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--- old/src/os/linux/vm/os_linux.cpp
+++ new/src/os/linux/vm/os_linux.cpp
1 1 /*
2 2 * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 // no precompiled headers
26 26 #include "classfile/classLoader.hpp"
27 27 #include "classfile/systemDictionary.hpp"
28 28 #include "classfile/vmSymbols.hpp"
29 29 #include "code/icBuffer.hpp"
30 30 #include "code/vtableStubs.hpp"
31 31 #include "compiler/compileBroker.hpp"
32 32 #include "interpreter/interpreter.hpp"
33 33 #include "jvm_linux.h"
34 34 #include "memory/allocation.inline.hpp"
35 35 #include "memory/filemap.hpp"
36 36 #include "mutex_linux.inline.hpp"
37 37 #include "oops/oop.inline.hpp"
38 38 #include "os_share_linux.hpp"
39 39 #include "prims/jniFastGetField.hpp"
40 40 #include "prims/jvm.h"
41 41 #include "prims/jvm_misc.hpp"
42 42 #include "runtime/arguments.hpp"
43 43 #include "runtime/extendedPC.hpp"
44 44 #include "runtime/globals.hpp"
45 45 #include "runtime/interfaceSupport.hpp"
46 46 #include "runtime/java.hpp"
47 47 #include "runtime/javaCalls.hpp"
48 48 #include "runtime/mutexLocker.hpp"
49 49 #include "runtime/objectMonitor.hpp"
50 50 #include "runtime/osThread.hpp"
51 51 #include "runtime/perfMemory.hpp"
52 52 #include "runtime/sharedRuntime.hpp"
53 53 #include "runtime/statSampler.hpp"
54 54 #include "runtime/stubRoutines.hpp"
55 55 #include "runtime/threadCritical.hpp"
56 56 #include "runtime/timer.hpp"
57 57 #include "services/attachListener.hpp"
58 58 #include "services/runtimeService.hpp"
59 59 #include "thread_linux.inline.hpp"
60 60 #include "utilities/decoder.hpp"
61 61 #include "utilities/defaultStream.hpp"
62 62 #include "utilities/events.hpp"
63 63 #include "utilities/growableArray.hpp"
64 64 #include "utilities/vmError.hpp"
65 65 #ifdef TARGET_ARCH_x86
66 66 # include "assembler_x86.inline.hpp"
67 67 # include "nativeInst_x86.hpp"
68 68 #endif
69 69 #ifdef TARGET_ARCH_sparc
70 70 # include "assembler_sparc.inline.hpp"
71 71 # include "nativeInst_sparc.hpp"
72 72 #endif
73 73 #ifdef TARGET_ARCH_zero
74 74 # include "assembler_zero.inline.hpp"
75 75 # include "nativeInst_zero.hpp"
76 76 #endif
77 77 #ifdef TARGET_ARCH_arm
78 78 # include "assembler_arm.inline.hpp"
79 79 # include "nativeInst_arm.hpp"
80 80 #endif
81 81 #ifdef TARGET_ARCH_ppc
82 82 # include "assembler_ppc.inline.hpp"
83 83 # include "nativeInst_ppc.hpp"
84 84 #endif
85 85 #ifdef COMPILER1
86 86 #include "c1/c1_Runtime1.hpp"
87 87 #endif
88 88 #ifdef COMPILER2
89 89 #include "opto/runtime.hpp"
90 90 #endif
91 91
92 92 // put OS-includes here
93 93 # include <sys/types.h>
94 94 # include <sys/mman.h>
95 95 # include <sys/stat.h>
96 96 # include <sys/select.h>
97 97 # include <pthread.h>
98 98 # include <signal.h>
99 99 # include <errno.h>
100 100 # include <dlfcn.h>
101 101 # include <stdio.h>
102 102 # include <unistd.h>
103 103 # include <sys/resource.h>
104 104 # include <pthread.h>
105 105 # include <sys/stat.h>
106 106 # include <sys/time.h>
107 107 # include <sys/times.h>
108 108 # include <sys/utsname.h>
109 109 # include <sys/socket.h>
110 110 # include <sys/wait.h>
111 111 # include <pwd.h>
112 112 # include <poll.h>
113 113 # include <semaphore.h>
114 114 # include <fcntl.h>
115 115 # include <string.h>
116 116 # include <syscall.h>
117 117 # include <sys/sysinfo.h>
118 118 # include <gnu/libc-version.h>
119 119 # include <sys/ipc.h>
120 120 # include <sys/shm.h>
121 121 # include <link.h>
122 122 # include <stdint.h>
123 123 # include <inttypes.h>
124 124 # include <sys/ioctl.h>
125 125
126 126 #define MAX_PATH (2 * K)
127 127
128 128 // for timer info max values which include all bits
129 129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
130 130
131 131 #define LARGEPAGES_BIT (1 << 6)
132 132 ////////////////////////////////////////////////////////////////////////////////
133 133 // global variables
134 134 julong os::Linux::_physical_memory = 0;
135 135
136 136 address os::Linux::_initial_thread_stack_bottom = NULL;
137 137 uintptr_t os::Linux::_initial_thread_stack_size = 0;
138 138
139 139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
140 140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
141 141 Mutex* os::Linux::_createThread_lock = NULL;
142 142 pthread_t os::Linux::_main_thread;
143 143 int os::Linux::_page_size = -1;
144 144 bool os::Linux::_is_floating_stack = false;
145 145 bool os::Linux::_is_NPTL = false;
146 146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 147 const char * os::Linux::_glibc_version = NULL;
148 148 const char * os::Linux::_libpthread_version = NULL;
149 149
150 150 static jlong initial_time_count=0;
151 151
152 152 static int clock_tics_per_sec = 100;
153 153
154 154 // For diagnostics to print a message once. see run_periodic_checks
155 155 static sigset_t check_signal_done;
156 156 static bool check_signals = true;;
157 157
158 158 static pid_t _initial_pid = 0;
159 159
160 160 /* Signal number used to suspend/resume a thread */
161 161
162 162 /* do not use any signal number less than SIGSEGV, see 4355769 */
163 163 static int SR_signum = SIGUSR2;
164 164 sigset_t SR_sigset;
165 165
166 166 /* Used to protect dlsym() calls */
167 167 static pthread_mutex_t dl_mutex;
168 168
169 169 #ifdef JAVASE_EMBEDDED
170 170 class MemNotifyThread: public Thread {
171 171 friend class VMStructs;
172 172 public:
173 173 virtual void run();
174 174
175 175 private:
176 176 static MemNotifyThread* _memnotify_thread;
177 177 int _fd;
178 178
179 179 public:
180 180
181 181 // Constructor
182 182 MemNotifyThread(int fd);
183 183
184 184 // Tester
185 185 bool is_memnotify_thread() const { return true; }
186 186
187 187 // Printing
188 188 char* name() const { return (char*)"Linux MemNotify Thread"; }
189 189
190 190 // Returns the single instance of the MemNotifyThread
191 191 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
192 192
193 193 // Create and start the single instance of MemNotifyThread
194 194 static void start();
195 195 };
196 196 #endif // JAVASE_EMBEDDED
197 197
198 198 // utility functions
199 199
200 200 static int SR_initialize();
201 201 static int SR_finalize();
202 202
203 203 julong os::available_memory() {
204 204 return Linux::available_memory();
205 205 }
206 206
207 207 julong os::Linux::available_memory() {
208 208 // values in struct sysinfo are "unsigned long"
209 209 struct sysinfo si;
210 210 sysinfo(&si);
211 211
212 212 return (julong)si.freeram * si.mem_unit;
213 213 }
214 214
215 215 julong os::physical_memory() {
216 216 return Linux::physical_memory();
217 217 }
218 218
219 219 julong os::allocatable_physical_memory(julong size) {
220 220 #ifdef _LP64
221 221 return size;
222 222 #else
223 223 julong result = MIN2(size, (julong)3800*M);
224 224 if (!is_allocatable(result)) {
225 225 // See comments under solaris for alignment considerations
226 226 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
227 227 result = MIN2(size, reasonable_size);
228 228 }
229 229 return result;
230 230 #endif // _LP64
231 231 }
232 232
233 233 ////////////////////////////////////////////////////////////////////////////////
234 234 // environment support
235 235
236 236 bool os::getenv(const char* name, char* buf, int len) {
237 237 const char* val = ::getenv(name);
238 238 if (val != NULL && strlen(val) < (size_t)len) {
239 239 strcpy(buf, val);
240 240 return true;
241 241 }
242 242 if (len > 0) buf[0] = 0; // return a null string
243 243 return false;
244 244 }
245 245
246 246
247 247 // Return true if user is running as root.
