1 /*
2 * Copyright (c) 1999, 2011, 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 "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/filemap.hpp"
36 #include "mutex_linux.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "os_share_linux.hpp"
39 #include "prims/jniFastGetField.hpp"
40 #include "prims/jvm.h"
41 #include "prims/jvm_misc.hpp"
42 #include "runtime/arguments.hpp"
43 #include "runtime/extendedPC.hpp"
44 #include "runtime/globals.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/mutexLocker.hpp"
49 #include "runtime/objectMonitor.hpp"
50 #include "runtime/osThread.hpp"
51 #include "runtime/perfMemory.hpp"
52 #include "runtime/sharedRuntime.hpp"
53 #include "runtime/statSampler.hpp"
54 #include "runtime/stubRoutines.hpp"
55 #include "runtime/threadCritical.hpp"
56 #include "runtime/timer.hpp"
57 #include "services/attachListener.hpp"
58 #include "services/runtimeService.hpp"
59 #include "thread_linux.inline.hpp"
60 #include "utilities/decoder.hpp"
61 #include "utilities/defaultStream.hpp"
62 #include "utilities/events.hpp"
63 #include "utilities/growableArray.hpp"
64 #include "utilities/vmError.hpp"
65 #ifdef TARGET_ARCH_x86
66 # include "assembler_x86.inline.hpp"
67 # include "nativeInst_x86.hpp"
68 #endif
69 #ifdef TARGET_ARCH_sparc
70 # include "assembler_sparc.inline.hpp"
71 # include "nativeInst_sparc.hpp"
72 #endif
73 #ifdef TARGET_ARCH_zero
74 # include "assembler_zero.inline.hpp"
75 # include "nativeInst_zero.hpp"
76 #endif
77 #ifdef TARGET_ARCH_arm
78 # include "assembler_arm.inline.hpp"
79 # include "nativeInst_arm.hpp"
80 #endif
81 #ifdef TARGET_ARCH_ppc
82 # include "assembler_ppc.inline.hpp"
83 # include "nativeInst_ppc.hpp"
84 #endif
85 #ifdef COMPILER1
86 #include "c1/c1_Runtime1.hpp"
87 #endif
88 #ifdef COMPILER2
89 #include "opto/runtime.hpp"
90 #endif
91
92 // put OS-includes here
93 # include <sys/types.h>
94 # include <sys/mman.h>
95 # include <sys/stat.h>
96 # include <sys/select.h>
97 # include <pthread.h>
98 # include <signal.h>
99 # include <errno.h>
100 # include <dlfcn.h>
101 # include <stdio.h>
102 # include <unistd.h>
103 # include <sys/resource.h>
104 # include <pthread.h>
105 # include <sys/stat.h>
106 # include <sys/time.h>
107 # include <sys/times.h>
108 # include <sys/utsname.h>
109 # include <sys/socket.h>
110 # include <sys/wait.h>
111 # include <pwd.h>
112 # include <poll.h>
113 # include <semaphore.h>
114 # include <fcntl.h>
115 # include <string.h>
116 # include <syscall.h>
117 # include <sys/sysinfo.h>
118 # include <gnu/libc-version.h>
119 # include <sys/ipc.h>
120 # include <sys/shm.h>
121 # include <link.h>
122 # include <stdint.h>
123 # include <inttypes.h>
124 # include <sys/ioctl.h>
125
126 #define MAX_PATH (2 * K)
127
128 // for timer info max values which include all bits
129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
130
131 #define LARGEPAGES_BIT (1 << 6)
132 ////////////////////////////////////////////////////////////////////////////////
133 // global variables
134 julong os::Linux::_physical_memory = 0;
135
136 address os::Linux::_initial_thread_stack_bottom = NULL;
137 uintptr_t os::Linux::_initial_thread_stack_size = 0;
138
139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
141 Mutex* os::Linux::_createThread_lock = NULL;
142 pthread_t os::Linux::_main_thread;
143 int os::Linux::_page_size = -1;
144 bool os::Linux::_is_floating_stack = false;
145 bool os::Linux::_is_NPTL = false;
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 const char * os::Linux::_glibc_version = NULL;
148 const char * os::Linux::_libpthread_version = NULL;
149
150 static jlong initial_time_count=0;
151
152 static int clock_tics_per_sec = 100;
153
154 // For diagnostics to print a message once. see run_periodic_checks
155 static sigset_t check_signal_done;
156 static bool check_signals = true;;
157
158 static pid_t _initial_pid = 0;
159
160 /* Signal number used to suspend/resume a thread */
161
162 /* do not use any signal number less than SIGSEGV, see 4355769 */
163 static int SR_signum = SIGUSR2;
164 sigset_t SR_sigset;
165
166 /* Used to protect dlsym() calls */
167 static pthread_mutex_t dl_mutex;
168
169 #ifdef JAVASE_EMBEDDED
170 class MemNotifyThread: public Thread {
171 friend class VMStructs;
172 public:
173 virtual void run();
174
175 private:
176 static MemNotifyThread* _memnotify_thread;
177 int _fd;
178
179 public:
180
181 // Constructor
182 MemNotifyThread(int fd);
183
184 // Tester
185 bool is_memnotify_thread() const { return true; }
186
187 // Printing
188 char* name() const { return (char*)"Linux MemNotify Thread"; }
189
190 // Returns the single instance of the MemNotifyThread
191 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
192
193 // Create and start the single instance of MemNotifyThread
194 static void start();
195 };
196 #endif // JAVASE_EMBEDDED
197
198 // utility functions
199
200 static int SR_initialize();
201 static int SR_finalize();
202
203 julong os::available_memory() {
204 return Linux::available_memory();
205 }
206
207 julong os::Linux::available_memory() {
208 // values in struct sysinfo are "unsigned long"
209 struct sysinfo si;
210 sysinfo(&si);
211
212 return (julong)si.freeram * si.mem_unit;
213 }
214
215 julong os::physical_memory() {
216 return Linux::physical_memory();
217 }
218
219 julong os::allocatable_physical_memory(julong size) {
220 #ifdef _LP64
221 return size;
222 #else
223 julong result = MIN2(size, (julong)3800*M);
224 if (!is_allocatable(result)) {
225 // See comments under solaris for alignment considerations
226 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
227 result = MIN2(size, reasonable_size);
228 }
229 return result;
230 #endif // _LP64
231 }
232
233 ////////////////////////////////////////////////////////////////////////////////
234 // environment support
235
236 bool os::getenv(const char* name, char* buf, int len) {
237 const char* val = ::getenv(name);
238 if (val != NULL && strlen(val) < (size_t)len) {
239 strcpy(buf, val);
240 return true;
241 }
242 if (len > 0) buf[0] = 0; // return a null string
243 return false;
244 }
245
246
247 // Return true if user is running as root.
248
249 bool os::have_special_privileges() {
250 static bool init = false;
251 static bool privileges = false;
252 if (!init) {
253 privileges = (getuid() != geteuid()) || (getgid() != getegid());
254 init = true;
255 }
256 return privileges;
257 }
258
259
260 #ifndef SYS_gettid
261 // i386: 224, ia64: 1105, amd64: 186, sparc 143
262 #ifdef __ia64__
263 #define SYS_gettid 1105
264 #elif __i386__
265 #define SYS_gettid 224
266 #elif __amd64__
267 #define SYS_gettid 186
268 #elif __sparc__
269 #define SYS_gettid 143
270 #else
271 #error define gettid for the arch
272 #endif
273 #endif
274
275 // Cpu architecture string
276 #if defined(ZERO)
277 static char cpu_arch[] = ZERO_LIBARCH;
278 #elif defined(IA64)
279 static char cpu_arch[] = "ia64";
280 #elif defined(IA32)
281 static char cpu_arch[] = "i386";
282 #elif defined(AMD64)
283 static char cpu_arch[] = "amd64";
284 #elif defined(ARM)
285 static char cpu_arch[] = "arm";
286 #elif defined(PPC)
287 static char cpu_arch[] = "ppc";
288 #elif defined(SPARC)
289 # ifdef _LP64
290 static char cpu_arch[] = "sparcv9";
291 # else
292 static char cpu_arch[] = "sparc";
293 # endif
294 #else
295 #error Add appropriate cpu_arch setting
296 #endif
297
298
299 // pid_t gettid()
300 //
301 // Returns the kernel thread id of the currently running thread. Kernel
302 // thread id is used to access /proc.
303 //
304 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
305 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
306 //
307 pid_t os::Linux::gettid() {
308 int rslt = syscall(SYS_gettid);
309 if (rslt == -1) {
310 // old kernel, no NPTL support
311 return getpid();
312 } else {
313 return (pid_t)rslt;
314 }
315 }
316
317 // Most versions of linux have a bug where the number of processors are
318 // determined by looking at the /proc file system. In a chroot environment,
319 // the system call returns 1. This causes the VM to act as if it is
320 // a single processor and elide locking (see is_MP() call).
321 static bool unsafe_chroot_detected = false;
322 static const char *unstable_chroot_error = "/proc file system not found.\n"
323 "Java may be unstable running multithreaded in a chroot "
324 "environment on Linux when /proc filesystem is not mounted.";
325
326 void os::Linux::initialize_system_info() {
327 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
328 if (processor_count() == 1) {
329 pid_t pid = os::Linux::gettid();
330 char fname[32];
331 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
332 FILE *fp = fopen(fname, "r");
333 if (fp == NULL) {
334 unsafe_chroot_detected = true;
335 } else {
336 fclose(fp);
337 }
338 }
339 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
340 assert(processor_count() > 0, "linux error");
341 }
342
343 void os::init_system_properties_values() {
344 // char arch[12];
345 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
346
347 // The next steps are taken in the product version:
348 //
349 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
350 // This library should be located at:
351 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
352 //
353 // If "/jre/lib/" appears at the right place in the path, then we
354 // assume libjvm[_g].so is installed in a JDK and we use this path.
355 //
356 // Otherwise exit with message: "Could not create the Java virtual machine."
357 //
358 // The following extra steps are taken in the debugging version:
359 //
360 // If "/jre/lib/" does NOT appear at the right place in the path
361 // instead of exit check for $JAVA_HOME environment variable.
362 //
363 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
364 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
365 // it looks like libjvm[_g].so is installed there
366 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
367 //
368 // Otherwise exit.
369 //
370 // Important note: if the location of libjvm.so changes this
371 // code needs to be changed accordingly.
372
373 // The next few definitions allow the code to be verbatim:
374 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
375 #define getenv(n) ::getenv(n)
376
377 /*
378 * See ld(1):
379 * The linker uses the following search paths to locate required
380 * shared libraries:
381 * 1: ...
382 * ...
383 * 7: The default directories, normally /lib and /usr/lib.
384 */
385 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
386 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
387 #else
388 #define DEFAULT_LIBPATH "/lib:/usr/lib"
389 #endif
390
391 #define EXTENSIONS_DIR "/lib/ext"
392 #define ENDORSED_DIR "/lib/endorsed"
393 #define REG_DIR "/usr/java/packages"
394
395 {
396 /* sysclasspath, java_home, dll_dir */
397 {
398 char *home_path;
399 char *dll_path;
400 char *pslash;
401 char buf[MAXPATHLEN];
402 os::jvm_path(buf, sizeof(buf));
403
404 // Found the full path to libjvm.so.
405 // Now cut the path to <java_home>/jre if we can.
406 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
407 pslash = strrchr(buf, '/');
408 if (pslash != NULL)
409 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
410 dll_path = malloc(strlen(buf) + 1);
411 if (dll_path == NULL)
412 return;
413 strcpy(dll_path, buf);
414 Arguments::set_dll_dir(dll_path);
415
416 if (pslash != NULL) {
417 pslash = strrchr(buf, '/');
418 if (pslash != NULL) {
419 *pslash = '\0'; /* get rid of /<arch> */
420 pslash = strrchr(buf, '/');
421 if (pslash != NULL)
422 *pslash = '\0'; /* get rid of /lib */
423 }
424 }
425
426 home_path = malloc(strlen(buf) + 1);
427 if (home_path == NULL)
428 return;
429 strcpy(home_path, buf);
430 Arguments::set_java_home(home_path);
431
432 if (!set_boot_path('/', ':'))
433 return;
434 }
435
436 /*
437 * Where to look for native libraries
438 *
439 * Note: Due to a legacy implementation, most of the library path
440 * is set in the launcher. This was to accomodate linking restrictions
441 * on legacy Linux implementations (which are no longer supported).
442 * Eventually, all the library path setting will be done here.
443 *
444 * However, to prevent the proliferation of improperly built native
445 * libraries, the new path component /usr/java/packages is added here.
446 * Eventually, all the library path setting will be done here.
447 */
448 {
449 char *ld_library_path;
450
451 /*
452 * Construct the invariant part of ld_library_path. Note that the
453 * space for the colon and the trailing null are provided by the
454 * nulls included by the sizeof operator (so actually we allocate
455 * a byte more than necessary).
456 */
457 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
458 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
459 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
460
461 /*
462 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
463 * should always exist (until the legacy problem cited above is
464 * addressed).
465 */
466 char *v = getenv("LD_LIBRARY_PATH");
467 if (v != NULL) {
468 char *t = ld_library_path;
469 /* That's +1 for the colon and +1 for the trailing '\0' */
470 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
471 sprintf(ld_library_path, "%s:%s", v, t);
472 }
473 Arguments::set_library_path(ld_library_path);
474 }
475
476 /*
477 * Extensions directories.
478 *
479 * Note that the space for the colon and the trailing null are provided
480 * by the nulls included by the sizeof operator (so actually one byte more
481 * than necessary is allocated).
482 */
483 {
484 char *buf = malloc(strlen(Arguments::get_java_home()) +
485 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
486 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
487 Arguments::get_java_home());
488 Arguments::set_ext_dirs(buf);
489 }
490
491 /* Endorsed standards default directory. */
492 {
493 char * buf;
494 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
495 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
496 Arguments::set_endorsed_dirs(buf);
497 }
498 }
499
500 #undef malloc
501 #undef getenv
502 #undef EXTENSIONS_DIR
503 #undef ENDORSED_DIR
504
505 // Done
506 return;
507 }
508
509 ////////////////////////////////////////////////////////////////////////////////
510 // breakpoint support
511
512 void os::breakpoint() {
513 BREAKPOINT;
514 }
515
516 extern "C" void breakpoint() {
517 // use debugger to set breakpoint here
518 }
519
520 ////////////////////////////////////////////////////////////////////////////////
521 // signal support
522
523 debug_only(static bool signal_sets_initialized = false);
524 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
525
526 bool os::Linux::is_sig_ignored(int sig) {
527 struct sigaction oact;
528 sigaction(sig, (struct sigaction*)NULL, &oact);
529 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
530 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
531 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
532 return true;
533 else
534 return false;
535 }
536
537 void os::Linux::signal_sets_init() {
538 // Should also have an assertion stating we are still single-threaded.
539 assert(!signal_sets_initialized, "Already initialized");
540 // Fill in signals that are necessarily unblocked for all threads in
541 // the VM. Currently, we unblock the following signals:
542 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
543 // by -Xrs (=ReduceSignalUsage));
544 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
545 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
546 // the dispositions or masks wrt these signals.
547 // Programs embedding the VM that want to use the above signals for their
548 // own purposes must, at this time, use the "-Xrs" option to prevent
549 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
550 // (See bug 4345157, and other related bugs).
551 // In reality, though, unblocking these signals is really a nop, since
552 // these signals are not blocked by default.
553 sigemptyset(&unblocked_sigs);
554 sigemptyset(&allowdebug_blocked_sigs);
555 sigaddset(&unblocked_sigs, SIGILL);
556 sigaddset(&unblocked_sigs, SIGSEGV);
557 sigaddset(&unblocked_sigs, SIGBUS);
558 sigaddset(&unblocked_sigs, SIGFPE);
559 sigaddset(&unblocked_sigs, SR_signum);
560
561 if (!ReduceSignalUsage) {
562 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
563 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
564 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
565 }
566 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
567 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
568 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
569 }
570 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
571 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
572 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
573 }
574 }
575 // Fill in signals that are blocked by all but the VM thread.
576 sigemptyset(&vm_sigs);
577 if (!ReduceSignalUsage)
578 sigaddset(&vm_sigs, BREAK_SIGNAL);
579 debug_only(signal_sets_initialized = true);
580
581 }
582
583 // These are signals that are unblocked while a thread is running Java.
584 // (For some reason, they get blocked by default.)
585 sigset_t* os::Linux::unblocked_signals() {
586 assert(signal_sets_initialized, "Not initialized");
587 return &unblocked_sigs;
588 }
589
590 // These are the signals that are blocked while a (non-VM) thread is
591 // running Java. Only the VM thread handles these signals.
592 sigset_t* os::Linux::vm_signals() {
593 assert(signal_sets_initialized, "Not initialized");
594 return &vm_sigs;
595 }
596
597 // These are signals that are blocked during cond_wait to allow debugger in
598 sigset_t* os::Linux::allowdebug_blocked_signals() {
599 assert(signal_sets_initialized, "Not initialized");
600 return &allowdebug_blocked_sigs;
601 }
602
603 void os::Linux::hotspot_sigmask(Thread* thread) {
604
605 //Save caller's signal mask before setting VM signal mask
606 sigset_t caller_sigmask;
607 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
608
609 OSThread* osthread = thread->osthread();
610 osthread->set_caller_sigmask(caller_sigmask);
611
612 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
613
614 if (!ReduceSignalUsage) {
615 if (thread->is_VM_thread()) {
616 // Only the VM thread handles BREAK_SIGNAL ...
617 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
618 } else {
619 // ... all other threads block BREAK_SIGNAL
620 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
621 }
622 }
623 }
624
625 //////////////////////////////////////////////////////////////////////////////
626 // detecting pthread library
627
628 void os::Linux::libpthread_init() {
629 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
630 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
631 // generic name for earlier versions.
632 // Define macros here so we can build HotSpot on old systems.
633 # ifndef _CS_GNU_LIBC_VERSION
634 # define _CS_GNU_LIBC_VERSION 2
635 # endif
636 # ifndef _CS_GNU_LIBPTHREAD_VERSION
637 # define _CS_GNU_LIBPTHREAD_VERSION 3
638 # endif
639
640 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
641 if (n > 0) {
642 char *str = (char *)malloc(n);
643 confstr(_CS_GNU_LIBC_VERSION, str, n);
644 os::Linux::set_glibc_version(str);
645 } else {
646 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
647 static char _gnu_libc_version[32];
648 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
649 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
650 os::Linux::set_glibc_version(_gnu_libc_version);
651 }
652
653 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
654 if (n > 0) {
655 char *str = (char *)malloc(n);
656 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
657 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
658 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
659 // is the case. LinuxThreads has a hard limit on max number of threads.
660 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
661 // On the other hand, NPTL does not have such a limit, sysconf()
662 // will return -1 and errno is not changed. Check if it is really NPTL.
663 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
664 strstr(str, "NPTL") &&
665 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
666 free(str);
667 os::Linux::set_libpthread_version("linuxthreads");
668 } else {
669 os::Linux::set_libpthread_version(str);
670 }
671 } else {
672 // glibc before 2.3.2 only has LinuxThreads.
673 os::Linux::set_libpthread_version("linuxthreads");
674 }
675
676 if (strstr(libpthread_version(), "NPTL")) {
677 os::Linux::set_is_NPTL();
678 } else {
679 os::Linux::set_is_LinuxThreads();
680 }
681
682 // LinuxThreads have two flavors: floating-stack mode, which allows variable
683 // stack size; and fixed-stack mode. NPTL is always floating-stack.
684 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
685 os::Linux::set_is_floating_stack();
686 }
687 }
688
689 /////////////////////////////////////////////////////////////////////////////
690 // thread stack
691
692 // Force Linux kernel to expand current thread stack. If "bottom" is close
693 // to the stack guard, caller should block all signals.
694 //
695 // MAP_GROWSDOWN:
696 // A special mmap() flag that is used to implement thread stacks. It tells
697 // kernel that the memory region should extend downwards when needed. This
698 // allows early versions of LinuxThreads to only mmap the first few pages
699 // when creating a new thread. Linux kernel will automatically expand thread
700 // stack as needed (on page faults).
701 //
702 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
703 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
704 // region, it's hard to tell if the fault is due to a legitimate stack
705 // access or because of reading/writing non-exist memory (e.g. buffer
706 // overrun). As a rule, if the fault happens below current stack pointer,
707 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
708 // application (see Linux kernel fault.c).
709 //
710 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
711 // stack overflow detection.
712 //
713 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
714 // not use this flag. However, the stack of initial thread is not created
715 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
716 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
717 // and then attach the thread to JVM.
718 //
719 // To get around the problem and allow stack banging on Linux, we need to
720 // manually expand thread stack after receiving the SIGSEGV.
