null_safe() != NULL) { 696 assert(Thread::current_or_null_safe() == thread, "current thread is wrong"); 697 thread->clear_thread_current(); 698 } 699 700 return 0; 701 } 702 703 bool os::create_thread(Thread* thread, ThreadType thr_type, 704 size_t req_stack_size) { 705 assert(thread->osthread() == NULL, "caller responsible"); 706 707 // Allocate the OSThread object 708 OSThread* osthread = new OSThread(NULL, NULL); 709 if (osthread == NULL) { 710 return false; 711 } 712 713 // set the correct thread state 714 osthread->set_thread_type(thr_type); 715 716 // Initial state is ALLOCATED but not INITIALIZED 717 osthread->set_state(ALLOCATED); 718 719 thread->set_osthread(osthread); 720 721 // init thread attributes 722 pthread_attr_t attr; 723 pthread_attr_init(&attr); 724 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 725 726 // Calculate stack size if it's not specified by caller. 727 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 728 // In the Linux NPTL pthread implementation the guard size mechanism 729 // is not implemented properly. The posix standard requires adding 730 // the size of the guard pages to the stack size, instead Linux 731 // takes the space out of 'stacksize'. Thus we adapt the requested 732 // stack_size by the size of the guard pages to mimick proper 733 // behaviour. 734 stack_size = align_size_up(stack_size + os::Linux::default_guard_size(thr_type), vm_page_size()); 735 pthread_attr_setstacksize(&attr, stack_size); 736 737 // glibc guard page 738 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 739 740 ThreadState state; 741 742 { 743 pthread_t tid; 744 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 745 746 char buf[64]; 747 if (ret == 0) { 748 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 749 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 750 } else { 751 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 752 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 753 } 754 755 pthread_attr_destroy(&attr); 756 757 if (ret != 0) { 758 // Need to clean up stuff we've allocated so far 759 thread->set_osthread(NULL); 760 delete osthread; 761 return false; 762 } 763 764 // Store pthread info into the OSThread 765 osthread->set_pthread_id(tid); 766 767 // Wait until child thread is either initialized or aborted 768 { 769 Monitor* sync_with_child = osthread->startThread_lock(); 770 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 771 while ((state = osthread->get_state()) == ALLOCATED) { 772 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 773 } 774 } 775 } 776 777 // Aborted due to thread limit being reached 778 if (state == ZOMBIE) { 779 thread->set_osthread(NULL); 780 delete osthread; 781 return false; 782 } 783 784 // The thread is returned suspended (in state INITIALIZED), 785 // and is started higher up in the call chain 786 assert(state == INITIALIZED, "race condition"); 787 return true; 788 } 789 790 ///////////////////////////////////////////////////////////////////////////// 791 // attach existing thread 792 793 // bootstrap the main thread 794 bool os::create_main_thread(JavaThread* thread) { 795 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 796 return create_attached_thread(thread); 797 } 798 799 bool os::create_attached_thread(JavaThread* thread) { 800 #ifdef ASSERT 801 thread->verify_not_published(); 802 #endif 803 804 // Allocate the OSThread object 805 OSThread* osthread = new OSThread(NULL, NULL); 806 807 if (osthread == NULL) { 808 return false; 809 } 810 811 // Store pthread info into the OSThread 812 osthread->set_thread_id(os::Linux::gettid()); 813 osthread->set_pthread_id(::pthread_self()); 814 815 // initialize floating point control register 816 os::Linux::init_thread_fpu_state(); 817 818 // Initial thread state is RUNNABLE 819 osthread->set_state(RUNNABLE); 820 821 thread->set_osthread(osthread); 822 823 if (UseNUMA) { 824 int lgrp_id = os::numa_get_group_id(); 825 if (lgrp_id != -1) { 826 thread->set_lgrp_id(lgrp_id); 827 } 828 } 829 830 if (os::Linux::is_initial_thread()) { 831 // If current thread is initial thread, its stack is mapped on demand, 832 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 833 // the entire stack region to avoid SEGV in stack banging. 834 // It is also useful to get around the heap-stack-gap problem on SuSE 835 // kernel (see 4821821 for details). We first expand stack to the top 836 // of yellow zone, then enable stack yellow zone (order is significant, 837 // enabling yellow zone first will crash JVM on SuSE Linux), so there 838 // is no gap between the last two virtual memory regions. 839 840 JavaThread *jt = (JavaThread *)thread; 841 address addr = jt->stack_reserved_zone_base(); 842 assert(addr != NULL, "initialization problem?"); 843 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 844 845 osthread->set_expanding_stack(); 846 os::Linux::manually_expand_stack(jt, addr); 847 osthread->clear_expanding_stack(); 848 } 849 850 // initialize signal mask for this thread 851 // and save the caller's signal mask 852 os::Linux::hotspot_sigmask(thread); 853 854 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 855 os::current_thread_id(), (uintx) pthread_self()); 856 857 return true; 858 } 859 860 void os::pd_start_thread(Thread* thread) { 861 OSThread * osthread = thread->osthread(); 862 assert(osthread->get_state() != INITIALIZED, "just checking"); 863 Monitor* sync_with_child = osthread->startThread_lock(); 864 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 865 sync_with_child->notify(); 866 } 867 868 // Free Linux resources related to the OSThread 869 void os::free_thread(OSThread* osthread) { 870 assert(osthread != NULL, "osthread not set"); 871 872 // We are told to free resources of the argument thread, 873 // but we can only really operate on the current thread. 874 assert(Thread::current()->osthread() == osthread, 875 "os::free_thread but not current thread"); 876 877 #ifdef ASSERT 878 sigset_t current; 879 sigemptyset(¤t); 880 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 881 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 882 #endif 883 884 // Restore caller's signal mask 885 sigset_t sigmask = osthread->caller_sigmask(); 886 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 887 888 delete osthread; 889 } 890 891 ////////////////////////////////////////////////////////////////////////////// 892 // initial thread 893 894 // Check if current thread is the initial thread, similar to Solaris thr_main. 895 bool os::Linux::is_initial_thread(void) { 896 char dummy; 897 // If called before init complete, thread stack bottom will be null. 898 // Can be called if fatal error occurs before initialization. 899 if (initial_thread_stack_bottom() == NULL) return false; 900 assert(initial_thread_stack_bottom() != NULL && 901 initial_thread_stack_size() != 0, 902 "os::init did not locate initial thread's stack region"); 903 if ((address)&dummy >= initial_thread_stack_bottom() && 904 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 905 return true; 906 } else { 907 return false; 908 } 909 } 910 911 // Find the virtual memory area that contains addr 912 static bool find_vma(address addr, address* vma_low, address* vma_high) { 913 FILE *fp = fopen("/proc/self/maps", "r"); 914 if (fp) { 915 address low, high; 916 while (!feof(fp)) { 917 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 918 if (low <= addr && addr < high) { 919 if (vma_low) *vma_low = low; 920 if (vma_high) *vma_high = high; 921 fclose(fp); 922 return true; 923 } 924 } 925 for (;;) { 926 int ch = fgetc(fp); 927 if (ch == EOF || ch == (int)'\n') break; 928 } 929 } 930 fclose(fp); 931 } 932 return false; 933 } 934 935 // Locate initial thread stack. This special handling of initial thread stack 936 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 937 // bogus value for initial thread. 938 void os::Linux::capture_initial_stack(size_t max_size) { 939 // stack size is the easy part, get it from RLIMIT_STACK 940 struct rlimit rlim; 941 getrlimit(RLIMIT_STACK, &rlim); 942 size_t stack_size = rlim.rlim_cur; 943 944 // 6308388: a bug in ld.so will relocate its own .data section to the 945 // lower end of primordial stack; reduce ulimit -s value a little bit 946 // so we won't install guard page on ld.so's data section. 947 stack_size -= 2 * page_size(); 948 949 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 950 // 7.1, in both cases we will get 2G in return value. 951 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 952 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 953 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 954 // in case other parts in glibc still assumes 2M max stack size. 955 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 956 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 957 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 958 stack_size = 2 * K * K IA64_ONLY(*2); 959 } 960 // Try to figure out where the stack base (top) is. This is harder. 961 // 962 // When an application is started, glibc saves the initial stack pointer in 963 // a global variable "__libc_stack_end", which is then used by system 964 // libraries. __libc_stack_end should be pretty close to stack top. The 965 // variable is available since the very early days. However, because it is 966 // a private interface, it could disappear in the future. 967 // 968 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 969 // to __libc_stack_end, it is very close to stack top, but isn't the real 970 // stack top. Note that /proc may not exist if VM is running as a chroot 971 // program, so reading /proc/<pid>/stat could fail. Also the contents of 972 // /proc/<pid>/stat could change in the future (though unlikely). 973 // 974 // We try __libc_stack_end first. If that doesn't work, look for 975 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 976 // as a hint, which should work well in most cases. 977 978 uintptr_t stack_start; 979 980 // try __libc_stack_end first 981 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 982 if (p && *p) { 983 stack_start = *p; 984 } else { 985 // see if we can get the start_stack field from /proc/self/stat 986 FILE *fp; 987 int pid; 988 char state; 989 int ppid; 990 int pgrp; 991 int session; 992 int nr; 993 int tpgrp; 994 unsigned long flags; 995 unsigned long minflt; 996 unsigned long cminflt; 997 unsigned long majflt; 998 unsigned long cmajflt; 999 unsigned long utime; 1000 unsigned long stime; 1001 long cutime; 1002 long cstime; 1003 long prio; 1004 long nice; 1005 long junk; 1006 long it_real; 1007 uintptr_t start; 1008 uintptr_t vsize; 1009 intptr_t rss; 1010 uintptr_t rsslim; 1011 uintptr_t scodes; 1012 uintptr_t ecode; 1013 int i; 1014 1015 // Figure what the primordial thread stack base is. Code is inspired 1016 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1017 // followed by command name surrounded by parentheses, state, etc. 1018 char stat[2048]; 1019 int statlen; 1020 1021 fp = fopen("/proc/self/stat", "r"); 1022 if (fp) { 1023 statlen = fread(stat, 1, 2047, fp); 1024 stat[statlen] = '\0'; 1025 fclose(fp); 1026 1027 // Skip pid and the command string. Note that we could be dealing with 1028 // weird command names, e.g. user could decide to rename java launcher 1029 // to "java 1.4.2 :)", then the stat file would look like 1030 // 1234 (java 1.4.2 :)) R ... ... 1031 // We don't really need to know the command string, just find the last 1032 // occurrence of ")" and then start parsing from there. See bug 4726580. 1033 char * s = strrchr(stat, ')'); 1034 1035 i = 0; 1036 if (s) { 1037 // Skip blank chars 1038 do { s++; } while (s && isspace(*s)); 1039 1040 #define _UFM UINTX_FORMAT 1041 #define _DFM INTX_FORMAT 1042 1043 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1044 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 1045 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1046 &state, // 3 %c 1047 &ppid, // 4 %d 1048 &pgrp, // 5 %d 1049 &session, // 6 %d 1050 &nr, // 7 %d 1051 &tpgrp, // 8 %d 1052 &flags, // 9 %lu 1053 &minflt, // 10 %lu 1054 &cminflt, // 11 %lu 1055 &majflt, // 12 %lu 1056 &cmajflt, // 13 %lu 1057 &utime, // 14 %lu 1058 &stime, // 15 %lu 1059 &cutime, // 16 %ld 1060 &cstime, // 17 %ld 1061 &prio, // 18 %ld 1062 &nice, // 19 %ld 1063 &junk, // 20 %ld 1064 &it_real, // 21 %ld 1065 &start, // 22 UINTX_FORMAT 1066 &vsize, // 23 UINTX_FORMAT 1067 &rss, // 24 INTX_FORMAT 1068 &rsslim, // 25 UINTX_FORMAT 1069 &scodes, // 26 UINTX_FORMAT 1070 &ecode, // 27 UINTX_FORMAT 1071 &stack_start); // 28 UINTX_FORMAT 1072 } 1073 1074 #undef _UFM 1075 #undef _DFM 1076 1077 if (i != 28 - 2) { 1078 assert(false, "Bad conversion from /proc/self/stat"); 1079 // product mode - assume we are the initial thread, good luck in the 1080 // embedded case. 1081 warning("Can't detect initial thread stack location - bad conversion"); 1082 stack_start = (uintptr_t) &rlim; 1083 } 1084 } else { 1085 // For some reason we can't open /proc/self/stat (for example, running on 1086 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1087 // most cases, so don't abort: 1088 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1089 stack_start = (uintptr_t) &rlim; 1090 } 1091 } 1092 1093 // Now we have a pointer (stack_start) very close to the stack top, the 1094 // next thing to do is to figure out the exact location of stack top. We 1095 // can find out the virtual memory area that contains stack_start by 1096 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1097 // and its upper limit is the real stack top. (again, this would fail if 1098 // running inside chroot, because /proc may not exist.) 1099 1100 uintptr_t stack_top; 1101 address low, high; 1102 if (find_vma((address)stack_start, &low, &high)) { 1103 // success, "high" is the true stack top. (ignore "low", because initial 1104 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1105 stack_top = (uintptr_t)high; 1106 } else { 1107 // failed, likely because /proc/self/maps does not exist 1108 warning("Can't detect initial thread stack location - find_vma failed"); 1109 // best effort: stack_start is normally within a few pages below the real 1110 // stack top, use it as stack top, and reduce stack size so we won't put 1111 // guard page outside stack. 1112 stack_top = stack_start; 1113 stack_size -= 16 * page_size(); 1114 } 1115 1116 // stack_top could be partially down the page so align it 1117 stack_top = align_size_up(stack_top, page_size()); 1118 1119 if (max_size && stack_size > max_size) { 1120 _initial_thread_stack_size = max_size; 1121 } else { 1122 _initial_thread_stack_size = stack_size; 1123 } 1124 1125 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1126 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1127 } 1128 1129 //////////////////////////////////////////////////////////////////////////////// 1130 // time support 1131 1132 // Time since start-up in seconds to a fine granularity. 1133 // Used by VMSelfDestructTimer and the MemProfiler. 1134 double os::elapsedTime() { 1135 1136 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1137 } 1138 1139 jlong os::elapsed_counter() { 1140 return javaTimeNanos() - initial_time_count; 1141 } 1142 1143 jlong os::elapsed_frequency() { 1144 return NANOSECS_PER_SEC; // nanosecond resolution 1145 } 1146 1147 bool os::supports_vtime() { return true; } 1148 bool os::enable_vtime() { return false; } 1149 bool os::vtime_enabled() { return false; } 1150 1151 double os::elapsedVTime() { 1152 struct rusage usage; 1153 int retval = getrusage(RUSAGE_THREAD, &usage); 1154 if (retval == 0) { 1155 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1156 } else { 1157 // better than nothing, but not much 1158 return elapsedTime(); 1159 } 1160 } 1161 1162 jlong os::javaTimeMillis() { 1163 timeval time; 1164 int status = gettimeofday(&time, NULL); 1165 assert(status != -1, "linux error"); 1166 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1167 } 1168 1169 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1170 timeval time; 1171 int status = gettimeofday(&time, NULL); 1172 assert(status != -1, "linux error"); 1173 seconds = jlong(time.tv_sec); 1174 nanos = jlong(time.tv_usec) * 1000; 1175 } 1176 1177 1178 #ifndef CLOCK_MONOTONIC 1179 #define CLOCK_MONOTONIC (1) 1180 #endif 1181 1182 void os::Linux::clock_init() { 1183 // we do dlopen's in this particular order due to bug in linux 1184 // dynamical loader (see 6348968) leading to crash on exit 1185 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1186 if (handle == NULL) { 1187 handle = dlopen("librt.so", RTLD_LAZY); 1188 } 1189 1190 if (handle) { 1191 int (*clock_getres_func)(clockid_t, struct timespec*) = 1192 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1193 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1194 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1195 if (clock_getres_func && clock_gettime_func) { 1196 // See if monotonic clock is supported by the kernel. Note that some 1197 // early implementations simply return kernel jiffies (updated every 1198 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1199 // for nano time (though the monotonic property is still nice to have). 1200 // It's fixed in newer kernels, however clock_getres() still returns 1201 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1202 // resolution for now. Hopefully as people move to new kernels, this 1203 // won't be a problem. 1204 struct timespec res; 1205 struct timespec tp; 1206 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1207 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1208 // yes, monotonic clock is supported 1209 _clock_gettime = clock_gettime_func; 1210 return; 1211 } else { 1212 // close librt if there is no monotonic clock 1213 dlclose(handle); 1214 } 1215 } 1216 } 1217 warning("No monotonic clock was available - timed services may " \ 1218 "be adversely affected if the time-of-day clock changes"); 1219 } 1220 1221 #ifndef SYS_clock_getres 1222 #if defined(X86) || defined(PPC64) || defined(S390) 1223 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261) 1224 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1225 #else 1226 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1227 #define sys_clock_getres(x,y) -1 1228 #endif 1229 #else 1230 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1231 #endif 1232 1233 void os::Linux::fast_thread_clock_init() { 1234 if (!UseLinuxPosixThreadCPUClocks) { 1235 return; 1236 } 1237 clockid_t clockid; 1238 struct timespec tp; 1239 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1240 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1241 1242 // Switch to using fast clocks for thread cpu time if 1243 // the sys_clock_getres() returns 0 error code. 1244 // Note, that some kernels may support the current thread 1245 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1246 // returned by the pthread_getcpuclockid(). 1247 // If the fast Posix clocks are supported then the sys_clock_getres() 1248 // must return at least tp.tv_sec == 0 which means a resolution 1249 // better than 1 sec. This is extra check for reliability. 1250 1251 if (pthread_getcpuclockid_func && 1252 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1253 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1254 _supports_fast_thread_cpu_time = true; 1255 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1256 } 1257 } 1258 1259 jlong os::javaTimeNanos() { 1260 if (os::supports_monotonic_clock()) { 1261 struct timespec tp; 1262 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1263 assert(status == 0, "gettime error"); 1264 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1265 return result; 1266 } else { 1267 timeval time; 1268 int status = gettimeofday(&time, NULL); 1269 assert(status != -1, "linux error"); 1270 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1271 return 1000 * usecs; 1272 } 1273 } 1274 1275 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1276 if (os::supports_monotonic_clock()) { 1277 info_ptr->max_value = ALL_64_BITS; 1278 1279 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1280 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1281 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1282 } else { 1283 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1284 info_ptr->max_value = ALL_64_BITS; 1285 1286 // gettimeofday is a real time clock so it skips 1287 info_ptr->may_skip_backward = true; 1288 info_ptr->may_skip_forward = true; 1289 } 1290 1291 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1292 } 1293 1294 // Return the real, user, and system times in seconds from an 1295 // arbitrary fixed point in the past. 1296 bool os::getTimesSecs(double* process_real_time, 1297 double* process_user_time, 1298 double* process_system_time) { 1299 struct tms ticks; 1300 clock_t real_ticks = times(&ticks); 1301 1302 if (real_ticks == (clock_t) (-1)) { 1303 return false; 1304 } else { 1305 double ticks_per_second = (double) clock_tics_per_sec; 1306 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1307 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1308 *process_real_time = ((double) real_ticks) / ticks_per_second; 1309 1310 return true; 1311 } 1312 } 1313 1314 1315 char * os::local_time_string(char *buf, size_t buflen) { 1316 struct tm t; 1317 time_t long_time; 1318 time(&long_time); 1319 localtime_r(&long_time, &t); 1320 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1321 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1322 t.tm_hour, t.tm_min, t.tm_sec); 1323 return buf; 1324 } 1325 1326 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1327 return localtime_r(clock, res); 1328 } 1329 1330 //////////////////////////////////////////////////////////////////////////////// 1331 // runtime exit support 1332 1333 // Note: os::shutdown() might be called very early during initialization, or 1334 // called from signal handler. Before adding something to os::shutdown(), make 1335 // sure it is async-safe and can handle partially initialized VM. 1336 void os::shutdown() { 1337 1338 // allow PerfMemory to attempt cleanup of any persistent resources 1339 perfMemory_exit(); 1340 1341 // needs to remove object in file system 1342 AttachListener::abort(); 1343 1344 // flush buffered output, finish log files 1345 ostream_abort(); 1346 1347 // Check for abort hook 1348 abort_hook_t abort_hook = Arguments::abort_hook(); 1349 if (abort_hook != NULL) { 1350 abort_hook(); 1351 } 1352 1353 } 1354 1355 // Note: os::abort() might be called very early during initialization, or 1356 // called from signal handler. Before adding something to os::abort(), make 1357 // sure it is async-safe and can handle partially initialized VM. 1358 void os::abort(bool dump_core, void* siginfo, const void* context) { 1359 os::shutdown(); 1360 if (dump_core) { 1361 #ifndef PRODUCT 1362 fdStream out(defaultStream::output_fd()); 1363 out.print_raw("Current thread is "); 1364 char buf[16]; 1365 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1366 out.print_raw_cr(buf); 1367 out.print_raw_cr("Dumping core ..."); 1368 #endif 1369 ::abort(); // dump core 1370 } 1371 1372 ::exit(1); 1373 } 1374 1375 // Die immediately, no exit hook, no abort hook, no cleanup. 