248 248
249 249 bool os::have_special_privileges() {
250 250 static bool init = false;
251 251 static bool privileges = false;
252 252 if (!init) {
253 253 privileges = (getuid() != geteuid()) || (getgid() != getegid());
254 254 init = true;
255 255 }
256 256 return privileges;
257 257 }
258 258
259 259
260 260 #ifndef SYS_gettid
261 261 // i386: 224, ia64: 1105, amd64: 186, sparc 143
262 262 #ifdef __ia64__
263 263 #define SYS_gettid 1105
264 264 #elif __i386__
265 265 #define SYS_gettid 224
266 266 #elif __amd64__
267 267 #define SYS_gettid 186
268 268 #elif __sparc__
269 269 #define SYS_gettid 143
270 270 #else
271 271 #error define gettid for the arch
272 272 #endif
273 273 #endif
274 274
275 275 // Cpu architecture string
276 276 #if defined(ZERO)
277 277 static char cpu_arch[] = ZERO_LIBARCH;
278 278 #elif defined(IA64)
279 279 static char cpu_arch[] = "ia64";
280 280 #elif defined(IA32)
281 281 static char cpu_arch[] = "i386";
282 282 #elif defined(AMD64)
283 283 static char cpu_arch[] = "amd64";
284 284 #elif defined(ARM)
285 285 static char cpu_arch[] = "arm";
286 286 #elif defined(PPC)
287 287 static char cpu_arch[] = "ppc";
288 288 #elif defined(SPARC)
289 289 # ifdef _LP64
290 290 static char cpu_arch[] = "sparcv9";
291 291 # else
292 292 static char cpu_arch[] = "sparc";
293 293 # endif
294 294 #else
295 295 #error Add appropriate cpu_arch setting
296 296 #endif
297 297
298 298
299 299 // pid_t gettid()
300 300 //
301 301 // Returns the kernel thread id of the currently running thread. Kernel
302 302 // thread id is used to access /proc.
303 303 //
304 304 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
305 305 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
306 306 //
307 307 pid_t os::Linux::gettid() {
308 308 int rslt = syscall(SYS_gettid);
309 309 if (rslt == -1) {
310 310 // old kernel, no NPTL support
311 311 return getpid();
312 312 } else {
313 313 return (pid_t)rslt;
314 314 }
315 315 }
316 316
317 317 // Most versions of linux have a bug where the number of processors are
318 318 // determined by looking at the /proc file system. In a chroot environment,
319 319 // the system call returns 1. This causes the VM to act as if it is
320 320 // a single processor and elide locking (see is_MP() call).
321 321 static bool unsafe_chroot_detected = false;
322 322 static const char *unstable_chroot_error = "/proc file system not found.\n"
323 323 "Java may be unstable running multithreaded in a chroot "
324 324 "environment on Linux when /proc filesystem is not mounted.";
325 325
326 326 void os::Linux::initialize_system_info() {
327 327 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
328 328 if (processor_count() == 1) {
329 329 pid_t pid = os::Linux::gettid();
330 330 char fname[32];
331 331 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
332 332 FILE *fp = fopen(fname, "r");
333 333 if (fp == NULL) {
334 334 unsafe_chroot_detected = true;
335 335 } else {
336 336 fclose(fp);
337 337 }
338 338 }
339 339 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
340 340 assert(processor_count() > 0, "linux error");
341 341 }
342 342
343 343 void os::init_system_properties_values() {
344 344 // char arch[12];
345 345 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
346 346
347 347 // The next steps are taken in the product version:
348 348 //
349 349 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
350 350 // This library should be located at:
351 351 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
352 352 //
353 353 // If "/jre/lib/" appears at the right place in the path, then we
354 354 // assume libjvm[_g].so is installed in a JDK and we use this path.
355 355 //
356 356 // Otherwise exit with message: "Could not create the Java virtual machine."
357 357 //
358 358 // The following extra steps are taken in the debugging version:
359 359 //
360 360 // If "/jre/lib/" does NOT appear at the right place in the path
361 361 // instead of exit check for $JAVA_HOME environment variable.
362 362 //
363 363 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
364 364 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
365 365 // it looks like libjvm[_g].so is installed there
366 366 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
367 367 //
368 368 // Otherwise exit.
369 369 //
370 370 // Important note: if the location of libjvm.so changes this
371 371 // code needs to be changed accordingly.
372 372
373 373 // The next few definitions allow the code to be verbatim:
374 374 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
375 375 #define getenv(n) ::getenv(n)
376 376
377 377 /*
378 378 * See ld(1):
379 379 * The linker uses the following search paths to locate required
380 380 * shared libraries:
381 381 * 1: ...
382 382 * ...
383 383 * 7: The default directories, normally /lib and /usr/lib.
384 384 */
385 385 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
386 386 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
387 387 #else
388 388 #define DEFAULT_LIBPATH "/lib:/usr/lib"
389 389 #endif
390 390
391 391 #define EXTENSIONS_DIR "/lib/ext"
392 392 #define ENDORSED_DIR "/lib/endorsed"
393 393 #define REG_DIR "/usr/java/packages"
394 394
395 395 {
396 396 /* sysclasspath, java_home, dll_dir */
397 397 {
398 398 char *home_path;
399 399 char *dll_path;
400 400 char *pslash;
401 401 char buf[MAXPATHLEN];
402 402 os::jvm_path(buf, sizeof(buf));
403 403
404 404 // Found the full path to libjvm.so.
405 405 // Now cut the path to <java_home>/jre if we can.
406 406 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
407 407 pslash = strrchr(buf, '/');
408 408 if (pslash != NULL)
409 409 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
410 410 dll_path = malloc(strlen(buf) + 1);
411 411 if (dll_path == NULL)
412 412 return;
413 413 strcpy(dll_path, buf);
414 414 Arguments::set_dll_dir(dll_path);
415 415
416 416 if (pslash != NULL) {
417 417 pslash = strrchr(buf, '/');
418 418 if (pslash != NULL) {
419 419 *pslash = '\0'; /* get rid of /<arch> */
420 420 pslash = strrchr(buf, '/');
421 421 if (pslash != NULL)
422 422 *pslash = '\0'; /* get rid of /lib */
423 423 }
424 424 }
425 425
426 426 home_path = malloc(strlen(buf) + 1);
427 427 if (home_path == NULL)
428 428 return;
429 429 strcpy(home_path, buf);
430 430 Arguments::set_java_home(home_path);
431 431
432 432 if (!set_boot_path('/', ':'))
433 433 return;
434 434 }
435 435
436 436 /*
437 437 * Where to look for native libraries
438 438 *
439 439 * Note: Due to a legacy implementation, most of the library path
440 440 * is set in the launcher. This was to accomodate linking restrictions
441 441 * on legacy Linux implementations (which are no longer supported).
442 442 * Eventually, all the library path setting will be done here.
443 443 *
444 444 * However, to prevent the proliferation of improperly built native
445 445 * libraries, the new path component /usr/java/packages is added here.
446 446 * Eventually, all the library path setting will be done here.
447 447 */
448 448 {
449 449 char *ld_library_path;
450 450
451 451 /*
452 452 * Construct the invariant part of ld_library_path. Note that the
453 453 * space for the colon and the trailing null are provided by the
454 454 * nulls included by the sizeof operator (so actually we allocate
455 455 * a byte more than necessary).
456 456 */
457 457 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
458 458 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
459 459 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
460 460
461 461 /*
462 462 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
463 463 * should always exist (until the legacy problem cited above is
464 464 * addressed).
465 465 */
466 466 char *v = getenv("LD_LIBRARY_PATH");
467 467 if (v != NULL) {
468 468 char *t = ld_library_path;
469 469 /* That's +1 for the colon and +1 for the trailing '\0' */
470 470 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
471 471 sprintf(ld_library_path, "%s:%s", v, t);
472 472 }
473 473 Arguments::set_library_path(ld_library_path);
474 474 }
475 475
476 476 /*
477 477 * Extensions directories.
478 478 *
479 479 * Note that the space for the colon and the trailing null are provided
480 480 * by the nulls included by the sizeof operator (so actually one byte more
481 481 * than necessary is allocated).
482 482 */
483 483 {
484 484 char *buf = malloc(strlen(Arguments::get_java_home()) +
485 485 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
486 486 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
487 487 Arguments::get_java_home());
488 488 Arguments::set_ext_dirs(buf);
489 489 }
490 490
491 491 /* Endorsed standards default directory. */
492 492 {
493 493 char * buf;
494 494 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
495 495 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
496 496 Arguments::set_endorsed_dirs(buf);
497 497 }
498 498 }
499 499
500 500 #undef malloc
501 501 #undef getenv
502 502 #undef EXTENSIONS_DIR
503 503 #undef ENDORSED_DIR
504 504
505 505 // Done
506 506 return;
507 507 }
508 508
509 509 ////////////////////////////////////////////////////////////////////////////////
510 510 // breakpoint support
511 511
512 512 void os::breakpoint() {
513 513 BREAKPOINT;
514 514 }
515 515
516 516 extern "C" void breakpoint() {
517 517 // use debugger to set breakpoint here
518 518 }
519 519
520 520 ////////////////////////////////////////////////////////////////////////////////
521 521 // signal support
522 522
523 523 debug_only(static bool signal_sets_initialized = false);
524 524 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
525 525
526 526 bool os::Linux::is_sig_ignored(int sig) {
527 527 struct sigaction oact;
528 528 sigaction(sig, (struct sigaction*)NULL, &oact);
529 529 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
530 530 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
531 531 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
532 532 return true;
533 533 else
534 534 return false;
535 535 }
536 536
537 537 void os::Linux::signal_sets_init() {
538 538 // Should also have an assertion stating we are still single-threaded.
