1 /* 2 * Copyright (c) 1999, 2014, 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 "memory/allocation.inline.hpp" 36 #include "memory/filemap.hpp" 37 #include "mutex_linux.inline.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_share_linux.hpp" 40 #include "prims/jniFastGetField.hpp" 41 #include "prims/jvm.h" 42 #include "prims/jvm_misc.hpp" 43 #include "runtime/arguments.hpp" 44 #include "runtime/extendedPC.hpp" 45 #include "runtime/globals.hpp" 46 #include "runtime/interfaceSupport.hpp" 47 #include "runtime/init.hpp" 48 #include "runtime/java.hpp" 49 #include "runtime/javaCalls.hpp" 50 #include "runtime/mutexLocker.hpp" 51 #include "runtime/objectMonitor.hpp" 52 #include "runtime/orderAccess.inline.hpp" 53 #include "runtime/osThread.hpp" 54 #include "runtime/perfMemory.hpp" 55 #include "runtime/sharedRuntime.hpp" 56 #include "runtime/statSampler.hpp" 57 #include "runtime/stubRoutines.hpp" 58 #include "runtime/thread.inline.hpp" 59 #include "runtime/threadCritical.hpp" 60 #include "runtime/timer.hpp" 61 #include "services/attachListener.hpp" 62 #include "services/memTracker.hpp" 63 #include "services/runtimeService.hpp" 64 #include "utilities/decoder.hpp" 65 #include "utilities/defaultStream.hpp" 66 #include "utilities/events.hpp" 67 #include "utilities/elfFile.hpp" 68 #include "utilities/growableArray.hpp" 69 #include "utilities/vmError.hpp" 70 71 // put OS-includes here 72 # include <sys/types.h> 73 # include <sys/mman.h> 74 # include <sys/stat.h> 75 # include <sys/select.h> 76 # include <pthread.h> 77 # include <signal.h> 78 # include <errno.h> 79 # include <dlfcn.h> 80 # include <stdio.h> 81 # include <unistd.h> 82 # include <sys/resource.h> 83 # include <pthread.h> 84 # include <sys/stat.h> 85 # include <sys/time.h> 86 # include <sys/times.h> 87 # include <sys/utsname.h> 88 # include <sys/socket.h> 89 # include <sys/wait.h> 90 # include <pwd.h> 91 # include <poll.h> 92 # include <semaphore.h> 93 # include <fcntl.h> 94 # include <string.h> 95 # include <syscall.h> 96 # include <sys/sysinfo.h> 97 # include <gnu/libc-version.h> 98 # include <sys/ipc.h> 99 # include <sys/shm.h> 100 # include <link.h> 101 # include <stdint.h> 102 # include <inttypes.h> 103 # include <sys/ioctl.h> 104 105 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 106 107 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 108 // getrusage() is prepared to handle the associated failure. 109 #ifndef RUSAGE_THREAD 110 #define RUSAGE_THREAD (1) /* only the calling thread */ 111 #endif 112 113 #define MAX_PATH (2 * K) 114 115 #define MAX_SECS 100000000 116 117 // for timer info max values which include all bits 118 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 119 120 #define LARGEPAGES_BIT (1 << 6) 121 //////////////////////////////////////////////////////////////////////////////// 122 // global variables 123 julong os::Linux::_physical_memory = 0; 124 125 address os::Linux::_initial_thread_stack_bottom = NULL; 126 uintptr_t os::Linux::_initial_thread_stack_size = 0; 127 128 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 129 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 130 Mutex* os::Linux::_createThread_lock = NULL; 131 pthread_t os::Linux::_main_thread; 132 int os::Linux::_page_size = -1; 133 const int os::Linux::_vm_default_page_size = (8 * K); 134 bool os::Linux::_is_floating_stack = false; 135 bool os::Linux::_is_NPTL = false; 136 bool os::Linux::_supports_fast_thread_cpu_time = false; 137 const char * os::Linux::_glibc_version = NULL; 138 const char * os::Linux::_libpthread_version = NULL; 139 pthread_condattr_t os::Linux::_condattr[1]; 140 141 static jlong initial_time_count=0; 142 143 static int clock_tics_per_sec = 100; 144 145 // For diagnostics to print a message once. see run_periodic_checks 146 static sigset_t check_signal_done; 147 static bool check_signals = true; 148 149 static pid_t _initial_pid = 0; 150 151 /* Signal number used to suspend/resume a thread */ 152 153 /* do not use any signal number less than SIGSEGV, see 4355769 */ 154 static int SR_signum = SIGUSR2; 155 sigset_t SR_sigset; 156 157 /* Used to protect dlsym() calls */ 158 static pthread_mutex_t dl_mutex; 159 160 // Declarations 161 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 162 163 #ifdef JAVASE_EMBEDDED 164 class MemNotifyThread: public Thread { 165 friend class VMStructs; 166 public: 167 virtual void run(); 168 169 private: 170 static MemNotifyThread* _memnotify_thread; 171 int _fd; 172 173 public: 174 175 // Constructor 176 MemNotifyThread(int fd); 177 178 // Tester 179 bool is_memnotify_thread() const { return true; } 180 181 // Printing 182 char* name() const { return (char*)"Linux MemNotify Thread"; } 183 184 // Returns the single instance of the MemNotifyThread 185 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; } 186 187 // Create and start the single instance of MemNotifyThread 188 static void start(); 189 }; 190 #endif // JAVASE_EMBEDDED 191 192 // utility functions 193 194 static int SR_initialize(); 195 196 julong os::available_memory() { 197 return Linux::available_memory(); 198 } 199 200 julong os::Linux::available_memory() { 201 // values in struct sysinfo are "unsigned long" 202 struct sysinfo si; 203 sysinfo(&si); 204 205 return (julong)si.freeram * si.mem_unit; 206 } 207 208 julong os::physical_memory() { 209 return Linux::physical_memory(); 210 } 211 212 //////////////////////////////////////////////////////////////////////////////// 213 // environment support 214 215 bool os::getenv(const char* name, char* buf, int len) { 216 const char* val = ::getenv(name); 217 if (val != NULL && strlen(val) < (size_t)len) { 218 strcpy(buf, val); 219 return true; 220 } 221 if (len > 0) buf[0] = 0; // return a null string 222 return false; 223 } 224 225 226 // Return true if user is running as root. 227 228 bool os::have_special_privileges() { 229 static bool init = false; 230 static bool privileges = false; 231 if (!init) { 232 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 233 init = true; 234 } 235 return privileges; 236 } 237 238 239 #ifndef SYS_gettid 240 // i386: 224, ia64: 1105, amd64: 186, sparc 143 241 #ifdef __ia64__ 242 #define SYS_gettid 1105 243 #elif __i386__ 244 #define SYS_gettid 224 245 #elif __amd64__ 246 #define SYS_gettid 186 247 #elif __sparc__ 248 #define SYS_gettid 143 249 #else 250 #error define gettid for the arch 251 #endif 252 #endif 253 254 // Cpu architecture string 255 static char cpu_arch[] = HOTSPOT_LIB_ARCH; 256 257 // pid_t gettid() 258 // 259 // Returns the kernel thread id of the currently running thread. Kernel 260 // thread id is used to access /proc. 261 // 262 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 263 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 264 // 265 pid_t os::Linux::gettid() { 266 int rslt = syscall(SYS_gettid); 267 if (rslt == -1) { 268 // old kernel, no NPTL support 269 return getpid(); 270 } else { 271 return (pid_t)rslt; 272 } 273 } 274 275 // Most versions of linux have a bug where the number of processors are 276 // determined by looking at the /proc file system. In a chroot environment, 277 // the system call returns 1. This causes the VM to act as if it is 278 // a single processor and elide locking (see is_MP() call). 279 static bool unsafe_chroot_detected = false; 280 static const char *unstable_chroot_error = "/proc file system not found.\n" 281 "Java may be unstable running multithreaded in a chroot " 282 "environment on Linux when /proc filesystem is not mounted."; 283 284 void os::Linux::initialize_system_info() { 285 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 286 if (processor_count() == 1) { 287 pid_t pid = os::Linux::gettid(); 288 char fname[32]; 289 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 290 FILE *fp = fopen(fname, "r"); 291 if (fp == NULL) { 292 unsafe_chroot_detected = true; 293 } else { 294 fclose(fp); 295 } 296 } 297 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 298 assert(processor_count() > 0, "linux error"); 299 } 300 301 void os::init_system_properties_values() { 302 // The next steps are taken in the product version: 303 // 304 // Obtain the JAVA_HOME value from the location of libjvm.so. 305 // This library should be located at: 306 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 307 // 308 // If "/jre/lib/" appears at the right place in the path, then we 309 // assume libjvm.so is installed in a JDK and we use this path. 310 // 311 // Otherwise exit with message: "Could not create the Java virtual machine." 312 // 313 // The following extra steps are taken in the debugging version: 314 // 315 // If "/jre/lib/" does NOT appear at the right place in the path 316 // instead of exit check for $JAVA_HOME environment variable. 317 // 318 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 319 // then we append a fake suffix "hotspot/libjvm.so" to this path so 320 // it looks like libjvm.so is installed there 321 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 322 // 323 // Otherwise exit. 324 // 325 // Important note: if the location of libjvm.so changes this 326 // code needs to be changed accordingly. 327 328 // See ld(1): 329 // The linker uses the following search paths to locate required 330 // shared libraries: 331 // 1: ... 332 // ... 333 // 7: The default directories, normally /lib and /usr/lib. 334 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 335 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 336 #else 337 #define DEFAULT_LIBPATH "/lib:/usr/lib" 338 #endif 339 340 // Base path of extensions installed on the system. 341 #define SYS_EXT_DIR "/usr/java/packages" 342 #define EXTENSIONS_DIR "/lib/ext" 343 #define ENDORSED_DIR "/lib/endorsed" 344 345 // Buffer that fits several sprintfs. 346 // Note that the space for the colon and the trailing null are provided 347 // by the nulls included by the sizeof operator. 348 const size_t bufsize = 349 MAX3((size_t)MAXPATHLEN, // For dll_dir & friends. 350 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR), // extensions dir 351 (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir 352 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 353 354 // sysclasspath, java_home, dll_dir 355 { 356 char *pslash; 357 os::jvm_path(buf, bufsize); 358 359 // Found the full path to libjvm.so. 360 // Now cut the path to <java_home>/jre if we can. 361 *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so. 362 pslash = strrchr(buf, '/'); 363 if (pslash != NULL) { 364 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 365 } 366 Arguments::set_dll_dir(buf); 367 368 if (pslash != NULL) { 369 pslash = strrchr(buf, '/'); 370 if (pslash != NULL) { 371 *pslash = '\0'; // Get rid of /<arch>. 372 pslash = strrchr(buf, '/'); 373 if (pslash != NULL) { 374 *pslash = '\0'; // Get rid of /lib. 375 } 376 } 377 } 378 Arguments::set_java_home(buf); 379 set_boot_path('/', ':'); 380 } 381 382 // Where to look for native libraries. 383 // 384 // Note: Due to a legacy implementation, most of the library path 385 // is set in the launcher. This was to accomodate linking restrictions 386 // on legacy Linux implementations (which are no longer supported). 387 // Eventually, all the library path setting will be done here. 388 // 389 // However, to prevent the proliferation of improperly built native 390 // libraries, the new path component /usr/java/packages is added here. 391 // Eventually, all the library path setting will be done here. 392 { 393 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 394 // should always exist (until the legacy problem cited above is 395 // addressed). 396 const char *v = ::getenv("LD_LIBRARY_PATH"); 397 const char *v_colon = ":"; 398 if (v == NULL) { v = ""; v_colon = ""; } 399 // That's +1 for the colon and +1 for the trailing '\0'. 400 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 401 strlen(v) + 1 + 402 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 403 mtInternal); 404 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 405 Arguments::set_library_path(ld_library_path); 406 FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal); 407 } 408 409 // Extensions directories. 410 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 411 Arguments::set_ext_dirs(buf); 412 413 // Endorsed standards default directory. 414 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 415 Arguments::set_endorsed_dirs(buf); 416 417 FREE_C_HEAP_ARRAY(char, buf, mtInternal); 418 419 #undef DEFAULT_LIBPATH 420 #undef SYS_EXT_DIR 421 #undef EXTENSIONS_DIR 422 #undef ENDORSED_DIR 423 } 424 425 //////////////////////////////////////////////////////////////////////////////// 426 // breakpoint support 427 428 void os::breakpoint() { 429 BREAKPOINT; 430 } 431 432 extern "C" void breakpoint() { 433 // use debugger to set breakpoint here 434 } 435 436 //////////////////////////////////////////////////////////////////////////////// 437 // signal support 438 439 debug_only(static bool signal_sets_initialized = false); 440 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 441 442 bool os::Linux::is_sig_ignored(int sig) { 443 struct sigaction oact; 444 sigaction(sig, (struct sigaction*)NULL, &oact); 445 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 446 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 447 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 448 return true; 449 else 450 return false; 451 } 452 453 void os::Linux::signal_sets_init() { 454 // Should also have an assertion stating we are still single-threaded. 455 assert(!signal_sets_initialized, "Already initialized"); 456 // Fill in signals that are necessarily unblocked for all threads in 457 // the VM. Currently, we unblock the following signals: 458 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 459 // by -Xrs (=ReduceSignalUsage)); 460 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 461 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 462 // the dispositions or masks wrt these signals. 463 // Programs embedding the VM that want to use the above signals for their 464 // own purposes must, at this time, use the "-Xrs" option to prevent 465 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 466 // (See bug 4345157, and other related bugs). 467 // In reality, though, unblocking these signals is really a nop, since 468 // these signals are not blocked by default. 469 sigemptyset(&unblocked_sigs); 470 sigemptyset(&allowdebug_blocked_sigs); 471 sigaddset(&unblocked_sigs, SIGILL); 472 sigaddset(&unblocked_sigs, SIGSEGV); 473 sigaddset(&unblocked_sigs, SIGBUS); 474 sigaddset(&unblocked_sigs, SIGFPE); 475 #if defined(PPC64) 476 sigaddset(&unblocked_sigs, SIGTRAP); 477 #endif 478 sigaddset(&unblocked_sigs, SR_signum); 479 480 if (!ReduceSignalUsage) { 481 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 482 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 483 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 484 } 485 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 486 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 487 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 488 } 489 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 490 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 491 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 492 } 493 } 494 // Fill in signals that are blocked by all but the VM thread. 495 sigemptyset(&vm_sigs); 496 if (!ReduceSignalUsage) 497 sigaddset(&vm_sigs, BREAK_SIGNAL); 498 debug_only(signal_sets_initialized = true); 499 500 } 501 502 // These are signals that are unblocked while a thread is running Java. 503 // (For some reason, they get blocked by default.) 504 sigset_t* os::Linux::unblocked_signals() { 505 assert(signal_sets_initialized, "Not initialized"); 506 return &unblocked_sigs; 507 } 508 509 // These are the signals that are blocked while a (non-VM) thread is 510 // running Java. Only the VM thread handles these signals. 511 sigset_t* os::Linux::vm_signals() { 512 assert(signal_sets_initialized, "Not initialized"); 513 return &vm_sigs; 514 } 515 516 // These are signals that are blocked during cond_wait to allow debugger in 517 sigset_t* os::Linux::allowdebug_blocked_signals() { 518 assert(signal_sets_initialized, "Not initialized"); 519 return &allowdebug_blocked_sigs; 520 } 521 522 void os::Linux::hotspot_sigmask(Thread* thread) { 523 524 //Save caller's signal mask before setting VM signal mask 525 sigset_t caller_sigmask; 526 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 527 528 OSThread* osthread = thread->osthread(); 529 osthread->set_caller_sigmask(caller_sigmask); 530 531 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 532 533 if (!ReduceSignalUsage) { 534 if (thread->is_VM_thread()) { 535 // Only the VM thread handles BREAK_SIGNAL ... 536 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 537 } else { 538 // ... all other threads block BREAK_SIGNAL 539 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 540 } 541 } 542 } 543 544 ////////////////////////////////////////////////////////////////////////////// 545 // detecting pthread library 546 547 void os::Linux::libpthread_init() { 548 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 549 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 550 // generic name for earlier versions. 551 // Define macros here so we can build HotSpot on old systems. 552 # ifndef _CS_GNU_LIBC_VERSION 553 # define _CS_GNU_LIBC_VERSION 2 554 # endif 555 # ifndef _CS_GNU_LIBPTHREAD_VERSION 556 # define _CS_GNU_LIBPTHREAD_VERSION 3 557 # endif 558 559 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 560 if (n > 0) { 561 char *str = (char *)malloc(n, mtInternal); 562 confstr(_CS_GNU_LIBC_VERSION, str, n); 563 os::Linux::set_glibc_version(str); 564 } else { 565 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 566 static char _gnu_libc_version[32]; 567 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 568 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 569 os::Linux::set_glibc_version(_gnu_libc_version); 570 } 571 572 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 573 if (n > 0) { 574 char *str = (char *)malloc(n, mtInternal); 575 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 576 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 577 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 578 // is the case. LinuxThreads has a hard limit on max number of threads. 579 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 580 // On the other hand, NPTL does not have such a limit, sysconf() 581 // will return -1 and errno is not changed. Check if it is really NPTL. 582 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 583 strstr(str, "NPTL") && 584 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 585 free(str); 586 os::Linux::set_libpthread_version("linuxthreads"); 587 } else { 588 os::Linux::set_libpthread_version(str); 589 } 590 } else { 591 // glibc before 2.3.2 only has LinuxThreads. 592 os::Linux::set_libpthread_version("linuxthreads"); 593 } 594 595 if (strstr(libpthread_version(), "NPTL")) { 596 os::Linux::set_is_NPTL(); 597 } else { 598 os::Linux::set_is_LinuxThreads(); 599 } 600 601 // LinuxThreads have two flavors: floating-stack mode, which allows variable 602 // stack size; and fixed-stack mode. NPTL is always floating-stack. 603 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 604 os::Linux::set_is_floating_stack(); 605 } 606 } 607 608 ///////////////////////////////////////////////////////////////////////////// 609 // thread stack 610 611 // Force Linux kernel to expand current thread stack. If "bottom" is close 612 // to the stack guard, caller should block all signals. 613 // 614 // MAP_GROWSDOWN: 615 // A special mmap() flag that is used to implement thread stacks. It tells 616 // kernel that the memory region should extend downwards when needed. This 617 // allows early versions of LinuxThreads to only mmap the first few pages 618 // when creating a new thread. Linux kernel will automatically expand thread 619 // stack as needed (on page faults). 620 // 621 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 622 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 623 // region, it's hard to tell if the fault is due to a legitimate stack 624 // access or because of reading/writing non-exist memory (e.g. buffer 625 // overrun). As a rule, if the fault happens below current stack pointer, 626 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 627 // application (see Linux kernel fault.c). 628 // 629 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 630 // stack overflow detection. 631 // 632 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 633 // not use this flag. However, the stack of initial thread is not created 634 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 635 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 636 // and then attach the thread to JVM. 637 // 638 // To get around the problem and allow stack banging on Linux, we need to 639 // manually expand thread stack after receiving the SIGSEGV. 640 // 641 // There are two ways to expand thread stack to address "bottom", we used 642 // both of them in JVM before 1.5: 643 // 1. adjust stack pointer first so that it is below "bottom", and then 644 // touch "bottom" 645 // 2. mmap() the page in question 646 // 647 // Now alternate signal stack is gone, it's harder to use 2. For instance, 648 // if current sp is already near the lower end of page 101, and we need to 649 // call mmap() to map page 100, it is possible that part of the mmap() frame 650 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 651 // That will destroy the mmap() frame and cause VM to crash. 652 // 653 // The following code works by adjusting sp first, then accessing the "bottom" 654 // page to force a page fault. Linux kernel will then automatically expand the 655 // stack mapping. 656 // 657 // _expand_stack_to() assumes its frame size is less than page size, which 658 // should always be true if the function is not inlined. 659 660 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 661 #define NOINLINE 662 #else 663 #define NOINLINE __attribute__ ((noinline)) 664 #endif 665 666 static void _expand_stack_to(address bottom) NOINLINE; 667 668 static void _expand_stack_to(address bottom) { 669 address sp; 670 size_t size; 671 volatile char *p; 672 673 // Adjust bottom to point to the largest address within the same page, it 674 // gives us a one-page buffer if alloca() allocates slightly more memory. 675 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 676 bottom += os::Linux::page_size() - 1; 677 678 // sp might be slightly above current stack pointer; if that's the case, we 679 // will alloca() a little more space than necessary, which is OK. Don't use 680 // os::current_stack_pointer(), as its result can be slightly below current 681 // stack pointer, causing us to not alloca enough to reach "bottom". 682 sp = (address)&sp; 683 684 if (sp > bottom) { 685 size = sp - bottom; 686 p = (volatile char *)alloca(size); 687 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 688 p[0] = '\0'; 689 } 690 } 691 692 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 693 assert(t!=NULL, "just checking"); 694 assert(t->osthread()->expanding_stack(), "expand should be set"); 695 assert(t->stack_base() != NULL, "stack_base was not initialized"); 696 697 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 698 sigset_t mask_all, old_sigset; 699 sigfillset(&mask_all); 700 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 701 _expand_stack_to(addr); 702 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 703 return true; 704 } 705 return false; 706 } 707 708 ////////////////////////////////////////////////////////////////////////////// 709 // create new thread 710 711 static address highest_vm_reserved_address(); 712 713 // check if it's safe to start a new thread 714 static bool _thread_safety_check(Thread* thread) { 715 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 716 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 717 // Heap is mmap'ed at lower end of memory space. Thread stacks are 718 // allocated (MAP_FIXED) from high address space. Every thread stack 719 // occupies a fixed size slot (usually 2Mbytes, but user can change 720 // it to other values if they rebuild LinuxThreads). 721 // 722 // Problem with MAP_FIXED is that mmap() can still succeed even part of 723 // the memory region has already been mmap'ed. That means if we have too 724 // many threads and/or very large heap, eventually thread stack will 725 // collide with heap. 726 // 727 // Here we try to prevent heap/stack collision by comparing current 728 // stack bottom with the highest address that has been mmap'ed by JVM 729 // plus a safety margin for memory maps created by native code. 730 // 731 // This feature can be disabled by setting ThreadSafetyMargin to 0 732 // 733 if (ThreadSafetyMargin > 0) { 734 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 735 736 // not safe if our stack extends below the safety margin 737 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 738 } else { 739 return true; 740 } 741 } else { 742 // Floating stack LinuxThreads or NPTL: 743 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 744 // there's not enough space left, pthread_create() will fail. If we come 745 // here, that means enough space has been reserved for stack. 746 return true; 747 } 748 } 749 750 // Thread start routine for all newly created threads 751 static void *java_start(Thread *thread) { 752 // Try to randomize the cache line index of hot stack frames. 753 // This helps when threads of the same stack traces evict each other's 754 // cache lines. The threads can be either from the same JVM instance, or 755 // from different JVM instances. The benefit is especially true for 756 // processors with hyperthreading technology. 757 static int counter = 0; 758 int pid = os::current_process_id(); 759 alloca(((pid ^ counter++) & 7) * 128); 760 761 ThreadLocalStorage::set_thread(thread); 762 763 OSThread* osthread = thread->osthread(); 764 Monitor* sync = osthread->startThread_lock(); 765 766 // non floating stack LinuxThreads needs extra check, see above 767 if (!