1376 void os::die() { 1377 ::abort(); 1378 } 1379 1380 1381 // This method is a copy of JDK's sysGetLastErrorString 1382 // from src/solaris/hpi/src/system_md.c 1383 1384 size_t os::lasterror(char *buf, size_t len) { 1385 if (errno == 0) return 0; 1386 1387 const char *s = os::strerror(errno); 1388 size_t n = ::strlen(s); 1389 if (n >= len) { 1390 n = len - 1; 1391 } 1392 ::strncpy(buf, s, n); 1393 buf[n] = '\0'; 1394 return n; 1395 } 1396 1397 // thread_id is kernel thread id (similar to Solaris LWP id) 1398 intx os::current_thread_id() { return os::Linux::gettid(); } 1399 int os::current_process_id() { 1400 return ::getpid(); 1401 } 1402 1403 // DLL functions 1404 1405 const char* os::dll_file_extension() { return ".so"; } 1406 1407 // This must be hard coded because it's the system's temporary 1408 // directory not the java application's temp directory, ala java.io.tmpdir. 1409 const char* os::get_temp_directory() { return "/tmp"; } 1410 1411 static bool file_exists(const char* filename) { 1412 struct stat statbuf; 1413 if (filename == NULL || strlen(filename) == 0) { 1414 return false; 1415 } 1416 return os::stat(filename, &statbuf) == 0; 1417 } 1418 1419 bool os::dll_build_name(char* buffer, size_t buflen, 1420 const char* pname, const char* fname) { 1421 bool retval = false; 1422 // Copied from libhpi 1423 const size_t pnamelen = pname ? strlen(pname) : 0; 1424 1425 // Return error on buffer overflow. 1426 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1427 return retval; 1428 } 1429 1430 if (pnamelen == 0) { 1431 snprintf(buffer, buflen, "lib%s.so", fname); 1432 retval = true; 1433 } else if (strchr(pname, *os::path_separator()) != NULL) { 1434 int n; 1435 char** pelements = split_path(pname, &n); 1436 if (pelements == NULL) { 1437 return false; 1438 } 1439 for (int i = 0; i < n; i++) { 1440 // Really shouldn't be NULL, but check can't hurt 1441 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1442 continue; // skip the empty path values 1443 } 1444 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1445 if (file_exists(buffer)) { 1446 retval = true; 1447 break; 1448 } 1449 } 1450 // release the storage 1451 for (int i = 0; i < n; i++) { 1452 if (pelements[i] != NULL) { 1453 FREE_C_HEAP_ARRAY(char, pelements[i]); 1454 } 1455 } 1456 if (pelements != NULL) { 1457 FREE_C_HEAP_ARRAY(char*, pelements); 1458 } 1459 } else { 1460 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1461 retval = true; 1462 } 1463 return retval; 1464 } 1465 1466 // check if addr is inside libjvm.so 1467 bool os::address_is_in_vm(address addr) { 1468 static address libjvm_base_addr; 1469 Dl_info dlinfo; 1470 1471 if (libjvm_base_addr == NULL) { 1472 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1473 libjvm_base_addr = (address)dlinfo.dli_fbase; 1474 } 1475 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1476 } 1477 1478 if (dladdr((void *)addr, &dlinfo) != 0) { 1479 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1480 } 1481 1482 return false; 1483 } 1484 1485 bool os::dll_address_to_function_name(address addr, char *buf, 1486 int buflen, int *offset, 1487 bool demangle) { 1488 // buf is not optional, but offset is optional 1489 assert(buf != NULL, "sanity check"); 1490 1491 Dl_info dlinfo; 1492 1493 if (dladdr((void*)addr, &dlinfo) != 0) { 1494 // see if we have a matching symbol 1495 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1496 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1497 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1498 } 1499 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1500 return true; 1501 } 1502 // no matching symbol so try for just file info 1503 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1504 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1505 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1506 return true; 1507 } 1508 } 1509 } 1510 1511 buf[0] = '\0'; 1512 if (offset != NULL) *offset = -1; 1513 return false; 1514 } 1515 1516 struct _address_to_library_name { 1517 address addr; // input : memory address 1518 size_t buflen; // size of fname 1519 char* fname; // output: library name 1520 address base; // library base addr 1521 }; 1522 1523 static int address_to_library_name_callback(struct dl_phdr_info *info, 1524 size_t size, void *data) { 1525 int i; 1526 bool found = false; 1527 address libbase = NULL; 1528 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1529 1530 // iterate through all loadable segments 1531 for (i = 0; i < info->dlpi_phnum; i++) { 1532 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1533 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1534 // base address of a library is the lowest address of its loaded 1535 // segments. 1536 if (libbase == NULL || libbase > segbase) { 1537 libbase = segbase; 1538 } 1539 // see if 'addr' is within current segment 1540 if (segbase <= d->addr && 1541 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1542 found = true; 1543 } 1544 } 1545 } 1546 1547 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1548 // so dll_address_to_library_name() can fall through to use dladdr() which 1549 // can figure out executable name from argv[0]. 1550 if (found && info->dlpi_name && info->dlpi_name[0]) { 1551 d->base = libbase; 1552 if (d->fname) { 1553 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1554 } 1555 return 1; 1556 } 1557 return 0; 1558 } 1559 1560 bool os::dll_address_to_library_name(address addr, char* buf, 1561 int buflen, int* offset) { 1562 // buf is not optional, but offset is optional 1563 assert(buf != NULL, "sanity check"); 1564 1565 Dl_info dlinfo; 1566 struct _address_to_library_name data; 1567 1568 // There is a bug in old glibc dladdr() implementation that it could resolve 1569 // to wrong library name if the .so file has a base address != NULL. Here 1570 // we iterate through the program headers of all loaded libraries to find 1571 // out which library 'addr' really belongs to. This workaround can be 1572 // removed once the minimum requirement for glibc is moved to 2.3.x. 1573 data.addr = addr; 1574 data.fname = buf; 1575 data.buflen = buflen; 1576 data.base = NULL; 1577 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1578 1579 if (rslt) { 1580 // buf already contains library name 1581 if (offset) *offset = addr - data.base; 1582 return true; 1583 } 1584 if (dladdr((void*)addr, &dlinfo) != 0) { 1585 if (dlinfo.dli_fname != NULL) { 1586 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1587 } 1588 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1589 *offset = addr - (address)dlinfo.dli_fbase; 1590 } 1591 return true; 1592 } 1593 1594 buf[0] = '\0'; 1595 if (offset) *offset = -1; 1596 return false; 1597 } 1598 1599 // Loads .dll/.so and 1600 // in case of error it checks if .dll/.so was built for the 1601 // same architecture as Hotspot is running on 1602 1603 1604 // Remember the stack's state. The Linux dynamic linker will change 1605 // the stack to 'executable' at most once, so we must safepoint only once. 1606 bool os::Linux::_stack_is_executable = false; 1607 1608 // VM operation that loads a library. This is necessary if stack protection 1609 // of the Java stacks can be lost during loading the library. If we 1610 // do not stop the Java threads, they can stack overflow before the stacks 1611 // are protected again. 1612 class VM_LinuxDllLoad: public VM_Operation { 1613 private: 1614 const char *_filename; 1615 char *_ebuf; 1616 int _ebuflen; 1617 void *_lib; 1618 public: 1619 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1620 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1621 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1622 void doit() { 1623 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1624 os::Linux::_stack_is_executable = true; 1625 } 1626 void* loaded_library() { return _lib; } 1627 }; 1628 1629 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1630 void * result = NULL; 1631 bool load_attempted = false; 1632 1633 // Check whether the library to load might change execution rights 1634 // of the stack. If they are changed, the protection of the stack 1635 // guard pages will be lost. We need a safepoint to fix this. 1636 // 1637 // See Linux man page execstack(8) for more info. 1638 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1639 ElfFile ef(filename); 1640 if (!ef.specifies_noexecstack()) { 1641 if (!is_init_completed()) { 1642 os::Linux::_stack_is_executable = true; 1643 // This is OK - No Java threads have been created yet, and hence no 1644 // stack guard pages to fix. 1645 // 1646 // This should happen only when you are building JDK7 using a very 1647 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1648 // 1649 // Dynamic loader will make all stacks executable after 1650 // this function returns, and will not do that again. 1651 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1652 } else { 1653 warning("You have loaded library %s which might have disabled stack guard. " 1654 "The VM will try to fix the stack guard now.\n" 1655 "It's highly recommended that you fix the library with " 1656 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1657 filename); 1658 1659 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1660 JavaThread *jt = JavaThread::current(); 1661 if (jt->thread_state() != _thread_in_native) { 1662 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1663 // that requires ExecStack. Cannot enter safe point. Let's give up. 1664 warning("Unable to fix stack guard. Giving up."); 1665 } else { 1666 if (!LoadExecStackDllInVMThread) { 1667 // This is for the case where the DLL has an static 1668 // constructor function that executes JNI code. We cannot 1669 // load such DLLs in the VMThread. 1670 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1671 } 1672 1673 ThreadInVMfromNative tiv(jt); 1674 debug_only(VMNativeEntryWrapper vew;) 1675 1676 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1677 VMThread::execute(&op); 1678 if (LoadExecStackDllInVMThread) { 1679 result = op.loaded_library(); 1680 } 1681 load_attempted = true; 1682 } 1683 } 1684 } 1685 } 1686 1687 if (!load_attempted) { 1688 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1689 } 1690 1691 if (result != NULL) { 1692 // Successful loading 1693 return result; 1694 } 1695 1696 Elf32_Ehdr elf_head; 1697 int diag_msg_max_length=ebuflen-strlen(ebuf); 1698 char* diag_msg_buf=ebuf+strlen(ebuf); 1699 1700 if (diag_msg_max_length==0) { 1701 // No more space in ebuf for additional diagnostics message 1702 return NULL; 1703 } 1704 1705 1706 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1707 1708 if (file_descriptor < 0) { 1709 // Can't open library, report dlerror() message 1710 return NULL; 1711 } 1712 1713 bool failed_to_read_elf_head= 1714 (sizeof(elf_head)!= 1715 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1716 1717 ::close(file_descriptor); 1718 if (failed_to_read_elf_head) { 1719 // file i/o error - report dlerror() msg 1720 return NULL; 1721 } 1722 1723 typedef struct { 1724 Elf32_Half code; // Actual value as defined in elf.h 1725 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1726 unsigned char elf_class; // 32 or 64 bit 1727 unsigned char endianess; // MSB or LSB 1728 char* name; // String representation 1729 } arch_t; 1730 1731 #ifndef EM_486 1732 #define EM_486 6 /* Intel 80486 */ 1733 #endif 1734 #ifndef EM_AARCH64 1735 #define EM_AARCH64 183 /* ARM AARCH64 */ 1736 #endif 1737 1738 static const arch_t arch_array[]={ 1739 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1740 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1741 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1742 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1743 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1744 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1745 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1746 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1747 #if defined(VM_LITTLE_ENDIAN) 1748 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1749 #else 1750 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1751 #endif 1752 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1753 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1754 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1755 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1756 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1757 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1758 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1759 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1760 }; 1761 1762 #if (defined IA32) 1763 static Elf32_Half running_arch_code=EM_386; 1764 #elif (defined AMD64) 1765 static Elf32_Half running_arch_code=EM_X86_64; 1766 #elif (defined IA64) 1767 static Elf32_Half running_arch_code=EM_IA_64; 1768 #elif (defined __sparc) && (defined _LP64) 1769 static Elf32_Half running_arch_code=EM_SPARCV9; 1770 #elif (defined __sparc) && (!defined _LP64) 1771 static Elf32_Half running_arch_code=EM_SPARC; 1772 #elif (defined __powerpc64__) 1773 static Elf32_Half running_arch_code=EM_PPC64; 1774 #elif (defined __powerpc__) 1775 static Elf32_Half running_arch_code=EM_PPC; 1776 #elif (defined AARCH64) 1777 static Elf32_Half running_arch_code=EM_AARCH64; 1778 #elif (defined ARM) 1779 static Elf32_Half running_arch_code=EM_ARM; 1780 #elif (defined S390) 1781 static Elf32_Half running_arch_code=EM_S390; 1782 #elif (defined ALPHA) 1783 static Elf32_Half running_arch_code=EM_ALPHA; 1784 #elif (defined MIPSEL) 1785 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1786 #elif (defined PARISC) 1787 static Elf32_Half running_arch_code=EM_PARISC; 1788 #elif (defined MIPS) 1789 static Elf32_Half running_arch_code=EM_MIPS; 1790 #elif (defined M68K) 1791 static Elf32_Half running_arch_code=EM_68K; 1792 #else 1793 #error Method os::dll_load requires that one of following is defined:\ 1794 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc 1795 #endif 1796 1797 // Identify compatability class for VM's architecture and library's architecture 1798 // Obtain string descriptions for architectures 1799 1800 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1801 int running_arch_index=-1; 1802 1803 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1804 if (running_arch_code == arch_array[i].code) { 1805 running_arch_index = i; 1806 } 1807 if (lib_arch.code == arch_array[i].code) { 1808 lib_arch.compat_class = arch_array[i].compat_class; 1809 lib_arch.name = arch_array[i].name; 1810 } 1811 } 1812 1813 assert(running_arch_index != -1, 1814 "Didn't find running architecture code (running_arch_code) in arch_array"); 1815 if (running_arch_index == -1) { 1816 // Even though running architecture detection failed 1817 // we may still continue with reporting dlerror() message 1818 return NULL; 1819 } 1820 1821 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1822 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1823 return NULL; 1824 } 1825 1826 #ifndef S390 1827 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1828 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1829 return NULL; 1830 } 1831 #endif // !S390 1832 1833 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1834 if (lib_arch.name!=NULL) { 1835 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1836 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1837 lib_arch.name, arch_array[running_arch_index].name); 1838 } else { 1839 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1840 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1841 lib_arch.code, 1842 arch_array[running_arch_index].name); 1843 } 1844 } 1845 1846 return NULL; 1847 } 1848 1849 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1850 int ebuflen) { 1851 void * result = ::dlopen(filename, RTLD_LAZY); 1852 if (result == NULL) { 1853 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1854 ebuf[ebuflen-1] = '\0'; 1855 } 1856 return result; 1857 } 1858 1859 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1860 int ebuflen) { 1861 void * result = NULL; 1862 if (LoadExecStackDllInVMThread) { 1863 result = dlopen_helper(filename, ebuf, ebuflen); 1864 } 1865 1866 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1867 // library that requires an executable stack, or which does not have this 1868 // stack attribute set, dlopen changes the stack attribute to executable. The 1869 // read protection of the guard pages gets lost. 1870 // 1871 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1872 // may have been queued at the same time. 1873 1874 if (!_stack_is_executable) { 1875 JavaThread *jt = Threads::first(); 1876 1877 while (jt) { 1878 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1879 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1880 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1881 warning("Attempt to reguard stack yellow zone failed."); 1882 } 1883 } 1884 jt = jt->next(); 1885 } 1886 } 1887 1888 return result; 1889 } 1890 1891 void* os::dll_lookup(void* handle, const char* name) { 1892 void* res = dlsym(handle, name); 1893 return res; 1894 } 1895 1896 void* os::get_default_process_handle() { 1897 return (void*)::dlopen(NULL, RTLD_LAZY); 1898 } 1899 1900 static bool _print_ascii_file(const char* filename, outputStream* st) { 1901 int fd = ::open(filename, O_RDONLY); 1902 if (fd == -1) { 1903 return false; 1904 } 1905 1906 char buf[33]; 1907 int bytes; 1908 buf[32] = '\0'; 1909 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1910 st->print_raw(buf, bytes); 1911 } 1912 1913 ::close(fd); 1914 1915 return true; 1916 } 1917 1918 void os::print_dll_info(outputStream *st) { 1919 st->print_cr("Dynamic libraries:"); 1920 1921 char fname[32]; 1922 pid_t pid = os::Linux::gettid(); 1923 1924 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1925 1926 if (!_print_ascii_file(fname, st)) { 1927 st->print("Can not get library information for pid = %d\n", pid); 1928 } 1929 } 1930 1931 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1932 FILE *procmapsFile = NULL; 1933 1934 // Open the procfs maps file for the current process 1935 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1936 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1937 char line[PATH_MAX + 100]; 1938 1939 // Read line by line from 'file' 1940 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1941 u8 base, top, offset, inode; 1942 char permissions[5]; 1943 char device[6]; 1944 char name[PATH_MAX + 1]; 1945 1946 // Parse fields from line 1947 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1948 &base, &top, permissions, &offset, device, &inode, name); 1949 1950 // Filter by device id '00:00' so that we only get file system mapped files. 1951 if (strcmp(device, "00:00") != 0) { 1952 1953 // Call callback with the fields of interest 1954 if(callback(name, (address)base, (address)top, param)) { 1955 // Oops abort, callback aborted 1956 fclose(procmapsFile); 1957 return 1; 1958 } 1959 } 1960 } 1961 fclose(procmapsFile); 1962 } 1963 return 0; 1964 } 1965 1966 void os::print_os_info_brief(outputStream* st) { 1967 os::Linux::print_distro_info(st); 1968 1969 os::Posix::print_uname_info(st); 1970 1971 os::Linux::print_libversion_info(st); 1972 1973 } 1974 1975 void os::print_os_info(outputStream* st) { 1976 st->print("OS:"); 1977 1978 os::Linux::print_distro_info(st); 1979 1980 os::Posix::print_uname_info(st); 1981 1982 // Print warning if unsafe chroot environment detected 1983 if (unsafe_chroot_detected) { 1984 st->print("WARNING!! "); 1985 st->print_cr("%s", unstable_chroot_error); 1986 } 1987 1988 os::Linux::print_libversion_info(st); 1989 1990 os::Posix::print_rlimit_info(st); 1991 1992 os::Posix::print_load_average(st); 1993 1994 os::Linux::print_full_memory_info(st); 1995 } 1996 1997 // Try to identify popular distros. 1998 // Most Linux distributions have a /etc/XXX-release file, which contains 1999 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2000 // file that also contains the OS version string. Some have more than one 2001 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2002 // /etc/redhat-release.), so the order is important. 2003 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2004 // their own specific XXX-release file as well as a redhat-release file. 2005 // Because of this the XXX-release file needs to be searched for before the 2006 // redhat-release file. 2007 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2008 // search for redhat-release / SuSE-release needs to be before lsb-release. 2009 // Since the lsb-release file is the new standard it needs to be searched 2010 // before the older style release files. 2011 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2012 // next to last resort. The os-release file is a new standard that contains 2013 // distribution information and the system-release file seems to be an old 2014 // standard that has been replaced by the lsb-release and os-release files. 2015 // Searching for the debian_version file is the last resort. It contains 2016 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2017 // "Debian " is printed before the contents of the debian_version file. 2018 2019 const char* distro_files[] = { 2020 "/etc/oracle-release", 2021 "/etc/mandriva-release", 2022 "/etc/mandrake-release", 2023 "/etc/sun-release", 2024 "/etc/redhat-release", 2025 "/etc/SuSE-release", 2026 "/etc/lsb-release", 2027 "/etc/turbolinux-release", 2028 "/etc/gentoo-release", 2029 "/etc/ltib-release", 2030 "/etc/angstrom-version", 2031 "/etc/system-release", 2032 "/etc/os-release", 2033 NULL }; 2034 2035 void os::Linux::print_distro_info(outputStream* st) { 2036 for (int i = 0;; i++) { 2037 const char* file = distro_files[i]; 2038 if (file == NULL) { 2039 break; // done 2040 } 2041 // If file prints, we found it. 2042 if (_print_ascii_file(file, st)) { 2043 return; 2044 } 2045 } 2046 2047 if (file_exists("/etc/debian_version")) { 2048 st->print("Debian "); 2049 _print_ascii_file("/etc/debian_version", st); 2050 } else { 2051 st->print("Linux"); 2052 } 2053 st->cr(); 2054 } 2055 2056 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2057 char buf[256]; 2058 while (fgets(buf, sizeof(buf), fp)) { 2059 // Edit out extra stuff in expected format 2060 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2061 char* ptr = strstr(buf, "\""); // the name is in quotes 2062 if (ptr != NULL) { 2063 ptr++; // go beyond first quote 2064 char* nl = strchr(ptr, '\"'); 2065 if (nl != NULL) *nl = '\0'; 2066 strncpy(distro, ptr, length); 2067 } else { 2068 ptr = strstr(buf, "="); 2069 ptr++; // go beyond equals then 2070 char* nl = strchr(ptr, '\n'); 2071 if (nl != NULL) *nl = '\0'; 2072 strncpy(distro, ptr, length); 2073 } 2074 return; 2075 } else if (get_first_line) { 2076 char* nl = strchr(buf, '\n'); 2077 if (nl != NULL) *nl = '\0'; 2078 strncpy(distro, buf, length); 2079 return; 2080 } 2081 } 2082 // print last line and close 2083 char* nl = strchr(buf, '\n'); 2084 if (nl != NULL) *nl = '\0'; 2085 strncpy(distro, buf, length); 2086 } 2087 2088 static void parse_os_info(char* distro, size_t length, const char* file) { 2089 FILE* fp = fopen(file, "r"); 2090 if (fp != NULL) { 2091 // if suse format, print out first line 2092 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2093 parse_os_info_helper(fp, distro, length, get_first_line); 2094 fclose(fp); 2095 } 2096 } 2097 2098 void os::get_summary_os_info(char* buf, size_t buflen) { 2099 for (int i = 0;; i++) { 2100 const char* file = distro_files[i]; 2101 if (file == NULL) { 2102 break; // ran out of distro_files 2103 } 2104 if (file_exists(file)) { 2105 parse_os_info(buf, buflen, file); 2106 return; 2107 } 2108 } 2109 // special case for debian 2110 if (file_exists("/etc/debian_version")) { 2111 strncpy(buf, "Debian ", buflen); 2112 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2113 } else { 2114 strncpy(buf, "Linux", buflen); 2115 } 2116 } 2117 2118 void os::Linux::print_libversion_info(outputStream* st) { 2119 // libc, pthread 2120 st->print("libc:"); 2121 st->print("%s ", os::Linux::glibc_version()); 2122 st->print("%s ", os::Linux::libpthread_version()); 2123 st->cr(); 2124 } 2125 2126 void os::Linux::print_full_memory_info(outputStream* st) { 2127 st->print("\n/proc/meminfo:\n"); 2128 _print_ascii_file("/proc/meminfo", st); 2129 st->cr(); 2130 } 2131 2132 void os::print_memory_info(outputStream* st) { 2133 2134 st->print("Memory:"); 2135 st->print(" %dk page", os::vm_page_size()>>10); 2136 2137 // values in struct sysinfo are "unsigned long" 2138 struct sysinfo si; 2139 sysinfo(&si); 2140 2141 st->print(", physical " UINT64_FORMAT "k", 2142 os::physical_memory() >> 10); 2143 st->print("(" UINT64_FORMAT "k free)", 2144 os::available_memory() >> 10); 2145 st->print(", swap " UINT64_FORMAT "k", 2146 ((jlong)si.totalswap * si.mem_unit) >> 10); 2147 st->print("(" UINT64_FORMAT "k free)", 2148 ((jlong)si.freeswap * si.mem_unit) >> 10); 2149 st->cr(); 2150 } 2151 2152 // Print the first "model name" line and the first "flags" line 2153 // that we find and nothing more. We assume "model name" comes 2154 // before "flags" so if we find a second "model name", then the 2155 // "flags" field is considered missing. 