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 # define __STDC_FORMAT_MACROS
26
27 // no precompiled headers
28 #include "classfile/classLoader.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/icBuffer.hpp"
32 #include "code/vtableStubs.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "jvm_linux.h"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "mutex_linux.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_share_linux.hpp"
41 #include "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/extendedPC.hpp"
46 #include "runtime/globals.hpp"
47 #include "runtime/interfaceSupport.hpp"
48 #include "runtime/java.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/objectMonitor.hpp"
52 #include "runtime/osThread.hpp"
53 #include "runtime/perfMemory.hpp"
54 #include "runtime/sharedRuntime.hpp"
55 #include "runtime/statSampler.hpp"
56 #include "runtime/stubRoutines.hpp"
57 #include "runtime/threadCritical.hpp"
58 #include "runtime/timer.hpp"
59 #include "services/attachListener.hpp"
60 #include "services/runtimeService.hpp"
61 #include "thread_linux.inline.hpp"
62 #include "utilities/decoder.hpp"
63 #include "utilities/defaultStream.hpp"
64 #include "utilities/events.hpp"
65 #include "utilities/growableArray.hpp"
66 #include "utilities/vmError.hpp"
67 #ifdef TARGET_ARCH_x86
68 # include "assembler_x86.inline.hpp"
69 # include "nativeInst_x86.hpp"
70 #endif
71 #ifdef TARGET_ARCH_sparc
72 # include "assembler_sparc.inline.hpp"
73 # include "nativeInst_sparc.hpp"
74 #endif
75 #ifdef TARGET_ARCH_zero
76 # include "assembler_zero.inline.hpp"
77 # include "nativeInst_zero.hpp"
78 #endif
79 #ifdef TARGET_ARCH_arm
80 # include "assembler_arm.inline.hpp"
81 # include "nativeInst_arm.hpp"
82 #endif
83 #ifdef TARGET_ARCH_ppc
84 # include "assembler_ppc.inline.hpp"
85 # include "nativeInst_ppc.hpp"
86 #endif
87 #ifdef COMPILER1
88 #include "c1/c1_Runtime1.hpp"
89 #endif
90 #ifdef COMPILER2
91 #include "opto/runtime.hpp"
92 #endif
93
94 // put OS-includes here
95 # include <sys/types.h>
96 # include <sys/mman.h>
97 # include <sys/stat.h>
98 # include <sys/select.h>
99 # include <pthread.h>
100 # include <signal.h>
101 # include <errno.h>
102 # include <dlfcn.h>
103 # include <stdio.h>
104 # include <unistd.h>
105 # include <sys/resource.h>
106 # include <pthread.h>
107 # include <sys/stat.h>
108 # include <sys/time.h>
109 # include <sys/times.h>
110 # include <sys/utsname.h>
111 # include <sys/socket.h>
112 # include <sys/wait.h>
113 # include <pwd.h>
114 # include <poll.h>
115 # include <semaphore.h>
116 # include <fcntl.h>
117 # include <string.h>
118 # include <syscall.h>
119 # include <sys/sysinfo.h>
120 # include <gnu/libc-version.h>
121 # include <sys/ipc.h>
122 # include <sys/shm.h>
123 # include <link.h>
124 # include <stdint.h>
125 # include <inttypes.h>
126 # include <sys/ioctl.h>
127
128 #define MAX_PATH (2 * K)
129
130 // for timer info max values which include all bits
131 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
132 #define SEC_IN_NANOSECS 1000000000LL
133
134 #define LARGEPAGES_BIT (1 << 6)
135 ////////////////////////////////////////////////////////////////////////////////
136 // global variables
137 julong os::Linux::_physical_memory = 0;
138
139 address os::Linux::_initial_thread_stack_bottom = NULL;
140 uintptr_t os::Linux::_initial_thread_stack_size = 0;
141
142 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
143 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
144 Mutex* os::Linux::_createThread_lock = NULL;
145 pthread_t os::Linux::_main_thread;
146 int os::Linux::_page_size = -1;
147 bool os::Linux::_is_floating_stack = false;
148 bool os::Linux::_is_NPTL = false;
149 bool os::Linux::_supports_fast_thread_cpu_time = false;
150 const char * os::Linux::_glibc_version = NULL;
151 const char * os::Linux::_libpthread_version = NULL;
152
153 static jlong initial_time_count=0;
154
155 static int clock_tics_per_sec = 100;
156
157 // For diagnostics to print a message once. see run_periodic_checks
158 static sigset_t check_signal_done;
159 static bool check_signals = true;;
160
161 static pid_t _initial_pid = 0;
162
163 /* Signal number used to suspend/resume a thread */
164
165 /* do not use any signal number less than SIGSEGV, see 4355769 */
166 static int SR_signum = SIGUSR2;
167 sigset_t SR_sigset;
168
169 /* Used to protect dlsym() calls */
170 static pthread_mutex_t dl_mutex;
171
172 #ifdef JAVASE_EMBEDDED
173 class MemNotifyThread: public Thread {
174 friend class VMStructs;
175 public:
176 virtual void run();
177
178 private:
179 static MemNotifyThread* _memnotify_thread;
180 int _fd;
181
182 public:
183
184 // Constructor
185 MemNotifyThread(int fd);
186
187 // Tester
188 bool is_memnotify_thread() const { return true; }
189
190 // Printing
191 char* name() const { return (char*)"Linux MemNotify Thread"; }
192
193 // Returns the single instance of the MemNotifyThread
194 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
195
196 // Create and start the single instance of MemNotifyThread
197 static void start();
198 };
199 #endif // JAVASE_EMBEDDED
200
201 // utility functions
202
203 static int SR_initialize();
204 static int SR_finalize();
205
206 julong os::available_memory() {
207 return Linux::available_memory();
208 }
209
210 julong os::Linux::available_memory() {
211 // values in struct sysinfo are "unsigned long"
212 struct sysinfo si;
213 sysinfo(&si);
214
215 return (julong)si.freeram * si.mem_unit;
216 }
217
218 julong os::physical_memory() {
219 return Linux::physical_memory();
220 }
221
222 julong os::allocatable_physical_memory(julong size) {
223 #ifdef _LP64
224 return size;
225 #else
226 julong result = MIN2(size, (julong)3800*M);
227 if (!is_allocatable(result)) {
228 // See comments under solaris for alignment considerations
229 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
230 result = MIN2(size, reasonable_size);
231 }
232 return result;
233 #endif // _LP64
234 }
235
236 ////////////////////////////////////////////////////////////////////////////////
237 // environment support
238
239 bool os::getenv(const char* name, char* buf, int len) {
240 const char* val = ::getenv(name);
241 if (val != NULL && strlen(val) < (size_t)len) {
242 strcpy(buf, val);
243 return true;
244 }
245 if (len > 0) buf[0] = 0; // return a null string
246 return false;
247 }
248
249
250 // Return true if user is running as root.
251
252 bool os::have_special_privileges() {
253 static bool init = false;
254 static bool privileges = false;
255 if (!init) {
256 privileges = (getuid() != geteuid()) || (getgid() != getegid());
257 init = true;
258 }
259 return privileges;
260 }
261
262
263 #ifndef SYS_gettid
264 // i386: 224, ia64: 1105, amd64: 186, sparc 143
265 #ifdef __ia64__
266 #define SYS_gettid 1105
267 #elif __i386__
268 #define SYS_gettid 224
269 #elif __amd64__
270 #define SYS_gettid 186
271 #elif __sparc__
272 #define SYS_gettid 143
273 #else
274 #error define gettid for the arch
275 #endif
276 #endif
277
278 // Cpu architecture string
279 #if defined(ZERO)
280 static char cpu_arch[] = ZERO_LIBARCH;
281 #elif defined(IA64)
282 static char cpu_arch[] = "ia64";
283 #elif defined(IA32)
284 static char cpu_arch[] = "i386";
285 #elif defined(AMD64)
286 static char cpu_arch[] = "amd64";
287 #elif defined(ARM)
288 static char cpu_arch[] = "arm";
289 #elif defined(PPC)
290 static char cpu_arch[] = "ppc";
291 #elif defined(SPARC)
292 # ifdef _LP64
293 static char cpu_arch[] = "sparcv9";
294 # else
295 static char cpu_arch[] = "sparc";
296 # endif
297 #else
298 #error Add appropriate cpu_arch setting
299 #endif
300
301
302 // pid_t gettid()
303 //
304 // Returns the kernel thread id of the currently running thread. Kernel
305 // thread id is used to access /proc.
306 //
307 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
308 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
309 //
310 pid_t os::Linux::gettid() {
311 int rslt = syscall(SYS_gettid);
312 if (rslt == -1) {
313 // old kernel, no NPTL support
314 return getpid();
315 } else {
316 return (pid_t)rslt;
317 }
318 }
319
320 // Most versions of linux have a bug where the number of processors are
321 // determined by looking at the /proc file system. In a chroot environment,
322 // the system call returns 1. This causes the VM to act as if it is
323 // a single processor and elide locking (see is_MP() call).
324 static bool unsafe_chroot_detected = false;
325 static const char *unstable_chroot_error = "/proc file system not found.\n"
326 "Java may be unstable running multithreaded in a chroot "
327 "environment on Linux when /proc filesystem is not mounted.";
328
329 void os::Linux::initialize_system_info() {
330 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
331 if (processor_count() == 1) {
332 pid_t pid = os::Linux::gettid();
333 char fname[32];
334 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
335 FILE *fp = fopen(fname, "r");
336 if (fp == NULL) {
337 unsafe_chroot_detected = true;
338 } else {
339 fclose(fp);
340 }
341 }
342 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
343 assert(processor_count() > 0, "linux error");
344 }
345
346 void os::init_system_properties_values() {
347 // char arch[12];
348 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
349
350 // The next steps are taken in the product version:
351 //
352 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
353 // This library should be located at:
354 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
355 //
356 // If "/jre/lib/" appears at the right place in the path, then we
357 // assume libjvm[_g].so is installed in a JDK and we use this path.
358 //
359 // Otherwise exit with message: "Could not create the Java virtual machine."
360 //
361 // The following extra steps are taken in the debugging version:
362 //
363 // If "/jre/lib/" does NOT appear at the right place in the path
364 // instead of exit check for $JAVA_HOME environment variable.
365 //
366 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
367 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
368 // it looks like libjvm[_g].so is installed there
369 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
370 //
371 // Otherwise exit.
372 //
373 // Important note: if the location of libjvm.so changes this
374 // code needs to be changed accordingly.
375
376 // The next few definitions allow the code to be verbatim:
377 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
378 #define getenv(n) ::getenv(n)
379
380 /*
381 * See ld(1):
382 * The linker uses the following search paths to locate required
383 * shared libraries:
384 * 1: ...
385 * ...
386 * 7: The default directories, normally /lib and /usr/lib.
387 */
388 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
389 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
390 #else
391 #define DEFAULT_LIBPATH "/lib:/usr/lib"
392 #endif
393
394 #define EXTENSIONS_DIR "/lib/ext"
395 #define ENDORSED_DIR "/lib/endorsed"
396 #define REG_DIR "/usr/java/packages"
397
398 {
399 /* sysclasspath, java_home, dll_dir */
400 {
401 char *home_path;
402 char *dll_path;
403 char *pslash;
404 char buf[MAXPATHLEN];
405 os::jvm_path(buf, sizeof(buf));
406
407 // Found the full path to libjvm.so.
408 // Now cut the path to <java_home>/jre if we can.
409 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
410 pslash = strrchr(buf, '/');
411 if (pslash != NULL)
412 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
413 dll_path = malloc(strlen(buf) + 1);
414 if (dll_path == NULL)
415 return;
416 strcpy(dll_path, buf);
417 Arguments::set_dll_dir(dll_path);
418
419 if (pslash != NULL) {
420 pslash = strrchr(buf, '/');
421 if (pslash != NULL) {
422 *pslash = '\0'; /* get rid of /<arch> */
423 pslash = strrchr(buf, '/');
424 if (pslash != NULL)
425 *pslash = '\0'; /* get rid of /lib */
426 }
427 }
428
429 home_path = malloc(strlen(buf) + 1);
430 if (home_path == NULL)
431 return;
432 strcpy(home_path, buf);
433 Arguments::set_java_home(home_path);
434
435 if (!set_boot_path('/', ':'))
436 return;
437 }
438
439 /*
440 * Where to look for native libraries
441 *
442 * Note: Due to a legacy implementation, most of the library path
443 * is set in the launcher. This was to accomodate linking restrictions
444 * on legacy Linux implementations (which are no longer supported).
445 * Eventually, all the library path setting will be done here.
446 *
447 * However, to prevent the proliferation of improperly built native
448 * libraries, the new path component /usr/java/packages is added here.
449 * Eventually, all the library path setting will be done here.
450 */
451 {
452 char *ld_library_path;
453
454 /*
455 * Construct the invariant part of ld_library_path. Note that the
456 * space for the colon and the trailing null are provided by the
457 * nulls included by the sizeof operator (so actually we allocate
458 * a byte more than necessary).
459 */
460 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
461 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
462 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
463
464 /*
465 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
466 * should always exist (until the legacy problem cited above is
467 * addressed).
468 */
469 char *v = getenv("LD_LIBRARY_PATH");
470 if (v != NULL) {
471 char *t = ld_library_path;
472 /* That's +1 for the colon and +1 for the trailing '\0' */
473 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
474 sprintf(ld_library_path, "%s:%s", v, t);
475 }
476 Arguments::set_library_path(ld_library_path);
477 }
478
479 /*
480 * Extensions directories.
481 *
482 * Note that the space for the colon and the trailing null are provided
483 * by the nulls included by the sizeof operator (so actually one byte more
484 * than necessary is allocated).
485 */
486 {
487 char *buf = malloc(strlen(Arguments::get_java_home()) +
488 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
489 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
490 Arguments::get_java_home());
491 Arguments::set_ext_dirs(buf);
492 }
493
494 /* Endorsed standards default directory. */
495 {
496 char * buf;
497 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
498 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
499 Arguments::set_endorsed_dirs(buf);
500 }
501 }
502
503 #undef malloc
504 #undef getenv
505 #undef EXTENSIONS_DIR
506 #undef ENDORSED_DIR
507
508 // Done
509 return;
510 }
511
512 ////////////////////////////////////////////////////////////////////////////////
513 // breakpoint support
514
515 void os::breakpoint() {
516 BREAKPOINT;
517 }
518
519 extern "C" void breakpoint() {
520 // use debugger to set breakpoint here
521 }
522
523 ////////////////////////////////////////////////////////////////////////////////
524 // signal support
525
526 debug_only(static bool signal_sets_initialized = false);
527 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
528
529 bool os::Linux::is_sig_ignored(int sig) {
530 struct sigaction oact;
531 sigaction(sig, (struct sigaction*)NULL, &oact);
532 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
533 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
534 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
535 return true;
536 else
537 return false;
538 }
539
540 void os::Linux::signal_sets_init() {
541 // Should also have an assertion stating we are still single-threaded.
542 assert(!signal_sets_initialized, "Already initialized");
543 // Fill in signals that are necessarily unblocked for all threads in
544 // the VM. Currently, we unblock the following signals:
545 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
546 // by -Xrs (=ReduceSignalUsage));
547 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
548 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
549 // the dispositions or masks wrt these signals.
550 // Programs embedding the VM that want to use the above signals for their
551 // own purposes must, at this time, use the "-Xrs" option to prevent
552 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
553 // (See bug 4345157, and other related bugs).
554 // In reality, though, unblocking these signals is really a nop, since
555 // these signals are not blocked by default.
556 sigemptyset(&unblocked_sigs);
557 sigemptyset(&allowdebug_blocked_sigs);
558 sigaddset(&unblocked_sigs, SIGILL);
559 sigaddset(&unblocked_sigs, SIGSEGV);
560 sigaddset(&unblocked_sigs, SIGBUS);
561 sigaddset(&unblocked_sigs, SIGFPE);
562 sigaddset(&unblocked_sigs, SR_signum);
563
564 if (!ReduceSignalUsage) {
565 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
566 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
567 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
568 }
569 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
570 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
571 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
572 }
573 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
574 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
575 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
576 }
577 }
578 // Fill in signals that are blocked by all but the VM thread.
579 sigemptyset(&vm_sigs);
580 if (!ReduceSignalUsage)
581 sigaddset(&vm_sigs, BREAK_SIGNAL);
582 debug_only(signal_sets_initialized = true);
583
584 }
585
586 // These are signals that are unblocked while a thread is running Java.
587 // (For some reason, they get blocked by default.)
588 sigset_t* os::Linux::unblocked_signals() {
589 assert(signal_sets_initialized, "Not initialized");
590 return &unblocked_sigs;
591 }
592
593 // These are the signals that are blocked while a (non-VM) thread is
594 // running Java. Only the VM thread handles these signals.
595 sigset_t* os::Linux::vm_signals() {
596 assert(signal_sets_initialized, "Not initialized");
597 return &vm_sigs;
598 }
599
600 // These are signals that are blocked during cond_wait to allow debugger in
601 sigset_t* os::Linux::allowdebug_blocked_signals() {
602 assert(signal_sets_initialized, "Not initialized");
603 return &allowdebug_blocked_sigs;
604 }
605
606 void os::Linux::hotspot_sigmask(Thread* thread) {
607
608 //Save caller's signal mask before setting VM signal mask
609 sigset_t caller_sigmask;
610 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
611
612 OSThread* osthread = thread->osthread();
613 osthread->set_caller_sigmask(caller_sigmask);
614
615 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
616
617 if (!ReduceSignalUsage) {
618 if (thread->is_VM_thread()) {
619 // Only the VM thread handles BREAK_SIGNAL ...
620 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
621 } else {
622 // ... all other threads block BREAK_SIGNAL
623 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
624 }
625 }
626 }
627
628 //////////////////////////////////////////////////////////////////////////////
629 // detecting pthread library
630
631 void os::Linux::libpthread_init() {
632 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
633 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
634 // generic name for earlier versions.
635 // Define macros here so we can build HotSpot on old systems.
636 # ifndef _CS_GNU_LIBC_VERSION
637 # define _CS_GNU_LIBC_VERSION 2
638 # endif
639 # ifndef _CS_GNU_LIBPTHREAD_VERSION
640 # define _CS_GNU_LIBPTHREAD_VERSION 3
641 # endif
642
643 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
644 if (n > 0) {
645 char *str = (char *)malloc(n);
646 confstr(_CS_GNU_LIBC_VERSION, str, n);
647 os::Linux::set_glibc_version(str);
648 } else {
649 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
650 static char _gnu_libc_version[32];
651 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
652 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
653 os::Linux::set_glibc_version(_gnu_libc_version);
654 }
655
656 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
657 if (n > 0) {
658 char *str = (char *)malloc(n);
659 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
660 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
661 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
662 // is the case. LinuxThreads has a hard limit on max number of threads.
663 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
664 // On the other hand, NPTL does not have such a limit, sysconf()
665 // will return -1 and errno is not changed. Check if it is really NPTL.
666 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
667 strstr(str, "NPTL") &&
668 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
669 free(str);
670 os::Linux::set_libpthread_version("linuxthreads");
671 } else {
672 os::Linux::set_libpthread_version(str);
673 }
674 } else {
675 // glibc before 2.3.2 only has LinuxThreads.
676 os::Linux::set_libpthread_version("linuxthreads");
677 }
678
679 if (strstr(libpthread_version(), "NPTL")) {
680 os::Linux::set_is_NPTL();
681 } else {
682 os::Linux::set_is_LinuxThreads();
683 }
684
685 // LinuxThreads have two flavors: floating-stack mode, which allows variable
686 // stack size; and fixed-stack mode. NPTL is always floating-stack.
687 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
688 os::Linux::set_is_floating_stack();
689 }
690 }
691
692 /////////////////////////////////////////////////////////////////////////////
693 // thread stack
694
695 // Force Linux kernel to expand current thread stack. If "bottom" is close
696 // to the stack guard, caller should block all signals.
697 //
698 // MAP_GROWSDOWN:
699 // A special mmap() flag that is used to implement thread stacks. It tells
700 // kernel that the memory region should extend downwards when needed. This
701 // allows early versions of LinuxThreads to only mmap the first few pages
702 // when creating a new thread. Linux kernel will automatically expand thread
703 // stack as needed (on page faults).
704 //
705 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
706 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
707 // region, it's hard to tell if the fault is due to a legitimate stack
708 // access or because of reading/writing non-exist memory (e.g. buffer
709 // overrun). As a rule, if the fault happens below current stack pointer,
710 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
711 // application (see Linux kernel fault.c).
712 //
713 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
714 // stack overflow detection.
715 //
716 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
717 // not use this flag. However, the stack of initial thread is not created
718 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
719 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
720 // and then attach the thread to JVM.
721 //
722 // To get around the problem and allow stack banging on Linux, we need to
723 // manually expand thread stack after receiving the SIGSEGV.