539 539 assert(!signal_sets_initialized, "Already initialized");
540 540 // Fill in signals that are necessarily unblocked for all threads in
541 541 // the VM. Currently, we unblock the following signals:
542 542 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
543 543 // by -Xrs (=ReduceSignalUsage));
544 544 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
545 545 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
546 546 // the dispositions or masks wrt these signals.
547 547 // Programs embedding the VM that want to use the above signals for their
548 548 // own purposes must, at this time, use the "-Xrs" option to prevent
549 549 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
550 550 // (See bug 4345157, and other related bugs).
551 551 // In reality, though, unblocking these signals is really a nop, since
552 552 // these signals are not blocked by default.
553 553 sigemptyset(&unblocked_sigs);
554 554 sigemptyset(&allowdebug_blocked_sigs);
555 555 sigaddset(&unblocked_sigs, SIGILL);
556 556 sigaddset(&unblocked_sigs, SIGSEGV);
557 557 sigaddset(&unblocked_sigs, SIGBUS);
558 558 sigaddset(&unblocked_sigs, SIGFPE);
559 559 sigaddset(&unblocked_sigs, SR_signum);
560 560
561 561 if (!ReduceSignalUsage) {
562 562 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
563 563 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
564 564 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
565 565 }
566 566 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
567 567 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
568 568 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
569 569 }
570 570 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
571 571 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
572 572 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
573 573 }
574 574 }
575 575 // Fill in signals that are blocked by all but the VM thread.
576 576 sigemptyset(&vm_sigs);
577 577 if (!ReduceSignalUsage)
578 578 sigaddset(&vm_sigs, BREAK_SIGNAL);
579 579 debug_only(signal_sets_initialized = true);
580 580
581 581 }
582 582
583 583 // These are signals that are unblocked while a thread is running Java.
584 584 // (For some reason, they get blocked by default.)
585 585 sigset_t* os::Linux::unblocked_signals() {
586 586 assert(signal_sets_initialized, "Not initialized");
587 587 return &unblocked_sigs;
588 588 }
589 589
590 590 // These are the signals that are blocked while a (non-VM) thread is
591 591 // running Java. Only the VM thread handles these signals.
592 592 sigset_t* os::Linux::vm_signals() {
593 593 assert(signal_sets_initialized, "Not initialized");
594 594 return &vm_sigs;
595 595 }
596 596
597 597 // These are signals that are blocked during cond_wait to allow debugger in
598 598 sigset_t* os::Linux::allowdebug_blocked_signals() {
599 599 assert(signal_sets_initialized, "Not initialized");
600 600 return &allowdebug_blocked_sigs;
601 601 }
602 602
603 603 void os::Linux::hotspot_sigmask(Thread* thread) {
604 604
605 605 //Save caller's signal mask before setting VM signal mask
606 606 sigset_t caller_sigmask;
607 607 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
608 608
609 609 OSThread* osthread = thread->osthread();
610 610 osthread->set_caller_sigmask(caller_sigmask);
611 611
612 612 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
613 613
614 614 if (!ReduceSignalUsage) {
615 615 if (thread->is_VM_thread()) {
616 616 // Only the VM thread handles BREAK_SIGNAL ...
617 617 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
618 618 } else {
619 619 // ... all other threads block BREAK_SIGNAL
620 620 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
621 621 }
622 622 }
623 623 }
624 624
625 625 //////////////////////////////////////////////////////////////////////////////
626 626 // detecting pthread library
627 627
628 628 void os::Linux::libpthread_init() {
629 629 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
630 630 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
631 631 // generic name for earlier versions.
632 632 // Define macros here so we can build HotSpot on old systems.
633 633 # ifndef _CS_GNU_LIBC_VERSION
634 634 # define _CS_GNU_LIBC_VERSION 2
635 635 # endif
636 636 # ifndef _CS_GNU_LIBPTHREAD_VERSION
637 637 # define _CS_GNU_LIBPTHREAD_VERSION 3
638 638 # endif
639 639
640 640 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
641 641 if (n > 0) {
642 642 char *str = (char *)malloc(n);
643 643 confstr(_CS_GNU_LIBC_VERSION, str, n);
644 644 os::Linux::set_glibc_version(str);
645 645 } else {
646 646 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
647 647 static char _gnu_libc_version[32];
648 648 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
649 649 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
650 650 os::Linux::set_glibc_version(_gnu_libc_version);
651 651 }
652 652
653 653 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
654 654 if (n > 0) {
655 655 char *str = (char *)malloc(n);
656 656 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
657 657 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
658 658 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
659 659 // is the case. LinuxThreads has a hard limit on max number of threads.
660 660 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
661 661 // On the other hand, NPTL does not have such a limit, sysconf()
662 662 // will return -1 and errno is not changed. Check if it is really NPTL.
663 663 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
664 664 strstr(str, "NPTL") &&
665 665 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
666 666 free(str);
667 667 os::Linux::set_libpthread_version("linuxthreads");
668 668 } else {
669 669 os::Linux::set_libpthread_version(str);
670 670 }
671 671 } else {
672 672 // glibc before 2.3.2 only has LinuxThreads.
673 673 os::Linux::set_libpthread_version("linuxthreads");
674 674 }
675 675
676 676 if (strstr(libpthread_version(), "NPTL")) {
677 677 os::Linux::set_is_NPTL();
678 678 } else {
679 679 os::Linux::set_is_LinuxThreads();
680 680 }
681 681
682 682 // LinuxThreads have two flavors: floating-stack mode, which allows variable
683 683 // stack size; and fixed-stack mode. NPTL is always floating-stack.
684 684 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
685 685 os::Linux::set_is_floating_stack();
686 686 }
687 687 }
688 688
689 689 /////////////////////////////////////////////////////////////////////////////
690 690 // thread stack
691 691
692 692 // Force Linux kernel to expand current thread stack. If "bottom" is close
693 693 // to the stack guard, caller should block all signals.
694 694 //
695 695 // MAP_GROWSDOWN:
696 696 // A special mmap() flag that is used to implement thread stacks. It tells
697 697 // kernel that the memory region should extend downwards when needed. This
698 698 // allows early versions of LinuxThreads to only mmap the first few pages
699 699 // when creating a new thread. Linux kernel will automatically expand thread
700 700 // stack as needed (on page faults).
701 701 //
702 702 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
703 703 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
704 704 // region, it's hard to tell if the fault is due to a legitimate stack
705 705 // access or because of reading/writing non-exist memory (e.g. buffer
706 706 // overrun). As a rule, if the fault happens below current stack pointer,
707 707 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
708 708 // application (see Linux kernel fault.c).
709 709 //
710 710 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
711 711 // stack overflow detection.
712 712 //
713 713 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
714 714 // not use this flag. However, the stack of initial thread is not created
715 715 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
716 716 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
717 717 // and then attach the thread to JVM.
718 718 //
719 719 // To get around the problem and allow stack banging on Linux, we need to
720 720 // manually expand thread stack after receiving the SIGSEGV.
721 721 //
722 722 // There are two ways to expand thread stack to address "bottom", we used
723 723 // both of them in JVM before 1.5:
724 724 // 1. adjust stack pointer first so that it is below "bottom", and then
725 725 // touch "bottom"
726 726 // 2. mmap() the page in question
727 727 //
728 728 // Now alternate signal stack is gone, it's harder to use 2. For instance,
729 729 // if current sp is already near the lower end of page 101, and we need to
730 730 // call mmap() to map page 100, it is possible that part of the mmap() frame
731 731 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
732 732 // That will destroy the mmap() frame and cause VM to crash.
733 733 //
734 734 // The following code works by adjusting sp first, then accessing the "bottom"
735 735 // page to force a page fault. Linux kernel will then automatically expand the
736 736 // stack mapping.
737 737 //
738 738 // _expand_stack_to() assumes its frame size is less than page size, which
739 739 // should always be true if the function is not inlined.
740 740
741 741 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
742 742 #define NOINLINE
743 743 #else
744 744 #define NOINLINE __attribute__ ((noinline))
745 745 #endif
746 746
747 747 static void _expand_stack_to(address bottom) NOINLINE;
748 748
749 749 static void _expand_stack_to(address bottom) {
750 750 address sp;
751 751 size_t size;
752 752 volatile char *p;
753 753
754 754 // Adjust bottom to point to the largest address within the same page, it
755 755 // gives us a one-page buffer if alloca() allocates slightly more memory.