2156 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2157 #if defined(IA32) || defined(AMD64) 2158 // Other platforms have less repetitive cpuinfo files 2159 FILE *fp = fopen("/proc/cpuinfo", "r"); 2160 if (fp) { 2161 while (!feof(fp)) { 2162 if (fgets(buf, buflen, fp)) { 2163 // Assume model name comes before flags 2164 bool model_name_printed = false; 2165 if (strstr(buf, "model name") != NULL) { 2166 if (!model_name_printed) { 2167 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2168 st->print_raw(buf); 2169 model_name_printed = true; 2170 } else { 2171 // model name printed but not flags? Odd, just return 2172 fclose(fp); 2173 return true; 2174 } 2175 } 2176 // print the flags line too 2177 if (strstr(buf, "flags") != NULL) { 2178 st->print_raw(buf); 2179 fclose(fp); 2180 return true; 2181 } 2182 } 2183 } 2184 fclose(fp); 2185 } 2186 #endif // x86 platforms 2187 return false; 2188 } 2189 2190 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2191 // Only print the model name if the platform provides this as a summary 2192 if (!print_model_name_and_flags(st, buf, buflen)) { 2193 st->print("\n/proc/cpuinfo:\n"); 2194 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2195 st->print_cr(" <Not Available>"); 2196 } 2197 } 2198 } 2199 2200 #if defined(AMD64) || defined(IA32) || defined(X32) 2201 const char* search_string = "model name"; 2202 #elif defined(PPC64) 2203 const char* search_string = "cpu"; 2204 #elif defined(S390) 2205 const char* search_string = "processor"; 2206 #elif defined(SPARC) 2207 const char* search_string = "cpu"; 2208 #else 2209 const char* search_string = "Processor"; 2210 #endif 2211 2212 // Parses the cpuinfo file for string representing the model name. 2213 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2214 FILE* fp = fopen("/proc/cpuinfo", "r"); 2215 if (fp != NULL) { 2216 while (!feof(fp)) { 2217 char buf[256]; 2218 if (fgets(buf, sizeof(buf), fp)) { 2219 char* start = strstr(buf, search_string); 2220 if (start != NULL) { 2221 char *ptr = start + strlen(search_string); 2222 char *end = buf + strlen(buf); 2223 while (ptr != end) { 2224 // skip whitespace and colon for the rest of the name. 2225 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2226 break; 2227 } 2228 ptr++; 2229 } 2230 if (ptr != end) { 2231 // reasonable string, get rid of newline and keep the rest 2232 char* nl = strchr(buf, '\n'); 2233 if (nl != NULL) *nl = '\0'; 2234 strncpy(cpuinfo, ptr, length); 2235 fclose(fp); 2236 return; 2237 } 2238 } 2239 } 2240 } 2241 fclose(fp); 2242 } 2243 // cpuinfo not found or parsing failed, just print generic string. The entire 2244 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2245 #if defined(AARCH64) 2246 strncpy(cpuinfo, "AArch64", length); 2247 #elif defined(AMD64) 2248 strncpy(cpuinfo, "x86_64", length); 2249 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2250 strncpy(cpuinfo, "ARM", length); 2251 #elif defined(IA32) 2252 strncpy(cpuinfo, "x86_32", length); 2253 #elif defined(IA64) 2254 strncpy(cpuinfo, "IA64", length); 2255 #elif defined(PPC) 2256 strncpy(cpuinfo, "PPC64", length); 2257 #elif defined(S390) 2258 strncpy(cpuinfo, "S390", length); 2259 #elif defined(SPARC) 2260 strncpy(cpuinfo, "sparcv9", length); 2261 #elif defined(ZERO_LIBARCH) 2262 strncpy(cpuinfo, ZERO_LIBARCH, length); 2263 #else 2264 strncpy(cpuinfo, "unknown", length); 2265 #endif 2266 } 2267 2268 static void print_signal_handler(outputStream* st, int sig, 2269 char* buf, size_t buflen); 2270 2271 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2272 st->print_cr("Signal Handlers:"); 2273 print_signal_handler(st, SIGSEGV, buf, buflen); 2274 print_signal_handler(st, SIGBUS , buf, buflen); 2275 print_signal_handler(st, SIGFPE , buf, buflen); 2276 print_signal_handler(st, SIGPIPE, buf, buflen); 2277 print_signal_handler(st, SIGXFSZ, buf, buflen); 2278 print_signal_handler(st, SIGILL , buf, buflen); 2279 print_signal_handler(st, SR_signum, buf, buflen); 2280 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2281 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2282 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2283 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2284 #if defined(PPC64) 2285 print_signal_handler(st, SIGTRAP, buf, buflen); 2286 #endif 2287 } 2288 2289 static char saved_jvm_path[MAXPATHLEN] = {0}; 2290 2291 // Find the full path to the current module, libjvm.so 2292 void os::jvm_path(char *buf, jint buflen) { 2293 // Error checking. 2294 if (buflen < MAXPATHLEN) { 2295 assert(false, "must use a large-enough buffer"); 2296 buf[0] = '\0'; 2297 return; 2298 } 2299 // Lazy resolve the path to current module. 2300 if (saved_jvm_path[0] != 0) { 2301 strcpy(buf, saved_jvm_path); 2302 return; 2303 } 2304 2305 char dli_fname[MAXPATHLEN]; 2306 bool ret = dll_address_to_library_name( 2307 CAST_FROM_FN_PTR(address, os::jvm_path), 2308 dli_fname, sizeof(dli_fname), NULL); 2309 assert(ret, "cannot locate libjvm"); 2310 char *rp = NULL; 2311 if (ret && dli_fname[0] != '\0') { 2312 rp = realpath(dli_fname, buf); 2313 } 2314 if (rp == NULL) { 2315 return; 2316 } 2317 2318 if (Arguments::sun_java_launcher_is_altjvm()) { 2319 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2320 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2321 // If "/jre/lib/" appears at the right place in the string, then 2322 // assume we are installed in a JDK and we're done. Otherwise, check 2323 // for a JAVA_HOME environment variable and fix up the path so it 2324 // looks like libjvm.so is installed there (append a fake suffix 2325 // hotspot/libjvm.so). 2326 const char *p = buf + strlen(buf) - 1; 2327 for (int count = 0; p > buf && count < 5; ++count) { 2328 for (--p; p > buf && *p != '/'; --p) 2329 /* empty */ ; 2330 } 2331 2332 if (strncmp(p, "/jre/lib/", 9) != 0) { 2333 // Look for JAVA_HOME in the environment. 2334 char* java_home_var = ::getenv("JAVA_HOME"); 2335 if (java_home_var != NULL && java_home_var[0] != 0) { 2336 char* jrelib_p; 2337 int len; 2338 2339 // Check the current module name "libjvm.so". 2340 p = strrchr(buf, '/'); 2341 if (p == NULL) { 2342 return; 2343 } 2344 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2345 2346 rp = realpath(java_home_var, buf); 2347 if (rp == NULL) { 2348 return; 2349 } 2350 2351 // determine if this is a legacy image or modules image 2352 // modules image doesn't have "jre" subdirectory 2353 len = strlen(buf); 2354 assert(len < buflen, "Ran out of buffer room"); 2355 jrelib_p = buf + len; 2356 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2357 if (0 != access(buf, F_OK)) { 2358 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2359 } 2360 2361 if (0 == access(buf, F_OK)) { 2362 // Use current module name "libjvm.so" 2363 len = strlen(buf); 2364 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2365 } else { 2366 // Go back to path of .so 2367 rp = realpath(dli_fname, buf); 2368 if (rp == NULL) { 2369 return; 2370 } 2371 } 2372 } 2373 } 2374 } 2375 2376 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2377 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2378 } 2379 2380 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2381 // no prefix required, not even "_" 2382 } 2383 2384 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2385 // no suffix required 2386 } 2387 2388 //////////////////////////////////////////////////////////////////////////////// 2389 // sun.misc.Signal support 2390 2391 static volatile jint sigint_count = 0; 2392 2393 static void UserHandler(int sig, void *siginfo, void *context) { 2394 // 4511530 - sem_post is serialized and handled by the manager thread. When 2395 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2396 // don't want to flood the manager thread with sem_post requests. 2397 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2398 return; 2399 } 2400 2401 // Ctrl-C is pressed during error reporting, likely because the error 2402 // handler fails to abort. Let VM die immediately. 2403 if (sig == SIGINT && is_error_reported()) { 2404 os::die(); 2405 } 2406 2407 os::signal_notify(sig); 2408 } 2409 2410 void* os::user_handler() { 2411 return CAST_FROM_FN_PTR(void*, UserHandler); 2412 } 2413 2414 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2415 struct timespec ts; 2416 // Semaphore's are always associated with CLOCK_REALTIME 2417 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2418 // see unpackTime for discussion on overflow checking 2419 if (sec >= MAX_SECS) { 2420 ts.tv_sec += MAX_SECS; 2421 ts.tv_nsec = 0; 2422 } else { 2423 ts.tv_sec += sec; 2424 ts.tv_nsec += nsec; 2425 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2426 ts.tv_nsec -= NANOSECS_PER_SEC; 2427 ++ts.tv_sec; // note: this must be <= max_secs 2428 } 2429 } 2430 2431 return ts; 2432 } 2433 2434 extern "C" { 2435 typedef void (*sa_handler_t)(int); 2436 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2437 } 2438 2439 void* os::signal(int signal_number, void* handler) { 2440 struct sigaction sigAct, oldSigAct; 2441 2442 sigfillset(&(sigAct.sa_mask)); 2443 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2444 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2445 2446 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2447 // -1 means registration failed 2448 return (void *)-1; 2449 } 2450 2451 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2452 } 2453 2454 void os::signal_raise(int signal_number) { 2455 ::raise(signal_number); 2456 } 2457 2458 // The following code is moved from os.cpp for making this 2459 // code platform specific, which it is by its very nature. 2460 2461 // Will be modified when max signal is changed to be dynamic 2462 int os::sigexitnum_pd() { 2463 return NSIG; 2464 } 2465 2466 // a counter for each possible signal value 2467 static volatile jint pending_signals[NSIG+1] = { 0 }; 2468 2469 // Linux(POSIX) specific hand shaking semaphore. 2470 static sem_t sig_sem; 2471 static PosixSemaphore sr_semaphore; 2472 2473 void os::signal_init_pd() { 2474 // Initialize signal structures 2475 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2476 2477 // Initialize signal semaphore 2478 ::sem_init(&sig_sem, 0, 0); 2479 } 2480 2481 void os::signal_notify(int sig) { 2482 Atomic::inc(&pending_signals[sig]); 2483 ::sem_post(&sig_sem); 2484 } 2485 2486 static int check_pending_signals(bool wait) { 2487 Atomic::store(0, &sigint_count); 2488 for (;;) { 2489 for (int i = 0; i < NSIG + 1; i++) { 2490 jint n = pending_signals[i]; 2491 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2492 return i; 2493 } 2494 } 2495 if (!wait) { 2496 return -1; 2497 } 2498 JavaThread *thread = JavaThread::current(); 2499 ThreadBlockInVM tbivm(thread); 2500 2501 bool threadIsSuspended; 2502 do { 2503 thread->set_suspend_equivalent(); 2504 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2505 ::sem_wait(&sig_sem); 2506 2507 // were we externally suspended while we were waiting? 2508 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2509 if (threadIsSuspended) { 2510 // The semaphore has been incremented, but while we were waiting 2511 // another thread suspended us. We don't want to continue running 2512 // while suspended because that would surprise the thread that 2513 // suspended us. 2514 ::sem_post(&sig_sem); 2515 2516 thread->java_suspend_self(); 2517 } 2518 } while (threadIsSuspended); 2519 } 2520 } 2521 2522 int os::signal_lookup() { 2523 return check_pending_signals(false); 2524 } 2525 2526 int os::signal_wait() { 2527 return check_pending_signals(true); 2528 } 2529 2530 //////////////////////////////////////////////////////////////////////////////// 2531 // Virtual Memory 2532 2533 int os::vm_page_size() { 2534 // Seems redundant as all get out 2535 assert(os::Linux::page_size() != -1, "must call os::init"); 2536 return os::Linux::page_size(); 2537 } 2538 2539 // Solaris allocates memory by pages. 2540 int os::vm_allocation_granularity() { 2541 assert(os::Linux::page_size() != -1, "must call os::init"); 2542 return os::Linux::page_size(); 2543 } 2544 2545 // Rationale behind this function: 2546 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2547 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2548 // samples for JITted code. Here we create private executable mapping over the code cache 2549 // and then we can use standard (well, almost, as mapping can change) way to provide 2550 // info for the reporting script by storing timestamp and location of symbol 2551 void linux_wrap_code(char* base, size_t size) { 2552 static volatile jint cnt = 0; 2553 2554 if (!UseOprofile) { 2555 return; 2556 } 2557 2558 char buf[PATH_MAX+1]; 2559 int num = Atomic::add(1, &cnt); 2560 2561 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2562 os::get_temp_directory(), os::current_process_id(), num); 2563 unlink(buf); 2564 2565 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2566 2567 if (fd != -1) { 2568 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2569 if (rv != (off_t)-1) { 2570 if (::write(fd, "", 1) == 1) { 2571 mmap(base, size, 2572 PROT_READ|PROT_WRITE|PROT_EXEC, 2573 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2574 } 2575 } 2576 ::close(fd); 2577 unlink(buf); 2578 } 2579 } 2580 2581 static bool recoverable_mmap_error(int err) { 2582 // See if the error is one we can let the caller handle. This 2583 // list of errno values comes from JBS-6843484. I can't find a 2584 // Linux man page that documents this specific set of errno 2585 // values so while this list currently matches Solaris, it may 2586 // change as we gain experience with this failure mode. 2587 switch (err) { 2588 case EBADF: 2589 case EINVAL: 2590 case ENOTSUP: 2591 // let the caller deal with these errors 2592 return true; 2593 2594 default: 2595 // Any remaining errors on this OS can cause our reserved mapping 2596 // to be lost. That can cause confusion where different data 2597 // structures think they have the same memory mapped. The worst 2598 // scenario is if both the VM and a library think they have the 2599 // same memory mapped. 2600 return false; 2601 } 2602 } 2603 2604 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2605 int err) { 2606 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2607 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2608 os::strerror(err), err); 2609 } 2610 2611 static void warn_fail_commit_memory(char* addr, size_t size, 2612 size_t alignment_hint, bool exec, 2613 int err) { 2614 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2615 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2616 alignment_hint, exec, os::strerror(err), err); 2617 } 2618 2619 // NOTE: Linux kernel does not really reserve the pages for us. 2620 // All it does is to check if there are enough free pages 2621 // left at the time of mmap(). This could be a potential 2622 // problem. 2623 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2624 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2625 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2626 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2627 if (res != (uintptr_t) MAP_FAILED) { 2628 if (UseNUMAInterleaving) { 2629 numa_make_global(addr, size); 2630 } 2631 return 0; 2632 } 2633 2634 int err = errno; // save errno from mmap() call above 2635 2636 if (!recoverable_mmap_error(err)) { 2637 warn_fail_commit_memory(addr, size, exec, err); 2638 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2639 } 2640 2641 return err; 2642 } 2643 2644 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2645 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2646 } 2647 2648 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2649 const char* mesg) { 2650 assert(mesg != NULL, "mesg must be specified"); 2651 int err = os::Linux::commit_memory_impl(addr, size, exec); 2652 if (err != 0) { 2653 // the caller wants all commit errors to exit with the specified mesg: 2654 warn_fail_commit_memory(addr, size, exec, err); 2655 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2656 } 2657 } 2658 2659 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2660 #ifndef MAP_HUGETLB 2661 #define MAP_HUGETLB 0x40000 2662 #endif 2663 2664 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2665 #ifndef MADV_HUGEPAGE 2666 #define MADV_HUGEPAGE 14 2667 #endif 2668 2669 int os::Linux::commit_memory_impl(char* addr, size_t size, 2670 size_t alignment_hint, bool exec) { 2671 int err = os::Linux::commit_memory_impl(addr, size, exec); 2672 if (err == 0) { 2673 realign_memory(addr, size, alignment_hint); 2674 } 2675 return err; 2676 } 2677 2678 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2679 bool exec) { 2680 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2681 } 2682 2683 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2684 size_t alignment_hint, bool exec, 2685 const char* mesg) { 2686 assert(mesg != NULL, "mesg must be specified"); 2687 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2688 if (err != 0) { 2689 // the caller wants all commit errors to exit with the specified mesg: 2690 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2691 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2692 } 2693 } 2694 2695 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2696 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2697 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2698 // be supported or the memory may already be backed by huge pages. 2699 ::madvise(addr, bytes, MADV_HUGEPAGE); 2700 } 2701 } 2702 2703 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2704 // This method works by doing an mmap over an existing mmaping and effectively discarding 2705 // the existing pages. However it won't work for SHM-based large pages that cannot be 2706 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2707 // small pages on top of the SHM segment. This method always works for small pages, so we 2708 // allow that in any case. 2709 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2710 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2711 } 2712 } 2713 2714 void os::numa_make_global(char *addr, size_t bytes) { 2715 Linux::numa_interleave_memory(addr, bytes); 2716 } 2717 2718 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2719 // bind policy to MPOL_PREFERRED for the current thread. 2720 #define USE_MPOL_PREFERRED 0 2721 2722 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2723 // To make NUMA and large pages more robust when both enabled, we need to ease 2724 // the requirements on where the memory should be allocated. MPOL_BIND is the 2725 // default policy and it will force memory to be allocated on the specified 2726 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2727 // the specified node, but will not force it. Using this policy will prevent 2728 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2729 // free large pages. 2730 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2731 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2732 } 2733 2734 bool os::numa_topology_changed() { return false; } 2735 2736 size_t os::numa_get_groups_num() { 2737 int max_node = Linux::numa_max_node(); 2738 return max_node > 0 ? max_node + 1 : 1; 2739 } 2740 2741 int os::numa_get_group_id() { 2742 int cpu_id = Linux::sched_getcpu(); 2743 if (cpu_id != -1) { 2744 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2745 if (lgrp_id != -1) { 2746 return lgrp_id; 2747 } 2748 } 2749 return 0; 2750 } 2751 2752 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2753 for (size_t i = 0; i < size; i++) { 2754 ids[i] = i; 2755 } 2756 return size; 2757 } 2758 2759 bool os::get_page_info(char *start, page_info* info) { 2760 return false; 2761 } 2762 2763 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2764 page_info* page_found) { 2765 return end; 2766 } 2767 2768 2769 int os::Linux::sched_getcpu_syscall(void) { 2770 unsigned int cpu = 0; 2771 int retval = -1; 2772 2773 #if defined(IA32) 2774 #ifndef SYS_getcpu 2775 #define SYS_getcpu 318 2776 #endif 2777 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2778 #elif defined(AMD64) 2779 // Unfortunately we have to bring all these macros here from vsyscall.h 2780 // to be able to compile on old linuxes. 2781 #define __NR_vgetcpu 2 2782 #define VSYSCALL_START (-10UL << 20) 2783 #define VSYSCALL_SIZE 1024 2784 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2785 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2786 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2787 retval = vgetcpu(&cpu, NULL, NULL); 2788 #endif 2789 2790 return (retval == -1) ? retval : cpu; 2791 } 2792 2793 // Something to do with the numa-aware allocator needs these symbols 2794 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2795 extern "C" JNIEXPORT void numa_error(char *where) { } 2796 2797 2798 // If we are running with libnuma version > 2, then we should 2799 // be trying to use symbols with versions 1.1 2800 // If we are running with earlier version, which did not have symbol versions, 2801 // we should use the base version. 2802 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2803 void *f = dlvsym(handle, name, "libnuma_1.1"); 2804 if (f == NULL) { 2805 f = dlsym(handle, name); 2806 } 2807 return f; 2808 } 2809 2810 bool os::Linux::libnuma_init() { 2811 // sched_getcpu() should be in libc. 2812 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2813 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2814 2815 // If it's not, try a direct syscall. 2816 if (sched_getcpu() == -1) { 2817 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2818 (void*)&sched_getcpu_syscall)); 2819 } 2820 2821 if (sched_getcpu() != -1) { // Does it work? 2822 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2823 if (handle != NULL) { 2824 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2825 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2826 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2827 libnuma_dlsym(handle, "numa_max_node"))); 2828 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2829 libnuma_dlsym(handle, "numa_available"))); 2830 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2831 libnuma_dlsym(handle, "numa_tonode_memory"))); 2832 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2833 libnuma_dlsym(handle, "numa_interleave_memory"))); 2834 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2835 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2836 2837 2838 if (numa_available() != -1) { 2839 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2840 // Create a cpu -> node mapping 2841 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2842 rebuild_cpu_to_node_map(); 2843 return true; 2844 } 2845 } 2846 } 2847 return false; 2848 } 2849 2850 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 2851 // Creating guard page is very expensive. Java thread has HotSpot 2852 // guard pages, only enable glibc guard page for non-Java threads. 