_thread_safety_check(thread)) { 768 // notify parent thread 769 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 770 osthread->set_state(ZOMBIE); 771 sync->notify_all(); 772 return NULL; 773 } 774 775 // thread_id is kernel thread id (similar to Solaris LWP id) 776 osthread->set_thread_id(os::Linux::gettid()); 777 778 if (UseNUMA) { 779 int lgrp_id = os::numa_get_group_id(); 780 if (lgrp_id != -1) { 781 thread->set_lgrp_id(lgrp_id); 782 } 783 } 784 // initialize signal mask for this thread 785 os::Linux::hotspot_sigmask(thread); 786 787 // initialize floating point control register 788 os::Linux::init_thread_fpu_state(); 789 790 // handshaking with parent thread 791 { 792 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 793 794 // notify parent thread 795 osthread->set_state(INITIALIZED); 796 sync->notify_all(); 797 798 // wait until os::start_thread() 799 while (osthread->get_state() == INITIALIZED) { 800 sync->wait(Mutex::_no_safepoint_check_flag); 801 } 802 } 803 804 // call one more level start routine 805 thread->run(); 806 807 return 0; 808 } 809 810 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 811 assert(thread->osthread() == NULL, "caller responsible"); 812 813 // Allocate the OSThread object 814 OSThread* osthread = new OSThread(NULL, NULL); 815 if (osthread == NULL) { 816 return false; 817 } 818 819 // set the correct thread state 820 osthread->set_thread_type(thr_type); 821 822 // Initial state is ALLOCATED but not INITIALIZED 823 osthread->set_state(ALLOCATED); 824 825 thread->set_osthread(osthread); 826 827 // init thread attributes 828 pthread_attr_t attr; 829 pthread_attr_init(&attr); 830 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 831 832 // stack size 833 if (os::Linux::supports_variable_stack_size()) { 834 // calculate stack size if it's not specified by caller 835 if (stack_size == 0) { 836 stack_size = os::Linux::default_stack_size(thr_type); 837 838 switch (thr_type) { 839 case os::java_thread: 840 // Java threads use ThreadStackSize which default value can be 841 // changed with the flag -Xss 842 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 843 stack_size = JavaThread::stack_size_at_create(); 844 break; 845 case os::compiler_thread: 846 if (CompilerThreadStackSize > 0) { 847 stack_size = (size_t)(CompilerThreadStackSize * K); 848 break; 849 } // else fall through: 850 // use VMThreadStackSize if CompilerThreadStackSize is not defined 851 case os::vm_thread: 852 case os::pgc_thread: 853 case os::cgc_thread: 854 case os::watcher_thread: 855 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 856 break; 857 } 858 } 859 860 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 861 pthread_attr_setstacksize(&attr, stack_size); 862 } else { 863 // let pthread_create() pick the default value. 864 } 865 866 // glibc guard page 867 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 868 869 ThreadState state; 870 871 { 872 // Serialize thread creation if we are running with fixed stack LinuxThreads 873 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 874 if (lock) { 875 os::Linux::createThread_lock()->lock_without_safepoint_check(); 876 } 877 878 pthread_t tid; 879 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 880 881 pthread_attr_destroy(&attr); 882 883 if (ret != 0) { 884 if (PrintMiscellaneous && (Verbose || WizardMode)) { 885 perror("pthread_create()"); 886 } 887 // Need to clean up stuff we've allocated so far 888 thread->set_osthread(NULL); 889 delete osthread; 890 if (lock) os::Linux::createThread_lock()->unlock(); 891 return false; 892 } 893 894 // Store pthread info into the OSThread 895 osthread->set_pthread_id(tid); 896 897 // Wait until child thread is either initialized or aborted 898 { 899 Monitor* sync_with_child = osthread->startThread_lock(); 900 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 901 while ((state = osthread->get_state()) == ALLOCATED) { 902 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 903 } 904 } 905 906 if (lock) { 907 os::Linux::createThread_lock()->unlock(); 908 } 909 } 910 911 // Aborted due to thread limit being reached 912 if (state == ZOMBIE) { 913 thread->set_osthread(NULL); 914 delete osthread; 915 return false; 916 } 917 918 // The thread is returned suspended (in state INITIALIZED), 919 // and is started higher up in the call chain 920 assert(state == INITIALIZED, "race condition"); 921 return true; 922 } 923 924 ///////////////////////////////////////////////////////////////////////////// 925 // attach existing thread 926 927 // bootstrap the main thread 928 bool os::create_main_thread(JavaThread* thread) { 929 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 930 return create_attached_thread(thread); 931 } 932 933 bool os::create_attached_thread(JavaThread* thread) { 934 #ifdef ASSERT 935 thread->verify_not_published(); 936 #endif 937 938 // Allocate the OSThread object 939 OSThread* osthread = new OSThread(NULL, NULL); 940 941 if (osthread == NULL) { 942 return false; 943 } 944 945 // Store pthread info into the OSThread 946 osthread->set_thread_id(os::Linux::gettid()); 947 osthread->set_pthread_id(::pthread_self()); 948 949 // initialize floating point control register 950 os::Linux::init_thread_fpu_state(); 951 952 // Initial thread state is RUNNABLE 953 osthread->set_state(RUNNABLE); 954 955 thread->set_osthread(osthread); 956 957 if (UseNUMA) { 958 int lgrp_id = os::numa_get_group_id(); 959 if (lgrp_id != -1) { 960 thread->set_lgrp_id(lgrp_id); 961 } 962 } 963 964 if (os::Linux::is_initial_thread()) { 965 // If current thread is initial thread, its stack is mapped on demand, 966 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 967 // the entire stack region to avoid SEGV in stack banging. 968 // It is also useful to get around the heap-stack-gap problem on SuSE 969 // kernel (see 4821821 for details). We first expand stack to the top 970 // of yellow zone, then enable stack yellow zone (order is significant, 971 // enabling yellow zone first will crash JVM on SuSE Linux), so there 972 // is no gap between the last two virtual memory regions. 973 974 JavaThread *jt = (JavaThread *)thread; 975 address addr = jt->stack_yellow_zone_base(); 976 assert(addr != NULL, "initialization problem?"); 977 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 978 979 osthread->set_expanding_stack(); 980 os::Linux::manually_expand_stack(jt, addr); 981 osthread->clear_expanding_stack(); 982 } 983 984 // initialize signal mask for this thread 985 // and save the caller's signal mask 986 os::Linux::hotspot_sigmask(thread); 987 988 return true; 989 } 990 991 void os::pd_start_thread(Thread* thread) { 992 OSThread * osthread = thread->osthread(); 993 assert(osthread->get_state() != INITIALIZED, "just checking"); 994 Monitor* sync_with_child = osthread->startThread_lock(); 995 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 996 sync_with_child->notify(); 997 } 998 999 // Free Linux resources related to the OSThread 1000 void os::free_thread(OSThread* osthread) { 1001 assert(osthread != NULL, "osthread not set"); 1002 1003 if (Thread::current()->osthread() == osthread) { 1004 // Restore caller's signal mask 1005 sigset_t sigmask = osthread->caller_sigmask(); 1006 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1007 } 1008 1009 delete osthread; 1010 } 1011 1012 ////////////////////////////////////////////////////////////////////////////// 1013 // thread local storage 1014 1015 // Restore the thread pointer if the destructor is called. This is in case 1016 // someone from JNI code sets up a destructor with pthread_key_create to run 1017 // detachCurrentThread on thread death. Unless we restore the thread pointer we 1018 // will hang or crash. When detachCurrentThread is called the key will be set 1019 // to null and we will not be called again. If detachCurrentThread is never 1020 // called we could loop forever depending on the pthread implementation. 1021 static void restore_thread_pointer(void* p) { 1022 Thread* thread = (Thread*) p; 1023 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread); 1024 } 1025 1026 int os::allocate_thread_local_storage() { 1027 pthread_key_t key; 1028 int rslt = pthread_key_create(&key, restore_thread_pointer); 1029 assert(rslt == 0, "cannot allocate thread local storage"); 1030 return (int)key; 1031 } 1032 1033 // Note: This is currently not used by VM, as we don't destroy TLS key 1034 // on VM exit. 1035 void os::free_thread_local_storage(int index) { 1036 int rslt = pthread_key_delete((pthread_key_t)index); 1037 assert(rslt == 0, "invalid index"); 1038 } 1039 1040 void os::thread_local_storage_at_put(int index, void* value) { 1041 int rslt = pthread_setspecific((pthread_key_t)index, value); 1042 assert(rslt == 0, "pthread_setspecific failed"); 1043 } 1044 1045 extern "C" Thread* get_thread() { 1046 return ThreadLocalStorage::thread(); 1047 } 1048 1049 ////////////////////////////////////////////////////////////////////////////// 1050 // initial thread 1051 1052 // Check if current thread is the initial thread, similar to Solaris thr_main. 1053 bool os::Linux::is_initial_thread(void) { 1054 char dummy; 1055 // If called before init complete, thread stack bottom will be null. 1056 // Can be called if fatal error occurs before initialization. 1057 if (initial_thread_stack_bottom() == NULL) return false; 1058 assert(initial_thread_stack_bottom() != NULL && 1059 initial_thread_stack_size() != 0, 1060 "os::init did not locate initial thread's stack region"); 1061 if ((address)&dummy >= initial_thread_stack_bottom() && 1062 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1063 return true; 1064 else return false; 1065 } 1066 1067 // Find the virtual memory area that contains addr 1068 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1069 FILE *fp = fopen("/proc/self/maps", "r"); 1070 if (fp) { 1071 address low, high; 1072 while (!feof(fp)) { 1073 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1074 if (low <= addr && addr < high) { 1075 if (vma_low) *vma_low = low; 1076 if (vma_high) *vma_high = high; 1077 fclose (fp); 1078 return true; 1079 } 1080 } 1081 for (;;) { 1082 int ch = fgetc(fp); 1083 if (ch == EOF || ch == (int)'\n') break; 1084 } 1085 } 1086 fclose(fp); 1087 } 1088 return false; 1089 } 1090 1091 // Locate initial thread stack. This special handling of initial thread stack 1092 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1093 // bogus value for initial thread. 1094 void os::Linux::capture_initial_stack(size_t max_size) { 1095 // stack size is the easy part, get it from RLIMIT_STACK 1096 size_t stack_size; 1097 struct rlimit rlim; 1098 getrlimit(RLIMIT_STACK, &rlim); 1099 stack_size = rlim.rlim_cur; 1100 1101 // 6308388: a bug in ld.so will relocate its own .data section to the 1102 // lower end of primordial stack; reduce ulimit -s value a little bit 1103 // so we won't install guard page on ld.so's data section. 1104 stack_size -= 2 * page_size(); 1105 1106 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1107 // 7.1, in both cases we will get 2G in return value. 1108 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1109 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1110 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1111 // in case other parts in glibc still assumes 2M max stack size. 1112 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1113 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1114 if (stack_size > 2 * K * K IA64_ONLY(*2)) 1115 stack_size = 2 * K * K IA64_ONLY(*2); 1116 // Try to figure out where the stack base (top) is. This is harder. 1117 // 1118 // When an application is started, glibc saves the initial stack pointer in 1119 // a global variable "__libc_stack_end", which is then used by system 1120 // libraries. __libc_stack_end should be pretty close to stack top. The 1121 // variable is available since the very early days. However, because it is 1122 // a private interface, it could disappear in the future. 1123 // 1124 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1125 // to __libc_stack_end, it is very close to stack top, but isn't the real 1126 // stack top. Note that /proc may not exist if VM is running as a chroot 1127 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1128 // /proc/<pid>/stat could change in the future (though unlikely). 1129 // 1130 // We try __libc_stack_end first. If that doesn't work, look for 1131 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1132 // as a hint, which should work well in most cases. 1133 1134 uintptr_t stack_start; 1135 1136 // try __libc_stack_end first 1137 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1138 if (p && *p) { 1139 stack_start = *p; 1140 } else { 1141 // see if we can get the start_stack field from /proc/self/stat 1142 FILE *fp; 1143 int pid; 1144 char state; 1145 int ppid; 1146 int pgrp; 1147 int session; 1148 int nr; 1149 int tpgrp; 1150 unsigned long flags; 1151 unsigned long minflt; 1152 unsigned long cminflt; 1153 unsigned long majflt; 1154 unsigned long cmajflt; 1155 unsigned long utime; 1156 unsigned long stime; 1157 long cutime; 1158 long cstime; 1159 long prio; 1160 long nice; 1161 long junk; 1162 long it_real; 1163 uintptr_t start; 1164 uintptr_t vsize; 1165 intptr_t rss; 1166 uintptr_t rsslim; 1167 uintptr_t scodes; 1168 uintptr_t ecode; 1169 int i; 1170 1171 // Figure what the primordial thread stack base is. Code is inspired 1172 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1173 // followed by command name surrounded by parentheses, state, etc. 1174 char stat[2048]; 1175 int statlen; 1176 1177 fp = fopen("/proc/self/stat", "r"); 1178 if (fp) { 1179 statlen = fread(stat, 1, 2047, fp); 1180 stat[statlen] = '\0'; 1181 fclose(fp); 1182 1183 // Skip pid and the command string. Note that we could be dealing with 1184 // weird command names, e.g. user could decide to rename java launcher 1185 // to "java 1.4.2 :)", then the stat file would look like 1186 // 1234 (java 1.4.2 :)) R ... ... 1187 // We don't really need to know the command string, just find the last 1188 // occurrence of ")" and then start parsing from there. See bug 4726580. 1189 char * s = strrchr(stat, ')'); 1190 1191 i = 0; 1192 if (s) { 1193 // Skip blank chars 1194 do s++; while (isspace(*s)); 1195 1196 #define _UFM UINTX_FORMAT 1197 #define _DFM INTX_FORMAT 1198 1199 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1200 /* 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 */ 1201 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, 1202 &state, /* 3 %c */ 1203 &ppid, /* 4 %d */ 1204 &pgrp, /* 5 %d */ 1205 &session, /* 6 %d */ 1206 &nr, /* 7 %d */ 1207 &tpgrp, /* 8 %d */ 1208 &flags, /* 9 %lu */ 1209 &minflt, /* 10 %lu */ 1210 &cminflt, /* 11 %lu */ 1211 &majflt, /* 12 %lu */ 1212 &cmajflt, /* 13 %lu */ 1213 &utime, /* 14 %lu */ 1214 &stime, /* 15 %lu */ 1215 &cutime, /* 16 %ld */ 1216 &cstime, /* 17 %ld */ 1217 &prio, /* 18 %ld */ 1218 &nice, /* 19 %ld */ 1219 &junk, /* 20 %ld */ 1220 &it_real, /* 21 %ld */ 1221 &start, /* 22 UINTX_FORMAT */ 1222 &vsize, /* 23 UINTX_FORMAT */ 1223 &rss, /* 24 INTX_FORMAT */ 1224 &rsslim, /* 25 UINTX_FORMAT */ 1225 &scodes, /* 26 UINTX_FORMAT */ 1226 &ecode, /* 27 UINTX_FORMAT */ 1227 &stack_start); /* 28 UINTX_FORMAT */ 1228 } 1229 1230 #undef _UFM 1231 #undef _DFM 1232 1233 if (i != 28 - 2) { 1234 assert(false, "Bad conversion from /proc/self/stat"); 1235 // product mode - assume we are the initial thread, good luck in the 1236 // embedded case. 1237 warning("Can't detect initial thread stack location - bad conversion"); 1238 stack_start = (uintptr_t) &rlim; 1239 } 1240 } else { 1241 // For some reason we can't open /proc/self/stat (for example, running on 1242 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1243 // most cases, so don't abort: 1244 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1245 stack_start = (uintptr_t) &rlim; 1246 } 1247 } 1248 1249 // Now we have a pointer (stack_start) very close to the stack top, the 1250 // next thing to do is to figure out the exact location of stack top. We 1251 // can find out the virtual memory area that contains stack_start by 1252 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1253 // and its upper limit is the real stack top. (again, this would fail if 1254 // running inside chroot, because /proc may not exist.) 1255 1256 uintptr_t stack_top; 1257 address low, high; 1258 if (find_vma((address)stack_start, &low, &high)) { 1259 // success, "high" is the true stack top. (ignore "low", because initial 1260 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1261 stack_top = (uintptr_t)high; 1262 } else { 1263 // failed, likely because /proc/self/maps does not exist 1264 warning("Can't detect initial thread stack location - find_vma failed"); 1265 // best effort: stack_start is normally within a few pages below the real 1266 // stack top, use it as stack top, and reduce stack size so we won't put 1267 // guard page outside stack. 1268 stack_top = stack_start; 1269 stack_size -= 16 * page_size(); 1270 } 1271 1272 // stack_top could be partially down the page so align it 1273 stack_top = align_size_up(stack_top, page_size()); 1274 1275 if (max_size && stack_size > max_size) { 1276 _initial_thread_stack_size = max_size; 1277 } else { 1278 _initial_thread_stack_size = stack_size; 1279 } 1280 1281 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1282 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1283 } 1284 1285 //////////////////////////////////////////////////////////////////////////////// 1286 // time support 1287 1288 // Time since start-up in seconds to a fine granularity. 1289 // Used by VMSelfDestructTimer and the MemProfiler. 1290 double os::elapsedTime() { 1291 1292 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1293 } 1294 1295 jlong os::elapsed_counter() { 1296 return javaTimeNanos() - initial_time_count; 1297 } 1298 1299 jlong os::elapsed_frequency() { 1300 return NANOSECS_PER_SEC; // nanosecond resolution 1301 } 1302 1303 bool os::supports_vtime() { return true; } 1304 bool os::enable_vtime() { return false; } 1305 bool os::vtime_enabled() { return false; } 1306 1307 double os::elapsedVTime() { 1308 struct rusage usage; 1309 int retval = getrusage(RUSAGE_THREAD, &usage); 1310 if (retval == 0) { 1311 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); 1312 } else { 1313 // better than nothing, but not much 1314 return elapsedTime(); 1315 } 1316 } 1317 1318 jlong os::javaTimeMillis() { 1319 timeval time; 1320 int status = gettimeofday(&time, NULL); 1321 assert(status != -1, "linux error"); 1322 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1323 } 1324 1325 #ifndef CLOCK_MONOTONIC 1326 #define CLOCK_MONOTONIC (1) 1327 #endif 1328 1329 void os::Linux::clock_init() { 1330 // we do dlopen's in this particular order due to bug in linux 1331 // dynamical loader (see 6348968) leading to crash on exit 1332 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1333 if (handle == NULL) { 1334 handle = dlopen("librt.so", RTLD_LAZY); 1335 } 1336 1337 if (handle) { 1338 int (*clock_getres_func)(clockid_t, struct timespec*) = 1339 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1340 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1341 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1342 if (clock_getres_func && clock_gettime_func) { 1343 // See if monotonic clock is supported by the kernel. Note that some 1344 // early implementations simply return kernel jiffies (updated every 1345 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1346 // for nano time (though the monotonic property is still nice to have). 1347 // It's fixed in newer kernels, however clock_getres() still returns 1348 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1349 // resolution for now. Hopefully as people move to new kernels, this 1350 // won't be a problem. 1351 struct timespec res; 1352 struct timespec tp; 1353 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1354 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1355 // yes, monotonic clock is supported 1356 _clock_gettime = clock_gettime_func; 1357 return; 1358 } else { 1359 // close librt if there is no monotonic clock 1360 dlclose(handle); 1361 } 1362 } 1363 } 1364 warning("No monotonic clock was available - timed services may " \ 1365 "be adversely affected if the time-of-day clock changes"); 1366 } 1367 1368 #ifndef SYS_clock_getres 1369 1370 #if defined(IA32) || defined(AMD64) 1371 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1372 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1373 #else 1374 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1375 #define sys_clock_getres(x,y) -1 1376 #endif 1377 1378 #else 1379 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1380 #endif 1381 1382 void os::Linux::fast_thread_clock_init() { 1383 if (!UseLinuxPosixThreadCPUClocks) { 1384 return; 1385 } 1386 clockid_t clockid; 1387 struct timespec tp; 1388 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1389 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1390 1391 // Switch to using fast clocks for thread cpu time if 1392 // the sys_clock_getres() returns 0 error code. 1393 // Note, that some kernels may support the current thread 1394 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1395 // returned by the pthread_getcpuclockid(). 1396 // If the fast Posix clocks are supported then the sys_clock_getres() 1397 // must return at least tp.tv_sec == 0 which means a resolution 1398 // better than 1 sec. This is extra check for reliability. 1399 1400 if(pthread_getcpuclockid_func && 1401 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1402 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1403 1404 _supports_fast_thread_cpu_time = true; 1405 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1406 } 1407 } 1408 1409 jlong os::javaTimeNanos() { 1410 if (Linux::supports_monotonic_clock()) { 1411 struct timespec tp; 1412 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1413 assert(status == 0, "gettime error"); 1414 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1415 return result; 1416 } else { 1417 timeval time; 1418 int status = gettimeofday(&time, NULL); 1419 assert(status != -1, "linux error"); 1420 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1421 return 1000 * usecs; 1422 } 1423 } 1424 1425 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1426 if (Linux::supports_monotonic_clock()) { 1427 info_ptr->max_value = ALL_64_BITS; 1428 1429 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1430 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1431 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1432 } else { 1433 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1434 info_ptr->max_value = ALL_64_BITS; 1435 1436 // gettimeofday is a real time clock so it skips 1437 info_ptr->may_skip_backward = true; 1438 info_ptr->may_skip_forward = true; 1439 } 1440 1441 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1442 } 1443 1444 // Return the real, user, and system times in seconds from an 1445 // arbitrary fixed point in the past. 1446 bool os::getTimesSecs(double* process_real_time, 1447 double* process_user_time, 1448 double* process_system_time) { 1449 struct tms ticks; 1450 clock_t real_ticks = times(&ticks); 1451 1452 if (real_ticks == (clock_t) (-1)) { 1453 return false; 1454 } else { 1455 double ticks_per_second = (double) clock_tics_per_sec; 1456 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1457 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1458 *process_real_time = ((double) real_ticks) / ticks_per_second; 1459 1460 return true; 1461 } 1462 } 1463 1464 1465 char * os::local_time_string(char *buf, size_t buflen) { 1466 struct tm t; 1467 time_t long_time; 1468 time(&long_time); 1469 localtime_r(&long_time, &t); 1470 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1471 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1472 t.tm_hour, t.tm_min, t.tm_sec); 1473 return buf; 1474 } 1475 1476 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1477 return localtime_r(clock, res); 1478 } 1479 1480 //////////////////////////////////////////////////////////////////////////////// 1481 // runtime exit support 1482 1483 // Note: os::shutdown() might be called very early during initialization, or 1484 // called from signal handler. Before adding something to os::shutdown(), make 1485 // sure it is async-safe and can handle partially initialized VM. 1486 void os::shutdown() { 1487 1488 // allow PerfMemory to attempt cleanup of any persistent resources 1489 perfMemory_exit(); 1490 1491 // needs to remove object in file system 1492 AttachListener::abort(); 1493 1494 // flush buffered output, finish log files 1495 ostream_abort(); 1496 1497 // Check for abort hook 1498 abort_hook_t abort_hook = Arguments::abort_hook(); 1499 if (abort_hook != NULL) { 1500 abort_hook(); 1501 } 1502 1503 } 1504 1505 // Note: os::abort() might be called very early during initialization, or 1506 // called from signal handler. Before adding something to os::abort(), make 1507 // sure it is async-safe and can handle partially initialized VM. 1508 void os::abort(bool dump_core) { 1509 os::shutdown(); 1510 if (dump_core) { 1511 #ifndef PRODUCT 1512 fdStream out(defaultStream::output_fd()); 1513 out.print_raw("Current thread is "); 1514 char buf[16]; 1515 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1516 out.print_raw_cr(buf); 1517 out.print_raw_cr("Dumping core ..."); 1518 #endif 1519 ::abort(); // dump core 1520 } 1521 1522 ::exit(1); 1523 } 1524 1525 // Die immediately, no exit hook, no abort hook, no cleanup. 