721 //
722 // There are two ways to expand thread stack to address "bottom", we used
723 // both of them in JVM before 1.5:
724 // 1. adjust stack pointer first so that it is below "bottom", and then
725 // touch "bottom"
726 // 2. mmap() the page in question
727 //
728 // Now alternate signal stack is gone, it's harder to use 2. For instance,
729 // if current sp is already near the lower end of page 101, and we need to
730 // call mmap() to map page 100, it is possible that part of the mmap() frame
731 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
732 // That will destroy the mmap() frame and cause VM to crash.
733 //
734 // The following code works by adjusting sp first, then accessing the "bottom"
735 // page to force a page fault. Linux kernel will then automatically expand the
736 // stack mapping.
737 //
738 // _expand_stack_to() assumes its frame size is less than page size, which
739 // should always be true if the function is not inlined.
740
741 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
742 #define NOINLINE
743 #else
744 #define NOINLINE __attribute__ ((noinline))
745 #endif
746
747 static void _expand_stack_to(address bottom) NOINLINE;
748
749 static void _expand_stack_to(address bottom) {
750 address sp;
751 size_t size;
752 volatile char *p;
753
754 // Adjust bottom to point to the largest address within the same page, it
755 // gives us a one-page buffer if alloca() allocates slightly more memory.
756 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
757 bottom += os::Linux::page_size() - 1;
758
759 // sp might be slightly above current stack pointer; if that's the case, we
760 // will alloca() a little more space than necessary, which is OK. Don't use
761 // os::current_stack_pointer(), as its result can be slightly below current
762 // stack pointer, causing us to not alloca enough to reach "bottom".
763 sp = (address)&sp;
764
765 if (sp > bottom) {
766 size = sp - bottom;
767 p = (volatile char *)alloca(size);
768 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
769 p[0] = '\0';
770 }
771 }
772
773 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
774 assert(t!=NULL, "just checking");
775 assert(t->osthread()->expanding_stack(), "expand should be set");
776 assert(t->stack_base() != NULL, "stack_base was not initialized");
777
778 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
779 sigset_t mask_all, old_sigset;
780 sigfillset(&mask_all);
781 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
782 _expand_stack_to(addr);
783 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
784 return true;
785 }
786 return false;
787 }
788
789 //////////////////////////////////////////////////////////////////////////////
790 // create new thread
791
792 static address highest_vm_reserved_address();
793
794 // check if it's safe to start a new thread
795 static bool _thread_safety_check(Thread* thread) {
796 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
797 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
798 // Heap is mmap'ed at lower end of memory space. Thread stacks are
799 // allocated (MAP_FIXED) from high address space. Every thread stack
800 // occupies a fixed size slot (usually 2Mbytes, but user can change
801 // it to other values if they rebuild LinuxThreads).
802 //
803 // Problem with MAP_FIXED is that mmap() can still succeed even part of
804 // the memory region has already been mmap'ed. That means if we have too
805 // many threads and/or very large heap, eventually thread stack will
806 // collide with heap.
807 //
808 // Here we try to prevent heap/stack collision by comparing current
809 // stack bottom with the highest address that has been mmap'ed by JVM
810 // plus a safety margin for memory maps created by native code.
811 //
812 // This feature can be disabled by setting ThreadSafetyMargin to 0
813 //
814 if (ThreadSafetyMargin > 0) {
815 address stack_bottom = os::current_stack_base() - os::current_stack_size();
816
817 // not safe if our stack extends below the safety margin
818 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
819 } else {
820 return true;
821 }
822 } else {
823 // Floating stack LinuxThreads or NPTL:
824 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
825 // there's not enough space left, pthread_create() will fail. If we come
826 // here, that means enough space has been reserved for stack.
827 return true;
828 }
829 }
830
831 // Thread start routine for all newly created threads
832 static void *java_start(Thread *thread) {
833 // Try to randomize the cache line index of hot stack frames.
834 // This helps when threads of the same stack traces evict each other's
835 // cache lines. The threads can be either from the same JVM instance, or
836 // from different JVM instances. The benefit is especially true for
837 // processors with hyperthreading technology.
838 static int counter = 0;
839 int pid = os::current_process_id();
840 alloca(((pid ^ counter++) & 7) * 128);
841
842 ThreadLocalStorage::set_thread(thread);
843
844 OSThread* osthread = thread->osthread();
845 Monitor* sync = osthread->startThread_lock();
846
847 // non floating stack LinuxThreads needs extra check, see above
848 if (!_thread_safety_check(thread)) {
849 // notify parent thread
850 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
851 osthread->set_state(ZOMBIE);
852 sync->notify_all();
853 return NULL;
854 }
855
856 // thread_id is kernel thread id (similar to Solaris LWP id)
857 osthread->set_thread_id(os::Linux::gettid());
858
859 if (UseNUMA) {
860 int lgrp_id = os::numa_get_group_id();
861 if (lgrp_id != -1) {
862 thread->set_lgrp_id(lgrp_id);
863 }
864 }
865 // initialize signal mask for this thread
866 os::Linux::hotspot_sigmask(thread);
867
868 // initialize floating point control register
869 os::Linux::init_thread_fpu_state();
870
871 // handshaking with parent thread
872 {
873 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
874
875 // notify parent thread
876 osthread->set_state(INITIALIZED);
877 sync->notify_all();
878
879 // wait until os::start_thread()
880 while (osthread->get_state() == INITIALIZED) {
881 sync->wait(Mutex::_no_safepoint_check_flag);
882 }
883 }
884
885 // call one more level start routine
886 thread->run();
887
888 return 0;
889 }
890
891 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
892 assert(thread->osthread() == NULL, "caller responsible");
893
894 // Allocate the OSThread object
895 OSThread* osthread = new OSThread(NULL, NULL);
896 if (osthread == NULL) {
897 return false;
898 }
899
900 // set the correct thread state
901 osthread->set_thread_type(thr_type);
902
903 // Initial state is ALLOCATED but not INITIALIZED
904 osthread->set_state(ALLOCATED);
905
906 thread->set_osthread(osthread);
907
908 // init thread attributes
909 pthread_attr_t attr;
910 pthread_attr_init(&attr);
911 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
912
913 // stack size
914 if (os::Linux::supports_variable_stack_size()) {
915 // calculate stack size if it's not specified by caller
916 if (stack_size == 0) {
917 stack_size = os::Linux::default_stack_size(thr_type);
918
919 switch (thr_type) {
920 case os::java_thread:
921 // Java threads use ThreadStackSize which default value can be
922 // changed with the flag -Xss
923 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
924 stack_size = JavaThread::stack_size_at_create();
925 break;
926 case os::compiler_thread:
927 if (CompilerThreadStackSize > 0) {
928 stack_size = (size_t)(CompilerThreadStackSize * K);
929 break;
930 } // else fall through:
931 // use VMThreadStackSize if CompilerThreadStackSize is not defined
932 case os::vm_thread:
933 case os::pgc_thread:
934 case os::cgc_thread:
935 case os::watcher_thread:
936 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
937 break;
938 }
939 }
940
941 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
942 pthread_attr_setstacksize(&attr, stack_size);
943 } else {
944 // let pthread_create() pick the default value.
945 }
946
947 // glibc guard page
948 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
949
950 ThreadState state;
951
952 {
953 // Serialize thread creation if we are running with fixed stack LinuxThreads
954 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
955 if (lock) {
956 os::Linux::createThread_lock()->lock_without_safepoint_check();
957 }
958
959 pthread_t tid;
960 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
961
962 pthread_attr_destroy(&attr);
963
964 if (ret != 0) {
965 if (PrintMiscellaneous && (Verbose || WizardMode)) {
966 perror("pthread_create()");
967 }
968 // Need to clean up stuff we've allocated so far
969 thread->set_osthread(NULL);
970 delete osthread;
971 if (lock) os::Linux::createThread_lock()->unlock();
972 return false;
973 }
974
975 // Store pthread info into the OSThread
976 osthread->set_pthread_id(tid);
977
978 // Wait until child thread is either initialized or aborted
979 {
980 Monitor* sync_with_child = osthread->startThread_lock();
981 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
982 while ((state = osthread->get_state()) == ALLOCATED) {
983 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
984 }
985 }
986
987 if (lock) {
988 os::Linux::createThread_lock()->unlock();
989 }
990 }
991
992 // Aborted due to thread limit being reached
993 if (state == ZOMBIE) {
994 thread->set_osthread(NULL);
995 delete osthread;
996 return false;
997 }
998
999 // The thread is returned suspended (in state INITIALIZED),
1000 // and is started higher up in the call chain
1001 assert(state == INITIALIZED, "race condition");
1002 return true;
1003 }
1004
1005 /////////////////////////////////////////////////////////////////////////////
1006 // attach existing thread
1007
1008 // bootstrap the main thread
1009 bool os::create_main_thread(JavaThread* thread) {
1010 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1011 return create_attached_thread(thread);
1012 }
1013
1014 bool os::create_attached_thread(JavaThread* thread) {
1015 #ifdef ASSERT
1016 thread->verify_not_published();
1017 #endif
1018
1019 // Allocate the OSThread object
1020 OSThread* osthread = new OSThread(NULL, NULL);
1021
1022 if (osthread == NULL) {
1023 return false;
1024 }
1025
1026 // Store pthread info into the OSThread
1027 osthread->set_thread_id(os::Linux::gettid());
1028 osthread->set_pthread_id(::pthread_self());
1029
1030 // initialize floating point control register
1031 os::Linux::init_thread_fpu_state();
1032
1033 // Initial thread state is RUNNABLE
1034 osthread->set_state(RUNNABLE);
1035
1036 thread->set_osthread(osthread);
1037
1038 if (UseNUMA) {
1039 int lgrp_id = os::numa_get_group_id();
1040 if (lgrp_id != -1) {
1041 thread->set_lgrp_id(lgrp_id);
1042 }
1043 }
1044
1045 if (os::Linux::is_initial_thread()) {
1046 // If current thread is initial thread, its stack is mapped on demand,
1047 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1048 // the entire stack region to avoid SEGV in stack banging.
1049 // It is also useful to get around the heap-stack-gap problem on SuSE
1050 // kernel (see 4821821 for details). We first expand stack to the top
1051 // of yellow zone, then enable stack yellow zone (order is significant,
1052 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1053 // is no gap between the last two virtual memory regions.
1054
1055 JavaThread *jt = (JavaThread *)thread;
1056 address addr = jt->stack_yellow_zone_base();
1057 assert(addr != NULL, "initialization problem?");
1058 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1059
1060 osthread->set_expanding_stack();
1061 os::Linux::manually_expand_stack(jt, addr);
1062 osthread->clear_expanding_stack();
1063 }
1064
1065 // initialize signal mask for this thread
1066 // and save the caller's signal mask
1067 os::Linux::hotspot_sigmask(thread);
1068
1069 return true;
1070 }
1071
1072 void os::pd_start_thread(Thread* thread) {
1073 OSThread * osthread = thread->osthread();
1074 assert(osthread->get_state() != INITIALIZED, "just checking");
1075 Monitor* sync_with_child = osthread->startThread_lock();
1076 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1077 sync_with_child->notify();
1078 }
1079
1080 // Free Linux resources related to the OSThread
1081 void os::free_thread(OSThread* osthread) {
1082 assert(osthread != NULL, "osthread not set");
1083
1084 if (Thread::current()->osthread() == osthread) {
1085 // Restore caller's signal mask
1086 sigset_t sigmask = osthread->caller_sigmask();
1087 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1088 }
1089
1090 delete osthread;
1091 }
1092
1093 //////////////////////////////////////////////////////////////////////////////
1094 // thread local storage
1095
1096 int os::allocate_thread_local_storage() {
1097 pthread_key_t key;
1098 int rslt = pthread_key_create(&key, NULL);
1099 assert(rslt == 0, "cannot allocate thread local storage");
1100 return (int)key;
1101 }
1102
1103 // Note: This is currently not used by VM, as we don't destroy TLS key
1104 // on VM exit.
1105 void os::free_thread_local_storage(int index) {
1106 int rslt = pthread_key_delete((pthread_key_t)index);
1107 assert(rslt == 0, "invalid index");
1108 }
1109
1110 void os::thread_local_storage_at_put(int index, void* value) {
1111 int rslt = pthread_setspecific((pthread_key_t)index, value);
1112 assert(rslt == 0, "pthread_setspecific failed");
1113 }
1114
1115 extern "C" Thread* get_thread() {
1116 return ThreadLocalStorage::thread();
1117 }
1118
1119 //////////////////////////////////////////////////////////////////////////////
1120 // initial thread
1121
1122 // Check if current thread is the initial thread, similar to Solaris thr_main.
1123 bool os::Linux::is_initial_thread(void) {
1124 char dummy;
1125 // If called before init complete, thread stack bottom will be null.
1126 // Can be called if fatal error occurs before initialization.
1127 if (initial_thread_stack_bottom() == NULL) return false;
1128 assert(initial_thread_stack_bottom() != NULL &&
1129 initial_thread_stack_size() != 0,
1130 "os::init did not locate initial thread's stack region");
1131 if ((address)&dummy >= initial_thread_stack_bottom() &&
1132 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1133 return true;
1134 else return false;
1135 }
1136
1137 // Find the virtual memory area that contains addr
1138 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1139 FILE *fp = fopen("/proc/self/maps", "r");
1140 if (fp) {
1141 address low, high;
1142 while (!feof(fp)) {
1143 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1144 if (low <= addr && addr < high) {
1145 if (vma_low) *vma_low = low;
1146 if (vma_high) *vma_high = high;
1147 fclose (fp);
1148 return true;
1149 }
1150 }
1151 for (;;) {
1152 int ch = fgetc(fp);
1153 if (ch == EOF || ch == (int)'\n') break;
1154 }
1155 }
1156 fclose(fp);
1157 }
1158 return false;
1159 }
1160
1161 // Locate initial thread stack. This special handling of initial thread stack
1162 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1163 // bogus value for initial thread.
1164 void os::Linux::capture_initial_stack(size_t max_size) {
1165 // stack size is the easy part, get it from RLIMIT_STACK
1166 size_t stack_size;
1167 struct rlimit rlim;
1168 getrlimit(RLIMIT_STACK, &rlim);
1169 stack_size = rlim.rlim_cur;
1170
1171 // 6308388: a bug in ld.so will relocate its own .data section to the
1172 // lower end of primordial stack; reduce ulimit -s value a little bit
1173 // so we won't install guard page on ld.so's data section.
1174 stack_size -= 2 * page_size();
1175
1176 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1177 // 7.1, in both cases we will get 2G in return value.
1178 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1179 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1180 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1181 // in case other parts in glibc still assumes 2M max stack size.
1182 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1183 #ifndef IA64
1184 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1185 #else
1186 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1187 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1188 #endif
1189
1190 // Try to figure out where the stack base (top) is. This is harder.
1191 //
1192 // When an application is started, glibc saves the initial stack pointer in
1193 // a global variable "__libc_stack_end", which is then used by system
1194 // libraries. __libc_stack_end should be pretty close to stack top. The
1195 // variable is available since the very early days. However, because it is
1196 // a private interface, it could disappear in the future.
1197 //
1198 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1199 // to __libc_stack_end, it is very close to stack top, but isn't the real
1200 // stack top. Note that /proc may not exist if VM is running as a chroot
1201 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1202 // /proc/<pid>/stat could change in the future (though unlikely).
1203 //
1204 // We try __libc_stack_end first. If that doesn't work, look for
1205 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1206 // as a hint, which should work well in most cases.
1207
1208 uintptr_t stack_start;
1209
1210 // try __libc_stack_end first
1211 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1212 if (p && *p) {
1213 stack_start = *p;
1214 } else {
1215 // see if we can get the start_stack field from /proc/self/stat
1216 FILE *fp;
1217 int pid;
1218 char state;
1219 int ppid;
1220 int pgrp;
1221 int session;
1222 int nr;
1223 int tpgrp;
1224 unsigned long flags;
1225 unsigned long minflt;
1226 unsigned long cminflt;
1227 unsigned long majflt;
1228 unsigned long cmajflt;
1229 unsigned long utime;
1230 unsigned long stime;
1231 long cutime;
1232 long cstime;
1233 long prio;
1234 long nice;
1235 long junk;
1236 long it_real;
1237 uintptr_t start;
1238 uintptr_t vsize;
1239 intptr_t rss;
1240 uintptr_t rsslim;
1241 uintptr_t scodes;
1242 uintptr_t ecode;
1243 int i;
1244
1245 // Figure what the primordial thread stack base is. Code is inspired
1246 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1247 // followed by command name surrounded by parentheses, state, etc.
1248 char stat[2048];
1249 int statlen;
1250
1251 fp = fopen("/proc/self/stat", "r");
1252 if (fp) {
1253 statlen = fread(stat, 1, 2047, fp);
1254 stat[statlen] = '\0';
1255 fclose(fp);
1256
1257 // Skip pid and the command string. Note that we could be dealing with
1258 // weird command names, e.g. user could decide to rename java launcher
1259 // to "java 1.4.2 :)", then the stat file would look like
1260 // 1234 (java 1.4.2 :)) R ... ...
1261 // We don't really need to know the command string, just find the last
1262 // occurrence of ")" and then start parsing from there. See bug 4726580.
1263 char * s = strrchr(stat, ')');
1264
1265 i = 0;
1266 if (s) {
1267 // Skip blank chars
1268 do s++; while (isspace(*s));
1269
1270 #define _UFM UINTX_FORMAT
1271 #define _DFM INTX_FORMAT
1272
1273 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1274 /* 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 */
1275 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,
1276 &state, /* 3 %c */
1277 &ppid, /* 4 %d */
1278 &pgrp, /* 5 %d */
1279 &session, /* 6 %d */
1280 &nr, /* 7 %d */
1281 &tpgrp, /* 8 %d */
1282 &flags, /* 9 %lu */
1283 &minflt, /* 10 %lu */
1284 &cminflt, /* 11 %lu */
1285 &majflt, /* 12 %lu */
1286 &cmajflt, /* 13 %lu */
1287 &utime, /* 14 %lu */
1288 &stime, /* 15 %lu */
1289 &cutime, /* 16 %ld */
1290 &cstime, /* 17 %ld */
1291 &prio, /* 18 %ld */
1292 &nice, /* 19 %ld */
1293 &junk, /* 20 %ld */
1294 &it_real, /* 21 %ld */
1295 &start, /* 22 UINTX_FORMAT */
1296 &vsize, /* 23 UINTX_FORMAT */
1297 &rss, /* 24 INTX_FORMAT */
1298 &rsslim, /* 25 UINTX_FORMAT */
1299 &scodes, /* 26 UINTX_FORMAT */
1300 &ecode, /* 27 UINTX_FORMAT */
1301 &stack_start); /* 28 UINTX_FORMAT */
1302 }
1303
1304 #undef _UFM
1305 #undef _DFM
1306
1307 if (i != 28 - 2) {
1308 assert(false, "Bad conversion from /proc/self/stat");
1309 // product mode - assume we are the initial thread, good luck in the
1310 // embedded case.
1311 warning("Can't detect initial thread stack location - bad conversion");
1312 stack_start = (uintptr_t) &rlim;
1313 }
1314 } else {
1315 // For some reason we can't open /proc/self/stat (for example, running on
1316 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1317 // most cases, so don't abort:
1318 warning("Can't detect initial thread stack location - no /proc/self/stat");
1319 stack_start = (uintptr_t) &rlim;
1320 }
1321 }
1322
1323 // Now we have a pointer (stack_start) very close to the stack top, the
1324 // next thing to do is to figure out the exact location of stack top. We
1325 // can find out the virtual memory area that contains stack_start by
1326 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1327 // and its upper limit is the real stack top. (again, this would fail if
1328 // running inside chroot, because /proc may not exist.)
1329
1330 uintptr_t stack_top;
1331 address low, high;
1332 if (find_vma((address)stack_start, &low, &high)) {
1333 // success, "high" is the true stack top. (ignore "low", because initial
1334 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1335 stack_top = (uintptr_t)high;
1336 } else {
1337 // failed, likely because /proc/self/maps does not exist
1338 warning("Can't detect initial thread stack location - find_vma failed");
1339 // best effort: stack_start is normally within a few pages below the real
1340 // stack top, use it as stack top, and reduce stack size so we won't put
1341 // guard page outside stack.
1342 stack_top = stack_start;
1343 stack_size -= 16 * page_size();
1344 }
1345
1346 // stack_top could be partially down the page so align it
1347 stack_top = align_size_up(stack_top, page_size());
1348
1349 if (max_size && stack_size > max_size) {
1350 _initial_thread_stack_size = max_size;
1351 } else {
1352 _initial_thread_stack_size = stack_size;
1353 }
1354
1355 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1356 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1357 }
1358
1359 ////////////////////////////////////////////////////////////////////////////////
1360 // time support
1361
1362 // Time since start-up in seconds to a fine granularity.
1363 // Used by VMSelfDestructTimer and the MemProfiler.