2853 // (Remember: compiler thread is a Java thread, too!) 2854 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 2855 } 2856 2857 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2858 // The table is later used in get_node_by_cpu(). 2859 void os::Linux::rebuild_cpu_to_node_map() { 2860 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2861 // in libnuma (possible values are starting from 16, 2862 // and continuing up with every other power of 2, but less 2863 // than the maximum number of CPUs supported by kernel), and 2864 // is a subject to change (in libnuma version 2 the requirements 2865 // are more reasonable) we'll just hardcode the number they use 2866 // in the library. 2867 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2868 2869 size_t cpu_num = processor_count(); 2870 size_t cpu_map_size = NCPUS / BitsPerCLong; 2871 size_t cpu_map_valid_size = 2872 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2873 2874 cpu_to_node()->clear(); 2875 cpu_to_node()->at_grow(cpu_num - 1); 2876 size_t node_num = numa_get_groups_num(); 2877 2878 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2879 for (size_t i = 0; i < node_num; i++) { 2880 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2881 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2882 if (cpu_map[j] != 0) { 2883 for (size_t k = 0; k < BitsPerCLong; k++) { 2884 if (cpu_map[j] & (1UL << k)) { 2885 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2886 } 2887 } 2888 } 2889 } 2890 } 2891 } 2892 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2893 } 2894 2895 int os::Linux::get_node_by_cpu(int cpu_id) { 2896 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2897 return cpu_to_node()->at(cpu_id); 2898 } 2899 return -1; 2900 } 2901 2902 GrowableArray<int>* os::Linux::_cpu_to_node; 2903 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2904 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2905 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2906 os::Linux::numa_available_func_t os::Linux::_numa_available; 2907 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2908 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2909 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2910 unsigned long* os::Linux::_numa_all_nodes; 2911 2912 bool os::pd_uncommit_memory(char* addr, size_t size) { 2913 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2914 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2915 return res != (uintptr_t) MAP_FAILED; 2916 } 2917 2918 static address get_stack_commited_bottom(address bottom, size_t size) { 2919 address nbot = bottom; 2920 address ntop = bottom + size; 2921 2922 size_t page_sz = os::vm_page_size(); 2923 unsigned pages = size / page_sz; 2924 2925 unsigned char vec[1]; 2926 unsigned imin = 1, imax = pages + 1, imid; 2927 int mincore_return_value = 0; 2928 2929 assert(imin <= imax, "Unexpected page size"); 2930 2931 while (imin < imax) { 2932 imid = (imax + imin) / 2; 2933 nbot = ntop - (imid * page_sz); 2934 2935 // Use a trick with mincore to check whether the page is mapped or not. 2936 // mincore sets vec to 1 if page resides in memory and to 0 if page 2937 // is swapped output but if page we are asking for is unmapped 2938 // it returns -1,ENOMEM 2939 mincore_return_value = mincore(nbot, page_sz, vec); 2940 2941 if (mincore_return_value == -1) { 2942 // Page is not mapped go up 2943 // to find first mapped page 2944 if (errno != EAGAIN) { 2945 assert(errno == ENOMEM, "Unexpected mincore errno"); 2946 imax = imid; 2947 } 2948 } else { 2949 // Page is mapped go down 2950 // to find first not mapped page 2951 imin = imid + 1; 2952 } 2953 } 2954 2955 nbot = nbot + page_sz; 2956 2957 // Adjust stack bottom one page up if last checked page is not mapped 2958 if (mincore_return_value == -1) { 2959 nbot = nbot + page_sz; 2960 } 2961 2962 return nbot; 2963 } 2964 2965 2966 // Linux uses a growable mapping for the stack, and if the mapping for 2967 // the stack guard pages is not removed when we detach a thread the 2968 // stack cannot grow beyond the pages where the stack guard was 2969 // mapped. If at some point later in the process the stack expands to 2970 // that point, the Linux kernel cannot expand the stack any further 2971 // because the guard pages are in the way, and a segfault occurs. 2972 // 2973 // However, it's essential not to split the stack region by unmapping 2974 // a region (leaving a hole) that's already part of the stack mapping, 2975 // so if the stack mapping has already grown beyond the guard pages at 2976 // the time we create them, we have to truncate the stack mapping. 2977 // So, we need to know the extent of the stack mapping when 2978 // create_stack_guard_pages() is called. 2979 2980 // We only need this for stacks that are growable: at the time of 2981 // writing thread stacks don't use growable mappings (i.e. those 2982 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2983 // only applies to the main thread. 2984 2985 // If the (growable) stack mapping already extends beyond the point 2986 // where we're going to put our guard pages, truncate the mapping at 2987 // that point by munmap()ping it. This ensures that when we later 2988 // munmap() the guard pages we don't leave a hole in the stack 2989 // mapping. This only affects the main/initial thread 2990 2991 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2992 if (os::Linux::is_initial_thread()) { 2993 // As we manually grow stack up to bottom inside create_attached_thread(), 2994 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 2995 // we don't need to do anything special. 2996 // Check it first, before calling heavy function. 2997 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 2998 unsigned char vec[1]; 2999 3000 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3001 // Fallback to slow path on all errors, including EAGAIN 3002 stack_extent = (uintptr_t) get_stack_commited_bottom( 3003 os::Linux::initial_thread_stack_bottom(), 3004 (size_t)addr - stack_extent); 3005 } 3006 3007 if (stack_extent < (uintptr_t)addr) { 3008 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3009 } 3010 } 3011 3012 return os::commit_memory(addr, size, !ExecMem); 3013 } 3014 3015 // If this is a growable mapping, remove the guard pages entirely by 3016 // munmap()ping them. If not, just call uncommit_memory(). This only 3017 // affects the main/initial thread, but guard against future OS changes 3018 // It's safe to always unmap guard pages for initial thread because we 3019 // always place it right after end of the mapped region 3020 3021 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3022 uintptr_t stack_extent, stack_base; 3023 3024 if (os::Linux::is_initial_thread()) { 3025 return ::munmap(addr, size) == 0; 3026 } 3027 3028 return os::uncommit_memory(addr, size); 3029 } 3030 3031 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3032 // at 'requested_addr'. If there are existing memory mappings at the same 3033 // location, however, they will be overwritten. If 'fixed' is false, 3034 // 'requested_addr' is only treated as a hint, the return value may or 3035 // may not start from the requested address. Unlike Linux mmap(), this 3036 // function returns NULL to indicate failure. 3037 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3038 char * addr; 3039 int flags; 3040 3041 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3042 if (fixed) { 3043 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3044 flags |= MAP_FIXED; 3045 } 3046 3047 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3048 // touch an uncommitted page. Otherwise, the read/write might 3049 // succeed if we have enough swap space to back the physical page. 3050 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3051 flags, -1, 0); 3052 3053 return addr == MAP_FAILED ? NULL : addr; 3054 } 3055 3056 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3057 // (req_addr != NULL) or with a given alignment. 3058 // - bytes shall be a multiple of alignment. 3059 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3060 // - alignment sets the alignment at which memory shall be allocated. 3061 // It must be a multiple of allocation granularity. 3062 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3063 // req_addr or NULL. 3064 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3065 3066 size_t extra_size = bytes; 3067 if (req_addr == NULL && alignment > 0) { 3068 extra_size += alignment; 3069 } 3070 3071 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3072 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3073 -1, 0); 3074 if (start == MAP_FAILED) { 3075 start = NULL; 3076 } else { 3077 if (req_addr != NULL) { 3078 if (start != req_addr) { 3079 ::munmap(start, extra_size); 3080 start = NULL; 3081 } 3082 } else { 3083 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3084 char* const end_aligned = start_aligned + bytes; 3085 char* const end = start + extra_size; 3086 if (start_aligned > start) { 3087 ::munmap(start, start_aligned - start); 3088 } 3089 if (end_aligned < end) { 3090 ::munmap(end_aligned, end - end_aligned); 3091 } 3092 start = start_aligned; 3093 } 3094 } 3095 return start; 3096 } 3097 3098 static int anon_munmap(char * addr, size_t size) { 3099 return ::munmap(addr, size) == 0; 3100 } 3101 3102 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3103 size_t alignment_hint) { 3104 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3105 } 3106 3107 bool os::pd_release_memory(char* addr, size_t size) { 3108 return anon_munmap(addr, size); 3109 } 3110 3111 static bool linux_mprotect(char* addr, size_t size, int prot) { 3112 // Linux wants the mprotect address argument to be page aligned. 3113 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3114 3115 // According to SUSv3, mprotect() should only be used with mappings 3116 // established by mmap(), and mmap() always maps whole pages. Unaligned 3117 // 'addr' likely indicates problem in the VM (e.g. trying to change 3118 // protection of malloc'ed or statically allocated memory). Check the 3119 // caller if you hit this assert. 3120 assert(addr == bottom, "sanity check"); 3121 3122 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3123 return ::mprotect(bottom, size, prot) == 0; 3124 } 3125 3126 // Set protections specified 3127 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3128 bool is_committed) { 3129 unsigned int p = 0; 3130 switch (prot) { 3131 case MEM_PROT_NONE: p = PROT_NONE; break; 3132 case MEM_PROT_READ: p = PROT_READ; break; 3133 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3134 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3135 default: 3136 ShouldNotReachHere(); 3137 } 3138 // is_committed is unused. 3139 return linux_mprotect(addr, bytes, p); 3140 } 3141 3142 bool os::guard_memory(char* addr, size_t size) { 3143 return linux_mprotect(addr, size, PROT_NONE); 3144 } 3145 3146 bool os::unguard_memory(char* addr, size_t size) { 3147 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3148 } 3149 3150 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3151 size_t page_size) { 3152 bool result = false; 3153 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3154 MAP_ANONYMOUS|MAP_PRIVATE, 3155 -1, 0); 3156 if (p != MAP_FAILED) { 3157 void *aligned_p = align_ptr_up(p, page_size); 3158 3159 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3160 3161 munmap(p, page_size * 2); 3162 } 3163 3164 if (warn && !result) { 3165 warning("TransparentHugePages is not supported by the operating system."); 3166 } 3167 3168 return result; 3169 } 3170 3171 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3172 bool result = false; 3173 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3174 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3175 -1, 0); 3176 3177 if (p != MAP_FAILED) { 3178 // We don't know if this really is a huge page or not. 3179 FILE *fp = fopen("/proc/self/maps", "r"); 3180 if (fp) { 3181 while (!feof(fp)) { 3182 char chars[257]; 3183 long x = 0; 3184 if (fgets(chars, sizeof(chars), fp)) { 3185 if (sscanf(chars, "%lx-%*x", &x) == 1 3186 && x == (long)p) { 3187 if (strstr (chars, "hugepage")) { 3188 result = true; 3189 break; 3190 } 3191 } 3192 } 3193 } 3194 fclose(fp); 3195 } 3196 munmap(p, page_size); 3197 } 3198 3199 if (warn && !result) { 3200 warning("HugeTLBFS is not supported by the operating system."); 3201 } 3202 3203 return result; 3204 } 3205 3206 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3207 // 3208 // From the coredump_filter documentation: 3209 // 3210 // - (bit 0) anonymous private memory 3211 // - (bit 1) anonymous shared memory 3212 // - (bit 2) file-backed private memory 3213 // - (bit 3) file-backed shared memory 3214 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3215 // effective only if the bit 2 is cleared) 3216 // - (bit 5) hugetlb private memory 3217 // - (bit 6) hugetlb shared memory 3218 // 3219 static void set_coredump_filter(void) { 3220 FILE *f; 3221 long cdm; 3222 3223 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3224 return; 3225 } 3226 3227 if (fscanf(f, "%lx", &cdm) != 1) { 3228 fclose(f); 3229 return; 3230 } 3231 3232 rewind(f); 3233 3234 if ((cdm & LARGEPAGES_BIT) == 0) { 3235 cdm |= LARGEPAGES_BIT; 3236 fprintf(f, "%#lx", cdm); 3237 } 3238 3239 fclose(f); 3240 } 3241 3242 // Large page support 3243 3244 static size_t _large_page_size = 0; 3245 3246 size_t os::Linux::find_large_page_size() { 3247 size_t large_page_size = 0; 3248 3249 // large_page_size on Linux is used to round up heap size. x86 uses either 3250 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3251 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3252 // page as large as 256M. 3253 // 3254 // Here we try to figure out page size by parsing /proc/meminfo and looking 3255 // for a line with the following format: 3256 // Hugepagesize: 2048 kB 3257 // 3258 // If we can't determine the value (e.g. /proc is not mounted, or the text 3259 // format has been changed), we'll use the largest page size supported by 3260 // the processor. 3261 3262 #ifndef ZERO 3263 large_page_size = 3264 AARCH64_ONLY(2 * M) 3265 AMD64_ONLY(2 * M) 3266 ARM32_ONLY(2 * M) 3267 IA32_ONLY(4 * M) 3268 IA64_ONLY(256 * M) 3269 PPC_ONLY(4 * M) 3270 S390_ONLY(1 * M) 3271 SPARC_ONLY(4 * M); 3272 #endif // ZERO 3273 3274 FILE *fp = fopen("/proc/meminfo", "r"); 3275 if (fp) { 3276 while (!feof(fp)) { 3277 int x = 0; 3278 char buf[16]; 3279 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3280 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3281 large_page_size = x * K; 3282 break; 3283 } 3284 } else { 3285 // skip to next line 3286 for (;;) { 3287 int ch = fgetc(fp); 3288 if (ch == EOF || ch == (int)'\n') break; 3289 } 3290 } 3291 } 3292 fclose(fp); 3293 } 3294 3295 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3296 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3297 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3298 proper_unit_for_byte_size(large_page_size)); 3299 } 3300 3301 return large_page_size; 3302 } 3303 3304 size_t os::Linux::setup_large_page_size() { 3305 _large_page_size = Linux::find_large_page_size(); 3306 const size_t default_page_size = (size_t)Linux::page_size(); 3307 if (_large_page_size > default_page_size) { 3308 _page_sizes[0] = _large_page_size; 3309 _page_sizes[1] = default_page_size; 3310 _page_sizes[2] = 0; 3311 } 3312 3313 return _large_page_size; 3314 } 3315 3316 bool os::Linux::setup_large_page_type(size_t page_size) { 3317 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3318 FLAG_IS_DEFAULT(UseSHM) && 3319 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3320 3321 // The type of large pages has not been specified by the user. 3322 3323 // Try UseHugeTLBFS and then UseSHM. 3324 UseHugeTLBFS = UseSHM = true; 3325 3326 // Don't try UseTransparentHugePages since there are known 3327 // performance issues with it turned on. This might change in the future. 3328 UseTransparentHugePages = false; 3329 } 3330 3331 if (UseTransparentHugePages) { 3332 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3333 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3334 UseHugeTLBFS = false; 3335 UseSHM = false; 3336 return true; 3337 } 3338 UseTransparentHugePages = false; 3339 } 3340 3341 if (UseHugeTLBFS) { 3342 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3343 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3344 UseSHM = false; 3345 return true; 3346 } 3347 UseHugeTLBFS = false; 3348 } 3349 3350 return UseSHM; 3351 } 3352 3353 void os::large_page_init() { 3354 if (!UseLargePages && 3355 !UseTransparentHugePages && 3356 !UseHugeTLBFS && 3357 !UseSHM) { 3358 // Not using large pages. 3359 return; 3360 } 3361 3362 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3363 // The user explicitly turned off large pages. 3364 // Ignore the rest of the large pages flags. 3365 UseTransparentHugePages = false; 3366 UseHugeTLBFS = false; 3367 UseSHM = false; 3368 return; 3369 } 3370 3371 size_t large_page_size = Linux::setup_large_page_size(); 3372 UseLargePages = Linux::setup_large_page_type(large_page_size); 3373 3374 set_coredump_filter(); 3375 } 3376 3377 #ifndef SHM_HUGETLB 3378 #define SHM_HUGETLB 04000 3379 #endif 3380 3381 #define shm_warning_format(format, ...) \ 3382 do { \ 3383 if (UseLargePages && \ 3384 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3385 !FLAG_IS_DEFAULT(UseSHM) || \ 3386 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3387 warning(format, __VA_ARGS__); \ 3388 } \ 3389 } while (0) 3390 3391 #define shm_warning(str) shm_warning_format("%s", str) 3392 3393 #define shm_warning_with_errno(str) \ 3394 do { \ 3395 int err = errno; \ 3396 shm_warning_format(str " (error = %d)", err); \ 3397 } while (0) 3398 3399 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3400 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment"); 3401 3402 if (!is_size_aligned(alignment, SHMLBA)) { 3403 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3404 return NULL; 3405 } 3406 3407 // To ensure that we get 'alignment' aligned memory from shmat, 3408 // we pre-reserve aligned virtual memory and then attach to that. 3409 3410 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3411 if (pre_reserved_addr == NULL) { 3412 // Couldn't pre-reserve aligned memory. 3413 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3414 return NULL; 3415 } 3416 3417 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3418 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3419 3420 if ((intptr_t)addr == -1) { 3421 int err = errno; 3422 shm_warning_with_errno("Failed to attach shared memory."); 3423 3424 assert(err != EACCES, "Unexpected error"); 3425 assert(err != EIDRM, "Unexpected error"); 3426 assert(err != EINVAL, "Unexpected error"); 3427 3428 // Since we don't know if the kernel unmapped the pre-reserved memory area 3429 // we can't unmap it, since that would potentially unmap memory that was 3430 // mapped from other threads. 3431 return NULL; 3432 } 3433 3434 return addr; 3435 } 3436 3437 static char* shmat_at_address(int shmid, char* req_addr) { 3438 if (!is_ptr_aligned(req_addr, SHMLBA)) { 3439 assert(false, "Requested address needs to be SHMLBA aligned"); 3440 return NULL; 3441 } 3442 3443 char* addr = (char*)shmat(shmid, req_addr, 0); 3444 3445 if ((intptr_t)addr == -1) { 3446 shm_warning_with_errno("Failed to attach shared memory."); 3447 return NULL; 3448 } 3449 3450 return addr; 3451 } 3452 3453 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3454 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3455 if (req_addr != NULL) { 3456 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3457 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3458 return shmat_at_address(shmid, req_addr); 3459 } 3460 3461 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3462 // return large page size aligned memory addresses when req_addr == NULL. 3463 // However, if the alignment is larger than the large page size, we have 3464 // to manually ensure that the memory returned is 'alignment' aligned. 3465 if (alignment > os::large_page_size()) { 3466 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3467 return shmat_with_alignment(shmid, bytes, alignment); 3468 } else { 3469 return shmat_at_address(shmid, NULL); 3470 } 3471 } 3472 3473 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3474 char* req_addr, bool exec) { 3475 // "exec" is passed in but not used. Creating the shared image for 3476 // the code cache doesn't have an SHM_X executable permission to check. 3477 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3478 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3479 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address"); 3480 3481 if (!is_size_aligned(bytes, os::large_page_size())) { 3482 return NULL; // Fallback to small pages. 3483 } 3484 3485 // Create a large shared memory region to attach to based on size. 3486 // Currently, size is the total size of the heap. 3487 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3488 if (shmid == -1) { 3489 // Possible reasons for shmget failure: 3490 // 1. shmmax is too small for Java heap. 3491 // > check shmmax value: cat /proc/sys/kernel/shmmax 3492 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3493 // 2. not enough large page memory. 3494 // > check available large pages: cat /proc/meminfo 3495 // > increase amount of large pages: 3496 // echo new_value > /proc/sys/vm/nr_hugepages 3497 // Note 1: different Linux may use different name for this property, 3498 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3499 // Note 2: it's possible there's enough physical memory available but 3500 // they are so fragmented after a long run that they can't 3501 // coalesce into large pages. Try to reserve large pages when 3502 // the system is still "fresh". 3503 shm_warning_with_errno("Failed to reserve shared memory."); 3504 return NULL; 3505 } 3506 3507 // Attach to the region. 3508 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3509 3510 // Remove shmid. If shmat() is successful, the actual shared memory segment 3511 // will be deleted when it's detached by shmdt() or when the process 3512 // terminates. If shmat() is not successful this will remove the shared 3513 // segment immediately. 