756 756 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
757 757 bottom += os::Linux::page_size() - 1;
758 758
759 759 // sp might be slightly above current stack pointer; if that's the case, we
760 760 // will alloca() a little more space than necessary, which is OK. Don't use
761 761 // os::current_stack_pointer(), as its result can be slightly below current
762 762 // stack pointer, causing us to not alloca enough to reach "bottom".
763 763 sp = (address)&sp;
764 764
765 765 if (sp > bottom) {
766 766 size = sp - bottom;
767 767 p = (volatile char *)alloca(size);
768 768 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
769 769 p[0] = '\0';
770 770 }
771 771 }
772 772
773 773 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
774 774 assert(t!=NULL, "just checking");
775 775 assert(t->osthread()->expanding_stack(), "expand should be set");
776 776 assert(t->stack_base() != NULL, "stack_base was not initialized");
777 777
778 778 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
779 779 sigset_t mask_all, old_sigset;
780 780 sigfillset(&mask_all);
781 781 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
782 782 _expand_stack_to(addr);
783 783 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
784 784 return true;
785 785 }
786 786 return false;
787 787 }
788 788
789 789 //////////////////////////////////////////////////////////////////////////////
790 790 // create new thread
791 791
792 792 static address highest_vm_reserved_address();
793 793
794 794 // check if it's safe to start a new thread
795 795 static bool _thread_safety_check(Thread* thread) {
796 796 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
797 797 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
798 798 // Heap is mmap'ed at lower end of memory space. Thread stacks are
799 799 // allocated (MAP_FIXED) from high address space. Every thread stack
800 800 // occupies a fixed size slot (usually 2Mbytes, but user can change
801 801 // it to other values if they rebuild LinuxThreads).
802 802 //
803 803 // Problem with MAP_FIXED is that mmap() can still succeed even part of
804 804 // the memory region has already been mmap'ed. That means if we have too
805 805 // many threads and/or very large heap, eventually thread stack will
806 806 // collide with heap.
807 807 //
808 808 // Here we try to prevent heap/stack collision by comparing current
809 809 // stack bottom with the highest address that has been mmap'ed by JVM
810 810 // plus a safety margin for memory maps created by native code.
811 811 //
812 812 // This feature can be disabled by setting ThreadSafetyMargin to 0
813 813 //
814 814 if (ThreadSafetyMargin > 0) {
815 815 address stack_bottom = os::current_stack_base() - os::current_stack_size();
816 816
817 817 // not safe if our stack extends below the safety margin
818 818 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
819 819 } else {
820 820 return true;
821 821 }
822 822 } else {
823 823 // Floating stack LinuxThreads or NPTL:
824 824 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
825 825 // there's not enough space left, pthread_create() will fail. If we come
826 826 // here, that means enough space has been reserved for stack.
827 827 return true;
828 828 }
829 829 }
830 830
831 831 // Thread start routine for all newly created threads
832 832 static void *java_start(Thread *thread) {
833 833 // Try to randomize the cache line index of hot stack frames.
834 834 // This helps when threads of the same stack traces evict each other's
835 835 // cache lines. The threads can be either from the same JVM instance, or
836 836 // from different JVM instances. The benefit is especially true for
837 837 // processors with hyperthreading technology.
838 838 static int counter = 0;
839 839 int pid = os::current_process_id();
840 840 alloca(((pid ^ counter++) & 7) * 128);
841 841
842 842 ThreadLocalStorage::set_thread(thread);
843 843
844 844 OSThread* osthread = thread->osthread();
845 845 Monitor* sync = osthread->startThread_lock();
846 846
847 847 // non floating stack LinuxThreads needs extra check, see above
848 848 if (!_thread_safety_check(thread)) {
849 849 // notify parent thread
850 850 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
851 851 osthread->set_state(ZOMBIE);
852 852 sync->notify_all();
853 853 return NULL;
854 854 }
855 855
856 856 // thread_id is kernel thread id (similar to Solaris LWP id)
857 857 osthread->set_thread_id(os::Linux::gettid());
858 858
859 859 if (UseNUMA) {
860 860 int lgrp_id = os::numa_get_group_id();
861 861 if (lgrp_id != -1) {
862 862 thread->set_lgrp_id(lgrp_id);
863 863 }
864 864 }
865 865 // initialize signal mask for this thread
866 866 os::Linux::hotspot_sigmask(thread);
867 867
868 868 // initialize floating point control register
869 869 os::Linux::init_thread_fpu_state();
870 870
871 871 // handshaking with parent thread
872 872 {
873 873 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
874 874
875 875 // notify parent thread
876 876 osthread->set_state(INITIALIZED);
877 877 sync->notify_all();
878 878
879 879 // wait until os::start_thread()
880 880 while (osthread->get_state() == INITIALIZED) {
881 881 sync->wait(Mutex::_no_safepoint_check_flag);
882 882 }
883 883 }
884 884
885 885 // call one more level start routine
886 886 thread->run();
887 887
888 888 return 0;
889 889 }
890 890
891 891 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
892 892 assert(thread->osthread() == NULL, "caller responsible");
893 893
894 894 // Allocate the OSThread object
895 895 OSThread* osthread = new OSThread(NULL, NULL);
896 896 if (osthread == NULL) {
897 897 return false;
898 898 }
899 899
900 900 // set the correct thread state
901 901 osthread->set_thread_type(thr_type);
902 902
903 903 // Initial state is ALLOCATED but not INITIALIZED
904 904 osthread->set_state(ALLOCATED);
905 905
906 906 thread->set_osthread(osthread);
907 907
908 908 // init thread attributes
909 909 pthread_attr_t attr;
910 910 pthread_attr_init(&attr);
911 911 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
912 912
913 913 // stack size
914 914 if (os::Linux::supports_variable_stack_size()) {
915 915 // calculate stack size if it's not specified by caller
916 916 if (stack_size == 0) {
917 917 stack_size = os::Linux::default_stack_size(thr_type);
918 918
919 919 switch (thr_type) {
920 920 case os::java_thread:
921 921 // Java threads use ThreadStackSize which default value can be
922 922 // changed with the flag -Xss
923 923 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
924 924 stack_size = JavaThread::stack_size_at_create();
925 925 break;
926 926 case os::compiler_thread:
927 927 if (CompilerThreadStackSize > 0) {
928 928 stack_size = (size_t)(CompilerThreadStackSize * K);
929 929 break;
930 930 } // else fall through:
931 931 // use VMThreadStackSize if CompilerThreadStackSize is not defined
932 932 case os::vm_thread:
933 933 case os::pgc_thread:
934 934 case os::cgc_thread:
935 935 case os::watcher_thread:
936 936 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
937 937 break;
938 938 }
939 939 }
940 940
941 941 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
942 942 pthread_attr_setstacksize(&attr, stack_size);
943 943 } else {
944 944 // let pthread_create() pick the default value.
945 945 }
946 946
947 947 // glibc guard page
948 948 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
949 949
950 950 ThreadState state;
951 951
952 952 {
953 953 // Serialize thread creation if we are running with fixed stack LinuxThreads
954 954 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
955 955 if (lock) {
956 956 os::Linux::createThread_lock()->lock_without_safepoint_check();
957 957 }
958 958
959 959 pthread_t tid;
960 960 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
961 961
962 962 pthread_attr_destroy(&attr);
963 963
964 964 if (ret != 0) {
965 965 if (PrintMiscellaneous && (Verbose || WizardMode)) {
966 966 perror("pthread_create()");
967 967 }
968 968 // Need to clean up stuff we've allocated so far
969 969 thread->set_osthread(NULL);
970 970 delete osthread;
971 971 if (lock) os::Linux::createThread_lock()->unlock();
972 972 return false;
973 973 }
974 974
975 975 // Store pthread info into the OSThread
976 976 osthread->set_pthread_id(tid);
977 977
978 978 // Wait until child thread is either initialized or aborted
979 979 {
980 980 Monitor* sync_with_child = osthread->startThread_lock();
981 981 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
982 982 while ((state = osthread->get_state()) == ALLOCATED) {
983 983 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
984 984 }
985 985 }
986 986
987 987 if (lock) {
988 988 os::Linux::createThread_lock()->unlock();
989 989 }
990 990 }
991 991
992 992 // Aborted due to thread limit being reached
993 993 if (state == ZOMBIE) {
994 994 thread->set_osthread(NULL);
995 995 delete osthread;
996 996 return false;
997 997 }
998 998
999 999 // The thread is returned suspended (in state INITIALIZED),
1000 1000 // and is started higher up in the call chain
1001 1001 assert(state == INITIALIZED, "race condition");
1002 1002 return true;
1003 1003 }
1004 1004
1005 1005 /////////////////////////////////////////////////////////////////////////////
1006 1006 // attach existing thread
1007 1007
1008 1008 // bootstrap the main thread
1009 1009 bool os::create_main_thread(JavaThread* thread) {
1010 1010 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1011 1011 return create_attached_thread(thread);
1012 1012 }
1013 1013
1014 1014 bool os::create_attached_thread(JavaThread* thread) {
1015 1015 #ifdef ASSERT
1016 1016 thread->verify_not_published();
1017 1017 #endif
1018 1018
1019 1019 // Allocate the OSThread object
1020 1020 OSThread* osthread = new OSThread(NULL, NULL);
1021 1021
1022 1022 if (osthread == NULL) {
1023 1023 return false;
1024 1024 }
1025 1025
1026 1026 // Store pthread info into the OSThread
1027 1027 osthread->set_thread_id(os::Linux::gettid());
1028 1028 osthread->set_pthread_id(::pthread_self());
1029 1029
1030 1030 // initialize floating point control register
1031 1031 os::Linux::init_thread_fpu_state();
1032 1032
1033 1033 // Initial thread state is RUNNABLE
1034 1034 osthread->set_state(RUNNABLE);
1035 1035
1036 1036 thread->set_osthread(osthread);
1037 1037
1038 1038 if (UseNUMA) {
1039 1039 int lgrp_id = os::numa_get_group_id();
1040 1040 if (lgrp_id != -1) {
1041 1041 thread->set_lgrp_id(lgrp_id);
1042 1042 }
1043 1043 }
1044 1044
1045 1045 if (os::Linux::is_initial_thread()) {
1046 1046 // If current thread is initial thread, its stack is mapped on demand,
1047 1047 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1048 1048 // the entire stack region to avoid SEGV in stack banging.