1364 double os::elapsedTime() {
1365
1366 return (double)(os::elapsed_counter()) * 0.000001;
1367 }
1368
1369 jlong os::elapsed_counter() {
1370 timeval time;
1371 int status = gettimeofday(&time, NULL);
1372 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1373 }
1374
1375 jlong os::elapsed_frequency() {
1376 return (1000 * 1000);
1377 }
1378
1379 // For now, we say that linux does not support vtime. I have no idea
1380 // whether it can actually be made to (DLD, 9/13/05).
1381
1382 bool os::supports_vtime() { return false; }
1383 bool os::enable_vtime() { return false; }
1384 bool os::vtime_enabled() { return false; }
1385 double os::elapsedVTime() {
1386 // better than nothing, but not much
1387 return elapsedTime();
1388 }
1389
1390 jlong os::javaTimeMillis() {
1391 timeval time;
1392 int status = gettimeofday(&time, NULL);
1393 assert(status != -1, "linux error");
1394 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1395 }
1396
1397 #ifndef CLOCK_MONOTONIC
1398 #define CLOCK_MONOTONIC (1)
1399 #endif
1400
1401 void os::Linux::clock_init() {
1402 // we do dlopen's in this particular order due to bug in linux
1403 // dynamical loader (see 6348968) leading to crash on exit
1404 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1405 if (handle == NULL) {
1406 handle = dlopen("librt.so", RTLD_LAZY);
1407 }
1408
1409 if (handle) {
1410 int (*clock_getres_func)(clockid_t, struct timespec*) =
1411 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1412 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1413 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1414 if (clock_getres_func && clock_gettime_func) {
1415 // See if monotonic clock is supported by the kernel. Note that some
1416 // early implementations simply return kernel jiffies (updated every
1417 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1418 // for nano time (though the monotonic property is still nice to have).
1419 // It's fixed in newer kernels, however clock_getres() still returns
1420 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1421 // resolution for now. Hopefully as people move to new kernels, this
1422 // won't be a problem.
1423 struct timespec res;
1424 struct timespec tp;
1425 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1426 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1427 // yes, monotonic clock is supported
1428 _clock_gettime = clock_gettime_func;
1429 } else {
1430 // close librt if there is no monotonic clock
1431 dlclose(handle);
1432 }
1433 }
1434 }
1435 }
1436
1437 #ifndef SYS_clock_getres
1438
1439 #if defined(IA32) || defined(AMD64)
1440 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1441 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1442 #else
1443 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1444 #define sys_clock_getres(x,y) -1
1445 #endif
1446
1447 #else
1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1449 #endif
1450
1451 void os::Linux::fast_thread_clock_init() {
1452 if (!UseLinuxPosixThreadCPUClocks) {
1453 return;
1454 }
1455 clockid_t clockid;
1456 struct timespec tp;
1457 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1458 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1459
1460 // Switch to using fast clocks for thread cpu time if
1461 // the sys_clock_getres() returns 0 error code.
1462 // Note, that some kernels may support the current thread
1463 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1464 // returned by the pthread_getcpuclockid().
1465 // If the fast Posix clocks are supported then the sys_clock_getres()
1466 // must return at least tp.tv_sec == 0 which means a resolution
1467 // better than 1 sec. This is extra check for reliability.
1468
1469 if(pthread_getcpuclockid_func &&
1470 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1471 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1472
1473 _supports_fast_thread_cpu_time = true;
1474 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1475 }
1476 }
1477
1478 jlong os::javaTimeNanos() {
1479 if (Linux::supports_monotonic_clock()) {
1480 struct timespec tp;
1481 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1482 assert(status == 0, "gettime error");
1483 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1484 return result;
1485 } else {
1486 timeval time;
1487 int status = gettimeofday(&time, NULL);
1488 assert(status != -1, "linux error");
1489 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1490 return 1000 * usecs;
1491 }
1492 }
1493
1494 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1495 if (Linux::supports_monotonic_clock()) {
1496 info_ptr->max_value = ALL_64_BITS;
1497
1498 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1499 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1500 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1501 } else {
1502 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1503 info_ptr->max_value = ALL_64_BITS;
1504
1505 // gettimeofday is a real time clock so it skips
1506 info_ptr->may_skip_backward = true;
1507 info_ptr->may_skip_forward = true;
1508 }
1509
1510 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1511 }
1512
1513 // Return the real, user, and system times in seconds from an
1514 // arbitrary fixed point in the past.
1515 bool os::getTimesSecs(double* process_real_time,
1516 double* process_user_time,
1517 double* process_system_time) {
1518 struct tms ticks;
1519 clock_t real_ticks = times(&ticks);
1520
1521 if (real_ticks == (clock_t) (-1)) {
1522 return false;
1523 } else {
1524 double ticks_per_second = (double) clock_tics_per_sec;
1525 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1526 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1527 *process_real_time = ((double) real_ticks) / ticks_per_second;
1528
1529 return true;
1530 }
1531 }
1532
1533
1534 char * os::local_time_string(char *buf, size_t buflen) {
1535 struct tm t;
1536 time_t long_time;
1537 time(&long_time);
1538 localtime_r(&long_time, &t);
1539 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1540 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1541 t.tm_hour, t.tm_min, t.tm_sec);
1542 return buf;
1543 }
1544
1545 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1546 return localtime_r(clock, res);
1547 }
1548
1549 ////////////////////////////////////////////////////////////////////////////////
1550 // runtime exit support
1551
1552 // Note: os::shutdown() might be called very early during initialization, or
1553 // called from signal handler. Before adding something to os::shutdown(), make
1554 // sure it is async-safe and can handle partially initialized VM.
1555 void os::shutdown() {
1556
1557 // allow PerfMemory to attempt cleanup of any persistent resources
1558 perfMemory_exit();
1559
1560 // needs to remove object in file system
1561 AttachListener::abort();
1562
1563 // flush buffered output, finish log files
1564 ostream_abort();
1565
1566 // Check for abort hook
1567 abort_hook_t abort_hook = Arguments::abort_hook();
1568 if (abort_hook != NULL) {
1569 abort_hook();
1570 }
1571
1572 }
1573
1574 // Note: os::abort() might be called very early during initialization, or
1575 // called from signal handler. Before adding something to os::abort(), make
1576 // sure it is async-safe and can handle partially initialized VM.
1577 void os::abort(bool dump_core) {
1578 os::shutdown();
1579 if (dump_core) {
1580 #ifndef PRODUCT
1581 fdStream out(defaultStream::output_fd());
1582 out.print_raw("Current thread is ");
1583 char buf[16];
1584 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1585 out.print_raw_cr(buf);
1586 out.print_raw_cr("Dumping core ...");
1587 #endif
1588 ::abort(); // dump core
1589 }
1590
1591 ::exit(1);
1592 }
1593
1594 // Die immediately, no exit hook, no abort hook, no cleanup.
1595 void os::die() {
1596 // _exit() on LinuxThreads only kills current thread
1597 ::abort();
1598 }
1599
1600 // unused on linux for now.
1601 void os::set_error_file(const char *logfile) {}
1602
1603
1604 // This method is a copy of JDK's sysGetLastErrorString
1605 // from src/solaris/hpi/src/system_md.c
1606
1607 size_t os::lasterror(char *buf, size_t len) {
1608
1609 if (errno == 0) return 0;
1610
1611 const char *s = ::strerror(errno);
1612 size_t n = ::strlen(s);
1613 if (n >= len) {
1614 n = len - 1;
1615 }
1616 ::strncpy(buf, s, n);
1617 buf[n] = '\0';
1618 return n;
1619 }
1620
1621 intx os::current_thread_id() { return (intx)pthread_self(); }
1622 int os::current_process_id() {
1623
1624 // Under the old linux thread library, linux gives each thread
1625 // its own process id. Because of this each thread will return
1626 // a different pid if this method were to return the result
1627 // of getpid(2). Linux provides no api that returns the pid
1628 // of the launcher thread for the vm. This implementation
1629 // returns a unique pid, the pid of the launcher thread
1630 // that starts the vm 'process'.
1631
1632 // Under the NPTL, getpid() returns the same pid as the
1633 // launcher thread rather than a unique pid per thread.
1634 // Use gettid() if you want the old pre NPTL behaviour.
1635
1636 // if you are looking for the result of a call to getpid() that
1637 // returns a unique pid for the calling thread, then look at the
1638 // OSThread::thread_id() method in osThread_linux.hpp file
1639
1640 return (int)(_initial_pid ? _initial_pid : getpid());
1641 }
1642
1643 // DLL functions
1644
1645 const char* os::dll_file_extension() { return ".so"; }
1646
1647 // This must be hard coded because it's the system's temporary
1648 // directory not the java application's temp directory, ala java.io.tmpdir.
1649 const char* os::get_temp_directory() { return "/tmp"; }
1650
1651 static bool file_exists(const char* filename) {
1652 struct stat statbuf;
1653 if (filename == NULL || strlen(filename) == 0) {
1654 return false;
1655 }
1656 return os::stat(filename, &statbuf) == 0;
1657 }
1658
1659 void os::dll_build_name(char* buffer, size_t buflen,
1660 const char* pname, const char* fname) {
1661 // Copied from libhpi
1662 const size_t pnamelen = pname ? strlen(pname) : 0;
1663
1664 // Quietly truncate on buffer overflow. Should be an error.
1665 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1666 *buffer = '\0';
1667 return;
1668 }
1669
1670 if (pnamelen == 0) {
1671 snprintf(buffer, buflen, "lib%s.so", fname);
1672 } else if (strchr(pname, *os::path_separator()) != NULL) {
1673 int n;
1674 char** pelements = split_path(pname, &n);
1675 for (int i = 0 ; i < n ; i++) {
1676 // Really shouldn't be NULL, but check can't hurt
1677 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1678 continue; // skip the empty path values
1679 }
1680 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1681 if (file_exists(buffer)) {
1682 break;
1683 }
1684 }
1685 // release the storage
1686 for (int i = 0 ; i < n ; i++) {
1687 if (pelements[i] != NULL) {
1688 FREE_C_HEAP_ARRAY(char, pelements[i]);
1689 }
1690 }
1691 if (pelements != NULL) {
1692 FREE_C_HEAP_ARRAY(char*, pelements);
1693 }
1694 } else {
1695 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1696 }
1697 }
1698
1699 const char* os::get_current_directory(char *buf, int buflen) {
1700 return getcwd(buf, buflen);
1701 }
1702
1703 // check if addr is inside libjvm[_g].so
1704 bool os::address_is_in_vm(address addr) {
1705 static address libjvm_base_addr;
1706 Dl_info dlinfo;
1707
1708 if (libjvm_base_addr == NULL) {
1709 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1710 libjvm_base_addr = (address)dlinfo.dli_fbase;
1711 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1712 }
1713
1714 if (dladdr((void *)addr, &dlinfo)) {
1715 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1716 }
1717
1718 return false;
1719 }
1720
1721 bool os::dll_address_to_function_name(address addr, char *buf,
1722 int buflen, int *offset) {
1723 Dl_info dlinfo;
1724
1725 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1726 if (buf != NULL) {
1727 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1728 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1729 }
1730 }
1731 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1732 return true;
1733 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1734 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1735 buf, buflen, offset, dlinfo.dli_fname)) {
1736 return true;
1737 }
1738 }
1739
1740 if (buf != NULL) buf[0] = '\0';
1741 if (offset != NULL) *offset = -1;
1742 return false;
1743 }
1744
1745 struct _address_to_library_name {
1746 address addr; // input : memory address
1747 size_t buflen; // size of fname
1748 char* fname; // output: library name
1749 address base; // library base addr
1750 };
1751
1752 static int address_to_library_name_callback(struct dl_phdr_info *info,
1753 size_t size, void *data) {
1754 int i;
1755 bool found = false;
1756 address libbase = NULL;
1757 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1758
1759 // iterate through all loadable segments
1760 for (i = 0; i < info->dlpi_phnum; i++) {
1761 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1762 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1763 // base address of a library is the lowest address of its loaded
1764 // segments.
1765 if (libbase == NULL || libbase > segbase) {
1766 libbase = segbase;
1767 }
1768 // see if 'addr' is within current segment
1769 if (segbase <= d->addr &&
1770 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1771 found = true;
1772 }
1773 }
1774 }
1775
1776 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1777 // so dll_address_to_library_name() can fall through to use dladdr() which
1778 // can figure out executable name from argv[0].
1779 if (found && info->dlpi_name && info->dlpi_name[0]) {
1780 d->base = libbase;
1781 if (d->fname) {
1782 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1783 }
1784 return 1;
1785 }
1786 return 0;
1787 }
1788
1789 bool os::dll_address_to_library_name(address addr, char* buf,
1790 int buflen, int* offset) {
1791 Dl_info dlinfo;
1792 struct _address_to_library_name data;
1793
1794 // There is a bug in old glibc dladdr() implementation that it could resolve
1795 // to wrong library name if the .so file has a base address != NULL. Here
1796 // we iterate through the program headers of all loaded libraries to find
1797 // out which library 'addr' really belongs to. This workaround can be
1798 // removed once the minimum requirement for glibc is moved to 2.3.x.
1799 data.addr = addr;
1800 data.fname = buf;
1801 data.buflen = buflen;
1802 data.base = NULL;
1803 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1804
1805 if (rslt) {
1806 // buf already contains library name
1807 if (offset) *offset = addr - data.base;
1808 return true;
1809 } else if (dladdr((void*)addr, &dlinfo)){
1810 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1811 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1812 return true;
1813 } else {
1814 if (buf) buf[0] = '\0';
1815 if (offset) *offset = -1;
1816 return false;
1817 }
1818 }
1819
1820 // Loads .dll/.so and
1821 // in case of error it checks if .dll/.so was built for the
1822 // same architecture as Hotspot is running on
1823
1824 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1825 {
1826 void * result= ::dlopen(filename, RTLD_LAZY);
1827 if (result != NULL) {
1828 // Successful loading
1829 return result;
1830 }
1831
1832 Elf32_Ehdr elf_head;
1833
1834 // Read system error message into ebuf
1835 // It may or may not be overwritten below
1836 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1837 ebuf[ebuflen-1]='\0';
1838 int diag_msg_max_length=ebuflen-strlen(ebuf);
1839 char* diag_msg_buf=ebuf+strlen(ebuf);
1840
1841 if (diag_msg_max_length==0) {
1842 // No more space in ebuf for additional diagnostics message
1843 return NULL;
1844 }
1845
1846
1847 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1848
1849 if (file_descriptor < 0) {
1850 // Can't open library, report dlerror() message
1851 return NULL;
1852 }
1853
1854 bool failed_to_read_elf_head=
1855 (sizeof(elf_head)!=
1856 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1857
1858 ::close(file_descriptor);
1859 if (failed_to_read_elf_head) {
1860 // file i/o error - report dlerror() msg
1861 return NULL;
1862 }
1863
1864 typedef struct {
1865 Elf32_Half code; // Actual value as defined in elf.h
1866 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1867 char elf_class; // 32 or 64 bit
1868 char endianess; // MSB or LSB
1869 char* name; // String representation
1870 } arch_t;
1871
1872 #ifndef EM_486
1873 #define EM_486 6 /* Intel 80486 */
1874 #endif
1875
1876 static const arch_t arch_array[]={
1877 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1878 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1879 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1880 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1881 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1882 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1883 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1884 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1885 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1886 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1887 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1888 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1889 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1890 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1891 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1892 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1893 };
1894
1895 #if (defined IA32)
1896 static Elf32_Half running_arch_code=EM_386;
1897 #elif (defined AMD64)
1898 static Elf32_Half running_arch_code=EM_X86_64;
1899 #elif (defined IA64)
1900 static Elf32_Half running_arch_code=EM_IA_64;
1901 #elif (defined __sparc) && (defined _LP64)
1902 static Elf32_Half running_arch_code=EM_SPARCV9;
1903 #elif (defined __sparc) && (!defined _LP64)
1904 static Elf32_Half running_arch_code=EM_SPARC;
1905 #elif (defined __powerpc64__)
1906 static Elf32_Half running_arch_code=EM_PPC64;
1907 #elif (defined __powerpc__)
1908 static Elf32_Half running_arch_code=EM_PPC;
1909 #elif (defined ARM)
1910 static Elf32_Half running_arch_code=EM_ARM;
1911 #elif (defined S390)
1912 static Elf32_Half running_arch_code=EM_S390;
1913 #elif (defined ALPHA)
1914 static Elf32_Half running_arch_code=EM_ALPHA;
1915 #elif (defined MIPSEL)
1916 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1917 #elif (defined PARISC)
1918 static Elf32_Half running_arch_code=EM_PARISC;
1919 #elif (defined MIPS)
1920 static Elf32_Half running_arch_code=EM_MIPS;
1921 #elif (defined M68K)
1922 static Elf32_Half running_arch_code=EM_68K;
1923 #else
1924 #error Method os::dll_load requires that one of following is defined:\
1925 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1926 #endif
1927
1928 // Identify compatability class for VM's architecture and library's architecture
1929 // Obtain string descriptions for architectures
1930
1931 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1932 int running_arch_index=-1;
1933
1934 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1935 if (running_arch_code == arch_array[i].code) {
1936 running_arch_index = i;
1937 }
1938 if (lib_arch.code == arch_array[i].code) {
1939 lib_arch.compat_class = arch_array[i].compat_class;
1940 lib_arch.name = arch_array[i].name;
1941 }
1942 }
1943
1944 assert(running_arch_index != -1,
1945 "Didn't find running architecture code (running_arch_code) in arch_array");
1946 if (running_arch_index == -1) {
1947 // Even though running architecture detection failed
1948 // we may still continue with reporting dlerror() message
1949 return NULL;
1950 }
1951
1952 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1954 return NULL;
1955 }
1956
1957 #ifndef S390
1958 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1960 return NULL;
1961 }
1962 #endif // !S390
1963
1964 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1965 if ( lib_arch.name!=NULL ) {
1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1967 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1968 lib_arch.name, arch_array[running_arch_index].name);
1969 } else {
1970 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1971 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1972 lib_arch.code,
1973 arch_array[running_arch_index].name);
1974 }
1975 }
1976
1977 return NULL;
1978 }
1979
1980 /*
1981 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1982 * chances are you might want to run the generated bits against glibc-2.0
1983 * libdl.so, so always use locking for any version of glibc.
1984 */
1985 void* os::dll_lookup(void* handle, const char* name) {
1986 pthread_mutex_lock(&dl_mutex);
1987 void* res = dlsym(handle, name);
1988 pthread_mutex_unlock(&dl_mutex);
1989 return res;
1990 }
1991
1992
1993 static bool _print_ascii_file(const char* filename, outputStream* st) {
1994 int fd = ::open(filename, O_RDONLY);
1995 if (fd == -1) {
1996 return false;
1997 }
1998
1999 char buf[32];
2000 int bytes;
2001 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2002 st->print_raw(buf, bytes);
2003 }
2004
2005 ::close(fd);
2006
2007 return true;
2008 }
2009
2010 void os::print_dll_info(outputStream *st) {
2011 st->print_cr("Dynamic libraries:");
2012
2013 char fname[32];
2014 pid_t pid = os::Linux::gettid();
2015
2016 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2017
2018 if (!_print_ascii_file(fname, st)) {
2019 st->print("Can not get library information for pid = %d\n", pid);
2020 }
2021 }
2022
2023
2024 void os::print_os_info(outputStream* st) {
2025 st->print("OS:");
2026
2027 // Try to identify popular distros.
2028 // Most Linux distributions have /etc/XXX-release file, which contains
2029 // the OS version string. Some have more than one /etc/XXX-release file
2030 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2031 // so the order is important.