1526 void os::die() { 1527 // _exit() on LinuxThreads only kills current thread 1528 ::abort(); 1529 } 1530 1531 1532 // This method is a copy of JDK's sysGetLastErrorString 1533 // from src/solaris/hpi/src/system_md.c 1534 1535 size_t os::lasterror(char *buf, size_t len) { 1536 1537 if (errno == 0) return 0; 1538 1539 const char *s = ::strerror(errno); 1540 size_t n = ::strlen(s); 1541 if (n >= len) { 1542 n = len - 1; 1543 } 1544 ::strncpy(buf, s, n); 1545 buf[n] = '\0'; 1546 return n; 1547 } 1548 1549 intx os::current_thread_id() { return (intx)pthread_self(); } 1550 int os::current_process_id() { 1551 1552 // Under the old linux thread library, linux gives each thread 1553 // its own process id. Because of this each thread will return 1554 // a different pid if this method were to return the result 1555 // of getpid(2). Linux provides no api that returns the pid 1556 // of the launcher thread for the vm. This implementation 1557 // returns a unique pid, the pid of the launcher thread 1558 // that starts the vm 'process'. 1559 1560 // Under the NPTL, getpid() returns the same pid as the 1561 // launcher thread rather than a unique pid per thread. 1562 // Use gettid() if you want the old pre NPTL behaviour. 1563 1564 // if you are looking for the result of a call to getpid() that 1565 // returns a unique pid for the calling thread, then look at the 1566 // OSThread::thread_id() method in osThread_linux.hpp file 1567 1568 return (int)(_initial_pid ? _initial_pid : getpid()); 1569 } 1570 1571 // DLL functions 1572 1573 const char* os::dll_file_extension() { return ".so"; } 1574 1575 // This must be hard coded because it's the system's temporary 1576 // directory not the java application's temp directory, ala java.io.tmpdir. 1577 const char* os::get_temp_directory() { return "/tmp"; } 1578 1579 static bool file_exists(const char* filename) { 1580 struct stat statbuf; 1581 if (filename == NULL || strlen(filename) == 0) { 1582 return false; 1583 } 1584 return os::stat(filename, &statbuf) == 0; 1585 } 1586 1587 bool os::dll_build_name(char* buffer, size_t buflen, 1588 const char* pname, const char* fname) { 1589 bool retval = false; 1590 // Copied from libhpi 1591 const size_t pnamelen = pname ? strlen(pname) : 0; 1592 1593 // Return error on buffer overflow. 1594 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1595 return retval; 1596 } 1597 1598 if (pnamelen == 0) { 1599 snprintf(buffer, buflen, "lib%s.so", fname); 1600 retval = true; 1601 } else if (strchr(pname, *os::path_separator()) != NULL) { 1602 int n; 1603 char** pelements = split_path(pname, &n); 1604 if (pelements == NULL) { 1605 return false; 1606 } 1607 for (int i = 0 ; i < n ; i++) { 1608 // Really shouldn't be NULL, but check can't hurt 1609 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1610 continue; // skip the empty path values 1611 } 1612 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1613 if (file_exists(buffer)) { 1614 retval = true; 1615 break; 1616 } 1617 } 1618 // release the storage 1619 for (int i = 0 ; i < n ; i++) { 1620 if (pelements[i] != NULL) { 1621 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal); 1622 } 1623 } 1624 if (pelements != NULL) { 1625 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal); 1626 } 1627 } else { 1628 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1629 retval = true; 1630 } 1631 return retval; 1632 } 1633 1634 // check if addr is inside libjvm.so 1635 bool os::address_is_in_vm(address addr) { 1636 static address libjvm_base_addr; 1637 Dl_info dlinfo; 1638 1639 if (libjvm_base_addr == NULL) { 1640 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1641 libjvm_base_addr = (address)dlinfo.dli_fbase; 1642 } 1643 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1644 } 1645 1646 if (dladdr((void *)addr, &dlinfo) != 0) { 1647 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1648 } 1649 1650 return false; 1651 } 1652 1653 bool os::dll_address_to_function_name(address addr, char *buf, 1654 int buflen, int *offset) { 1655 // buf is not optional, but offset is optional 1656 assert(buf != NULL, "sanity check"); 1657 1658 Dl_info dlinfo; 1659 1660 if (dladdr((void*)addr, &dlinfo) != 0) { 1661 // see if we have a matching symbol 1662 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1663 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1664 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1665 } 1666 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1667 return true; 1668 } 1669 // no matching symbol so try for just file info 1670 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1671 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1672 buf, buflen, offset, dlinfo.dli_fname)) { 1673 return true; 1674 } 1675 } 1676 } 1677 1678 buf[0] = '\0'; 1679 if (offset != NULL) *offset = -1; 1680 return false; 1681 } 1682 1683 struct _address_to_library_name { 1684 address addr; // input : memory address 1685 size_t buflen; // size of fname 1686 char* fname; // output: library name 1687 address base; // library base addr 1688 }; 1689 1690 static int address_to_library_name_callback(struct dl_phdr_info *info, 1691 size_t size, void *data) { 1692 int i; 1693 bool found = false; 1694 address libbase = NULL; 1695 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1696 1697 // iterate through all loadable segments 1698 for (i = 0; i < info->dlpi_phnum; i++) { 1699 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1700 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1701 // base address of a library is the lowest address of its loaded 1702 // segments. 1703 if (libbase == NULL || libbase > segbase) { 1704 libbase = segbase; 1705 } 1706 // see if 'addr' is within current segment 1707 if (segbase <= d->addr && 1708 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1709 found = true; 1710 } 1711 } 1712 } 1713 1714 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1715 // so dll_address_to_library_name() can fall through to use dladdr() which 1716 // can figure out executable name from argv[0]. 1717 if (found && info->dlpi_name && info->dlpi_name[0]) { 1718 d->base = libbase; 1719 if (d->fname) { 1720 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1721 } 1722 return 1; 1723 } 1724 return 0; 1725 } 1726 1727 bool os::dll_address_to_library_name(address addr, char* buf, 1728 int buflen, int* offset) { 1729 // buf is not optional, but offset is optional 1730 assert(buf != NULL, "sanity check"); 1731 1732 Dl_info dlinfo; 1733 struct _address_to_library_name data; 1734 1735 // There is a bug in old glibc dladdr() implementation that it could resolve 1736 // to wrong library name if the .so file has a base address != NULL. Here 1737 // we iterate through the program headers of all loaded libraries to find 1738 // out which library 'addr' really belongs to. This workaround can be 1739 // removed once the minimum requirement for glibc is moved to 2.3.x. 1740 data.addr = addr; 1741 data.fname = buf; 1742 data.buflen = buflen; 1743 data.base = NULL; 1744 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1745 1746 if (rslt) { 1747 // buf already contains library name 1748 if (offset) *offset = addr - data.base; 1749 return true; 1750 } 1751 if (dladdr((void*)addr, &dlinfo) != 0) { 1752 if (dlinfo.dli_fname != NULL) { 1753 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1754 } 1755 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1756 *offset = addr - (address)dlinfo.dli_fbase; 1757 } 1758 return true; 1759 } 1760 1761 buf[0] = '\0'; 1762 if (offset) *offset = -1; 1763 return false; 1764 } 1765 1766 // Loads .dll/.so and 1767 // in case of error it checks if .dll/.so was built for the 1768 // same architecture as Hotspot is running on 1769 1770 1771 // Remember the stack's state. The Linux dynamic linker will change 1772 // the stack to 'executable' at most once, so we must safepoint only once. 1773 bool os::Linux::_stack_is_executable = false; 1774 1775 // VM operation that loads a library. This is necessary if stack protection 1776 // of the Java stacks can be lost during loading the library. If we 1777 // do not stop the Java threads, they can stack overflow before the stacks 1778 // are protected again. 1779 class VM_LinuxDllLoad: public VM_Operation { 1780 private: 1781 const char *_filename; 1782 char *_ebuf; 1783 int _ebuflen; 1784 void *_lib; 1785 public: 1786 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1787 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1788 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1789 void doit() { 1790 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1791 os::Linux::_stack_is_executable = true; 1792 } 1793 void* loaded_library() { return _lib; } 1794 }; 1795 1796 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1797 { 1798 void * result = NULL; 1799 bool load_attempted = false; 1800 1801 // Check whether the library to load might change execution rights 1802 // of the stack. If they are changed, the protection of the stack 1803 // guard pages will be lost. We need a safepoint to fix this. 1804 // 1805 // See Linux man page execstack(8) for more info. 1806 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1807 ElfFile ef(filename); 1808 if (!ef.specifies_noexecstack()) { 1809 if (!is_init_completed()) { 1810 os::Linux::_stack_is_executable = true; 1811 // This is OK - No Java threads have been created yet, and hence no 1812 // stack guard pages to fix. 1813 // 1814 // This should happen only when you are building JDK7 using a very 1815 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1816 // 1817 // Dynamic loader will make all stacks executable after 1818 // this function returns, and will not do that again. 1819 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1820 } else { 1821 warning("You have loaded library %s which might have disabled stack guard. " 1822 "The VM will try to fix the stack guard now.\n" 1823 "It's highly recommended that you fix the library with " 1824 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1825 filename); 1826 1827 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1828 JavaThread *jt = JavaThread::current(); 1829 if (jt->thread_state() != _thread_in_native) { 1830 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1831 // that requires ExecStack. Cannot enter safe point. Let's give up. 1832 warning("Unable to fix stack guard. Giving up."); 1833 } else { 1834 if (!LoadExecStackDllInVMThread) { 1835 // This is for the case where the DLL has an static 1836 // constructor function that executes JNI code. We cannot 1837 // load such DLLs in the VMThread. 1838 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1839 } 1840 1841 ThreadInVMfromNative tiv(jt); 1842 debug_only(VMNativeEntryWrapper vew;) 1843 1844 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1845 VMThread::execute(&op); 1846 if (LoadExecStackDllInVMThread) { 1847 result = op.loaded_library(); 1848 } 1849 load_attempted = true; 1850 } 1851 } 1852 } 1853 } 1854 1855 if (!load_attempted) { 1856 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1857 } 1858 1859 if (result != NULL) { 1860 // Successful loading 1861 return result; 1862 } 1863 1864 Elf32_Ehdr elf_head; 1865 int diag_msg_max_length=ebuflen-strlen(ebuf); 1866 char* diag_msg_buf=ebuf+strlen(ebuf); 1867 1868 if (diag_msg_max_length==0) { 1869 // No more space in ebuf for additional diagnostics message 1870 return NULL; 1871 } 1872 1873 1874 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1875 1876 if (file_descriptor < 0) { 1877 // Can't open library, report dlerror() message 1878 return NULL; 1879 } 1880 1881 bool failed_to_read_elf_head= 1882 (sizeof(elf_head)!= 1883 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1884 1885 ::close(file_descriptor); 1886 if (failed_to_read_elf_head) { 1887 // file i/o error - report dlerror() msg 1888 return NULL; 1889 } 1890 1891 typedef struct { 1892 Elf32_Half code; // Actual value as defined in elf.h 1893 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1894 char elf_class; // 32 or 64 bit 1895 char endianess; // MSB or LSB 1896 char* name; // String representation 1897 } arch_t; 1898 1899 #ifndef EM_486 1900 #define EM_486 6 /* Intel 80486 */ 1901 #endif 1902 1903 static const arch_t arch_array[]={ 1904 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1905 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1906 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1907 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1908 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1909 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1910 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1911 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1912 #if defined(VM_LITTLE_ENDIAN) 1913 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1914 #else 1915 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1916 #endif 1917 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1918 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1919 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1920 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1921 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1922 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1923 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1924 }; 1925 1926 #if (defined IA32) 1927 static Elf32_Half running_arch_code=EM_386; 1928 #elif (defined AMD64) 1929 static Elf32_Half running_arch_code=EM_X86_64; 1930 #elif (defined IA64) 1931 static Elf32_Half running_arch_code=EM_IA_64; 1932 #elif (defined __sparc) && (defined _LP64) 1933 static Elf32_Half running_arch_code=EM_SPARCV9; 1934 #elif (defined __sparc) && (!defined _LP64) 1935 static Elf32_Half running_arch_code=EM_SPARC; 1936 #elif (defined __powerpc64__) 1937 static Elf32_Half running_arch_code=EM_PPC64; 1938 #elif (defined __powerpc__) 1939 static Elf32_Half running_arch_code=EM_PPC; 1940 #elif (defined ARM) 1941 static Elf32_Half running_arch_code=EM_ARM; 1942 #elif (defined S390) 1943 static Elf32_Half running_arch_code=EM_S390; 1944 #elif (defined ALPHA) 1945 static Elf32_Half running_arch_code=EM_ALPHA; 1946 #elif (defined MIPSEL) 1947 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1948 #elif (defined PARISC) 1949 static Elf32_Half running_arch_code=EM_PARISC; 1950 #elif (defined MIPS) 1951 static Elf32_Half running_arch_code=EM_MIPS; 1952 #elif (defined M68K) 1953 static Elf32_Half running_arch_code=EM_68K; 1954 #else 1955 #error Method os::dll_load requires that one of following is defined:\ 1956 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1957 #endif 1958 1959 // Identify compatability class for VM's architecture and library's architecture 1960 // Obtain string descriptions for architectures 1961 1962 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1963 int running_arch_index=-1; 1964 1965 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1966 if (running_arch_code == arch_array[i].code) { 1967 running_arch_index = i; 1968 } 1969 if (lib_arch.code == arch_array[i].code) { 1970 lib_arch.compat_class = arch_array[i].compat_class; 1971 lib_arch.name = arch_array[i].name; 1972 } 1973 } 1974 1975 assert(running_arch_index != -1, 1976 "Didn't find running architecture code (running_arch_code) in arch_array"); 1977 if (running_arch_index == -1) { 1978 // Even though running architecture detection failed 1979 // we may still continue with reporting dlerror() message 1980 return NULL; 1981 } 1982 1983 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1984 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1985 return NULL; 1986 } 1987 1988 #ifndef S390 1989 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1990 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1991 return NULL; 1992 } 1993 #endif // !S390 1994 1995 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1996 if ( lib_arch.name!=NULL ) { 1997 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1998 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1999 lib_arch.name, arch_array[running_arch_index].name); 2000 } else { 2001 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 2002 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 2003 lib_arch.code, 2004 arch_array[running_arch_index].name); 2005 } 2006 } 2007 2008 return NULL; 2009 } 2010 2011 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) { 2012 void * result = ::dlopen(filename, RTLD_LAZY); 2013 if (result == NULL) { 2014 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 2015 ebuf[ebuflen-1] = '\0'; 2016 } 2017 return result; 2018 } 2019 2020 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) { 2021 void * result = NULL; 2022 if (LoadExecStackDllInVMThread) { 2023 result = dlopen_helper(filename, ebuf, ebuflen); 2024 } 2025 2026 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 2027 // library that requires an executable stack, or which does not have this 2028 // stack attribute set, dlopen changes the stack attribute to executable. The 2029 // read protection of the guard pages gets lost. 2030 // 2031 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 2032 // may have been queued at the same time. 2033 2034 if (!_stack_is_executable) { 2035 JavaThread *jt = Threads::first(); 2036 2037 while (jt) { 2038 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 2039 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 2040 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 2041 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 2042 warning("Attempt to reguard stack yellow zone failed."); 2043 } 2044 } 2045 jt = jt->next(); 2046 } 2047 } 2048 2049 return result; 2050 } 2051 2052 /* 2053 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 2054 * chances are you might want to run the generated bits against glibc-2.0 2055 * libdl.so, so always use locking for any version of glibc. 2056 */ 2057 void* os::dll_lookup(void* handle, const char* name) { 2058 pthread_mutex_lock(&dl_mutex); 2059 void* res = dlsym(handle, name); 2060 pthread_mutex_unlock(&dl_mutex); 2061 return res; 2062 } 2063 2064 void* os::get_default_process_handle() { 2065 return (void*)::dlopen(NULL, RTLD_LAZY); 2066 } 2067 2068 static bool _print_ascii_file(const char* filename, outputStream* st) { 2069 int fd = ::open(filename, O_RDONLY); 2070 if (fd == -1) { 2071 return false; 2072 } 2073 2074 char buf[32]; 2075 int bytes; 2076 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2077 st->print_raw(buf, bytes); 2078 } 2079 2080 ::close(fd); 2081 2082 return true; 2083 } 2084 2085 void os::print_dll_info(outputStream *st) { 2086 st->print_cr("Dynamic libraries:"); 2087 2088 char fname[32]; 2089 pid_t pid = os::Linux::gettid(); 2090 2091 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2092 2093 if (!_print_ascii_file(fname, st)) { 2094 st->print("Can not get library information for pid = %d\n", pid); 2095 } 2096 } 2097 2098 void os::print_os_info_brief(outputStream* st) { 2099 os::Linux::print_distro_info(st); 2100 2101 os::Posix::print_uname_info(st); 2102 2103 os::Linux::print_libversion_info(st); 2104 2105 } 2106 2107 void os::print_os_info(outputStream* st) { 2108 st->print("OS:"); 2109 2110 os::Linux::print_distro_info(st); 2111 2112 os::Posix::print_uname_info(st); 2113 2114 // Print warning if unsafe chroot environment detected 2115 if (unsafe_chroot_detected) { 2116 st->print("WARNING!! "); 2117 st->print_cr("%s", unstable_chroot_error); 2118 } 2119 2120 os::Linux::print_libversion_info(st); 2121 2122 os::Posix::print_rlimit_info(st); 2123 2124 os::Posix::print_load_average(st); 2125 2126 os::Linux::print_full_memory_info(st); 2127 } 2128 2129 // Try to identify popular distros. 2130 // Most Linux distributions have a /etc/XXX-release file, which contains 2131 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2132 // file that also contains the OS version string. Some have more than one 2133 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2134 // /etc/redhat-release.), so the order is important. 2135 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2136 // their own specific XXX-release file as well as a redhat-release file. 2137 // Because of this the XXX-release file needs to be searched for before the 2138 // redhat-release file. 2139 // Since Red Hat has a lsb-release file that is not very descriptive the 2140 // search for redhat-release needs to be before lsb-release. 2141 // Since the lsb-release file is the new standard it needs to be searched 2142 // before the older style release files. 2143 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2144 // next to last resort. The os-release file is a new standard that contains 2145 // distribution information and the system-release file seems to be an old 2146 // standard that has been replaced by the lsb-release and os-release files. 2147 // Searching for the debian_version file is the last resort. It contains 2148 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2149 // "Debian " is printed before the contents of the debian_version file. 2150 void os::Linux::print_distro_info(outputStream* st) { 2151 if (!_print_ascii_file("/etc/oracle-release", st) && 2152 !_print_ascii_file("/etc/mandriva-release", st) && 2153 !_print_ascii_file("/etc/mandrake-release", st) && 2154 !_print_ascii_file("/etc/sun-release", st) && 2155 !_print_ascii_file("/etc/redhat-release", st) && 2156 !_print_ascii_file("/etc/lsb-release", st) && 2157 !_print_ascii_file("/etc/SuSE-release", st) && 2158 !_print_ascii_file("/etc/turbolinux-release", st) && 2159 !_print_ascii_file("/etc/gentoo-release", st) && 2160 !_print_ascii_file("/etc/ltib-release", st) && 2161 !_print_ascii_file("/etc/angstrom-version", st) && 2162 !_print_ascii_file("/etc/system-release", st) && 2163 !_print_ascii_file("/etc/os-release", st)) { 2164 2165 if (file_exists("/etc/debian_version")) { 2166 st->print("Debian "); 2167 _print_ascii_file("/etc/debian_version", st); 2168 } else { 2169 st->print("Linux"); 2170 } 2171 } 2172 st->cr(); 2173 } 2174 2175 void os::Linux::print_libversion_info(outputStream* st) { 2176 // libc, pthread 2177 st->print("libc:"); 2178 st->print("%s ", os::Linux::glibc_version()); 2179 st->print("%s ", os::Linux::libpthread_version()); 2180 if (os::Linux::is_LinuxThreads()) { 2181 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2182 } 2183 st->cr(); 2184 } 2185 2186 void os::Linux::print_full_memory_info(outputStream* st) { 2187 st->print("\n/proc/meminfo:\n"); 2188 _print_ascii_file("/proc/meminfo", st); 2189 st->cr(); 2190 } 2191 2192 void os::print_memory_info(outputStream* st) { 2193 2194 st->print("Memory:"); 2195 st->print(" %dk page", os::vm_page_size()>>10); 2196 2197 // values in struct sysinfo are "unsigned long" 2198 struct sysinfo si; 2199 sysinfo(&si); 2200 2201 st->print(", physical " UINT64_FORMAT "k", 2202 os::physical_memory() >> 10); 2203 st->print("(" UINT64_FORMAT "k free)", 2204 os::available_memory() >> 10); 2205 st->print(", swap " UINT64_FORMAT "k", 2206 ((jlong)si.totalswap * si.mem_unit) >> 10); 2207 st->print("(" UINT64_FORMAT "k free)", 2208 ((jlong)si.freeswap * si.mem_unit) >> 10); 2209 st->cr(); 2210 } 2211 2212 void os::pd_print_cpu_info(outputStream* st) { 2213 st->print("\n/proc/cpuinfo:\n"); 2214 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2215 st->print(" <Not Available>"); 2216 } 2217 st->cr(); 2218 } 2219 2220 void os::print_siginfo(outputStream* st, void* siginfo) { 2221 const siginfo_t* si = (const siginfo_t*)siginfo; 2222 2223 os::Posix::print_siginfo_brief(st, si); 2224 #if INCLUDE_CDS 2225 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2226 UseSharedSpaces) { 2227 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2228 if (mapinfo->is_in_shared_space(si->si_addr)) { 2229 st->print("\n\nError accessing class data sharing archive." \ 2230 " Mapped file inaccessible during execution, " \ 2231 " possible disk/network problem."); 2232 } 2233 } 2234 #endif 2235 st->cr(); 2236 } 2237 2238 2239 static void print_signal_handler(outputStream* st, int sig, 2240 char* buf, size_t buflen); 2241 2242 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2243 st->print_cr("Signal Handlers:"); 2244 print_signal_handler(st, SIGSEGV, buf, buflen); 2245 print_signal_handler(st, SIGBUS , buf, buflen); 2246 print_signal_handler(st, SIGFPE , buf, buflen); 2247 print_signal_handler(st, SIGPIPE, buf, buflen); 2248 print_signal_handler(st, SIGXFSZ, buf, buflen); 2249 print_signal_handler(st, SIGILL , buf, buflen); 2250 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2251 print_signal_handler(st, SR_signum, buf, buflen); 2252 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2253 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2254 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2255 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2256 #if defined(PPC64) 2257 print_signal_handler(st, SIGTRAP, buf, buflen); 2258 #endif 2259 } 2260 2261 static char saved_jvm_path[MAXPATHLEN] = {0}; 2262 2263 // Find the full path to the current module, libjvm.so 2264 void os::jvm_path(char *buf, jint buflen) { 2265 // Error checking. 2266 if (buflen < MAXPATHLEN) { 2267 assert(false, "must use a large-enough buffer"); 2268 buf[0] = '\0'; 2269 return; 2270 } 2271 // Lazy resolve the path to current module. 2272 if (saved_jvm_path[0] != 0) { 2273 strcpy(buf, saved_jvm_path); 2274 return; 2275 } 2276 2277 char dli_fname[MAXPATHLEN]; 2278 bool ret = dll_address_to_library_name( 2279 CAST_FROM_FN_PTR(address, os::jvm_path), 2280 dli_fname, sizeof(dli_fname), NULL); 2281 assert(ret, "cannot locate libjvm"); 2282 char *rp = NULL; 2283 if (ret && dli_fname[0] != '\0') { 2284 rp = realpath(dli_fname, buf); 2285 } 2286 if (rp == NULL) 2287 return; 2288 2289 if (Arguments::created_by_gamma_launcher()) { 2290 // Support for the gamma launcher. Typical value for buf is 2291 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2292 // the right place in the string, then assume we are installed in a JDK and 2293 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2294 // up the path so it looks like libjvm.so is installed there (append a 2295 // fake suffix hotspot/libjvm.so). 2296 const char *p = buf + strlen(buf) - 1; 2297 for (int count = 0; p > buf && count < 5; ++count) { 2298 for (--p; p > buf && *p != '/'; --p) 2299 /* empty */ ; 2300 } 2301 2302 if (strncmp(p, "/jre/lib/", 9) != 0) { 2303 // Look for JAVA_HOME in the environment. 2304 char* java_home_var = ::getenv("JAVA_HOME"); 2305 if (java_home_var != NULL && java_home_var[0] != 0) { 2306 char* jrelib_p; 2307 int len; 2308 2309 // Check the current module name "libjvm.so". 