1049 1049 // It is also useful to get around the heap-stack-gap problem on SuSE
1050 1050 // kernel (see 4821821 for details). We first expand stack to the top
1051 1051 // of yellow zone, then enable stack yellow zone (order is significant,
1052 1052 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1053 1053 // is no gap between the last two virtual memory regions.
1054 1054
1055 1055 JavaThread *jt = (JavaThread *)thread;
1056 1056 address addr = jt->stack_yellow_zone_base();
1057 1057 assert(addr != NULL, "initialization problem?");
1058 1058 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1059 1059
1060 1060 osthread->set_expanding_stack();
1061 1061 os::Linux::manually_expand_stack(jt, addr);
1062 1062 osthread->clear_expanding_stack();
1063 1063 }
1064 1064
1065 1065 // initialize signal mask for this thread
1066 1066 // and save the caller's signal mask
1067 1067 os::Linux::hotspot_sigmask(thread);
1068 1068
1069 1069 return true;
1070 1070 }
1071 1071
1072 1072 void os::pd_start_thread(Thread* thread) {
1073 1073 OSThread * osthread = thread->osthread();
1074 1074 assert(osthread->get_state() != INITIALIZED, "just checking");
1075 1075 Monitor* sync_with_child = osthread->startThread_lock();
1076 1076 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1077 1077 sync_with_child->notify();
1078 1078 }
1079 1079
1080 1080 // Free Linux resources related to the OSThread
1081 1081 void os::free_thread(OSThread* osthread) {
1082 1082 assert(osthread != NULL, "osthread not set");
1083 1083
1084 1084 if (Thread::current()->osthread() == osthread) {
1085 1085 // Restore caller's signal mask
1086 1086 sigset_t sigmask = osthread->caller_sigmask();
1087 1087 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1088 1088 }
1089 1089
1090 1090 delete osthread;
1091 1091 }
1092 1092
1093 1093 //////////////////////////////////////////////////////////////////////////////
1094 1094 // thread local storage
1095 1095
1096 1096 int os::allocate_thread_local_storage() {
1097 1097 pthread_key_t key;
1098 1098 int rslt = pthread_key_create(&key, NULL);
1099 1099 assert(rslt == 0, "cannot allocate thread local storage");
1100 1100 return (int)key;
1101 1101 }
1102 1102
1103 1103 // Note: This is currently not used by VM, as we don't destroy TLS key
1104 1104 // on VM exit.
1105 1105 void os::free_thread_local_storage(int index) {
1106 1106 int rslt = pthread_key_delete((pthread_key_t)index);
1107 1107 assert(rslt == 0, "invalid index");
1108 1108 }
1109 1109
1110 1110 void os::thread_local_storage_at_put(int index, void* value) {
1111 1111 int rslt = pthread_setspecific((pthread_key_t)index, value);
1112 1112 assert(rslt == 0, "pthread_setspecific failed");
1113 1113 }
1114 1114
1115 1115 extern "C" Thread* get_thread() {
1116 1116 return ThreadLocalStorage::thread();
1117 1117 }
1118 1118
1119 1119 //////////////////////////////////////////////////////////////////////////////
1120 1120 // initial thread
1121 1121
1122 1122 // Check if current thread is the initial thread, similar to Solaris thr_main.
1123 1123 bool os::Linux::is_initial_thread(void) {
1124 1124 char dummy;
1125 1125 // If called before init complete, thread stack bottom will be null.
1126 1126 // Can be called if fatal error occurs before initialization.
1127 1127 if (initial_thread_stack_bottom() == NULL) return false;
1128 1128 assert(initial_thread_stack_bottom() != NULL &&
1129 1129 initial_thread_stack_size() != 0,
1130 1130 "os::init did not locate initial thread's stack region");
1131 1131 if ((address)&dummy >= initial_thread_stack_bottom() &&
1132 1132 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1133 1133 return true;
1134 1134 else return false;
1135 1135 }
1136 1136
1137 1137 // Find the virtual memory area that contains addr
1138 1138 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1139 1139 FILE *fp = fopen("/proc/self/maps", "r");
1140 1140 if (fp) {
1141 1141 address low, high;
1142 1142 while (!feof(fp)) {
1143 1143 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1144 1144 if (low <= addr && addr < high) {
1145 1145 if (vma_low) *vma_low = low;
1146 1146 if (vma_high) *vma_high = high;
1147 1147 fclose (fp);
1148 1148 return true;
1149 1149 }
1150 1150 }
1151 1151 for (;;) {
1152 1152 int ch = fgetc(fp);
1153 1153 if (ch == EOF || ch == (int)'\n') break;
1154 1154 }
1155 1155 }
1156 1156 fclose(fp);
1157 1157 }
1158 1158 return false;
1159 1159 }
1160 1160
1161 1161 // Locate initial thread stack. This special handling of initial thread stack
1162 1162 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1163 1163 // bogus value for initial thread.
1164 1164 void os::Linux::capture_initial_stack(size_t max_size) {
1165 1165 // stack size is the easy part, get it from RLIMIT_STACK
1166 1166 size_t stack_size;
1167 1167 struct rlimit rlim;
1168 1168 getrlimit(RLIMIT_STACK, &rlim);
1169 1169 stack_size = rlim.rlim_cur;
1170 1170
1171 1171 // 6308388: a bug in ld.so will relocate its own .data section to the
1172 1172 // lower end of primordial stack; reduce ulimit -s value a little bit
1173 1173 // so we won't install guard page on ld.so's data section.
1174 1174 stack_size -= 2 * page_size();
1175 1175
1176 1176 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1177 1177 // 7.1, in both cases we will get 2G in return value.
1178 1178 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1179 1179 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1180 1180 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1181 1181 // in case other parts in glibc still assumes 2M max stack size.
1182 1182 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1183 1183 #ifndef IA64
1184 1184 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1185 1185 #else
1186 1186 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1187 1187 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1188 1188 #endif
1189 1189
1190 1190 // Try to figure out where the stack base (top) is. This is harder.
1191 1191 //
1192 1192 // When an application is started, glibc saves the initial stack pointer in
1193 1193 // a global variable "__libc_stack_end", which is then used by system
1194 1194 // libraries. __libc_stack_end should be pretty close to stack top. The
1195 1195 // variable is available since the very early days. However, because it is
1196 1196 // a private interface, it could disappear in the future.
1197 1197 //
1198 1198 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1199 1199 // to __libc_stack_end, it is very close to stack top, but isn't the real
1200 1200 // stack top. Note that /proc may not exist if VM is running as a chroot
1201 1201 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1202 1202 // /proc/<pid>/stat could change in the future (though unlikely).
1203 1203 //
1204 1204 // We try __libc_stack_end first. If that doesn't work, look for
1205 1205 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1206 1206 // as a hint, which should work well in most cases.
1207 1207
1208 1208 uintptr_t stack_start;
1209 1209
1210 1210 // try __libc_stack_end first
1211 1211 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1212 1212 if (p && *p) {
1213 1213 stack_start = *p;
1214 1214 } else {
1215 1215 // see if we can get the start_stack field from /proc/self/stat
1216 1216 FILE *fp;
1217 1217 int pid;
1218 1218 char state;
1219 1219 int ppid;
1220 1220 int pgrp;
1221 1221 int session;
1222 1222 int nr;
1223 1223 int tpgrp;
1224 1224 unsigned long flags;
1225 1225 unsigned long minflt;
1226 1226 unsigned long cminflt;
1227 1227 unsigned long majflt;
1228 1228 unsigned long cmajflt;
1229 1229 unsigned long utime;
1230 1230 unsigned long stime;
1231 1231 long cutime;
1232 1232 long cstime;
1233 1233 long prio;
1234 1234 long nice;
1235 1235 long junk;
1236 1236 long it_real;
1237 1237 uintptr_t start;
1238 1238 uintptr_t vsize;
1239 1239 intptr_t rss;
1240 1240 uintptr_t rsslim;
1241 1241 uintptr_t scodes;
1242 1242 uintptr_t ecode;
1243 1243 int i;
1244 1244
1245 1245 // Figure what the primordial thread stack base is. Code is inspired
1246 1246 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1247 1247 // followed by command name surrounded by parentheses, state, etc.