2032 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2033 !_print_ascii_file("/etc/sun-release", st) &&
2034 !_print_ascii_file("/etc/redhat-release", st) &&
2035 !_print_ascii_file("/etc/SuSE-release", st) &&
2036 !_print_ascii_file("/etc/turbolinux-release", st) &&
2037 !_print_ascii_file("/etc/gentoo-release", st) &&
2038 !_print_ascii_file("/etc/debian_version", st) &&
2039 !_print_ascii_file("/etc/ltib-release", st) &&
2040 !_print_ascii_file("/etc/angstrom-version", st)) {
2041 st->print("Linux");
2042 }
2043 st->cr();
2044
2045 // kernel
2046 st->print("uname:");
2047 struct utsname name;
2048 uname(&name);
2049 st->print(name.sysname); st->print(" ");
2050 st->print(name.release); st->print(" ");
2051 st->print(name.version); st->print(" ");
2052 st->print(name.machine);
2053 st->cr();
2054
2055 // Print warning if unsafe chroot environment detected
2056 if (unsafe_chroot_detected) {
2057 st->print("WARNING!! ");
2058 st->print_cr(unstable_chroot_error);
2059 }
2060
2061 // libc, pthread
2062 st->print("libc:");
2063 st->print(os::Linux::glibc_version()); st->print(" ");
2064 st->print(os::Linux::libpthread_version()); st->print(" ");
2065 if (os::Linux::is_LinuxThreads()) {
2066 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2067 }
2068 st->cr();
2069
2070 // rlimit
2071 st->print("rlimit:");
2072 struct rlimit rlim;
2073
2074 st->print(" STACK ");
2075 getrlimit(RLIMIT_STACK, &rlim);
2076 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2077 else st->print("%uk", rlim.rlim_cur >> 10);
2078
2079 st->print(", CORE ");
2080 getrlimit(RLIMIT_CORE, &rlim);
2081 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2082 else st->print("%uk", rlim.rlim_cur >> 10);
2083
2084 st->print(", NPROC ");
2085 getrlimit(RLIMIT_NPROC, &rlim);
2086 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2087 else st->print("%d", rlim.rlim_cur);
2088
2089 st->print(", NOFILE ");
2090 getrlimit(RLIMIT_NOFILE, &rlim);
2091 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2092 else st->print("%d", rlim.rlim_cur);
2093
2094 st->print(", AS ");
2095 getrlimit(RLIMIT_AS, &rlim);
2096 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2097 else st->print("%uk", rlim.rlim_cur >> 10);
2098 st->cr();
2099
2100 // load average
2101 st->print("load average:");
2102 double loadavg[3];
2103 os::loadavg(loadavg, 3);
2104 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2105 st->cr();
2106
2107 // meminfo
2108 st->print("\n/proc/meminfo:\n");
2109 _print_ascii_file("/proc/meminfo", st);
2110 st->cr();
2111 }
2112
2113 void os::pd_print_cpu_info(outputStream* st) {
2114 st->print("\n/proc/cpuinfo:\n");
2115 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2116 st->print(" <Not Available>");
2117 }
2118 st->cr();
2119 }
2120
2121 void os::print_memory_info(outputStream* st) {
2122
2123 st->print("Memory:");
2124 st->print(" %dk page", os::vm_page_size()>>10);
2125
2126 // values in struct sysinfo are "unsigned long"
2127 struct sysinfo si;
2128 sysinfo(&si);
2129
2130 st->print(", physical " UINT64_FORMAT "k",
2131 os::physical_memory() >> 10);
2132 st->print("(" UINT64_FORMAT "k free)",
2133 os::available_memory() >> 10);
2134 st->print(", swap " UINT64_FORMAT "k",
2135 ((jlong)si.totalswap * si.mem_unit) >> 10);
2136 st->print("(" UINT64_FORMAT "k free)",
2137 ((jlong)si.freeswap * si.mem_unit) >> 10);
2138 st->cr();
2139 }
2140
2141 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2142 // but they're the same for all the linux arch that we support
2143 // and they're the same for solaris but there's no common place to put this.
2144 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2145 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2146 "ILL_COPROC", "ILL_BADSTK" };
2147
2148 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2149 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2150 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2151
2152 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2153
2154 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2155
2156 void os::print_siginfo(outputStream* st, void* siginfo) {
2157 st->print("siginfo:");
2158
2159 const int buflen = 100;
2160 char buf[buflen];
2161 siginfo_t *si = (siginfo_t*)siginfo;
2162 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2163 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2164 st->print("si_errno=%s", buf);
2165 } else {
2166 st->print("si_errno=%d", si->si_errno);
2167 }
2168 const int c = si->si_code;
2169 assert(c > 0, "unexpected si_code");
2170 switch (si->si_signo) {
2171 case SIGILL:
2172 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2173 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2174 break;
2175 case SIGFPE:
2176 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2177 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2178 break;
2179 case SIGSEGV:
2180 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2181 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2182 break;
2183 case SIGBUS:
2184 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2185 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2186 break;
2187 default:
2188 st->print(", si_code=%d", si->si_code);
2189 // no si_addr
2190 }
2191
2192 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2193 UseSharedSpaces) {
2194 FileMapInfo* mapinfo = FileMapInfo::current_info();
2195 if (mapinfo->is_in_shared_space(si->si_addr)) {
2196 st->print("\n\nError accessing class data sharing archive." \
2197 " Mapped file inaccessible during execution, " \
2198 " possible disk/network problem.");
2199 }
2200 }
2201 st->cr();
2202 }
2203
2204
2205 static void print_signal_handler(outputStream* st, int sig,
2206 char* buf, size_t buflen);
2207
2208 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2209 st->print_cr("Signal Handlers:");
2210 print_signal_handler(st, SIGSEGV, buf, buflen);
2211 print_signal_handler(st, SIGBUS , buf, buflen);
2212 print_signal_handler(st, SIGFPE , buf, buflen);
2213 print_signal_handler(st, SIGPIPE, buf, buflen);
2214 print_signal_handler(st, SIGXFSZ, buf, buflen);
2215 print_signal_handler(st, SIGILL , buf, buflen);
2216 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2217 print_signal_handler(st, SR_signum, buf, buflen);
2218 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2219 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2220 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2221 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2222 }
2223
2224 static char saved_jvm_path[MAXPATHLEN] = {0};
2225
2226 // Find the full path to the current module, libjvm.so or libjvm_g.so
2227 void os::jvm_path(char *buf, jint buflen) {
2228 // Error checking.
2229 if (buflen < MAXPATHLEN) {
2230 assert(false, "must use a large-enough buffer");
2231 buf[0] = '\0';
2232 return;
2233 }
2234 // Lazy resolve the path to current module.
2235 if (saved_jvm_path[0] != 0) {
2236 strcpy(buf, saved_jvm_path);
2237 return;
2238 }
2239
2240 char dli_fname[MAXPATHLEN];
2241 bool ret = dll_address_to_library_name(
2242 CAST_FROM_FN_PTR(address, os::jvm_path),
2243 dli_fname, sizeof(dli_fname), NULL);
2244 assert(ret != 0, "cannot locate libjvm");
2245 char *rp = realpath(dli_fname, buf);
2246 if (rp == NULL)
2247 return;
2248
2249 if (Arguments::created_by_gamma_launcher()) {
2250 // Support for the gamma launcher. Typical value for buf is
2251 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2252 // the right place in the string, then assume we are installed in a JDK and
2253 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2254 // up the path so it looks like libjvm.so is installed there (append a
2255 // fake suffix hotspot/libjvm.so).
2256 const char *p = buf + strlen(buf) - 1;
2257 for (int count = 0; p > buf && count < 5; ++count) {
2258 for (--p; p > buf && *p != '/'; --p)
2259 /* empty */ ;
2260 }
2261
2262 if (strncmp(p, "/jre/lib/", 9) != 0) {
2263 // Look for JAVA_HOME in the environment.
2264 char* java_home_var = ::getenv("JAVA_HOME");
2265 if (java_home_var != NULL && java_home_var[0] != 0) {
2266 char* jrelib_p;
2267 int len;
2268
2269 // Check the current module name "libjvm.so" or "libjvm_g.so".
2270 p = strrchr(buf, '/');
2271 assert(strstr(p, "/libjvm") == p, "invalid library name");
2272 p = strstr(p, "_g") ? "_g" : "";
2273
2274 rp = realpath(java_home_var, buf);
2275 if (rp == NULL)
2276 return;
2277
2278 // determine if this is a legacy image or modules image
2279 // modules image doesn't have "jre" subdirectory
2280 len = strlen(buf);
2281 jrelib_p = buf + len;
2282 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2283 if (0 != access(buf, F_OK)) {
2284 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2285 }
2286
2287 if (0 == access(buf, F_OK)) {
2288 // Use current module name "libjvm[_g].so" instead of
2289 // "libjvm"debug_only("_g")".so" since for fastdebug version
2290 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2291 len = strlen(buf);
2292 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2293 } else {
2294 // Go back to path of .so
2295 rp = realpath(dli_fname, buf);
2296 if (rp == NULL)
2297 return;
2298 }
2299 }
2300 }
2301 }
2302
2303 strcpy(saved_jvm_path, buf);
2304 }
2305
2306 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2307 // no prefix required, not even "_"
2308 }
2309
2310 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2311 // no suffix required
2312 }
2313
2314 ////////////////////////////////////////////////////////////////////////////////
2315 // sun.misc.Signal support
2316
2317 static volatile jint sigint_count = 0;
2318
2319 static void
2320 UserHandler(int sig, void *siginfo, void *context) {
2321 // 4511530 - sem_post is serialized and handled by the manager thread. When
2322 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2323 // don't want to flood the manager thread with sem_post requests.
2324 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2325 return;
2326
2327 // Ctrl-C is pressed during error reporting, likely because the error
2328 // handler fails to abort. Let VM die immediately.
2329 if (sig == SIGINT && is_error_reported()) {
2330 os::die();
2331 }
2332
2333 os::signal_notify(sig);
2334 }
2335
2336 void* os::user_handler() {
2337 return CAST_FROM_FN_PTR(void*, UserHandler);
2338 }
2339
2340 extern "C" {
2341 typedef void (*sa_handler_t)(int);
2342 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2343 }
2344
2345 void* os::signal(int signal_number, void* handler) {
2346 struct sigaction sigAct, oldSigAct;
2347
2348 sigfillset(&(sigAct.sa_mask));
2349 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2350 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2351
2352 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2353 // -1 means registration failed
2354 return (void *)-1;
2355 }
2356
2357 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2358 }
2359
2360 void os::signal_raise(int signal_number) {
2361 ::raise(signal_number);
2362 }
2363
2364 /*
2365 * The following code is moved from os.cpp for making this
2366 * code platform specific, which it is by its very nature.
2367 */
2368
2369 // Will be modified when max signal is changed to be dynamic
2370 int os::sigexitnum_pd() {
2371 return NSIG;
2372 }
2373
2374 // a counter for each possible signal value
2375 static volatile jint pending_signals[NSIG+1] = { 0 };
2376
2377 // Linux(POSIX) specific hand shaking semaphore.
2378 static sem_t sig_sem;
2379
2380 void os::signal_init_pd() {
2381 // Initialize signal structures
2382 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2383
2384 // Initialize signal semaphore
2385 ::sem_init(&sig_sem, 0, 0);
2386 }
2387
2388 void os::signal_notify(int sig) {
2389 Atomic::inc(&pending_signals[sig]);
2390 ::sem_post(&sig_sem);
2391 }
2392
2393 static int check_pending_signals(bool wait) {
2394 Atomic::store(0, &sigint_count);
2395 for (;;) {
2396 for (int i = 0; i < NSIG + 1; i++) {
2397 jint n = pending_signals[i];
2398 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2399 return i;
2400 }
2401 }
2402 if (!wait) {
2403 return -1;
2404 }
2405 JavaThread *thread = JavaThread::current();
2406 ThreadBlockInVM tbivm(thread);
2407
2408 bool threadIsSuspended;
2409 do {
2410 thread->set_suspend_equivalent();
2411 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2412 ::sem_wait(&sig_sem);
2413
2414 // were we externally suspended while we were waiting?
2415 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2416 if (threadIsSuspended) {
2417 //
2418 // The semaphore has been incremented, but while we were waiting
2419 // another thread suspended us. We don't want to continue running
2420 // while suspended because that would surprise the thread that
2421 // suspended us.
2422 //
2423 ::sem_post(&sig_sem);
2424
2425 thread->java_suspend_self();
2426 }
2427 } while (threadIsSuspended);
2428 }
2429 }
2430
2431 int os::signal_lookup() {
2432 return check_pending_signals(false);
2433 }
2434
2435 int os::signal_wait() {
2436 return check_pending_signals(true);
2437 }
2438
2439 ////////////////////////////////////////////////////////////////////////////////
2440 // Virtual Memory
2441
2442 int os::vm_page_size() {
2443 // Seems redundant as all get out
2444 assert(os::Linux::page_size() != -1, "must call os::init");
2445 return os::Linux::page_size();
2446 }
2447
2448 // Solaris allocates memory by pages.
2449 int os::vm_allocation_granularity() {
2450 assert(os::Linux::page_size() != -1, "must call os::init");
2451 return os::Linux::page_size();
2452 }
2453
2454 // Rationale behind this function:
2455 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2456 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2457 // samples for JITted code. Here we create private executable mapping over the code cache
2458 // and then we can use standard (well, almost, as mapping can change) way to provide
2459 // info for the reporting script by storing timestamp and location of symbol
2460 void linux_wrap_code(char* base, size_t size) {
2461 static volatile jint cnt = 0;
2462
2463 if (!UseOprofile) {
2464 return;
2465 }
2466
2467 char buf[PATH_MAX+1];
2468 int num = Atomic::add(1, &cnt);
2469
2470 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2471 os::get_temp_directory(), os::current_process_id(), num);
2472 unlink(buf);
2473
2474 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2475
2476 if (fd != -1) {
2477 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2478 if (rv != (off_t)-1) {
2479 if (::write(fd, "", 1) == 1) {
2480 mmap(base, size,
2481 PROT_READ|PROT_WRITE|PROT_EXEC,
2482 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2483 }
2484 }
2485 ::close(fd);
2486 unlink(buf);
2487 }
2488 }
2489
2490 // NOTE: Linux kernel does not really reserve the pages for us.
2491 // All it does is to check if there are enough free pages
2492 // left at the time of mmap(). This could be a potential
2493 // problem.
2494 bool os::commit_memory(char* addr, size_t size, bool exec) {
2495 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2496 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2497 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2498 if (res != (uintptr_t) MAP_FAILED) {
2499 if (UseNUMAInterleaving) {
2500 numa_make_global(addr, size);
2501 }
2502 return true;
2503 }
2504 return false;
2505 }
2506
2507 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2508 #ifndef MAP_HUGETLB
2509 #define MAP_HUGETLB 0x40000
2510 #endif
2511
2512 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2513 #ifndef MADV_HUGEPAGE
2514 #define MADV_HUGEPAGE 14
2515 #endif
2516
2517 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2518 bool exec) {
2519 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2520 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2521 uintptr_t res =
2522 (uintptr_t) ::mmap(addr, size, prot,
2523 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2524 -1, 0);
2525 if (res != (uintptr_t) MAP_FAILED) {
2526 if (UseNUMAInterleaving) {
2527 numa_make_global(addr, size);
2528 }
2529 return true;
2530 }
2531 // Fall through and try to use small pages
2532 }
2533
2534 if (commit_memory(addr, size, exec)) {
2535 realign_memory(addr, size, alignment_hint);
2536 return true;
2537 }
2538 return false;
2539 }
2540
2541 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2542 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2543 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2544 // be supported or the memory may already be backed by huge pages.
2545 ::madvise(addr, bytes, MADV_HUGEPAGE);
2546 }
2547 }
2548
2549 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2550 commit_memory(addr, bytes, alignment_hint, false);
2551 }
2552
2553 void os::numa_make_global(char *addr, size_t bytes) {
2554 Linux::numa_interleave_memory(addr, bytes);
2555 }
2556
2557 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2558 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2559 }
2560
2561 bool os::numa_topology_changed() { return false; }
2562
2563 size_t os::numa_get_groups_num() {
2564 int max_node = Linux::numa_max_node();
2565 return max_node > 0 ? max_node + 1 : 1;
2566 }
2567
2568 int os::numa_get_group_id() {
2569 int cpu_id = Linux::sched_getcpu();
2570 if (cpu_id != -1) {
2571 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2572 if (lgrp_id != -1) {
2573 return lgrp_id;
2574 }
2575 }
2576 return 0;
2577 }
2578
2579 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2580 for (size_t i = 0; i < size; i++) {
2581 ids[i] = i;
2582 }
2583 return size;
2584 }
2585
2586 bool os::get_page_info(char *start, page_info* info) {
2587 return false;
2588 }
2589
2590 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2591 return end;
2592 }
2593
2594
2595 int os::Linux::sched_getcpu_syscall(void) {
2596 unsigned int cpu;
2597 int retval = -1;
2598
2599 #if defined(IA32)
2600 # ifndef SYS_getcpu
2601 # define SYS_getcpu 318
2602 # endif
2603 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2604 #elif defined(AMD64)
2605 // Unfortunately we have to bring all these macros here from vsyscall.h
2606 // to be able to compile on old linuxes.
2607 # define __NR_vgetcpu 2
2608 # define VSYSCALL_START (-10UL << 20)
2609 # define VSYSCALL_SIZE 1024
2610 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2611 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2612 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2613 retval = vgetcpu(&cpu, NULL, NULL);
2614 #endif
2615
2616 return (retval == -1) ? retval : cpu;
2617 }
2618
2619 // Something to do with the numa-aware allocator needs these symbols
2620 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2621 extern "C" JNIEXPORT void numa_error(char *where) { }
2622 extern "C" JNIEXPORT int fork1() { return fork(); }
2623
2624
2625 // If we are running with libnuma version > 2, then we should
2626 // be trying to use symbols with versions 1.1
2627 // If we are running with earlier version, which did not have symbol versions,
2628 // we should use the base version.
2629 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2630 void *f = dlvsym(handle, name, "libnuma_1.1");
2631 if (f == NULL) {
2632 f = dlsym(handle, name);
2633 }
2634 return f;
2635 }
2636
2637 bool os::Linux::libnuma_init() {
2638 // sched_getcpu() should be in libc.
2639 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2640 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2641
2642 // If it's not, try a direct syscall.
2643 if (sched_getcpu() == -1)
2644 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2645
2646 if (sched_getcpu() != -1) { // Does it work?
2647 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2648 if (handle != NULL) {
2649 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2650 libnuma_dlsym(handle, "numa_node_to_cpus")));
2651 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2652 libnuma_dlsym(handle, "numa_max_node")));
2653 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2654 libnuma_dlsym(handle, "numa_available")));
2655 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2656 libnuma_dlsym(handle, "numa_tonode_memory")));
2657 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2658 libnuma_dlsym(handle, "numa_interleave_memory")));
2659
2660
2661 if (numa_available() != -1) {
2662 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2663 // Create a cpu -> node mapping
2664 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2665 rebuild_cpu_to_node_map();
2666 return true;
2667 }
2668 }
2669 }
2670 return false;
2671 }
2672
2673 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2674 // The table is later used in get_node_by_cpu().
2675 void os::Linux::rebuild_cpu_to_node_map() {
2676 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2677 // in libnuma (possible values are starting from 16,
2678 // and continuing up with every other power of 2, but less
2679 // than the maximum number of CPUs supported by kernel), and
2680 // is a subject to change (in libnuma version 2 the requirements
2681 // are more reasonable) we'll just hardcode the number they use
2682 // in the library.
2683 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2684
2685 size_t cpu_num = os::active_processor_count();
2686 size_t cpu_map_size = NCPUS / BitsPerCLong;
2687 size_t cpu_map_valid_size =
2688 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2689
2690 cpu_to_node()->clear();
2691 cpu_to_node()->at_grow(cpu_num - 1);
2692 size_t node_num = numa_get_groups_num();
2693
2694 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2695 for (size_t i = 0; i < node_num; i++) {
2696 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2697 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2698 if (cpu_map[j] != 0) {
2699 for (size_t k = 0; k < BitsPerCLong; k++) {
2700 if (cpu_map[j] & (1UL << k)) {
2701 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2702 }
2703 }
2704 }
2705 }
2706 }
2707 }
2708 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2709 }
2710
2711 int os::Linux::get_node_by_cpu(int cpu_id) {
2712 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2713 return cpu_to_node()->at(cpu_id);
2714 }
2715 return -1;
2716 }
2717
2718 GrowableArray<int>* os::Linux::_cpu_to_node;
2719 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2720 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2721 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2722 os::Linux::numa_available_func_t os::Linux::_numa_available;
2723 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2724 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2725 unsigned long* os::Linux::_numa_all_nodes;
2726
2727 bool os::uncommit_memory(char* addr, size_t size) {
2728 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2729 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2730 return res != (uintptr_t) MAP_FAILED;
2731 }
2732
2733 // Linux uses a growable mapping for the stack, and if the mapping for
2734 // the stack guard pages is not removed when we detach a thread the
2735 // stack cannot grow beyond the pages where the stack guard was
2736 // mapped. If at some point later in the process the stack expands to
2737 // that point, the Linux kernel cannot expand the stack any further
2738 // because the guard pages are in the way, and a segfault occurs.
2739 //
2740 // However, it's essential not to split the stack region by unmapping
2741 // a region (leaving a hole) that's already part of the stack mapping,
2742 // so if the stack mapping has already grown beyond the guard pages at
2743 // the time we create them, we have to truncate the stack mapping.
2744 // So, we need to know the extent of the stack mapping when
2745 // create_stack_guard_pages() is called.
2746
2747 // Find the bounds of the stack mapping. Return true for success.
2748 //
2749 // We only need this for stacks that are growable: at the time of
2750 // writing thread stacks don't use growable mappings (i.e. those
2751 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2752 // only applies to the main thread.