3514 shmctl(shmid, IPC_RMID, NULL); 3515 3516 return addr; 3517 } 3518 3519 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3520 int error) { 3521 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3522 3523 bool warn_on_failure = UseLargePages && 3524 (!FLAG_IS_DEFAULT(UseLargePages) || 3525 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3526 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3527 3528 if (warn_on_failure) { 3529 char msg[128]; 3530 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3531 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3532 warning("%s", msg); 3533 } 3534 } 3535 3536 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3537 char* req_addr, 3538 bool exec) { 3539 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3540 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3541 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3542 3543 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3544 char* addr = (char*)::mmap(req_addr, bytes, prot, 3545 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3546 -1, 0); 3547 3548 if (addr == MAP_FAILED) { 3549 warn_on_large_pages_failure(req_addr, bytes, errno); 3550 return NULL; 3551 } 3552 3553 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3554 3555 return addr; 3556 } 3557 3558 // Reserve memory using mmap(MAP_HUGETLB). 3559 // - bytes shall be a multiple of alignment. 3560 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3561 // - alignment sets the alignment at which memory shall be allocated. 3562 // It must be a multiple of allocation granularity. 3563 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3564 // req_addr or NULL. 3565 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3566 size_t alignment, 3567 char* req_addr, 3568 bool exec) { 3569 size_t large_page_size = os::large_page_size(); 3570 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3571 3572 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3573 assert(is_size_aligned(bytes, alignment), "Must be"); 3574 3575 // First reserve - but not commit - the address range in small pages. 3576 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3577 3578 if (start == NULL) { 3579 return NULL; 3580 } 3581 3582 assert(is_ptr_aligned(start, alignment), "Must be"); 3583 3584 char* end = start + bytes; 3585 3586 // Find the regions of the allocated chunk that can be promoted to large pages. 3587 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3588 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3589 3590 size_t lp_bytes = lp_end - lp_start; 3591 3592 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3593 3594 if (lp_bytes == 0) { 3595 // The mapped region doesn't even span the start and the end of a large page. 3596 // Fall back to allocate a non-special area. 3597 ::munmap(start, end - start); 3598 return NULL; 3599 } 3600 3601 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3602 3603 void* result; 3604 3605 // Commit small-paged leading area. 3606 if (start != lp_start) { 3607 result = ::mmap(start, lp_start - start, prot, 3608 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3609 -1, 0); 3610 if (result == MAP_FAILED) { 3611 ::munmap(lp_start, end - lp_start); 3612 return NULL; 3613 } 3614 } 3615 3616 // Commit large-paged area. 3617 result = ::mmap(lp_start, lp_bytes, prot, 3618 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3619 -1, 0); 3620 if (result == MAP_FAILED) { 3621 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3622 // If the mmap above fails, the large pages region will be unmapped and we 3623 // have regions before and after with small pages. Release these regions. 3624 // 3625 // | mapped | unmapped | mapped | 3626 // ^ ^ ^ ^ 3627 // start lp_start lp_end end 3628 // 3629 ::munmap(start, lp_start - start); 3630 ::munmap(lp_end, end - lp_end); 3631 return NULL; 3632 } 3633 3634 // Commit small-paged trailing area. 3635 if (lp_end != end) { 3636 result = ::mmap(lp_end, end - lp_end, prot, 3637 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3638 -1, 0); 3639 if (result == MAP_FAILED) { 3640 ::munmap(start, lp_end - start); 3641 return NULL; 3642 } 3643 } 3644 3645 return start; 3646 } 3647 3648 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3649 size_t alignment, 3650 char* req_addr, 3651 bool exec) { 3652 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3653 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3654 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3655 assert(is_power_of_2(os::large_page_size()), "Must be"); 3656 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3657 3658 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3659 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3660 } else { 3661 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3662 } 3663 } 3664 3665 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3666 char* req_addr, bool exec) { 3667 assert(UseLargePages, "only for large pages"); 3668 3669 char* addr; 3670 if (UseSHM) { 3671 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3672 } else { 3673 assert(UseHugeTLBFS, "must be"); 3674 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3675 } 3676 3677 if (addr != NULL) { 3678 if (UseNUMAInterleaving) { 3679 numa_make_global(addr, bytes); 3680 } 3681 3682 // The memory is committed 3683 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3684 } 3685 3686 return addr; 3687 } 3688 3689 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3690 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3691 return shmdt(base) == 0; 3692 } 3693 3694 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3695 return pd_release_memory(base, bytes); 3696 } 3697 3698 bool os::release_memory_special(char* base, size_t bytes) { 3699 bool res; 3700 if (MemTracker::tracking_level() > NMT_minimal) { 3701 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3702 res = os::Linux::release_memory_special_impl(base, bytes); 3703 if (res) { 3704 tkr.record((address)base, bytes); 3705 } 3706 3707 } else { 3708 res = os::Linux::release_memory_special_impl(base, bytes); 3709 } 3710 return res; 3711 } 3712 3713 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3714 assert(UseLargePages, "only for large pages"); 3715 bool res; 3716 3717 if (UseSHM) { 3718 res = os::Linux::release_memory_special_shm(base, bytes); 3719 } else { 3720 assert(UseHugeTLBFS, "must be"); 3721 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3722 } 3723 return res; 3724 } 3725 3726 size_t os::large_page_size() { 3727 return _large_page_size; 3728 } 3729 3730 // With SysV SHM the entire memory region must be allocated as shared 3731 // memory. 3732 // HugeTLBFS allows application to commit large page memory on demand. 3733 // However, when committing memory with HugeTLBFS fails, the region 3734 // that was supposed to be committed will lose the old reservation 3735 // and allow other threads to steal that memory region. Because of this 3736 // behavior we can't commit HugeTLBFS memory. 3737 bool os::can_commit_large_page_memory() { 3738 return UseTransparentHugePages; 3739 } 3740 3741 bool os::can_execute_large_page_memory() { 3742 return UseTransparentHugePages || UseHugeTLBFS; 3743 } 3744 3745 // Reserve memory at an arbitrary address, only if that area is 3746 // available (and not reserved for something else). 3747 3748 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3749 const int max_tries = 10; 3750 char* base[max_tries]; 3751 size_t size[max_tries]; 3752 const size_t gap = 0x000000; 3753 3754 // Assert only that the size is a multiple of the page size, since 3755 // that's all that mmap requires, and since that's all we really know 3756 // about at this low abstraction level. If we need higher alignment, 3757 // we can either pass an alignment to this method or verify alignment 3758 // in one of the methods further up the call chain. See bug 5044738. 3759 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3760 3761 // Repeatedly allocate blocks until the block is allocated at the 3762 // right spot. 3763 3764 // Linux mmap allows caller to pass an address as hint; give it a try first, 3765 // if kernel honors the hint then we can return immediately. 3766 char * addr = anon_mmap(requested_addr, bytes, false); 3767 if (addr == requested_addr) { 3768 return requested_addr; 3769 } 3770 3771 if (addr != NULL) { 3772 // mmap() is successful but it fails to reserve at the requested address 3773 anon_munmap(addr, bytes); 3774 } 3775 3776 int i; 3777 for (i = 0; i < max_tries; ++i) { 3778 base[i] = reserve_memory(bytes); 3779 3780 if (base[i] != NULL) { 3781 // Is this the block we wanted? 3782 if (base[i] == requested_addr) { 3783 size[i] = bytes; 3784 break; 3785 } 3786 3787 // Does this overlap the block we wanted? Give back the overlapped 3788 // parts and try again. 3789 3790 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3791 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3792 unmap_memory(base[i], top_overlap); 3793 base[i] += top_overlap; 3794 size[i] = bytes - top_overlap; 3795 } else { 3796 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3797 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3798 unmap_memory(requested_addr, bottom_overlap); 3799 size[i] = bytes - bottom_overlap; 3800 } else { 3801 size[i] = bytes; 3802 } 3803 } 3804 } 3805 } 3806 3807 // Give back the unused reserved pieces. 3808 3809 for (int j = 0; j < i; ++j) { 3810 if (base[j] != NULL) { 3811 unmap_memory(base[j], size[j]); 3812 } 3813 } 3814 3815 if (i < max_tries) { 3816 return requested_addr; 3817 } else { 3818 return NULL; 3819 } 3820 } 3821 3822 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3823 return ::read(fd, buf, nBytes); 3824 } 3825 3826 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3827 return ::pread(fd, buf, nBytes, offset); 3828 } 3829 3830 // Short sleep, direct OS call. 3831 // 3832 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3833 // sched_yield(2) will actually give up the CPU: 3834 // 3835 // * Alone on this pariticular CPU, keeps running. 3836 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3837 // (pre 2.6.39). 3838 // 3839 // So calling this with 0 is an alternative. 3840 // 3841 void os::naked_short_sleep(jlong ms) { 3842 struct timespec req; 3843 3844 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3845 req.tv_sec = 0; 3846 if (ms > 0) { 3847 req.tv_nsec = (ms % 1000) * 1000000; 3848 } else { 3849 req.tv_nsec = 1; 3850 } 3851 3852 nanosleep(&req, NULL); 3853 3854 return; 3855 } 3856 3857 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3858 void os::infinite_sleep() { 3859 while (true) { // sleep forever ... 3860 ::sleep(100); // ... 100 seconds at a time 3861 } 3862 } 3863 3864 // Used to convert frequent JVM_Yield() to nops 3865 bool os::dont_yield() { 3866 return DontYieldALot; 3867 } 3868 3869 void os::naked_yield() { 3870 sched_yield(); 3871 } 3872 3873 //////////////////////////////////////////////////////////////////////////////// 3874 // thread priority support 3875 3876 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3877 // only supports dynamic priority, static priority must be zero. For real-time 3878 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3879 // However, for large multi-threaded applications, SCHED_RR is not only slower 3880 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3881 // of 5 runs - Sep 2005). 3882 // 3883 // The following code actually changes the niceness of kernel-thread/LWP. It 3884 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3885 // not the entire user process, and user level threads are 1:1 mapped to kernel 3886 // threads. It has always been the case, but could change in the future. For 3887 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3888 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3889 3890 int os::java_to_os_priority[CriticalPriority + 1] = { 3891 19, // 0 Entry should never be used 3892 3893 4, // 1 MinPriority 3894 3, // 2 3895 2, // 3 3896 3897 1, // 4 3898 0, // 5 NormPriority 3899 -1, // 6 3900 3901 -2, // 7 3902 -3, // 8 3903 -4, // 9 NearMaxPriority 3904 3905 -5, // 10 MaxPriority 3906 3907 -5 // 11 CriticalPriority 3908 }; 3909 3910 static int prio_init() { 3911 if (ThreadPriorityPolicy == 1) { 3912 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3913 // if effective uid is not root. Perhaps, a more elegant way of doing 3914 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3915 if (geteuid() != 0) { 3916 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3917 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3918 } 3919 ThreadPriorityPolicy = 0; 3920 } 3921 } 3922 if (UseCriticalJavaThreadPriority) { 3923 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3924 } 3925 return 0; 3926 } 3927 3928 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3929 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3930 3931 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3932 return (ret == 0) ? OS_OK : OS_ERR; 3933 } 3934 3935 OSReturn os::get_native_priority(const Thread* const thread, 3936 int *priority_ptr) { 3937 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3938 *priority_ptr = java_to_os_priority[NormPriority]; 3939 return OS_OK; 3940 } 3941 3942 errno = 0; 3943 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3944 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3945 } 3946 3947 // Hint to the underlying OS that a task switch would not be good. 3948 // Void return because it's a hint and can fail. 3949 void os::hint_no_preempt() {} 3950 3951 //////////////////////////////////////////////////////////////////////////////// 3952 // suspend/resume support 3953 3954 // the low-level signal-based suspend/resume support is a remnant from the 3955 // old VM-suspension that used to be for java-suspension, safepoints etc, 3956 // within hotspot. Now there is a single use-case for this: 3957 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3958 // that runs in the watcher thread. 3959 // The remaining code is greatly simplified from the more general suspension 3960 // code that used to be used. 3961 // 3962 // The protocol is quite simple: 3963 // - suspend: 3964 // - sends a signal to the target thread 3965 // - polls the suspend state of the osthread using a yield loop 3966 // - target thread signal handler (SR_handler) sets suspend state 3967 // and blocks in sigsuspend until continued 3968 // - resume: 3969 // - sets target osthread state to continue 3970 // - sends signal to end the sigsuspend loop in the SR_handler 3971 // 3972 // Note that the SR_lock plays no role in this suspend/resume protocol, 3973 // but is checked for NULL in SR_handler as a thread termination indicator. 3974 3975 static void resume_clear_context(OSThread *osthread) { 3976 osthread->set_ucontext(NULL); 3977 osthread->set_siginfo(NULL); 3978 } 3979 3980 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3981 ucontext_t* context) { 3982 osthread->set_ucontext(context); 3983 osthread->set_siginfo(siginfo); 3984 } 3985 3986 // Handler function invoked when a thread's execution is suspended or 3987 // resumed. We have to be careful that only async-safe functions are 3988 // called here (Note: most pthread functions are not async safe and 3989 // should be avoided.) 3990 // 3991 // Note: sigwait() is a more natural fit than sigsuspend() from an 3992 // interface point of view, but sigwait() prevents the signal hander 3993 // from being run. libpthread would get very confused by not having 3994 // its signal handlers run and prevents sigwait()'s use with the 3995 // mutex granting granting signal. 3996 // 3997 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3998 // 3999 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4000 // Save and restore errno to avoid confusing native code with EINTR 4001 // after sigsuspend. 4002 int old_errno = errno; 4003 4004 Thread* thread = Thread::current_or_null_safe(); 4005 assert(thread != NULL, "Missing current thread in SR_handler"); 4006 4007 // On some systems we have seen signal delivery get "stuck" until the signal 4008 // mask is changed as part of thread termination. Check that the current thread 4009 // has not already terminated (via SR_lock()) - else the following assertion 4010 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4011 // destructor has completed. 4012 4013 if (thread->SR_lock() == NULL) { 4014 return; 4015 } 4016 4017 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4018 4019 OSThread* osthread = thread->osthread(); 4020 4021 os::SuspendResume::State current = osthread->sr.state(); 4022 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4023 suspend_save_context(osthread, siginfo, context); 4024 4025 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4026 os::SuspendResume::State state = osthread->sr.suspended(); 4027 if (state == os::SuspendResume::SR_SUSPENDED) { 4028 sigset_t suspend_set; // signals for sigsuspend() 4029 sigemptyset(&suspend_set); 4030 // get current set of blocked signals and unblock resume signal 4031 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4032 sigdelset(&suspend_set, SR_signum); 4033 4034 sr_semaphore.signal(); 4035 // wait here until we are resumed 4036 while (1) { 4037 sigsuspend(&suspend_set); 4038 4039 os::SuspendResume::State result = osthread->sr.running(); 4040 if (result == os::SuspendResume::SR_RUNNING) { 4041 sr_semaphore.signal(); 4042 break; 4043 } 4044 } 4045 4046 } else if (state == os::SuspendResume::SR_RUNNING) { 4047 // request was cancelled, continue 4048 } else { 4049 ShouldNotReachHere(); 4050 } 4051 4052 resume_clear_context(osthread); 4053 } else if (current == os::SuspendResume::SR_RUNNING) { 4054 // request was cancelled, continue 4055 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4056 // ignore 4057 } else { 4058 // ignore 4059 } 4060 4061 errno = old_errno; 4062 } 4063 4064 static int SR_initialize() { 4065 struct sigaction act; 4066 char *s; 4067 4068 // Get signal number to use for suspend/resume 4069 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4070 int sig = ::strtol(s, 0, 10); 4071 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4072 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4073 SR_signum = sig; 4074 } else { 4075 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4076 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4077 } 4078 } 4079 4080 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4081 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4082 4083 sigemptyset(&SR_sigset); 4084 sigaddset(&SR_sigset, SR_signum); 4085 4086 // Set up signal handler for suspend/resume 4087 act.sa_flags = SA_RESTART|SA_SIGINFO; 4088 act.sa_handler = (void (*)(int)) SR_handler; 4089 4090 // SR_signum is blocked by default. 4091 // 4528190 - We also need to block pthread restart signal (32 on all 4092 // supported Linux platforms). Note that LinuxThreads need to block 4093 // this signal for all threads to work properly. So we don't have 4094 // to use hard-coded signal number when setting up the mask. 4095 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4096 4097 if (sigaction(SR_signum, &act, 0) == -1) { 4098 return -1; 4099 } 4100 4101 // Save signal flag 4102 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4103 return 0; 4104 } 4105 4106 static int sr_notify(OSThread* osthread) { 4107 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4108 assert_status(status == 0, status, "pthread_kill"); 4109 return status; 4110 } 4111 4112 // "Randomly" selected value for how long we want to spin 4113 // before bailing out on suspending a thread, also how often 4114 // we send a signal to a thread we want to resume 4115 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4116 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4117 4118 // returns true on success and false on error - really an error is fatal 4119 // but this seems the normal response to library errors 4120 static bool do_suspend(OSThread* osthread) { 4121 assert(osthread->sr.is_running(), "thread should be running"); 4122 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4123 4124 // mark as suspended and send signal 4125 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4126 // failed to switch, state wasn't running? 4127 ShouldNotReachHere(); 4128 return false; 4129 } 4130 4131 if (sr_notify(osthread) != 0) { 4132 ShouldNotReachHere(); 4133 } 4134 4135 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4136 while (true) { 4137 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4138 break; 4139 } else { 4140 // timeout 4141 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4142 if (cancelled == os::SuspendResume::SR_RUNNING) { 4143 return false; 4144 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4145 // make sure that we consume the signal on the semaphore as well 4146 sr_semaphore.wait(); 4147 break; 4148 } else { 4149 ShouldNotReachHere(); 4150 return false; 4151 } 4152 } 4153 } 4154 4155 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4156 return true; 4157 } 4158 4159 static void do_resume(OSThread* osthread) { 4160 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4161 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4162 4163 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4164 // failed to switch to WAKEUP_REQUEST 4165 ShouldNotReachHere(); 4166 return; 4167 } 4168 4169 while (true) { 4170 if (sr_notify(osthread) == 0) { 4171 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4172 if (osthread->sr.is_running()) { 4173 return; 4174 } 4175 } 4176 } else { 4177 ShouldNotReachHere(); 4178 } 4179 } 4180 4181 guarantee(osthread->sr.is_running(), "Must be running!"); 4182 } 4183 4184 /////////////////////////////////////////////////////////////////////////////////// 4185 // signal handling (except suspend/resume) 4186 4187 // This routine may be used by user applications as a "hook" to catch signals. 4188 // The user-defined signal handler must pass unrecognized signals to this 4189 // routine, and if it returns true (non-zero), then the signal handler must 4190 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4191 // routine will never retun false (zero), but instead will execute a VM panic 4192 // routine kill the process. 4193 // 4194 // If this routine returns false, it is OK to call it again. This allows 4195 // the user-defined signal handler to perform checks either before or after 4196 // the VM performs its own checks. Naturally, the user code would be making 4197 // a serious error if it tried to handle an exception (such as a null check 4198 // or breakpoint) that the VM was generating for its own correct operation. 4199 // 4200 // This routine may recognize any of the following kinds of signals: 4201 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4202 // It should be consulted by handlers for any of those signals. 4203 // 4204 // The caller of this routine must pass in the three arguments supplied 4205 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4206 // field of the structure passed to sigaction(). This routine assumes that 4207 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4208 // 4209 // Note that the VM will print warnings if it detects conflicting signal 4210 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4211 // 4212 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4213 siginfo_t* siginfo, 4214 void* ucontext, 4215 int abort_if_unrecognized); 4216 4217 void signalHandler(int sig, siginfo_t* info, void* uc) { 4218 assert(info != NULL && uc != NULL, "it must be old kernel"); 4219 int orig_errno = errno; // Preserve errno value over signal handler. 4220 JVM_handle_linux_signal(sig, info, uc, true); 4221 errno = orig_errno; 4222 } 4223 4224 4225 // This boolean allows users to forward their own non-matching signals 4226 // to JVM_handle_linux_signal, harmlessly. 