1248 1248 char stat[2048];
1249 1249 int statlen;
1250 1250
1251 1251 fp = fopen("/proc/self/stat", "r");
1252 1252 if (fp) {
1253 1253 statlen = fread(stat, 1, 2047, fp);
1254 1254 stat[statlen] = '\0';
1255 1255 fclose(fp);
1256 1256
1257 1257 // Skip pid and the command string. Note that we could be dealing with
1258 1258 // weird command names, e.g. user could decide to rename java launcher
1259 1259 // to "java 1.4.2 :)", then the stat file would look like
1260 1260 // 1234 (java 1.4.2 :)) R ... ...
1261 1261 // We don't really need to know the command string, just find the last
1262 1262 // occurrence of ")" and then start parsing from there. See bug 4726580.
1263 1263 char * s = strrchr(stat, ')');
1264 1264
1265 1265 i = 0;
1266 1266 if (s) {
1267 1267 // Skip blank chars
1268 1268 do s++; while (isspace(*s));
1269 1269
1270 1270 #define _UFM UINTX_FORMAT
1271 1271 #define _DFM INTX_FORMAT
1272 1272
1273 1273 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1274 1274 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */
1275 1275 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1276 1276 &state, /* 3 %c */
1277 1277 &ppid, /* 4 %d */
1278 1278 &pgrp, /* 5 %d */
1279 1279 &session, /* 6 %d */
1280 1280 &nr, /* 7 %d */
1281 1281 &tpgrp, /* 8 %d */
1282 1282 &flags, /* 9 %lu */
1283 1283 &minflt, /* 10 %lu */
1284 1284 &cminflt, /* 11 %lu */
1285 1285 &majflt, /* 12 %lu */
1286 1286 &cmajflt, /* 13 %lu */
1287 1287 &utime, /* 14 %lu */
1288 1288 &stime, /* 15 %lu */
1289 1289 &cutime, /* 16 %ld */
1290 1290 &cstime, /* 17 %ld */
1291 1291 &prio, /* 18 %ld */
1292 1292 &nice, /* 19 %ld */
1293 1293 &junk, /* 20 %ld */
1294 1294 &it_real, /* 21 %ld */
1295 1295 &start, /* 22 UINTX_FORMAT */
1296 1296 &vsize, /* 23 UINTX_FORMAT */
1297 1297 &rss, /* 24 INTX_FORMAT */
1298 1298 &rsslim, /* 25 UINTX_FORMAT */
1299 1299 &scodes, /* 26 UINTX_FORMAT */
1300 1300 &ecode, /* 27 UINTX_FORMAT */
1301 1301 &stack_start); /* 28 UINTX_FORMAT */
1302 1302 }
1303 1303
1304 1304 #undef _UFM
1305 1305 #undef _DFM
1306 1306
1307 1307 if (i != 28 - 2) {
1308 1308 assert(false, "Bad conversion from /proc/self/stat");
1309 1309 // product mode - assume we are the initial thread, good luck in the
1310 1310 // embedded case.
1311 1311 warning("Can't detect initial thread stack location - bad conversion");
1312 1312 stack_start = (uintptr_t) &rlim;
1313 1313 }
1314 1314 } else {
1315 1315 // For some reason we can't open /proc/self/stat (for example, running on
1316 1316 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1317 1317 // most cases, so don't abort:
1318 1318 warning("Can't detect initial thread stack location - no /proc/self/stat");
1319 1319 stack_start = (uintptr_t) &rlim;
1320 1320 }
1321 1321 }
1322 1322
1323 1323 // Now we have a pointer (stack_start) very close to the stack top, the
1324 1324 // next thing to do is to figure out the exact location of stack top. We
1325 1325 // can find out the virtual memory area that contains stack_start by
1326 1326 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1327 1327 // and its upper limit is the real stack top. (again, this would fail if
1328 1328 // running inside chroot, because /proc may not exist.)
1329 1329
1330 1330 uintptr_t stack_top;
1331 1331 address low, high;
1332 1332 if (find_vma((address)stack_start, &low, &high)) {
1333 1333 // success, "high" is the true stack top. (ignore "low", because initial
1334 1334 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1335 1335 stack_top = (uintptr_t)high;
1336 1336 } else {
1337 1337 // failed, likely because /proc/self/maps does not exist
1338 1338 warning("Can't detect initial thread stack location - find_vma failed");
1339 1339 // best effort: stack_start is normally within a few pages below the real
1340 1340 // stack top, use it as stack top, and reduce stack size so we won't put
1341 1341 // guard page outside stack.
1342 1342 stack_top = stack_start;
1343 1343 stack_size -= 16 * page_size();
1344 1344 }
1345 1345
1346 1346 // stack_top could be partially down the page so align it
1347 1347 stack_top = align_size_up(stack_top, page_size());
1348 1348
1349 1349 if (max_size && stack_size > max_size) {
1350 1350 _initial_thread_stack_size = max_size;
1351 1351 } else {
1352 1352 _initial_thread_stack_size = stack_size;
1353 1353 }
1354 1354
1355 1355 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1356 1356 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1357 1357 }
1358 1358
1359 1359 ////////////////////////////////////////////////////////////////////////////////
1360 1360 // time support
1361 1361
1362 1362 // Time since start-up in seconds to a fine granularity.
1363 1363 // Used by VMSelfDestructTimer and the MemProfiler.
1364 1364 double os::elapsedTime() {
1365 1365
1366 1366 return (double)(os::elapsed_counter()) * 0.000001;
1367 1367 }
1368 1368
1369 1369 jlong os::elapsed_counter() {
1370 1370 timeval time;
1371 1371 int status = gettimeofday(&time, NULL);
1372 1372 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1373 1373 }
1374 1374
1375 1375 jlong os::elapsed_frequency() {
1376 1376 return (1000 * 1000);
1377 1377 }
1378 1378
1379 1379 // For now, we say that linux does not support vtime. I have no idea
1380 1380 // whether it can actually be made to (DLD, 9/13/05).
1381 1381
1382 1382 bool os::supports_vtime() { return false; }
1383 1383 bool os::enable_vtime() { return false; }
1384 1384 bool os::vtime_enabled() { return false; }
1385 1385 double os::elapsedVTime() {
1386 1386 // better than nothing, but not much
1387 1387 return elapsedTime();
1388 1388 }
1389 1389
1390 1390 jlong os::javaTimeMillis() {
1391 1391 timeval time;
1392 1392 int status = gettimeofday(&time, NULL);
1393 1393 assert(status != -1, "linux error");
1394 1394 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1395 1395 }
1396 1396
1397 1397 #ifndef CLOCK_MONOTONIC
1398 1398 #define CLOCK_MONOTONIC (1)
1399 1399 #endif
1400 1400
1401 1401 void os::Linux::clock_init() {
1402 1402 // we do dlopen's in this particular order due to bug in linux
1403 1403 // dynamical loader (see 6348968) leading to crash on exit
1404 1404 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1405 1405 if (handle == NULL) {
1406 1406 handle = dlopen("librt.so", RTLD_LAZY);
1407 1407 }
1408 1408
1409 1409 if (handle) {
1410 1410 int (*clock_getres_func)(clockid_t, struct timespec*) =
1411 1411 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1412 1412 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1413 1413 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1414 1414 if (clock_getres_func && clock_gettime_func) {
1415 1415 // See if monotonic clock is supported by the kernel. Note that some
1416 1416 // early implementations simply return kernel jiffies (updated every
1417 1417 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1418 1418 // for nano time (though the monotonic property is still nice to have).
1419 1419 // It's fixed in newer kernels, however clock_getres() still returns
1420 1420 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1421 1421 // resolution for now. Hopefully as people move to new kernels, this
1422 1422 // won't be a problem.