2753
2754 static
2755 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2756
2757 char buf[128];
2758 int fd, sz;
2759
2760 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2761 return false;
2762 }
2763
2764 const char kw[] = "[stack]";
2765 const int kwlen = sizeof(kw)-1;
2766
2767 // Address part of /proc/self/maps couldn't be more than 128 bytes
2768 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2769 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2770 // Extract addresses
2771 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2772 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2773 if (sp >= *bottom && sp <= *top) {
2774 ::close(fd);
2775 return true;
2776 }
2777 }
2778 }
2779 }
2780
2781 ::close(fd);
2782 return false;
2783 }
2784
2785
2786 // If the (growable) stack mapping already extends beyond the point
2787 // where we're going to put our guard pages, truncate the mapping at
2788 // that point by munmap()ping it. This ensures that when we later
2789 // munmap() the guard pages we don't leave a hole in the stack
2790 // mapping. This only affects the main/initial thread, but guard
2791 // against future OS changes
2792 bool os::create_stack_guard_pages(char* addr, size_t size) {
2793 uintptr_t stack_extent, stack_base;
2794 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2795 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2796 assert(os::Linux::is_initial_thread(),
2797 "growable stack in non-initial thread");
2798 if (stack_extent < (uintptr_t)addr)
2799 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2800 }
2801
2802 return os::commit_memory(addr, size);
2803 }
2804
2805 // If this is a growable mapping, remove the guard pages entirely by
2806 // munmap()ping them. If not, just call uncommit_memory(). This only
2807 // affects the main/initial thread, but guard against future OS changes
2808 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2809 uintptr_t stack_extent, stack_base;
2810 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2811 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2812 assert(os::Linux::is_initial_thread(),
2813 "growable stack in non-initial thread");
2814
2815 return ::munmap(addr, size) == 0;
2816 }
2817
2818 return os::uncommit_memory(addr, size);
2819 }
2820
2821 static address _highest_vm_reserved_address = NULL;
2822
2823 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2824 // at 'requested_addr'. If there are existing memory mappings at the same
2825 // location, however, they will be overwritten. If 'fixed' is false,
2826 // 'requested_addr' is only treated as a hint, the return value may or
2827 // may not start from the requested address. Unlike Linux mmap(), this
2828 // function returns NULL to indicate failure.
2829 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2830 char * addr;
2831 int flags;
2832
2833 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2834 if (fixed) {
2835 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2836 flags |= MAP_FIXED;
2837 }
2838
2839 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2840 // to PROT_EXEC if executable when we commit the page.
2841 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2842 flags, -1, 0);
2843
2844 if (addr != MAP_FAILED) {
2845 // anon_mmap() should only get called during VM initialization,
2846 // don't need lock (actually we can skip locking even it can be called
2847 // from multiple threads, because _highest_vm_reserved_address is just a
2848 // hint about the upper limit of non-stack memory regions.)
2849 if ((address)addr + bytes > _highest_vm_reserved_address) {
2850 _highest_vm_reserved_address = (address)addr + bytes;
2851 }
2852 }
2853
2854 return addr == MAP_FAILED ? NULL : addr;
2855 }
2856
2857 // Don't update _highest_vm_reserved_address, because there might be memory
2858 // regions above addr + size. If so, releasing a memory region only creates
2859 // a hole in the address space, it doesn't help prevent heap-stack collision.
2860 //
2861 static int anon_munmap(char * addr, size_t size) {
2862 return ::munmap(addr, size) == 0;
2863 }
2864
2865 char* os::reserve_memory(size_t bytes, char* requested_addr,
2866 size_t alignment_hint) {
2867 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2868 }
2869
2870 bool os::release_memory(char* addr, size_t size) {
2871 return anon_munmap(addr, size);
2872 }
2873
2874 static address highest_vm_reserved_address() {
2875 return _highest_vm_reserved_address;
2876 }
2877
2878 static bool linux_mprotect(char* addr, size_t size, int prot) {
2879 // Linux wants the mprotect address argument to be page aligned.
2880 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2881
2882 // According to SUSv3, mprotect() should only be used with mappings
2883 // established by mmap(), and mmap() always maps whole pages. Unaligned
2884 // 'addr' likely indicates problem in the VM (e.g. trying to change
2885 // protection of malloc'ed or statically allocated memory). Check the
2886 // caller if you hit this assert.
2887 assert(addr == bottom, "sanity check");
2888
2889 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2890 return ::mprotect(bottom, size, prot) == 0;
2891 }
2892
2893 // Set protections specified
2894 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2895 bool is_committed) {
2896 unsigned int p = 0;
2897 switch (prot) {
2898 case MEM_PROT_NONE: p = PROT_NONE; break;
2899 case MEM_PROT_READ: p = PROT_READ; break;
2900 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2901 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2902 default:
2903 ShouldNotReachHere();
2904 }
2905 // is_committed is unused.
2906 return linux_mprotect(addr, bytes, p);
2907 }
2908
2909 bool os::guard_memory(char* addr, size_t size) {
2910 return linux_mprotect(addr, size, PROT_NONE);
2911 }
2912
2913 bool os::unguard_memory(char* addr, size_t size) {
2914 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2915 }
2916
2917 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2918 bool result = false;
2919 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2920 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2921 -1, 0);
2922
2923 if (p != (void *) -1) {
2924 // We don't know if this really is a huge page or not.
2925 FILE *fp = fopen("/proc/self/maps", "r");
2926 if (fp) {
2927 while (!feof(fp)) {
2928 char chars[257];
2929 long x = 0;
2930 if (fgets(chars, sizeof(chars), fp)) {
2931 if (sscanf(chars, "%lx-%*x", &x) == 1
2932 && x == (long)p) {
2933 if (strstr (chars, "hugepage")) {
2934 result = true;
2935 break;
2936 }
2937 }
2938 }
2939 }
2940 fclose(fp);
2941 }
2942 munmap (p, page_size);
2943 if (result)
2944 return true;
2945 }
2946
2947 if (warn) {
2948 warning("HugeTLBFS is not supported by the operating system.");
2949 }
2950
2951 return result;
2952 }
2953
2954 /*
2955 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2956 *
2957 * From the coredump_filter documentation:
2958 *
2959 * - (bit 0) anonymous private memory
2960 * - (bit 1) anonymous shared memory
2961 * - (bit 2) file-backed private memory
2962 * - (bit 3) file-backed shared memory
2963 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2964 * effective only if the bit 2 is cleared)
2965 * - (bit 5) hugetlb private memory
2966 * - (bit 6) hugetlb shared memory
2967 */
2968 static void set_coredump_filter(void) {
2969 FILE *f;
2970 long cdm;
2971
2972 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2973 return;
2974 }
2975
2976 if (fscanf(f, "%lx", &cdm) != 1) {
2977 fclose(f);
2978 return;
2979 }
2980
2981 rewind(f);
2982
2983 if ((cdm & LARGEPAGES_BIT) == 0) {
2984 cdm |= LARGEPAGES_BIT;
2985 fprintf(f, "%#lx", cdm);
2986 }
2987
2988 fclose(f);
2989 }
2990
2991 // Large page support
2992
2993 static size_t _large_page_size = 0;
2994
2995 void os::large_page_init() {
2996 if (!UseLargePages) {
2997 UseHugeTLBFS = false;
2998 UseSHM = false;
2999 return;
3000 }
3001
3002 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
3003 // If UseLargePages is specified on the command line try both methods,
3004 // if it's default, then try only HugeTLBFS.
3005 if (FLAG_IS_DEFAULT(UseLargePages)) {
3006 UseHugeTLBFS = true;
3007 } else {
3008 UseHugeTLBFS = UseSHM = true;
3009 }
3010 }
3011
3012 if (LargePageSizeInBytes) {
3013 _large_page_size = LargePageSizeInBytes;
3014 } else {
3015 // large_page_size on Linux is used to round up heap size. x86 uses either
3016 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3017 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3018 // page as large as 256M.
3019 //
3020 // Here we try to figure out page size by parsing /proc/meminfo and looking
3021 // for a line with the following format:
3022 // Hugepagesize: 2048 kB
3023 //
3024 // If we can't determine the value (e.g. /proc is not mounted, or the text
3025 // format has been changed), we'll use the largest page size supported by
3026 // the processor.
3027
3028 #ifndef ZERO
3029 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3030 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3031 #endif // ZERO
3032
3033 FILE *fp = fopen("/proc/meminfo", "r");
3034 if (fp) {
3035 while (!feof(fp)) {
3036 int x = 0;
3037 char buf[16];
3038 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3039 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3040 _large_page_size = x * K;
3041 break;
3042 }
3043 } else {
3044 // skip to next line
3045 for (;;) {
3046 int ch = fgetc(fp);
3047 if (ch == EOF || ch == (int)'\n') break;
3048 }
3049 }
3050 }
3051 fclose(fp);
3052 }
3053 }
3054
3055 // print a warning if any large page related flag is specified on command line
3056 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3057
3058 const size_t default_page_size = (size_t)Linux::page_size();
3059 if (_large_page_size > default_page_size) {
3060 _page_sizes[0] = _large_page_size;
3061 _page_sizes[1] = default_page_size;
3062 _page_sizes[2] = 0;
3063 }
3064 UseHugeTLBFS = UseHugeTLBFS &&
3065 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3066
3067 if (UseHugeTLBFS)
3068 UseSHM = false;
3069
3070 UseLargePages = UseHugeTLBFS || UseSHM;
3071
3072 set_coredump_filter();
3073 }
3074
3075 #ifndef SHM_HUGETLB
3076 #define SHM_HUGETLB 04000
3077 #endif
3078
3079 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3080 // "exec" is passed in but not used. Creating the shared image for
3081 // the code cache doesn't have an SHM_X executable permission to check.
3082 assert(UseLargePages && UseSHM, "only for SHM large pages");
3083
3084 key_t key = IPC_PRIVATE;
3085 char *addr;
3086
3087 bool warn_on_failure = UseLargePages &&
3088 (!FLAG_IS_DEFAULT(UseLargePages) ||
3089 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3090 );
3091 char msg[128];
3092
3093 // Create a large shared memory region to attach to based on size.
3094 // Currently, size is the total size of the heap
3095 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3096 if (shmid == -1) {
3097 // Possible reasons for shmget failure:
3098 // 1. shmmax is too small for Java heap.
3099 // > check shmmax value: cat /proc/sys/kernel/shmmax
3100 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3101 // 2. not enough large page memory.
3102 // > check available large pages: cat /proc/meminfo
3103 // > increase amount of large pages:
3104 // echo new_value > /proc/sys/vm/nr_hugepages
3105 // Note 1: different Linux may use different name for this property,
3106 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3107 // Note 2: it's possible there's enough physical memory available but
3108 // they are so fragmented after a long run that they can't
3109 // coalesce into large pages. Try to reserve large pages when
3110 // the system is still "fresh".
3111 if (warn_on_failure) {
3112 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3113 warning(msg);
3114 }
3115 return NULL;
3116 }
3117
3118 // attach to the region
3119 addr = (char*)shmat(shmid, req_addr, 0);
3120 int err = errno;
3121
3122 // Remove shmid. If shmat() is successful, the actual shared memory segment
3123 // will be deleted when it's detached by shmdt() or when the process
3124 // terminates. If shmat() is not successful this will remove the shared
3125 // segment immediately.
3126 shmctl(shmid, IPC_RMID, NULL);
3127
3128 if ((intptr_t)addr == -1) {
3129 if (warn_on_failure) {
3130 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3131 warning(msg);
3132 }
3133 return NULL;
3134 }
3135
3136 if ((addr != NULL) && UseNUMAInterleaving) {
3137 numa_make_global(addr, bytes);
3138 }
3139
3140 return addr;
3141 }
3142
3143 bool os::release_memory_special(char* base, size_t bytes) {
3144 // detaching the SHM segment will also delete it, see reserve_memory_special()
3145 int rslt = shmdt(base);
3146 return rslt == 0;
3147 }
3148
3149 size_t os::large_page_size() {
3150 return _large_page_size;
3151 }
3152
3153 // HugeTLBFS allows application to commit large page memory on demand;
3154 // with SysV SHM the entire memory region must be allocated as shared
3155 // memory.
3156 bool os::can_commit_large_page_memory() {
3157 return UseHugeTLBFS;
3158 }
3159
3160 bool os::can_execute_large_page_memory() {
3161 return UseHugeTLBFS;
3162 }
3163
3164 // Reserve memory at an arbitrary address, only if that area is
3165 // available (and not reserved for something else).
3166
3167 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3168 const int max_tries = 10;
3169 char* base[max_tries];
3170 size_t size[max_tries];
3171 const size_t gap = 0x000000;
3172
3173 // Assert only that the size is a multiple of the page size, since
3174 // that's all that mmap requires, and since that's all we really know
3175 // about at this low abstraction level. If we need higher alignment,
3176 // we can either pass an alignment to this method or verify alignment
3177 // in one of the methods further up the call chain. See bug 5044738.
3178 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3179
3180 // Repeatedly allocate blocks until the block is allocated at the
3181 // right spot. Give up after max_tries. Note that reserve_memory() will
3182 // automatically update _highest_vm_reserved_address if the call is
3183 // successful. The variable tracks the highest memory address every reserved
3184 // by JVM. It is used to detect heap-stack collision if running with
3185 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3186 // space than needed, it could confuse the collision detecting code. To
3187 // solve the problem, save current _highest_vm_reserved_address and
3188 // calculate the correct value before return.
3189 address old_highest = _highest_vm_reserved_address;
3190
3191 // Linux mmap allows caller to pass an address as hint; give it a try first,
3192 // if kernel honors the hint then we can return immediately.
3193 char * addr = anon_mmap(requested_addr, bytes, false);
3194 if (addr == requested_addr) {
3195 return requested_addr;
3196 }
3197
3198 if (addr != NULL) {
3199 // mmap() is successful but it fails to reserve at the requested address
3200 anon_munmap(addr, bytes);
3201 }
3202
3203 int i;
3204 for (i = 0; i < max_tries; ++i) {
3205 base[i] = reserve_memory(bytes);
3206
3207 if (base[i] != NULL) {
3208 // Is this the block we wanted?
3209 if (base[i] == requested_addr) {
3210 size[i] = bytes;
3211 break;
3212 }
3213
3214 // Does this overlap the block we wanted? Give back the overlapped
3215 // parts and try again.
3216
3217 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3218 if (top_overlap >= 0 && top_overlap < bytes) {
3219 unmap_memory(base[i], top_overlap);
3220 base[i] += top_overlap;
3221 size[i] = bytes - top_overlap;
3222 } else {
3223 size_t bottom_overlap = base[i] + bytes - requested_addr;
3224 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3225 unmap_memory(requested_addr, bottom_overlap);
3226 size[i] = bytes - bottom_overlap;
3227 } else {
3228 size[i] = bytes;
3229 }
3230 }
3231 }
3232 }
3233
3234 // Give back the unused reserved pieces.
3235
3236 for (int j = 0; j < i; ++j) {
3237 if (base[j] != NULL) {
3238 unmap_memory(base[j], size[j]);
3239 }
3240 }
3241
3242 if (i < max_tries) {
3243 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3244 return requested_addr;
3245 } else {
3246 _highest_vm_reserved_address = old_highest;
3247 return NULL;
3248 }
3249 }
3250
3251 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3252 return ::read(fd, buf, nBytes);
3253 }
3254
3255 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3256 // Solaris uses poll(), linux uses park().
3257 // Poll() is likely a better choice, assuming that Thread.interrupt()
3258 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3259 // SIGSEGV, see 4355769.
3260
3261 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3262 assert(thread == Thread::current(), "thread consistency check");
3263
3264 ParkEvent * const slp = thread->_SleepEvent ;
3265 slp->reset() ;
3266 OrderAccess::fence() ;
3267
3268 if (interruptible) {
3269 jlong prevtime = javaTimeNanos();
3270
3271 for (;;) {
3272 if (os::is_interrupted(thread, true)) {
3273 return OS_INTRPT;
3274 }
3275
3276 jlong newtime = javaTimeNanos();
3277
3278 if (newtime - prevtime < 0) {
3279 // time moving backwards, should only happen if no monotonic clock
3280 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3281 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3282 } else {
3283 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3284 }
3285
3286 if(millis <= 0) {
3287 return OS_OK;
3288 }
3289
3290 prevtime = newtime;
3291
3292 {
3293 assert(thread->is_Java_thread(), "sanity check");
3294 JavaThread *jt = (JavaThread *) thread;
3295 ThreadBlockInVM tbivm(jt);
3296 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3297
3298 jt->set_suspend_equivalent();
3299 // cleared by handle_special_suspend_equivalent_condition() or
3300 // java_suspend_self() via check_and_wait_while_suspended()
3301
3302 slp->park(millis);
3303
3304 // were we externally suspended while we were waiting?
3305 jt->check_and_wait_while_suspended();
3306 }
3307 }
3308 } else {
3309 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3310 jlong prevtime = javaTimeNanos();
3311
3312 for (;;) {
3313 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3314 // the 1st iteration ...
3315 jlong newtime = javaTimeNanos();
3316
3317 if (newtime - prevtime < 0) {
3318 // time moving backwards, should only happen if no monotonic clock
3319 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3320 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3321 } else {
3322 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3323 }
3324
3325 if(millis <= 0) break ;
3326
3327 prevtime = newtime;
3328 slp->park(millis);
3329 }
3330 return OS_OK ;
3331 }
3332 }
3333
3334 int os::naked_sleep() {
3335 // %% make the sleep time an integer flag. for now use 1 millisec.
3336 return os::sleep(Thread::current(), 1, false);
3337 }
3338
3339 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3340 void os::infinite_sleep() {
3341 while (true) { // sleep forever ...
3342 ::sleep(100); // ... 100 seconds at a time
3343 }
3344 }
3345
3346 // Used to convert frequent JVM_Yield() to nops
3347 bool os::dont_yield() {
3348 return DontYieldALot;
3349 }
3350
3351 void os::yield() {
3352 sched_yield();
3353 }
3354
3355 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3356
3357 void os::yield_all(int attempts) {
3358 // Yields to all threads, including threads with lower priorities
3359 // Threads on Linux are all with same priority. The Solaris style
3360 // os::yield_all() with nanosleep(1ms) is not necessary.
3361 sched_yield();
3362 }
3363
3364 // Called from the tight loops to possibly influence time-sharing heuristics
3365 void os::loop_breaker(int attempts) {
3366 os::yield_all(attempts);
3367 }
3368
3369 ////////////////////////////////////////////////////////////////////////////////
3370 // thread priority support
3371
3372 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3373 // only supports dynamic priority, static priority must be zero. For real-time
3374 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3375 // However, for large multi-threaded applications, SCHED_RR is not only slower
3376 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3377 // of 5 runs - Sep 2005).
3378 //
3379 // The following code actually changes the niceness of kernel-thread/LWP. It
3380 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3381 // not the entire user process, and user level threads are 1:1 mapped to kernel
3382 // threads. It has always been the case, but could change in the future. For
3383 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3384 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3385
3386 int os::java_to_os_priority[MaxPriority + 1] = {
3387 19, // 0 Entry should never be used
3388
3389 4, // 1 MinPriority
3390 3, // 2
3391 2, // 3
3392
3393 1, // 4
3394 0, // 5 NormPriority
3395 -1, // 6
3396
3397 -2, // 7
3398 -3, // 8
3399 -4, // 9 NearMaxPriority
3400
3401 -5 // 10 MaxPriority
3402 };
3403
3404 static int prio_init() {
3405 if (ThreadPriorityPolicy == 1) {
3406 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3407 // if effective uid is not root. Perhaps, a more elegant way of doing
3408 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3409 if (geteuid() != 0) {
3410 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3411 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3412 }
3413 ThreadPriorityPolicy = 0;
3414 }
3415 }
3416 return 0;
3417 }
3418
3419 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3420 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3421
3422 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3423 return (ret == 0) ? OS_OK : OS_ERR;
3424 }
3425
3426 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3427 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3428 *priority_ptr = java_to_os_priority[NormPriority];
3429 return OS_OK;
3430 }
3431
3432 errno = 0;
3433 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3434 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3435 }
3436
3437 // Hint to the underlying OS that a task switch would not be good.
3438 // Void return because it's a hint and can fail.
3439 void os::hint_no_preempt() {}
3440
3441 ////////////////////////////////////////////////////////////////////////////////
3442 // suspend/resume support
3443
3444 // the low-level signal-based suspend/resume support is a remnant from the
3445 // old VM-suspension that used to be for java-suspension, safepoints etc,
3446 // within hotspot. Now there is a single use-case for this:
3447 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3448 // that runs in the watcher thread.
3449 // The remaining code is greatly simplified from the more general suspension
3450 // code that used to be used.
3451 //
3452 // The protocol is quite simple:
3453 // - suspend:
3454 // - sends a signal to the target thread
3455 // - polls the suspend state of the osthread using a yield loop
3456 // - target thread signal handler (SR_handler) sets suspend state
3457 // and blocks in sigsuspend until continued
3458 // - resume:
3459 // - sets target osthread state to continue
3460 // - sends signal to end the sigsuspend loop in the SR_handler
3461 //
3462 // Note that the SR_lock plays no role in this suspend/resume protocol.