724 //
725 // There are two ways to expand thread stack to address "bottom", we used
726 // both of them in JVM before 1.5:
727 // 1. adjust stack pointer first so that it is below "bottom", and then
728 // touch "bottom"
729 // 2. mmap() the page in question
730 //
731 // Now alternate signal stack is gone, it's harder to use 2. For instance,
732 // if current sp is already near the lower end of page 101, and we need to
733 // call mmap() to map page 100, it is possible that part of the mmap() frame
734 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
735 // That will destroy the mmap() frame and cause VM to crash.
736 //
737 // The following code works by adjusting sp first, then accessing the "bottom"
738 // page to force a page fault. Linux kernel will then automatically expand the
739 // stack mapping.
740 //
741 // _expand_stack_to() assumes its frame size is less than page size, which
742 // should always be true if the function is not inlined.
743
744 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
745 #define NOINLINE
746 #else
747 #define NOINLINE __attribute__ ((noinline))
748 #endif
749
750 static void _expand_stack_to(address bottom) NOINLINE;
751
752 static void _expand_stack_to(address bottom) {
753 address sp;
754 size_t size;
755 volatile char *p;
756
757 // Adjust bottom to point to the largest address within the same page, it
758 // gives us a one-page buffer if alloca() allocates slightly more memory.
759 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
760 bottom += os::Linux::page_size() - 1;
761
762 // sp might be slightly above current stack pointer; if that's the case, we
763 // will alloca() a little more space than necessary, which is OK. Don't use
764 // os::current_stack_pointer(), as its result can be slightly below current
765 // stack pointer, causing us to not alloca enough to reach "bottom".
766 sp = (address)&sp;
767
768 if (sp > bottom) {
769 size = sp - bottom;
770 p = (volatile char *)alloca(size);
771 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
772 p[0] = '\0';
773 }
774 }
775
776 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
777 assert(t!=NULL, "just checking");
778 assert(t->osthread()->expanding_stack(), "expand should be set");
779 assert(t->stack_base() != NULL, "stack_base was not initialized");
780
781 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
782 sigset_t mask_all, old_sigset;
783 sigfillset(&mask_all);
784 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
785 _expand_stack_to(addr);
786 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
787 return true;
788 }
789 return false;
790 }
791
792 //////////////////////////////////////////////////////////////////////////////
793 // create new thread
794
795 static address highest_vm_reserved_address();
796
797 // check if it's safe to start a new thread
798 static bool _thread_safety_check(Thread* thread) {
799 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
800 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
801 // Heap is mmap'ed at lower end of memory space. Thread stacks are
802 // allocated (MAP_FIXED) from high address space. Every thread stack
803 // occupies a fixed size slot (usually 2Mbytes, but user can change
804 // it to other values if they rebuild LinuxThreads).
805 //
806 // Problem with MAP_FIXED is that mmap() can still succeed even part of
807 // the memory region has already been mmap'ed. That means if we have too
808 // many threads and/or very large heap, eventually thread stack will
809 // collide with heap.
810 //
811 // Here we try to prevent heap/stack collision by comparing current
812 // stack bottom with the highest address that has been mmap'ed by JVM
813 // plus a safety margin for memory maps created by native code.
814 //
815 // This feature can be disabled by setting ThreadSafetyMargin to 0
816 //
817 if (ThreadSafetyMargin > 0) {
818 address stack_bottom = os::current_stack_base() - os::current_stack_size();
819
820 // not safe if our stack extends below the safety margin
821 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
822 } else {
823 return true;
824 }
825 } else {
826 // Floating stack LinuxThreads or NPTL:
827 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
828 // there's not enough space left, pthread_create() will fail. If we come
829 // here, that means enough space has been reserved for stack.
830 return true;
831 }
832 }
833
834 // Thread start routine for all newly created threads
835 static void *java_start(Thread *thread) {
836 // Try to randomize the cache line index of hot stack frames.
837 // This helps when threads of the same stack traces evict each other's
838 // cache lines. The threads can be either from the same JVM instance, or
839 // from different JVM instances. The benefit is especially true for
840 // processors with hyperthreading technology.
841 static int counter = 0;
842 int pid = os::current_process_id();
843 alloca(((pid ^ counter++) & 7) * 128);
844
845 ThreadLocalStorage::set_thread(thread);
846
847 OSThread* osthread = thread->osthread();
848 Monitor* sync = osthread->startThread_lock();
849
850 // non floating stack LinuxThreads needs extra check, see above
851 if (!_thread_safety_check(thread)) {
852 // notify parent thread
853 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
854 osthread->set_state(ZOMBIE);
855 sync->notify_all();
856 return NULL;
857 }
858
859 // thread_id is kernel thread id (similar to Solaris LWP id)
860 osthread->set_thread_id(os::Linux::gettid());
861
862 if (UseNUMA) {
863 int lgrp_id = os::numa_get_group_id();
864 if (lgrp_id != -1) {
865 thread->set_lgrp_id(lgrp_id);
866 }
867 }
868 // initialize signal mask for this thread
869 os::Linux::hotspot_sigmask(thread);
870
871 // initialize floating point control register
872 os::Linux::init_thread_fpu_state();
873
874 // handshaking with parent thread
875 {
876 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
877
878 // notify parent thread
879 osthread->set_state(INITIALIZED);
880 sync->notify_all();
881
882 // wait until os::start_thread()
883 while (osthread->get_state() == INITIALIZED) {
884 sync->wait(Mutex::_no_safepoint_check_flag);
885 }
886 }
887
888 // call one more level start routine
889 thread->run();
890
891 return 0;
892 }
893
894 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
895 assert(thread->osthread() == NULL, "caller responsible");
896
897 // Allocate the OSThread object
898 OSThread* osthread = new OSThread(NULL, NULL);
899 if (osthread == NULL) {
900 return false;
901 }
902
903 // set the correct thread state
904 osthread->set_thread_type(thr_type);
905
906 // Initial state is ALLOCATED but not INITIALIZED
907 osthread->set_state(ALLOCATED);
908
909 thread->set_osthread(osthread);
910
911 // init thread attributes
912 pthread_attr_t attr;
913 pthread_attr_init(&attr);
914 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
915
916 // stack size
917 if (os::Linux::supports_variable_stack_size()) {
918 // calculate stack size if it's not specified by caller
919 if (stack_size == 0) {
920 stack_size = os::Linux::default_stack_size(thr_type);
921
922 switch (thr_type) {
923 case os::java_thread:
924 // Java threads use ThreadStackSize which default value can be
925 // changed with the flag -Xss
926 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
927 stack_size = JavaThread::stack_size_at_create();
928 break;
929 case os::compiler_thread:
930 if (CompilerThreadStackSize > 0) {
931 stack_size = (size_t)(CompilerThreadStackSize * K);
932 break;
933 } // else fall through:
934 // use VMThreadStackSize if CompilerThreadStackSize is not defined
935 case os::vm_thread:
936 case os::pgc_thread:
937 case os::cgc_thread:
938 case os::watcher_thread:
939 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
940 break;
941 }
942 }
943
944 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
945 pthread_attr_setstacksize(&attr, stack_size);
946 } else {
947 // let pthread_create() pick the default value.
948 }
949
950 // glibc guard page
951 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
952
953 ThreadState state;
954
955 {
956 // Serialize thread creation if we are running with fixed stack LinuxThreads
957 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
958 if (lock) {
959 os::Linux::createThread_lock()->lock_without_safepoint_check();
960 }
961
962 pthread_t tid;
963 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
964
965 pthread_attr_destroy(&attr);
966
967 if (ret != 0) {
968 if (PrintMiscellaneous && (Verbose || WizardMode)) {
969 perror("pthread_create()");
970 }
971 // Need to clean up stuff we've allocated so far
972 thread->set_osthread(NULL);
973 delete osthread;
974 if (lock) os::Linux::createThread_lock()->unlock();
975 return false;
976 }
977
978 // Store pthread info into the OSThread
979 osthread->set_pthread_id(tid);
980
981 // Wait until child thread is either initialized or aborted
982 {
983 Monitor* sync_with_child = osthread->startThread_lock();
984 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
985 while ((state = osthread->get_state()) == ALLOCATED) {
986 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
987 }
988 }
989
990 if (lock) {
991 os::Linux::createThread_lock()->unlock();
992 }
993 }
994
995 // Aborted due to thread limit being reached
996 if (state == ZOMBIE) {
997 thread->set_osthread(NULL);
998 delete osthread;
999 return false;
1000 }
1001
1002 // The thread is returned suspended (in state INITIALIZED),
1003 // and is started higher up in the call chain
1004 assert(state == INITIALIZED, "race condition");
1005 return true;
1006 }
1007
1008 /////////////////////////////////////////////////////////////////////////////
1009 // attach existing thread
1010
1011 // bootstrap the main thread
1012 bool os::create_main_thread(JavaThread* thread) {
1013 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1014 return create_attached_thread(thread);
1015 }
1016
1017 bool os::create_attached_thread(JavaThread* thread) {
1018 #ifdef ASSERT
1019 thread->verify_not_published();
1020 #endif
1021
1022 // Allocate the OSThread object
1023 OSThread* osthread = new OSThread(NULL, NULL);
1024
1025 if (osthread == NULL) {
1026 return false;
1027 }
1028
1029 // Store pthread info into the OSThread
1030 osthread->set_thread_id(os::Linux::gettid());
1031 osthread->set_pthread_id(::pthread_self());
1032
1033 // initialize floating point control register
1034 os::Linux::init_thread_fpu_state();
1035
1036 // Initial thread state is RUNNABLE
1037 osthread->set_state(RUNNABLE);
1038
1039 thread->set_osthread(osthread);
1040
1041 if (UseNUMA) {
1042 int lgrp_id = os::numa_get_group_id();
1043 if (lgrp_id != -1) {
1044 thread->set_lgrp_id(lgrp_id);
1045 }
1046 }
1047
1048 if (os::Linux::is_initial_thread()) {
1049 // If current thread is initial thread, its stack is mapped on demand,
1050 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1051 // the entire stack region to avoid SEGV in stack banging.
1052 // It is also useful to get around the heap-stack-gap problem on SuSE
1053 // kernel (see 4821821 for details). We first expand stack to the top
1054 // of yellow zone, then enable stack yellow zone (order is significant,
1055 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1056 // is no gap between the last two virtual memory regions.
1057
1058 JavaThread *jt = (JavaThread *)thread;
1059 address addr = jt->stack_yellow_zone_base();
1060 assert(addr != NULL, "initialization problem?");
1061 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1062
1063 osthread->set_expanding_stack();
1064 os::Linux::manually_expand_stack(jt, addr);
1065 osthread->clear_expanding_stack();
1066 }
1067
1068 // initialize signal mask for this thread
1069 // and save the caller's signal mask
1070 os::Linux::hotspot_sigmask(thread);
1071
1072 return true;
1073 }
1074
1075 void os::pd_start_thread(Thread* thread) {
1076 OSThread * osthread = thread->osthread();
1077 assert(osthread->get_state() != INITIALIZED, "just checking");
1078 Monitor* sync_with_child = osthread->startThread_lock();
1079 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1080 sync_with_child->notify();
1081 }
1082
1083 // Free Linux resources related to the OSThread
1084 void os::free_thread(OSThread* osthread) {
1085 assert(osthread != NULL, "osthread not set");
1086
1087 if (Thread::current()->osthread() == osthread) {
1088 // Restore caller's signal mask
1089 sigset_t sigmask = osthread->caller_sigmask();
1090 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1091 }
1092
1093 delete osthread;
1094 }
1095
1096 //////////////////////////////////////////////////////////////////////////////
1097 // thread local storage
1098
1099 int os::allocate_thread_local_storage() {
1100 pthread_key_t key;
1101 int rslt = pthread_key_create(&key, NULL);
1102 assert(rslt == 0, "cannot allocate thread local storage");
1103 return (int)key;
1104 }
1105
1106 // Note: This is currently not used by VM, as we don't destroy TLS key
1107 // on VM exit.
1108 void os::free_thread_local_storage(int index) {
1109 int rslt = pthread_key_delete((pthread_key_t)index);
1110 assert(rslt == 0, "invalid index");
1111 }
1112
1113 void os::thread_local_storage_at_put(int index, void* value) {
1114 int rslt = pthread_setspecific((pthread_key_t)index, value);
1115 assert(rslt == 0, "pthread_setspecific failed");
1116 }
1117
1118 extern "C" Thread* get_thread() {
1119 return ThreadLocalStorage::thread();
1120 }
1121
1122 //////////////////////////////////////////////////////////////////////////////
1123 // initial thread
1124
1125 // Check if current thread is the initial thread, similar to Solaris thr_main.
1126 bool os::Linux::is_initial_thread(void) {
1127 char dummy;
1128 // If called before init complete, thread stack bottom will be null.
1129 // Can be called if fatal error occurs before initialization.
1130 if (initial_thread_stack_bottom() == NULL) return false;
1131 assert(initial_thread_stack_bottom() != NULL &&
1132 initial_thread_stack_size() != 0,
1133 "os::init did not locate initial thread's stack region");
1134 if ((address)&dummy >= initial_thread_stack_bottom() &&
1135 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1136 return true;
1137 else return false;
1138 }
1139
1140 // Find the virtual memory area that contains addr
1141 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1142 FILE *fp = fopen("/proc/self/maps", "r");
1143 if (fp) {
1144 address low, high;
1145 while (!feof(fp)) {
1146 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1147 if (low <= addr && addr < high) {
1148 if (vma_low) *vma_low = low;
1149 if (vma_high) *vma_high = high;
1150 fclose (fp);
1151 return true;
1152 }
1153 }
1154 for (;;) {
1155 int ch = fgetc(fp);
1156 if (ch == EOF || ch == (int)'\n') break;
1157 }
1158 }
1159 fclose(fp);
1160 }
1161 return false;
1162 }
1163
1164 // Locate initial thread stack. This special handling of initial thread stack
1165 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1166 // bogus value for initial thread.
1167 void os::Linux::capture_initial_stack(size_t max_size) {
1168 // stack size is the easy part, get it from RLIMIT_STACK
1169 size_t stack_size;
1170 struct rlimit rlim;
1171 getrlimit(RLIMIT_STACK, &rlim);
1172 stack_size = rlim.rlim_cur;
1173
1174 // 6308388: a bug in ld.so will relocate its own .data section to the
1175 // lower end of primordial stack; reduce ulimit -s value a little bit
1176 // so we won't install guard page on ld.so's data section.
1177 stack_size -= 2 * page_size();
1178
1179 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1180 // 7.1, in both cases we will get 2G in return value.
1181 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1182 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1183 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1184 // in case other parts in glibc still assumes 2M max stack size.
1185 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1186 #ifndef IA64
1187 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1188 #else
1189 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1190 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1191 #endif
1192
1193 // Try to figure out where the stack base (top) is. This is harder.
1194 //
1195 // When an application is started, glibc saves the initial stack pointer in
1196 // a global variable "__libc_stack_end", which is then used by system
1197 // libraries. __libc_stack_end should be pretty close to stack top. The
1198 // variable is available since the very early days. However, because it is
1199 // a private interface, it could disappear in the future.
1200 //
1201 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1202 // to __libc_stack_end, it is very close to stack top, but isn't the real
1203 // stack top. Note that /proc may not exist if VM is running as a chroot
1204 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1205 // /proc/<pid>/stat could change in the future (though unlikely).
1206 //
1207 // We try __libc_stack_end first. If that doesn't work, look for
1208 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1209 // as a hint, which should work well in most cases.
1210
1211 uintptr_t stack_start;
1212
1213 // try __libc_stack_end first
1214 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1215 if (p && *p) {
1216 stack_start = *p;
1217 } else {
1218 // see if we can get the start_stack field from /proc/self/stat
1219 FILE *fp;
1220 int pid;
1221 char state;
1222 int ppid;
1223 int pgrp;
1224 int session;
1225 int nr;
1226 int tpgrp;
1227 unsigned long flags;
1228 unsigned long minflt;
1229 unsigned long cminflt;
1230 unsigned long majflt;
1231 unsigned long cmajflt;
1232 unsigned long utime;
1233 unsigned long stime;
1234 long cutime;
1235 long cstime;
1236 long prio;
1237 long nice;
1238 long junk;
1239 long it_real;
1240 uintptr_t start;
1241 uintptr_t vsize;
1242 intptr_t rss;
1243 uintptr_t rsslim;
1244 uintptr_t scodes;
1245 uintptr_t ecode;
1246 int i;
1247
1248 // Figure what the primordial thread stack base is. Code is inspired
1249 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1250 // followed by command name surrounded by parentheses, state, etc.
1251 char stat[2048];
1252 int statlen;
1253
1254 fp = fopen("/proc/self/stat", "r");
1255 if (fp) {
1256 statlen = fread(stat, 1, 2047, fp);
1257 stat[statlen] = '\0';
1258 fclose(fp);
1259
1260 // Skip pid and the command string. Note that we could be dealing with
1261 // weird command names, e.g. user could decide to rename java launcher
1262 // to "java 1.4.2 :)", then the stat file would look like
1263 // 1234 (java 1.4.2 :)) R ... ...
1264 // We don't really need to know the command string, just find the last
1265 // occurrence of ")" and then start parsing from there. See bug 4726580.
1266 char * s = strrchr(stat, ')');
1267
1268 i = 0;
1269 if (s) {
1270 // Skip blank chars
1271 do s++; while (isspace(*s));
1272
1273 #define _UFM UINTX_FORMAT
1274 #define _DFM INTX_FORMAT
1275
1276 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1277 /* 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 */
1278 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,
1279 &state, /* 3 %c */
1280 &ppid, /* 4 %d */
1281 &pgrp, /* 5 %d */
1282 &session, /* 6 %d */
1283 &nr, /* 7 %d */
1284 &tpgrp, /* 8 %d */
1285 &flags, /* 9 %lu */
1286 &minflt, /* 10 %lu */
1287 &cminflt, /* 11 %lu */
1288 &majflt, /* 12 %lu */
1289 &cmajflt, /* 13 %lu */
1290 &utime, /* 14 %lu */
1291 &stime, /* 15 %lu */
1292 &cutime, /* 16 %ld */
1293 &cstime, /* 17 %ld */
1294 &prio, /* 18 %ld */
1295 &nice, /* 19 %ld */
1296 &junk, /* 20 %ld */
1297 &it_real, /* 21 %ld */
1298 &start, /* 22 UINTX_FORMAT */
1299 &vsize, /* 23 UINTX_FORMAT */
1300 &rss, /* 24 INTX_FORMAT */
1301 &rsslim, /* 25 UINTX_FORMAT */
1302 &scodes, /* 26 UINTX_FORMAT */
1303 &ecode, /* 27 UINTX_FORMAT */
1304 &stack_start); /* 28 UINTX_FORMAT */
1305 }
1306
1307 #undef _UFM
1308 #undef _DFM
1309
1310 if (i != 28 - 2) {
1311 assert(false, "Bad conversion from /proc/self/stat");
1312 // product mode - assume we are the initial thread, good luck in the
1313 // embedded case.
1314 warning("Can't detect initial thread stack location - bad conversion");
1315 stack_start = (uintptr_t) &rlim;
1316 }
1317 } else {
1318 // For some reason we can't open /proc/self/stat (for example, running on
1319 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1320 // most cases, so don't abort:
1321 warning("Can't detect initial thread stack location - no /proc/self/stat");
1322 stack_start = (uintptr_t) &rlim;
1323 }
1324 }
1325
1326 // Now we have a pointer (stack_start) very close to the stack top, the
1327 // next thing to do is to figure out the exact location of stack top. We
1328 // can find out the virtual memory area that contains stack_start by
1329 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1330 // and its upper limit is the real stack top. (again, this would fail if
1331 // running inside chroot, because /proc may not exist.)
1332
1333 uintptr_t stack_top;
1334 address low, high;
1335 if (find_vma((address)stack_start, &low, &high)) {
1336 // success, "high" is the true stack top. (ignore "low", because initial
1337 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1338 stack_top = (uintptr_t)high;
1339 } else {
1340 // failed, likely because /proc/self/maps does not exist
1341 warning("Can't detect initial thread stack location - find_vma failed");
1342 // best effort: stack_start is normally within a few pages below the real
1343 // stack top, use it as stack top, and reduce stack size so we won't put
1344 // guard page outside stack.
1345 stack_top = stack_start;
1346 stack_size -= 16 * page_size();
1347 }
1348
1349 // stack_top could be partially down the page so align it
1350 stack_top = align_size_up(stack_top, page_size());
1351
1352 if (max_size && stack_size > max_size) {
1353 _initial_thread_stack_size = max_size;
1354 } else {
1355 _initial_thread_stack_size = stack_size;
1356 }
1357
1358 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1359 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1360 }
1361
1362 ////////////////////////////////////////////////////////////////////////////////
1363 // time support
1364
1365 // Time since start-up in seconds to a fine granularity.
1366 // Used by VMSelfDestructTimer and the MemProfiler.