1423 1423 struct timespec res;
1424 1424 struct timespec tp;
1425 1425 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1426 1426 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1427 1427 // yes, monotonic clock is supported
1428 1428 _clock_gettime = clock_gettime_func;
1429 1429 } else {
1430 1430 // close librt if there is no monotonic clock
1431 1431 dlclose(handle);
1432 1432 }
1433 1433 }
1434 1434 }
1435 1435 }
1436 1436
1437 1437 #ifndef SYS_clock_getres
1438 1438
1439 1439 #if defined(IA32) || defined(AMD64)
1440 1440 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1441 1441 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1442 1442 #else
1443 1443 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1444 1444 #define sys_clock_getres(x,y) -1
1445 1445 #endif
1446 1446
1447 1447 #else
1448 1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1449 1449 #endif
1450 1450
1451 1451 void os::Linux::fast_thread_clock_init() {
1452 1452 if (!UseLinuxPosixThreadCPUClocks) {
1453 1453 return;
1454 1454 }
1455 1455 clockid_t clockid;
1456 1456 struct timespec tp;
1457 1457 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1458 1458 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1459 1459
1460 1460 // Switch to using fast clocks for thread cpu time if
1461 1461 // the sys_clock_getres() returns 0 error code.
1462 1462 // Note, that some kernels may support the current thread
1463 1463 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1464 1464 // returned by the pthread_getcpuclockid().
1465 1465 // If the fast Posix clocks are supported then the sys_clock_getres()
1466 1466 // must return at least tp.tv_sec == 0 which means a resolution
1467 1467 // better than 1 sec. This is extra check for reliability.
1468 1468
1469 1469 if(pthread_getcpuclockid_func &&
1470 1470 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1471 1471 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1472 1472
1473 1473 _supports_fast_thread_cpu_time = true;
1474 1474 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1475 1475 }
1476 1476 }
1477 1477
1478 1478 jlong os::javaTimeNanos() {
1479 1479 if (Linux::supports_monotonic_clock()) {
1480 1480 struct timespec tp;
1481 1481 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1482 1482 assert(status == 0, "gettime error");
1483 1483 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1484 1484 return result;
1485 1485 } else {
1486 1486 timeval time;
1487 1487 int status = gettimeofday(&time, NULL);
1488 1488 assert(status != -1, "linux error");
1489 1489 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1490 1490 return 1000 * usecs;
1491 1491 }
1492 1492 }
1493 1493
1494 1494 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1495 1495 if (Linux::supports_monotonic_clock()) {
1496 1496 info_ptr->max_value = ALL_64_BITS;
1497 1497
1498 1498 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1499 1499 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1500 1500 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1501 1501 } else {
1502 1502 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1503 1503 info_ptr->max_value = ALL_64_BITS;
1504 1504
1505 1505 // gettimeofday is a real time clock so it skips
1506 1506 info_ptr->may_skip_backward = true;
1507 1507 info_ptr->may_skip_forward = true;
1508 1508 }
1509 1509
1510 1510 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1511 1511 }
1512 1512
1513 1513 // Return the real, user, and system times in seconds from an
1514 1514 // arbitrary fixed point in the past.
1515 1515 bool os::getTimesSecs(double* process_real_time,
1516 1516 double* process_user_time,
1517 1517 double* process_system_time) {
1518 1518 struct tms ticks;
1519 1519 clock_t real_ticks = times(&ticks);
1520 1520
1521 1521 if (real_ticks == (clock_t) (-1)) {
1522 1522 return false;
1523 1523 } else {
1524 1524 double ticks_per_second = (double) clock_tics_per_sec;
1525 1525 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1526 1526 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1527 1527 *process_real_time = ((double) real_ticks) / ticks_per_second;
1528 1528
1529 1529 return true;
1530 1530 }
1531 1531 }
1532 1532
1533 1533
1534 1534 char * os::local_time_string(char *buf, size_t buflen) {
1535 1535 struct tm t;
1536 1536 time_t long_time;
1537 1537 time(&long_time);
1538 1538 localtime_r(&long_time, &t);
1539 1539 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1540 1540 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1541 1541 t.tm_hour, t.tm_min, t.tm_sec);
1542 1542 return buf;
1543 1543 }
1544 1544
1545 1545 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1546 1546 return localtime_r(clock, res);
1547 1547 }
1548 1548
1549 1549 ////////////////////////////////////////////////////////////////////////////////
1550 1550 // runtime exit support
1551 1551
1552 1552 // Note: os::shutdown() might be called very early during initialization, or
1553 1553 // called from signal handler. Before adding something to os::shutdown(), make
1554 1554 // sure it is async-safe and can handle partially initialized VM.
1555 1555 void os::shutdown() {
1556 1556
1557 1557 // allow PerfMemory to attempt cleanup of any persistent resources
1558 1558 perfMemory_exit();
1559 1559
1560 1560 // needs to remove object in file system
1561 1561 AttachListener::abort();
1562 1562
1563 1563 // flush buffered output, finish log files
1564 1564 ostream_abort();
1565 1565
1566 1566 // Check for abort hook
1567 1567 abort_hook_t abort_hook = Arguments::abort_hook();
1568 1568 if (abort_hook != NULL) {
1569 1569 abort_hook();
1570 1570 }
1571 1571
1572 1572 }
1573 1573
1574 1574 // Note: os::abort() might be called very early during initialization, or
1575 1575 // called from signal handler. Before adding something to os::abort(), make
1576 1576 // sure it is async-safe and can handle partially initialized VM.
1577 1577 void os::abort(bool dump_core) {
1578 1578 os::shutdown();
1579 1579 if (dump_core) {
1580 1580 #ifndef PRODUCT
1581 1581 fdStream out(defaultStream::output_fd());
1582 1582 out.print_raw("Current thread is ");
1583 1583 char buf[16];
1584 1584 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1585 1585 out.print_raw_cr(buf);
1586 1586 out.print_raw_cr("Dumping core ...");
1587 1587 #endif
1588 1588 ::abort(); // dump core
1589 1589 }
1590 1590
1591 1591 ::exit(1);
1592 1592 }
1593 1593
1594 1594 // Die immediately, no exit hook, no abort hook, no cleanup.
1595 1595 void os::die() {
1596 1596 // _exit() on LinuxThreads only kills current thread
1597 1597 ::abort();
1598 1598 }
1599 1599
1600 1600 // unused on linux for now.
1601 1601 void os::set_error_file(const char *logfile) {}
1602 1602
1603 1603
1604 1604 // This method is a copy of JDK's sysGetLastErrorString
1605 1605 // from src/solaris/hpi/src/system_md.c
1606 1606
1607 1607 size_t os::lasterror(char *buf, size_t len) {
1608 1608
1609 1609 if (errno == 0) return 0;
1610 1610
1611 1611 const char *s = ::strerror(errno);
1612 1612 size_t n = ::strlen(s);
1613 1613 if (n >= len) {
1614 1614 n = len - 1;
1615 1615 }
1616 1616 ::strncpy(buf, s, n);
1617 1617 buf[n] = '\0';
1618 1618 return n;
1619 1619 }
1620 1620
1621 1621 intx os::current_thread_id() { return (intx)pthread_self(); }
1622 1622 int os::current_process_id() {
1623 1623
1624 1624 // Under the old linux thread library, linux gives each thread
1625 1625 // its own process id. Because of this each thread will return
1626 1626 // a different pid if this method were to return the result
1627 1627 // of getpid(2). Linux provides no api that returns the pid
1628 1628 // of the launcher thread for the vm. This implementation
1629 1629 // returns a unique pid, the pid of the launcher thread
1630 1630 // that starts the vm 'process'.
1631 1631
1632 1632 // Under the NPTL, getpid() returns the same pid as the
1633 1633 // launcher thread rather than a unique pid per thread.
1634 1634 // Use gettid() if you want the old pre NPTL behaviour.
1635 1635
1636 1636 // if you are looking for the result of a call to getpid() that
1637 1637 // returns a unique pid for the calling thread, then look at the
1638 1638 // OSThread::thread_id() method in osThread_linux.hpp file
1639 1639
1640 1640 return (int)(_initial_pid ? _initial_pid : getpid());
1641 1641 }
1642 1642
1643 1643 // DLL functions
1644 1644
1645 1645 const char* os::dll_file_extension() { return ".so"; }
1646 1646
1647 1647 // This must be hard coded because it's the system's temporary
1648 1648 // directory not the java application's temp directory, ala java.io.tmpdir.
1649 1649 const char* os::get_temp_directory() { return "/tmp"; }
1650 1650
1651 1651 static bool file_exists(const char* filename) {
1652 1652 struct stat statbuf;
1653 1653 if (filename == NULL || strlen(filename) == 0) {
1654 1654 return false;
1655 1655 }
1656 1656 return os::stat(filename, &statbuf) == 0;
1657 1657 }
1658 1658
1659 1659 void os::dll_build_name(char* buffer, size_t buflen,
1660 1660 const char* pname, const char* fname) {
1661 1661 // Copied from libhpi
1662 1662 const size_t pnamelen = pname ? strlen(pname) : 0;
1663 1663
1664 1664 // Quietly truncate on buffer overflow. Should be an error.