3463 //
3464
3465 static void resume_clear_context(OSThread *osthread) {
3466 osthread->set_ucontext(NULL);
3467 osthread->set_siginfo(NULL);
3468
3469 // notify the suspend action is completed, we have now resumed
3470 osthread->sr.clear_suspended();
3471 }
3472
3473 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3474 osthread->set_ucontext(context);
3475 osthread->set_siginfo(siginfo);
3476 }
3477
3478 //
3479 // Handler function invoked when a thread's execution is suspended or
3480 // resumed. We have to be careful that only async-safe functions are
3481 // called here (Note: most pthread functions are not async safe and
3482 // should be avoided.)
3483 //
3484 // Note: sigwait() is a more natural fit than sigsuspend() from an
3485 // interface point of view, but sigwait() prevents the signal hander
3486 // from being run. libpthread would get very confused by not having
3487 // its signal handlers run and prevents sigwait()'s use with the
3488 // mutex granting granting signal.
3489 //
3490 // Currently only ever called on the VMThread
3491 //
3492 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3493 // Save and restore errno to avoid confusing native code with EINTR
3494 // after sigsuspend.
3495 int old_errno = errno;
3496
3497 Thread* thread = Thread::current();
3498 OSThread* osthread = thread->osthread();
3499 assert(thread->is_VM_thread(), "Must be VMThread");
3500 // read current suspend action
3501 int action = osthread->sr.suspend_action();
3502 if (action == SR_SUSPEND) {
3503 suspend_save_context(osthread, siginfo, context);
3504
3505 // Notify the suspend action is about to be completed. do_suspend()
3506 // waits until SR_SUSPENDED is set and then returns. We will wait
3507 // here for a resume signal and that completes the suspend-other
3508 // action. do_suspend/do_resume is always called as a pair from
3509 // the same thread - so there are no races
3510
3511 // notify the caller
3512 osthread->sr.set_suspended();
3513
3514 sigset_t suspend_set; // signals for sigsuspend()
3515
3516 // get current set of blocked signals and unblock resume signal
3517 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3518 sigdelset(&suspend_set, SR_signum);
3519
3520 // wait here until we are resumed
3521 do {
3522 sigsuspend(&suspend_set);
3523 // ignore all returns until we get a resume signal
3524 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3525
3526 resume_clear_context(osthread);
3527
3528 } else {
3529 assert(action == SR_CONTINUE, "unexpected sr action");
3530 // nothing special to do - just leave the handler
3531 }
3532
3533 errno = old_errno;
3534 }
3535
3536
3537 static int SR_initialize() {
3538 struct sigaction act;
3539 char *s;
3540 /* Get signal number to use for suspend/resume */
3541 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3542 int sig = ::strtol(s, 0, 10);
3543 if (sig > 0 || sig < _NSIG) {
3544 SR_signum = sig;
3545 }
3546 }
3547
3548 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3549 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3550
3551 sigemptyset(&SR_sigset);
3552 sigaddset(&SR_sigset, SR_signum);
3553
3554 /* Set up signal handler for suspend/resume */
3555 act.sa_flags = SA_RESTART|SA_SIGINFO;
3556 act.sa_handler = (void (*)(int)) SR_handler;
3557
3558 // SR_signum is blocked by default.
3559 // 4528190 - We also need to block pthread restart signal (32 on all
3560 // supported Linux platforms). Note that LinuxThreads need to block
3561 // this signal for all threads to work properly. So we don't have
3562 // to use hard-coded signal number when setting up the mask.
3563 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3564
3565 if (sigaction(SR_signum, &act, 0) == -1) {
3566 return -1;
3567 }
3568
3569 // Save signal flag
3570 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3571 return 0;
3572 }
3573
3574 static int SR_finalize() {
3575 return 0;
3576 }
3577
3578
3579 // returns true on success and false on error - really an error is fatal
3580 // but this seems the normal response to library errors
3581 static bool do_suspend(OSThread* osthread) {
3582 // mark as suspended and send signal
3583 osthread->sr.set_suspend_action(SR_SUSPEND);
3584 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3585 assert_status(status == 0, status, "pthread_kill");
3586
3587 // check status and wait until notified of suspension
3588 if (status == 0) {
3589 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3590 os::yield_all(i);
3591 }
3592 osthread->sr.set_suspend_action(SR_NONE);
3593 return true;
3594 }
3595 else {
3596 osthread->sr.set_suspend_action(SR_NONE);
3597 return false;
3598 }
3599 }
3600
3601 static void do_resume(OSThread* osthread) {
3602 assert(osthread->sr.is_suspended(), "thread should be suspended");
3603 osthread->sr.set_suspend_action(SR_CONTINUE);
3604
3605 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3606 assert_status(status == 0, status, "pthread_kill");
3607 // check status and wait unit notified of resumption
3608 if (status == 0) {
3609 for (int i = 0; osthread->sr.is_suspended(); i++) {
3610 os::yield_all(i);
3611 }
3612 }
3613 osthread->sr.set_suspend_action(SR_NONE);
3614 }
3615
3616 ////////////////////////////////////////////////////////////////////////////////
3617 // interrupt support
3618
3619 void os::interrupt(Thread* thread) {
3620 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3621 "possibility of dangling Thread pointer");
3622
3623 OSThread* osthread = thread->osthread();
3624
3625 if (!osthread->interrupted()) {
3626 osthread->set_interrupted(true);
3627 // More than one thread can get here with the same value of osthread,
3628 // resulting in multiple notifications. We do, however, want the store
3629 // to interrupted() to be visible to other threads before we execute unpark().
3630 OrderAccess::fence();
3631 ParkEvent * const slp = thread->_SleepEvent ;
3632 if (slp != NULL) slp->unpark() ;
3633 }
3634
3635 // For JSR166. Unpark even if interrupt status already was set
3636 if (thread->is_Java_thread())
3637 ((JavaThread*)thread)->parker()->unpark();
3638
3639 ParkEvent * ev = thread->_ParkEvent ;
3640 if (ev != NULL) ev->unpark() ;
3641
3642 }
3643
3644 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3645 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3646 "possibility of dangling Thread pointer");
3647
3648 OSThread* osthread = thread->osthread();
3649
3650 bool interrupted = osthread->interrupted();
3651
3652 if (interrupted && clear_interrupted) {
3653 osthread->set_interrupted(false);
3654 // consider thread->_SleepEvent->reset() ... optional optimization
3655 }
3656
3657 return interrupted;
3658 }
3659
3660 ///////////////////////////////////////////////////////////////////////////////////
3661 // signal handling (except suspend/resume)
3662
3663 // This routine may be used by user applications as a "hook" to catch signals.
3664 // The user-defined signal handler must pass unrecognized signals to this
3665 // routine, and if it returns true (non-zero), then the signal handler must
3666 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3667 // routine will never retun false (zero), but instead will execute a VM panic
3668 // routine kill the process.
3669 //
3670 // If this routine returns false, it is OK to call it again. This allows
3671 // the user-defined signal handler to perform checks either before or after
3672 // the VM performs its own checks. Naturally, the user code would be making
3673 // a serious error if it tried to handle an exception (such as a null check
3674 // or breakpoint) that the VM was generating for its own correct operation.
3675 //
3676 // This routine may recognize any of the following kinds of signals:
3677 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3678 // It should be consulted by handlers for any of those signals.
3679 //
3680 // The caller of this routine must pass in the three arguments supplied
3681 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3682 // field of the structure passed to sigaction(). This routine assumes that
3683 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3684 //
3685 // Note that the VM will print warnings if it detects conflicting signal
3686 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3687 //
3688 extern "C" JNIEXPORT int
3689 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3690 void* ucontext, int abort_if_unrecognized);
3691
3692 void signalHandler(int sig, siginfo_t* info, void* uc) {
3693 assert(info != NULL && uc != NULL, "it must be old kernel");
3694 JVM_handle_linux_signal(sig, info, uc, true);
3695 }
3696
3697
3698 // This boolean allows users to forward their own non-matching signals
3699 // to JVM_handle_linux_signal, harmlessly.
3700 bool os::Linux::signal_handlers_are_installed = false;
3701
3702 // For signal-chaining
3703 struct sigaction os::Linux::sigact[MAXSIGNUM];
3704 unsigned int os::Linux::sigs = 0;
3705 bool os::Linux::libjsig_is_loaded = false;
3706 typedef struct sigaction *(*get_signal_t)(int);
3707 get_signal_t os::Linux::get_signal_action = NULL;
3708
3709 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3710 struct sigaction *actp = NULL;
3711
3712 if (libjsig_is_loaded) {
3713 // Retrieve the old signal handler from libjsig
3714 actp = (*get_signal_action)(sig);
3715 }
3716 if (actp == NULL) {
3717 // Retrieve the preinstalled signal handler from jvm
3718 actp = get_preinstalled_handler(sig);
3719 }
3720
3721 return actp;
3722 }
3723
3724 static bool call_chained_handler(struct sigaction *actp, int sig,
3725 siginfo_t *siginfo, void *context) {
3726 // Call the old signal handler
3727 if (actp->sa_handler == SIG_DFL) {
3728 // It's more reasonable to let jvm treat it as an unexpected exception
3729 // instead of taking the default action.
3730 return false;
3731 } else if (actp->sa_handler != SIG_IGN) {
3732 if ((actp->sa_flags & SA_NODEFER) == 0) {
3733 // automaticlly block the signal
3734 sigaddset(&(actp->sa_mask), sig);
3735 }
3736
3737 sa_handler_t hand;
3738 sa_sigaction_t sa;
3739 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3740 // retrieve the chained handler
3741 if (siginfo_flag_set) {
3742 sa = actp->sa_sigaction;
3743 } else {
3744 hand = actp->sa_handler;
3745 }
3746
3747 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3748 actp->sa_handler = SIG_DFL;
3749 }
3750
3751 // try to honor the signal mask
3752 sigset_t oset;
3753 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3754
3755 // call into the chained handler
3756 if (siginfo_flag_set) {
3757 (*sa)(sig, siginfo, context);
3758 } else {
3759 (*hand)(sig);
3760 }
3761
3762 // restore the signal mask
3763 pthread_sigmask(SIG_SETMASK, &oset, 0);
3764 }
3765 // Tell jvm's signal handler the signal is taken care of.
3766 return true;
3767 }
3768
3769 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3770 bool chained = false;
3771 // signal-chaining
3772 if (UseSignalChaining) {
3773 struct sigaction *actp = get_chained_signal_action(sig);
3774 if (actp != NULL) {
3775 chained = call_chained_handler(actp, sig, siginfo, context);
3776 }
3777 }
3778 return chained;
3779 }
3780
3781 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3782 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3783 return &sigact[sig];
3784 }
3785 return NULL;
3786 }
3787
3788 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3789 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3790 sigact[sig] = oldAct;
3791 sigs |= (unsigned int)1 << sig;
3792 }
3793
3794 // for diagnostic
3795 int os::Linux::sigflags[MAXSIGNUM];
3796
3797 int os::Linux::get_our_sigflags(int sig) {
3798 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3799 return sigflags[sig];
3800 }
3801
3802 void os::Linux::set_our_sigflags(int sig, int flags) {
3803 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3804 sigflags[sig] = flags;
3805 }
3806
3807 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3808 // Check for overwrite.
3809 struct sigaction oldAct;
3810 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3811
3812 void* oldhand = oldAct.sa_sigaction
3813 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3814 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3815 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3816 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3817 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3818 if (AllowUserSignalHandlers || !set_installed) {
3819 // Do not overwrite; user takes responsibility to forward to us.
3820 return;
3821 } else if (UseSignalChaining) {
3822 // save the old handler in jvm
3823 save_preinstalled_handler(sig, oldAct);
3824 // libjsig also interposes the sigaction() call below and saves the
3825 // old sigaction on it own.
3826 } else {
3827 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3828 "%#lx for signal %d.", (long)oldhand, sig));
3829 }
3830 }
3831
3832 struct sigaction sigAct;
3833 sigfillset(&(sigAct.sa_mask));
3834 sigAct.sa_handler = SIG_DFL;
3835 if (!set_installed) {
3836 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3837 } else {
3838 sigAct.sa_sigaction = signalHandler;
3839 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3840 }
3841 // Save flags, which are set by ours
3842 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3843 sigflags[sig] = sigAct.sa_flags;
3844
3845 int ret = sigaction(sig, &sigAct, &oldAct);
3846 assert(ret == 0, "check");
3847
3848 void* oldhand2 = oldAct.sa_sigaction
3849 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3850 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3851 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3852 }
3853
3854 // install signal handlers for signals that HotSpot needs to
3855 // handle in order to support Java-level exception handling.
3856
3857 void os::Linux::install_signal_handlers() {
3858 if (!signal_handlers_are_installed) {
3859 signal_handlers_are_installed = true;
3860
3861 // signal-chaining
3862 typedef void (*signal_setting_t)();
3863 signal_setting_t begin_signal_setting = NULL;
3864 signal_setting_t end_signal_setting = NULL;
3865 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3866 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3867 if (begin_signal_setting != NULL) {
3868 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3869 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3870 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3871 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3872 libjsig_is_loaded = true;
3873 assert(UseSignalChaining, "should enable signal-chaining");
3874 }
3875 if (libjsig_is_loaded) {
3876 // Tell libjsig jvm is setting signal handlers
3877 (*begin_signal_setting)();
3878 }
3879
3880 set_signal_handler(SIGSEGV, true);
3881 set_signal_handler(SIGPIPE, true);
3882 set_signal_handler(SIGBUS, true);
3883 set_signal_handler(SIGILL, true);
3884 set_signal_handler(SIGFPE, true);
3885 set_signal_handler(SIGXFSZ, true);
3886
3887 if (libjsig_is_loaded) {
3888 // Tell libjsig jvm finishes setting signal handlers
3889 (*end_signal_setting)();
3890 }
3891
3892 // We don't activate signal checker if libjsig is in place, we trust ourselves
3893 // and if UserSignalHandler is installed all bets are off.
3894 // Log that signal checking is off only if -verbose:jni is specified.
3895 if (CheckJNICalls) {
3896 if (libjsig_is_loaded) {
3897 if (PrintJNIResolving) {
3898 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3899 }
3900 check_signals = false;
3901 }
3902 if (AllowUserSignalHandlers) {
3903 if (PrintJNIResolving) {
3904 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3905 }
3906 check_signals = false;
3907 }
3908 }
3909 }
3910 }
3911
3912 // This is the fastest way to get thread cpu time on Linux.
3913 // Returns cpu time (user+sys) for any thread, not only for current.
3914 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3915 // It might work on 2.6.10+ with a special kernel/glibc patch.
3916 // For reference, please, see IEEE Std 1003.1-2004:
3917 // http://www.unix.org/single_unix_specification
3918
3919 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3920 struct timespec tp;
3921 int rc = os::Linux::clock_gettime(clockid, &tp);
3922 assert(rc == 0, "clock_gettime is expected to return 0 code");
3923
3924 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
3925 }
3926
3927 /////
3928 // glibc on Linux platform uses non-documented flag
3929 // to indicate, that some special sort of signal
3930 // trampoline is used.
3931 // We will never set this flag, and we should
3932 // ignore this flag in our diagnostic
3933 #ifdef SIGNIFICANT_SIGNAL_MASK
3934 #undef SIGNIFICANT_SIGNAL_MASK
3935 #endif
3936 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3937
3938 static const char* get_signal_handler_name(address handler,
3939 char* buf, int buflen) {
3940 int offset;
3941 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3942 if (found) {
3943 // skip directory names
3944 const char *p1, *p2;
3945 p1 = buf;
3946 size_t len = strlen(os::file_separator());
3947 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3948 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3949 } else {
3950 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3951 }
3952 return buf;
3953 }
3954
3955 static void print_signal_handler(outputStream* st, int sig,
3956 char* buf, size_t buflen) {
3957 struct sigaction sa;
3958
3959 sigaction(sig, NULL, &sa);
3960
3961 // See comment for SIGNIFICANT_SIGNAL_MASK define
3962 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3963
3964 st->print("%s: ", os::exception_name(sig, buf, buflen));
3965
3966 address handler = (sa.sa_flags & SA_SIGINFO)
3967 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3968 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3969
3970 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3971 st->print("SIG_DFL");
3972 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3973 st->print("SIG_IGN");
3974 } else {
3975 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3976 }
3977
3978 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3979
3980 address rh = VMError::get_resetted_sighandler(sig);
3981 // May be, handler was resetted by VMError?
3982 if(rh != NULL) {
3983 handler = rh;
3984 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3985 }
3986
3987 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3988
3989 // Check: is it our handler?
3990 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3991 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3992 // It is our signal handler
3993 // check for flags, reset system-used one!
3994 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3995 st->print(
3996 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3997 os::Linux::get_our_sigflags(sig));
3998 }
3999 }
4000 st->cr();
4001 }
4002
4003
4004 #define DO_SIGNAL_CHECK(sig) \
4005 if (!sigismember(&check_signal_done, sig)) \
4006 os::Linux::check_signal_handler(sig)
4007
4008 // This method is a periodic task to check for misbehaving JNI applications
4009 // under CheckJNI, we can add any periodic checks here
4010
4011 void os::run_periodic_checks() {
4012
4013 if (check_signals == false) return;
4014
4015 // SEGV and BUS if overridden could potentially prevent
4016 // generation of hs*.log in the event of a crash, debugging
4017 // such a case can be very challenging, so we absolutely
4018 // check the following for a good measure:
4019 DO_SIGNAL_CHECK(SIGSEGV);
4020 DO_SIGNAL_CHECK(SIGILL);
4021 DO_SIGNAL_CHECK(SIGFPE);
4022 DO_SIGNAL_CHECK(SIGBUS);
4023 DO_SIGNAL_CHECK(SIGPIPE);
4024 DO_SIGNAL_CHECK(SIGXFSZ);
4025
4026
4027 // ReduceSignalUsage allows the user to override these handlers
4028 // see comments at the very top and jvm_solaris.h
4029 if (!ReduceSignalUsage) {
4030 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4031 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4032 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4033 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4034 }
4035
4036 DO_SIGNAL_CHECK(SR_signum);
4037 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4038 }
4039
4040 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4041
4042 static os_sigaction_t os_sigaction = NULL;
4043
4044 void os::Linux::check_signal_handler(int sig) {
4045 char buf[O_BUFLEN];
4046 address jvmHandler = NULL;
4047
4048
4049 struct sigaction act;
4050 if (os_sigaction == NULL) {
4051 // only trust the default sigaction, in case it has been interposed
4052 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4053 if (os_sigaction == NULL) return;
4054 }
4055
4056 os_sigaction(sig, (struct sigaction*)NULL, &act);
4057
4058
4059 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4060
4061 address thisHandler = (act.sa_flags & SA_SIGINFO)
4062 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4063 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4064
4065
4066 switch(sig) {
4067 case SIGSEGV:
4068 case SIGBUS:
4069 case SIGFPE:
4070 case SIGPIPE:
4071 case SIGILL:
4072 case SIGXFSZ:
4073 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4074 break;
4075
4076 case SHUTDOWN1_SIGNAL:
4077 case SHUTDOWN2_SIGNAL:
4078 case SHUTDOWN3_SIGNAL:
4079 case BREAK_SIGNAL:
4080 jvmHandler = (address)user_handler();
4081 break;
4082
4083 case INTERRUPT_SIGNAL:
4084 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4085 break;
4086
4087 default:
4088 if (sig == SR_signum) {
4089 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4090 } else {
4091 return;
4092 }
4093 break;
4094 }
4095
4096 if (thisHandler != jvmHandler) {
4097 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4098 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4099 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4100 // No need to check this sig any longer
4101 sigaddset(&check_signal_done, sig);
4102 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4103 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4104 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4105 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4106 // No need to check this sig any longer
4107 sigaddset(&check_signal_done, sig);
4108 }
4109
4110 // Dump all the signal
4111 if (sigismember(&check_signal_done, sig)) {
4112 print_signal_handlers(tty, buf, O_BUFLEN);
4113 }
4114 }
4115
4116 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4117
4118 extern bool signal_name(int signo, char* buf, size_t len);
4119
4120 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4121 if (0 < exception_code && exception_code <= SIGRTMAX) {
4122 // signal
4123 if (!signal_name(exception_code, buf, size)) {
4124 jio_snprintf(buf, size, "SIG%d", exception_code);
4125 }
4126 return buf;
4127 } else {
4128 return NULL;
4129 }
4130 }
4131
4132 // this is called _before_ the most of global arguments have been parsed
4133 void os::init(void) {
4134 char dummy; /* used to get a guess on initial stack address */
4135 // first_hrtime = gethrtime();
4136
4137 // With LinuxThreads the JavaMain thread pid (primordial thread)
4138 // is different than the pid of the java launcher thread.
4139 // So, on Linux, the launcher thread pid is passed to the VM
4140 // via the sun.java.launcher.pid property.
4141 // Use this property instead of getpid() if it was correctly passed.
4142 // See bug 6351349.