4227 bool os::Linux::signal_handlers_are_installed = false; 4228 4229 // For signal-chaining 4230 struct sigaction sigact[NSIG]; 4231 uint64_t sigs = 0; 4232 #if (64 < NSIG-1) 4233 #error "Not all signals can be encoded in sigs. Adapt its type!" 4234 #endif 4235 bool os::Linux::libjsig_is_loaded = false; 4236 typedef struct sigaction *(*get_signal_t)(int); 4237 get_signal_t os::Linux::get_signal_action = NULL; 4238 4239 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4240 struct sigaction *actp = NULL; 4241 4242 if (libjsig_is_loaded) { 4243 // Retrieve the old signal handler from libjsig 4244 actp = (*get_signal_action)(sig); 4245 } 4246 if (actp == NULL) { 4247 // Retrieve the preinstalled signal handler from jvm 4248 actp = get_preinstalled_handler(sig); 4249 } 4250 4251 return actp; 4252 } 4253 4254 static bool call_chained_handler(struct sigaction *actp, int sig, 4255 siginfo_t *siginfo, void *context) { 4256 // Call the old signal handler 4257 if (actp->sa_handler == SIG_DFL) { 4258 // It's more reasonable to let jvm treat it as an unexpected exception 4259 // instead of taking the default action. 4260 return false; 4261 } else if (actp->sa_handler != SIG_IGN) { 4262 if ((actp->sa_flags & SA_NODEFER) == 0) { 4263 // automaticlly block the signal 4264 sigaddset(&(actp->sa_mask), sig); 4265 } 4266 4267 sa_handler_t hand = NULL; 4268 sa_sigaction_t sa = NULL; 4269 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4270 // retrieve the chained handler 4271 if (siginfo_flag_set) { 4272 sa = actp->sa_sigaction; 4273 } else { 4274 hand = actp->sa_handler; 4275 } 4276 4277 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4278 actp->sa_handler = SIG_DFL; 4279 } 4280 4281 // try to honor the signal mask 4282 sigset_t oset; 4283 sigemptyset(&oset); 4284 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4285 4286 // call into the chained handler 4287 if (siginfo_flag_set) { 4288 (*sa)(sig, siginfo, context); 4289 } else { 4290 (*hand)(sig); 4291 } 4292 4293 // restore the signal mask 4294 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4295 } 4296 // Tell jvm's signal handler the signal is taken care of. 4297 return true; 4298 } 4299 4300 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4301 bool chained = false; 4302 // signal-chaining 4303 if (UseSignalChaining) { 4304 struct sigaction *actp = get_chained_signal_action(sig); 4305 if (actp != NULL) { 4306 chained = call_chained_handler(actp, sig, siginfo, context); 4307 } 4308 } 4309 return chained; 4310 } 4311 4312 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4313 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4314 return &sigact[sig]; 4315 } 4316 return NULL; 4317 } 4318 4319 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4320 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4321 sigact[sig] = oldAct; 4322 sigs |= (uint64_t)1 << (sig-1); 4323 } 4324 4325 // for diagnostic 4326 int sigflags[NSIG]; 4327 4328 int os::Linux::get_our_sigflags(int sig) { 4329 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4330 return sigflags[sig]; 4331 } 4332 4333 void os::Linux::set_our_sigflags(int sig, int flags) { 4334 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4335 if (sig > 0 && sig < NSIG) { 4336 sigflags[sig] = flags; 4337 } 4338 } 4339 4340 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4341 // Check for overwrite. 4342 struct sigaction oldAct; 4343 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4344 4345 void* oldhand = oldAct.sa_sigaction 4346 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4347 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4348 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4349 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4350 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4351 if (AllowUserSignalHandlers || !set_installed) { 4352 // Do not overwrite; user takes responsibility to forward to us. 4353 return; 4354 } else if (UseSignalChaining) { 4355 // save the old handler in jvm 4356 save_preinstalled_handler(sig, oldAct); 4357 // libjsig also interposes the sigaction() call below and saves the 4358 // old sigaction on it own. 4359 } else { 4360 fatal("Encountered unexpected pre-existing sigaction handler " 4361 "%#lx for signal %d.", (long)oldhand, sig); 4362 } 4363 } 4364 4365 struct sigaction sigAct; 4366 sigfillset(&(sigAct.sa_mask)); 4367 sigAct.sa_handler = SIG_DFL; 4368 if (!set_installed) { 4369 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4370 } else { 4371 sigAct.sa_sigaction = signalHandler; 4372 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4373 } 4374 // Save flags, which are set by ours 4375 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4376 sigflags[sig] = sigAct.sa_flags; 4377 4378 int ret = sigaction(sig, &sigAct, &oldAct); 4379 assert(ret == 0, "check"); 4380 4381 void* oldhand2 = oldAct.sa_sigaction 4382 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4383 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4384 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4385 } 4386 4387 // install signal handlers for signals that HotSpot needs to 4388 // handle in order to support Java-level exception handling. 4389 4390 void os::Linux::install_signal_handlers() { 4391 if (!signal_handlers_are_installed) { 4392 signal_handlers_are_installed = true; 4393 4394 // signal-chaining 4395 typedef void (*signal_setting_t)(); 4396 signal_setting_t begin_signal_setting = NULL; 4397 signal_setting_t end_signal_setting = NULL; 4398 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4399 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4400 if (begin_signal_setting != NULL) { 4401 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4402 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4403 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4404 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4405 libjsig_is_loaded = true; 4406 assert(UseSignalChaining, "should enable signal-chaining"); 4407 } 4408 if (libjsig_is_loaded) { 4409 // Tell libjsig jvm is setting signal handlers 4410 (*begin_signal_setting)(); 4411 } 4412 4413 set_signal_handler(SIGSEGV, true); 4414 set_signal_handler(SIGPIPE, true); 4415 set_signal_handler(SIGBUS, true); 4416 set_signal_handler(SIGILL, true); 4417 set_signal_handler(SIGFPE, true); 4418 #if defined(PPC64) 4419 set_signal_handler(SIGTRAP, true); 4420 #endif 4421 set_signal_handler(SIGXFSZ, true); 4422 4423 if (libjsig_is_loaded) { 4424 // Tell libjsig jvm finishes setting signal handlers 4425 (*end_signal_setting)(); 4426 } 4427 4428 // We don't activate signal checker if libjsig is in place, we trust ourselves 4429 // and if UserSignalHandler is installed all bets are off. 4430 // Log that signal checking is off only if -verbose:jni is specified. 4431 if (CheckJNICalls) { 4432 if (libjsig_is_loaded) { 4433 if (PrintJNIResolving) { 4434 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4435 } 4436 check_signals = false; 4437 } 4438 if (AllowUserSignalHandlers) { 4439 if (PrintJNIResolving) { 4440 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4441 } 4442 check_signals = false; 4443 } 4444 } 4445 } 4446 } 4447 4448 // This is the fastest way to get thread cpu time on Linux. 4449 // Returns cpu time (user+sys) for any thread, not only for current. 4450 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4451 // It might work on 2.6.10+ with a special kernel/glibc patch. 4452 // For reference, please, see IEEE Std 1003.1-2004: 4453 // http://www.unix.org/single_unix_specification 4454 4455 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4456 struct timespec tp; 4457 int rc = os::Linux::clock_gettime(clockid, &tp); 4458 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4459 4460 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4461 } 4462 4463 void os::Linux::initialize_os_info() { 4464 assert(_os_version == 0, "OS info already initialized"); 4465 4466 struct utsname _uname; 4467 4468 uint32_t major; 4469 uint32_t minor; 4470 uint32_t fix; 4471 4472 int rc; 4473 4474 // Kernel version is unknown if 4475 // verification below fails. 4476 _os_version = 0x01000000; 4477 4478 rc = uname(&_uname); 4479 if (rc != -1) { 4480 4481 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4482 if (rc == 3) { 4483 4484 if (major < 256 && minor < 256 && fix < 256) { 4485 // Kernel version format is as expected, 4486 // set it overriding unknown state. 4487 _os_version = (major << 16) | 4488 (minor << 8 ) | 4489 (fix << 0 ) ; 4490 } 4491 } 4492 } 4493 } 4494 4495 uint32_t os::Linux::os_version() { 4496 assert(_os_version != 0, "not initialized"); 4497 return _os_version & 0x00FFFFFF; 4498 } 4499 4500 bool os::Linux::os_version_is_known() { 4501 assert(_os_version != 0, "not initialized"); 4502 return _os_version & 0x01000000 ? false : true; 4503 } 4504 4505 ///// 4506 // glibc on Linux platform uses non-documented flag 4507 // to indicate, that some special sort of signal 4508 // trampoline is used. 4509 // We will never set this flag, and we should 4510 // ignore this flag in our diagnostic 4511 #ifdef SIGNIFICANT_SIGNAL_MASK 4512 #undef SIGNIFICANT_SIGNAL_MASK 4513 #endif 4514 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4515 4516 static const char* get_signal_handler_name(address handler, 4517 char* buf, int buflen) { 4518 int offset = 0; 4519 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4520 if (found) { 4521 // skip directory names 4522 const char *p1, *p2; 4523 p1 = buf; 4524 size_t len = strlen(os::file_separator()); 4525 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4526 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4527 } else { 4528 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4529 } 4530 return buf; 4531 } 4532 4533 static void print_signal_handler(outputStream* st, int sig, 4534 char* buf, size_t buflen) { 4535 struct sigaction sa; 4536 4537 sigaction(sig, NULL, &sa); 4538 4539 // See comment for SIGNIFICANT_SIGNAL_MASK define 4540 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4541 4542 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4543 4544 address handler = (sa.sa_flags & SA_SIGINFO) 4545 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4546 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4547 4548 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4549 st->print("SIG_DFL"); 4550 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4551 st->print("SIG_IGN"); 4552 } else { 4553 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4554 } 4555 4556 st->print(", sa_mask[0]="); 4557 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4558 4559 address rh = VMError::get_resetted_sighandler(sig); 4560 // May be, handler was resetted by VMError? 4561 if (rh != NULL) { 4562 handler = rh; 4563 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4564 } 4565 4566 st->print(", sa_flags="); 4567 os::Posix::print_sa_flags(st, sa.sa_flags); 4568 4569 // Check: is it our handler? 4570 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4571 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4572 // It is our signal handler 4573 // check for flags, reset system-used one! 4574 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4575 st->print( 4576 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4577 os::Linux::get_our_sigflags(sig)); 4578 } 4579 } 4580 st->cr(); 4581 } 4582 4583 4584 #define DO_SIGNAL_CHECK(sig) \ 4585 do { \ 4586 if (!sigismember(&check_signal_done, sig)) { \ 4587 os::Linux::check_signal_handler(sig); \ 4588 } \ 4589 } while (0) 4590 4591 // This method is a periodic task to check for misbehaving JNI applications 4592 // under CheckJNI, we can add any periodic checks here 4593 4594 void os::run_periodic_checks() { 4595 if (check_signals == false) return; 4596 4597 // SEGV and BUS if overridden could potentially prevent 4598 // generation of hs*.log in the event of a crash, debugging 4599 // such a case can be very challenging, so we absolutely 4600 // check the following for a good measure: 4601 DO_SIGNAL_CHECK(SIGSEGV); 4602 DO_SIGNAL_CHECK(SIGILL); 4603 DO_SIGNAL_CHECK(SIGFPE); 4604 DO_SIGNAL_CHECK(SIGBUS); 4605 DO_SIGNAL_CHECK(SIGPIPE); 4606 DO_SIGNAL_CHECK(SIGXFSZ); 4607 #if defined(PPC64) 4608 DO_SIGNAL_CHECK(SIGTRAP); 4609 #endif 4610 4611 // ReduceSignalUsage allows the user to override these handlers 4612 // see comments at the very top and jvm_solaris.h 4613 if (!ReduceSignalUsage) { 4614 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4615 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4616 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4617 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4618 } 4619 4620 DO_SIGNAL_CHECK(SR_signum); 4621 } 4622 4623 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4624 4625 static os_sigaction_t os_sigaction = NULL; 4626 4627 void os::Linux::check_signal_handler(int sig) { 4628 char buf[O_BUFLEN]; 4629 address jvmHandler = NULL; 4630 4631 4632 struct sigaction act; 4633 if (os_sigaction == NULL) { 4634 // only trust the default sigaction, in case it has been interposed 4635 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4636 if (os_sigaction == NULL) return; 4637 } 4638 4639 os_sigaction(sig, (struct sigaction*)NULL, &act); 4640 4641 4642 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4643 4644 address thisHandler = (act.sa_flags & SA_SIGINFO) 4645 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4646 : CAST_FROM_FN_PTR(address, act.sa_handler); 4647 4648 4649 switch (sig) { 4650 case SIGSEGV: 4651 case SIGBUS: 4652 case SIGFPE: 4653 case SIGPIPE: 4654 case SIGILL: 4655 case SIGXFSZ: 4656 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4657 break; 4658 4659 case SHUTDOWN1_SIGNAL: 4660 case SHUTDOWN2_SIGNAL: 4661 case SHUTDOWN3_SIGNAL: 4662 case BREAK_SIGNAL: 4663 jvmHandler = (address)user_handler(); 4664 break; 4665 4666 default: 4667 if (sig == SR_signum) { 4668 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4669 } else { 4670 return; 4671 } 4672 break; 4673 } 4674 4675 if (thisHandler != jvmHandler) { 4676 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4677 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4678 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4679 // No need to check this sig any longer 4680 sigaddset(&check_signal_done, sig); 4681 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4682 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4683 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4684 exception_name(sig, buf, O_BUFLEN)); 4685 } 4686 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4687 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4688 tty->print("expected:"); 4689 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4690 tty->cr(); 4691 tty->print(" found:"); 4692 os::Posix::print_sa_flags(tty, act.sa_flags); 4693 tty->cr(); 4694 // No need to check this sig any longer 4695 sigaddset(&check_signal_done, sig); 4696 } 4697 4698 // Dump all the signal 4699 if (sigismember(&check_signal_done, sig)) { 4700 print_signal_handlers(tty, buf, O_BUFLEN); 4701 } 4702 } 4703 4704 extern void report_error(char* file_name, int line_no, char* title, 4705 char* format, ...); 4706 4707 // this is called _before_ the most of global arguments have been parsed 4708 void os::init(void) { 4709 char dummy; // used to get a guess on initial stack address 4710 // first_hrtime = gethrtime(); 4711 4712 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4713 4714 init_random(1234567); 4715 4716 ThreadCritical::initialize(); 4717 4718 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4719 if (Linux::page_size() == -1) { 4720 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4721 os::strerror(errno)); 4722 } 4723 init_page_sizes((size_t) Linux::page_size()); 4724 4725 Linux::initialize_system_info(); 4726 4727 Linux::initialize_os_info(); 4728 4729 // main_thread points to the aboriginal thread 4730 Linux::_main_thread = pthread_self(); 4731 4732 Linux::clock_init(); 4733 initial_time_count = javaTimeNanos(); 4734 4735 // pthread_condattr initialization for monotonic clock 4736 int status; 4737 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4738 if ((status = pthread_condattr_init(_condattr)) != 0) { 4739 fatal("pthread_condattr_init: %s", os::strerror(status)); 4740 } 4741 // Only set the clock if CLOCK_MONOTONIC is available 4742 if (os::supports_monotonic_clock()) { 4743 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4744 if (status == EINVAL) { 4745 warning("Unable to use monotonic clock with relative timed-waits" \ 4746 " - changes to the time-of-day clock may have adverse affects"); 4747 } else { 4748 fatal("pthread_condattr_setclock: %s", os::strerror(status)); 4749 } 4750 } 4751 } 4752 // else it defaults to CLOCK_REALTIME 4753 4754 // retrieve entry point for pthread_setname_np 4755 Linux::_pthread_setname_np = 4756 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4757 4758 } 4759 4760 // To install functions for atexit system call 4761 extern "C" { 4762 static void perfMemory_exit_helper() { 4763 perfMemory_exit(); 4764 } 4765 } 4766 4767 // this is called _after_ the global arguments have been parsed 4768 jint os::init_2(void) { 4769 Linux::fast_thread_clock_init(); 4770 4771 // Allocate a single page and mark it as readable for safepoint polling 4772 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4773 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4774 4775 os::set_polling_page(polling_page); 4776 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page)); 4777 4778 if (!UseMembar) { 4779 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4780 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4781 os::set_memory_serialize_page(mem_serialize_page); 4782 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page)); 4783 } 4784 4785 // initialize suspend/resume support - must do this before signal_sets_init() 4786 if (SR_initialize() != 0) { 4787 perror("SR_initialize failed"); 4788 return JNI_ERR; 4789 } 4790 4791 Linux::signal_sets_init(); 4792 Linux::install_signal_handlers(); 4793 4794 // Check and sets minimum stack sizes against command line options 4795 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 4796 return JNI_ERR; 4797 } 4798 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4799 4800 #if defined(IA32) 4801 workaround_expand_exec_shield_cs_limit(); 4802 #endif 4803 4804 Linux::libpthread_init(); 4805 log_info(os)("HotSpot is running with %s, %s", 4806 Linux::glibc_version(), Linux::libpthread_version()); 4807 4808 if (UseNUMA) { 4809 if (!Linux::libnuma_init()) { 4810 UseNUMA = false; 4811 } else { 4812 if ((Linux::numa_max_node() < 1)) { 4813 // There's only one node(they start from 0), disable NUMA. 4814 UseNUMA = false; 4815 } 4816 } 4817 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4818 // we can make the adaptive lgrp chunk resizing work. If the user specified 4819 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4820 // disable adaptive resizing. 4821 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4822 if (FLAG_IS_DEFAULT(UseNUMA)) { 4823 UseNUMA = false; 4824 } else { 4825 if (FLAG_IS_DEFAULT(UseLargePages) && 4826 FLAG_IS_DEFAULT(UseSHM) && 4827 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4828 UseLargePages = false; 4829 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4830 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4831 UseAdaptiveSizePolicy = false; 4832 UseAdaptiveNUMAChunkSizing = false; 4833 } 4834 } 4835 } 4836 if (!UseNUMA && ForceNUMA) { 4837 UseNUMA = true; 4838 } 4839 } 4840 4841 if (MaxFDLimit) { 4842 // set the number of file descriptors to max. print out error 4843 // if getrlimit/setrlimit fails but continue regardless. 4844 struct rlimit nbr_files; 4845 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4846 if (status != 0) { 4847 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 4848 } else { 4849 nbr_files.rlim_cur = nbr_files.rlim_max; 4850 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4851 if (status != 0) { 4852 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 4853 } 4854 } 4855 } 4856 4857 // Initialize lock used to serialize thread creation (see os::create_thread) 4858 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4859 4860 // at-exit methods are called in the reverse order of their registration. 4861 // atexit functions are called on return from main or as a result of a 4862 // call to exit(3C). There can be only 32 of these functions registered 4863 // and atexit() does not set errno. 4864 4865 if (PerfAllowAtExitRegistration) { 4866 // only register atexit functions if PerfAllowAtExitRegistration is set. 4867 // atexit functions can be delayed until process exit time, which 4868 // can be problematic for embedded VM situations. Embedded VMs should 4869 // call DestroyJavaVM() to assure that VM resources are released. 4870 4871 // note: perfMemory_exit_helper atexit function may be removed in 4872 // the future if the appropriate cleanup code can be added to the 4873 // VM_Exit VMOperation's doit method. 4874 if (atexit(perfMemory_exit_helper) != 0) { 4875 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4876 } 4877 } 4878 4879 // initialize thread priority policy 4880 prio_init(); 4881 4882 return JNI_OK; 4883 } 4884 4885 // Mark the polling page as unreadable 4886 void os::make_polling_page_unreadable(void) { 4887 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4888 fatal("Could not disable polling page"); 4889 } 4890 } 4891 4892 // Mark the polling page as readable 4893 void os::make_polling_page_readable(void) { 4894 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4895 fatal("Could not enable polling page"); 4896 } 4897 } 4898 4899 // older glibc versions don't have this macro (which expands to 4900 // an optimized bit-counting function) so we have to roll our own 4901 #ifndef CPU_COUNT 4902 4903 static int _cpu_count(const cpu_set_t* cpus) { 4904 int count = 0; 4905 // only look up to the number of configured processors 4906 for (int i = 0; i < os::processor_count(); i++) { 4907 if (CPU_ISSET(i, cpus)) { 4908 count++; 4909 } 4910 } 4911 return count; 4912 } 4913 4914 #define CPU_COUNT(cpus) _cpu_count(cpus) 4915 4916 #endif // CPU_COUNT 4917 4918 // Get the current number of available processors for this process. 4919 // This value can change at any time during a process's lifetime. 4920 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 4921 // If it appears there may be more than 1024 processors then we do a 4922 // dynamic check - see 6515172 for details. 4923 // If anything goes wrong we fallback to returning the number of online 4924 // processors - which can be greater than the number available to the process. 