2310 p = strrchr(buf, '/'); 2311 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2312 2313 rp = realpath(java_home_var, buf); 2314 if (rp == NULL) 2315 return; 2316 2317 // determine if this is a legacy image or modules image 2318 // modules image doesn't have "jre" subdirectory 2319 len = strlen(buf); 2320 assert(len < buflen, "Ran out of buffer room"); 2321 jrelib_p = buf + len; 2322 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2323 if (0 != access(buf, F_OK)) { 2324 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2325 } 2326 2327 if (0 == access(buf, F_OK)) { 2328 // Use current module name "libjvm.so" 2329 len = strlen(buf); 2330 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2331 } else { 2332 // Go back to path of .so 2333 rp = realpath(dli_fname, buf); 2334 if (rp == NULL) 2335 return; 2336 } 2337 } 2338 } 2339 } 2340 2341 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2342 } 2343 2344 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2345 // no prefix required, not even "_" 2346 } 2347 2348 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2349 // no suffix required 2350 } 2351 2352 //////////////////////////////////////////////////////////////////////////////// 2353 // sun.misc.Signal support 2354 2355 static volatile jint sigint_count = 0; 2356 2357 static void 2358 UserHandler(int sig, void *siginfo, void *context) { 2359 // 4511530 - sem_post is serialized and handled by the manager thread. When 2360 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2361 // don't want to flood the manager thread with sem_post requests. 2362 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2363 return; 2364 2365 // Ctrl-C is pressed during error reporting, likely because the error 2366 // handler fails to abort. Let VM die immediately. 2367 if (sig == SIGINT && is_error_reported()) { 2368 os::die(); 2369 } 2370 2371 os::signal_notify(sig); 2372 } 2373 2374 void* os::user_handler() { 2375 return CAST_FROM_FN_PTR(void*, UserHandler); 2376 } 2377 2378 class Semaphore : public StackObj { 2379 public: 2380 Semaphore(); 2381 ~Semaphore(); 2382 void signal(); 2383 void wait(); 2384 bool trywait(); 2385 bool timedwait(unsigned int sec, int nsec); 2386 private: 2387 sem_t _semaphore; 2388 }; 2389 2390 Semaphore::Semaphore() { 2391 sem_init(&_semaphore, 0, 0); 2392 } 2393 2394 Semaphore::~Semaphore() { 2395 sem_destroy(&_semaphore); 2396 } 2397 2398 void Semaphore::signal() { 2399 sem_post(&_semaphore); 2400 } 2401 2402 void Semaphore::wait() { 2403 sem_wait(&_semaphore); 2404 } 2405 2406 bool Semaphore::trywait() { 2407 return sem_trywait(&_semaphore) == 0; 2408 } 2409 2410 bool Semaphore::timedwait(unsigned int sec, int nsec) { 2411 2412 struct timespec ts; 2413 // Semaphore's are always associated with CLOCK_REALTIME 2414 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2415 // see unpackTime for discussion on overflow checking 2416 if (sec >= MAX_SECS) { 2417 ts.tv_sec += MAX_SECS; 2418 ts.tv_nsec = 0; 2419 } else { 2420 ts.tv_sec += sec; 2421 ts.tv_nsec += nsec; 2422 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2423 ts.tv_nsec -= NANOSECS_PER_SEC; 2424 ++ts.tv_sec; // note: this must be <= max_secs 2425 } 2426 } 2427 2428 while (1) { 2429 int result = sem_timedwait(&_semaphore, &ts); 2430 if (result == 0) { 2431 return true; 2432 } else if (errno == EINTR) { 2433 continue; 2434 } else if (errno == ETIMEDOUT) { 2435 return false; 2436 } else { 2437 return false; 2438 } 2439 } 2440 } 2441 2442 extern "C" { 2443 typedef void (*sa_handler_t)(int); 2444 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2445 } 2446 2447 void* os::signal(int signal_number, void* handler) { 2448 struct sigaction sigAct, oldSigAct; 2449 2450 sigfillset(&(sigAct.sa_mask)); 2451 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2452 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2453 2454 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2455 // -1 means registration failed 2456 return (void *)-1; 2457 } 2458 2459 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2460 } 2461 2462 void os::signal_raise(int signal_number) { 2463 ::raise(signal_number); 2464 } 2465 2466 /* 2467 * The following code is moved from os.cpp for making this 2468 * code platform specific, which it is by its very nature. 2469 */ 2470 2471 // Will be modified when max signal is changed to be dynamic 2472 int os::sigexitnum_pd() { 2473 return NSIG; 2474 } 2475 2476 // a counter for each possible signal value 2477 static volatile jint pending_signals[NSIG+1] = { 0 }; 2478 2479 // Linux(POSIX) specific hand shaking semaphore. 2480 static sem_t sig_sem; 2481 static Semaphore sr_semaphore; 2482 2483 void os::signal_init_pd() { 2484 // Initialize signal structures 2485 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2486 2487 // Initialize signal semaphore 2488 ::sem_init(&sig_sem, 0, 0); 2489 } 2490 2491 void os::signal_notify(int sig) { 2492 Atomic::inc(&pending_signals[sig]); 2493 ::sem_post(&sig_sem); 2494 } 2495 2496 static int check_pending_signals(bool wait) { 2497 Atomic::store(0, &sigint_count); 2498 for (;;) { 2499 for (int i = 0; i < NSIG + 1; i++) { 2500 jint n = pending_signals[i]; 2501 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2502 return i; 2503 } 2504 } 2505 if (!wait) { 2506 return -1; 2507 } 2508 JavaThread *thread = JavaThread::current(); 2509 ThreadBlockInVM tbivm(thread); 2510 2511 bool threadIsSuspended; 2512 do { 2513 thread->set_suspend_equivalent(); 2514 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2515 ::sem_wait(&sig_sem); 2516 2517 // were we externally suspended while we were waiting? 2518 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2519 if (threadIsSuspended) { 2520 // 2521 // The semaphore has been incremented, but while we were waiting 2522 // another thread suspended us. We don't want to continue running 2523 // while suspended because that would surprise the thread that 2524 // suspended us. 2525 // 2526 ::sem_post(&sig_sem); 2527 2528 thread->java_suspend_self(); 2529 } 2530 } while (threadIsSuspended); 2531 } 2532 } 2533 2534 int os::signal_lookup() { 2535 return check_pending_signals(false); 2536 } 2537 2538 int os::signal_wait() { 2539 return check_pending_signals(true); 2540 } 2541 2542 //////////////////////////////////////////////////////////////////////////////// 2543 // Virtual Memory 2544 2545 int os::vm_page_size() { 2546 // Seems redundant as all get out 2547 assert(os::Linux::page_size() != -1, "must call os::init"); 2548 return os::Linux::page_size(); 2549 } 2550 2551 // Solaris allocates memory by pages. 2552 int os::vm_allocation_granularity() { 2553 assert(os::Linux::page_size() != -1, "must call os::init"); 2554 return os::Linux::page_size(); 2555 } 2556 2557 // Rationale behind this function: 2558 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2559 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2560 // samples for JITted code. Here we create private executable mapping over the code cache 2561 // and then we can use standard (well, almost, as mapping can change) way to provide 2562 // info for the reporting script by storing timestamp and location of symbol 2563 void linux_wrap_code(char* base, size_t size) { 2564 static volatile jint cnt = 0; 2565 2566 if (!UseOprofile) { 2567 return; 2568 } 2569 2570 char buf[PATH_MAX+1]; 2571 int num = Atomic::add(1, &cnt); 2572 2573 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2574 os::get_temp_directory(), os::current_process_id(), num); 2575 unlink(buf); 2576 2577 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2578 2579 if (fd != -1) { 2580 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2581 if (rv != (off_t)-1) { 2582 if (::write(fd, "", 1) == 1) { 2583 mmap(base, size, 2584 PROT_READ|PROT_WRITE|PROT_EXEC, 2585 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2586 } 2587 } 2588 ::close(fd); 2589 unlink(buf); 2590 } 2591 } 2592 2593 static bool recoverable_mmap_error(int err) { 2594 // See if the error is one we can let the caller handle. This 2595 // list of errno values comes from JBS-6843484. I can't find a 2596 // Linux man page that documents this specific set of errno 2597 // values so while this list currently matches Solaris, it may 2598 // change as we gain experience with this failure mode. 2599 switch (err) { 2600 case EBADF: 2601 case EINVAL: 2602 case ENOTSUP: 2603 // let the caller deal with these errors 2604 return true; 2605 2606 default: 2607 // Any remaining errors on this OS can cause our reserved mapping 2608 // to be lost. That can cause confusion where different data 2609 // structures think they have the same memory mapped. The worst 2610 // scenario is if both the VM and a library think they have the 2611 // same memory mapped. 2612 return false; 2613 } 2614 } 2615 2616 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2617 int err) { 2618 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2619 ", %d) failed; error='%s' (errno=%d)", addr, size, exec, 2620 strerror(err), err); 2621 } 2622 2623 static void warn_fail_commit_memory(char* addr, size_t size, 2624 size_t alignment_hint, bool exec, 2625 int err) { 2626 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2627 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size, 2628 alignment_hint, exec, strerror(err), err); 2629 } 2630 2631 // NOTE: Linux kernel does not really reserve the pages for us. 2632 // All it does is to check if there are enough free pages 2633 // left at the time of mmap(). This could be a potential 2634 // problem. 2635 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2636 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2637 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2638 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2639 if (res != (uintptr_t) MAP_FAILED) { 2640 if (UseNUMAInterleaving) { 2641 numa_make_global(addr, size); 2642 } 2643 return 0; 2644 } 2645 2646 int err = errno; // save errno from mmap() call above 2647 2648 if (!recoverable_mmap_error(err)) { 2649 warn_fail_commit_memory(addr, size, exec, err); 2650 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2651 } 2652 2653 return err; 2654 } 2655 2656 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2657 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2658 } 2659 2660 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2661 const char* mesg) { 2662 assert(mesg != NULL, "mesg must be specified"); 2663 int err = os::Linux::commit_memory_impl(addr, size, exec); 2664 if (err != 0) { 2665 // the caller wants all commit errors to exit with the specified mesg: 2666 warn_fail_commit_memory(addr, size, exec, err); 2667 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg); 2668 } 2669 } 2670 2671 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2672 #ifndef MAP_HUGETLB 2673 #define MAP_HUGETLB 0x40000 2674 #endif 2675 2676 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2677 #ifndef MADV_HUGEPAGE 2678 #define MADV_HUGEPAGE 14 2679 #endif 2680 2681 int os::Linux::commit_memory_impl(char* addr, size_t size, 2682 size_t alignment_hint, bool exec) { 2683 int err = os::Linux::commit_memory_impl(addr, size, exec); 2684 if (err == 0) { 2685 realign_memory(addr, size, alignment_hint); 2686 } 2687 return err; 2688 } 2689 2690 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2691 bool exec) { 2692 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2693 } 2694 2695 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2696 size_t alignment_hint, bool exec, 2697 const char* mesg) { 2698 assert(mesg != NULL, "mesg must be specified"); 2699 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2700 if (err != 0) { 2701 // the caller wants all commit errors to exit with the specified mesg: 2702 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2703 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg); 2704 } 2705 } 2706 2707 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2708 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2709 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2710 // be supported or the memory may already be backed by huge pages. 2711 ::madvise(addr, bytes, MADV_HUGEPAGE); 2712 } 2713 } 2714 2715 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2716 // This method works by doing an mmap over an existing mmaping and effectively discarding 2717 // the existing pages. However it won't work for SHM-based large pages that cannot be 2718 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2719 // small pages on top of the SHM segment. This method always works for small pages, so we 2720 // allow that in any case. 2721 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2722 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2723 } 2724 } 2725 2726 void os::numa_make_global(char *addr, size_t bytes) { 2727 Linux::numa_interleave_memory(addr, bytes); 2728 } 2729 2730 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2731 // bind policy to MPOL_PREFERRED for the current thread. 2732 #define USE_MPOL_PREFERRED 0 2733 2734 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2735 // To make NUMA and large pages more robust when both enabled, we need to ease 2736 // the requirements on where the memory should be allocated. MPOL_BIND is the 2737 // default policy and it will force memory to be allocated on the specified 2738 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2739 // the specified node, but will not force it. Using this policy will prevent 2740 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2741 // free large pages. 2742 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2743 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2744 } 2745 2746 bool os::numa_topology_changed() { return false; } 2747 2748 size_t os::numa_get_groups_num() { 2749 int max_node = Linux::numa_max_node(); 2750 return max_node > 0 ? max_node + 1 : 1; 2751 } 2752 2753 int os::numa_get_group_id() { 2754 int cpu_id = Linux::sched_getcpu(); 2755 if (cpu_id != -1) { 2756 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2757 if (lgrp_id != -1) { 2758 return lgrp_id; 2759 } 2760 } 2761 return 0; 2762 } 2763 2764 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2765 for (size_t i = 0; i < size; i++) { 2766 ids[i] = i; 2767 } 2768 return size; 2769 } 2770 2771 bool os::get_page_info(char *start, page_info* info) { 2772 return false; 2773 } 2774 2775 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2776 return end; 2777 } 2778 2779 2780 int os::Linux::sched_getcpu_syscall(void) { 2781 unsigned int cpu; 2782 int retval = -1; 2783 2784 #if defined(IA32) 2785 # ifndef SYS_getcpu 2786 # define SYS_getcpu 318 2787 # endif 2788 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2789 #elif defined(AMD64) 2790 // Unfortunately we have to bring all these macros here from vsyscall.h 2791 // to be able to compile on old linuxes. 2792 # define __NR_vgetcpu 2 2793 # define VSYSCALL_START (-10UL << 20) 2794 # define VSYSCALL_SIZE 1024 2795 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2796 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2797 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2798 retval = vgetcpu(&cpu, NULL, NULL); 2799 #endif 2800 2801 return (retval == -1) ? retval : cpu; 2802 } 2803 2804 // Something to do with the numa-aware allocator needs these symbols 2805 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2806 extern "C" JNIEXPORT void numa_error(char *where) { } 2807 extern "C" JNIEXPORT int fork1() { return fork(); } 2808 2809 2810 // If we are running with libnuma version > 2, then we should 2811 // be trying to use symbols with versions 1.1 2812 // If we are running with earlier version, which did not have symbol versions, 2813 // we should use the base version. 2814 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2815 void *f = dlvsym(handle, name, "libnuma_1.1"); 2816 if (f == NULL) { 2817 f = dlsym(handle, name); 2818 } 2819 return f; 2820 } 2821 2822 bool os::Linux::libnuma_init() { 2823 // sched_getcpu() should be in libc. 2824 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2825 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2826 2827 // If it's not, try a direct syscall. 2828 if (sched_getcpu() == -1) 2829 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall)); 2830 2831 if (sched_getcpu() != -1) { // Does it work? 2832 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2833 if (handle != NULL) { 2834 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2835 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2836 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2837 libnuma_dlsym(handle, "numa_max_node"))); 2838 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2839 libnuma_dlsym(handle, "numa_available"))); 2840 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2841 libnuma_dlsym(handle, "numa_tonode_memory"))); 2842 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2843 libnuma_dlsym(handle, "numa_interleave_memory"))); 2844 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2845 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2846 2847 2848 if (numa_available() != -1) { 2849 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2850 // Create a cpu -> node mapping 2851 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2852 rebuild_cpu_to_node_map(); 2853 return true; 2854 } 2855 } 2856 } 2857 return false; 2858 } 2859 2860 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2861 // The table is later used in get_node_by_cpu(). 2862 void os::Linux::rebuild_cpu_to_node_map() { 2863 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2864 // in libnuma (possible values are starting from 16, 2865 // and continuing up with every other power of 2, but less 2866 // than the maximum number of CPUs supported by kernel), and 2867 // is a subject to change (in libnuma version 2 the requirements 2868 // are more reasonable) we'll just hardcode the number they use 2869 // in the library. 2870 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2871 2872 size_t cpu_num = os::active_processor_count(); 2873 size_t cpu_map_size = NCPUS / BitsPerCLong; 2874 size_t cpu_map_valid_size = 2875 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2876 2877 cpu_to_node()->clear(); 2878 cpu_to_node()->at_grow(cpu_num - 1); 2879 size_t node_num = numa_get_groups_num(); 2880 2881 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2882 for (size_t i = 0; i < node_num; i++) { 2883 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2884 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2885 if (cpu_map[j] != 0) { 2886 for (size_t k = 0; k < BitsPerCLong; k++) { 2887 if (cpu_map[j] & (1UL << k)) { 2888 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2889 } 2890 } 2891 } 2892 } 2893 } 2894 } 2895 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal); 2896 } 2897 2898 int os::Linux::get_node_by_cpu(int cpu_id) { 2899 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2900 return cpu_to_node()->at(cpu_id); 2901 } 2902 return -1; 2903 } 2904 2905 GrowableArray<int>* os::Linux::_cpu_to_node; 2906 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2907 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2908 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2909 os::Linux::numa_available_func_t os::Linux::_numa_available; 2910 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2911 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2912 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2913 unsigned long* os::Linux::_numa_all_nodes; 2914 2915 bool os::pd_uncommit_memory(char* addr, size_t size) { 2916 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2917 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2918 return res != (uintptr_t) MAP_FAILED; 2919 } 2920 2921 static 2922 address get_stack_commited_bottom(address bottom, size_t size) { 2923 address nbot = bottom; 2924 address ntop = bottom + size; 2925 2926 size_t page_sz = os::vm_page_size(); 2927 unsigned pages = size / page_sz; 2928 2929 unsigned char vec[1]; 2930 unsigned imin = 1, imax = pages + 1, imid; 2931 int mincore_return_value = 0; 2932 2933 assert(imin <= imax, "Unexpected page size"); 2934 2935 while (imin < imax) { 2936 imid = (imax + imin) / 2; 2937 nbot = ntop - (imid * page_sz); 2938 2939 // Use a trick with mincore to check whether the page is mapped or not. 2940 // mincore sets vec to 1 if page resides in memory and to 0 if page 2941 // is swapped output but if page we are asking for is unmapped 2942 // it returns -1,ENOMEM 2943 mincore_return_value = mincore(nbot, page_sz, vec); 2944 2945 if (mincore_return_value == -1) { 2946 // Page is not mapped go up 2947 // to find first mapped page 2948 if (errno != EAGAIN) { 2949 assert(errno == ENOMEM, "Unexpected mincore errno"); 2950 imax = imid; 2951 } 2952 } else { 2953 // Page is mapped go down 2954 // to find first not mapped page 2955 imin = imid + 1; 2956 } 2957 } 2958 2959 nbot = nbot + page_sz; 2960 2961 // Adjust stack bottom one page up if last checked page is not mapped 2962 if (mincore_return_value == -1) { 2963 nbot = nbot + page_sz; 2964 } 2965 2966 return nbot; 2967 } 2968 2969 2970 // Linux uses a growable mapping for the stack, and if the mapping for 2971 // the stack guard pages is not removed when we detach a thread the 2972 // stack cannot grow beyond the pages where the stack guard was 2973 // mapped. If at some point later in the process the stack expands to 2974 // that point, the Linux kernel cannot expand the stack any further 2975 // because the guard pages are in the way, and a segfault occurs. 2976 // 2977 // However, it's essential not to split the stack region by unmapping 2978 // a region (leaving a hole) that's already part of the stack mapping, 2979 // so if the stack mapping has already grown beyond the guard pages at 2980 // the time we create them, we have to truncate the stack mapping. 2981 // So, we need to know the extent of the stack mapping when 2982 // create_stack_guard_pages() is called. 2983 2984 // We only need this for stacks that are growable: at the time of 2985 // writing thread stacks don't use growable mappings (i.e. those 2986 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2987 // only applies to the main thread. 2988 2989 // If the (growable) stack mapping already extends beyond the point 2990 // where we're going to put our guard pages, truncate the mapping at 2991 // that point by munmap()ping it. This ensures that when we later 2992 // munmap() the guard pages we don't leave a hole in the stack 2993 // mapping. This only affects the main/initial thread 2994 2995 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2996 2997 if (os::Linux::is_initial_thread()) { 2998 // As we manually grow stack up to bottom inside create_attached_thread(), 2999 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3000 // we don't need to do anything special. 3001 // Check it first, before calling heavy function. 3002 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3003 unsigned char vec[1]; 3004 3005 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3006 // Fallback to slow path on all errors, including EAGAIN 3007 stack_extent = (uintptr_t) get_stack_commited_bottom( 3008 os::Linux::initial_thread_stack_bottom(), 3009 (size_t)addr - stack_extent); 3010 } 3011 3012 if (stack_extent < (uintptr_t)addr) { 3013 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3014 } 3015 } 3016 3017 return os::commit_memory(addr, size, !ExecMem); 3018 } 3019 3020 // If this is a growable mapping, remove the guard pages entirely by 3021 // munmap()ping them. If not, just call uncommit_memory(). This only 3022 // affects the main/initial thread, but guard against future OS changes 3023 // It's safe to always unmap guard pages for initial thread because we 3024 // always place it right after end of the mapped region 3025 3026 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3027 uintptr_t stack_extent, stack_base; 3028 3029 if (os::Linux::is_initial_thread()) { 3030 return ::munmap(addr, size) == 0; 3031 } 3032 3033 return os::uncommit_memory(addr, size); 3034 } 3035 3036 static address _highest_vm_reserved_address = NULL; 3037 3038 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3039 // at 'requested_addr'. If there are existing memory mappings at the same 3040 // location, however, they will be overwritten. If 'fixed' is false, 3041 // 'requested_addr' is only treated as a hint, the return value may or 3042 // may not start from the requested address. Unlike Linux mmap(), this 3043 // function returns NULL to indicate failure. 3044 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3045 char * addr; 3046 int flags; 3047 3048 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3049 if (fixed) { 3050 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3051 flags |= MAP_FIXED; 3052 } 3053 3054 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3055 // touch an uncommitted page. Otherwise, the read/write might 3056 // succeed if we have enough swap space to back the physical page. 3057 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3058 flags, -1, 0); 3059 3060 if (addr != MAP_FAILED) { 3061 // anon_mmap() should only get called during VM initialization, 3062 // don't need lock (actually we can skip locking even it can be called 3063 // from multiple threads, because _highest_vm_reserved_address is just a 3064 // hint about the upper limit of non-stack memory regions.) 3065 if ((address)addr + bytes > _highest_vm_reserved_address) { 3066 _highest_vm_reserved_address = (address)addr + bytes; 3067 } 3068 } 3069 3070 return addr == MAP_FAILED ? NULL : addr; 3071 } 3072 3073 // Don't update _highest_vm_reserved_address, because there might be memory 3074 // regions above addr + size. If so, releasing a memory region only creates 3075 // a hole in the address space, it doesn't help prevent heap-stack collision. 