4143 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4144
4145 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4146
4147 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4148
4149 init_random(1234567);
4150
4151 ThreadCritical::initialize();
4152
4153 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4154 if (Linux::page_size() == -1) {
4155 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4156 strerror(errno)));
4157 }
4158 init_page_sizes((size_t) Linux::page_size());
4159
4160 Linux::initialize_system_info();
4161
4162 // main_thread points to the aboriginal thread
4163 Linux::_main_thread = pthread_self();
4164
4165 Linux::clock_init();
4166 initial_time_count = os::elapsed_counter();
4167 pthread_mutex_init(&dl_mutex, NULL);
4168 }
4169
4170 // To install functions for atexit system call
4171 extern "C" {
4172 static void perfMemory_exit_helper() {
4173 perfMemory_exit();
4174 }
4175 }
4176
4177 // this is called _after_ the global arguments have been parsed
4178 jint os::init_2(void)
4179 {
4180 Linux::fast_thread_clock_init();
4181
4182 // Allocate a single page and mark it as readable for safepoint polling
4183 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4184 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4185
4186 os::set_polling_page( polling_page );
4187
4188 #ifndef PRODUCT
4189 if(Verbose && PrintMiscellaneous)
4190 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4191 #endif
4192
4193 if (!UseMembar) {
4194 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4195 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4196 os::set_memory_serialize_page( mem_serialize_page );
4197
4198 #ifndef PRODUCT
4199 if(Verbose && PrintMiscellaneous)
4200 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4201 #endif
4202 }
4203
4204 os::large_page_init();
4205
4206 // initialize suspend/resume support - must do this before signal_sets_init()
4207 if (SR_initialize() != 0) {
4208 perror("SR_initialize failed");
4209 return JNI_ERR;
4210 }
4211
4212 Linux::signal_sets_init();
4213 Linux::install_signal_handlers();
4214
4215 // Check minimum allowable stack size for thread creation and to initialize
4216 // the java system classes, including StackOverflowError - depends on page
4217 // size. Add a page for compiler2 recursion in main thread.
4218 // Add in 2*BytesPerWord times page size to account for VM stack during
4219 // class initialization depending on 32 or 64 bit VM.
4220 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4221 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4222 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4223
4224 size_t threadStackSizeInBytes = ThreadStackSize * K;
4225 if (threadStackSizeInBytes != 0 &&
4226 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4227 tty->print_cr("\nThe stack size specified is too small, "
4228 "Specify at least %dk",
4229 os::Linux::min_stack_allowed/ K);
4230 return JNI_ERR;
4231 }
4232
4233 // Make the stack size a multiple of the page size so that
4234 // the yellow/red zones can be guarded.
4235 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4236 vm_page_size()));
4237
4238 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4239
4240 Linux::libpthread_init();
4241 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4242 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4243 Linux::glibc_version(), Linux::libpthread_version(),
4244 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4245 }
4246
4247 if (UseNUMA) {
4248 if (!Linux::libnuma_init()) {
4249 UseNUMA = false;
4250 } else {
4251 if ((Linux::numa_max_node() < 1)) {
4252 // There's only one node(they start from 0), disable NUMA.
4253 UseNUMA = false;
4254 }
4255 }
4256 // With SHM large pages we cannot uncommit a page, so there's not way
4257 // we can make the adaptive lgrp chunk resizing work. If the user specified
4258 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4259 // disable adaptive resizing.
4260 if (UseNUMA && UseLargePages && UseSHM) {
4261 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4262 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4263 UseLargePages = false;
4264 } else {
4265 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4266 UseAdaptiveSizePolicy = false;
4267 UseAdaptiveNUMAChunkSizing = false;
4268 }
4269 } else {
4270 UseNUMA = false;
4271 }
4272 }
4273 if (!UseNUMA && ForceNUMA) {
4274 UseNUMA = true;
4275 }
4276 }
4277
4278 if (MaxFDLimit) {
4279 // set the number of file descriptors to max. print out error
4280 // if getrlimit/setrlimit fails but continue regardless.
4281 struct rlimit nbr_files;
4282 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4283 if (status != 0) {
4284 if (PrintMiscellaneous && (Verbose || WizardMode))
4285 perror("os::init_2 getrlimit failed");
4286 } else {
4287 nbr_files.rlim_cur = nbr_files.rlim_max;
4288 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4289 if (status != 0) {
4290 if (PrintMiscellaneous && (Verbose || WizardMode))
4291 perror("os::init_2 setrlimit failed");
4292 }
4293 }
4294 }
4295
4296 // Initialize lock used to serialize thread creation (see os::create_thread)
4297 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4298
4299 // at-exit methods are called in the reverse order of their registration.
4300 // atexit functions are called on return from main or as a result of a
4301 // call to exit(3C). There can be only 32 of these functions registered
4302 // and atexit() does not set errno.
4303
4304 if (PerfAllowAtExitRegistration) {
4305 // only register atexit functions if PerfAllowAtExitRegistration is set.
4306 // atexit functions can be delayed until process exit time, which
4307 // can be problematic for embedded VM situations. Embedded VMs should
4308 // call DestroyJavaVM() to assure that VM resources are released.
4309
4310 // note: perfMemory_exit_helper atexit function may be removed in
4311 // the future if the appropriate cleanup code can be added to the
4312 // VM_Exit VMOperation's doit method.
4313 if (atexit(perfMemory_exit_helper) != 0) {
4314 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4315 }
4316 }
4317
4318 // initialize thread priority policy
4319 prio_init();
4320
4321 return JNI_OK;
4322 }
4323
4324 // this is called at the end of vm_initialization
4325 void os::init_3(void)
4326 {
4327 #ifdef JAVASE_EMBEDDED
4328 // Start the MemNotifyThread
4329 if (LowMemoryProtection) {
4330 MemNotifyThread::start();
4331 }
4332 return;
4333 #endif
4334 }
4335
4336 // Mark the polling page as unreadable
4337 void os::make_polling_page_unreadable(void) {
4338 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4339 fatal("Could not disable polling page");
4340 };
4341
4342 // Mark the polling page as readable
4343 void os::make_polling_page_readable(void) {
4344 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4345 fatal("Could not enable polling page");
4346 }
4347 };
4348
4349 int os::active_processor_count() {
4350 // Linux doesn't yet have a (official) notion of processor sets,
4351 // so just return the number of online processors.
4352 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4353 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4354 return online_cpus;
4355 }
4356
4357 void os::set_native_thread_name(const char *name) {
4358 // Not yet implemented.
4359 return;
4360 }
4361
4362 bool os::distribute_processes(uint length, uint* distribution) {
4363 // Not yet implemented.
4364 return false;
4365 }
4366
4367 bool os::bind_to_processor(uint processor_id) {
4368 // Not yet implemented.
4369 return false;
4370 }
4371
4372 ///
4373
4374 // Suspends the target using the signal mechanism and then grabs the PC before
4375 // resuming the target. Used by the flat-profiler only
4376 ExtendedPC os::get_thread_pc(Thread* thread) {
4377 // Make sure that it is called by the watcher for the VMThread
4378 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4379 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4380
4381 ExtendedPC epc;
4382
4383 OSThread* osthread = thread->osthread();
4384 if (do_suspend(osthread)) {
4385 if (osthread->ucontext() != NULL) {
4386 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4387 } else {
4388 // NULL context is unexpected, double-check this is the VMThread
4389 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4390 }
4391 do_resume(osthread);
4392 }
4393 // failure means pthread_kill failed for some reason - arguably this is
4394 // a fatal problem, but such problems are ignored elsewhere
4395
4396 return epc;
4397 }
4398
4399 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4400 {
4401 if (is_NPTL()) {
4402 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4403 } else {
4404 #ifndef IA64
4405 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4406 // word back to default 64bit precision if condvar is signaled. Java
4407 // wants 53bit precision. Save and restore current value.
4408 int fpu = get_fpu_control_word();
4409 #endif // IA64
4410 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4411 #ifndef IA64
4412 set_fpu_control_word(fpu);
4413 #endif // IA64
4414 return status;
4415 }
4416 }
4417
4418 ////////////////////////////////////////////////////////////////////////////////
4419 // debug support
4420
4421 static address same_page(address x, address y) {
4422 int page_bits = -os::vm_page_size();
4423 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4424 return x;
4425 else if (x > y)
4426 return (address)(intptr_t(y) | ~page_bits) + 1;
4427 else
4428 return (address)(intptr_t(y) & page_bits);
4429 }
4430
4431 bool os::find(address addr, outputStream* st) {
4432 Dl_info dlinfo;
4433 memset(&dlinfo, 0, sizeof(dlinfo));
4434 if (dladdr(addr, &dlinfo)) {
4435 st->print(PTR_FORMAT ": ", addr);
4436 if (dlinfo.dli_sname != NULL) {
4437 st->print("%s+%#x", dlinfo.dli_sname,
4438 addr - (intptr_t)dlinfo.dli_saddr);
4439 } else if (dlinfo.dli_fname) {
4440 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4441 } else {
4442 st->print("<absolute address>");
4443 }
4444 if (dlinfo.dli_fname) {
4445 st->print(" in %s", dlinfo.dli_fname);
4446 }
4447 if (dlinfo.dli_fbase) {
4448 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4449 }
4450 st->cr();
4451
4452 if (Verbose) {
4453 // decode some bytes around the PC
4454 address begin = same_page(addr-40, addr);
4455 address end = same_page(addr+40, addr);
4456 address lowest = (address) dlinfo.dli_sname;
4457 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4458 if (begin < lowest) begin = lowest;
4459 Dl_info dlinfo2;
4460 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4461 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4462 end = (address) dlinfo2.dli_saddr;
4463 Disassembler::decode(begin, end, st);
4464 }
4465 return true;
4466 }
4467 return false;
4468 }
4469
4470 ////////////////////////////////////////////////////////////////////////////////
4471 // misc
4472
4473 // This does not do anything on Linux. This is basically a hook for being
4474 // able to use structured exception handling (thread-local exception filters)
4475 // on, e.g., Win32.
4476 void
4477 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4478 JavaCallArguments* args, Thread* thread) {
4479 f(value, method, args, thread);
4480 }
4481
4482 void os::print_statistics() {
4483 }
4484
4485 int os::message_box(const char* title, const char* message) {
4486 int i;
4487 fdStream err(defaultStream::error_fd());
4488 for (i = 0; i < 78; i++) err.print_raw("=");
4489 err.cr();
4490 err.print_raw_cr(title);
4491 for (i = 0; i < 78; i++) err.print_raw("-");
4492 err.cr();
4493 err.print_raw_cr(message);
4494 for (i = 0; i < 78; i++) err.print_raw("=");
4495 err.cr();
4496
4497 char buf[16];
4498 // Prevent process from exiting upon "read error" without consuming all CPU
4499 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4500
4501 return buf[0] == 'y' || buf[0] == 'Y';
4502 }
4503
4504 int os::stat(const char *path, struct stat *sbuf) {
4505 char pathbuf[MAX_PATH];
4506 if (strlen(path) > MAX_PATH - 1) {
4507 errno = ENAMETOOLONG;
4508 return -1;
4509 }
4510 os::native_path(strcpy(pathbuf, path));
4511 return ::stat(pathbuf, sbuf);
4512 }
4513
4514 bool os::check_heap(bool force) {
4515 return true;
4516 }
4517
4518 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4519 return ::vsnprintf(buf, count, format, args);
4520 }
4521
4522 // Is a (classpath) directory empty?
4523 bool os::dir_is_empty(const char* path) {
4524 DIR *dir = NULL;
4525 struct dirent *ptr;
4526
4527 dir = opendir(path);
4528 if (dir == NULL) return true;
4529
4530 /* Scan the directory */
4531 bool result = true;
4532 char buf[sizeof(struct dirent) + MAX_PATH];
4533 while (result && (ptr = ::readdir(dir)) != NULL) {
4534 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4535 result = false;
4536 }
4537 }
4538 closedir(dir);
4539 return result;
4540 }
4541
4542 // This code originates from JDK's sysOpen and open64_w
4543 // from src/solaris/hpi/src/system_md.c
4544
4545 #ifndef O_DELETE
4546 #define O_DELETE 0x10000
4547 #endif
4548
4549 // Open a file. Unlink the file immediately after open returns
4550 // if the specified oflag has the O_DELETE flag set.
4551 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4552
4553 int os::open(const char *path, int oflag, int mode) {
4554
4555 if (strlen(path) > MAX_PATH - 1) {
4556 errno = ENAMETOOLONG;
4557 return -1;
4558 }
4559 int fd;
4560 int o_delete = (oflag & O_DELETE);
4561 oflag = oflag & ~O_DELETE;
4562
4563 fd = ::open64(path, oflag, mode);
4564 if (fd == -1) return -1;
4565
4566 //If the open succeeded, the file might still be a directory
4567 {
4568 struct stat64 buf64;
4569 int ret = ::fstat64(fd, &buf64);
4570 int st_mode = buf64.st_mode;
4571
4572 if (ret != -1) {
4573 if ((st_mode & S_IFMT) == S_IFDIR) {
4574 errno = EISDIR;
4575 ::close(fd);
4576 return -1;
4577 }
4578 } else {
4579 ::close(fd);
4580 return -1;
4581 }
4582 }
4583
4584 /*
4585 * All file descriptors that are opened in the JVM and not
4586 * specifically destined for a subprocess should have the
4587 * close-on-exec flag set. If we don't set it, then careless 3rd
4588 * party native code might fork and exec without closing all
4589 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4590 * UNIXProcess.c), and this in turn might:
4591 *
4592 * - cause end-of-file to fail to be detected on some file
4593 * descriptors, resulting in mysterious hangs, or
4594 *
4595 * - might cause an fopen in the subprocess to fail on a system
4596 * suffering from bug 1085341.
4597 *
4598 * (Yes, the default setting of the close-on-exec flag is a Unix
4599 * design flaw)
4600 *
4601 * See:
4602 * 1085341: 32-bit stdio routines should support file descriptors >255
4603 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4604 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4605 */
4606 #ifdef FD_CLOEXEC
4607 {
4608 int flags = ::fcntl(fd, F_GETFD);
4609 if (flags != -1)
4610 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4611 }
4612 #endif
4613
4614 if (o_delete != 0) {
4615 ::unlink(path);
4616 }
4617 return fd;
4618 }
4619
4620
4621 // create binary file, rewriting existing file if required
4622 int os::create_binary_file(const char* path, bool rewrite_existing) {
4623 int oflags = O_WRONLY | O_CREAT;
4624 if (!rewrite_existing) {
4625 oflags |= O_EXCL;
4626 }
4627 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4628 }
4629
4630 // return current position of file pointer
4631 jlong os::current_file_offset(int fd) {
4632 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4633 }
4634
4635 // move file pointer to the specified offset
4636 jlong os::seek_to_file_offset(int fd, jlong offset) {
4637 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4638 }
4639
4640 // This code originates from JDK's sysAvailable
4641 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4642
4643 int os::available(int fd, jlong *bytes) {
4644 jlong cur, end;
4645 int mode;
4646 struct stat64 buf64;
4647
4648 if (::fstat64(fd, &buf64) >= 0) {
4649 mode = buf64.st_mode;
4650 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4651 /*
4652 * XXX: is the following call interruptible? If so, this might
4653 * need to go through the INTERRUPT_IO() wrapper as for other
4654 * blocking, interruptible calls in this file.
4655 */
4656 int n;
4657 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4658 *bytes = n;
4659 return 1;
4660 }
4661 }
4662 }
4663 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4664 return 0;
4665 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4666 return 0;
4667 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4668 return 0;
4669 }
4670 *bytes = end - cur;
4671 return 1;
4672 }
4673
4674 int os::socket_available(int fd, jint *pbytes) {
4675 // Linux doc says EINTR not returned, unlike Solaris
4676 int ret = ::ioctl(fd, FIONREAD, pbytes);
4677
4678 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4679 // is expected to return 0 on failure and 1 on success to the jdk.
4680 return (ret < 0) ? 0 : 1;
4681 }
4682
4683 // Map a block of memory.
4684 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4685 char *addr, size_t bytes, bool read_only,
4686 bool allow_exec) {
4687 int prot;
4688 int flags;
4689
4690 if (read_only) {
4691 prot = PROT_READ;
4692 flags = MAP_SHARED;
4693 } else {
4694 prot = PROT_READ | PROT_WRITE;
4695 flags = MAP_PRIVATE;
4696 }
4697
4698 if (allow_exec) {
4699 prot |= PROT_EXEC;
4700 }
4701
4702 if (addr != NULL) {
4703 flags |= MAP_FIXED;
4704 }
4705
4706 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4707 fd, file_offset);
4708 if (mapped_address == MAP_FAILED) {
4709 return NULL;
4710 }
4711 return mapped_address;
4712 }
4713
4714
4715 // Remap a block of memory.
4716 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4717 char *addr, size_t bytes, bool read_only,
4718 bool allow_exec) {
4719 // same as map_memory() on this OS
4720 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4721 allow_exec);
4722 }
4723
4724
4725 // Unmap a block of memory.
4726 bool os::unmap_memory(char* addr, size_t bytes) {
4727 return munmap(addr, bytes) == 0;
4728 }
4729
4730 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4731
4732 static clockid_t thread_cpu_clockid(Thread* thread) {
4733 pthread_t tid = thread->osthread()->pthread_id();
4734 clockid_t clockid;
4735
4736 // Get thread clockid
4737 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4738 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4739 return clockid;
4740 }
4741
4742 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4743 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4744 // of a thread.
4745 //
4746 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4747 // the fast estimate available on the platform.
4748
4749 jlong os::current_thread_cpu_time() {
4750 if (os::Linux::supports_fast_thread_cpu_time()) {
4751 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4752 } else {
4753 // return user + sys since the cost is the same
4754 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4755 }
4756 }
4757
4758 jlong os::thread_cpu_time(Thread* thread) {
4759 // consistent with what current_thread_cpu_time() returns
4760 if (os::Linux::supports_fast_thread_cpu_time()) {
4761 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4762 } else {
4763 return slow_thread_cpu_time(thread, true /* user + sys */);
4764 }
4765 }
4766
4767 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4768 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4769 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4770 } else {
4771 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4772 }
4773 }
4774
4775 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4776 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4777 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4778 } else {
4779 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4780 }
4781 }
4782
4783 //
4784 // -1 on error.
4785 //
4786
4787 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4788 static bool proc_pid_cpu_avail = true;
4789 static bool proc_task_unchecked = true;
4790 static const char *proc_stat_path = "/proc/%d/stat";
4791 pid_t tid = thread->osthread()->thread_id();
4792 int i;
4793 char *s;
4794 char stat[2048];
4795 int statlen;
4796 char proc_name[64];
4797 int count;
4798 long sys_time, user_time;
4799 char string[64];
4800 char cdummy;
4801 int idummy;
4802 long ldummy;
4803 FILE *fp;
4804
4805 // We first try accessing /proc/<pid>/cpu since this is faster to
4806 // process. If this file is not present (linux kernels 2.5 and above)
4807 // then we open /proc/<pid>/stat.
4808 if ( proc_pid_cpu_avail ) {
4809 sprintf(proc_name, "/proc/%d/cpu", tid);
4810 fp = fopen(proc_name, "r");
4811 if ( fp != NULL ) {
4812 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4813 fclose(fp);
4814 if ( count != 3 ) return -1;
4815
4816 if (user_sys_cpu_time) {
4817 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4818 } else {
4819 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4820 }
4821 }
4822 else proc_pid_cpu_avail = false;
4823 }
4824
4825 // The /proc/<tid>/stat aggregates per-process usage on
4826 // new Linux kernels 2.6+ where NPTL is supported.
4827 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4828 // See bug 6328462.
4829 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4830 // and possibly in some other cases, so we check its availability.
4831 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4832 // This is executed only once
4833 proc_task_unchecked = false;
4834 fp = fopen("/proc/self/task", "r");
4835 if (fp != NULL) {
4836 proc_stat_path = "/proc/self/task/%d/stat";
4837 fclose(fp);
4838 }
4839 }
4840
4841 sprintf(proc_name, proc_stat_path, tid);
4842 fp = fopen(proc_name, "r");
4843 if ( fp == NULL ) return -1;
4844 statlen = fread(stat, 1, 2047, fp);
4845 stat[statlen] = '\0';
4846 fclose(fp);
4847
4848 // Skip pid and the command string. Note that we could be dealing with
4849 // weird command names, e.g. user could decide to rename java launcher
4850 // to "java 1.4.2 :)", then the stat file would look like
4851 // 1234 (java 1.4.2 :)) R ... ...
4852 // We don't really need to know the command string, just find the last
4853 // occurrence of ")" and then start parsing from there. See bug 4726580.