4925 int os::active_processor_count() { 4926 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 4927 cpu_set_t* cpus_p = &cpus; 4928 int cpus_size = sizeof(cpu_set_t); 4929 4930 int configured_cpus = processor_count(); // upper bound on available cpus 4931 int cpu_count = 0; 4932 4933 // old build platforms may not support dynamic cpu sets 4934 #ifdef CPU_ALLOC 4935 4936 // To enable easy testing of the dynamic path on different platforms we 4937 // introduce a diagnostic flag: UseCpuAllocPath 4938 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 4939 // kernel may use a mask bigger than cpu_set_t 4940 log_trace(os)("active_processor_count: using dynamic path %s" 4941 "- configured processors: %d", 4942 UseCpuAllocPath ? "(forced) " : "", 4943 configured_cpus); 4944 cpus_p = CPU_ALLOC(configured_cpus); 4945 if (cpus_p != NULL) { 4946 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 4947 // zero it just to be safe 4948 CPU_ZERO_S(cpus_size, cpus_p); 4949 } 4950 else { 4951 // failed to allocate so fallback to online cpus 4952 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4953 log_trace(os)("active_processor_count: " 4954 "CPU_ALLOC failed (%s) - using " 4955 "online processor count: %d", 4956 os::strerror(errno), online_cpus); 4957 return online_cpus; 4958 } 4959 } 4960 else { 4961 log_trace(os)("active_processor_count: using static path - configured processors: %d", 4962 configured_cpus); 4963 } 4964 #else // CPU_ALLOC 4965 // these stubs won't be executed 4966 #define CPU_COUNT_S(size, cpus) -1 4967 #define CPU_FREE(cpus) 4968 4969 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 4970 configured_cpus); 4971 #endif // CPU_ALLOC 4972 4973 // pid 0 means the current thread - which we have to assume represents the process 4974 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 4975 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4976 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 4977 } 4978 else { 4979 cpu_count = CPU_COUNT(cpus_p); 4980 } 4981 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 4982 } 4983 else { 4984 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 4985 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 4986 "which may exceed available processors", os::strerror(errno), cpu_count); 4987 } 4988 4989 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4990 CPU_FREE(cpus_p); 4991 } 4992 4993 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 4994 return cpu_count; 4995 } 4996 4997 void os::set_native_thread_name(const char *name) { 4998 if (Linux::_pthread_setname_np) { 4999 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5000 snprintf(buf, sizeof(buf), "%s", name); 5001 buf[sizeof(buf) - 1] = '\0'; 5002 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5003 // ERANGE should not happen; all other errors should just be ignored. 5004 assert(rc != ERANGE, "pthread_setname_np failed"); 5005 } 5006 } 5007 5008 bool os::distribute_processes(uint length, uint* distribution) { 5009 // Not yet implemented. 5010 return false; 5011 } 5012 5013 bool os::bind_to_processor(uint processor_id) { 5014 // Not yet implemented. 5015 return false; 5016 } 5017 5018 /// 5019 5020 void os::SuspendedThreadTask::internal_do_task() { 5021 if (do_suspend(_thread->osthread())) { 5022 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5023 do_task(context); 5024 do_resume(_thread->osthread()); 5025 } 5026 } 5027 5028 class PcFetcher : public os::SuspendedThreadTask { 5029 public: 5030 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 5031 ExtendedPC result(); 5032 protected: 5033 void do_task(const os::SuspendedThreadTaskContext& context); 5034 private: 5035 ExtendedPC _epc; 5036 }; 5037 5038 ExtendedPC PcFetcher::result() { 5039 guarantee(is_done(), "task is not done yet."); 5040 return _epc; 5041 } 5042 5043 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 5044 Thread* thread = context.thread(); 5045 OSThread* osthread = thread->osthread(); 5046 if (osthread->ucontext() != NULL) { 5047 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 5048 } else { 5049 // NULL context is unexpected, double-check this is the VMThread 5050 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 5051 } 5052 } 5053 5054 // Suspends the target using the signal mechanism and then grabs the PC before 5055 // resuming the target. Used by the flat-profiler only 5056 ExtendedPC os::get_thread_pc(Thread* thread) { 5057 // Make sure that it is called by the watcher for the VMThread 5058 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 5059 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 5060 5061 PcFetcher fetcher(thread); 5062 fetcher.run(); 5063 return fetcher.result(); 5064 } 5065 5066 //////////////////////////////////////////////////////////////////////////////// 5067 // debug support 5068 5069 bool os::find(address addr, outputStream* st) { 5070 Dl_info dlinfo; 5071 memset(&dlinfo, 0, sizeof(dlinfo)); 5072 if (dladdr(addr, &dlinfo) != 0) { 5073 st->print(PTR_FORMAT ": ", p2i(addr)); 5074 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5075 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5076 p2i(addr) - p2i(dlinfo.dli_saddr)); 5077 } else if (dlinfo.dli_fbase != NULL) { 5078 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5079 } else { 5080 st->print("<absolute address>"); 5081 } 5082 if (dlinfo.dli_fname != NULL) { 5083 st->print(" in %s", dlinfo.dli_fname); 5084 } 5085 if (dlinfo.dli_fbase != NULL) { 5086 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5087 } 5088 st->cr(); 5089 5090 if (Verbose) { 5091 // decode some bytes around the PC 5092 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5093 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5094 address lowest = (address) dlinfo.dli_sname; 5095 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5096 if (begin < lowest) begin = lowest; 5097 Dl_info dlinfo2; 5098 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5099 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5100 end = (address) dlinfo2.dli_saddr; 5101 } 5102 Disassembler::decode(begin, end, st); 5103 } 5104 return true; 5105 } 5106 return false; 5107 } 5108 5109 //////////////////////////////////////////////////////////////////////////////// 5110 // misc 5111 5112 // This does not do anything on Linux. This is basically a hook for being 5113 // able to use structured exception handling (thread-local exception filters) 5114 // on, e.g., Win32. 5115 void 5116 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5117 JavaCallArguments* args, Thread* thread) { 5118 f(value, method, args, thread); 5119 } 5120 5121 void os::print_statistics() { 5122 } 5123 5124 bool os::message_box(const char* title, const char* message) { 5125 int i; 5126 fdStream err(defaultStream::error_fd()); 5127 for (i = 0; i < 78; i++) err.print_raw("="); 5128 err.cr(); 5129 err.print_raw_cr(title); 5130 for (i = 0; i < 78; i++) err.print_raw("-"); 5131 err.cr(); 5132 err.print_raw_cr(message); 5133 for (i = 0; i < 78; i++) err.print_raw("="); 5134 err.cr(); 5135 5136 char buf[16]; 5137 // Prevent process from exiting upon "read error" without consuming all CPU 5138 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5139 5140 return buf[0] == 'y' || buf[0] == 'Y'; 5141 } 5142 5143 int os::stat(const char *path, struct stat *sbuf) { 5144 char pathbuf[MAX_PATH]; 5145 if (strlen(path) > MAX_PATH - 1) { 5146 errno = ENAMETOOLONG; 5147 return -1; 5148 } 5149 os::native_path(strcpy(pathbuf, path)); 5150 return ::stat(pathbuf, sbuf); 5151 } 5152 5153 // Is a (classpath) directory empty? 5154 bool os::dir_is_empty(const char* path) { 5155 DIR *dir = NULL; 5156 struct dirent *ptr; 5157 5158 dir = opendir(path); 5159 if (dir == NULL) return true; 5160 5161 // Scan the directory 5162 bool result = true; 5163 char buf[sizeof(struct dirent) + MAX_PATH]; 5164 while (result && (ptr = ::readdir(dir)) != NULL) { 5165 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5166 result = false; 5167 } 5168 } 5169 closedir(dir); 5170 return result; 5171 } 5172 5173 // This code originates from JDK's sysOpen and open64_w 5174 // from src/solaris/hpi/src/system_md.c 5175 5176 int os::open(const char *path, int oflag, int mode) { 5177 if (strlen(path) > MAX_PATH - 1) { 5178 errno = ENAMETOOLONG; 5179 return -1; 5180 } 5181 5182 // All file descriptors that are opened in the Java process and not 5183 // specifically destined for a subprocess should have the close-on-exec 5184 // flag set. If we don't set it, then careless 3rd party native code 5185 // might fork and exec without closing all appropriate file descriptors 5186 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5187 // turn might: 5188 // 5189 // - cause end-of-file to fail to be detected on some file 5190 // descriptors, resulting in mysterious hangs, or 5191 // 5192 // - might cause an fopen in the subprocess to fail on a system 5193 // suffering from bug 1085341. 5194 // 5195 // (Yes, the default setting of the close-on-exec flag is a Unix 5196 // design flaw) 5197 // 5198 // See: 5199 // 1085341: 32-bit stdio routines should support file descriptors >255 5200 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5201 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5202 // 5203 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5204 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5205 // because it saves a system call and removes a small window where the flag 5206 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5207 // and we fall back to using FD_CLOEXEC (see below). 5208 #ifdef O_CLOEXEC 5209 oflag |= O_CLOEXEC; 5210 #endif 5211 5212 int fd = ::open64(path, oflag, mode); 5213 if (fd == -1) return -1; 5214 5215 //If the open succeeded, the file might still be a directory 5216 { 5217 struct stat64 buf64; 5218 int ret = ::fstat64(fd, &buf64); 5219 int st_mode = buf64.st_mode; 5220 5221 if (ret != -1) { 5222 if ((st_mode & S_IFMT) == S_IFDIR) { 5223 errno = EISDIR; 5224 ::close(fd); 5225 return -1; 5226 } 5227 } else { 5228 ::close(fd); 5229 return -1; 5230 } 5231 } 5232 5233 #ifdef FD_CLOEXEC 5234 // Validate that the use of the O_CLOEXEC flag on open above worked. 5235 // With recent kernels, we will perform this check exactly once. 5236 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5237 if (!O_CLOEXEC_is_known_to_work) { 5238 int flags = ::fcntl(fd, F_GETFD); 5239 if (flags != -1) { 5240 if ((flags & FD_CLOEXEC) != 0) 5241 O_CLOEXEC_is_known_to_work = 1; 5242 else 5243 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5244 } 5245 } 5246 #endif 5247 5248 return fd; 5249 } 5250 5251 5252 // create binary file, rewriting existing file if required 5253 int os::create_binary_file(const char* path, bool rewrite_existing) { 5254 int oflags = O_WRONLY | O_CREAT; 5255 if (!rewrite_existing) { 5256 oflags |= O_EXCL; 5257 } 5258 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5259 } 5260 5261 // return current position of file pointer 5262 jlong os::current_file_offset(int fd) { 5263 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5264 } 5265 5266 // move file pointer to the specified offset 5267 jlong os::seek_to_file_offset(int fd, jlong offset) { 5268 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5269 } 5270 5271 // This code originates from JDK's sysAvailable 5272 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5273 5274 int os::available(int fd, jlong *bytes) { 5275 jlong cur, end; 5276 int mode; 5277 struct stat64 buf64; 5278 5279 if (::fstat64(fd, &buf64) >= 0) { 5280 mode = buf64.st_mode; 5281 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5282 int n; 5283 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5284 *bytes = n; 5285 return 1; 5286 } 5287 } 5288 } 5289 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5290 return 0; 5291 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5292 return 0; 5293 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5294 return 0; 5295 } 5296 *bytes = end - cur; 5297 return 1; 5298 } 5299 5300 // Map a block of memory. 5301 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5302 char *addr, size_t bytes, bool read_only, 5303 bool allow_exec) { 5304 int prot; 5305 int flags = MAP_PRIVATE; 5306 5307 if (read_only) { 5308 prot = PROT_READ; 5309 } else { 5310 prot = PROT_READ | PROT_WRITE; 5311 } 5312 5313 if (allow_exec) { 5314 prot |= PROT_EXEC; 5315 } 5316 5317 if (addr != NULL) { 5318 flags |= MAP_FIXED; 5319 } 5320 5321 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5322 fd, file_offset); 5323 if (mapped_address == MAP_FAILED) { 5324 return NULL; 5325 } 5326 return mapped_address; 5327 } 5328 5329 5330 // Remap a block of memory. 5331 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5332 char *addr, size_t bytes, bool read_only, 5333 bool allow_exec) { 5334 // same as map_memory() on this OS 5335 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5336 allow_exec); 5337 } 5338 5339 5340 // Unmap a block of memory. 5341 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5342 return munmap(addr, bytes) == 0; 5343 } 5344 5345 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5346 5347 static clockid_t thread_cpu_clockid(Thread* thread) { 5348 pthread_t tid = thread->osthread()->pthread_id(); 5349 clockid_t clockid; 5350 5351 // Get thread clockid 5352 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5353 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5354 return clockid; 5355 } 5356 5357 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5358 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5359 // of a thread. 5360 // 5361 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5362 // the fast estimate available on the platform. 5363 5364 jlong os::current_thread_cpu_time() { 5365 if (os::Linux::supports_fast_thread_cpu_time()) { 5366 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5367 } else { 5368 // return user + sys since the cost is the same 5369 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5370 } 5371 } 5372 5373 jlong os::thread_cpu_time(Thread* thread) { 5374 // consistent with what current_thread_cpu_time() returns 5375 if (os::Linux::supports_fast_thread_cpu_time()) { 5376 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5377 } else { 5378 return slow_thread_cpu_time(thread, true /* user + sys */); 5379 } 5380 } 5381 5382 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5383 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5384 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5385 } else { 5386 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5387 } 5388 } 5389 5390 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5391 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5392 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5393 } else { 5394 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5395 } 5396 } 5397 5398 // -1 on error. 5399 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5400 pid_t tid = thread->osthread()->thread_id(); 5401 char *s; 5402 char stat[2048]; 5403 int statlen; 5404 char proc_name[64]; 5405 int count; 5406 long sys_time, user_time; 5407 char cdummy; 5408 int idummy; 5409 long ldummy; 5410 FILE *fp; 5411 5412 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5413 fp = fopen(proc_name, "r"); 5414 if (fp == NULL) return -1; 5415 statlen = fread(stat, 1, 2047, fp); 5416 stat[statlen] = '\0'; 5417 fclose(fp); 5418 5419 // Skip pid and the command string. Note that we could be dealing with 5420 // weird command names, e.g. user could decide to rename java launcher 5421 // to "java 1.4.2 :)", then the stat file would look like 5422 // 1234 (java 1.4.2 :)) R ... ... 5423 // We don't really need to know the command string, just find the last 5424 // occurrence of ")" and then start parsing from there. See bug 4726580. 5425 s = strrchr(stat, ')'); 5426 if (s == NULL) return -1; 5427 5428 // Skip blank chars 5429 do { s++; } while (s && isspace(*s)); 5430 5431 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5432 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5433 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5434 &user_time, &sys_time); 5435 if (count != 13) return -1; 5436 if (user_sys_cpu_time) { 5437 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5438 } else { 5439 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5440 } 5441 } 5442 5443 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5444 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5445 info_ptr->may_skip_backward = false; // elapsed time not wall time 5446 info_ptr->may_skip_forward = false; // elapsed time not wall time 5447 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5448 } 5449 5450 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5451 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5452 info_ptr->may_skip_backward = false; // elapsed time not wall time 5453 info_ptr->may_skip_forward = false; // elapsed time not wall time 5454 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5455 } 5456 5457 bool os::is_thread_cpu_time_supported() { 5458 return true; 5459 } 5460 5461 // System loadavg support. Returns -1 if load average cannot be obtained. 5462 // Linux doesn't yet have a (official) notion of processor sets, 5463 // so just return the system wide load average. 5464 int os::loadavg(double loadavg[], int nelem) { 5465 return ::getloadavg(loadavg, nelem); 5466 } 5467 5468 void os::pause() { 5469 char filename[MAX_PATH]; 5470 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5471 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5472 } else { 5473 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5474 } 5475 5476 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5477 if (fd != -1) { 5478 struct stat buf; 5479 ::close(fd); 5480 while (::stat(filename, &buf) == 0) { 5481 (void)::poll(NULL, 0, 100); 5482 } 5483 } else { 5484 jio_fprintf(stderr, 5485 "Could not open pause file '%s', continuing immediately.\n", filename); 5486 } 5487 } 5488 5489 5490 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5491 // comment paragraphs are worth repeating here: 5492 // 5493 // Assumption: 5494 // Only one parker can exist on an event, which is why we allocate 5495 // them per-thread. Multiple unparkers can coexist. 5496 // 5497 // _Event serves as a restricted-range semaphore. 5498 // -1 : thread is blocked, i.e. there is a waiter 5499 // 0 : neutral: thread is running or ready, 5500 // could have been signaled after a wait started 5501 // 1 : signaled - thread is running or ready 5502 // 5503 5504 // utility to compute the abstime argument to timedwait: 5505 // millis is the relative timeout time 5506 // abstime will be the absolute timeout time 5507 // TODO: replace compute_abstime() with unpackTime() 5508 5509 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5510 if (millis < 0) millis = 0; 5511 5512 jlong seconds = millis / 1000; 5513 millis %= 1000; 5514 if (seconds > 50000000) { // see man cond_timedwait(3T) 5515 seconds = 50000000; 5516 } 5517 5518 if (os::supports_monotonic_clock()) { 5519 struct timespec now; 5520 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5521 assert_status(status == 0, status, "clock_gettime"); 5522 abstime->tv_sec = now.tv_sec + seconds; 5523 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5524 if (nanos >= NANOSECS_PER_SEC) { 5525 abstime->tv_sec += 1; 5526 nanos -= NANOSECS_PER_SEC; 5527 } 5528 abstime->tv_nsec = nanos; 5529 } else { 5530 struct timeval now; 5531 int status = gettimeofday(&now, NULL); 5532 assert(status == 0, "gettimeofday"); 5533 abstime->tv_sec = now.tv_sec + seconds; 5534 long usec = now.tv_usec + millis * 1000; 5535 if (usec >= 1000000) { 5536 abstime->tv_sec += 1; 5537 usec -= 1000000; 5538 } 5539 abstime->tv_nsec = usec * 1000; 5540 } 5541 return abstime; 5542 } 5543 5544 void os::PlatformEvent::park() { // AKA "down()" 5545 // Transitions for _Event: 5546 // -1 => -1 : illegal 5547 // 1 => 0 : pass - return immediately 5548 // 0 => -1 : block; then set _Event to 0 before returning 5549 5550 // Invariant: Only the thread associated with the Event/PlatformEvent 5551 // may call park(). 5552 // TODO: assert that _Assoc != NULL or _Assoc == Self 5553 assert(_nParked == 0, "invariant"); 5554 5555 int v; 5556 for (;;) { 5557 v = _Event; 5558 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5559 } 5560 guarantee(v >= 0, "invariant"); 5561 if (v == 0) { 5562 // Do this the hard way by blocking ... 5563 int status = pthread_mutex_lock(_mutex); 5564 assert_status(status == 0, status, "mutex_lock"); 5565 guarantee(_nParked == 0, "invariant"); 5566 ++_nParked; 5567 while (_Event < 0) { 5568 status = pthread_cond_wait(_cond, _mutex); 5569 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5570 // Treat this the same as if the wait was interrupted 5571 if (status == ETIME) { status = EINTR; } 5572 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5573 } 5574 --_nParked; 5575 5576 _Event = 0; 5577 status = pthread_mutex_unlock(_mutex); 5578 assert_status(status == 0, status, "mutex_unlock"); 5579 // Paranoia to ensure our locked and lock-free paths interact 5580 // correctly with each other. 5581 OrderAccess::fence(); 5582 } 5583 guarantee(_Event >= 0, "invariant"); 5584 } 5585 5586 int os::PlatformEvent::park(jlong millis) { 5587 // Transitions for _Event: 5588 // -1 => -1 : illegal 5589 // 1 => 0 : pass - return immediately 5590 // 0 => -1 : block; then set _Event to 0 before returning 5591 5592 guarantee(_nParked == 0, "invariant"); 5593 5594 int v; 5595 for (;;) { 5596 v = _Event; 5597 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5598 } 5599 guarantee(v >= 0, "invariant"); 5600 if (v != 0) return OS_OK; 5601 5602 // We do this the hard way, by blocking the thread. 5603 // Consider enforcing a minimum timeout value. 5604 struct timespec abst; 5605 compute_abstime(&abst, millis); 5606 5607 int ret = OS_TIMEOUT; 5608 int status = pthread_mutex_lock(_mutex); 5609 assert_status(status == 0, status, "mutex_lock"); 5610 guarantee(_nParked == 0, "invariant"); 5611 ++_nParked; 5612 5613 // Object.wait(timo) will return because of 5614 // (a) notification 5615 // (b) timeout 5616 // (c) thread.interrupt 5617 // 5618 // Thread.interrupt and object.notify{All} both call Event::set. 5619 // That is, we treat thread.interrupt as a special case of notification. 5620 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5621 // We assume all ETIME returns are valid. 5622 // 5623 // TODO: properly differentiate simultaneous notify+interrupt. 5624 // In that case, we should propagate the notify to another waiter. 5625 5626 while (_Event < 0) { 5627 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5628 assert_status(status == 0 || status == EINTR || 5629 status == ETIME || status == ETIMEDOUT, 5630 status, "cond_timedwait"); 5631 if (!FilterSpuriousWakeups) break; // previous semantics 5632 if (status == ETIME || status == ETIMEDOUT) break; 5633 // We consume and ignore EINTR and spurious wakeups. 5634 } 5635 --_nParked; 5636 if (_Event >= 0) { 5637 ret = OS_OK; 5638 } 5639 _Event = 0; 5640 status = pthread_mutex_unlock(_mutex); 5641 assert_status(status == 0, status, "mutex_unlock"); 5642 assert(_nParked == 0, "invariant"); 5643 // Paranoia to ensure our locked and lock-free paths interact 5644 // correctly with each other. 5645 OrderAccess::fence(); 5646 return ret; 5647 } 5648 5649 void os::PlatformEvent::unpark() { 5650 // Transitions for _Event: 5651 // 0 => 1 : just return 5652 // 1 => 1 : just return 5653 // -1 => either 0 or 1; must signal target thread 5654 // That is, we can safely transition _Event from -1 to either 5655 // 0 or 1. 5656 // See also: "Semaphores in Plan 9" by Mullender & Cox 5657 // 5658 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5659 // that it will take two back-to-back park() calls for the owning 5660 // thread to block. This has the benefit of forcing a spurious return 5661 // from the first park() call after an unpark() call which will help 5662 // shake out uses of park() and unpark() without condition variables. 5663 5664 if (Atomic::xchg(1, &_Event) >= 0) return; 5665 5666 // Wait for the thread associated with the event to vacate 5667 int status = pthread_mutex_lock(_mutex); 5668 assert_status(status == 0, status, "mutex_lock"); 5669 int AnyWaiters = _nParked; 5670 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5671 status = pthread_mutex_unlock(_mutex); 5672 assert_status(status == 0, status, "mutex_unlock"); 5673 if (AnyWaiters != 0) { 5674 // Note that we signal() *after* dropping the lock for "immortal" Events. 