1367 double os::elapsedTime() {
1368
1369 return (double)(os::elapsed_counter()) * 0.000001;
1370 }
1371
1372 jlong os::elapsed_counter() {
1373 timeval time;
1374 int status = gettimeofday(&time, NULL);
1375 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1376 }
1377
1378 jlong os::elapsed_frequency() {
1379 return (1000 * 1000);
1380 }
1381
1382 // For now, we say that linux does not support vtime. I have no idea
1383 // whether it can actually be made to (DLD, 9/13/05).
1384
1385 bool os::supports_vtime() { return false; }
1386 bool os::enable_vtime() { return false; }
1387 bool os::vtime_enabled() { return false; }
1388 double os::elapsedVTime() {
1389 // better than nothing, but not much
1390 return elapsedTime();
1391 }
1392
1393 jlong os::javaTimeMillis() {
1394 timeval time;
1395 int status = gettimeofday(&time, NULL);
1396 assert(status != -1, "linux error");
1397 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1398 }
1399
1400 #ifndef CLOCK_MONOTONIC
1401 #define CLOCK_MONOTONIC (1)
1402 #endif
1403
1404 void os::Linux::clock_init() {
1405 // we do dlopen's in this particular order due to bug in linux
1406 // dynamical loader (see 6348968) leading to crash on exit
1407 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1408 if (handle == NULL) {
1409 handle = dlopen("librt.so", RTLD_LAZY);
1410 }
1411
1412 if (handle) {
1413 int (*clock_getres_func)(clockid_t, struct timespec*) =
1414 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1415 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1416 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1417 if (clock_getres_func && clock_gettime_func) {
1418 // See if monotonic clock is supported by the kernel. Note that some
1419 // early implementations simply return kernel jiffies (updated every
1420 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1421 // for nano time (though the monotonic property is still nice to have).
1422 // It's fixed in newer kernels, however clock_getres() still returns
1423 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1424 // resolution for now. Hopefully as people move to new kernels, this
1425 // won't be a problem.
1426 struct timespec res;
1427 struct timespec tp;
1428 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1429 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1430 // yes, monotonic clock is supported
1431 _clock_gettime = clock_gettime_func;
1432 } else {
1433 // close librt if there is no monotonic clock
1434 dlclose(handle);
1435 }
1436 }
1437 }
1438 }
1439
1440 #ifndef SYS_clock_getres
1441
1442 #if defined(IA32) || defined(AMD64)
1443 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1444 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1445 #else
1446 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1447 #define sys_clock_getres(x,y) -1
1448 #endif
1449
1450 #else
1451 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1452 #endif
1453
1454 void os::Linux::fast_thread_clock_init() {
1455 if (!UseLinuxPosixThreadCPUClocks) {
1456 return;
1457 }
1458 clockid_t clockid;
1459 struct timespec tp;
1460 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1461 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1462
1463 // Switch to using fast clocks for thread cpu time if
1464 // the sys_clock_getres() returns 0 error code.
1465 // Note, that some kernels may support the current thread
1466 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1467 // returned by the pthread_getcpuclockid().
1468 // If the fast Posix clocks are supported then the sys_clock_getres()
1469 // must return at least tp.tv_sec == 0 which means a resolution
1470 // better than 1 sec. This is extra check for reliability.
1471
1472 if(pthread_getcpuclockid_func &&
1473 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1474 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1475
1476 _supports_fast_thread_cpu_time = true;
1477 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1478 }
1479 }
1480
1481 jlong os::javaTimeNanos() {
1482 if (Linux::supports_monotonic_clock()) {
1483 struct timespec tp;
1484 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1485 assert(status == 0, "gettime error");
1486 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1487 return result;
1488 } else {
1489 timeval time;
1490 int status = gettimeofday(&time, NULL);
1491 assert(status != -1, "linux error");
1492 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1493 return 1000 * usecs;
1494 }
1495 }
1496
1497 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1498 if (Linux::supports_monotonic_clock()) {
1499 info_ptr->max_value = ALL_64_BITS;
1500
1501 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1502 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1503 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1504 } else {
1505 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1506 info_ptr->max_value = ALL_64_BITS;
1507
1508 // gettimeofday is a real time clock so it skips
1509 info_ptr->may_skip_backward = true;
1510 info_ptr->may_skip_forward = true;
1511 }
1512
1513 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1514 }
1515
1516 // Return the real, user, and system times in seconds from an
1517 // arbitrary fixed point in the past.
1518 bool os::getTimesSecs(double* process_real_time,
1519 double* process_user_time,
1520 double* process_system_time) {
1521 struct tms ticks;
1522 clock_t real_ticks = times(&ticks);
1523
1524 if (real_ticks == (clock_t) (-1)) {
1525 return false;
1526 } else {
1527 double ticks_per_second = (double) clock_tics_per_sec;
1528 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1529 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1530 *process_real_time = ((double) real_ticks) / ticks_per_second;
1531
1532 return true;
1533 }
1534 }
1535
1536
1537 char * os::local_time_string(char *buf, size_t buflen) {
1538 struct tm t;
1539 time_t long_time;
1540 time(&long_time);
1541 localtime_r(&long_time, &t);
1542 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1543 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1544 t.tm_hour, t.tm_min, t.tm_sec);
1545 return buf;
1546 }
1547
1548 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1549 return localtime_r(clock, res);
1550 }
1551
1552 ////////////////////////////////////////////////////////////////////////////////
1553 // runtime exit support
1554
1555 // Note: os::shutdown() might be called very early during initialization, or
1556 // called from signal handler. Before adding something to os::shutdown(), make
1557 // sure it is async-safe and can handle partially initialized VM.
1558 void os::shutdown() {
1559
1560 // allow PerfMemory to attempt cleanup of any persistent resources
1561 perfMemory_exit();
1562
1563 // needs to remove object in file system
1564 AttachListener::abort();
1565
1566 // flush buffered output, finish log files
1567 ostream_abort();
1568
1569 // Check for abort hook
1570 abort_hook_t abort_hook = Arguments::abort_hook();
1571 if (abort_hook != NULL) {
1572 abort_hook();
1573 }
1574
1575 }
1576
1577 // Note: os::abort() might be called very early during initialization, or
1578 // called from signal handler. Before adding something to os::abort(), make
1579 // sure it is async-safe and can handle partially initialized VM.
1580 void os::abort(bool dump_core) {
1581 os::shutdown();
1582 if (dump_core) {
1583 #ifndef PRODUCT
1584 fdStream out(defaultStream::output_fd());
1585 out.print_raw("Current thread is ");
1586 char buf[16];
1587 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1588 out.print_raw_cr(buf);
1589 out.print_raw_cr("Dumping core ...");
1590 #endif
1591 ::abort(); // dump core
1592 }
1593
1594 ::exit(1);
1595 }
1596
1597 // Die immediately, no exit hook, no abort hook, no cleanup.
1598 void os::die() {
1599 // _exit() on LinuxThreads only kills current thread
1600 ::abort();
1601 }
1602
1603 // unused on linux for now.
1604 void os::set_error_file(const char *logfile) {}
1605
1606
1607 // This method is a copy of JDK's sysGetLastErrorString
1608 // from src/solaris/hpi/src/system_md.c
1609
1610 size_t os::lasterror(char *buf, size_t len) {
1611
1612 if (errno == 0) return 0;
1613
1614 const char *s = ::strerror(errno);
1615 size_t n = ::strlen(s);
1616 if (n >= len) {
1617 n = len - 1;
1618 }
1619 ::strncpy(buf, s, n);
1620 buf[n] = '\0';
1621 return n;
1622 }
1623
1624 intx os::current_thread_id() { return (intx)pthread_self(); }
1625 int os::current_process_id() {
1626
1627 // Under the old linux thread library, linux gives each thread
1628 // its own process id. Because of this each thread will return
1629 // a different pid if this method were to return the result
1630 // of getpid(2). Linux provides no api that returns the pid
1631 // of the launcher thread for the vm. This implementation
1632 // returns a unique pid, the pid of the launcher thread
1633 // that starts the vm 'process'.
1634
1635 // Under the NPTL, getpid() returns the same pid as the
1636 // launcher thread rather than a unique pid per thread.
1637 // Use gettid() if you want the old pre NPTL behaviour.
1638
1639 // if you are looking for the result of a call to getpid() that
1640 // returns a unique pid for the calling thread, then look at the
1641 // OSThread::thread_id() method in osThread_linux.hpp file
1642
1643 return (int)(_initial_pid ? _initial_pid : getpid());
1644 }
1645
1646 // DLL functions
1647
1648 const char* os::dll_file_extension() { return ".so"; }
1649
1650 // This must be hard coded because it's the system's temporary
1651 // directory not the java application's temp directory, ala java.io.tmpdir.
1652 const char* os::get_temp_directory() { return "/tmp"; }
1653
1654 static bool file_exists(const char* filename) {
1655 struct stat statbuf;
1656 if (filename == NULL || strlen(filename) == 0) {
1657 return false;
1658 }
1659 return os::stat(filename, &statbuf) == 0;
1660 }
1661
1662 void os::dll_build_name(char* buffer, size_t buflen,
1663 const char* pname, const char* fname) {
1664 // Copied from libhpi
1665 const size_t pnamelen = pname ? strlen(pname) : 0;
1666
1667 // Quietly truncate on buffer overflow. Should be an error.
1668 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1669 *buffer = '\0';
1670 return;
1671 }
1672
1673 if (pnamelen == 0) {
1674 snprintf(buffer, buflen, "lib%s.so", fname);
1675 } else if (strchr(pname, *os::path_separator()) != NULL) {
1676 int n;
1677 char** pelements = split_path(pname, &n);
1678 for (int i = 0 ; i < n ; i++) {
1679 // Really shouldn't be NULL, but check can't hurt
1680 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1681 continue; // skip the empty path values
1682 }
1683 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1684 if (file_exists(buffer)) {
1685 break;
1686 }
1687 }
1688 // release the storage
1689 for (int i = 0 ; i < n ; i++) {
1690 if (pelements[i] != NULL) {
1691 FREE_C_HEAP_ARRAY(char, pelements[i]);
1692 }
1693 }
1694 if (pelements != NULL) {
1695 FREE_C_HEAP_ARRAY(char*, pelements);
1696 }
1697 } else {
1698 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1699 }
1700 }
1701
1702 const char* os::get_current_directory(char *buf, int buflen) {
1703 return getcwd(buf, buflen);
1704 }
1705
1706 // check if addr is inside libjvm[_g].so
1707 bool os::address_is_in_vm(address addr) {
1708 static address libjvm_base_addr;
1709 Dl_info dlinfo;
1710
1711 if (libjvm_base_addr == NULL) {
1712 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1713 libjvm_base_addr = (address)dlinfo.dli_fbase;
1714 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1715 }
1716
1717 if (dladdr((void *)addr, &dlinfo)) {
1718 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1719 }
1720
1721 return false;
1722 }
1723
1724 bool os::dll_address_to_function_name(address addr, char *buf,
1725 int buflen, int *offset) {
1726 Dl_info dlinfo;
1727
1728 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1729 if (buf != NULL) {
1730 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1731 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1732 }
1733 }
1734 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1735 return true;
1736 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1737 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1738 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) {
1739 return true;
1740 }
1741 }
1742
1743 if (buf != NULL) buf[0] = '\0';
1744 if (offset != NULL) *offset = -1;
1745 return false;
1746 }
1747
1748 struct _address_to_library_name {
1749 address addr; // input : memory address
1750 size_t buflen; // size of fname
1751 char* fname; // output: library name
1752 address base; // library base addr
1753 };
1754
1755 static int address_to_library_name_callback(struct dl_phdr_info *info,
1756 size_t size, void *data) {
1757 int i;
1758 bool found = false;
1759 address libbase = NULL;
1760 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1761
1762 // iterate through all loadable segments
1763 for (i = 0; i < info->dlpi_phnum; i++) {
1764 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1765 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1766 // base address of a library is the lowest address of its loaded
1767 // segments.
1768 if (libbase == NULL || libbase > segbase) {
1769 libbase = segbase;
1770 }
1771 // see if 'addr' is within current segment
1772 if (segbase <= d->addr &&
1773 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1774 found = true;
1775 }
1776 }
1777 }
1778
1779 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1780 // so dll_address_to_library_name() can fall through to use dladdr() which
1781 // can figure out executable name from argv[0].
1782 if (found && info->dlpi_name && info->dlpi_name[0]) {
1783 d->base = libbase;
1784 if (d->fname) {
1785 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1786 }
1787 return 1;
1788 }
1789 return 0;
1790 }
1791
1792 bool os::dll_address_to_library_name(address addr, char* buf,
1793 int buflen, int* offset) {
1794 Dl_info dlinfo;
1795 struct _address_to_library_name data;
1796
1797 // There is a bug in old glibc dladdr() implementation that it could resolve
1798 // to wrong library name if the .so file has a base address != NULL. Here
1799 // we iterate through the program headers of all loaded libraries to find
1800 // out which library 'addr' really belongs to. This workaround can be
1801 // removed once the minimum requirement for glibc is moved to 2.3.x.
1802 data.addr = addr;
1803 data.fname = buf;
1804 data.buflen = buflen;
1805 data.base = NULL;
1806 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1807
1808 if (rslt) {
1809 // buf already contains library name
1810 if (offset) *offset = addr - data.base;
1811 return true;
1812 } else if (dladdr((void*)addr, &dlinfo)){
1813 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1814 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1815 return true;
1816 } else {
1817 if (buf) buf[0] = '\0';
1818 if (offset) *offset = -1;
1819 return false;
1820 }
1821 }
1822
1823 // Loads .dll/.so and
1824 // in case of error it checks if .dll/.so was built for the
1825 // same architecture as Hotspot is running on
1826
1827 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1828 {
1829 void * result= ::dlopen(filename, RTLD_LAZY);
1830 if (result != NULL) {
1831 // Successful loading
1832 return result;
1833 }
1834
1835 Elf32_Ehdr elf_head;
1836
1837 // Read system error message into ebuf
1838 // It may or may not be overwritten below
1839 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1840 ebuf[ebuflen-1]='\0';
1841 int diag_msg_max_length=ebuflen-strlen(ebuf);
1842 char* diag_msg_buf=ebuf+strlen(ebuf);
1843
1844 if (diag_msg_max_length==0) {
1845 // No more space in ebuf for additional diagnostics message
1846 return NULL;
1847 }
1848
1849
1850 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1851
1852 if (file_descriptor < 0) {
1853 // Can't open library, report dlerror() message
1854 return NULL;
1855 }
1856
1857 bool failed_to_read_elf_head=
1858 (sizeof(elf_head)!=
1859 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1860
1861 ::close(file_descriptor);
1862 if (failed_to_read_elf_head) {
1863 // file i/o error - report dlerror() msg
1864 return NULL;
1865 }
1866
1867 typedef struct {
1868 Elf32_Half code; // Actual value as defined in elf.h
1869 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1870 char elf_class; // 32 or 64 bit
1871 char endianess; // MSB or LSB
1872 char* name; // String representation
1873 } arch_t;
1874
1875 #ifndef EM_486
1876 #define EM_486 6 /* Intel 80486 */
1877 #endif
1878
1879 static const arch_t arch_array[]={
1880 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1881 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1882 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1883 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1884 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1885 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1886 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1887 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1888 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1889 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1890 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1891 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1892 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1893 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1894 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1895 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1896 };
1897
1898 #if (defined IA32)
1899 static Elf32_Half running_arch_code=EM_386;
1900 #elif (defined AMD64)
1901 static Elf32_Half running_arch_code=EM_X86_64;
1902 #elif (defined IA64)
1903 static Elf32_Half running_arch_code=EM_IA_64;
1904 #elif (defined __sparc) && (defined _LP64)
1905 static Elf32_Half running_arch_code=EM_SPARCV9;
1906 #elif (defined __sparc) && (!defined _LP64)
1907 static Elf32_Half running_arch_code=EM_SPARC;
1908 #elif (defined __powerpc64__)
1909 static Elf32_Half running_arch_code=EM_PPC64;
1910 #elif (defined __powerpc__)
1911 static Elf32_Half running_arch_code=EM_PPC;
1912 #elif (defined ARM)
1913 static Elf32_Half running_arch_code=EM_ARM;
1914 #elif (defined S390)
1915 static Elf32_Half running_arch_code=EM_S390;
1916 #elif (defined ALPHA)
1917 static Elf32_Half running_arch_code=EM_ALPHA;
1918 #elif (defined MIPSEL)
1919 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1920 #elif (defined PARISC)
1921 static Elf32_Half running_arch_code=EM_PARISC;
1922 #elif (defined MIPS)
1923 static Elf32_Half running_arch_code=EM_MIPS;
1924 #elif (defined M68K)
1925 static Elf32_Half running_arch_code=EM_68K;
1926 #else
1927 #error Method os::dll_load requires that one of following is defined:\
1928 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1929 #endif
1930
1931 // Identify compatability class for VM's architecture and library's architecture
1932 // Obtain string descriptions for architectures
1933
1934 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1935 int running_arch_index=-1;
1936
1937 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1938 if (running_arch_code == arch_array[i].code) {
1939 running_arch_index = i;
1940 }
1941 if (lib_arch.code == arch_array[i].code) {
1942 lib_arch.compat_class = arch_array[i].compat_class;
1943 lib_arch.name = arch_array[i].name;
1944 }
1945 }
1946
1947 assert(running_arch_index != -1,
1948 "Didn't find running architecture code (running_arch_code) in arch_array");
1949 if (running_arch_index == -1) {
1950 // Even though running architecture detection failed
1951 // we may still continue with reporting dlerror() message
1952 return NULL;
1953 }
1954
1955 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1956 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1957 return NULL;
1958 }
1959
1960 #ifndef S390
1961 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1962 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1963 return NULL;
1964 }
1965 #endif // !S390
1966
1967 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1968 if ( lib_arch.name!=NULL ) {
1969 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1970 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1971 lib_arch.name, arch_array[running_arch_index].name);
1972 } else {
1973 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1974 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1975 lib_arch.code,
1976 arch_array[running_arch_index].name);
1977 }
1978 }
1979
1980 return NULL;
1981 }
1982
1983 /*
1984 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1985 * chances are you might want to run the generated bits against glibc-2.0
1986 * libdl.so, so always use locking for any version of glibc.
1987 */
1988 void* os::dll_lookup(void* handle, const char* name) {
1989 pthread_mutex_lock(&dl_mutex);
1990 void* res = dlsym(handle, name);
1991 pthread_mutex_unlock(&dl_mutex);
1992 return res;
1993 }
1994
1995
1996 static bool _print_ascii_file(const char* filename, outputStream* st) {
1997 int fd = ::open(filename, O_RDONLY);
1998 if (fd == -1) {
1999 return false;
2000 }
2001
2002 char buf[32];
2003 int bytes;
2004 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2005 st->print_raw(buf, bytes);
2006 }
2007
2008 ::close(fd);
2009
2010 return true;
2011 }
2012
2013 void os::print_dll_info(outputStream *st) {
2014 st->print_cr("Dynamic libraries:");
2015
2016 char fname[32];
2017 pid_t pid = os::Linux::gettid();
2018
2019 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2020
2021 if (!_print_ascii_file(fname, st)) {
2022 st->print("Can not get library information for pid = %d\n", pid);
2023 }
2024 }
2025
2026
2027 void os::print_os_info(outputStream* st) {
2028 st->print("OS:");
2029
2030 // Try to identify popular distros.
2031 // Most Linux distributions have /etc/XXX-release file, which contains
2032 // the OS version string. Some have more than one /etc/XXX-release file
2033 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2034 // so the order is important.