3076 // 3077 static int anon_munmap(char * addr, size_t size) { 3078 return ::munmap(addr, size) == 0; 3079 } 3080 3081 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3082 size_t alignment_hint) { 3083 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3084 } 3085 3086 bool os::pd_release_memory(char* addr, size_t size) { 3087 return anon_munmap(addr, size); 3088 } 3089 3090 static address highest_vm_reserved_address() { 3091 return _highest_vm_reserved_address; 3092 } 3093 3094 static bool linux_mprotect(char* addr, size_t size, int prot) { 3095 // Linux wants the mprotect address argument to be page aligned. 3096 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3097 3098 // According to SUSv3, mprotect() should only be used with mappings 3099 // established by mmap(), and mmap() always maps whole pages. Unaligned 3100 // 'addr' likely indicates problem in the VM (e.g. trying to change 3101 // protection of malloc'ed or statically allocated memory). Check the 3102 // caller if you hit this assert. 3103 assert(addr == bottom, "sanity check"); 3104 3105 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3106 return ::mprotect(bottom, size, prot) == 0; 3107 } 3108 3109 // Set protections specified 3110 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3111 bool is_committed) { 3112 unsigned int p = 0; 3113 switch (prot) { 3114 case MEM_PROT_NONE: p = PROT_NONE; break; 3115 case MEM_PROT_READ: p = PROT_READ; break; 3116 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3117 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3118 default: 3119 ShouldNotReachHere(); 3120 } 3121 // is_committed is unused. 3122 return linux_mprotect(addr, bytes, p); 3123 } 3124 3125 bool os::guard_memory(char* addr, size_t size) { 3126 return linux_mprotect(addr, size, PROT_NONE); 3127 } 3128 3129 bool os::unguard_memory(char* addr, size_t size) { 3130 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3131 } 3132 3133 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) { 3134 bool result = false; 3135 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3136 MAP_ANONYMOUS|MAP_PRIVATE, 3137 -1, 0); 3138 if (p != MAP_FAILED) { 3139 void *aligned_p = align_ptr_up(p, page_size); 3140 3141 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3142 3143 munmap(p, page_size * 2); 3144 } 3145 3146 if (warn && !result) { 3147 warning("TransparentHugePages is not supported by the operating system."); 3148 } 3149 3150 return result; 3151 } 3152 3153 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3154 bool result = false; 3155 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3156 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3157 -1, 0); 3158 3159 if (p != MAP_FAILED) { 3160 // We don't know if this really is a huge page or not. 3161 FILE *fp = fopen("/proc/self/maps", "r"); 3162 if (fp) { 3163 while (!feof(fp)) { 3164 char chars[257]; 3165 long x = 0; 3166 if (fgets(chars, sizeof(chars), fp)) { 3167 if (sscanf(chars, "%lx-%*x", &x) == 1 3168 && x == (long)p) { 3169 if (strstr (chars, "hugepage")) { 3170 result = true; 3171 break; 3172 } 3173 } 3174 } 3175 } 3176 fclose(fp); 3177 } 3178 munmap(p, page_size); 3179 } 3180 3181 if (warn && !result) { 3182 warning("HugeTLBFS is not supported by the operating system."); 3183 } 3184 3185 return result; 3186 } 3187 3188 /* 3189 * Set the coredump_filter bits to include largepages in core dump (bit 6) 3190 * 3191 * From the coredump_filter documentation: 3192 * 3193 * - (bit 0) anonymous private memory 3194 * - (bit 1) anonymous shared memory 3195 * - (bit 2) file-backed private memory 3196 * - (bit 3) file-backed shared memory 3197 * - (bit 4) ELF header pages in file-backed private memory areas (it is 3198 * effective only if the bit 2 is cleared) 3199 * - (bit 5) hugetlb private memory 3200 * - (bit 6) hugetlb shared memory 3201 */ 3202 static void set_coredump_filter(void) { 3203 FILE *f; 3204 long cdm; 3205 3206 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3207 return; 3208 } 3209 3210 if (fscanf(f, "%lx", &cdm) != 1) { 3211 fclose(f); 3212 return; 3213 } 3214 3215 rewind(f); 3216 3217 if ((cdm & LARGEPAGES_BIT) == 0) { 3218 cdm |= LARGEPAGES_BIT; 3219 fprintf(f, "%#lx", cdm); 3220 } 3221 3222 fclose(f); 3223 } 3224 3225 // Large page support 3226 3227 static size_t _large_page_size = 0; 3228 3229 size_t os::Linux::find_large_page_size() { 3230 size_t large_page_size = 0; 3231 3232 // large_page_size on Linux is used to round up heap size. x86 uses either 3233 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3234 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3235 // page as large as 256M. 3236 // 3237 // Here we try to figure out page size by parsing /proc/meminfo and looking 3238 // for a line with the following format: 3239 // Hugepagesize: 2048 kB 3240 // 3241 // If we can't determine the value (e.g. /proc is not mounted, or the text 3242 // format has been changed), we'll use the largest page size supported by 3243 // the processor. 3244 3245 #ifndef ZERO 3246 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3247 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3248 #endif // ZERO 3249 3250 FILE *fp = fopen("/proc/meminfo", "r"); 3251 if (fp) { 3252 while (!feof(fp)) { 3253 int x = 0; 3254 char buf[16]; 3255 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3256 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3257 large_page_size = x * K; 3258 break; 3259 } 3260 } else { 3261 // skip to next line 3262 for (;;) { 3263 int ch = fgetc(fp); 3264 if (ch == EOF || ch == (int)'\n') break; 3265 } 3266 } 3267 } 3268 fclose(fp); 3269 } 3270 3271 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3272 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3273 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3274 proper_unit_for_byte_size(large_page_size)); 3275 } 3276 3277 return large_page_size; 3278 } 3279 3280 size_t os::Linux::setup_large_page_size() { 3281 _large_page_size = Linux::find_large_page_size(); 3282 const size_t default_page_size = (size_t)Linux::page_size(); 3283 if (_large_page_size > default_page_size) { 3284 _page_sizes[0] = _large_page_size; 3285 _page_sizes[1] = default_page_size; 3286 _page_sizes[2] = 0; 3287 } 3288 3289 return _large_page_size; 3290 } 3291 3292 bool os::Linux::setup_large_page_type(size_t page_size) { 3293 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3294 FLAG_IS_DEFAULT(UseSHM) && 3295 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3296 3297 // The type of large pages has not been specified by the user. 3298 3299 // Try UseHugeTLBFS and then UseSHM. 3300 UseHugeTLBFS = UseSHM = true; 3301 3302 // Don't try UseTransparentHugePages since there are known 3303 // performance issues with it turned on. This might change in the future. 3304 UseTransparentHugePages = false; 3305 } 3306 3307 if (UseTransparentHugePages) { 3308 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3309 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3310 UseHugeTLBFS = false; 3311 UseSHM = false; 3312 return true; 3313 } 3314 UseTransparentHugePages = false; 3315 } 3316 3317 if (UseHugeTLBFS) { 3318 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3319 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3320 UseSHM = false; 3321 return true; 3322 } 3323 UseHugeTLBFS = false; 3324 } 3325 3326 return UseSHM; 3327 } 3328 3329 void os::large_page_init() { 3330 if (!UseLargePages && 3331 !UseTransparentHugePages && 3332 !UseHugeTLBFS && 3333 !UseSHM) { 3334 // Not using large pages. 3335 return; 3336 } 3337 3338 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3339 // The user explicitly turned off large pages. 3340 // Ignore the rest of the large pages flags. 3341 UseTransparentHugePages = false; 3342 UseHugeTLBFS = false; 3343 UseSHM = false; 3344 return; 3345 } 3346 3347 size_t large_page_size = Linux::setup_large_page_size(); 3348 UseLargePages = Linux::setup_large_page_type(large_page_size); 3349 3350 set_coredump_filter(); 3351 } 3352 3353 #ifndef SHM_HUGETLB 3354 #define SHM_HUGETLB 04000 3355 #endif 3356 3357 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) { 3358 // "exec" is passed in but not used. Creating the shared image for 3359 // the code cache doesn't have an SHM_X executable permission to check. 3360 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3361 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3362 3363 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3364 return NULL; // Fallback to small pages. 3365 } 3366 3367 key_t key = IPC_PRIVATE; 3368 char *addr; 3369 3370 bool warn_on_failure = UseLargePages && 3371 (!FLAG_IS_DEFAULT(UseLargePages) || 3372 !FLAG_IS_DEFAULT(UseSHM) || 3373 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3374 ); 3375 char msg[128]; 3376 3377 // Create a large shared memory region to attach to based on size. 3378 // Currently, size is the total size of the heap 3379 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3380 if (shmid == -1) { 3381 // Possible reasons for shmget failure: 3382 // 1. shmmax is too small for Java heap. 3383 // > check shmmax value: cat /proc/sys/kernel/shmmax 3384 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3385 // 2. not enough large page memory. 3386 // > check available large pages: cat /proc/meminfo 3387 // > increase amount of large pages: 3388 // echo new_value > /proc/sys/vm/nr_hugepages 3389 // Note 1: different Linux may use different name for this property, 3390 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3391 // Note 2: it's possible there's enough physical memory available but 3392 // they are so fragmented after a long run that they can't 3393 // coalesce into large pages. Try to reserve large pages when 3394 // the system is still "fresh". 3395 if (warn_on_failure) { 3396 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3397 warning("%s", msg); 3398 } 3399 return NULL; 3400 } 3401 3402 // attach to the region 3403 addr = (char*)shmat(shmid, req_addr, 0); 3404 int err = errno; 3405 3406 // Remove shmid. If shmat() is successful, the actual shared memory segment 3407 // will be deleted when it's detached by shmdt() or when the process 3408 // terminates. If shmat() is not successful this will remove the shared 3409 // segment immediately. 3410 shmctl(shmid, IPC_RMID, NULL); 3411 3412 if ((intptr_t)addr == -1) { 3413 if (warn_on_failure) { 3414 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3415 warning("%s", msg); 3416 } 3417 return NULL; 3418 } 3419 3420 return addr; 3421 } 3422 3423 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) { 3424 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3425 3426 bool warn_on_failure = UseLargePages && 3427 (!FLAG_IS_DEFAULT(UseLargePages) || 3428 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3429 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3430 3431 if (warn_on_failure) { 3432 char msg[128]; 3433 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3434 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3435 warning("%s", msg); 3436 } 3437 } 3438 3439 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) { 3440 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3441 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3442 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3443 3444 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3445 char* addr = (char*)::mmap(req_addr, bytes, prot, 3446 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3447 -1, 0); 3448 3449 if (addr == MAP_FAILED) { 3450 warn_on_large_pages_failure(req_addr, bytes, errno); 3451 return NULL; 3452 } 3453 3454 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3455 3456 return addr; 3457 } 3458 3459 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) { 3460 size_t large_page_size = os::large_page_size(); 3461 3462 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3463 3464 // Allocate small pages. 3465 3466 char* start; 3467 if (req_addr != NULL) { 3468 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3469 assert(is_size_aligned(bytes, alignment), "Must be"); 3470 start = os::reserve_memory(bytes, req_addr); 3471 assert(start == NULL || start == req_addr, "Must be"); 3472 } else { 3473 start = os::reserve_memory_aligned(bytes, alignment); 3474 } 3475 3476 if (start == NULL) { 3477 return NULL; 3478 } 3479 3480 assert(is_ptr_aligned(start, alignment), "Must be"); 3481 3482 if (MemTracker::tracking_level() > NMT_minimal) { 3483 // os::reserve_memory_special will record this memory area. 3484 // Need to release it here to prevent overlapping reservations. 3485 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3486 tkr.record((address)start, bytes); 3487 } 3488 3489 char* end = start + bytes; 3490 3491 // Find the regions of the allocated chunk that can be promoted to large pages. 3492 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3493 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3494 3495 size_t lp_bytes = lp_end - lp_start; 3496 3497 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3498 3499 if (lp_bytes == 0) { 3500 // The mapped region doesn't even span the start and the end of a large page. 3501 // Fall back to allocate a non-special area. 3502 ::munmap(start, end - start); 3503 return NULL; 3504 } 3505 3506 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3507 3508 3509 void* result; 3510 3511 if (start != lp_start) { 3512 result = ::mmap(start, lp_start - start, prot, 3513 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3514 -1, 0); 3515 if (result == MAP_FAILED) { 3516 ::munmap(lp_start, end - lp_start); 3517 return NULL; 3518 } 3519 } 3520 3521 result = ::mmap(lp_start, lp_bytes, prot, 3522 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3523 -1, 0); 3524 if (result == MAP_FAILED) { 3525 warn_on_large_pages_failure(req_addr, bytes, errno); 3526 // If the mmap above fails, the large pages region will be unmapped and we 3527 // have regions before and after with small pages. Release these regions. 3528 // 3529 // | mapped | unmapped | mapped | 3530 // ^ ^ ^ ^ 3531 // start lp_start lp_end end 3532 // 3533 ::munmap(start, lp_start - start); 3534 ::munmap(lp_end, end - lp_end); 3535 return NULL; 3536 } 3537 3538 if (lp_end != end) { 3539 result = ::mmap(lp_end, end - lp_end, prot, 3540 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3541 -1, 0); 3542 if (result == MAP_FAILED) { 3543 ::munmap(start, lp_end - start); 3544 return NULL; 3545 } 3546 } 3547 3548 return start; 3549 } 3550 3551 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) { 3552 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3553 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3554 assert(is_power_of_2(alignment), "Must be"); 3555 assert(is_power_of_2(os::large_page_size()), "Must be"); 3556 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3557 3558 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3559 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3560 } else { 3561 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3562 } 3563 } 3564 3565 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) { 3566 assert(UseLargePages, "only for large pages"); 3567 3568 char* addr; 3569 if (UseSHM) { 3570 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3571 } else { 3572 assert(UseHugeTLBFS, "must be"); 3573 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3574 } 3575 3576 if (addr != NULL) { 3577 if (UseNUMAInterleaving) { 3578 numa_make_global(addr, bytes); 3579 } 3580 3581 // The memory is committed 3582 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3583 } 3584 3585 return addr; 3586 } 3587 3588 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3589 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3590 return shmdt(base) == 0; 3591 } 3592 3593 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3594 return pd_release_memory(base, bytes); 3595 } 3596 3597 bool os::release_memory_special(char* base, size_t bytes) { 3598 bool res; 3599 if (MemTracker::tracking_level() > NMT_minimal) { 3600 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3601 res = os::Linux::release_memory_special_impl(base, bytes); 3602 if (res) { 3603 tkr.record((address)base, bytes); 3604 } 3605 3606 } else { 3607 res = os::Linux::release_memory_special_impl(base, bytes); 3608 } 3609 return res; 3610 } 3611 3612 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3613 assert(UseLargePages, "only for large pages"); 3614 bool res; 3615 3616 if (UseSHM) { 3617 res = os::Linux::release_memory_special_shm(base, bytes); 3618 } else { 3619 assert(UseHugeTLBFS, "must be"); 3620 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3621 } 3622 return res; 3623 } 3624 3625 size_t os::large_page_size() { 3626 return _large_page_size; 3627 } 3628 3629 // With SysV SHM the entire memory region must be allocated as shared 3630 // memory. 3631 // HugeTLBFS allows application to commit large page memory on demand. 3632 // However, when committing memory with HugeTLBFS fails, the region 3633 // that was supposed to be committed will lose the old reservation 3634 // and allow other threads to steal that memory region. Because of this 3635 // behavior we can't commit HugeTLBFS memory. 3636 bool os::can_commit_large_page_memory() { 3637 return UseTransparentHugePages; 3638 } 3639 3640 bool os::can_execute_large_page_memory() { 3641 return UseTransparentHugePages || UseHugeTLBFS; 3642 } 3643 3644 // Reserve memory at an arbitrary address, only if that area is 3645 // available (and not reserved for something else). 3646 3647 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3648 const int max_tries = 10; 3649 char* base[max_tries]; 3650 size_t size[max_tries]; 3651 const size_t gap = 0x000000; 3652 3653 // Assert only that the size is a multiple of the page size, since 3654 // that's all that mmap requires, and since that's all we really know 3655 // about at this low abstraction level. If we need higher alignment, 3656 // we can either pass an alignment to this method or verify alignment 3657 // in one of the methods further up the call chain. See bug 5044738. 3658 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3659 3660 // Repeatedly allocate blocks until the block is allocated at the 3661 // right spot. Give up after max_tries. Note that reserve_memory() will 3662 // automatically update _highest_vm_reserved_address if the call is 3663 // successful. The variable tracks the highest memory address every reserved 3664 // by JVM. It is used to detect heap-stack collision if running with 3665 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3666 // space than needed, it could confuse the collision detecting code. To 3667 // solve the problem, save current _highest_vm_reserved_address and 3668 // calculate the correct value before return. 3669 address old_highest = _highest_vm_reserved_address; 3670 3671 // Linux mmap allows caller to pass an address as hint; give it a try first, 3672 // if kernel honors the hint then we can return immediately. 3673 char * addr = anon_mmap(requested_addr, bytes, false); 3674 if (addr == requested_addr) { 3675 return requested_addr; 3676 } 3677 3678 if (addr != NULL) { 3679 // mmap() is successful but it fails to reserve at the requested address 3680 anon_munmap(addr, bytes); 3681 } 3682 3683 int i; 3684 for (i = 0; i < max_tries; ++i) { 3685 base[i] = reserve_memory(bytes); 3686 3687 if (base[i] != NULL) { 3688 // Is this the block we wanted? 3689 if (base[i] == requested_addr) { 3690 size[i] = bytes; 3691 break; 3692 } 3693 3694 // Does this overlap the block we wanted? Give back the overlapped 3695 // parts and try again. 3696 3697 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3698 if (top_overlap >= 0 && top_overlap < bytes) { 3699 unmap_memory(base[i], top_overlap); 3700 base[i] += top_overlap; 3701 size[i] = bytes - top_overlap; 3702 } else { 3703 size_t bottom_overlap = base[i] + bytes - requested_addr; 3704 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3705 unmap_memory(requested_addr, bottom_overlap); 3706 size[i] = bytes - bottom_overlap; 3707 } else { 3708 size[i] = bytes; 3709 } 3710 } 3711 } 3712 } 3713 3714 // Give back the unused reserved pieces. 3715 3716 for (int j = 0; j < i; ++j) { 3717 if (base[j] != NULL) { 3718 unmap_memory(base[j], size[j]); 3719 } 3720 } 3721 3722 if (i < max_tries) { 3723 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3724 return requested_addr; 3725 } else { 3726 _highest_vm_reserved_address = old_highest; 3727 return NULL; 3728 } 3729 } 3730 3731 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3732 return ::read(fd, buf, nBytes); 3733 } 3734 3735 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3736 // Solaris uses poll(), linux uses park(). 3737 // Poll() is likely a better choice, assuming that Thread.interrupt() 3738 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3739 // SIGSEGV, see 4355769. 3740 3741 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3742 assert(thread == Thread::current(), "thread consistency check"); 3743 3744 ParkEvent * const slp = thread->_SleepEvent ; 3745 slp->reset() ; 3746 OrderAccess::fence() ; 3747 3748 if (interruptible) { 3749 jlong prevtime = javaTimeNanos(); 3750 3751 for (;;) { 3752 if (os::is_interrupted(thread, true)) { 3753 return OS_INTRPT; 3754 } 3755 3756 jlong newtime = javaTimeNanos(); 3757 3758 if (newtime - prevtime < 0) { 3759 // time moving backwards, should only happen if no monotonic clock 3760 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3761 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3762 } else { 3763 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3764 } 3765 3766 if(millis <= 0) { 3767 return OS_OK; 3768 } 3769 3770 prevtime = newtime; 3771 3772 { 3773 assert(thread->is_Java_thread(), "sanity check"); 3774 JavaThread *jt = (JavaThread *) thread; 3775 ThreadBlockInVM tbivm(jt); 3776 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3777 3778 jt->set_suspend_equivalent(); 3779 // cleared by handle_special_suspend_equivalent_condition() or 3780 // java_suspend_self() via check_and_wait_while_suspended() 3781 3782 slp->park(millis); 3783 3784 // were we externally suspended while we were waiting? 3785 jt->check_and_wait_while_suspended(); 3786 } 3787 } 3788 } else { 3789 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3790 jlong prevtime = javaTimeNanos(); 3791 3792 for (;;) { 3793 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3794 // the 1st iteration ... 3795 jlong newtime = javaTimeNanos(); 3796 3797 if (newtime - prevtime < 0) { 3798 // time moving backwards, should only happen if no monotonic clock 3799 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3800 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3801 } else { 3802 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3803 } 3804 3805 if(millis <= 0) break ; 3806 3807 prevtime = newtime; 3808 slp->park(millis); 3809 } 3810 return OS_OK ; 3811 } 3812 } 3813 3814 // 3815 // Short sleep, direct OS call. 3816 // 3817 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3818 // sched_yield(2) will actually give up the CPU: 3819 // 3820 // * Alone on this pariticular CPU, keeps running. 3821 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3822 // (pre 2.6.39). 3823 // 3824 // So calling this with 0 is an alternative. 3825 // 3826 void os::naked_short_sleep(jlong ms) { 3827 struct timespec req; 3828 3829 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3830 req.tv_sec = 0; 3831 if (ms > 0) { 3832 req.tv_nsec = (ms % 1000) * 1000000; 3833 } 3834 else { 3835 req.tv_nsec = 1; 3836 } 3837 3838 nanosleep(&req, NULL); 3839 3840 return; 3841 } 3842 3843 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3844 void os::infinite_sleep() { 3845 while (true) { // sleep forever ... 3846 ::sleep(100); // ... 100 seconds at a time 3847 } 3848 } 3849 3850 // Used to convert frequent JVM_Yield() to nops 3851 bool os::dont_yield() { 3852 return DontYieldALot; 3853 } 3854 3855 void os::yield() { 3856 sched_yield(); 3857 } 3858 3859 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3860 3861 void os::yield_all(int attempts) { 3862 // Yields to all threads, including threads with lower priorities 3863 // Threads on Linux are all with same priority. The Solaris style 3864 // os::yield_all() with nanosleep(1ms) is not necessary. 3865 sched_yield(); 3866 } 3867 3868 // Called from the tight loops to possibly influence time-sharing heuristics 3869 void os::loop_breaker(int attempts) { 3870 os::yield_all(attempts); 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, int *priority_ptr) { 3936 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3937 *priority_ptr = java_to_os_priority[NormPriority]; 3938 return OS_OK; 3939 } 3940 3941 errno = 0; 3942 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3943 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3944 } 3945 3946 // Hint to the underlying OS that a task switch would not be good. 3947 // Void return because it's a hint and can fail. 3948 void os::hint_no_preempt() {} 3949 3950 //////////////////////////////////////////////////////////////////////////////// 3951 // suspend/resume support 3952 3953 // the low-level signal-based suspend/resume support is a remnant from the 3954 // old VM-suspension that used to be for java-suspension, safepoints etc, 3955 // within hotspot. Now there is a single use-case for this: 3956 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3957 // that runs in the watcher thread. 3958 // The remaining code is greatly simplified from the more general suspension 3959 // code that used to be used. 3960 // 3961 // The protocol is quite simple: 3962 // - suspend: 3963 // - sends a signal to the target thread 3964 // - polls the suspend state of the osthread using a yield loop 3965 // - target thread signal handler (SR_handler) sets suspend state 3966 // and blocks in sigsuspend until continued 3967 // - resume: 3968 // - sets target osthread state to continue 3969 // - sends signal to end the sigsuspend loop in the SR_handler 3970 // 3971 // Note that the SR_lock plays no role in this suspend/resume protocol. 3972 // 3973 3974 static void resume_clear_context(OSThread *osthread) { 3975 osthread->set_ucontext(NULL); 3976 osthread->set_siginfo(NULL); 3977 } 3978 3979 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3980 osthread->set_ucontext(context); 3981 osthread->set_siginfo(siginfo); 3982 } 3983 3984 // 3985 // Handler function invoked when a thread's execution is suspended or 3986 // resumed. We have to be careful that only async-safe functions are 3987 // called here (Note: most pthread functions are not async safe and 3988 // should be avoided.) 