4854 s = strrchr(stat, ')');
4855 i = 0;
4856 if (s == NULL ) return -1;
4857
4858 // Skip blank chars
4859 do s++; while (isspace(*s));
4860
4861 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4862 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4863 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4864 &user_time, &sys_time);
4865 if ( count != 13 ) return -1;
4866 if (user_sys_cpu_time) {
4867 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4868 } else {
4869 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4870 }
4871 }
4872
4873 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4874 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4875 info_ptr->may_skip_backward = false; // elapsed time not wall time
4876 info_ptr->may_skip_forward = false; // elapsed time not wall time
4877 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4878 }
4879
4880 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4881 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4882 info_ptr->may_skip_backward = false; // elapsed time not wall time
4883 info_ptr->may_skip_forward = false; // elapsed time not wall time
4884 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4885 }
4886
4887 bool os::is_thread_cpu_time_supported() {
4888 return true;
4889 }
4890
4891 // System loadavg support. Returns -1 if load average cannot be obtained.
4892 // Linux doesn't yet have a (official) notion of processor sets,
4893 // so just return the system wide load average.
4894 int os::loadavg(double loadavg[], int nelem) {
4895 return ::getloadavg(loadavg, nelem);
4896 }
4897
4898 void os::pause() {
4899 char filename[MAX_PATH];
4900 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4901 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4902 } else {
4903 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4904 }
4905
4906 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4907 if (fd != -1) {
4908 struct stat buf;
4909 ::close(fd);
4910 while (::stat(filename, &buf) == 0) {
4911 (void)::poll(NULL, 0, 100);
4912 }
4913 } else {
4914 jio_fprintf(stderr,
4915 "Could not open pause file '%s', continuing immediately.\n", filename);
4916 }
4917 }
4918
4919
4920 // Refer to the comments in os_solaris.cpp park-unpark.
4921 //
4922 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4923 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4924 // For specifics regarding the bug see GLIBC BUGID 261237 :
4925 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4926 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4927 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4928 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4929 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4930 // and monitorenter when we're using 1-0 locking. All those operations may result in
4931 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4932 // of libpthread avoids the problem, but isn't practical.
4933 //
4934 // Possible remedies:
4935 //
4936 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4937 // This is palliative and probabilistic, however. If the thread is preempted
4938 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4939 // than the minimum period may have passed, and the abstime may be stale (in the
4940 // past) resultin in a hang. Using this technique reduces the odds of a hang
4941 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4942 //
4943 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4944 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4945 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4946 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4947 // thread.
4948 //
4949 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4950 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4951 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4952 // This also works well. In fact it avoids kernel-level scalability impediments
4953 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4954 // timers in a graceful fashion.
4955 //
4956 // 4. When the abstime value is in the past it appears that control returns
4957 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4958 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4959 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4960 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4961 // It may be possible to avoid reinitialization by checking the return
4962 // value from pthread_cond_timedwait(). In addition to reinitializing the
4963 // condvar we must establish the invariant that cond_signal() is only called
4964 // within critical sections protected by the adjunct mutex. This prevents
4965 // cond_signal() from "seeing" a condvar that's in the midst of being
4966 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4967 // desirable signal-after-unlock optimization that avoids futile context switching.
4968 //
4969 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4970 // structure when a condvar is used or initialized. cond_destroy() would
4971 // release the helper structure. Our reinitialize-after-timedwait fix
4972 // put excessive stress on malloc/free and locks protecting the c-heap.
4973 //
4974 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4975 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4976 // and only enabling the work-around for vulnerable environments.
4977
4978 // utility to compute the abstime argument to timedwait:
4979 // millis is the relative timeout time
4980 // abstime will be the absolute timeout time
4981 // TODO: replace compute_abstime() with unpackTime()
4982
4983 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4984 if (millis < 0) millis = 0;
4985 struct timeval now;
4986 int status = gettimeofday(&now, NULL);
4987 assert(status == 0, "gettimeofday");
4988 jlong seconds = millis / 1000;
4989 millis %= 1000;
4990 if (seconds > 50000000) { // see man cond_timedwait(3T)
4991 seconds = 50000000;
4992 }
4993 abstime->tv_sec = now.tv_sec + seconds;
4994 long usec = now.tv_usec + millis * 1000;
4995 if (usec >= 1000000) {
4996 abstime->tv_sec += 1;
4997 usec -= 1000000;
4998 }
4999 abstime->tv_nsec = usec * 1000;
5000 return abstime;
5001 }
5002
5003
5004 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5005 // Conceptually TryPark() should be equivalent to park(0).
5006
5007 int os::PlatformEvent::TryPark() {
5008 for (;;) {
5009 const int v = _Event ;
5010 guarantee ((v == 0) || (v == 1), "invariant") ;
5011 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5012 }
5013 }
5014
5015 void os::PlatformEvent::park() { // AKA "down()"
5016 // Invariant: Only the thread associated with the Event/PlatformEvent
5017 // may call park().
5018 // TODO: assert that _Assoc != NULL or _Assoc == Self
5019 int v ;
5020 for (;;) {
5021 v = _Event ;
5022 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5023 }
5024 guarantee (v >= 0, "invariant") ;
5025 if (v == 0) {
5026 // Do this the hard way by blocking ...
5027 int status = pthread_mutex_lock(_mutex);
5028 assert_status(status == 0, status, "mutex_lock");
5029 guarantee (_nParked == 0, "invariant") ;
5030 ++ _nParked ;
5031 while (_Event < 0) {
5032 status = pthread_cond_wait(_cond, _mutex);
5033 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5034 // Treat this the same as if the wait was interrupted
5035 if (status == ETIME) { status = EINTR; }
5036 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5037 }
5038 -- _nParked ;
5039
5040 // In theory we could move the ST of 0 into _Event past the unlock(),
5041 // but then we'd need a MEMBAR after the ST.
5042 _Event = 0 ;
5043 status = pthread_mutex_unlock(_mutex);
5044 assert_status(status == 0, status, "mutex_unlock");
5045 }
5046 guarantee (_Event >= 0, "invariant") ;
5047 }
5048
5049 int os::PlatformEvent::park(jlong millis) {
5050 guarantee (_nParked == 0, "invariant") ;
5051
5052 int v ;
5053 for (;;) {
5054 v = _Event ;
5055 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5056 }
5057 guarantee (v >= 0, "invariant") ;
5058 if (v != 0) return OS_OK ;
5059
5060 // We do this the hard way, by blocking the thread.
5061 // Consider enforcing a minimum timeout value.
5062 struct timespec abst;
5063 compute_abstime(&abst, millis);
5064
5065 int ret = OS_TIMEOUT;
5066 int status = pthread_mutex_lock(_mutex);
5067 assert_status(status == 0, status, "mutex_lock");
5068 guarantee (_nParked == 0, "invariant") ;
5069 ++_nParked ;
5070
5071 // Object.wait(timo) will return because of
5072 // (a) notification
5073 // (b) timeout
5074 // (c) thread.interrupt
5075 //
5076 // Thread.interrupt and object.notify{All} both call Event::set.
5077 // That is, we treat thread.interrupt as a special case of notification.
5078 // The underlying Solaris implementation, cond_timedwait, admits
5079 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5080 // JVM from making those visible to Java code. As such, we must
5081 // filter out spurious wakeups. We assume all ETIME returns are valid.
5082 //
5083 // TODO: properly differentiate simultaneous notify+interrupt.
5084 // In that case, we should propagate the notify to another waiter.
5085
5086 while (_Event < 0) {
5087 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5088 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5089 pthread_cond_destroy (_cond);
5090 pthread_cond_init (_cond, NULL) ;
5091 }
5092 assert_status(status == 0 || status == EINTR ||
5093 status == ETIME || status == ETIMEDOUT,
5094 status, "cond_timedwait");
5095 if (!FilterSpuriousWakeups) break ; // previous semantics
5096 if (status == ETIME || status == ETIMEDOUT) break ;
5097 // We consume and ignore EINTR and spurious wakeups.
5098 }
5099 --_nParked ;
5100 if (_Event >= 0) {
5101 ret = OS_OK;
5102 }
5103 _Event = 0 ;
5104 status = pthread_mutex_unlock(_mutex);
5105 assert_status(status == 0, status, "mutex_unlock");
5106 assert (_nParked == 0, "invariant") ;
5107 return ret;
5108 }
5109
5110 void os::PlatformEvent::unpark() {
5111 int v, AnyWaiters ;
5112 for (;;) {
5113 v = _Event ;
5114 if (v > 0) {
5115 // The LD of _Event could have reordered or be satisfied
5116 // by a read-aside from this processor's write buffer.
5117 // To avoid problems execute a barrier and then
5118 // ratify the value.
5119 OrderAccess::fence() ;
5120 if (_Event == v) return ;
5121 continue ;
5122 }
5123 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5124 }
5125 if (v < 0) {
5126 // Wait for the thread associated with the event to vacate
5127 int status = pthread_mutex_lock(_mutex);
5128 assert_status(status == 0, status, "mutex_lock");
5129 AnyWaiters = _nParked ;
5130 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5131 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5132 AnyWaiters = 0 ;
5133 pthread_cond_signal (_cond);
5134 }
5135 status = pthread_mutex_unlock(_mutex);
5136 assert_status(status == 0, status, "mutex_unlock");
5137 if (AnyWaiters != 0) {
5138 status = pthread_cond_signal(_cond);
5139 assert_status(status == 0, status, "cond_signal");
5140 }
5141 }
5142
5143 // Note that we signal() _after dropping the lock for "immortal" Events.
5144 // This is safe and avoids a common class of futile wakeups. In rare
5145 // circumstances this can cause a thread to return prematurely from
5146 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5147 // simply re-test the condition and re-park itself.
5148 }
5149
5150
5151 // JSR166
5152 // -------------------------------------------------------
5153
5154 /*
5155 * The solaris and linux implementations of park/unpark are fairly
5156 * conservative for now, but can be improved. They currently use a
5157 * mutex/condvar pair, plus a a count.
5158 * Park decrements count if > 0, else does a condvar wait. Unpark
5159 * sets count to 1 and signals condvar. Only one thread ever waits
5160 * on the condvar. Contention seen when trying to park implies that someone
5161 * is unparking you, so don't wait. And spurious returns are fine, so there
5162 * is no need to track notifications.
5163 */
5164
5165 #define MAX_SECS 100000000
5166 /*
5167 * This code is common to linux and solaris and will be moved to a
5168 * common place in dolphin.
5169 *
5170 * The passed in time value is either a relative time in nanoseconds
5171 * or an absolute time in milliseconds. Either way it has to be unpacked
5172 * into suitable seconds and nanoseconds components and stored in the
5173 * given timespec structure.
5174 * Given time is a 64-bit value and the time_t used in the timespec is only
5175 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5176 * overflow if times way in the future are given. Further on Solaris versions
5177 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5178 * number of seconds, in abstime, is less than current_time + 100,000,000.
5179 * As it will be 28 years before "now + 100000000" will overflow we can
5180 * ignore overflow and just impose a hard-limit on seconds using the value
5181 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5182 * years from "now".
5183 */
5184
5185 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5186 assert (time > 0, "convertTime");
5187
5188 struct timeval now;
5189 int status = gettimeofday(&now, NULL);
5190 assert(status == 0, "gettimeofday");
5191
5192 time_t max_secs = now.tv_sec + MAX_SECS;
5193
5194 if (isAbsolute) {
5195 jlong secs = time / 1000;
5196 if (secs > max_secs) {
5197 absTime->tv_sec = max_secs;
5198 }
5199 else {
5200 absTime->tv_sec = secs;
5201 }
5202 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5203 }
5204 else {
5205 jlong secs = time / NANOSECS_PER_SEC;
5206 if (secs >= MAX_SECS) {
5207 absTime->tv_sec = max_secs;
5208 absTime->tv_nsec = 0;
5209 }
5210 else {
5211 absTime->tv_sec = now.tv_sec + secs;
5212 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5213 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5214 absTime->tv_nsec -= NANOSECS_PER_SEC;
5215 ++absTime->tv_sec; // note: this must be <= max_secs
5216 }
5217 }
5218 }
5219 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5220 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5221 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5222 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5223 }
5224
5225 void Parker::park(bool isAbsolute, jlong time) {
5226 // Optional fast-path check:
5227 // Return immediately if a permit is available.
5228 if (_counter > 0) {
5229 _counter = 0 ;
5230 OrderAccess::fence();
5231 return ;
5232 }
5233
5234 Thread* thread = Thread::current();
5235 assert(thread->is_Java_thread(), "Must be JavaThread");
5236 JavaThread *jt = (JavaThread *)thread;
5237
5238 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5239 // Check interrupt before trying to wait
5240 if (Thread::is_interrupted(thread, false)) {
5241 return;
5242 }
5243
5244 // Next, demultiplex/decode time arguments
5245 timespec absTime;
5246 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5247 return;
5248 }
5249 if (time > 0) {
5250 unpackTime(&absTime, isAbsolute, time);
5251 }
5252
5253
5254 // Enter safepoint region
5255 // Beware of deadlocks such as 6317397.
5256 // The per-thread Parker:: mutex is a classic leaf-lock.
5257 // In particular a thread must never block on the Threads_lock while
5258 // holding the Parker:: mutex. If safepoints are pending both the
5259 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5260 ThreadBlockInVM tbivm(jt);
5261
5262 // Don't wait if cannot get lock since interference arises from
5263 // unblocking. Also. check interrupt before trying wait
5264 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5265 return;
5266 }
5267
5268 int status ;
5269 if (_counter > 0) { // no wait needed
5270 _counter = 0;
5271 status = pthread_mutex_unlock(_mutex);
5272 assert (status == 0, "invariant") ;
5273 OrderAccess::fence();
5274 return;
5275 }
5276
5277 #ifdef ASSERT
5278 // Don't catch signals while blocked; let the running threads have the signals.
5279 // (This allows a debugger to break into the running thread.)
5280 sigset_t oldsigs;
5281 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5282 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5283 #endif
5284
5285 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5286 jt->set_suspend_equivalent();
5287 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5288
5289 if (time == 0) {
5290 status = pthread_cond_wait (_cond, _mutex) ;
5291 } else {
5292 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5293 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5294 pthread_cond_destroy (_cond) ;
5295 pthread_cond_init (_cond, NULL);
5296 }
5297 }
5298 assert_status(status == 0 || status == EINTR ||
5299 status == ETIME || status == ETIMEDOUT,
5300 status, "cond_timedwait");
5301
5302 #ifdef ASSERT
5303 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5304 #endif
5305
5306 _counter = 0 ;
5307 status = pthread_mutex_unlock(_mutex) ;
5308 assert_status(status == 0, status, "invariant") ;
5309 // If externally suspended while waiting, re-suspend
5310 if (jt->handle_special_suspend_equivalent_condition()) {
5311 jt->java_suspend_self();
5312 }
5313
5314 OrderAccess::fence();
5315 }
5316
5317 void Parker::unpark() {
5318 int s, status ;
5319 status = pthread_mutex_lock(_mutex);
5320 assert (status == 0, "invariant") ;
5321 s = _counter;
5322 _counter = 1;
5323 if (s < 1) {
5324 if (WorkAroundNPTLTimedWaitHang) {
5325 status = pthread_cond_signal (_cond) ;
5326 assert (status == 0, "invariant") ;
5327 status = pthread_mutex_unlock(_mutex);
5328 assert (status == 0, "invariant") ;
5329 } else {
5330 status = pthread_mutex_unlock(_mutex);
5331 assert (status == 0, "invariant") ;
5332 status = pthread_cond_signal (_cond) ;
5333 assert (status == 0, "invariant") ;
5334 }
5335 } else {
5336 pthread_mutex_unlock(_mutex);
5337 assert (status == 0, "invariant") ;
5338 }
5339 }
5340
5341
5342 extern char** environ;
5343
5344 #ifndef __NR_fork
5345 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5346 #endif
5347
5348 #ifndef __NR_execve
5349 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5350 #endif
5351
5352 // Run the specified command in a separate process. Return its exit value,
5353 // or -1 on failure (e.g. can't fork a new process).
5354 // Unlike system(), this function can be called from signal handler. It
5355 // doesn't block SIGINT et al.
5356 int os::fork_and_exec(char* cmd) {
5357 const char * argv[4] = {"sh", "-c", cmd, NULL};
5358
5359 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5360 // pthread_atfork handlers and reset pthread library. All we need is a
5361 // separate process to execve. Make a direct syscall to fork process.
5362 // On IA64 there's no fork syscall, we have to use fork() and hope for
5363 // the best...
5364 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5365 IA64_ONLY(fork();)
5366
5367 if (pid < 0) {
5368 // fork failed
5369 return -1;
5370
5371 } else if (pid == 0) {
5372 // child process
5373
5374 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5375 // first to kill every thread on the thread list. Because this list is
5376 // not reset by fork() (see notes above), execve() will instead kill
5377 // every thread in the parent process. We know this is the only thread
5378 // in the new process, so make a system call directly.
5379 // IA64 should use normal execve() from glibc to match the glibc fork()
5380 // above.
5381 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5382 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5383
5384 // execve failed
5385 _exit(-1);
5386
5387 } else {
5388 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5389 // care about the actual exit code, for now.
5390
5391 int status;
5392
5393 // Wait for the child process to exit. This returns immediately if
5394 // the child has already exited. */
5395 while (waitpid(pid, &status, 0) < 0) {
5396 switch (errno) {
5397 case ECHILD: return 0;
5398 case EINTR: break;
5399 default: return -1;
5400 }
5401 }
5402
5403 if (WIFEXITED(status)) {
5404 // The child exited normally; get its exit code.
5405 return WEXITSTATUS(status);
5406 } else if (WIFSIGNALED(status)) {
5407 // The child exited because of a signal
5408 // The best value to return is 0x80 + signal number,
5409 // because that is what all Unix shells do, and because
5410 // it allows callers to distinguish between process exit and
5411 // process death by signal.
5412 return 0x80 + WTERMSIG(status);
5413 } else {
5414 // Unknown exit code; pass it through
5415 return status;
5416 }
5417 }
5418 }
5419
5420 // is_headless_jre()
5421 //
5422 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5423 // in order to report if we are running in a headless jre
5424 //
5425 // Since JDK8 xawt/libmawt.so was moved into the same directory
5426 // as libawt.so, and renamed libawt_xawt.so
5427 //
5428 bool os::is_headless_jre() {
5429 struct stat statbuf;
5430 char buf[MAXPATHLEN];
5431 char libmawtpath[MAXPATHLEN];
5432 const char *xawtstr = "/xawt/libmawt.so";
5433 const char *new_xawtstr = "/libawt_xawt.so";
5434 char *p;
5435
5436 // Get path to libjvm.so
5437 os::jvm_path(buf, sizeof(buf));
5438
5439 // Get rid of libjvm.so
5440 p = strrchr(buf, '/');
5441 if (p == NULL) return false;
5442 else *p = '\0';
5443
5444 // Get rid of client or server
5445 p = strrchr(buf, '/');
5446 if (p == NULL) return false;
5447 else *p = '\0';
5448
5449 // check xawt/libmawt.so
5450 strcpy(libmawtpath, buf);
5451 strcat(libmawtpath, xawtstr);
5452 if (::stat(libmawtpath, &statbuf) == 0) return false;
5453
5454 // check libawt_xawt.so
5455 strcpy(libmawtpath, buf);
5456 strcat(libmawtpath, new_xawtstr);
5457 if (::stat(libmawtpath, &statbuf) == 0) return false;
5458
5459 return true;
5460 }
5461
5462
5463 #ifdef JAVASE_EMBEDDED
5464 //
5465 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5466 //
5467 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5468
5469 // ctor
5470 //
5471 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5472 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5473 _fd = fd;
5474
5475 if (os::create_thread(this, os::os_thread)) {
5476 _memnotify_thread = this;
5477 os::set_priority(this, NearMaxPriority);
5478 os::start_thread(this);
5479 }
5480 }
5481
5482 // Where all the work gets done
5483 //
5484 void MemNotifyThread::run() {
5485 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5486
5487 // Set up the select arguments
5488 fd_set rfds;
5489 if (_fd != -1) {
5490 FD_ZERO(&rfds);
5491 FD_SET(_fd, &rfds);
5492 }
5493
5494 // Now wait for the mem_notify device to wake up
5495 while (1) {
5496 // Wait for the mem_notify device to signal us..
5497 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5498 if (rc == -1) {
5499 perror("select!\n");
5500 break;
5501 } else if (rc) {
5502 //ssize_t free_before = os::available_memory();
5503 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5504
5505 // The kernel is telling us there is not much memory left...
5506 // try to do something about that
5507
5508 // If we are not already in a GC, try one.
5509 if (!Universe::heap()->is_gc_active()) {
5510 Universe::heap()->collect(GCCause::_allocation_failure);
5511
5512 //ssize_t free_after = os::available_memory();
5513 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5514 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5515 }
5516 // We might want to do something like the following if we find the GC's are not helping...
5517 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5518 }
5519 }
5520 }
5521
5522 //
5523 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5524 //
5525 void MemNotifyThread::start() {
5526 int fd;
5527 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5528 if (fd < 0) {
5529 return;
5530 }
5531
5532 if (memnotify_thread() == NULL) {
5533 new MemNotifyThread(fd);
5534 }
5535 }
5536 #endif // JAVASE_EMBEDDED