2035 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2036 !_print_ascii_file("/etc/sun-release", st) &&
2037 !_print_ascii_file("/etc/redhat-release", st) &&
2038 !_print_ascii_file("/etc/SuSE-release", st) &&
2039 !_print_ascii_file("/etc/turbolinux-release", st) &&
2040 !_print_ascii_file("/etc/gentoo-release", st) &&
2041 !_print_ascii_file("/etc/debian_version", st) &&
2042 !_print_ascii_file("/etc/ltib-release", st) &&
2043 !_print_ascii_file("/etc/angstrom-version", st)) {
2044 st->print("Linux");
2045 }
2046 st->cr();
2047
2048 // kernel
2049 st->print("uname:");
2050 struct utsname name;
2051 uname(&name);
2052 st->print(name.sysname); st->print(" ");
2053 st->print(name.release); st->print(" ");
2054 st->print(name.version); st->print(" ");
2055 st->print(name.machine);
2056 st->cr();
2057
2058 // Print warning if unsafe chroot environment detected
2059 if (unsafe_chroot_detected) {
2060 st->print("WARNING!! ");
2061 st->print_cr(unstable_chroot_error);
2062 }
2063
2064 // libc, pthread
2065 st->print("libc:");
2066 st->print(os::Linux::glibc_version()); st->print(" ");
2067 st->print(os::Linux::libpthread_version()); st->print(" ");
2068 if (os::Linux::is_LinuxThreads()) {
2069 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2070 }
2071 st->cr();
2072
2073 // rlimit
2074 st->print("rlimit:");
2075 struct rlimit rlim;
2076
2077 st->print(" STACK ");
2078 getrlimit(RLIMIT_STACK, &rlim);
2079 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2080 else st->print("%uk", rlim.rlim_cur >> 10);
2081
2082 st->print(", CORE ");
2083 getrlimit(RLIMIT_CORE, &rlim);
2084 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2085 else st->print("%uk", rlim.rlim_cur >> 10);
2086
2087 st->print(", NPROC ");
2088 getrlimit(RLIMIT_NPROC, &rlim);
2089 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2090 else st->print("%d", rlim.rlim_cur);
2091
2092 st->print(", NOFILE ");
2093 getrlimit(RLIMIT_NOFILE, &rlim);
2094 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2095 else st->print("%d", rlim.rlim_cur);
2096
2097 st->print(", AS ");
2098 getrlimit(RLIMIT_AS, &rlim);
2099 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2100 else st->print("%uk", rlim.rlim_cur >> 10);
2101 st->cr();
2102
2103 // load average
2104 st->print("load average:");
2105 double loadavg[3];
2106 os::loadavg(loadavg, 3);
2107 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2108 st->cr();
2109
2110 // meminfo
2111 st->print("\n/proc/meminfo:\n");
2112 _print_ascii_file("/proc/meminfo", st);
2113 st->cr();
2114 }
2115
2116 void os::pd_print_cpu_info(outputStream* st) {
2117 st->print("\n/proc/cpuinfo:\n");
2118 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2119 st->print(" <Not Available>");
2120 }
2121 st->cr();
2122 }
2123
2124 void os::print_memory_info(outputStream* st) {
2125
2126 st->print("Memory:");
2127 st->print(" %dk page", os::vm_page_size()>>10);
2128
2129 // values in struct sysinfo are "unsigned long"
2130 struct sysinfo si;
2131 sysinfo(&si);
2132
2133 st->print(", physical " UINT64_FORMAT "k",
2134 os::physical_memory() >> 10);
2135 st->print("(" UINT64_FORMAT "k free)",
2136 os::available_memory() >> 10);
2137 st->print(", swap " UINT64_FORMAT "k",
2138 ((jlong)si.totalswap * si.mem_unit) >> 10);
2139 st->print("(" UINT64_FORMAT "k free)",
2140 ((jlong)si.freeswap * si.mem_unit) >> 10);
2141 st->cr();
2142 }
2143
2144 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2145 // but they're the same for all the linux arch that we support
2146 // and they're the same for solaris but there's no common place to put this.
2147 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2148 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2149 "ILL_COPROC", "ILL_BADSTK" };
2150
2151 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2152 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2153 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2154
2155 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2156
2157 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2158
2159 void os::print_siginfo(outputStream* st, void* siginfo) {
2160 st->print("siginfo:");
2161
2162 const int buflen = 100;
2163 char buf[buflen];
2164 siginfo_t *si = (siginfo_t*)siginfo;
2165 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2166 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2167 st->print("si_errno=%s", buf);
2168 } else {
2169 st->print("si_errno=%d", si->si_errno);
2170 }
2171 const int c = si->si_code;
2172 assert(c > 0, "unexpected si_code");
2173 switch (si->si_signo) {
2174 case SIGILL:
2175 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2176 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2177 break;
2178 case SIGFPE:
2179 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2180 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2181 break;
2182 case SIGSEGV:
2183 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2184 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2185 break;
2186 case SIGBUS:
2187 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2188 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2189 break;
2190 default:
2191 st->print(", si_code=%d", si->si_code);
2192 // no si_addr
2193 }
2194
2195 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2196 UseSharedSpaces) {
2197 FileMapInfo* mapinfo = FileMapInfo::current_info();
2198 if (mapinfo->is_in_shared_space(si->si_addr)) {
2199 st->print("\n\nError accessing class data sharing archive." \
2200 " Mapped file inaccessible during execution, " \
2201 " possible disk/network problem.");
2202 }
2203 }
2204 st->cr();
2205 }
2206
2207
2208 static void print_signal_handler(outputStream* st, int sig,
2209 char* buf, size_t buflen);
2210
2211 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2212 st->print_cr("Signal Handlers:");
2213 print_signal_handler(st, SIGSEGV, buf, buflen);
2214 print_signal_handler(st, SIGBUS , buf, buflen);
2215 print_signal_handler(st, SIGFPE , buf, buflen);
2216 print_signal_handler(st, SIGPIPE, buf, buflen);
2217 print_signal_handler(st, SIGXFSZ, buf, buflen);
2218 print_signal_handler(st, SIGILL , buf, buflen);
2219 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2220 print_signal_handler(st, SR_signum, buf, buflen);
2221 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2222 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2223 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2224 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2225 }
2226
2227 static char saved_jvm_path[MAXPATHLEN] = {0};
2228
2229 // Find the full path to the current module, libjvm.so or libjvm_g.so
2230 void os::jvm_path(char *buf, jint buflen) {
2231 // Error checking.
2232 if (buflen < MAXPATHLEN) {
2233 assert(false, "must use a large-enough buffer");
2234 buf[0] = '\0';
2235 return;
2236 }
2237 // Lazy resolve the path to current module.
2238 if (saved_jvm_path[0] != 0) {
2239 strcpy(buf, saved_jvm_path);
2240 return;
2241 }
2242
2243 char dli_fname[MAXPATHLEN];
2244 bool ret = dll_address_to_library_name(
2245 CAST_FROM_FN_PTR(address, os::jvm_path),
2246 dli_fname, sizeof(dli_fname), NULL);
2247 assert(ret != 0, "cannot locate libjvm");
2248 char *rp = realpath(dli_fname, buf);
2249 if (rp == NULL)
2250 return;
2251
2252 if (Arguments::created_by_gamma_launcher()) {
2253 // Support for the gamma launcher. Typical value for buf is
2254 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2255 // the right place in the string, then assume we are installed in a JDK and
2256 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2257 // up the path so it looks like libjvm.so is installed there (append a
2258 // fake suffix hotspot/libjvm.so).
2259 const char *p = buf + strlen(buf) - 1;
2260 for (int count = 0; p > buf && count < 5; ++count) {
2261 for (--p; p > buf && *p != '/'; --p)
2262 /* empty */ ;
2263 }
2264
2265 if (strncmp(p, "/jre/lib/", 9) != 0) {
2266 // Look for JAVA_HOME in the environment.
2267 char* java_home_var = ::getenv("JAVA_HOME");
2268 if (java_home_var != NULL && java_home_var[0] != 0) {
2269 char* jrelib_p;
2270 int len;
2271
2272 // Check the current module name "libjvm.so" or "libjvm_g.so".
2273 p = strrchr(buf, '/');
2274 assert(strstr(p, "/libjvm") == p, "invalid library name");
2275 p = strstr(p, "_g") ? "_g" : "";
2276
2277 rp = realpath(java_home_var, buf);
2278 if (rp == NULL)
2279 return;
2280
2281 // determine if this is a legacy image or modules image
2282 // modules image doesn't have "jre" subdirectory
2283 len = strlen(buf);
2284 jrelib_p = buf + len;
2285 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2286 if (0 != access(buf, F_OK)) {
2287 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2288 }
2289
2290 if (0 == access(buf, F_OK)) {
2291 // Use current module name "libjvm[_g].so" instead of
2292 // "libjvm"debug_only("_g")".so" since for fastdebug version
2293 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2294 len = strlen(buf);
2295 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2296 } else {
2297 // Go back to path of .so
2298 rp = realpath(dli_fname, buf);
2299 if (rp == NULL)
2300 return;
2301 }
2302 }
2303 }
2304 }
2305
2306 strcpy(saved_jvm_path, buf);
2307 }
2308
2309 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2310 // no prefix required, not even "_"
2311 }
2312
2313 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2314 // no suffix required
2315 }
2316
2317 ////////////////////////////////////////////////////////////////////////////////
2318 // sun.misc.Signal support
2319
2320 static volatile jint sigint_count = 0;
2321
2322 static void
2323 UserHandler(int sig, void *siginfo, void *context) {
2324 // 4511530 - sem_post is serialized and handled by the manager thread. When
2325 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2326 // don't want to flood the manager thread with sem_post requests.
2327 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2328 return;
2329
2330 // Ctrl-C is pressed during error reporting, likely because the error
2331 // handler fails to abort. Let VM die immediately.
2332 if (sig == SIGINT && is_error_reported()) {
2333 os::die();
2334 }
2335
2336 os::signal_notify(sig);
2337 }
2338
2339 void* os::user_handler() {
2340 return CAST_FROM_FN_PTR(void*, UserHandler);
2341 }
2342
2343 extern "C" {
2344 typedef void (*sa_handler_t)(int);
2345 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2346 }
2347
2348 void* os::signal(int signal_number, void* handler) {
2349 struct sigaction sigAct, oldSigAct;
2350
2351 sigfillset(&(sigAct.sa_mask));
2352 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2353 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2354
2355 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2356 // -1 means registration failed
2357 return (void *)-1;
2358 }
2359
2360 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2361 }
2362
2363 void os::signal_raise(int signal_number) {
2364 ::raise(signal_number);
2365 }
2366
2367 /*
2368 * The following code is moved from os.cpp for making this
2369 * code platform specific, which it is by its very nature.
2370 */
2371
2372 // Will be modified when max signal is changed to be dynamic
2373 int os::sigexitnum_pd() {
2374 return NSIG;
2375 }
2376
2377 // a counter for each possible signal value
2378 static volatile jint pending_signals[NSIG+1] = { 0 };
2379
2380 // Linux(POSIX) specific hand shaking semaphore.
2381 static sem_t sig_sem;
2382
2383 void os::signal_init_pd() {
2384 // Initialize signal structures
2385 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2386
2387 // Initialize signal semaphore
2388 ::sem_init(&sig_sem, 0, 0);
2389 }
2390
2391 void os::signal_notify(int sig) {
2392 Atomic::inc(&pending_signals[sig]);
2393 ::sem_post(&sig_sem);
2394 }
2395
2396 static int check_pending_signals(bool wait) {
2397 Atomic::store(0, &sigint_count);
2398 for (;;) {
2399 for (int i = 0; i < NSIG + 1; i++) {
2400 jint n = pending_signals[i];
2401 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2402 return i;
2403 }
2404 }
2405 if (!wait) {
2406 return -1;
2407 }
2408 JavaThread *thread = JavaThread::current();
2409 ThreadBlockInVM tbivm(thread);
2410
2411 bool threadIsSuspended;
2412 do {
2413 thread->set_suspend_equivalent();
2414 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2415 ::sem_wait(&sig_sem);
2416
2417 // were we externally suspended while we were waiting?
2418 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2419 if (threadIsSuspended) {
2420 //
2421 // The semaphore has been incremented, but while we were waiting
2422 // another thread suspended us. We don't want to continue running
2423 // while suspended because that would surprise the thread that
2424 // suspended us.
2425 //
2426 ::sem_post(&sig_sem);
2427
2428 thread->java_suspend_self();
2429 }
2430 } while (threadIsSuspended);
2431 }
2432 }
2433
2434 int os::signal_lookup() {
2435 return check_pending_signals(false);
2436 }
2437
2438 int os::signal_wait() {
2439 return check_pending_signals(true);
2440 }
2441
2442 ////////////////////////////////////////////////////////////////////////////////
2443 // Virtual Memory
2444
2445 int os::vm_page_size() {
2446 // Seems redundant as all get out
2447 assert(os::Linux::page_size() != -1, "must call os::init");
2448 return os::Linux::page_size();
2449 }
2450
2451 // Solaris allocates memory by pages.
2452 int os::vm_allocation_granularity() {
2453 assert(os::Linux::page_size() != -1, "must call os::init");
2454 return os::Linux::page_size();
2455 }
2456
2457 // Rationale behind this function:
2458 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2459 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2460 // samples for JITted code. Here we create private executable mapping over the code cache
2461 // and then we can use standard (well, almost, as mapping can change) way to provide
2462 // info for the reporting script by storing timestamp and location of symbol
2463 void linux_wrap_code(char* base, size_t size) {
2464 static volatile jint cnt = 0;
2465
2466 if (!UseOprofile) {
2467 return;
2468 }
2469
2470 char buf[PATH_MAX+1];
2471 int num = Atomic::add(1, &cnt);
2472
2473 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2474 os::get_temp_directory(), os::current_process_id(), num);
2475 unlink(buf);
2476
2477 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2478
2479 if (fd != -1) {
2480 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2481 if (rv != (off_t)-1) {
2482 if (::write(fd, "", 1) == 1) {
2483 mmap(base, size,
2484 PROT_READ|PROT_WRITE|PROT_EXEC,
2485 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2486 }
2487 }
2488 ::close(fd);
2489 unlink(buf);
2490 }
2491 }
2492
2493 // NOTE: Linux kernel does not really reserve the pages for us.
2494 // All it does is to check if there are enough free pages
2495 // left at the time of mmap(). This could be a potential
2496 // problem.
2497 bool os::commit_memory(char* addr, size_t size, bool exec) {
2498 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2499 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2500 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2501 if (res != (uintptr_t) MAP_FAILED) {
2502 if (UseNUMAInterleaving) {
2503 numa_make_global(addr, size);
2504 }
2505 return true;
2506 }
2507 return false;
2508 }
2509
2510 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2511 #ifndef MAP_HUGETLB
2512 #define MAP_HUGETLB 0x40000
2513 #endif
2514
2515 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2516 #ifndef MADV_HUGEPAGE
2517 #define MADV_HUGEPAGE 14
2518 #endif
2519
2520 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2521 bool exec) {
2522 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2523 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2524 uintptr_t res =
2525 (uintptr_t) ::mmap(addr, size, prot,
2526 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2527 -1, 0);
2528 if (res != (uintptr_t) MAP_FAILED) {
2529 if (UseNUMAInterleaving) {
2530 numa_make_global(addr, size);
2531 }
2532 return true;
2533 }
2534 return false;
2535 }
2536
2537 return commit_memory(addr, size, exec);
2538 }
2539
2540 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2541 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2542 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2543 // be supported or the memory may already be backed by huge pages.
2544 ::madvise(addr, bytes, MADV_HUGEPAGE);
2545 }
2546 }
2547
2548 void os::free_memory(char *addr, size_t bytes) {
2549 commit_memory(addr, bytes, false);
2550 }
2551
2552 void os::numa_make_global(char *addr, size_t bytes) {
2553 Linux::numa_interleave_memory(addr, bytes);
2554 }
2555
2556 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2557 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2558 }
2559
2560 bool os::numa_topology_changed() { return false; }
2561
2562 size_t os::numa_get_groups_num() {
2563 int max_node = Linux::numa_max_node();
2564 return max_node > 0 ? max_node + 1 : 1;
2565 }
2566
2567 int os::numa_get_group_id() {
2568 int cpu_id = Linux::sched_getcpu();
2569 if (cpu_id != -1) {
2570 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2571 if (lgrp_id != -1) {
2572 return lgrp_id;
2573 }
2574 }
2575 return 0;
2576 }
2577
2578 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2579 for (size_t i = 0; i < size; i++) {
2580 ids[i] = i;
2581 }
2582 return size;
2583 }
2584
2585 bool os::get_page_info(char *start, page_info* info) {
2586 return false;
2587 }
2588
2589 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2590 return end;
2591 }
2592
2593
2594 int os::Linux::sched_getcpu_syscall(void) {
2595 unsigned int cpu;
2596 int retval = -1;
2597
2598 #if defined(IA32)
2599 # ifndef SYS_getcpu
2600 # define SYS_getcpu 318
2601 # endif
2602 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2603 #elif defined(AMD64)
2604 // Unfortunately we have to bring all these macros here from vsyscall.h
2605 // to be able to compile on old linuxes.
2606 # define __NR_vgetcpu 2
2607 # define VSYSCALL_START (-10UL << 20)
2608 # define VSYSCALL_SIZE 1024
2609 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2610 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2611 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2612 retval = vgetcpu(&cpu, NULL, NULL);
2613 #endif
2614
2615 return (retval == -1) ? retval : cpu;
2616 }
2617
2618 // Something to do with the numa-aware allocator needs these symbols
2619 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2620 extern "C" JNIEXPORT void numa_error(char *where) { }
2621 extern "C" JNIEXPORT int fork1() { return fork(); }
2622
2623
2624 // If we are running with libnuma version > 2, then we should
2625 // be trying to use symbols with versions 1.1
2626 // If we are running with earlier version, which did not have symbol versions,
2627 // we should use the base version.
2628 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2629 void *f = dlvsym(handle, name, "libnuma_1.1");
2630 if (f == NULL) {
2631 f = dlsym(handle, name);
2632 }
2633 return f;
2634 }
2635
2636 bool os::Linux::libnuma_init() {
2637 // sched_getcpu() should be in libc.
2638 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2639 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2640
2641 // If it's not, try a direct syscall.
2642 if (sched_getcpu() == -1)
2643 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2644
2645 if (sched_getcpu() != -1) { // Does it work?
2646 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2647 if (handle != NULL) {
2648 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2649 libnuma_dlsym(handle, "numa_node_to_cpus")));
2650 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2651 libnuma_dlsym(handle, "numa_max_node")));
2652 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2653 libnuma_dlsym(handle, "numa_available")));
2654 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2655 libnuma_dlsym(handle, "numa_tonode_memory")));
2656 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2657 libnuma_dlsym(handle, "numa_interleave_memory")));
2658
2659
2660 if (numa_available() != -1) {
2661 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2662 // Create a cpu -> node mapping
2663 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2664 rebuild_cpu_to_node_map();
2665 return true;
2666 }
2667 }
2668 }
2669 return false;
2670 }
2671
2672 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2673 // The table is later used in get_node_by_cpu().
2674 void os::Linux::rebuild_cpu_to_node_map() {
2675 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2676 // in libnuma (possible values are starting from 16,
2677 // and continuing up with every other power of 2, but less
2678 // than the maximum number of CPUs supported by kernel), and
2679 // is a subject to change (in libnuma version 2 the requirements
2680 // are more reasonable) we'll just hardcode the number they use
2681 // in the library.
2682 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2683
2684 size_t cpu_num = os::active_processor_count();
2685 size_t cpu_map_size = NCPUS / BitsPerCLong;
2686 size_t cpu_map_valid_size =
2687 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2688
2689 cpu_to_node()->clear();
2690 cpu_to_node()->at_grow(cpu_num - 1);
2691 size_t node_num = numa_get_groups_num();
2692
2693 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2694 for (size_t i = 0; i < node_num; i++) {
2695 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2696 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2697 if (cpu_map[j] != 0) {
2698 for (size_t k = 0; k < BitsPerCLong; k++) {
2699 if (cpu_map[j] & (1UL << k)) {
2700 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2701 }
2702 }
2703 }
2704 }
2705 }
2706 }
2707 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2708 }
2709
2710 int os::Linux::get_node_by_cpu(int cpu_id) {
2711 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2712 return cpu_to_node()->at(cpu_id);
2713 }
2714 return -1;
2715 }
2716
2717 GrowableArray<int>* os::Linux::_cpu_to_node;
2718 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2719 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2720 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2721 os::Linux::numa_available_func_t os::Linux::_numa_available;
2722 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2723 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2724 unsigned long* os::Linux::_numa_all_nodes;
2725
2726 bool os::uncommit_memory(char* addr, size_t size) {
2727 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2728 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2729 return res != (uintptr_t) MAP_FAILED;
2730 }
2731
2732 // Linux uses a growable mapping for the stack, and if the mapping for
2733 // the stack guard pages is not removed when we detach a thread the
2734 // stack cannot grow beyond the pages where the stack guard was
2735 // mapped. If at some point later in the process the stack expands to
2736 // that point, the Linux kernel cannot expand the stack any further
2737 // because the guard pages are in the way, and a segfault occurs.
2738 //
2739 // However, it's essential not to split the stack region by unmapping
2740 // a region (leaving a hole) that's already part of the stack mapping,
2741 // so if the stack mapping has already grown beyond the guard pages at
2742 // the time we create them, we have to truncate the stack mapping.
2743 // So, we need to know the extent of the stack mapping when
2744 // create_stack_guard_pages() is called.
2745
2746 // Find the bounds of the stack mapping. Return true for success.
2747 //
2748 // We only need this for stacks that are growable: at the time of
2749 // writing thread stacks don't use growable mappings (i.e. those
2750 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2751 // only applies to the main thread.