3989 // 3990 // Note: sigwait() is a more natural fit than sigsuspend() from an 3991 // interface point of view, but sigwait() prevents the signal hander 3992 // from being run. libpthread would get very confused by not having 3993 // its signal handlers run and prevents sigwait()'s use with the 3994 // mutex granting granting signal. 3995 // 3996 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3997 // 3998 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3999 // Save and restore errno to avoid confusing native code with EINTR 4000 // after sigsuspend. 4001 int old_errno = errno; 4002 4003 Thread* thread = Thread::current(); 4004 OSThread* osthread = thread->osthread(); 4005 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4006 4007 os::SuspendResume::State current = osthread->sr.state(); 4008 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4009 suspend_save_context(osthread, siginfo, context); 4010 4011 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4012 os::SuspendResume::State state = osthread->sr.suspended(); 4013 if (state == os::SuspendResume::SR_SUSPENDED) { 4014 sigset_t suspend_set; // signals for sigsuspend() 4015 4016 // get current set of blocked signals and unblock resume signal 4017 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4018 sigdelset(&suspend_set, SR_signum); 4019 4020 sr_semaphore.signal(); 4021 // wait here until we are resumed 4022 while (1) { 4023 sigsuspend(&suspend_set); 4024 4025 os::SuspendResume::State result = osthread->sr.running(); 4026 if (result == os::SuspendResume::SR_RUNNING) { 4027 sr_semaphore.signal(); 4028 break; 4029 } 4030 } 4031 4032 } else if (state == os::SuspendResume::SR_RUNNING) { 4033 // request was cancelled, continue 4034 } else { 4035 ShouldNotReachHere(); 4036 } 4037 4038 resume_clear_context(osthread); 4039 } else if (current == os::SuspendResume::SR_RUNNING) { 4040 // request was cancelled, continue 4041 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4042 // ignore 4043 } else { 4044 // ignore 4045 } 4046 4047 errno = old_errno; 4048 } 4049 4050 4051 static int SR_initialize() { 4052 struct sigaction act; 4053 char *s; 4054 /* Get signal number to use for suspend/resume */ 4055 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4056 int sig = ::strtol(s, 0, 10); 4057 if (sig > 0 || sig < _NSIG) { 4058 SR_signum = sig; 4059 } 4060 } 4061 4062 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4063 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4064 4065 sigemptyset(&SR_sigset); 4066 sigaddset(&SR_sigset, SR_signum); 4067 4068 /* Set up signal handler for suspend/resume */ 4069 act.sa_flags = SA_RESTART|SA_SIGINFO; 4070 act.sa_handler = (void (*)(int)) SR_handler; 4071 4072 // SR_signum is blocked by default. 4073 // 4528190 - We also need to block pthread restart signal (32 on all 4074 // supported Linux platforms). Note that LinuxThreads need to block 4075 // this signal for all threads to work properly. So we don't have 4076 // to use hard-coded signal number when setting up the mask. 4077 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4078 4079 if (sigaction(SR_signum, &act, 0) == -1) { 4080 return -1; 4081 } 4082 4083 // Save signal flag 4084 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4085 return 0; 4086 } 4087 4088 static int sr_notify(OSThread* osthread) { 4089 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4090 assert_status(status == 0, status, "pthread_kill"); 4091 return status; 4092 } 4093 4094 // "Randomly" selected value for how long we want to spin 4095 // before bailing out on suspending a thread, also how often 4096 // we send a signal to a thread we want to resume 4097 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4098 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4099 4100 // returns true on success and false on error - really an error is fatal 4101 // but this seems the normal response to library errors 4102 static bool do_suspend(OSThread* osthread) { 4103 assert(osthread->sr.is_running(), "thread should be running"); 4104 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4105 4106 // mark as suspended and send signal 4107 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4108 // failed to switch, state wasn't running? 4109 ShouldNotReachHere(); 4110 return false; 4111 } 4112 4113 if (sr_notify(osthread) != 0) { 4114 ShouldNotReachHere(); 4115 } 4116 4117 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4118 while (true) { 4119 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4120 break; 4121 } else { 4122 // timeout 4123 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4124 if (cancelled == os::SuspendResume::SR_RUNNING) { 4125 return false; 4126 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4127 // make sure that we consume the signal on the semaphore as well 4128 sr_semaphore.wait(); 4129 break; 4130 } else { 4131 ShouldNotReachHere(); 4132 return false; 4133 } 4134 } 4135 } 4136 4137 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4138 return true; 4139 } 4140 4141 static void do_resume(OSThread* osthread) { 4142 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4143 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4144 4145 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4146 // failed to switch to WAKEUP_REQUEST 4147 ShouldNotReachHere(); 4148 return; 4149 } 4150 4151 while (true) { 4152 if (sr_notify(osthread) == 0) { 4153 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4154 if (osthread->sr.is_running()) { 4155 return; 4156 } 4157 } 4158 } else { 4159 ShouldNotReachHere(); 4160 } 4161 } 4162 4163 guarantee(osthread->sr.is_running(), "Must be running!"); 4164 } 4165 4166 //////////////////////////////////////////////////////////////////////////////// 4167 // interrupt support 4168 4169 void os::interrupt(Thread* thread) { 4170 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 4171 "possibility of dangling Thread pointer"); 4172 4173 OSThread* osthread = thread->osthread(); 4174 4175 if (!osthread->interrupted()) { 4176 osthread->set_interrupted(true); 4177 // More than one thread can get here with the same value of osthread, 4178 // resulting in multiple notifications. We do, however, want the store 4179 // to interrupted() to be visible to other threads before we execute unpark(). 4180 OrderAccess::fence(); 4181 ParkEvent * const slp = thread->_SleepEvent ; 4182 if (slp != NULL) slp->unpark() ; 4183 } 4184 4185 // For JSR166. Unpark even if interrupt status already was set 4186 if (thread->is_Java_thread()) 4187 ((JavaThread*)thread)->parker()->unpark(); 4188 4189 ParkEvent * ev = thread->_ParkEvent ; 4190 if (ev != NULL) ev->unpark() ; 4191 4192 } 4193 4194 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 4195 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 4196 "possibility of dangling Thread pointer"); 4197 4198 OSThread* osthread = thread->osthread(); 4199 4200 bool interrupted = osthread->interrupted(); 4201 4202 if (interrupted && clear_interrupted) { 4203 osthread->set_interrupted(false); 4204 // consider thread->_SleepEvent->reset() ... optional optimization 4205 } 4206 4207 return interrupted; 4208 } 4209 4210 /////////////////////////////////////////////////////////////////////////////////// 4211 // signal handling (except suspend/resume) 4212 4213 // This routine may be used by user applications as a "hook" to catch signals. 4214 // The user-defined signal handler must pass unrecognized signals to this 4215 // routine, and if it returns true (non-zero), then the signal handler must 4216 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4217 // routine will never retun false (zero), but instead will execute a VM panic 4218 // routine kill the process. 4219 // 4220 // If this routine returns false, it is OK to call it again. This allows 4221 // the user-defined signal handler to perform checks either before or after 4222 // the VM performs its own checks. Naturally, the user code would be making 4223 // a serious error if it tried to handle an exception (such as a null check 4224 // or breakpoint) that the VM was generating for its own correct operation. 4225 // 4226 // This routine may recognize any of the following kinds of signals: 4227 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4228 // It should be consulted by handlers for any of those signals. 4229 // 4230 // The caller of this routine must pass in the three arguments supplied 4231 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4232 // field of the structure passed to sigaction(). This routine assumes that 4233 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4234 // 4235 // Note that the VM will print warnings if it detects conflicting signal 4236 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4237 // 4238 extern "C" JNIEXPORT int 4239 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 4240 void* ucontext, int abort_if_unrecognized); 4241 4242 void signalHandler(int sig, siginfo_t* info, void* uc) { 4243 assert(info != NULL && uc != NULL, "it must be old kernel"); 4244 int orig_errno = errno; // Preserve errno value over signal handler. 4245 JVM_handle_linux_signal(sig, info, uc, true); 4246 errno = orig_errno; 4247 } 4248 4249 4250 // This boolean allows users to forward their own non-matching signals 4251 // to JVM_handle_linux_signal, harmlessly. 4252 bool os::Linux::signal_handlers_are_installed = false; 4253 4254 // For signal-chaining 4255 struct sigaction os::Linux::sigact[MAXSIGNUM]; 4256 unsigned int os::Linux::sigs = 0; 4257 bool os::Linux::libjsig_is_loaded = false; 4258 typedef struct sigaction *(*get_signal_t)(int); 4259 get_signal_t os::Linux::get_signal_action = NULL; 4260 4261 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4262 struct sigaction *actp = NULL; 4263 4264 if (libjsig_is_loaded) { 4265 // Retrieve the old signal handler from libjsig 4266 actp = (*get_signal_action)(sig); 4267 } 4268 if (actp == NULL) { 4269 // Retrieve the preinstalled signal handler from jvm 4270 actp = get_preinstalled_handler(sig); 4271 } 4272 4273 return actp; 4274 } 4275 4276 static bool call_chained_handler(struct sigaction *actp, int sig, 4277 siginfo_t *siginfo, void *context) { 4278 // Call the old signal handler 4279 if (actp->sa_handler == SIG_DFL) { 4280 // It's more reasonable to let jvm treat it as an unexpected exception 4281 // instead of taking the default action. 4282 return false; 4283 } else if (actp->sa_handler != SIG_IGN) { 4284 if ((actp->sa_flags & SA_NODEFER) == 0) { 4285 // automaticlly block the signal 4286 sigaddset(&(actp->sa_mask), sig); 4287 } 4288 4289 sa_handler_t hand; 4290 sa_sigaction_t sa; 4291 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4292 // retrieve the chained handler 4293 if (siginfo_flag_set) { 4294 sa = actp->sa_sigaction; 4295 } else { 4296 hand = actp->sa_handler; 4297 } 4298 4299 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4300 actp->sa_handler = SIG_DFL; 4301 } 4302 4303 // try to honor the signal mask 4304 sigset_t oset; 4305 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4306 4307 // call into the chained handler 4308 if (siginfo_flag_set) { 4309 (*sa)(sig, siginfo, context); 4310 } else { 4311 (*hand)(sig); 4312 } 4313 4314 // restore the signal mask 4315 pthread_sigmask(SIG_SETMASK, &oset, 0); 4316 } 4317 // Tell jvm's signal handler the signal is taken care of. 4318 return true; 4319 } 4320 4321 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4322 bool chained = false; 4323 // signal-chaining 4324 if (UseSignalChaining) { 4325 struct sigaction *actp = get_chained_signal_action(sig); 4326 if (actp != NULL) { 4327 chained = call_chained_handler(actp, sig, siginfo, context); 4328 } 4329 } 4330 return chained; 4331 } 4332 4333 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4334 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 4335 return &sigact[sig]; 4336 } 4337 return NULL; 4338 } 4339 4340 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4341 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4342 sigact[sig] = oldAct; 4343 sigs |= (unsigned int)1 << sig; 4344 } 4345 4346 // for diagnostic 4347 int os::Linux::sigflags[MAXSIGNUM]; 4348 4349 int os::Linux::get_our_sigflags(int sig) { 4350 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4351 return sigflags[sig]; 4352 } 4353 4354 void os::Linux::set_our_sigflags(int sig, int flags) { 4355 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4356 sigflags[sig] = flags; 4357 } 4358 4359 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4360 // Check for overwrite. 4361 struct sigaction oldAct; 4362 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4363 4364 void* oldhand = oldAct.sa_sigaction 4365 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4366 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4367 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4368 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4369 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4370 if (AllowUserSignalHandlers || !set_installed) { 4371 // Do not overwrite; user takes responsibility to forward to us. 4372 return; 4373 } else if (UseSignalChaining) { 4374 // save the old handler in jvm 4375 save_preinstalled_handler(sig, oldAct); 4376 // libjsig also interposes the sigaction() call below and saves the 4377 // old sigaction on it own. 4378 } else { 4379 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 4380 "%#lx for signal %d.", (long)oldhand, sig)); 4381 } 4382 } 4383 4384 struct sigaction sigAct; 4385 sigfillset(&(sigAct.sa_mask)); 4386 sigAct.sa_handler = SIG_DFL; 4387 if (!set_installed) { 4388 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4389 } else { 4390 sigAct.sa_sigaction = signalHandler; 4391 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4392 } 4393 // Save flags, which are set by ours 4394 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4395 sigflags[sig] = sigAct.sa_flags; 4396 4397 int ret = sigaction(sig, &sigAct, &oldAct); 4398 assert(ret == 0, "check"); 4399 4400 void* oldhand2 = oldAct.sa_sigaction 4401 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4402 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4403 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4404 } 4405 4406 // install signal handlers for signals that HotSpot needs to 4407 // handle in order to support Java-level exception handling. 4408 4409 void os::Linux::install_signal_handlers() { 4410 if (!signal_handlers_are_installed) { 4411 signal_handlers_are_installed = true; 4412 4413 // signal-chaining 4414 typedef void (*signal_setting_t)(); 4415 signal_setting_t begin_signal_setting = NULL; 4416 signal_setting_t end_signal_setting = NULL; 4417 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4418 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4419 if (begin_signal_setting != NULL) { 4420 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4421 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4422 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4423 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4424 libjsig_is_loaded = true; 4425 assert(UseSignalChaining, "should enable signal-chaining"); 4426 } 4427 if (libjsig_is_loaded) { 4428 // Tell libjsig jvm is setting signal handlers 4429 (*begin_signal_setting)(); 4430 } 4431 4432 set_signal_handler(SIGSEGV, true); 4433 set_signal_handler(SIGPIPE, true); 4434 set_signal_handler(SIGBUS, true); 4435 set_signal_handler(SIGILL, true); 4436 set_signal_handler(SIGFPE, true); 4437 #if defined(PPC64) 4438 set_signal_handler(SIGTRAP, true); 4439 #endif 4440 set_signal_handler(SIGXFSZ, true); 4441 4442 if (libjsig_is_loaded) { 4443 // Tell libjsig jvm finishes setting signal handlers 4444 (*end_signal_setting)(); 4445 } 4446 4447 // We don't activate signal checker if libjsig is in place, we trust ourselves 4448 // and if UserSignalHandler is installed all bets are off. 4449 // Log that signal checking is off only if -verbose:jni is specified. 4450 if (CheckJNICalls) { 4451 if (libjsig_is_loaded) { 4452 if (PrintJNIResolving) { 4453 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4454 } 4455 check_signals = false; 4456 } 4457 if (AllowUserSignalHandlers) { 4458 if (PrintJNIResolving) { 4459 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4460 } 4461 check_signals = false; 4462 } 4463 } 4464 } 4465 } 4466 4467 // This is the fastest way to get thread cpu time on Linux. 4468 // Returns cpu time (user+sys) for any thread, not only for current. 4469 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4470 // It might work on 2.6.10+ with a special kernel/glibc patch. 4471 // For reference, please, see IEEE Std 1003.1-2004: 4472 // http://www.unix.org/single_unix_specification 4473 4474 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4475 struct timespec tp; 4476 int rc = os::Linux::clock_gettime(clockid, &tp); 4477 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4478 4479 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4480 } 4481 4482 ///// 4483 // glibc on Linux platform uses non-documented flag 4484 // to indicate, that some special sort of signal 4485 // trampoline is used. 4486 // We will never set this flag, and we should 4487 // ignore this flag in our diagnostic 4488 #ifdef SIGNIFICANT_SIGNAL_MASK 4489 #undef SIGNIFICANT_SIGNAL_MASK 4490 #endif 4491 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4492 4493 static const char* get_signal_handler_name(address handler, 4494 char* buf, int buflen) { 4495 int offset; 4496 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4497 if (found) { 4498 // skip directory names 4499 const char *p1, *p2; 4500 p1 = buf; 4501 size_t len = strlen(os::file_separator()); 4502 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4503 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4504 } else { 4505 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4506 } 4507 return buf; 4508 } 4509 4510 static void print_signal_handler(outputStream* st, int sig, 4511 char* buf, size_t buflen) { 4512 struct sigaction sa; 4513 4514 sigaction(sig, NULL, &sa); 4515 4516 // See comment for SIGNIFICANT_SIGNAL_MASK define 4517 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4518 4519 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4520 4521 address handler = (sa.sa_flags & SA_SIGINFO) 4522 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4523 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4524 4525 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4526 st->print("SIG_DFL"); 4527 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4528 st->print("SIG_IGN"); 4529 } else { 4530 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4531 } 4532 4533 st->print(", sa_mask[0]="); 4534 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4535 4536 address rh = VMError::get_resetted_sighandler(sig); 4537 // May be, handler was resetted by VMError? 4538 if(rh != NULL) { 4539 handler = rh; 4540 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4541 } 4542 4543 st->print(", sa_flags="); 4544 os::Posix::print_sa_flags(st, sa.sa_flags); 4545 4546 // Check: is it our handler? 4547 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4548 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4549 // It is our signal handler 4550 // check for flags, reset system-used one! 4551 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4552 st->print( 4553 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4554 os::Linux::get_our_sigflags(sig)); 4555 } 4556 } 4557 st->cr(); 4558 } 4559 4560 4561 #define DO_SIGNAL_CHECK(sig) \ 4562 if (!sigismember(&check_signal_done, sig)) \ 4563 os::Linux::check_signal_handler(sig) 4564 4565 // This method is a periodic task to check for misbehaving JNI applications 4566 // under CheckJNI, we can add any periodic checks here 4567 4568 void os::run_periodic_checks() { 4569 4570 if (check_signals == false) return; 4571 4572 // SEGV and BUS if overridden could potentially prevent 4573 // generation of hs*.log in the event of a crash, debugging 4574 // such a case can be very challenging, so we absolutely 4575 // check the following for a good measure: 4576 DO_SIGNAL_CHECK(SIGSEGV); 4577 DO_SIGNAL_CHECK(SIGILL); 4578 DO_SIGNAL_CHECK(SIGFPE); 4579 DO_SIGNAL_CHECK(SIGBUS); 4580 DO_SIGNAL_CHECK(SIGPIPE); 4581 DO_SIGNAL_CHECK(SIGXFSZ); 4582 #if defined(PPC64) 4583 DO_SIGNAL_CHECK(SIGTRAP); 4584 #endif 4585 4586 // ReduceSignalUsage allows the user to override these handlers 4587 // see comments at the very top and jvm_solaris.h 4588 if (!ReduceSignalUsage) { 4589 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4590 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4591 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4592 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4593 } 4594 4595 DO_SIGNAL_CHECK(SR_signum); 4596 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4597 } 4598 4599 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4600 4601 static os_sigaction_t os_sigaction = NULL; 4602 4603 void os::Linux::check_signal_handler(int sig) { 4604 char buf[O_BUFLEN]; 4605 address jvmHandler = NULL; 4606 4607 4608 struct sigaction act; 4609 if (os_sigaction == NULL) { 4610 // only trust the default sigaction, in case it has been interposed 4611 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4612 if (os_sigaction == NULL) return; 4613 } 4614 4615 os_sigaction(sig, (struct sigaction*)NULL, &act); 4616 4617 4618 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4619 4620 address thisHandler = (act.sa_flags & SA_SIGINFO) 4621 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4622 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 4623 4624 4625 switch(sig) { 4626 case SIGSEGV: 4627 case SIGBUS: 4628 case SIGFPE: 4629 case SIGPIPE: 4630 case SIGILL: 4631 case SIGXFSZ: 4632 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4633 break; 4634 4635 case SHUTDOWN1_SIGNAL: 4636 case SHUTDOWN2_SIGNAL: 4637 case SHUTDOWN3_SIGNAL: 4638 case BREAK_SIGNAL: 4639 jvmHandler = (address)user_handler(); 4640 break; 4641 4642 case INTERRUPT_SIGNAL: 4643 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4644 break; 4645 4646 default: 4647 if (sig == SR_signum) { 4648 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4649 } else { 4650 return; 4651 } 4652 break; 4653 } 4654 4655 if (thisHandler != jvmHandler) { 4656 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4657 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4658 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4659 // No need to check this sig any longer 4660 sigaddset(&check_signal_done, sig); 4661 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4662 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4663 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4664 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4665 // No need to check this sig any longer 4666 sigaddset(&check_signal_done, sig); 4667 } 4668 4669 // Dump all the signal 4670 if (sigismember(&check_signal_done, sig)) { 4671 print_signal_handlers(tty, buf, O_BUFLEN); 4672 } 4673 } 4674 4675 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4676 4677 extern bool signal_name(int signo, char* buf, size_t len); 4678 4679 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4680 if (0 < exception_code && exception_code <= SIGRTMAX) { 4681 // signal 4682 if (!signal_name(exception_code, buf, size)) { 4683 jio_snprintf(buf, size, "SIG%d", exception_code); 4684 } 4685 return buf; 4686 } else { 4687 return NULL; 4688 } 4689 } 4690 4691 // this is called _before_ the most of global arguments have been parsed 4692 void os::init(void) { 4693 char dummy; /* used to get a guess on initial stack address */ 4694 // first_hrtime = gethrtime(); 4695 4696 // With LinuxThreads the JavaMain thread pid (primordial thread) 4697 // is different than the pid of the java launcher thread. 4698 // So, on Linux, the launcher thread pid is passed to the VM 4699 // via the sun.java.launcher.pid property. 4700 // Use this property instead of getpid() if it was correctly passed. 4701 // See bug 6351349. 4702 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4703 4704 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4705 4706 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4707 4708 init_random(1234567); 4709 4710 ThreadCritical::initialize(); 4711 4712 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4713 if (Linux::page_size() == -1) { 4714 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4715 strerror(errno))); 4716 } 4717 init_page_sizes((size_t) Linux::page_size()); 4718 4719 Linux::initialize_system_info(); 4720 4721 // main_thread points to the aboriginal thread 4722 Linux::_main_thread = pthread_self(); 4723 4724 Linux::clock_init(); 4725 initial_time_count = javaTimeNanos(); 4726 4727 // pthread_condattr initialization for monotonic clock 4728 int status; 4729 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4730 if ((status = pthread_condattr_init(_condattr)) != 0) { 4731 fatal(err_msg("pthread_condattr_init: %s", strerror(status))); 4732 } 4733 // Only set the clock if CLOCK_MONOTONIC is available 4734 if (Linux::supports_monotonic_clock()) { 4735 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4736 if (status == EINVAL) { 4737 warning("Unable to use monotonic clock with relative timed-waits" \ 4738 " - changes to the time-of-day clock may have adverse affects"); 4739 } else { 4740 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status))); 4741 } 4742 } 4743 } 4744 // else it defaults to CLOCK_REALTIME 4745 4746 pthread_mutex_init(&dl_mutex, NULL); 4747 4748 // If the pagesize of the VM is greater than 8K determine the appropriate 4749 // number of initial guard pages. The user can change this with the 4750 // command line arguments, if needed. 