5675 // This is safe and avoids a common class of futile wakeups. In rare 5676 // circumstances this can cause a thread to return prematurely from 5677 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5678 // will simply re-test the condition and re-park itself. 5679 // This provides particular benefit if the underlying platform does not 5680 // provide wait morphing. 5681 status = pthread_cond_signal(_cond); 5682 assert_status(status == 0, status, "cond_signal"); 5683 } 5684 } 5685 5686 5687 // JSR166 5688 // ------------------------------------------------------- 5689 5690 // The solaris and linux implementations of park/unpark are fairly 5691 // conservative for now, but can be improved. They currently use a 5692 // mutex/condvar pair, plus a a count. 5693 // Park decrements count if > 0, else does a condvar wait. Unpark 5694 // sets count to 1 and signals condvar. Only one thread ever waits 5695 // on the condvar. Contention seen when trying to park implies that someone 5696 // is unparking you, so don't wait. And spurious returns are fine, so there 5697 // is no need to track notifications. 5698 5699 // This code is common to linux and solaris and will be moved to a 5700 // common place in dolphin. 5701 // 5702 // The passed in time value is either a relative time in nanoseconds 5703 // or an absolute time in milliseconds. Either way it has to be unpacked 5704 // into suitable seconds and nanoseconds components and stored in the 5705 // given timespec structure. 5706 // Given time is a 64-bit value and the time_t used in the timespec is only 5707 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5708 // overflow if times way in the future are given. Further on Solaris versions 5709 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5710 // number of seconds, in abstime, is less than current_time + 100,000,000. 5711 // As it will be 28 years before "now + 100000000" will overflow we can 5712 // ignore overflow and just impose a hard-limit on seconds using the value 5713 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5714 // years from "now". 5715 5716 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5717 assert(time > 0, "convertTime"); 5718 time_t max_secs = 0; 5719 5720 if (!os::supports_monotonic_clock() || isAbsolute) { 5721 struct timeval now; 5722 int status = gettimeofday(&now, NULL); 5723 assert(status == 0, "gettimeofday"); 5724 5725 max_secs = now.tv_sec + MAX_SECS; 5726 5727 if (isAbsolute) { 5728 jlong secs = time / 1000; 5729 if (secs > max_secs) { 5730 absTime->tv_sec = max_secs; 5731 } else { 5732 absTime->tv_sec = secs; 5733 } 5734 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5735 } else { 5736 jlong secs = time / NANOSECS_PER_SEC; 5737 if (secs >= MAX_SECS) { 5738 absTime->tv_sec = max_secs; 5739 absTime->tv_nsec = 0; 5740 } else { 5741 absTime->tv_sec = now.tv_sec + secs; 5742 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5743 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5744 absTime->tv_nsec -= NANOSECS_PER_SEC; 5745 ++absTime->tv_sec; // note: this must be <= max_secs 5746 } 5747 } 5748 } 5749 } else { 5750 // must be relative using monotonic clock 5751 struct timespec now; 5752 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5753 assert_status(status == 0, status, "clock_gettime"); 5754 max_secs = now.tv_sec + MAX_SECS; 5755 jlong secs = time / NANOSECS_PER_SEC; 5756 if (secs >= MAX_SECS) { 5757 absTime->tv_sec = max_secs; 5758 absTime->tv_nsec = 0; 5759 } else { 5760 absTime->tv_sec = now.tv_sec + secs; 5761 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5762 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5763 absTime->tv_nsec -= NANOSECS_PER_SEC; 5764 ++absTime->tv_sec; // note: this must be <= max_secs 5765 } 5766 } 5767 } 5768 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5769 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5770 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5771 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5772 } 5773 5774 void Parker::park(bool isAbsolute, jlong time) { 5775 // Ideally we'd do something useful while spinning, such 5776 // as calling unpackTime(). 5777 5778 // Optional fast-path check: 5779 // Return immediately if a permit is available. 5780 // We depend on Atomic::xchg() having full barrier semantics 5781 // since we are doing a lock-free update to _counter. 5782 if (Atomic::xchg(0, &_counter) > 0) return; 5783 5784 Thread* thread = Thread::current(); 5785 assert(thread->is_Java_thread(), "Must be JavaThread"); 5786 JavaThread *jt = (JavaThread *)thread; 5787 5788 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5789 // Check interrupt before trying to wait 5790 if (Thread::is_interrupted(thread, false)) { 5791 return; 5792 } 5793 5794 // Next, demultiplex/decode time arguments 5795 timespec absTime; 5796 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5797 return; 5798 } 5799 if (time > 0) { 5800 unpackTime(&absTime, isAbsolute, time); 5801 } 5802 5803 5804 // Enter safepoint region 5805 // Beware of deadlocks such as 6317397. 5806 // The per-thread Parker:: mutex is a classic leaf-lock. 5807 // In particular a thread must never block on the Threads_lock while 5808 // holding the Parker:: mutex. If safepoints are pending both the 5809 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5810 ThreadBlockInVM tbivm(jt); 5811 5812 // Don't wait if cannot get lock since interference arises from 5813 // unblocking. Also. check interrupt before trying wait 5814 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5815 return; 5816 } 5817 5818 int status; 5819 if (_counter > 0) { // no wait needed 5820 _counter = 0; 5821 status = pthread_mutex_unlock(_mutex); 5822 assert_status(status == 0, status, "invariant"); 5823 // Paranoia to ensure our locked and lock-free paths interact 5824 // correctly with each other and Java-level accesses. 5825 OrderAccess::fence(); 5826 return; 5827 } 5828 5829 #ifdef ASSERT 5830 // Don't catch signals while blocked; let the running threads have the signals. 5831 // (This allows a debugger to break into the running thread.) 5832 sigset_t oldsigs; 5833 sigemptyset(&oldsigs); 5834 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5835 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5836 #endif 5837 5838 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5839 jt->set_suspend_equivalent(); 5840 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5841 5842 assert(_cur_index == -1, "invariant"); 5843 if (time == 0) { 5844 _cur_index = REL_INDEX; // arbitrary choice when not timed 5845 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5846 } else { 5847 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5848 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5849 } 5850 _cur_index = -1; 5851 assert_status(status == 0 || status == EINTR || 5852 status == ETIME || status == ETIMEDOUT, 5853 status, "cond_timedwait"); 5854 5855 #ifdef ASSERT 5856 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5857 #endif 5858 5859 _counter = 0; 5860 status = pthread_mutex_unlock(_mutex); 5861 assert_status(status == 0, status, "invariant"); 5862 // Paranoia to ensure our locked and lock-free paths interact 5863 // correctly with each other and Java-level accesses. 5864 OrderAccess::fence(); 5865 5866 // If externally suspended while waiting, re-suspend 5867 if (jt->handle_special_suspend_equivalent_condition()) { 5868 jt->java_suspend_self(); 5869 } 5870 } 5871 5872 void Parker::unpark() { 5873 int status = pthread_mutex_lock(_mutex); 5874 assert_status(status == 0, status, "invariant"); 5875 const int s = _counter; 5876 _counter = 1; 5877 // must capture correct index before unlocking 5878 int index = _cur_index; 5879 status = pthread_mutex_unlock(_mutex); 5880 assert_status(status == 0, status, "invariant"); 5881 if (s < 1 && index != -1) { 5882 // thread is definitely parked 5883 status = pthread_cond_signal(&_cond[index]); 5884 assert_status(status == 0, status, "invariant"); 5885 } 5886 } 5887 5888 5889 extern char** environ; 5890 5891 // Run the specified command in a separate process. Return its exit value, 5892 // or -1 on failure (e.g. can't fork a new process). 5893 // Unlike system(), this function can be called from signal handler. It 5894 // doesn't block SIGINT et al. 5895 int os::fork_and_exec(char* cmd) { 5896 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5897 5898 pid_t pid = fork(); 5899 5900 if (pid < 0) { 5901 // fork failed 5902 return -1; 5903 5904 } else if (pid == 0) { 5905 // child process 5906 5907 execve("/bin/sh", (char* const*)argv, environ); 5908 5909 // execve failed 5910 _exit(-1); 5911 5912 } else { 5913 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5914 // care about the actual exit code, for now. 5915 5916 int status; 5917 5918 // Wait for the child process to exit. This returns immediately if 5919 // the child has already exited. */ 5920 while (waitpid(pid, &status, 0) < 0) { 5921 switch (errno) { 5922 case ECHILD: return 0; 5923 case EINTR: break; 5924 default: return -1; 5925 } 5926 } 5927 5928 if (WIFEXITED(status)) { 5929 // The child exited normally; get its exit code. 5930 return WEXITSTATUS(status); 5931 } else if (WIFSIGNALED(status)) { 5932 // The child exited because of a signal 5933 // The best value to return is 0x80 + signal number, 5934 // because that is what all Unix shells do, and because 5935 // it allows callers to distinguish between process exit and 5936 // process death by signal. 5937 return 0x80 + WTERMSIG(status); 5938 } else { 5939 // Unknown exit code; pass it through 5940 return status; 5941 } 5942 } 5943 } 5944 5945 // is_headless_jre() 5946 // 5947 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5948 // in order to report if we are running in a headless jre 5949 // 5950 // Since JDK8 xawt/libmawt.so was moved into the same directory 5951 // as libawt.so, and renamed libawt_xawt.so 5952 // 5953 bool os::is_headless_jre() { 5954 struct stat statbuf; 5955 char buf[MAXPATHLEN]; 5956 char libmawtpath[MAXPATHLEN]; 5957 const char *xawtstr = "/xawt/libmawt.so"; 5958 const char *new_xawtstr = "/libawt_xawt.so"; 5959 char *p; 5960 5961 // Get path to libjvm.so 5962 os::jvm_path(buf, sizeof(buf)); 5963 5964 // Get rid of libjvm.so 5965 p = strrchr(buf, '/'); 5966 if (p == NULL) { 5967 return false; 5968 } else { 5969 *p = '\0'; 5970 } 5971 5972 // Get rid of client or server 5973 p = strrchr(buf, '/'); 5974 if (p == NULL) { 5975 return false; 5976 } else { 5977 *p = '\0'; 5978 } 5979 5980 // check xawt/libmawt.so 5981 strcpy(libmawtpath, buf); 5982 strcat(libmawtpath, xawtstr); 5983 if (::stat(libmawtpath, &statbuf) == 0) return false; 5984 5985 // check libawt_xawt.so 5986 strcpy(libmawtpath, buf); 5987 strcat(libmawtpath, new_xawtstr); 5988 if (::stat(libmawtpath, &statbuf) == 0) return false; 5989 5990 return true; 5991 } 5992 5993 // Get the default path to the core file 5994 // Returns the length of the string 5995 int os::get_core_path(char* buffer, size_t bufferSize) { 5996 /* 5997 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5998 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5999 */ 6000 const int core_pattern_len = 129; 6001 char core_pattern[core_pattern_len] = {0}; 6002 6003 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 6004 if (core_pattern_file == -1) { 6005 return -1; 6006 } 6007 6008 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 6009 ::close(core_pattern_file); 6010 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 6011 return -1; 6012 } 6013 if (core_pattern[ret-1] == '\n') { 6014 core_pattern[ret-1] = '\0'; 6015 } else { 6016 core_pattern[ret] = '\0'; 6017 } 6018 6019 char *pid_pos = strstr(core_pattern, "%p"); 6020 int written; 6021 6022 if (core_pattern[0] == '/') { 6023 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 6024 } else { 6025 char cwd[PATH_MAX]; 6026 6027 const char* p = get_current_directory(cwd, PATH_MAX); 6028 if (p == NULL) { 6029 return -1; 6030 } 6031 6032 if (core_pattern[0] == '|') { 6033 written = jio_snprintf(buffer, bufferSize, 6034 "\"%s\" (or dumping to %s/core.%d)", 6035 &core_pattern[1], p, current_process_id()); 6036 } else { 6037 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 6038 } 6039 } 6040 6041 if (written < 0) { 6042 return -1; 6043 } 6044 6045 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 6046 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 6047 6048 if (core_uses_pid_file != -1) { 6049 char core_uses_pid = 0; 6050 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 6051 ::close(core_uses_pid_file); 6052 6053 if (core_uses_pid == '1') { 6054 jio_snprintf(buffer + written, bufferSize - written, 6055 ".%d", current_process_id()); 6056 } 6057 } 6058 } 6059 6060 return strlen(buffer); 6061 } 6062 6063 bool os::start_debugging(char *buf, int buflen) { 6064 int len = (int)strlen(buf); 6065 char *p = &buf[len]; 6066 6067 jio_snprintf(p, buflen-len, 6068 "\n\n" 6069 "Do you want to debug the problem?\n\n" 6070 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6071 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6072 "Otherwise, press RETURN to abort...", 6073 os::current_process_id(), os::current_process_id(), 6074 os::current_thread_id(), os::current_thread_id()); 6075 6076 bool yes = os::message_box("Unexpected Error", buf); 6077 6078 if (yes) { 6079 // yes, user asked VM to launch debugger 6080 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 6081 os::current_process_id(), os::current_process_id()); 6082 6083 os::fork_and_exec(buf); 6084 yes = false; 6085 } 6086 return yes; 6087 } 6088 6089 6090 // Java/Compiler thread: 6091 // 6092 // Low memory addresses 6093 // P0 +------------------------+ 6094 // | |\ Java thread created by VM does not have glibc 6095 // | glibc guard page | - guard page, attached Java thread usually has 6096 // | |/ 1 page glibc guard. 6097 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6098 // | |\ 6099 // | HotSpot Guard Pages | - red, yellow and reserved pages 6100 // | |/ 6101 // +------------------------+ JavaThread::stack_reserved_zone_base() 6102 // | |\ 6103 // | Normal Stack | - 6104 // | |/ 6105 // P2 +------------------------+ Thread::stack_base() 6106 // 6107 // Non-Java thread: 6108 // 6109 // Low memory addresses 6110 // P0 +------------------------+ 6111 // | |\ 6112 // | glibc guard page | - usually 1 page 6113 // | |/ 6114 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6115 // | |\ 6116 // | Normal Stack | - 6117 // | |/ 6118 // P2 +------------------------+ Thread::stack_base() 6119 // 6120 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 6121 // returned from pthread_attr_getstack(). 6122 // ** Due to NPTL implementation error, linux takes the glibc guard page out 6123 // of the stack size given in pthread_attr. We work around this for 6124 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 6125 // 6126 #ifndef ZERO 6127 static void current_stack_region(address * bottom, size_t * size) { 6128 if (os::Linux::is_initial_thread()) { 6129 // initial thread needs special handling because pthread_getattr_np() 6130 // may return bogus value. 6131 *bottom = os::Linux::initial_thread_stack_bottom(); 6132 *size = os::Linux::initial_thread_stack_size(); 6133 } else { 6134 pthread_attr_t attr; 6135 6136 int rslt = pthread_getattr_np(pthread_self(), &attr); 6137 6138 // JVM needs to know exact stack location, abort if it fails 6139 if (rslt != 0) { 6140 if (rslt == ENOMEM) { 6141 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 6142 } else { 6143 fatal("pthread_getattr_np failed with errno = %d", rslt); 6144 } 6145 } 6146 6147 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 6148 fatal("Cannot locate current stack attributes!"); 6149 } 6150 6151 // Work around NPTL stack guard error. 6152 size_t guard_size = 0; 6153 rslt = pthread_attr_getguardsize(&attr, &guard_size); 6154 if (rslt != 0) { 6155 fatal("pthread_attr_getguardsize failed with errno = %d", rslt); 6156 } 6157 *bottom += guard_size; 6158 *size -= guard_size; 6159 6160 pthread_attr_destroy(&attr); 6161 6162 } 6163 assert(os::current_stack_pointer() >= *bottom && 6164 os::current_stack_pointer() < *bottom + *size, "just checking"); 6165 } 6166 6167 address os::current_stack_base() { 6168 address bottom; 6169 size_t size; 6170 current_stack_region(&bottom, &size); 6171 return (bottom + size); 6172 } 6173 6174 size_t os::current_stack_size() { 6175 // This stack size includes the usable stack and HotSpot guard pages 6176 // (for the threads that have Hotspot guard pages). 6177 address bottom; 6178 size_t size; 6179 current_stack_region(&bottom, &size); 6180 return size; 6181 } 6182 #endif 6183 6184 static inline struct timespec get_mtime(const char* filename) { 6185 struct stat st; 6186 int ret = os::stat(filename, &st); 6187 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 6188 return st.st_mtim; 6189 } 6190 6191 int os::compare_file_modified_times(const char* file1, const char* file2) { 6192 struct timespec filetime1 = get_mtime(file1); 6193 struct timespec filetime2 = get_mtime(file2); 6194 int diff = filetime1.tv_sec - filetime2.tv_sec; 6195 if (diff == 0) { 6196 return filetime1.tv_nsec - filetime2.tv_nsec; 6197 } 6198 return diff; 6199 } 6200 6201 /////////////// Unit tests /////////////// 6202 6203 #ifndef PRODUCT 6204 6205 #define test_log(...) \ 6206 do { \ 6207 if (VerboseInternalVMTests) { \ 6208 tty->print_cr(__VA_ARGS__); \ 6209 tty->flush(); \ 6210 } \ 6211 } while (false) 6212 6213 class TestReserveMemorySpecial : AllStatic { 6214 public: 6215 static void small_page_write(void* addr, size_t size) { 6216 size_t page_size = os::vm_page_size(); 6217 6218 char* end = (char*)addr + size; 6219 for (char* p = (char*)addr; p < end; p += page_size) { 6220 *p = 1; 6221 } 6222 } 6223 6224 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6225 if (!UseHugeTLBFS) { 6226 return; 6227 } 6228 6229 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6230 6231 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6232 6233 if (addr != NULL) { 6234 small_page_write(addr, size); 6235 6236 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6237 } 6238 } 6239 6240 static void test_reserve_memory_special_huge_tlbfs_only() { 6241 if (!UseHugeTLBFS) { 6242 return; 6243 } 6244 6245 size_t lp = os::large_page_size(); 6246 6247 for (size_t size = lp; size <= lp * 10; size += lp) { 6248 test_reserve_memory_special_huge_tlbfs_only(size); 6249 } 6250 } 6251 6252 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6253 size_t lp = os::large_page_size(); 6254 size_t ag = os::vm_allocation_granularity(); 6255 6256 // sizes to test 6257 const size_t sizes[] = { 6258 lp, lp + ag, lp + lp / 2, lp * 2, 6259 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6260 lp * 10, lp * 10 + lp / 2 6261 }; 6262 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6263 6264 // For each size/alignment combination, we test three scenarios: 6265 // 1) with req_addr == NULL 6266 // 2) with a non-null req_addr at which we expect to successfully allocate 6267 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6268 // expect the allocation to either fail or to ignore req_addr 6269 6270 // Pre-allocate two areas; they shall be as large as the largest allocation 6271 // and aligned to the largest alignment we will be testing. 6272 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6273 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6274 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6275 -1, 0); 6276 assert(mapping1 != MAP_FAILED, "should work"); 6277 6278 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6279 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6280 -1, 0); 6281 assert(mapping2 != MAP_FAILED, "should work"); 6282 6283 // Unmap the first mapping, but leave the second mapping intact: the first 6284 // mapping will serve as a value for a "good" req_addr (case 2). The second 6285 // mapping, still intact, as "bad" req_addr (case 3). 6286 ::munmap(mapping1, mapping_size); 6287 6288 // Case 1 6289 test_log("%s, req_addr NULL:", __FUNCTION__); 6290 test_log("size align result"); 6291 6292 for (int i = 0; i < num_sizes; i++) { 6293 const size_t size = sizes[i]; 6294 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6295 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6296 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6297 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6298 if (p != NULL) { 6299 assert(is_ptr_aligned(p, alignment), "must be"); 6300 small_page_write(p, size); 6301 os::Linux::release_memory_special_huge_tlbfs(p, size); 6302 } 6303 } 6304 } 6305 6306 // Case 2 6307 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6308 test_log("size align req_addr result"); 6309 6310 for (int i = 0; i < num_sizes; i++) { 6311 const size_t size = sizes[i]; 6312 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6313 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6314 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6315 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6316 size, alignment, p2i(req_addr), p2i(p), 6317 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6318 if (p != NULL) { 6319 assert(p == req_addr, "must be"); 6320 small_page_write(p, size); 6321 os::Linux::release_memory_special_huge_tlbfs(p, size); 6322 } 6323 } 6324 } 6325 6326 // Case 3 6327 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6328 test_log("size align req_addr result"); 6329 6330 for (int i = 0; i < num_sizes; i++) { 6331 const size_t size = sizes[i]; 6332 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6333 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6334 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6335 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6336 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6337 // as the area around req_addr contains already existing mappings, the API should always 6338 // return NULL (as per contract, it cannot return another address) 6339 assert(p == NULL, "must be"); 6340 } 6341 } 6342 6343 ::munmap(mapping2, mapping_size); 6344 6345 } 6346 6347 static void test_reserve_memory_special_huge_tlbfs() { 6348 if (!UseHugeTLBFS) { 6349 return; 6350 } 6351 6352 test_reserve_memory_special_huge_tlbfs_only(); 6353 test_reserve_memory_special_huge_tlbfs_mixed(); 6354 } 6355 6356 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6357 if (!UseSHM) { 6358 return; 6359 } 6360 6361 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6362 6363 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6364 6365 if (addr != NULL) { 6366 assert(is_ptr_aligned(addr, alignment), "Check"); 6367 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6368 6369 small_page_write(addr, size); 6370 6371 os::Linux::release_memory_special_shm(addr, size); 6372 } 6373 } 6374 6375 static void test_reserve_memory_special_shm() { 6376 size_t lp = os::large_page_size(); 6377 size_t ag = os::vm_allocation_granularity(); 6378 6379 for (size_t size = ag; size < lp * 3; size += ag) { 6380 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6381 test_reserve_memory_special_shm(size, alignment); 6382 } 6383 } 6384 } 6385 6386 static void test() { 6387 test_reserve_memory_special_huge_tlbfs(); 6388 test_reserve_memory_special_shm(); 6389 } 6390 }; 6391 6392 void TestReserveMemorySpecial_test() { 6393 TestReserveMemorySpecial::test(); 6394 } 6395 6396 #endif