2752
2753 static
2754 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2755
2756 char buf[128];
2757 int fd, sz;
2758
2759 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2760 return false;
2761 }
2762
2763 const char kw[] = "[stack]";
2764 const int kwlen = sizeof(kw)-1;
2765
2766 // Address part of /proc/self/maps couldn't be more than 128 bytes
2767 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2768 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2769 // Extract addresses
2770 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2771 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2772 if (sp >= *bottom && sp <= *top) {
2773 ::close(fd);
2774 return true;
2775 }
2776 }
2777 }
2778 }
2779
2780 ::close(fd);
2781 return false;
2782 }
2783
2784
2785 // If the (growable) stack mapping already extends beyond the point
2786 // where we're going to put our guard pages, truncate the mapping at
2787 // that point by munmap()ping it. This ensures that when we later
2788 // munmap() the guard pages we don't leave a hole in the stack
2789 // mapping. This only affects the main/initial thread, but guard
2790 // against future OS changes
2791 bool os::create_stack_guard_pages(char* addr, size_t size) {
2792 uintptr_t stack_extent, stack_base;
2793 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2794 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2795 assert(os::Linux::is_initial_thread(),
2796 "growable stack in non-initial thread");
2797 if (stack_extent < (uintptr_t)addr)
2798 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2799 }
2800
2801 return os::commit_memory(addr, size);
2802 }
2803
2804 // If this is a growable mapping, remove the guard pages entirely by
2805 // munmap()ping them. If not, just call uncommit_memory(). This only
2806 // affects the main/initial thread, but guard against future OS changes
2807 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2808 uintptr_t stack_extent, stack_base;
2809 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2810 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2811 assert(os::Linux::is_initial_thread(),
2812 "growable stack in non-initial thread");
2813
2814 return ::munmap(addr, size) == 0;
2815 }
2816
2817 return os::uncommit_memory(addr, size);
2818 }
2819
2820 static address _highest_vm_reserved_address = NULL;
2821
2822 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2823 // at 'requested_addr'. If there are existing memory mappings at the same
2824 // location, however, they will be overwritten. If 'fixed' is false,
2825 // 'requested_addr' is only treated as a hint, the return value may or
2826 // may not start from the requested address. Unlike Linux mmap(), this
2827 // function returns NULL to indicate failure.
2828 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2829 char * addr;
2830 int flags;
2831
2832 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2833 if (fixed) {
2834 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2835 flags |= MAP_FIXED;
2836 }
2837
2838 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2839 // to PROT_EXEC if executable when we commit the page.
2840 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2841 flags, -1, 0);
2842
2843 if (addr != MAP_FAILED) {
2844 // anon_mmap() should only get called during VM initialization,
2845 // don't need lock (actually we can skip locking even it can be called
2846 // from multiple threads, because _highest_vm_reserved_address is just a
2847 // hint about the upper limit of non-stack memory regions.)
2848 if ((address)addr + bytes > _highest_vm_reserved_address) {
2849 _highest_vm_reserved_address = (address)addr + bytes;
2850 }
2851 }
2852
2853 return addr == MAP_FAILED ? NULL : addr;
2854 }
2855
2856 // Don't update _highest_vm_reserved_address, because there might be memory
2857 // regions above addr + size. If so, releasing a memory region only creates
2858 // a hole in the address space, it doesn't help prevent heap-stack collision.
2859 //
2860 static int anon_munmap(char * addr, size_t size) {
2861 return ::munmap(addr, size) == 0;
2862 }
2863
2864 char* os::reserve_memory(size_t bytes, char* requested_addr,
2865 size_t alignment_hint) {
2866 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2867 }
2868
2869 bool os::release_memory(char* addr, size_t size) {
2870 return anon_munmap(addr, size);
2871 }
2872
2873 static address highest_vm_reserved_address() {
2874 return _highest_vm_reserved_address;
2875 }
2876
2877 static bool linux_mprotect(char* addr, size_t size, int prot) {
2878 // Linux wants the mprotect address argument to be page aligned.
2879 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2880
2881 // According to SUSv3, mprotect() should only be used with mappings
2882 // established by mmap(), and mmap() always maps whole pages. Unaligned
2883 // 'addr' likely indicates problem in the VM (e.g. trying to change
2884 // protection of malloc'ed or statically allocated memory). Check the
2885 // caller if you hit this assert.
2886 assert(addr == bottom, "sanity check");
2887
2888 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2889 return ::mprotect(bottom, size, prot) == 0;
2890 }
2891
2892 // Set protections specified
2893 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2894 bool is_committed) {
2895 unsigned int p = 0;
2896 switch (prot) {
2897 case MEM_PROT_NONE: p = PROT_NONE; break;
2898 case MEM_PROT_READ: p = PROT_READ; break;
2899 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2900 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2901 default:
2902 ShouldNotReachHere();
2903 }
2904 // is_committed is unused.
2905 return linux_mprotect(addr, bytes, p);
2906 }
2907
2908 bool os::guard_memory(char* addr, size_t size) {
2909 return linux_mprotect(addr, size, PROT_NONE);
2910 }
2911
2912 bool os::unguard_memory(char* addr, size_t size) {
2913 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2914 }
2915
2916 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2917 bool result = false;
2918 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2919 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2920 -1, 0);
2921
2922 if (p != (void *) -1) {
2923 // We don't know if this really is a huge page or not.
2924 FILE *fp = fopen("/proc/self/maps", "r");
2925 if (fp) {
2926 while (!feof(fp)) {
2927 char chars[257];
2928 long x = 0;
2929 if (fgets(chars, sizeof(chars), fp)) {
2930 if (sscanf(chars, "%lx-%*x", &x) == 1
2931 && x == (long)p) {
2932 if (strstr (chars, "hugepage")) {
2933 result = true;
2934 break;
2935 }
2936 }
2937 }
2938 }
2939 fclose(fp);
2940 }
2941 munmap (p, page_size);
2942 if (result)
2943 return true;
2944 }
2945
2946 if (warn) {
2947 warning("HugeTLBFS is not supported by the operating system.");
2948 }
2949
2950 return result;
2951 }
2952
2953 /*
2954 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2955 *
2956 * From the coredump_filter documentation:
2957 *
2958 * - (bit 0) anonymous private memory
2959 * - (bit 1) anonymous shared memory
2960 * - (bit 2) file-backed private memory
2961 * - (bit 3) file-backed shared memory
2962 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2963 * effective only if the bit 2 is cleared)
2964 * - (bit 5) hugetlb private memory
2965 * - (bit 6) hugetlb shared memory
2966 */
2967 static void set_coredump_filter(void) {
2968 FILE *f;
2969 long cdm;
2970
2971 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2972 return;
2973 }
2974
2975 if (fscanf(f, "%lx", &cdm) != 1) {
2976 fclose(f);
2977 return;
2978 }
2979
2980 rewind(f);
2981
2982 if ((cdm & LARGEPAGES_BIT) == 0) {
2983 cdm |= LARGEPAGES_BIT;
2984 fprintf(f, "%#lx", cdm);
2985 }
2986
2987 fclose(f);
2988 }
2989
2990 // Large page support
2991
2992 static size_t _large_page_size = 0;
2993
2994 void os::large_page_init() {
2995 if (!UseLargePages) {
2996 UseHugeTLBFS = false;
2997 UseSHM = false;
2998 return;
2999 }
3000
3001 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
3002 // If UseLargePages is specified on the command line try both methods,
3003 // if it's default, then try only HugeTLBFS.
3004 if (FLAG_IS_DEFAULT(UseLargePages)) {
3005 UseHugeTLBFS = true;
3006 } else {
3007 UseHugeTLBFS = UseSHM = true;
3008 }
3009 }
3010
3011 if (LargePageSizeInBytes) {
3012 _large_page_size = LargePageSizeInBytes;
3013 } else {
3014 // large_page_size on Linux is used to round up heap size. x86 uses either
3015 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3016 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3017 // page as large as 256M.
3018 //
3019 // Here we try to figure out page size by parsing /proc/meminfo and looking
3020 // for a line with the following format:
3021 // Hugepagesize: 2048 kB
3022 //
3023 // If we can't determine the value (e.g. /proc is not mounted, or the text
3024 // format has been changed), we'll use the largest page size supported by
3025 // the processor.
3026
3027 #ifndef ZERO
3028 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3029 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3030 #endif // ZERO
3031
3032 FILE *fp = fopen("/proc/meminfo", "r");
3033 if (fp) {
3034 while (!feof(fp)) {
3035 int x = 0;
3036 char buf[16];
3037 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3038 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3039 _large_page_size = x * K;
3040 break;
3041 }
3042 } else {
3043 // skip to next line
3044 for (;;) {
3045 int ch = fgetc(fp);
3046 if (ch == EOF || ch == (int)'\n') break;
3047 }
3048 }
3049 }
3050 fclose(fp);
3051 }
3052 }
3053
3054 // print a warning if any large page related flag is specified on command line
3055 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3056
3057 const size_t default_page_size = (size_t)Linux::page_size();
3058 if (_large_page_size > default_page_size) {
3059 _page_sizes[0] = _large_page_size;
3060 _page_sizes[1] = default_page_size;
3061 _page_sizes[2] = 0;
3062 }
3063 UseHugeTLBFS = UseHugeTLBFS &&
3064 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3065
3066 if (UseHugeTLBFS)
3067 UseSHM = false;
3068
3069 UseLargePages = UseHugeTLBFS || UseSHM;
3070
3071 set_coredump_filter();
3072 }
3073
3074 #ifndef SHM_HUGETLB
3075 #define SHM_HUGETLB 04000
3076 #endif
3077
3078 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3079 // "exec" is passed in but not used. Creating the shared image for
3080 // the code cache doesn't have an SHM_X executable permission to check.
3081 assert(UseLargePages && UseSHM, "only for SHM large pages");
3082
3083 key_t key = IPC_PRIVATE;
3084 char *addr;
3085
3086 bool warn_on_failure = UseLargePages &&
3087 (!FLAG_IS_DEFAULT(UseLargePages) ||
3088 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3089 );
3090 char msg[128];
3091
3092 // Create a large shared memory region to attach to based on size.
3093 // Currently, size is the total size of the heap
3094 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3095 if (shmid == -1) {
3096 // Possible reasons for shmget failure:
3097 // 1. shmmax is too small for Java heap.
3098 // > check shmmax value: cat /proc/sys/kernel/shmmax
3099 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3100 // 2. not enough large page memory.
3101 // > check available large pages: cat /proc/meminfo
3102 // > increase amount of large pages:
3103 // echo new_value > /proc/sys/vm/nr_hugepages
3104 // Note 1: different Linux may use different name for this property,
3105 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3106 // Note 2: it's possible there's enough physical memory available but
3107 // they are so fragmented after a long run that they can't
3108 // coalesce into large pages. Try to reserve large pages when
3109 // the system is still "fresh".
3110 if (warn_on_failure) {
3111 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3112 warning(msg);
3113 }
3114 return NULL;
3115 }
3116
3117 // attach to the region
3118 addr = (char*)shmat(shmid, req_addr, 0);
3119 int err = errno;
3120
3121 // Remove shmid. If shmat() is successful, the actual shared memory segment
3122 // will be deleted when it's detached by shmdt() or when the process
3123 // terminates. If shmat() is not successful this will remove the shared
3124 // segment immediately.
3125 shmctl(shmid, IPC_RMID, NULL);
3126
3127 if ((intptr_t)addr == -1) {
3128 if (warn_on_failure) {
3129 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3130 warning(msg);
3131 }
3132 return NULL;
3133 }
3134
3135 if ((addr != NULL) && UseNUMAInterleaving) {
3136 numa_make_global(addr, bytes);
3137 }
3138
3139 return addr;
3140 }
3141
3142 bool os::release_memory_special(char* base, size_t bytes) {
3143 // detaching the SHM segment will also delete it, see reserve_memory_special()
3144 int rslt = shmdt(base);
3145 return rslt == 0;
3146 }
3147
3148 size_t os::large_page_size() {
3149 return _large_page_size;
3150 }
3151
3152 // HugeTLBFS allows application to commit large page memory on demand;
3153 // with SysV SHM the entire memory region must be allocated as shared
3154 // memory.
3155 bool os::can_commit_large_page_memory() {
3156 return UseHugeTLBFS;
3157 }
3158
3159 bool os::can_execute_large_page_memory() {
3160 return UseHugeTLBFS;
3161 }
3162
3163 // Reserve memory at an arbitrary address, only if that area is
3164 // available (and not reserved for something else).
3165
3166 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3167 const int max_tries = 10;
3168 char* base[max_tries];
3169 size_t size[max_tries];
3170 const size_t gap = 0x000000;
3171
3172 // Assert only that the size is a multiple of the page size, since
3173 // that's all that mmap requires, and since that's all we really know
3174 // about at this low abstraction level. If we need higher alignment,
3175 // we can either pass an alignment to this method or verify alignment
3176 // in one of the methods further up the call chain. See bug 5044738.
3177 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3178
3179 // Repeatedly allocate blocks until the block is allocated at the
3180 // right spot. Give up after max_tries. Note that reserve_memory() will
3181 // automatically update _highest_vm_reserved_address if the call is
3182 // successful. The variable tracks the highest memory address every reserved
3183 // by JVM. It is used to detect heap-stack collision if running with
3184 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3185 // space than needed, it could confuse the collision detecting code. To
3186 // solve the problem, save current _highest_vm_reserved_address and
3187 // calculate the correct value before return.
3188 address old_highest = _highest_vm_reserved_address;
3189
3190 // Linux mmap allows caller to pass an address as hint; give it a try first,
3191 // if kernel honors the hint then we can return immediately.
3192 char * addr = anon_mmap(requested_addr, bytes, false);
3193 if (addr == requested_addr) {
3194 return requested_addr;
3195 }
3196
3197 if (addr != NULL) {
3198 // mmap() is successful but it fails to reserve at the requested address
3199 anon_munmap(addr, bytes);
3200 }
3201
3202 int i;
3203 for (i = 0; i < max_tries; ++i) {
3204 base[i] = reserve_memory(bytes);
3205
3206 if (base[i] != NULL) {
3207 // Is this the block we wanted?
3208 if (base[i] == requested_addr) {
3209 size[i] = bytes;
3210 break;
3211 }
3212
3213 // Does this overlap the block we wanted? Give back the overlapped
3214 // parts and try again.
3215
3216 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3217 if (top_overlap >= 0 && top_overlap < bytes) {
3218 unmap_memory(base[i], top_overlap);
3219 base[i] += top_overlap;
3220 size[i] = bytes - top_overlap;
3221 } else {
3222 size_t bottom_overlap = base[i] + bytes - requested_addr;
3223 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3224 unmap_memory(requested_addr, bottom_overlap);
3225 size[i] = bytes - bottom_overlap;
3226 } else {
3227 size[i] = bytes;
3228 }
3229 }
3230 }
3231 }
3232
3233 // Give back the unused reserved pieces.
3234
3235 for (int j = 0; j < i; ++j) {
3236 if (base[j] != NULL) {
3237 unmap_memory(base[j], size[j]);
3238 }
3239 }
3240
3241 if (i < max_tries) {
3242 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3243 return requested_addr;
3244 } else {
3245 _highest_vm_reserved_address = old_highest;
3246 return NULL;
3247 }
3248 }
3249
3250 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3251 return ::read(fd, buf, nBytes);
3252 }
3253
3254 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3255 // Solaris uses poll(), linux uses park().
3256 // Poll() is likely a better choice, assuming that Thread.interrupt()
3257 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3258 // SIGSEGV, see 4355769.
3259
3260 const int NANOSECS_PER_MILLISECS = 1000000;
3261
3262 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3263 assert(thread == Thread::current(), "thread consistency check");
3264
3265 ParkEvent * const slp = thread->_SleepEvent ;
3266 slp->reset() ;
3267 OrderAccess::fence() ;
3268
3269 if (interruptible) {
3270 jlong prevtime = javaTimeNanos();
3271
3272 for (;;) {
3273 if (os::is_interrupted(thread, true)) {
3274 return OS_INTRPT;
3275 }
3276
3277 jlong newtime = javaTimeNanos();
3278
3279 if (newtime - prevtime < 0) {
3280 // time moving backwards, should only happen if no monotonic clock
3281 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3282 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3283 } else {
3284 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3285 }
3286
3287 if(millis <= 0) {
3288 return OS_OK;
3289 }
3290
3291 prevtime = newtime;
3292
3293 {
3294 assert(thread->is_Java_thread(), "sanity check");
3295 JavaThread *jt = (JavaThread *) thread;
3296 ThreadBlockInVM tbivm(jt);
3297 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3298
3299 jt->set_suspend_equivalent();
3300 // cleared by handle_special_suspend_equivalent_condition() or
3301 // java_suspend_self() via check_and_wait_while_suspended()
3302
3303 slp->park(millis);
3304
3305 // were we externally suspended while we were waiting?
3306 jt->check_and_wait_while_suspended();
3307 }
3308 }
3309 } else {
3310 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3311 jlong prevtime = javaTimeNanos();
3312
3313 for (;;) {
3314 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3315 // the 1st iteration ...
3316 jlong newtime = javaTimeNanos();
3317
3318 if (newtime - prevtime < 0) {
3319 // time moving backwards, should only happen if no monotonic clock
3320 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3321 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3322 } else {
3323 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3324 }
3325
3326 if(millis <= 0) break ;
3327
3328 prevtime = newtime;
3329 slp->park(millis);
3330 }
3331 return OS_OK ;
3332 }
3333 }
3334
3335 int os::naked_sleep() {
3336 // %% make the sleep time an integer flag. for now use 1 millisec.
3337 return os::sleep(Thread::current(), 1, false);
3338 }
3339
3340 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3341 void os::infinite_sleep() {
3342 while (true) { // sleep forever ...
3343 ::sleep(100); // ... 100 seconds at a time
3344 }
3345 }
3346
3347 // Used to convert frequent JVM_Yield() to nops
3348 bool os::dont_yield() {
3349 return DontYieldALot;
3350 }
3351
3352 void os::yield() {
3353 sched_yield();
3354 }
3355
3356 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3357
3358 void os::yield_all(int attempts) {
3359 // Yields to all threads, including threads with lower priorities
3360 // Threads on Linux are all with same priority. The Solaris style
3361 // os::yield_all() with nanosleep(1ms) is not necessary.
3362 sched_yield();
3363 }
3364
3365 // Called from the tight loops to possibly influence time-sharing heuristics
3366 void os::loop_breaker(int attempts) {
3367 os::yield_all(attempts);
3368 }
3369
3370 ////////////////////////////////////////////////////////////////////////////////
3371 // thread priority support
3372
3373 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3374 // only supports dynamic priority, static priority must be zero. For real-time
3375 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3376 // However, for large multi-threaded applications, SCHED_RR is not only slower
3377 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3378 // of 5 runs - Sep 2005).
3379 //
3380 // The following code actually changes the niceness of kernel-thread/LWP. It
3381 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3382 // not the entire user process, and user level threads are 1:1 mapped to kernel
3383 // threads. It has always been the case, but could change in the future. For
3384 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3385 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3386
3387 int os::java_to_os_priority[MaxPriority + 1] = {
3388 19, // 0 Entry should never be used
3389
3390 4, // 1 MinPriority
3391 3, // 2
3392 2, // 3
3393
3394 1, // 4
3395 0, // 5 NormPriority
3396 -1, // 6
3397
3398 -2, // 7
3399 -3, // 8
3400 -4, // 9 NearMaxPriority
3401
3402 -5 // 10 MaxPriority
3403 };
3404
3405 static int prio_init() {
3406 if (ThreadPriorityPolicy == 1) {
3407 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3408 // if effective uid is not root. Perhaps, a more elegant way of doing
3409 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3410 if (geteuid() != 0) {
3411 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3412 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3413 }
3414 ThreadPriorityPolicy = 0;
3415 }
3416 }
3417 return 0;
3418 }
3419
3420 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3421 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3422
3423 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3424 return (ret == 0) ? OS_OK : OS_ERR;
3425 }
3426
3427 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3428 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3429 *priority_ptr = java_to_os_priority[NormPriority];
3430 return OS_OK;
3431 }
3432
3433 errno = 0;
3434 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3435 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3436 }
3437
3438 // Hint to the underlying OS that a task switch would not be good.
3439 // Void return because it's a hint and can fail.
3440 void os::hint_no_preempt() {}
3441
3442 ////////////////////////////////////////////////////////////////////////////////
3443 // suspend/resume support
3444
3445 // the low-level signal-based suspend/resume support is a remnant from the
3446 // old VM-suspension that used to be for java-suspension, safepoints etc,
3447 // within hotspot. Now there is a single use-case for this:
3448 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3449 // that runs in the watcher thread.
3450 // The remaining code is greatly simplified from the more general suspension
3451 // code that used to be used.
3452 //
3453 // The protocol is quite simple:
3454 // - suspend:
3455 // - sends a signal to the target thread
3456 // - polls the suspend state of the osthread using a yield loop
3457 // - target thread signal handler (SR_handler) sets suspend state
3458 // and blocks in sigsuspend until continued
3459 // - resume:
3460 // - sets target osthread state to continue
3461 // - sends signal to end the sigsuspend loop in the SR_handler
3462 //
3463 // Note that the SR_lock plays no role in this suspend/resume protocol.