4751 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4752 StackYellowPages = 1; 4753 StackRedPages = 1; 4754 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4755 } 4756 } 4757 4758 // To install functions for atexit system call 4759 extern "C" { 4760 static void perfMemory_exit_helper() { 4761 perfMemory_exit(); 4762 } 4763 } 4764 4765 // this is called _after_ the global arguments have been parsed 4766 jint os::init_2(void) 4767 { 4768 Linux::fast_thread_clock_init(); 4769 4770 // Allocate a single page and mark it as readable for safepoint polling 4771 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4772 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4773 4774 os::set_polling_page( polling_page ); 4775 4776 #ifndef PRODUCT 4777 if(Verbose && PrintMiscellaneous) 4778 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4779 #endif 4780 4781 if (!UseMembar) { 4782 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4783 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4784 os::set_memory_serialize_page( mem_serialize_page ); 4785 4786 #ifndef PRODUCT 4787 if(Verbose && PrintMiscellaneous) 4788 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4789 #endif 4790 } 4791 4792 // initialize suspend/resume support - must do this before signal_sets_init() 4793 if (SR_initialize() != 0) { 4794 perror("SR_initialize failed"); 4795 return JNI_ERR; 4796 } 4797 4798 Linux::signal_sets_init(); 4799 Linux::install_signal_handlers(); 4800 4801 // Check minimum allowable stack size for thread creation and to initialize 4802 // the java system classes, including StackOverflowError - depends on page 4803 // size. Add a page for compiler2 recursion in main thread. 4804 // Add in 2*BytesPerWord times page size to account for VM stack during 4805 // class initialization depending on 32 or 64 bit VM. 4806 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4807 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4808 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4809 4810 size_t threadStackSizeInBytes = ThreadStackSize * K; 4811 if (threadStackSizeInBytes != 0 && 4812 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4813 tty->print_cr("\nThe stack size specified is too small, " 4814 "Specify at least %dk", 4815 os::Linux::min_stack_allowed/ K); 4816 return JNI_ERR; 4817 } 4818 4819 // Make the stack size a multiple of the page size so that 4820 // the yellow/red zones can be guarded. 4821 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4822 vm_page_size())); 4823 4824 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4825 4826 #if defined(IA32) 4827 workaround_expand_exec_shield_cs_limit(); 4828 #endif 4829 4830 Linux::libpthread_init(); 4831 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4832 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4833 Linux::glibc_version(), Linux::libpthread_version(), 4834 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4835 } 4836 4837 if (UseNUMA) { 4838 if (!Linux::libnuma_init()) { 4839 UseNUMA = false; 4840 } else { 4841 if ((Linux::numa_max_node() < 1)) { 4842 // There's only one node(they start from 0), disable NUMA. 4843 UseNUMA = false; 4844 } 4845 } 4846 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4847 // we can make the adaptive lgrp chunk resizing work. If the user specified 4848 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4849 // disable adaptive resizing. 4850 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4851 if (FLAG_IS_DEFAULT(UseNUMA)) { 4852 UseNUMA = false; 4853 } else { 4854 if (FLAG_IS_DEFAULT(UseLargePages) && 4855 FLAG_IS_DEFAULT(UseSHM) && 4856 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4857 UseLargePages = false; 4858 } else { 4859 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing"); 4860 UseAdaptiveSizePolicy = false; 4861 UseAdaptiveNUMAChunkSizing = false; 4862 } 4863 } 4864 } 4865 if (!UseNUMA && ForceNUMA) { 4866 UseNUMA = true; 4867 } 4868 } 4869 4870 if (MaxFDLimit) { 4871 // set the number of file descriptors to max. print out error 4872 // if getrlimit/setrlimit fails but continue regardless. 4873 struct rlimit nbr_files; 4874 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4875 if (status != 0) { 4876 if (PrintMiscellaneous && (Verbose || WizardMode)) 4877 perror("os::init_2 getrlimit failed"); 4878 } else { 4879 nbr_files.rlim_cur = nbr_files.rlim_max; 4880 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4881 if (status != 0) { 4882 if (PrintMiscellaneous && (Verbose || WizardMode)) 4883 perror("os::init_2 setrlimit failed"); 4884 } 4885 } 4886 } 4887 4888 // Initialize lock used to serialize thread creation (see os::create_thread) 4889 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4890 4891 // at-exit methods are called in the reverse order of their registration. 4892 // atexit functions are called on return from main or as a result of a 4893 // call to exit(3C). There can be only 32 of these functions registered 4894 // and atexit() does not set errno. 4895 4896 if (PerfAllowAtExitRegistration) { 4897 // only register atexit functions if PerfAllowAtExitRegistration is set. 4898 // atexit functions can be delayed until process exit time, which 4899 // can be problematic for embedded VM situations. Embedded VMs should 4900 // call DestroyJavaVM() to assure that VM resources are released. 4901 4902 // note: perfMemory_exit_helper atexit function may be removed in 4903 // the future if the appropriate cleanup code can be added to the 4904 // VM_Exit VMOperation's doit method. 4905 if (atexit(perfMemory_exit_helper) != 0) { 4906 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4907 } 4908 } 4909 4910 // initialize thread priority policy 4911 prio_init(); 4912 4913 return JNI_OK; 4914 } 4915 4916 // this is called at the end of vm_initialization 4917 void os::init_3(void) { 4918 #ifdef JAVASE_EMBEDDED 4919 // Start the MemNotifyThread 4920 if (LowMemoryProtection) { 4921 MemNotifyThread::start(); 4922 } 4923 return; 4924 #endif 4925 } 4926 4927 // Mark the polling page as unreadable 4928 void os::make_polling_page_unreadable(void) { 4929 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4930 fatal("Could not disable polling page"); 4931 }; 4932 4933 // Mark the polling page as readable 4934 void os::make_polling_page_readable(void) { 4935 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4936 fatal("Could not enable polling page"); 4937 } 4938 }; 4939 4940 int os::active_processor_count() { 4941 // Linux doesn't yet have a (official) notion of processor sets, 4942 // so just return the number of online processors. 4943 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4944 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4945 return online_cpus; 4946 } 4947 4948 void os::set_native_thread_name(const char *name) { 4949 // Not yet implemented. 4950 return; 4951 } 4952 4953 bool os::distribute_processes(uint length, uint* distribution) { 4954 // Not yet implemented. 4955 return false; 4956 } 4957 4958 bool os::bind_to_processor(uint processor_id) { 4959 // Not yet implemented. 4960 return false; 4961 } 4962 4963 /// 4964 4965 void os::SuspendedThreadTask::internal_do_task() { 4966 if (do_suspend(_thread->osthread())) { 4967 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4968 do_task(context); 4969 do_resume(_thread->osthread()); 4970 } 4971 } 4972 4973 class PcFetcher : public os::SuspendedThreadTask { 4974 public: 4975 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4976 ExtendedPC result(); 4977 protected: 4978 void do_task(const os::SuspendedThreadTaskContext& context); 4979 private: 4980 ExtendedPC _epc; 4981 }; 4982 4983 ExtendedPC PcFetcher::result() { 4984 guarantee(is_done(), "task is not done yet."); 4985 return _epc; 4986 } 4987 4988 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4989 Thread* thread = context.thread(); 4990 OSThread* osthread = thread->osthread(); 4991 if (osthread->ucontext() != NULL) { 4992 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext()); 4993 } else { 4994 // NULL context is unexpected, double-check this is the VMThread 4995 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4996 } 4997 } 4998 4999 // Suspends the target using the signal mechanism and then grabs the PC before 5000 // resuming the target. Used by the flat-profiler only 5001 ExtendedPC os::get_thread_pc(Thread* thread) { 5002 // Make sure that it is called by the watcher for the VMThread 5003 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 5004 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 5005 5006 PcFetcher fetcher(thread); 5007 fetcher.run(); 5008 return fetcher.result(); 5009 } 5010 5011 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 5012 { 5013 if (is_NPTL()) { 5014 return pthread_cond_timedwait(_cond, _mutex, _abstime); 5015 } else { 5016 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 5017 // word back to default 64bit precision if condvar is signaled. Java 5018 // wants 53bit precision. Save and restore current value. 5019 int fpu = get_fpu_control_word(); 5020 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 5021 set_fpu_control_word(fpu); 5022 return status; 5023 } 5024 } 5025 5026 //////////////////////////////////////////////////////////////////////////////// 5027 // debug support 5028 5029 bool os::find(address addr, outputStream* st) { 5030 Dl_info dlinfo; 5031 memset(&dlinfo, 0, sizeof(dlinfo)); 5032 if (dladdr(addr, &dlinfo) != 0) { 5033 st->print(PTR_FORMAT ": ", addr); 5034 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5035 st->print("%s+%#x", dlinfo.dli_sname, 5036 addr - (intptr_t)dlinfo.dli_saddr); 5037 } else if (dlinfo.dli_fbase != NULL) { 5038 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 5039 } else { 5040 st->print("<absolute address>"); 5041 } 5042 if (dlinfo.dli_fname != NULL) { 5043 st->print(" in %s", dlinfo.dli_fname); 5044 } 5045 if (dlinfo.dli_fbase != NULL) { 5046 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 5047 } 5048 st->cr(); 5049 5050 if (Verbose) { 5051 // decode some bytes around the PC 5052 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5053 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5054 address lowest = (address) dlinfo.dli_sname; 5055 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5056 if (begin < lowest) begin = lowest; 5057 Dl_info dlinfo2; 5058 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5059 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 5060 end = (address) dlinfo2.dli_saddr; 5061 Disassembler::decode(begin, end, st); 5062 } 5063 return true; 5064 } 5065 return false; 5066 } 5067 5068 //////////////////////////////////////////////////////////////////////////////// 5069 // misc 5070 5071 // This does not do anything on Linux. This is basically a hook for being 5072 // able to use structured exception handling (thread-local exception filters) 5073 // on, e.g., Win32. 5074 void 5075 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 5076 JavaCallArguments* args, Thread* thread) { 5077 f(value, method, args, thread); 5078 } 5079 5080 void os::print_statistics() { 5081 } 5082 5083 int os::message_box(const char* title, const char* message) { 5084 int i; 5085 fdStream err(defaultStream::error_fd()); 5086 for (i = 0; i < 78; i++) err.print_raw("="); 5087 err.cr(); 5088 err.print_raw_cr(title); 5089 for (i = 0; i < 78; i++) err.print_raw("-"); 5090 err.cr(); 5091 err.print_raw_cr(message); 5092 for (i = 0; i < 78; i++) err.print_raw("="); 5093 err.cr(); 5094 5095 char buf[16]; 5096 // Prevent process from exiting upon "read error" without consuming all CPU 5097 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5098 5099 return buf[0] == 'y' || buf[0] == 'Y'; 5100 } 5101 5102 int os::stat(const char *path, struct stat *sbuf) { 5103 char pathbuf[MAX_PATH]; 5104 if (strlen(path) > MAX_PATH - 1) { 5105 errno = ENAMETOOLONG; 5106 return -1; 5107 } 5108 os::native_path(strcpy(pathbuf, path)); 5109 return ::stat(pathbuf, sbuf); 5110 } 5111 5112 bool os::check_heap(bool force) { 5113 return true; 5114 } 5115 5116 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 5117 return ::vsnprintf(buf, count, format, args); 5118 } 5119 5120 // Is a (classpath) directory empty? 5121 bool os::dir_is_empty(const char* path) { 5122 DIR *dir = NULL; 5123 struct dirent *ptr; 5124 5125 dir = opendir(path); 5126 if (dir == NULL) return true; 5127 5128 /* Scan the directory */ 5129 bool result = true; 5130 char buf[sizeof(struct dirent) + MAX_PATH]; 5131 while (result && (ptr = ::readdir(dir)) != NULL) { 5132 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5133 result = false; 5134 } 5135 } 5136 closedir(dir); 5137 return result; 5138 } 5139 5140 // This code originates from JDK's sysOpen and open64_w 5141 // from src/solaris/hpi/src/system_md.c 5142 5143 #ifndef O_DELETE 5144 #define O_DELETE 0x10000 5145 #endif 5146 5147 // Open a file. Unlink the file immediately after open returns 5148 // if the specified oflag has the O_DELETE flag set. 5149 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 5150 5151 int os::open(const char *path, int oflag, int mode) { 5152 5153 if (strlen(path) > MAX_PATH - 1) { 5154 errno = ENAMETOOLONG; 5155 return -1; 5156 } 5157 int fd; 5158 int o_delete = (oflag & O_DELETE); 5159 oflag = oflag & ~O_DELETE; 5160 5161 fd = ::open64(path, oflag, mode); 5162 if (fd == -1) return -1; 5163 5164 //If the open succeeded, the file might still be a directory 5165 { 5166 struct stat64 buf64; 5167 int ret = ::fstat64(fd, &buf64); 5168 int st_mode = buf64.st_mode; 5169 5170 if (ret != -1) { 5171 if ((st_mode & S_IFMT) == S_IFDIR) { 5172 errno = EISDIR; 5173 ::close(fd); 5174 return -1; 5175 } 5176 } else { 5177 ::close(fd); 5178 return -1; 5179 } 5180 } 5181 5182 /* 5183 * All file descriptors that are opened in the JVM and not 5184 * specifically destined for a subprocess should have the 5185 * close-on-exec flag set. If we don't set it, then careless 3rd 5186 * party native code might fork and exec without closing all 5187 * appropriate file descriptors (e.g. as we do in closeDescriptors in 5188 * UNIXProcess.c), and this in turn might: 5189 * 5190 * - cause end-of-file to fail to be detected on some file 5191 * descriptors, resulting in mysterious hangs, or 5192 * 5193 * - might cause an fopen in the subprocess to fail on a system 5194 * suffering from bug 1085341. 5195 * 5196 * (Yes, the default setting of the close-on-exec flag is a Unix 5197 * design flaw) 5198 * 5199 * See: 5200 * 1085341: 32-bit stdio routines should support file descriptors >255 5201 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5202 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5203 */ 5204 #ifdef FD_CLOEXEC 5205 { 5206 int flags = ::fcntl(fd, F_GETFD); 5207 if (flags != -1) 5208 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5209 } 5210 #endif 5211 5212 if (o_delete != 0) { 5213 ::unlink(path); 5214 } 5215 return fd; 5216 } 5217 5218 5219 // create binary file, rewriting existing file if required 5220 int os::create_binary_file(const char* path, bool rewrite_existing) { 5221 int oflags = O_WRONLY | O_CREAT; 5222 if (!rewrite_existing) { 5223 oflags |= O_EXCL; 5224 } 5225 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5226 } 5227 5228 // return current position of file pointer 5229 jlong os::current_file_offset(int fd) { 5230 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5231 } 5232 5233 // move file pointer to the specified offset 5234 jlong os::seek_to_file_offset(int fd, jlong offset) { 5235 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5236 } 5237 5238 // This code originates from JDK's sysAvailable 5239 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5240 5241 int os::available(int fd, jlong *bytes) { 5242 jlong cur, end; 5243 int mode; 5244 struct stat64 buf64; 5245 5246 if (::fstat64(fd, &buf64) >= 0) { 5247 mode = buf64.st_mode; 5248 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5249 /* 5250 * XXX: is the following call interruptible? If so, this might 5251 * need to go through the INTERRUPT_IO() wrapper as for other 5252 * blocking, interruptible calls in this file. 5253 */ 5254 int n; 5255 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5256 *bytes = n; 5257 return 1; 5258 } 5259 } 5260 } 5261 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5262 return 0; 5263 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5264 return 0; 5265 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5266 return 0; 5267 } 5268 *bytes = end - cur; 5269 return 1; 5270 } 5271 5272 int os::socket_available(int fd, jint *pbytes) { 5273 // Linux doc says EINTR not returned, unlike Solaris 5274 int ret = ::ioctl(fd, FIONREAD, pbytes); 5275 5276 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 5277 // is expected to return 0 on failure and 1 on success to the jdk. 5278 return (ret < 0) ? 0 : 1; 5279 } 5280 5281 // Map a block of memory. 5282 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5283 char *addr, size_t bytes, bool read_only, 5284 bool allow_exec) { 5285 int prot; 5286 int flags = MAP_PRIVATE; 5287 5288 if (read_only) { 5289 prot = PROT_READ; 5290 } else { 5291 prot = PROT_READ | PROT_WRITE; 5292 } 5293 5294 if (allow_exec) { 5295 prot |= PROT_EXEC; 5296 } 5297 5298 if (addr != NULL) { 5299 flags |= MAP_FIXED; 5300 } 5301 5302 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5303 fd, file_offset); 5304 if (mapped_address == MAP_FAILED) { 5305 return NULL; 5306 } 5307 return mapped_address; 5308 } 5309 5310 5311 // Remap a block of memory. 5312 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5313 char *addr, size_t bytes, bool read_only, 5314 bool allow_exec) { 5315 // same as map_memory() on this OS 5316 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5317 allow_exec); 5318 } 5319 5320 5321 // Unmap a block of memory. 5322 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5323 return munmap(addr, bytes) == 0; 5324 } 5325 5326 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5327 5328 static clockid_t thread_cpu_clockid(Thread* thread) { 5329 pthread_t tid = thread->osthread()->pthread_id(); 5330 clockid_t clockid; 5331 5332 // Get thread clockid 5333 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5334 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5335 return clockid; 5336 } 5337 5338 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5339 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5340 // of a thread. 5341 // 5342 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5343 // the fast estimate available on the platform. 5344 5345 jlong os::current_thread_cpu_time() { 5346 if (os::Linux::supports_fast_thread_cpu_time()) { 5347 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5348 } else { 5349 // return user + sys since the cost is the same 5350 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5351 } 5352 } 5353 5354 jlong os::thread_cpu_time(Thread* thread) { 5355 // consistent with what current_thread_cpu_time() returns 5356 if (os::Linux::supports_fast_thread_cpu_time()) { 5357 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5358 } else { 5359 return slow_thread_cpu_time(thread, true /* user + sys */); 5360 } 5361 } 5362 5363 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5364 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5365 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5366 } else { 5367 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5368 } 5369 } 5370 5371 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5372 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5373 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5374 } else { 5375 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5376 } 5377 } 5378 5379 // 5380 // -1 on error. 5381 // 5382 5383 PRAGMA_DIAG_PUSH 5384 PRAGMA_FORMAT_NONLITERAL_IGNORED 5385 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5386 static bool proc_task_unchecked = true; 5387 static const char *proc_stat_path = "/proc/%d/stat"; 5388 pid_t tid = thread->osthread()->thread_id(); 5389 char *s; 5390 char stat[2048]; 5391 int statlen; 5392 char proc_name[64]; 5393 int count; 5394 long sys_time, user_time; 5395 char cdummy; 5396 int idummy; 5397 long ldummy; 5398 FILE *fp; 5399 5400 // The /proc/<tid>/stat aggregates per-process usage on 5401 // new Linux kernels 2.6+ where NPTL is supported. 5402 // The /proc/self/task/<tid>/stat still has the per-thread usage. 5403 // See bug 6328462. 5404 // There possibly can be cases where there is no directory 5405 // /proc/self/task, so we check its availability. 5406 if (proc_task_unchecked && os::Linux::is_NPTL()) { 5407 // This is executed only once 5408 proc_task_unchecked = false; 5409 fp = fopen("/proc/self/task", "r"); 5410 if (fp != NULL) { 5411 proc_stat_path = "/proc/self/task/%d/stat"; 5412 fclose(fp); 5413 } 5414 } 5415 5416 sprintf(proc_name, proc_stat_path, tid); 5417 fp = fopen(proc_name, "r"); 5418 if ( fp == NULL ) return -1; 5419 statlen = fread(stat, 1, 2047, fp); 5420 stat[statlen] = '\0'; 5421 fclose(fp); 5422 5423 // Skip pid and the command string. Note that we could be dealing with 5424 // weird command names, e.g. user could decide to rename java launcher 5425 // to "java 1.4.2 :)", then the stat file would look like 5426 // 1234 (java 1.4.2 :)) R ... ... 5427 // We don't really need to know the command string, just find the last 5428 // occurrence of ")" and then start parsing from there. See bug 4726580. 5429 s = strrchr(stat, ')'); 5430 if (s == NULL ) return -1; 5431 5432 // Skip blank chars 5433 do s++; while (isspace(*s)); 5434 5435 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5436 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5437 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5438 &user_time, &sys_time); 5439 if ( count != 13 ) return -1; 5440 if (user_sys_cpu_time) { 5441 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5442 } else { 5443 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5444 } 5445 } 5446 PRAGMA_DIAG_POP 5447 5448 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5449 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5450 info_ptr->may_skip_backward = false; // elapsed time not wall time 5451 info_ptr->may_skip_forward = false; // elapsed time not wall time 5452 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5453 } 5454 5455 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5456 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5457 info_ptr->may_skip_backward = false; // elapsed time not wall time 5458 info_ptr->may_skip_forward = false; // elapsed time not wall time 5459 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5460 } 5461 5462 bool os::is_thread_cpu_time_supported() { 5463 return true; 5464 } 5465 5466 // System loadavg support. Returns -1 if load average cannot be obtained. 5467 // Linux doesn't yet have a (official) notion of processor sets, 5468 // so just return the system wide load average. 5469 int os::loadavg(double loadavg[], int nelem) { 5470 return ::getloadavg(loadavg, nelem); 5471 } 5472 5473 void os::pause() { 5474 char filename[MAX_PATH]; 5475 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5476 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 5477 } else { 5478 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5479 } 5480 5481 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5482 if (fd != -1) { 5483 struct stat buf; 5484 ::close(fd); 5485 while (::stat(filename, &buf) == 0) { 5486 (void)::poll(NULL, 0, 100); 5487 } 5488 } else { 5489 jio_fprintf(stderr, 5490 "Could not open pause file '%s', continuing immediately.\n", filename); 5491 } 5492 } 5493 5494 5495 // Refer to the comments in os_solaris.cpp park-unpark. 5496 // 5497 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 5498 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 5499 // For specifics regarding the bug see GLIBC BUGID 261237 : 5500 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 5501 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 5502 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 5503 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 5504 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 5505 // and monitorenter when we're using 1-0 locking. All those operations may result in 5506 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 5507 // of libpthread avoids the problem, but isn't practical. 5508 // 5509 // Possible remedies: 5510 // 5511 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 5512 // This is palliative and probabilistic, however. If the thread is preempted 5513 // between the call to compute_abstime() and pthread_cond_timedwait(), more 5514 // than the minimum period may have passed, and the abstime may be stale (in the 5515 // past) resultin in a hang. Using this technique reduces the odds of a hang 5516 // but the JVM is still vulnerable, particularly on heavily loaded systems. 5517 // 5518 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5519 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5520 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5521 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5522 // thread. 5523 // 5524 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5525 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5526 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5527 // This also works well. In fact it avoids kernel-level scalability impediments 5528 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 5529 // timers in a graceful fashion. 5530 // 5531 // 4. When the abstime value is in the past it appears that control returns 5532 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5533 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5534 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 5535 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5536 // It may be possible to avoid reinitialization by checking the return 5537 // value from pthread_cond_timedwait(). In addition to reinitializing the 5538 // condvar we must establish the invariant that cond_signal() is only called 5539 // within critical sections protected by the adjunct mutex. This prevents 5540 // cond_signal() from "seeing" a condvar that's in the midst of being 5541 // reinitialized or that is corrupt. Sadly, this invariant obviates the 5542 // desirable signal-after-unlock optimization that avoids futile context switching. 