3464 //
3465
3466 static void resume_clear_context(OSThread *osthread) {
3467 osthread->set_ucontext(NULL);
3468 osthread->set_siginfo(NULL);
3469
3470 // notify the suspend action is completed, we have now resumed
3471 osthread->sr.clear_suspended();
3472 }
3473
3474 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3475 osthread->set_ucontext(context);
3476 osthread->set_siginfo(siginfo);
3477 }
3478
3479 //
3480 // Handler function invoked when a thread's execution is suspended or
3481 // resumed. We have to be careful that only async-safe functions are
3482 // called here (Note: most pthread functions are not async safe and
3483 // should be avoided.)
3484 //
3485 // Note: sigwait() is a more natural fit than sigsuspend() from an
3486 // interface point of view, but sigwait() prevents the signal hander
3487 // from being run. libpthread would get very confused by not having
3488 // its signal handlers run and prevents sigwait()'s use with the
3489 // mutex granting granting signal.
3490 //
3491 // Currently only ever called on the VMThread
3492 //
3493 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3494 // Save and restore errno to avoid confusing native code with EINTR
3495 // after sigsuspend.
3496 int old_errno = errno;
3497
3498 Thread* thread = Thread::current();
3499 OSThread* osthread = thread->osthread();
3500 assert(thread->is_VM_thread(), "Must be VMThread");
3501 // read current suspend action
3502 int action = osthread->sr.suspend_action();
3503 if (action == SR_SUSPEND) {
3504 suspend_save_context(osthread, siginfo, context);
3505
3506 // Notify the suspend action is about to be completed. do_suspend()
3507 // waits until SR_SUSPENDED is set and then returns. We will wait
3508 // here for a resume signal and that completes the suspend-other
3509 // action. do_suspend/do_resume is always called as a pair from
3510 // the same thread - so there are no races
3511
3512 // notify the caller
3513 osthread->sr.set_suspended();
3514
3515 sigset_t suspend_set; // signals for sigsuspend()
3516
3517 // get current set of blocked signals and unblock resume signal
3518 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3519 sigdelset(&suspend_set, SR_signum);
3520
3521 // wait here until we are resumed
3522 do {
3523 sigsuspend(&suspend_set);
3524 // ignore all returns until we get a resume signal
3525 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3526
3527 resume_clear_context(osthread);
3528
3529 } else {
3530 assert(action == SR_CONTINUE, "unexpected sr action");
3531 // nothing special to do - just leave the handler
3532 }
3533
3534 errno = old_errno;
3535 }
3536
3537
3538 static int SR_initialize() {
3539 struct sigaction act;
3540 char *s;
3541 /* Get signal number to use for suspend/resume */
3542 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3543 int sig = ::strtol(s, 0, 10);
3544 if (sig > 0 || sig < _NSIG) {
3545 SR_signum = sig;
3546 }
3547 }
3548
3549 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3550 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3551
3552 sigemptyset(&SR_sigset);
3553 sigaddset(&SR_sigset, SR_signum);
3554
3555 /* Set up signal handler for suspend/resume */
3556 act.sa_flags = SA_RESTART|SA_SIGINFO;
3557 act.sa_handler = (void (*)(int)) SR_handler;
3558
3559 // SR_signum is blocked by default.
3560 // 4528190 - We also need to block pthread restart signal (32 on all
3561 // supported Linux platforms). Note that LinuxThreads need to block
3562 // this signal for all threads to work properly. So we don't have
3563 // to use hard-coded signal number when setting up the mask.
3564 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3565
3566 if (sigaction(SR_signum, &act, 0) == -1) {
3567 return -1;
3568 }
3569
3570 // Save signal flag
3571 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3572 return 0;
3573 }
3574
3575 static int SR_finalize() {
3576 return 0;
3577 }
3578
3579
3580 // returns true on success and false on error - really an error is fatal
3581 // but this seems the normal response to library errors
3582 static bool do_suspend(OSThread* osthread) {
3583 // mark as suspended and send signal
3584 osthread->sr.set_suspend_action(SR_SUSPEND);
3585 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3586 assert_status(status == 0, status, "pthread_kill");
3587
3588 // check status and wait until notified of suspension
3589 if (status == 0) {
3590 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3591 os::yield_all(i);
3592 }
3593 osthread->sr.set_suspend_action(SR_NONE);
3594 return true;
3595 }
3596 else {
3597 osthread->sr.set_suspend_action(SR_NONE);
3598 return false;
3599 }
3600 }
3601
3602 static void do_resume(OSThread* osthread) {
3603 assert(osthread->sr.is_suspended(), "thread should be suspended");
3604 osthread->sr.set_suspend_action(SR_CONTINUE);
3605
3606 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3607 assert_status(status == 0, status, "pthread_kill");
3608 // check status and wait unit notified of resumption
3609 if (status == 0) {
3610 for (int i = 0; osthread->sr.is_suspended(); i++) {
3611 os::yield_all(i);
3612 }
3613 }
3614 osthread->sr.set_suspend_action(SR_NONE);
3615 }
3616
3617 ////////////////////////////////////////////////////////////////////////////////
3618 // interrupt support
3619
3620 void os::interrupt(Thread* thread) {
3621 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3622 "possibility of dangling Thread pointer");
3623
3624 OSThread* osthread = thread->osthread();
3625
3626 if (!osthread->interrupted()) {
3627 osthread->set_interrupted(true);
3628 // More than one thread can get here with the same value of osthread,
3629 // resulting in multiple notifications. We do, however, want the store
3630 // to interrupted() to be visible to other threads before we execute unpark().
3631 OrderAccess::fence();
3632 ParkEvent * const slp = thread->_SleepEvent ;
3633 if (slp != NULL) slp->unpark() ;
3634 }
3635
3636 // For JSR166. Unpark even if interrupt status already was set
3637 if (thread->is_Java_thread())
3638 ((JavaThread*)thread)->parker()->unpark();
3639
3640 ParkEvent * ev = thread->_ParkEvent ;
3641 if (ev != NULL) ev->unpark() ;
3642
3643 }
3644
3645 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3646 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3647 "possibility of dangling Thread pointer");
3648
3649 OSThread* osthread = thread->osthread();
3650
3651 bool interrupted = osthread->interrupted();
3652
3653 if (interrupted && clear_interrupted) {
3654 osthread->set_interrupted(false);
3655 // consider thread->_SleepEvent->reset() ... optional optimization
3656 }
3657
3658 return interrupted;
3659 }
3660
3661 ///////////////////////////////////////////////////////////////////////////////////
3662 // signal handling (except suspend/resume)
3663
3664 // This routine may be used by user applications as a "hook" to catch signals.
3665 // The user-defined signal handler must pass unrecognized signals to this
3666 // routine, and if it returns true (non-zero), then the signal handler must
3667 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3668 // routine will never retun false (zero), but instead will execute a VM panic
3669 // routine kill the process.
3670 //
3671 // If this routine returns false, it is OK to call it again. This allows
3672 // the user-defined signal handler to perform checks either before or after
3673 // the VM performs its own checks. Naturally, the user code would be making
3674 // a serious error if it tried to handle an exception (such as a null check
3675 // or breakpoint) that the VM was generating for its own correct operation.
3676 //
3677 // This routine may recognize any of the following kinds of signals:
3678 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3679 // It should be consulted by handlers for any of those signals.
3680 //
3681 // The caller of this routine must pass in the three arguments supplied
3682 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3683 // field of the structure passed to sigaction(). This routine assumes that
3684 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3685 //
3686 // Note that the VM will print warnings if it detects conflicting signal
3687 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3688 //
3689 extern "C" JNIEXPORT int
3690 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3691 void* ucontext, int abort_if_unrecognized);
3692
3693 void signalHandler(int sig, siginfo_t* info, void* uc) {
3694 assert(info != NULL && uc != NULL, "it must be old kernel");
3695 JVM_handle_linux_signal(sig, info, uc, true);
3696 }
3697
3698
3699 // This boolean allows users to forward their own non-matching signals
3700 // to JVM_handle_linux_signal, harmlessly.
3701 bool os::Linux::signal_handlers_are_installed = false;
3702
3703 // For signal-chaining
3704 struct sigaction os::Linux::sigact[MAXSIGNUM];
3705 unsigned int os::Linux::sigs = 0;
3706 bool os::Linux::libjsig_is_loaded = false;
3707 typedef struct sigaction *(*get_signal_t)(int);
3708 get_signal_t os::Linux::get_signal_action = NULL;
3709
3710 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3711 struct sigaction *actp = NULL;
3712
3713 if (libjsig_is_loaded) {
3714 // Retrieve the old signal handler from libjsig
3715 actp = (*get_signal_action)(sig);
3716 }
3717 if (actp == NULL) {
3718 // Retrieve the preinstalled signal handler from jvm
3719 actp = get_preinstalled_handler(sig);
3720 }
3721
3722 return actp;
3723 }
3724
3725 static bool call_chained_handler(struct sigaction *actp, int sig,
3726 siginfo_t *siginfo, void *context) {
3727 // Call the old signal handler
3728 if (actp->sa_handler == SIG_DFL) {
3729 // It's more reasonable to let jvm treat it as an unexpected exception
3730 // instead of taking the default action.
3731 return false;
3732 } else if (actp->sa_handler != SIG_IGN) {
3733 if ((actp->sa_flags & SA_NODEFER) == 0) {
3734 // automaticlly block the signal
3735 sigaddset(&(actp->sa_mask), sig);
3736 }
3737
3738 sa_handler_t hand;
3739 sa_sigaction_t sa;
3740 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3741 // retrieve the chained handler
3742 if (siginfo_flag_set) {
3743 sa = actp->sa_sigaction;
3744 } else {
3745 hand = actp->sa_handler;
3746 }
3747
3748 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3749 actp->sa_handler = SIG_DFL;
3750 }
3751
3752 // try to honor the signal mask
3753 sigset_t oset;
3754 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3755
3756 // call into the chained handler
3757 if (siginfo_flag_set) {
3758 (*sa)(sig, siginfo, context);
3759 } else {
3760 (*hand)(sig);
3761 }
3762
3763 // restore the signal mask
3764 pthread_sigmask(SIG_SETMASK, &oset, 0);
3765 }
3766 // Tell jvm's signal handler the signal is taken care of.
3767 return true;
3768 }
3769
3770 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3771 bool chained = false;
3772 // signal-chaining
3773 if (UseSignalChaining) {
3774 struct sigaction *actp = get_chained_signal_action(sig);
3775 if (actp != NULL) {
3776 chained = call_chained_handler(actp, sig, siginfo, context);
3777 }
3778 }
3779 return chained;
3780 }
3781
3782 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3783 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3784 return &sigact[sig];
3785 }
3786 return NULL;
3787 }
3788
3789 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3790 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3791 sigact[sig] = oldAct;
3792 sigs |= (unsigned int)1 << sig;
3793 }
3794
3795 // for diagnostic
3796 int os::Linux::sigflags[MAXSIGNUM];
3797
3798 int os::Linux::get_our_sigflags(int sig) {
3799 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3800 return sigflags[sig];
3801 }
3802
3803 void os::Linux::set_our_sigflags(int sig, int flags) {
3804 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3805 sigflags[sig] = flags;
3806 }
3807
3808 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3809 // Check for overwrite.
3810 struct sigaction oldAct;
3811 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3812
3813 void* oldhand = oldAct.sa_sigaction
3814 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3815 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3816 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3817 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3818 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3819 if (AllowUserSignalHandlers || !set_installed) {
3820 // Do not overwrite; user takes responsibility to forward to us.
3821 return;
3822 } else if (UseSignalChaining) {
3823 // save the old handler in jvm
3824 save_preinstalled_handler(sig, oldAct);
3825 // libjsig also interposes the sigaction() call below and saves the
3826 // old sigaction on it own.
3827 } else {
3828 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3829 "%#lx for signal %d.", (long)oldhand, sig));
3830 }
3831 }
3832
3833 struct sigaction sigAct;
3834 sigfillset(&(sigAct.sa_mask));
3835 sigAct.sa_handler = SIG_DFL;
3836 if (!set_installed) {
3837 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3838 } else {
3839 sigAct.sa_sigaction = signalHandler;
3840 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3841 }
3842 // Save flags, which are set by ours
3843 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3844 sigflags[sig] = sigAct.sa_flags;
3845
3846 int ret = sigaction(sig, &sigAct, &oldAct);
3847 assert(ret == 0, "check");
3848
3849 void* oldhand2 = oldAct.sa_sigaction
3850 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3851 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3852 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3853 }
3854
3855 // install signal handlers for signals that HotSpot needs to
3856 // handle in order to support Java-level exception handling.
3857
3858 void os::Linux::install_signal_handlers() {
3859 if (!signal_handlers_are_installed) {
3860 signal_handlers_are_installed = true;
3861
3862 // signal-chaining
3863 typedef void (*signal_setting_t)();
3864 signal_setting_t begin_signal_setting = NULL;
3865 signal_setting_t end_signal_setting = NULL;
3866 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3867 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3868 if (begin_signal_setting != NULL) {
3869 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3870 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3871 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3872 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3873 libjsig_is_loaded = true;
3874 assert(UseSignalChaining, "should enable signal-chaining");
3875 }
3876 if (libjsig_is_loaded) {
3877 // Tell libjsig jvm is setting signal handlers
3878 (*begin_signal_setting)();
3879 }
3880
3881 set_signal_handler(SIGSEGV, true);
3882 set_signal_handler(SIGPIPE, true);
3883 set_signal_handler(SIGBUS, true);
3884 set_signal_handler(SIGILL, true);
3885 set_signal_handler(SIGFPE, true);
3886 set_signal_handler(SIGXFSZ, true);
3887
3888 if (libjsig_is_loaded) {
3889 // Tell libjsig jvm finishes setting signal handlers
3890 (*end_signal_setting)();
3891 }
3892
3893 // We don't activate signal checker if libjsig is in place, we trust ourselves
3894 // and if UserSignalHandler is installed all bets are off
3895 if (CheckJNICalls) {
3896 if (libjsig_is_loaded) {
3897 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3898 check_signals = false;
3899 }
3900 if (AllowUserSignalHandlers) {
3901 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3902 check_signals = false;
3903 }
3904 }
3905 }
3906 }
3907
3908 // This is the fastest way to get thread cpu time on Linux.
3909 // Returns cpu time (user+sys) for any thread, not only for current.
3910 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3911 // It might work on 2.6.10+ with a special kernel/glibc patch.
3912 // For reference, please, see IEEE Std 1003.1-2004:
3913 // http://www.unix.org/single_unix_specification
3914
3915 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3916 struct timespec tp;
3917 int rc = os::Linux::clock_gettime(clockid, &tp);
3918 assert(rc == 0, "clock_gettime is expected to return 0 code");
3919
3920 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3921 }
3922
3923 /////
3924 // glibc on Linux platform uses non-documented flag
3925 // to indicate, that some special sort of signal
3926 // trampoline is used.
3927 // We will never set this flag, and we should
3928 // ignore this flag in our diagnostic
3929 #ifdef SIGNIFICANT_SIGNAL_MASK
3930 #undef SIGNIFICANT_SIGNAL_MASK
3931 #endif
3932 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3933
3934 static const char* get_signal_handler_name(address handler,
3935 char* buf, int buflen) {
3936 int offset;
3937 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3938 if (found) {
3939 // skip directory names
3940 const char *p1, *p2;
3941 p1 = buf;
3942 size_t len = strlen(os::file_separator());
3943 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3944 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3945 } else {
3946 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3947 }
3948 return buf;
3949 }
3950
3951 static void print_signal_handler(outputStream* st, int sig,
3952 char* buf, size_t buflen) {
3953 struct sigaction sa;
3954
3955 sigaction(sig, NULL, &sa);
3956
3957 // See comment for SIGNIFICANT_SIGNAL_MASK define
3958 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3959
3960 st->print("%s: ", os::exception_name(sig, buf, buflen));
3961
3962 address handler = (sa.sa_flags & SA_SIGINFO)
3963 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3964 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3965
3966 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3967 st->print("SIG_DFL");
3968 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3969 st->print("SIG_IGN");
3970 } else {
3971 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3972 }
3973
3974 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3975
3976 address rh = VMError::get_resetted_sighandler(sig);
3977 // May be, handler was resetted by VMError?
3978 if(rh != NULL) {
3979 handler = rh;
3980 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3981 }
3982
3983 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3984
3985 // Check: is it our handler?
3986 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3987 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3988 // It is our signal handler
3989 // check for flags, reset system-used one!
3990 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3991 st->print(
3992 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3993 os::Linux::get_our_sigflags(sig));
3994 }
3995 }
3996 st->cr();
3997 }
3998
3999
4000 #define DO_SIGNAL_CHECK(sig) \
4001 if (!sigismember(&check_signal_done, sig)) \
4002 os::Linux::check_signal_handler(sig)
4003
4004 // This method is a periodic task to check for misbehaving JNI applications
4005 // under CheckJNI, we can add any periodic checks here
4006
4007 void os::run_periodic_checks() {
4008
4009 if (check_signals == false) return;
4010
4011 // SEGV and BUS if overridden could potentially prevent
4012 // generation of hs*.log in the event of a crash, debugging
4013 // such a case can be very challenging, so we absolutely
4014 // check the following for a good measure:
4015 DO_SIGNAL_CHECK(SIGSEGV);
4016 DO_SIGNAL_CHECK(SIGILL);
4017 DO_SIGNAL_CHECK(SIGFPE);
4018 DO_SIGNAL_CHECK(SIGBUS);
4019 DO_SIGNAL_CHECK(SIGPIPE);
4020 DO_SIGNAL_CHECK(SIGXFSZ);
4021
4022
4023 // ReduceSignalUsage allows the user to override these handlers
4024 // see comments at the very top and jvm_solaris.h
4025 if (!ReduceSignalUsage) {
4026 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4027 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4028 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4029 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4030 }
4031
4032 DO_SIGNAL_CHECK(SR_signum);
4033 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4034 }
4035
4036 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4037
4038 static os_sigaction_t os_sigaction = NULL;
4039
4040 void os::Linux::check_signal_handler(int sig) {
4041 char buf[O_BUFLEN];
4042 address jvmHandler = NULL;
4043
4044
4045 struct sigaction act;
4046 if (os_sigaction == NULL) {
4047 // only trust the default sigaction, in case it has been interposed
4048 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4049 if (os_sigaction == NULL) return;
4050 }
4051
4052 os_sigaction(sig, (struct sigaction*)NULL, &act);
4053
4054
4055 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4056
4057 address thisHandler = (act.sa_flags & SA_SIGINFO)
4058 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4059 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4060
4061
4062 switch(sig) {
4063 case SIGSEGV:
4064 case SIGBUS:
4065 case SIGFPE:
4066 case SIGPIPE:
4067 case SIGILL:
4068 case SIGXFSZ:
4069 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4070 break;
4071
4072 case SHUTDOWN1_SIGNAL:
4073 case SHUTDOWN2_SIGNAL:
4074 case SHUTDOWN3_SIGNAL:
4075 case BREAK_SIGNAL:
4076 jvmHandler = (address)user_handler();
4077 break;
4078
4079 case INTERRUPT_SIGNAL:
4080 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4081 break;
4082
4083 default:
4084 if (sig == SR_signum) {
4085 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4086 } else {
4087 return;
4088 }
4089 break;
4090 }
4091
4092 if (thisHandler != jvmHandler) {
4093 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4094 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4095 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4096 // No need to check this sig any longer
4097 sigaddset(&check_signal_done, sig);
4098 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4099 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4100 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4101 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4102 // No need to check this sig any longer
4103 sigaddset(&check_signal_done, sig);
4104 }
4105
4106 // Dump all the signal
4107 if (sigismember(&check_signal_done, sig)) {
4108 print_signal_handlers(tty, buf, O_BUFLEN);
4109 }
4110 }
4111
4112 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4113
4114 extern bool signal_name(int signo, char* buf, size_t len);
4115
4116 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4117 if (0 < exception_code && exception_code <= SIGRTMAX) {
4118 // signal
4119 if (!signal_name(exception_code, buf, size)) {
4120 jio_snprintf(buf, size, "SIG%d", exception_code);
4121 }
4122 return buf;
4123 } else {
4124 return NULL;
4125 }
4126 }
4127
4128 // this is called _before_ the most of global arguments have been parsed
4129 void os::init(void) {
4130 char dummy; /* used to get a guess on initial stack address */
4131 // first_hrtime = gethrtime();
4132
4133 // With LinuxThreads the JavaMain thread pid (primordial thread)
4134 // is different than the pid of the java launcher thread.
4135 // So, on Linux, the launcher thread pid is passed to the VM
4136 // via the sun.java.launcher.pid property.
4137 // Use this property instead of getpid() if it was correctly passed.
4138 // See bug 6351349.
4139 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4140
4141 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4142
4143 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4144
4145 init_random(1234567);
4146
4147 ThreadCritical::initialize();
4148
4149 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4150 if (Linux::page_size() == -1) {
4151 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4152 strerror(errno)));
4153 }
4154 init_page_sizes((size_t) Linux::page_size());
4155
4156 Linux::initialize_system_info();
4157
4158 // main_thread points to the aboriginal thread
4159 Linux::_main_thread = pthread_self();
4160
4161 Linux::clock_init();
4162 initial_time_count = os::elapsed_counter();
4163 pthread_mutex_init(&dl_mutex, NULL);
4164 }
4165
4166 // To install functions for atexit system call
4167 extern "C" {
4168 static void perfMemory_exit_helper() {
4169 perfMemory_exit();
4170 }
4171 }
4172
4173 // this is called _after_ the global arguments have been parsed
4174 jint os::init_2(void)
4175 {
4176 Linux::fast_thread_clock_init();
4177
4178 // Allocate a single page and mark it as readable for safepoint polling
4179 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4180 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4181
4182 os::set_polling_page( polling_page );
4183
4184 #ifndef PRODUCT
4185 if(Verbose && PrintMiscellaneous)
4186 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4187 #endif
4188
4189 if (!UseMembar) {
4190 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4191 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4192 os::set_memory_serialize_page( mem_serialize_page );
4193
4194 #ifndef PRODUCT
4195 if(Verbose && PrintMiscellaneous)
4196 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4197 #endif
4198 }
4199
4200 os::large_page_init();
4201
4202 // initialize suspend/resume support - must do this before signal_sets_init()
4203 if (SR_initialize() != 0) {
4204 perror("SR_initialize failed");
4205 return JNI_ERR;
4206 }
4207
4208 Linux::signal_sets_init();
4209 Linux::install_signal_handlers();
4210
4211 // Check minimum allowable stack size for thread creation and to initialize
4212 // the java system classes, including StackOverflowError - depends on page
4213 // size. Add a page for compiler2 recursion in main thread.
4214 // Add in 2*BytesPerWord times page size to account for VM stack during
4215 // class initialization depending on 32 or 64 bit VM.
4216 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4217 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4218 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4219
4220 size_t threadStackSizeInBytes = ThreadStackSize * K;
4221 if (threadStackSizeInBytes != 0 &&
4222 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4223 tty->print_cr("\nThe stack size specified is too small, "
4224 "Specify at least %dk",
4225 os::Linux::min_stack_allowed/ K);
4226 return JNI_ERR;
4227 }
4228
4229 // Make the stack size a multiple of the page size so that
4230 // the yellow/red zones can be guarded.
4231 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4232 vm_page_size()));
4233
4234 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4235
4236 Linux::libpthread_init();
4237 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4238 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4239 Linux::glibc_version(), Linux::libpthread_version(),
4240 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4241 }
4242
4243 if (UseNUMA) {
4244 if (!Linux::libnuma_init()) {
4245 UseNUMA = false;
4246 } else {
4247 if ((Linux::numa_max_node() < 1)) {
4248 // There's only one node(they start from 0), disable NUMA.
4249 UseNUMA = false;
4250 }
4251 }
4252 // With SHM large pages we cannot uncommit a page, so there's not way
4253 // we can make the adaptive lgrp chunk resizing work. If the user specified
4254 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4255 // disable adaptive resizing.
4256 if (UseNUMA && UseLargePages && UseSHM) {
4257 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4258 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4259 UseLargePages = false;
4260 } else {
4261 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4262 UseAdaptiveSizePolicy = false;
4263 UseAdaptiveNUMAChunkSizing = false;
4264 }
4265 } else {
4266 UseNUMA = false;
4267 }
4268 }
4269 if (!UseNUMA && ForceNUMA) {
4270 UseNUMA = true;
4271 }
4272 }
4273
4274 if (MaxFDLimit) {
4275 // set the number of file descriptors to max. print out error
4276 // if getrlimit/setrlimit fails but continue regardless.
4277 struct rlimit nbr_files;
4278 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4279 if (status != 0) {
4280 if (PrintMiscellaneous && (Verbose || WizardMode))
4281 perror("os::init_2 getrlimit failed");
4282 } else {
4283 nbr_files.rlim_cur = nbr_files.rlim_max;
4284 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4285 if (status != 0) {
4286 if (PrintMiscellaneous && (Verbose || WizardMode))
4287 perror("os::init_2 setrlimit failed");
4288 }
4289 }
4290 }
4291
4292 // Initialize lock used to serialize thread creation (see os::create_thread)
4293 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4294
4295 // at-exit methods are called in the reverse order of their registration.
4296 // atexit functions are called on return from main or as a result of a
4297 // call to exit(3C). There can be only 32 of these functions registered
4298 // and atexit() does not set errno.
4299
4300 if (PerfAllowAtExitRegistration) {
4301 // only register atexit functions if PerfAllowAtExitRegistration is set.
4302 // atexit functions can be delayed until process exit time, which
4303 // can be problematic for embedded VM situations. Embedded VMs should
4304 // call DestroyJavaVM() to assure that VM resources are released.
4305
4306 // note: perfMemory_exit_helper atexit function may be removed in
4307 // the future if the appropriate cleanup code can be added to the
4308 // VM_Exit VMOperation's doit method.
4309 if (atexit(perfMemory_exit_helper) != 0) {
4310 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4311 }
4312 }
4313
4314 // initialize thread priority policy
4315 prio_init();
4316
4317 return JNI_OK;
4318 }
4319
4320 // this is called at the end of vm_initialization
4321 void os::init_3(void)
4322 {
4323 #ifdef JAVASE_EMBEDDED
4324 // Start the MemNotifyThread
4325 if (LowMemoryProtection) {
4326 MemNotifyThread::start();
4327 }
4328 return;
4329 #endif
4330 }
4331
4332 // Mark the polling page as unreadable
4333 void os::make_polling_page_unreadable(void) {
4334 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4335 fatal("Could not disable polling page");
4336 };
4337
4338 // Mark the polling page as readable
4339 void os::make_polling_page_readable(void) {
4340 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4341 fatal("Could not enable polling page");
4342 }
4343 };
4344
4345 int os::active_processor_count() {
4346 // Linux doesn't yet have a (official) notion of processor sets,
4347 // so just return the number of online processors.
4348 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4349 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4350 return online_cpus;
4351 }
4352
4353 bool os::distribute_processes(uint length, uint* distribution) {
4354 // Not yet implemented.
4355 return false;
4356 }
4357
4358 bool os::bind_to_processor(uint processor_id) {
4359 // Not yet implemented.
4360 return false;
4361 }
4362
4363 ///
4364
4365 // Suspends the target using the signal mechanism and then grabs the PC before
4366 // resuming the target. Used by the flat-profiler only
4367 ExtendedPC os::get_thread_pc(Thread* thread) {
4368 // Make sure that it is called by the watcher for the VMThread
4369 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4370 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4371
4372 ExtendedPC epc;
4373
4374 OSThread* osthread = thread->osthread();
4375 if (do_suspend(osthread)) {
4376 if (osthread->ucontext() != NULL) {
4377 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4378 } else {
4379 // NULL context is unexpected, double-check this is the VMThread
4380 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4381 }
4382 do_resume(osthread);
4383 }
4384 // failure means pthread_kill failed for some reason - arguably this is
4385 // a fatal problem, but such problems are ignored elsewhere
4386
4387 return epc;
4388 }
4389
4390 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4391 {
4392 if (is_NPTL()) {
4393 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4394 } else {
4395 #ifndef IA64
4396 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4397 // word back to default 64bit precision if condvar is signaled. Java
4398 // wants 53bit precision. Save and restore current value.
4399 int fpu = get_fpu_control_word();
4400 #endif // IA64
4401 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4402 #ifndef IA64
4403 set_fpu_control_word(fpu);
4404 #endif // IA64
4405 return status;
4406 }
4407 }
4408
4409 ////////////////////////////////////////////////////////////////////////////////
4410 // debug support
4411
4412 static address same_page(address x, address y) {
4413 int page_bits = -os::vm_page_size();
4414 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4415 return x;
4416 else if (x > y)
4417 return (address)(intptr_t(y) | ~page_bits) + 1;
4418 else
4419 return (address)(intptr_t(y) & page_bits);
4420 }
4421
4422 bool os::find(address addr, outputStream* st) {
4423 Dl_info dlinfo;
4424 memset(&dlinfo, 0, sizeof(dlinfo));
4425 if (dladdr(addr, &dlinfo)) {
4426 st->print(PTR_FORMAT ": ", addr);
4427 if (dlinfo.dli_sname != NULL) {
4428 st->print("%s+%#x", dlinfo.dli_sname,
4429 addr - (intptr_t)dlinfo.dli_saddr);
4430 } else if (dlinfo.dli_fname) {
4431 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4432 } else {
4433 st->print("<absolute address>");
4434 }
4435 if (dlinfo.dli_fname) {
4436 st->print(" in %s", dlinfo.dli_fname);
4437 }
4438 if (dlinfo.dli_fbase) {
4439 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4440 }
4441 st->cr();
4442
4443 if (Verbose) {
4444 // decode some bytes around the PC
4445 address begin = same_page(addr-40, addr);
4446 address end = same_page(addr+40, addr);
4447 address lowest = (address) dlinfo.dli_sname;
4448 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4449 if (begin < lowest) begin = lowest;
4450 Dl_info dlinfo2;
4451 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4452 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4453 end = (address) dlinfo2.dli_saddr;
4454 Disassembler::decode(begin, end, st);
4455 }
4456 return true;
4457 }
4458 return false;
4459 }
4460
4461 ////////////////////////////////////////////////////////////////////////////////
4462 // misc
4463
4464 // This does not do anything on Linux. This is basically a hook for being
4465 // able to use structured exception handling (thread-local exception filters)
4466 // on, e.g., Win32.
4467 void
4468 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4469 JavaCallArguments* args, Thread* thread) {
4470 f(value, method, args, thread);
4471 }
4472
4473 void os::print_statistics() {
4474 }
4475
4476 int os::message_box(const char* title, const char* message) {
4477 int i;
4478 fdStream err(defaultStream::error_fd());
4479 for (i = 0; i < 78; i++) err.print_raw("=");
4480 err.cr();
4481 err.print_raw_cr(title);
4482 for (i = 0; i < 78; i++) err.print_raw("-");
4483 err.cr();
4484 err.print_raw_cr(message);
4485 for (i = 0; i < 78; i++) err.print_raw("=");
4486 err.cr();
4487
4488 char buf[16];
4489 // Prevent process from exiting upon "read error" without consuming all CPU
4490 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4491
4492 return buf[0] == 'y' || buf[0] == 'Y';
4493 }
4494
4495 int os::stat(const char *path, struct stat *sbuf) {
4496 char pathbuf[MAX_PATH];
4497 if (strlen(path) > MAX_PATH - 1) {
4498 errno = ENAMETOOLONG;
4499 return -1;
4500 }
4501 os::native_path(strcpy(pathbuf, path));
4502 return ::stat(pathbuf, sbuf);
4503 }
4504
4505 bool os::check_heap(bool force) {
4506 return true;
4507 }
4508
4509 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4510 return ::vsnprintf(buf, count, format, args);
4511 }
4512
4513 // Is a (classpath) directory empty?
4514 bool os::dir_is_empty(const char* path) {
4515 DIR *dir = NULL;
4516 struct dirent *ptr;
4517
4518 dir = opendir(path);
4519 if (dir == NULL) return true;
4520
4521 /* Scan the directory */
4522 bool result = true;
4523 char buf[sizeof(struct dirent) + MAX_PATH];
4524 while (result && (ptr = ::readdir(dir)) != NULL) {
4525 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4526 result = false;
4527 }
4528 }
4529 closedir(dir);
4530 return result;
4531 }
4532
4533 // This code originates from JDK's sysOpen and open64_w
4534 // from src/solaris/hpi/src/system_md.c
4535
4536 #ifndef O_DELETE
4537 #define O_DELETE 0x10000
4538 #endif
4539
4540 // Open a file. Unlink the file immediately after open returns
4541 // if the specified oflag has the O_DELETE flag set.
4542 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4543
4544 int os::open(const char *path, int oflag, int mode) {
4545
4546 if (strlen(path) > MAX_PATH - 1) {
4547 errno = ENAMETOOLONG;
4548 return -1;
4549 }
4550 int fd;
4551 int o_delete = (oflag & O_DELETE);
4552 oflag = oflag & ~O_DELETE;
4553
4554 fd = ::open64(path, oflag, mode);
4555 if (fd == -1) return -1;
4556
4557 //If the open succeeded, the file might still be a directory
4558 {
4559 struct stat64 buf64;
4560 int ret = ::fstat64(fd, &buf64);
4561 int st_mode = buf64.st_mode;
4562
4563 if (ret != -1) {
4564 if ((st_mode & S_IFMT) == S_IFDIR) {
4565 errno = EISDIR;
4566 ::close(fd);
4567 return -1;
4568 }
4569 } else {
4570 ::close(fd);
4571 return -1;
4572 }
4573 }
4574
4575 /*
4576 * All file descriptors that are opened in the JVM and not
4577 * specifically destined for a subprocess should have the
4578 * close-on-exec flag set. If we don't set it, then careless 3rd
4579 * party native code might fork and exec without closing all
4580 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4581 * UNIXProcess.c), and this in turn might:
4582 *
4583 * - cause end-of-file to fail to be detected on some file
4584 * descriptors, resulting in mysterious hangs, or
4585 *
4586 * - might cause an fopen in the subprocess to fail on a system
4587 * suffering from bug 1085341.
4588 *
4589 * (Yes, the default setting of the close-on-exec flag is a Unix
4590 * design flaw)
4591 *
4592 * See:
4593 * 1085341: 32-bit stdio routines should support file descriptors >255
4594 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4595 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4596 */
4597 #ifdef FD_CLOEXEC
4598 {
4599 int flags = ::fcntl(fd, F_GETFD);
4600 if (flags != -1)
4601 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4602 }
4603 #endif
4604
4605 if (o_delete != 0) {
4606 ::unlink(path);
4607 }
4608 return fd;
4609 }
4610
4611
4612 // create binary file, rewriting existing file if required
4613 int os::create_binary_file(const char* path, bool rewrite_existing) {
4614 int oflags = O_WRONLY | O_CREAT;
4615 if (!rewrite_existing) {
4616 oflags |= O_EXCL;
4617 }
4618 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4619 }
4620
4621 // return current position of file pointer
4622 jlong os::current_file_offset(int fd) {
4623 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4624 }
4625
4626 // move file pointer to the specified offset
4627 jlong os::seek_to_file_offset(int fd, jlong offset) {
4628 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4629 }
4630
4631 // This code originates from JDK's sysAvailable
4632 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4633
4634 int os::available(int fd, jlong *bytes) {
4635 jlong cur, end;
4636 int mode;
4637 struct stat64 buf64;
4638
4639 if (::fstat64(fd, &buf64) >= 0) {
4640 mode = buf64.st_mode;
4641 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4642 /*
4643 * XXX: is the following call interruptible? If so, this might
4644 * need to go through the INTERRUPT_IO() wrapper as for other
4645 * blocking, interruptible calls in this file.
4646 */
4647 int n;
4648 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4649 *bytes = n;
4650 return 1;
4651 }
4652 }
4653 }
4654 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4655 return 0;
4656 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4657 return 0;
4658 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4659 return 0;
4660 }
4661 *bytes = end - cur;
4662 return 1;
4663 }
4664
4665 int os::socket_available(int fd, jint *pbytes) {
4666 // Linux doc says EINTR not returned, unlike Solaris
4667 int ret = ::ioctl(fd, FIONREAD, pbytes);
4668
4669 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4670 // is expected to return 0 on failure and 1 on success to the jdk.
4671 return (ret < 0) ? 0 : 1;
4672 }
4673
4674 // Map a block of memory.
4675 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4676 char *addr, size_t bytes, bool read_only,
4677 bool allow_exec) {
4678 int prot;
4679 int flags;
4680
4681 if (read_only) {
4682 prot = PROT_READ;
4683 flags = MAP_SHARED;
4684 } else {
4685 prot = PROT_READ | PROT_WRITE;
4686 flags = MAP_PRIVATE;
4687 }
4688
4689 if (allow_exec) {
4690 prot |= PROT_EXEC;
4691 }
4692
4693 if (addr != NULL) {
4694 flags |= MAP_FIXED;
4695 }
4696
4697 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4698 fd, file_offset);
4699 if (mapped_address == MAP_FAILED) {
4700 return NULL;
4701 }
4702 return mapped_address;
4703 }
4704
4705
4706 // Remap a block of memory.
4707 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4708 char *addr, size_t bytes, bool read_only,
4709 bool allow_exec) {
4710 // same as map_memory() on this OS
4711 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4712 allow_exec);
4713 }
4714
4715
4716 // Unmap a block of memory.
4717 bool os::unmap_memory(char* addr, size_t bytes) {
4718 return munmap(addr, bytes) == 0;
4719 }
4720
4721 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4722
4723 static clockid_t thread_cpu_clockid(Thread* thread) {
4724 pthread_t tid = thread->osthread()->pthread_id();
4725 clockid_t clockid;
4726
4727 // Get thread clockid
4728 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4729 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4730 return clockid;
4731 }
4732
4733 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4734 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4735 // of a thread.
4736 //
4737 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4738 // the fast estimate available on the platform.
4739
4740 jlong os::current_thread_cpu_time() {
4741 if (os::Linux::supports_fast_thread_cpu_time()) {
4742 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4743 } else {
4744 // return user + sys since the cost is the same
4745 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4746 }
4747 }
4748
4749 jlong os::thread_cpu_time(Thread* thread) {
4750 // consistent with what current_thread_cpu_time() returns
4751 if (os::Linux::supports_fast_thread_cpu_time()) {
4752 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4753 } else {
4754 return slow_thread_cpu_time(thread, true /* user + sys */);
4755 }
4756 }
4757
4758 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4759 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4760 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4761 } else {
4762 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4763 }
4764 }
4765
4766 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4767 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4768 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4769 } else {
4770 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4771 }
4772 }
4773
4774 //
4775 // -1 on error.
4776 //
4777
4778 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4779 static bool proc_pid_cpu_avail = true;
4780 static bool proc_task_unchecked = true;
4781 static const char *proc_stat_path = "/proc/%d/stat";
4782 pid_t tid = thread->osthread()->thread_id();
4783 int i;
4784 char *s;
4785 char stat[2048];
4786 int statlen;
4787 char proc_name[64];
4788 int count;
4789 long sys_time, user_time;
4790 char string[64];
4791 char cdummy;
4792 int idummy;
4793 long ldummy;
4794 FILE *fp;
4795
4796 // We first try accessing /proc/<pid>/cpu since this is faster to
4797 // process. If this file is not present (linux kernels 2.5 and above)
4798 // then we open /proc/<pid>/stat.
4799 if ( proc_pid_cpu_avail ) {
4800 sprintf(proc_name, "/proc/%d/cpu", tid);
4801 fp = fopen(proc_name, "r");
4802 if ( fp != NULL ) {
4803 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4804 fclose(fp);
4805 if ( count != 3 ) return -1;
4806
4807 if (user_sys_cpu_time) {
4808 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4809 } else {
4810 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4811 }
4812 }
4813 else proc_pid_cpu_avail = false;
4814 }
4815
4816 // The /proc/<tid>/stat aggregates per-process usage on
4817 // new Linux kernels 2.6+ where NPTL is supported.
4818 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4819 // See bug 6328462.
4820 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4821 // and possibly in some other cases, so we check its availability.
4822 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4823 // This is executed only once
4824 proc_task_unchecked = false;
4825 fp = fopen("/proc/self/task", "r");
4826 if (fp != NULL) {
4827 proc_stat_path = "/proc/self/task/%d/stat";
4828 fclose(fp);
4829 }
4830 }
4831
4832 sprintf(proc_name, proc_stat_path, tid);
4833 fp = fopen(proc_name, "r");
4834 if ( fp == NULL ) return -1;
4835 statlen = fread(stat, 1, 2047, fp);
4836 stat[statlen] = '\0';
4837 fclose(fp);
4838
4839 // Skip pid and the command string. Note that we could be dealing with
4840 // weird command names, e.g. user could decide to rename java launcher
4841 // to "java 1.4.2 :)", then the stat file would look like
4842 // 1234 (java 1.4.2 :)) R ... ...
4843 // We don't really need to know the command string, just find the last
4844 // occurrence of ")" and then start parsing from there. See bug 4726580.