5543 // 5544 // I'm also concerned that some versions of NTPL might allocate an auxilliary 5545 // structure when a condvar is used or initialized. cond_destroy() would 5546 // release the helper structure. Our reinitialize-after-timedwait fix 5547 // put excessive stress on malloc/free and locks protecting the c-heap. 5548 // 5549 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5550 // It may be possible to refine (4) by checking the kernel and NTPL verisons 5551 // and only enabling the work-around for vulnerable environments. 5552 5553 // utility to compute the abstime argument to timedwait: 5554 // millis is the relative timeout time 5555 // abstime will be the absolute timeout time 5556 // TODO: replace compute_abstime() with unpackTime() 5557 5558 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5559 if (millis < 0) millis = 0; 5560 5561 jlong seconds = millis / 1000; 5562 millis %= 1000; 5563 if (seconds > 50000000) { // see man cond_timedwait(3T) 5564 seconds = 50000000; 5565 } 5566 5567 if (os::Linux::supports_monotonic_clock()) { 5568 struct timespec now; 5569 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5570 assert_status(status == 0, status, "clock_gettime"); 5571 abstime->tv_sec = now.tv_sec + seconds; 5572 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5573 if (nanos >= NANOSECS_PER_SEC) { 5574 abstime->tv_sec += 1; 5575 nanos -= NANOSECS_PER_SEC; 5576 } 5577 abstime->tv_nsec = nanos; 5578 } else { 5579 struct timeval now; 5580 int status = gettimeofday(&now, NULL); 5581 assert(status == 0, "gettimeofday"); 5582 abstime->tv_sec = now.tv_sec + seconds; 5583 long usec = now.tv_usec + millis * 1000; 5584 if (usec >= 1000000) { 5585 abstime->tv_sec += 1; 5586 usec -= 1000000; 5587 } 5588 abstime->tv_nsec = usec * 1000; 5589 } 5590 return abstime; 5591 } 5592 5593 5594 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 5595 // Conceptually TryPark() should be equivalent to park(0). 5596 5597 int os::PlatformEvent::TryPark() { 5598 for (;;) { 5599 const int v = _Event ; 5600 guarantee ((v == 0) || (v == 1), "invariant") ; 5601 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 5602 } 5603 } 5604 5605 void os::PlatformEvent::park() { // AKA "down()" 5606 // Invariant: Only the thread associated with the Event/PlatformEvent 5607 // may call park(). 5608 // TODO: assert that _Assoc != NULL or _Assoc == Self 5609 int v ; 5610 for (;;) { 5611 v = _Event ; 5612 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5613 } 5614 guarantee (v >= 0, "invariant") ; 5615 if (v == 0) { 5616 // Do this the hard way by blocking ... 5617 int status = pthread_mutex_lock(_mutex); 5618 assert_status(status == 0, status, "mutex_lock"); 5619 guarantee (_nParked == 0, "invariant") ; 5620 ++ _nParked ; 5621 while (_Event < 0) { 5622 status = pthread_cond_wait(_cond, _mutex); 5623 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5624 // Treat this the same as if the wait was interrupted 5625 if (status == ETIME) { status = EINTR; } 5626 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5627 } 5628 -- _nParked ; 5629 5630 _Event = 0 ; 5631 status = pthread_mutex_unlock(_mutex); 5632 assert_status(status == 0, status, "mutex_unlock"); 5633 // Paranoia to ensure our locked and lock-free paths interact 5634 // correctly with each other. 5635 OrderAccess::fence(); 5636 } 5637 guarantee (_Event >= 0, "invariant") ; 5638 } 5639 5640 int os::PlatformEvent::park(jlong millis) { 5641 guarantee (_nParked == 0, "invariant") ; 5642 5643 int v ; 5644 for (;;) { 5645 v = _Event ; 5646 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5647 } 5648 guarantee (v >= 0, "invariant") ; 5649 if (v != 0) return OS_OK ; 5650 5651 // We do this the hard way, by blocking the thread. 5652 // Consider enforcing a minimum timeout value. 5653 struct timespec abst; 5654 compute_abstime(&abst, millis); 5655 5656 int ret = OS_TIMEOUT; 5657 int status = pthread_mutex_lock(_mutex); 5658 assert_status(status == 0, status, "mutex_lock"); 5659 guarantee (_nParked == 0, "invariant") ; 5660 ++_nParked ; 5661 5662 // Object.wait(timo) will return because of 5663 // (a) notification 5664 // (b) timeout 5665 // (c) thread.interrupt 5666 // 5667 // Thread.interrupt and object.notify{All} both call Event::set. 5668 // That is, we treat thread.interrupt as a special case of notification. 5669 // The underlying Solaris implementation, cond_timedwait, admits 5670 // spurious/premature wakeups, but the JLS/JVM spec prevents the 5671 // JVM from making those visible to Java code. As such, we must 5672 // filter out spurious wakeups. We assume all ETIME returns are valid. 5673 // 5674 // TODO: properly differentiate simultaneous notify+interrupt. 5675 // In that case, we should propagate the notify to another waiter. 5676 5677 while (_Event < 0) { 5678 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5679 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5680 pthread_cond_destroy (_cond); 5681 pthread_cond_init (_cond, os::Linux::condAttr()) ; 5682 } 5683 assert_status(status == 0 || status == EINTR || 5684 status == ETIME || status == ETIMEDOUT, 5685 status, "cond_timedwait"); 5686 if (!FilterSpuriousWakeups) break ; // previous semantics 5687 if (status == ETIME || status == ETIMEDOUT) break ; 5688 // We consume and ignore EINTR and spurious wakeups. 5689 } 5690 --_nParked ; 5691 if (_Event >= 0) { 5692 ret = OS_OK; 5693 } 5694 _Event = 0 ; 5695 status = pthread_mutex_unlock(_mutex); 5696 assert_status(status == 0, status, "mutex_unlock"); 5697 assert (_nParked == 0, "invariant") ; 5698 // Paranoia to ensure our locked and lock-free paths interact 5699 // correctly with each other. 5700 OrderAccess::fence(); 5701 return ret; 5702 } 5703 5704 void os::PlatformEvent::unpark() { 5705 // Transitions for _Event: 5706 // 0 :=> 1 5707 // 1 :=> 1 5708 // -1 :=> either 0 or 1; must signal target thread 5709 // That is, we can safely transition _Event from -1 to either 5710 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back 5711 // unpark() calls. 5712 // See also: "Semaphores in Plan 9" by Mullender & Cox 5713 // 5714 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5715 // that it will take two back-to-back park() calls for the owning 5716 // thread to block. This has the benefit of forcing a spurious return 5717 // from the first park() call after an unpark() call which will help 5718 // shake out uses of park() and unpark() without condition variables. 5719 5720 if (Atomic::xchg(1, &_Event) >= 0) return; 5721 5722 // Wait for the thread associated with the event to vacate 5723 int status = pthread_mutex_lock(_mutex); 5724 assert_status(status == 0, status, "mutex_lock"); 5725 int AnyWaiters = _nParked; 5726 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5727 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5728 AnyWaiters = 0; 5729 pthread_cond_signal(_cond); 5730 } 5731 status = pthread_mutex_unlock(_mutex); 5732 assert_status(status == 0, status, "mutex_unlock"); 5733 if (AnyWaiters != 0) { 5734 status = pthread_cond_signal(_cond); 5735 assert_status(status == 0, status, "cond_signal"); 5736 } 5737 5738 // Note that we signal() _after dropping the lock for "immortal" Events. 5739 // This is safe and avoids a common class of futile wakeups. In rare 5740 // circumstances this can cause a thread to return prematurely from 5741 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5742 // simply re-test the condition and re-park itself. 5743 } 5744 5745 5746 // JSR166 5747 // ------------------------------------------------------- 5748 5749 /* 5750 * The solaris and linux implementations of park/unpark are fairly 5751 * conservative for now, but can be improved. They currently use a 5752 * mutex/condvar pair, plus a a count. 5753 * Park decrements count if > 0, else does a condvar wait. Unpark 5754 * sets count to 1 and signals condvar. Only one thread ever waits 5755 * on the condvar. Contention seen when trying to park implies that someone 5756 * is unparking you, so don't wait. And spurious returns are fine, so there 5757 * is no need to track notifications. 5758 */ 5759 5760 /* 5761 * This code is common to linux and solaris and will be moved to a 5762 * common place in dolphin. 5763 * 5764 * The passed in time value is either a relative time in nanoseconds 5765 * or an absolute time in milliseconds. Either way it has to be unpacked 5766 * into suitable seconds and nanoseconds components and stored in the 5767 * given timespec structure. 5768 * Given time is a 64-bit value and the time_t used in the timespec is only 5769 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5770 * overflow if times way in the future are given. Further on Solaris versions 5771 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5772 * number of seconds, in abstime, is less than current_time + 100,000,000. 5773 * As it will be 28 years before "now + 100000000" will overflow we can 5774 * ignore overflow and just impose a hard-limit on seconds using the value 5775 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5776 * years from "now". 5777 */ 5778 5779 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5780 assert (time > 0, "convertTime"); 5781 time_t max_secs = 0; 5782 5783 if (!os::Linux::supports_monotonic_clock() || isAbsolute) { 5784 struct timeval now; 5785 int status = gettimeofday(&now, NULL); 5786 assert(status == 0, "gettimeofday"); 5787 5788 max_secs = now.tv_sec + MAX_SECS; 5789 5790 if (isAbsolute) { 5791 jlong secs = time / 1000; 5792 if (secs > max_secs) { 5793 absTime->tv_sec = max_secs; 5794 } else { 5795 absTime->tv_sec = secs; 5796 } 5797 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5798 } else { 5799 jlong secs = time / NANOSECS_PER_SEC; 5800 if (secs >= MAX_SECS) { 5801 absTime->tv_sec = max_secs; 5802 absTime->tv_nsec = 0; 5803 } else { 5804 absTime->tv_sec = now.tv_sec + secs; 5805 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5806 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5807 absTime->tv_nsec -= NANOSECS_PER_SEC; 5808 ++absTime->tv_sec; // note: this must be <= max_secs 5809 } 5810 } 5811 } 5812 } else { 5813 // must be relative using monotonic clock 5814 struct timespec now; 5815 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5816 assert_status(status == 0, status, "clock_gettime"); 5817 max_secs = now.tv_sec + MAX_SECS; 5818 jlong secs = time / NANOSECS_PER_SEC; 5819 if (secs >= MAX_SECS) { 5820 absTime->tv_sec = max_secs; 5821 absTime->tv_nsec = 0; 5822 } else { 5823 absTime->tv_sec = now.tv_sec + secs; 5824 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5825 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5826 absTime->tv_nsec -= NANOSECS_PER_SEC; 5827 ++absTime->tv_sec; // note: this must be <= max_secs 5828 } 5829 } 5830 } 5831 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5832 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5833 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5834 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5835 } 5836 5837 void Parker::park(bool isAbsolute, jlong time) { 5838 // Ideally we'd do something useful while spinning, such 5839 // as calling unpackTime(). 5840 5841 // Optional fast-path check: 5842 // Return immediately if a permit is available. 5843 // We depend on Atomic::xchg() having full barrier semantics 5844 // since we are doing a lock-free update to _counter. 5845 if (Atomic::xchg(0, &_counter) > 0) return; 5846 5847 Thread* thread = Thread::current(); 5848 assert(thread->is_Java_thread(), "Must be JavaThread"); 5849 JavaThread *jt = (JavaThread *)thread; 5850 5851 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5852 // Check interrupt before trying to wait 5853 if (Thread::is_interrupted(thread, false)) { 5854 return; 5855 } 5856 5857 // Next, demultiplex/decode time arguments 5858 timespec absTime; 5859 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5860 return; 5861 } 5862 if (time > 0) { 5863 unpackTime(&absTime, isAbsolute, time); 5864 } 5865 5866 5867 // Enter safepoint region 5868 // Beware of deadlocks such as 6317397. 5869 // The per-thread Parker:: mutex is a classic leaf-lock. 5870 // In particular a thread must never block on the Threads_lock while 5871 // holding the Parker:: mutex. If safepoints are pending both the 5872 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5873 ThreadBlockInVM tbivm(jt); 5874 5875 // Don't wait if cannot get lock since interference arises from 5876 // unblocking. Also. check interrupt before trying wait 5877 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5878 return; 5879 } 5880 5881 int status ; 5882 if (_counter > 0) { // no wait needed 5883 _counter = 0; 5884 status = pthread_mutex_unlock(_mutex); 5885 assert (status == 0, "invariant") ; 5886 // Paranoia to ensure our locked and lock-free paths interact 5887 // correctly with each other and Java-level accesses. 5888 OrderAccess::fence(); 5889 return; 5890 } 5891 5892 #ifdef ASSERT 5893 // Don't catch signals while blocked; let the running threads have the signals. 5894 // (This allows a debugger to break into the running thread.) 5895 sigset_t oldsigs; 5896 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5897 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5898 #endif 5899 5900 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5901 jt->set_suspend_equivalent(); 5902 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5903 5904 assert(_cur_index == -1, "invariant"); 5905 if (time == 0) { 5906 _cur_index = REL_INDEX; // arbitrary choice when not timed 5907 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ; 5908 } else { 5909 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5910 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ; 5911 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5912 pthread_cond_destroy (&_cond[_cur_index]) ; 5913 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr()); 5914 } 5915 } 5916 _cur_index = -1; 5917 assert_status(status == 0 || status == EINTR || 5918 status == ETIME || status == ETIMEDOUT, 5919 status, "cond_timedwait"); 5920 5921 #ifdef ASSERT 5922 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5923 #endif 5924 5925 _counter = 0 ; 5926 status = pthread_mutex_unlock(_mutex) ; 5927 assert_status(status == 0, status, "invariant") ; 5928 // Paranoia to ensure our locked and lock-free paths interact 5929 // correctly with each other and Java-level accesses. 5930 OrderAccess::fence(); 5931 5932 // If externally suspended while waiting, re-suspend 5933 if (jt->handle_special_suspend_equivalent_condition()) { 5934 jt->java_suspend_self(); 5935 } 5936 } 5937 5938 void Parker::unpark() { 5939 int s, status ; 5940 status = pthread_mutex_lock(_mutex); 5941 assert (status == 0, "invariant") ; 5942 s = _counter; 5943 _counter = 1; 5944 if (s < 1) { 5945 // thread might be parked 5946 if (_cur_index != -1) { 5947 // thread is definitely parked 5948 if (WorkAroundNPTLTimedWaitHang) { 5949 status = pthread_cond_signal (&_cond[_cur_index]); 5950 assert (status == 0, "invariant"); 5951 status = pthread_mutex_unlock(_mutex); 5952 assert (status == 0, "invariant"); 5953 } else { 5954 status = pthread_mutex_unlock(_mutex); 5955 assert (status == 0, "invariant"); 5956 status = pthread_cond_signal (&_cond[_cur_index]); 5957 assert (status == 0, "invariant"); 5958 } 5959 } else { 5960 pthread_mutex_unlock(_mutex); 5961 assert (status == 0, "invariant") ; 5962 } 5963 } else { 5964 pthread_mutex_unlock(_mutex); 5965 assert (status == 0, "invariant") ; 5966 } 5967 } 5968 5969 5970 extern char** environ; 5971 5972 #ifndef __NR_fork 5973 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5974 #endif 5975 5976 #ifndef __NR_execve 5977 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5978 #endif 5979 5980 // Run the specified command in a separate process. Return its exit value, 5981 // or -1 on failure (e.g. can't fork a new process). 5982 // Unlike system(), this function can be called from signal handler. It 5983 // doesn't block SIGINT et al. 5984 int os::fork_and_exec(char* cmd) { 5985 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5986 5987 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5988 // pthread_atfork handlers and reset pthread library. All we need is a 5989 // separate process to execve. Make a direct syscall to fork process. 5990 // On IA64 there's no fork syscall, we have to use fork() and hope for 5991 // the best... 5992 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5993 IA64_ONLY(fork();) 5994 5995 if (pid < 0) { 5996 // fork failed 5997 return -1; 5998 5999 } else if (pid == 0) { 6000 // child process 6001 6002 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 6003 // first to kill every thread on the thread list. Because this list is 6004 // not reset by fork() (see notes above), execve() will instead kill 6005 // every thread in the parent process. We know this is the only thread 6006 // in the new process, so make a system call directly. 6007 // IA64 should use normal execve() from glibc to match the glibc fork() 6008 // above. 6009 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 6010 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 6011 6012 // execve failed 6013 _exit(-1); 6014 6015 } else { 6016 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 6017 // care about the actual exit code, for now. 6018 6019 int status; 6020 6021 // Wait for the child process to exit. This returns immediately if 6022 // the child has already exited. */ 6023 while (waitpid(pid, &status, 0) < 0) { 6024 switch (errno) { 6025 case ECHILD: return 0; 6026 case EINTR: break; 6027 default: return -1; 6028 } 6029 } 6030 6031 if (WIFEXITED(status)) { 6032 // The child exited normally; get its exit code. 6033 return WEXITSTATUS(status); 6034 } else if (WIFSIGNALED(status)) { 6035 // The child exited because of a signal 6036 // The best value to return is 0x80 + signal number, 6037 // because that is what all Unix shells do, and because 6038 // it allows callers to distinguish between process exit and 6039 // process death by signal. 6040 return 0x80 + WTERMSIG(status); 6041 } else { 6042 // Unknown exit code; pass it through 6043 return status; 6044 } 6045 } 6046 } 6047 6048 // is_headless_jre() 6049 // 6050 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 6051 // in order to report if we are running in a headless jre 6052 // 6053 // Since JDK8 xawt/libmawt.so was moved into the same directory 6054 // as libawt.so, and renamed libawt_xawt.so 6055 // 6056 bool os::is_headless_jre() { 6057 struct stat statbuf; 6058 char buf[MAXPATHLEN]; 6059 char libmawtpath[MAXPATHLEN]; 6060 const char *xawtstr = "/xawt/libmawt.so"; 6061 const char *new_xawtstr = "/libawt_xawt.so"; 6062 char *p; 6063 6064 // Get path to libjvm.so 6065 os::jvm_path(buf, sizeof(buf)); 6066 6067 // Get rid of libjvm.so 6068 p = strrchr(buf, '/'); 6069 if (p == NULL) return false; 6070 else *p = '\0'; 6071 6072 // Get rid of client or server 6073 p = strrchr(buf, '/'); 6074 if (p == NULL) return false; 6075 else *p = '\0'; 6076 6077 // check xawt/libmawt.so 6078 strcpy(libmawtpath, buf); 6079 strcat(libmawtpath, xawtstr); 6080 if (::stat(libmawtpath, &statbuf) == 0) return false; 6081 6082 // check libawt_xawt.so 6083 strcpy(libmawtpath, buf); 6084 strcat(libmawtpath, new_xawtstr); 6085 if (::stat(libmawtpath, &statbuf) == 0) return false; 6086 6087 return true; 6088 } 6089 6090 // Get the default path to the core file 6091 // Returns the length of the string 6092 int os::get_core_path(char* buffer, size_t bufferSize) { 6093 const char* p = get_current_directory(buffer, bufferSize); 6094 6095 if (p == NULL) { 6096 assert(p != NULL, "failed to get current directory"); 6097 return 0; 6098 } 6099 6100 return strlen(buffer); 6101 } 6102 6103 #ifdef JAVASE_EMBEDDED 6104 // 6105 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory. 6106 // 6107 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL; 6108 6109 // ctor 6110 // 6111 MemNotifyThread::MemNotifyThread(int fd): Thread() { 6112 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread"); 6113 _fd = fd; 6114 6115 if (os::create_thread(this, os::os_thread)) { 6116 _memnotify_thread = this; 6117 os::set_priority(this, NearMaxPriority); 6118 os::start_thread(this); 6119 } 6120 } 6121 6122 // Where all the work gets done 6123 // 6124 void MemNotifyThread::run() { 6125 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread"); 6126 6127 // Set up the select arguments 6128 fd_set rfds; 6129 if (_fd != -1) { 6130 FD_ZERO(&rfds); 6131 FD_SET(_fd, &rfds); 6132 } 6133 6134 // Now wait for the mem_notify device to wake up 6135 while (1) { 6136 // Wait for the mem_notify device to signal us.. 6137 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL); 6138 if (rc == -1) { 6139 perror("select!\n"); 6140 break; 6141 } else if (rc) { 6142 //ssize_t free_before = os::available_memory(); 6143 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024); 6144 6145 // The kernel is telling us there is not much memory left... 6146 // try to do something about that 6147 6148 // If we are not already in a GC, try one. 6149 if (!Universe::heap()->is_gc_active()) { 6150 Universe::heap()->collect(GCCause::_allocation_failure); 6151 6152 //ssize_t free_after = os::available_memory(); 6153 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024); 6154 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024); 6155 } 6156 // We might want to do something like the following if we find the GC's are not helping... 6157 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true); 6158 } 6159 } 6160 } 6161 6162 // 6163 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it. 6164 // 6165 void MemNotifyThread::start() { 6166 int fd; 6167 fd = open ("/dev/mem_notify", O_RDONLY, 0); 6168 if (fd < 0) { 6169 return; 6170 } 6171 6172 if (memnotify_thread() == NULL) { 6173 new MemNotifyThread(fd); 6174 } 6175 } 6176 6177 #endif // JAVASE_EMBEDDED 6178 6179 6180 /////////////// Unit tests /////////////// 6181 6182 #ifndef PRODUCT 6183 6184 #define test_log(...) \ 6185 do {\ 6186 if (VerboseInternalVMTests) { \ 6187 tty->print_cr(__VA_ARGS__); \ 6188 tty->flush(); \ 6189 }\ 6190 } while (false) 6191 6192 class TestReserveMemorySpecial : AllStatic { 6193 public: 6194 static void small_page_write(void* addr, size_t size) { 6195 size_t page_size = os::vm_page_size(); 6196 6197 char* end = (char*)addr + size; 6198 for (char* p = (char*)addr; p < end; p += page_size) { 6199 *p = 1; 6200 } 6201 } 6202 6203 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6204 if (!UseHugeTLBFS) { 6205 return; 6206 } 6207 6208 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6209 6210 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6211 6212 if (addr != NULL) { 6213 small_page_write(addr, size); 6214 6215 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6216 } 6217 } 6218 6219 static void test_reserve_memory_special_huge_tlbfs_only() { 6220 if (!UseHugeTLBFS) { 6221 return; 6222 } 6223 6224 size_t lp = os::large_page_size(); 6225 6226 for (size_t size = lp; size <= lp * 10; size += lp) { 6227 test_reserve_memory_special_huge_tlbfs_only(size); 6228 } 6229 } 6230 6231 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) { 6232 if (!UseHugeTLBFS) { 6233 return; 6234 } 6235 6236 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")", 6237 size, alignment); 6238 6239 assert(size >= os::large_page_size(), "Incorrect input to test"); 6240 6241 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6242 6243 if (addr != NULL) { 6244 small_page_write(addr, size); 6245 6246 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6247 } 6248 } 6249 6250 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) { 6251 size_t lp = os::large_page_size(); 6252 size_t ag = os::vm_allocation_granularity(); 6253 6254 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6255 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment); 6256 } 6257 } 6258 6259 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6260 size_t lp = os::large_page_size(); 6261 size_t ag = os::vm_allocation_granularity(); 6262 6263 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp); 6264 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag); 6265 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2); 6266 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2); 6267 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag); 6268 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag); 6269 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2); 6270 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10); 6271 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2); 6272 } 6273 6274 static void test_reserve_memory_special_huge_tlbfs() { 6275 if (!UseHugeTLBFS) { 6276 return; 6277 } 6278 6279 test_reserve_memory_special_huge_tlbfs_only(); 6280 test_reserve_memory_special_huge_tlbfs_mixed(); 6281 } 6282 6283 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6284 if (!UseSHM) { 6285 return; 6286 } 6287 6288 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6289 6290 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6291 6292 if (addr != NULL) { 6293 assert(is_ptr_aligned(addr, alignment), "Check"); 6294 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6295 6296 small_page_write(addr, size); 6297 6298 os::Linux::release_memory_special_shm(addr, size); 6299 } 6300 } 6301 6302 static void test_reserve_memory_special_shm() { 6303 size_t lp = os::large_page_size(); 6304 size_t ag = os::vm_allocation_granularity(); 6305 6306 for (size_t size = ag; size < lp * 3; size += ag) { 6307 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6308 test_reserve_memory_special_shm(size, alignment); 6309 } 6310 } 6311 } 6312 6313 static void test() { 6314 test_reserve_memory_special_huge_tlbfs(); 6315 test_reserve_memory_special_shm(); 6316 } 6317 }; 6318 6319 void TestReserveMemorySpecial_test() { 6320 TestReserveMemorySpecial::test(); 6321 } 6322 6323 #endif