4845 s = strrchr(stat, ')');
4846 i = 0;
4847 if (s == NULL ) return -1;
4848
4849 // Skip blank chars
4850 do s++; while (isspace(*s));
4851
4852 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4853 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4854 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4855 &user_time, &sys_time);
4856 if ( count != 13 ) return -1;
4857 if (user_sys_cpu_time) {
4858 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4859 } else {
4860 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4861 }
4862 }
4863
4864 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4865 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4866 info_ptr->may_skip_backward = false; // elapsed time not wall time
4867 info_ptr->may_skip_forward = false; // elapsed time not wall time
4868 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4869 }
4870
4871 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4872 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4873 info_ptr->may_skip_backward = false; // elapsed time not wall time
4874 info_ptr->may_skip_forward = false; // elapsed time not wall time
4875 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4876 }
4877
4878 bool os::is_thread_cpu_time_supported() {
4879 return true;
4880 }
4881
4882 // System loadavg support. Returns -1 if load average cannot be obtained.
4883 // Linux doesn't yet have a (official) notion of processor sets,
4884 // so just return the system wide load average.
4885 int os::loadavg(double loadavg[], int nelem) {
4886 return ::getloadavg(loadavg, nelem);
4887 }
4888
4889 void os::pause() {
4890 char filename[MAX_PATH];
4891 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4892 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4893 } else {
4894 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4895 }
4896
4897 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4898 if (fd != -1) {
4899 struct stat buf;
4900 ::close(fd);
4901 while (::stat(filename, &buf) == 0) {
4902 (void)::poll(NULL, 0, 100);
4903 }
4904 } else {
4905 jio_fprintf(stderr,
4906 "Could not open pause file '%s', continuing immediately.\n", filename);
4907 }
4908 }
4909
4910
4911 // Refer to the comments in os_solaris.cpp park-unpark.
4912 //
4913 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4914 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4915 // For specifics regarding the bug see GLIBC BUGID 261237 :
4916 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4917 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4918 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4919 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4920 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4921 // and monitorenter when we're using 1-0 locking. All those operations may result in
4922 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4923 // of libpthread avoids the problem, but isn't practical.
4924 //
4925 // Possible remedies:
4926 //
4927 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4928 // This is palliative and probabilistic, however. If the thread is preempted
4929 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4930 // than the minimum period may have passed, and the abstime may be stale (in the
4931 // past) resultin in a hang. Using this technique reduces the odds of a hang
4932 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4933 //
4934 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4935 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4936 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4937 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4938 // thread.
4939 //
4940 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4941 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4942 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4943 // This also works well. In fact it avoids kernel-level scalability impediments
4944 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4945 // timers in a graceful fashion.
4946 //
4947 // 4. When the abstime value is in the past it appears that control returns
4948 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4949 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4950 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4951 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4952 // It may be possible to avoid reinitialization by checking the return
4953 // value from pthread_cond_timedwait(). In addition to reinitializing the
4954 // condvar we must establish the invariant that cond_signal() is only called
4955 // within critical sections protected by the adjunct mutex. This prevents
4956 // cond_signal() from "seeing" a condvar that's in the midst of being
4957 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4958 // desirable signal-after-unlock optimization that avoids futile context switching.
4959 //
4960 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4961 // structure when a condvar is used or initialized. cond_destroy() would
4962 // release the helper structure. Our reinitialize-after-timedwait fix
4963 // put excessive stress on malloc/free and locks protecting the c-heap.
4964 //
4965 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4966 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4967 // and only enabling the work-around for vulnerable environments.
4968
4969 // utility to compute the abstime argument to timedwait:
4970 // millis is the relative timeout time
4971 // abstime will be the absolute timeout time
4972 // TODO: replace compute_abstime() with unpackTime()
4973
4974 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4975 if (millis < 0) millis = 0;
4976 struct timeval now;
4977 int status = gettimeofday(&now, NULL);
4978 assert(status == 0, "gettimeofday");
4979 jlong seconds = millis / 1000;
4980 millis %= 1000;
4981 if (seconds > 50000000) { // see man cond_timedwait(3T)
4982 seconds = 50000000;
4983 }
4984 abstime->tv_sec = now.tv_sec + seconds;
4985 long usec = now.tv_usec + millis * 1000;
4986 if (usec >= 1000000) {
4987 abstime->tv_sec += 1;
4988 usec -= 1000000;
4989 }
4990 abstime->tv_nsec = usec * 1000;
4991 return abstime;
4992 }
4993
4994
4995 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4996 // Conceptually TryPark() should be equivalent to park(0).
4997
4998 int os::PlatformEvent::TryPark() {
4999 for (;;) {
5000 const int v = _Event ;
5001 guarantee ((v == 0) || (v == 1), "invariant") ;
5002 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5003 }
5004 }
5005
5006 void os::PlatformEvent::park() { // AKA "down()"
5007 // Invariant: Only the thread associated with the Event/PlatformEvent
5008 // may call park().
5009 // TODO: assert that _Assoc != NULL or _Assoc == Self
5010 int v ;
5011 for (;;) {
5012 v = _Event ;
5013 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5014 }
5015 guarantee (v >= 0, "invariant") ;
5016 if (v == 0) {
5017 // Do this the hard way by blocking ...
5018 int status = pthread_mutex_lock(_mutex);
5019 assert_status(status == 0, status, "mutex_lock");
5020 guarantee (_nParked == 0, "invariant") ;
5021 ++ _nParked ;
5022 while (_Event < 0) {
5023 status = pthread_cond_wait(_cond, _mutex);
5024 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5025 // Treat this the same as if the wait was interrupted
5026 if (status == ETIME) { status = EINTR; }
5027 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5028 }
5029 -- _nParked ;
5030
5031 // In theory we could move the ST of 0 into _Event past the unlock(),
5032 // but then we'd need a MEMBAR after the ST.
5033 _Event = 0 ;
5034 status = pthread_mutex_unlock(_mutex);
5035 assert_status(status == 0, status, "mutex_unlock");
5036 }
5037 guarantee (_Event >= 0, "invariant") ;
5038 }
5039
5040 int os::PlatformEvent::park(jlong millis) {
5041 guarantee (_nParked == 0, "invariant") ;
5042
5043 int v ;
5044 for (;;) {
5045 v = _Event ;
5046 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5047 }
5048 guarantee (v >= 0, "invariant") ;
5049 if (v != 0) return OS_OK ;
5050
5051 // We do this the hard way, by blocking the thread.
5052 // Consider enforcing a minimum timeout value.
5053 struct timespec abst;
5054 compute_abstime(&abst, millis);
5055
5056 int ret = OS_TIMEOUT;
5057 int status = pthread_mutex_lock(_mutex);
5058 assert_status(status == 0, status, "mutex_lock");
5059 guarantee (_nParked == 0, "invariant") ;
5060 ++_nParked ;
5061
5062 // Object.wait(timo) will return because of
5063 // (a) notification
5064 // (b) timeout
5065 // (c) thread.interrupt
5066 //
5067 // Thread.interrupt and object.notify{All} both call Event::set.
5068 // That is, we treat thread.interrupt as a special case of notification.
5069 // The underlying Solaris implementation, cond_timedwait, admits
5070 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5071 // JVM from making those visible to Java code. As such, we must
5072 // filter out spurious wakeups. We assume all ETIME returns are valid.
5073 //
5074 // TODO: properly differentiate simultaneous notify+interrupt.
5075 // In that case, we should propagate the notify to another waiter.
5076
5077 while (_Event < 0) {
5078 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5079 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5080 pthread_cond_destroy (_cond);
5081 pthread_cond_init (_cond, NULL) ;
5082 }
5083 assert_status(status == 0 || status == EINTR ||
5084 status == ETIME || status == ETIMEDOUT,
5085 status, "cond_timedwait");
5086 if (!FilterSpuriousWakeups) break ; // previous semantics
5087 if (status == ETIME || status == ETIMEDOUT) break ;
5088 // We consume and ignore EINTR and spurious wakeups.
5089 }
5090 --_nParked ;
5091 if (_Event >= 0) {
5092 ret = OS_OK;
5093 }
5094 _Event = 0 ;
5095 status = pthread_mutex_unlock(_mutex);
5096 assert_status(status == 0, status, "mutex_unlock");
5097 assert (_nParked == 0, "invariant") ;
5098 return ret;
5099 }
5100
5101 void os::PlatformEvent::unpark() {
5102 int v, AnyWaiters ;
5103 for (;;) {
5104 v = _Event ;
5105 if (v > 0) {
5106 // The LD of _Event could have reordered or be satisfied
5107 // by a read-aside from this processor's write buffer.
5108 // To avoid problems execute a barrier and then
5109 // ratify the value.
5110 OrderAccess::fence() ;
5111 if (_Event == v) return ;
5112 continue ;
5113 }
5114 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5115 }
5116 if (v < 0) {
5117 // Wait for the thread associated with the event to vacate
5118 int status = pthread_mutex_lock(_mutex);
5119 assert_status(status == 0, status, "mutex_lock");
5120 AnyWaiters = _nParked ;
5121 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5122 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5123 AnyWaiters = 0 ;
5124 pthread_cond_signal (_cond);
5125 }
5126 status = pthread_mutex_unlock(_mutex);
5127 assert_status(status == 0, status, "mutex_unlock");
5128 if (AnyWaiters != 0) {
5129 status = pthread_cond_signal(_cond);
5130 assert_status(status == 0, status, "cond_signal");
5131 }
5132 }
5133
5134 // Note that we signal() _after dropping the lock for "immortal" Events.
5135 // This is safe and avoids a common class of futile wakeups. In rare
5136 // circumstances this can cause a thread to return prematurely from
5137 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5138 // simply re-test the condition and re-park itself.
5139 }
5140
5141
5142 // JSR166
5143 // -------------------------------------------------------
5144
5145 /*
5146 * The solaris and linux implementations of park/unpark are fairly
5147 * conservative for now, but can be improved. They currently use a
5148 * mutex/condvar pair, plus a a count.
5149 * Park decrements count if > 0, else does a condvar wait. Unpark
5150 * sets count to 1 and signals condvar. Only one thread ever waits
5151 * on the condvar. Contention seen when trying to park implies that someone
5152 * is unparking you, so don't wait. And spurious returns are fine, so there
5153 * is no need to track notifications.
5154 */
5155
5156
5157 #define NANOSECS_PER_SEC 1000000000
5158 #define NANOSECS_PER_MILLISEC 1000000
5159 #define MAX_SECS 100000000
5160 /*
5161 * This code is common to linux and solaris and will be moved to a
5162 * common place in dolphin.
5163 *
5164 * The passed in time value is either a relative time in nanoseconds
5165 * or an absolute time in milliseconds. Either way it has to be unpacked
5166 * into suitable seconds and nanoseconds components and stored in the
5167 * given timespec structure.
5168 * Given time is a 64-bit value and the time_t used in the timespec is only
5169 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5170 * overflow if times way in the future are given. Further on Solaris versions
5171 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5172 * number of seconds, in abstime, is less than current_time + 100,000,000.
5173 * As it will be 28 years before "now + 100000000" will overflow we can
5174 * ignore overflow and just impose a hard-limit on seconds using the value
5175 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5176 * years from "now".
5177 */
5178
5179 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5180 assert (time > 0, "convertTime");
5181
5182 struct timeval now;
5183 int status = gettimeofday(&now, NULL);
5184 assert(status == 0, "gettimeofday");
5185
5186 time_t max_secs = now.tv_sec + MAX_SECS;
5187
5188 if (isAbsolute) {
5189 jlong secs = time / 1000;
5190 if (secs > max_secs) {
5191 absTime->tv_sec = max_secs;
5192 }
5193 else {
5194 absTime->tv_sec = secs;
5195 }
5196 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5197 }
5198 else {
5199 jlong secs = time / NANOSECS_PER_SEC;
5200 if (secs >= MAX_SECS) {
5201 absTime->tv_sec = max_secs;
5202 absTime->tv_nsec = 0;
5203 }
5204 else {
5205 absTime->tv_sec = now.tv_sec + secs;
5206 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5207 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5208 absTime->tv_nsec -= NANOSECS_PER_SEC;
5209 ++absTime->tv_sec; // note: this must be <= max_secs
5210 }
5211 }
5212 }
5213 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5214 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5215 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5216 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5217 }
5218
5219 void Parker::park(bool isAbsolute, jlong time) {
5220 // Optional fast-path check:
5221 // Return immediately if a permit is available.
5222 if (_counter > 0) {
5223 _counter = 0 ;
5224 OrderAccess::fence();
5225 return ;
5226 }
5227
5228 Thread* thread = Thread::current();
5229 assert(thread->is_Java_thread(), "Must be JavaThread");
5230 JavaThread *jt = (JavaThread *)thread;
5231
5232 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5233 // Check interrupt before trying to wait
5234 if (Thread::is_interrupted(thread, false)) {
5235 return;
5236 }
5237
5238 // Next, demultiplex/decode time arguments
5239 timespec absTime;
5240 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5241 return;
5242 }
5243 if (time > 0) {
5244 unpackTime(&absTime, isAbsolute, time);
5245 }
5246
5247
5248 // Enter safepoint region
5249 // Beware of deadlocks such as 6317397.
5250 // The per-thread Parker:: mutex is a classic leaf-lock.
5251 // In particular a thread must never block on the Threads_lock while
5252 // holding the Parker:: mutex. If safepoints are pending both the
5253 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5254 ThreadBlockInVM tbivm(jt);
5255
5256 // Don't wait if cannot get lock since interference arises from
5257 // unblocking. Also. check interrupt before trying wait
5258 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5259 return;
5260 }
5261
5262 int status ;
5263 if (_counter > 0) { // no wait needed
5264 _counter = 0;
5265 status = pthread_mutex_unlock(_mutex);
5266 assert (status == 0, "invariant") ;
5267 OrderAccess::fence();
5268 return;
5269 }
5270
5271 #ifdef ASSERT
5272 // Don't catch signals while blocked; let the running threads have the signals.
5273 // (This allows a debugger to break into the running thread.)
5274 sigset_t oldsigs;
5275 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5276 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5277 #endif
5278
5279 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5280 jt->set_suspend_equivalent();
5281 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5282
5283 if (time == 0) {
5284 status = pthread_cond_wait (_cond, _mutex) ;
5285 } else {
5286 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5287 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5288 pthread_cond_destroy (_cond) ;
5289 pthread_cond_init (_cond, NULL);
5290 }
5291 }
5292 assert_status(status == 0 || status == EINTR ||
5293 status == ETIME || status == ETIMEDOUT,
5294 status, "cond_timedwait");
5295
5296 #ifdef ASSERT
5297 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5298 #endif
5299
5300 _counter = 0 ;
5301 status = pthread_mutex_unlock(_mutex) ;
5302 assert_status(status == 0, status, "invariant") ;
5303 // If externally suspended while waiting, re-suspend
5304 if (jt->handle_special_suspend_equivalent_condition()) {
5305 jt->java_suspend_self();
5306 }
5307
5308 OrderAccess::fence();
5309 }
5310
5311 void Parker::unpark() {
5312 int s, status ;
5313 status = pthread_mutex_lock(_mutex);
5314 assert (status == 0, "invariant") ;
5315 s = _counter;
5316 _counter = 1;
5317 if (s < 1) {
5318 if (WorkAroundNPTLTimedWaitHang) {
5319 status = pthread_cond_signal (_cond) ;
5320 assert (status == 0, "invariant") ;
5321 status = pthread_mutex_unlock(_mutex);
5322 assert (status == 0, "invariant") ;
5323 } else {
5324 status = pthread_mutex_unlock(_mutex);
5325 assert (status == 0, "invariant") ;
5326 status = pthread_cond_signal (_cond) ;
5327 assert (status == 0, "invariant") ;
5328 }
5329 } else {
5330 pthread_mutex_unlock(_mutex);
5331 assert (status == 0, "invariant") ;
5332 }
5333 }
5334
5335
5336 extern char** environ;
5337
5338 #ifndef __NR_fork
5339 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5340 #endif
5341
5342 #ifndef __NR_execve
5343 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5344 #endif
5345
5346 // Run the specified command in a separate process. Return its exit value,
5347 // or -1 on failure (e.g. can't fork a new process).
5348 // Unlike system(), this function can be called from signal handler. It
5349 // doesn't block SIGINT et al.
5350 int os::fork_and_exec(char* cmd) {
5351 const char * argv[4] = {"sh", "-c", cmd, NULL};
5352
5353 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5354 // pthread_atfork handlers and reset pthread library. All we need is a
5355 // separate process to execve. Make a direct syscall to fork process.
5356 // On IA64 there's no fork syscall, we have to use fork() and hope for
5357 // the best...
5358 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5359 IA64_ONLY(fork();)
5360
5361 if (pid < 0) {
5362 // fork failed
5363 return -1;
5364
5365 } else if (pid == 0) {
5366 // child process
5367
5368 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5369 // first to kill every thread on the thread list. Because this list is
5370 // not reset by fork() (see notes above), execve() will instead kill
5371 // every thread in the parent process. We know this is the only thread
5372 // in the new process, so make a system call directly.
5373 // IA64 should use normal execve() from glibc to match the glibc fork()
5374 // above.
5375 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5376 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5377
5378 // execve failed
5379 _exit(-1);
5380
5381 } else {
5382 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5383 // care about the actual exit code, for now.
5384
5385 int status;
5386
5387 // Wait for the child process to exit. This returns immediately if
5388 // the child has already exited. */
5389 while (waitpid(pid, &status, 0) < 0) {
5390 switch (errno) {
5391 case ECHILD: return 0;
5392 case EINTR: break;
5393 default: return -1;
5394 }
5395 }
5396
5397 if (WIFEXITED(status)) {
5398 // The child exited normally; get its exit code.
5399 return WEXITSTATUS(status);
5400 } else if (WIFSIGNALED(status)) {
5401 // The child exited because of a signal
5402 // The best value to return is 0x80 + signal number,
5403 // because that is what all Unix shells do, and because
5404 // it allows callers to distinguish between process exit and
5405 // process death by signal.
5406 return 0x80 + WTERMSIG(status);
5407 } else {
5408 // Unknown exit code; pass it through
5409 return status;
5410 }
5411 }
5412 }
5413
5414 // is_headless_jre()
5415 //
5416 // Test for the existence of libmawt in motif21 or xawt directories
5417 // in order to report if we are running in a headless jre
5418 //
5419 bool os::is_headless_jre() {
5420 struct stat statbuf;
5421 char buf[MAXPATHLEN];
5422 char libmawtpath[MAXPATHLEN];
5423 const char *xawtstr = "/xawt/libmawt.so";
5424 const char *motifstr = "/motif21/libmawt.so";
5425 char *p;
5426
5427 // Get path to libjvm.so
5428 os::jvm_path(buf, sizeof(buf));
5429
5430 // Get rid of libjvm.so
5431 p = strrchr(buf, '/');
5432 if (p == NULL) return false;
5433 else *p = '\0';
5434
5435 // Get rid of client or server
5436 p = strrchr(buf, '/');
5437 if (p == NULL) return false;
5438 else *p = '\0';
5439
5440 // check xawt/libmawt.so
5441 strcpy(libmawtpath, buf);
5442 strcat(libmawtpath, xawtstr);
5443 if (::stat(libmawtpath, &statbuf) == 0) return false;
5444
5445 // check motif21/libmawt.so
5446 strcpy(libmawtpath, buf);
5447 strcat(libmawtpath, motifstr);
5448 if (::stat(libmawtpath, &statbuf) == 0) return false;
5449
5450 return true;
5451 }
5452
5453
5454 #ifdef JAVASE_EMBEDDED
5455 //
5456 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5457 //
5458 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5459
5460 // ctor
5461 //
5462 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5463 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5464 _fd = fd;
5465
5466 if (os::create_thread(this, os::os_thread)) {
5467 _memnotify_thread = this;
5468 os::set_priority(this, NearMaxPriority);
5469 os::start_thread(this);
5470 }
5471 }
5472
5473 // Where all the work gets done
5474 //
5475 void MemNotifyThread::run() {
5476 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5477
5478 // Set up the select arguments
5479 fd_set rfds;
5480 if (_fd != -1) {
5481 FD_ZERO(&rfds);
5482 FD_SET(_fd, &rfds);
5483 }
5484
5485 // Now wait for the mem_notify device to wake up
5486 while (1) {
5487 // Wait for the mem_notify device to signal us..
5488 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5489 if (rc == -1) {
5490 perror("select!\n");
5491 break;
5492 } else if (rc) {
5493 //ssize_t free_before = os::available_memory();
5494 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5495
5496 // The kernel is telling us there is not much memory left...
5497 // try to do something about that
5498
5499 // If we are not already in a GC, try one.
5500 if (!Universe::heap()->is_gc_active()) {
5501 Universe::heap()->collect(GCCause::_allocation_failure);
5502
5503 //ssize_t free_after = os::available_memory();
5504 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5505 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5506 }
5507 // We might want to do something like the following if we find the GC's are not helping...
5508 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5509 }
5510 }
5511 }
5512
5513 //
5514 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5515 //
5516 void MemNotifyThread::start() {
5517 int fd;
5518 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5519 if (fd < 0) {
5520 return;
5521 }
5522
5523 if (memnotify_thread() == NULL) {
5524 new MemNotifyThread(fd);
5525 }
5526 }
5527 #endif // JAVASE_EMBEDDED