1665 1665 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1666 1666 *buffer = '\0';
1667 1667 return;
1668 1668 }
1669 1669
1670 1670 if (pnamelen == 0) {
1671 1671 snprintf(buffer, buflen, "lib%s.so", fname);
1672 1672 } else if (strchr(pname, *os::path_separator()) != NULL) {
1673 1673 int n;
1674 1674 char** pelements = split_path(pname, &n);
1675 1675 for (int i = 0 ; i < n ; i++) {
1676 1676 // Really shouldn't be NULL, but check can't hurt
1677 1677 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1678 1678 continue; // skip the empty path values
1679 1679 }
1680 1680 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1681 1681 if (file_exists(buffer)) {
1682 1682 break;
1683 1683 }
1684 1684 }
1685 1685 // release the storage
1686 1686 for (int i = 0 ; i < n ; i++) {
1687 1687 if (pelements[i] != NULL) {
1688 1688 FREE_C_HEAP_ARRAY(char, pelements[i]);
1689 1689 }
1690 1690 }
1691 1691 if (pelements != NULL) {
1692 1692 FREE_C_HEAP_ARRAY(char*, pelements);
1693 1693 }
1694 1694 } else {
1695 1695 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1696 1696 }
1697 1697 }
1698 1698
1699 1699 const char* os::get_current_directory(char *buf, int buflen) {
1700 1700 return getcwd(buf, buflen);
1701 1701 }
1702 1702
1703 1703 // check if addr is inside libjvm[_g].so
1704 1704 bool os::address_is_in_vm(address addr) {
1705 1705 static address libjvm_base_addr;
1706 1706 Dl_info dlinfo;
1707 1707
1708 1708 if (libjvm_base_addr == NULL) {
1709 1709 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1710 1710 libjvm_base_addr = (address)dlinfo.dli_fbase;
1711 1711 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1712 1712 }
1713 1713
1714 1714 if (dladdr((void *)addr, &dlinfo)) {
1715 1715 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1716 1716 }
1717 1717
1718 1718 return false;
1719 1719 }
1720 1720
1721 1721 bool os::dll_address_to_function_name(address addr, char *buf,
1722 1722 int buflen, int *offset) {
1723 1723 Dl_info dlinfo;
1724 1724
1725 1725 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1726 1726 if (buf != NULL) {
1727 1727 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1728 1728 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1729 1729 }
1730 1730 }
1731 1731 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1732 1732 return true;
1733 1733 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1734 1734 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1735 1735 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) {
1736 1736 return true;
1737 1737 }
1738 1738 }
1739 1739
1740 1740 if (buf != NULL) buf[0] = '\0';
1741 1741 if (offset != NULL) *offset = -1;
1742 1742 return false;
1743 1743 }
1744 1744
1745 1745 struct _address_to_library_name {
1746 1746 address addr; // input : memory address
1747 1747 size_t buflen; // size of fname
1748 1748 char* fname; // output: library name
1749 1749 address base; // library base addr
1750 1750 };
1751 1751
1752 1752 static int address_to_library_name_callback(struct dl_phdr_info *info,
1753 1753 size_t size, void *data) {
1754 1754 int i;
1755 1755 bool found = false;
1756 1756 address libbase = NULL;
1757 1757 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1758 1758
1759 1759 // iterate through all loadable segments
1760 1760 for (i = 0; i < info->dlpi_phnum; i++) {
1761 1761 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1762 1762 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1763 1763 // base address of a library is the lowest address of its loaded
1764 1764 // segments.
1765 1765 if (libbase == NULL || libbase > segbase) {
1766 1766 libbase = segbase;
1767 1767 }
1768 1768 // see if 'addr' is within current segment
1769 1769 if (segbase <= d->addr &&
1770 1770 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1771 1771 found = true;
1772 1772 }
1773 1773 }
1774 1774 }
1775 1775
1776 1776 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1777 1777 // so dll_address_to_library_name() can fall through to use dladdr() which
1778 1778 // can figure out executable name from argv[0].
1779 1779 if (found && info->dlpi_name && info->dlpi_name[0]) {
1780 1780 d->base = libbase;
1781 1781 if (d->fname) {
1782 1782 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1783 1783 }
1784 1784 return 1;
1785 1785 }
1786 1786 return 0;
1787 1787 }
1788 1788
1789 1789 bool os::dll_address_to_library_name(address addr, char* buf,
1790 1790 int buflen, int* offset) {
1791 1791 Dl_info dlinfo;
1792 1792 struct _address_to_library_name data;
1793 1793
1794 1794 // There is a bug in old glibc dladdr() implementation that it could resolve
1795 1795 // to wrong library name if the .so file has a base address != NULL. Here
1796 1796 // we iterate through the program headers of all loaded libraries to find
1797 1797 // out which library 'addr' really belongs to. This workaround can be
1798 1798 // removed once the minimum requirement for glibc is moved to 2.3.x.
1799 1799 data.addr = addr;
1800 1800 data.fname = buf;
1801 1801 data.buflen = buflen;
1802 1802 data.base = NULL;
1803 1803 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1804 1804
1805 1805 if (rslt) {
1806 1806 // buf already contains library name
1807 1807 if (offset) *offset = addr - data.base;
1808 1808 return true;
1809 1809 } else if (dladdr((void*)addr, &dlinfo)){
1810 1810 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1811 1811 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1812 1812 return true;
1813 1813 } else {
1814 1814 if (buf) buf[0] = '\0';
1815 1815 if (offset) *offset = -1;
1816 1816 return false;
1817 1817 }
1818 1818 }
1819 1819
1820 1820 // Loads .dll/.so and
1821 1821 // in case of error it checks if .dll/.so was built for the
1822 1822 // same architecture as Hotspot is running on
1823 1823
1824 1824 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1825 1825 {
1826 1826 void * result= ::dlopen(filename, RTLD_LAZY);
1827 1827 if (result != NULL) {
1828 1828 // Successful loading
1829 1829 return result;
1830 1830 }
1831 1831
1832 1832 Elf32_Ehdr elf_head;
1833 1833
1834 1834 // Read system error message into ebuf
1835 1835 // It may or may not be overwritten below
1836 1836 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1837 1837 ebuf[ebuflen-1]='\0';
1838 1838 int diag_msg_max_length=ebuflen-strlen(ebuf);
1839 1839 char* diag_msg_buf=ebuf+strlen(ebuf);
1840 1840
1841 1841 if (diag_msg_max_length==0) {
1842 1842 // No more space in ebuf for additional diagnostics message
1843 1843 return NULL;
1844 1844 }
1845 1845
1846 1846
1847 1847 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1848 1848
1849 1849 if (file_descriptor < 0) {
1850 1850 // Can't open library, report dlerror() message
1851 1851 return NULL;
1852 1852 }
1853 1853
1854 1854 bool failed_to_read_elf_head=
1855 1855 (sizeof(elf_head)!=
1856 1856 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1857 1857
1858 1858 ::close(file_descriptor);
1859 1859 if (failed_to_read_elf_head) {
1860 1860 // file i/o error - report dlerror() msg
1861 1861 return NULL;
1862 1862 }
1863 1863
1864 1864 typedef struct {
1865 1865 Elf32_Half code; // Actual value as defined in elf.h
1866 1866 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1867 1867 char elf_class; // 32 or 64 bit
1868 1868 char endianess; // MSB or LSB
1869 1869 char* name; // String representation
1870 1870 } arch_t;
1871 1871
1872 1872 #ifndef EM_486
1873 1873 #define EM_486 6 /* Intel 80486 */
1874 1874 #endif
1875 1875
1876 1876 static const arch_t arch_array[]={
1877 1877 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1878 1878 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1879 1879 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1880 1880 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1881 1881 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1882 1882 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1883 1883 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1884 1884 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1885 1885 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1886 1886 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1887 1887 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1888 1888 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1889 1889 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1890 1890 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1891 1891 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1892 1892 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1893 1893 };
1894 1894
1895 1895 #if (defined IA32)
1896 1896 static Elf32_Half running_arch_code=EM_386;
1897 1897 #elif (defined AMD64)
1898 1898 static Elf32_Half running_arch_code=EM_X86_64;
1899 1899 #elif (defined IA64)
1900 1900 static Elf32_Half running_arch_code=EM_IA_64;
1901 1901 #elif (defined __sparc) && (defined _LP64)
1902 1902 static Elf32_Half running_arch_code=EM_SPARCV9;
1903 1903 #elif (defined __sparc) && (!defined _LP64)
1904 1904 static Elf32_Half running_arch_code=EM_SPARC;
1905 1905 #elif (defined __powerpc64__)
1906 1906 static Elf32_Half running_arch_code=EM_PPC64;
1907 1907 #elif (defined __powerpc__)
1908 1908 static Elf32_Half running_arch_code=EM_PPC;
1909 1909 #elif (defined ARM)
1910 1910 static Elf32_Half running_arch_code=EM_ARM;
1911 1911 #elif (defined S390)
1912 1912 static Elf32_Half running_arch_code=EM_S390;
1913 1913 #elif (defined ALPHA)
1914 1914 static Elf32_Half running_arch_code=EM_ALPHA;
1915 1915 #elif (defined MIPSEL)
1916 1916 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1917 1917 #elif (defined PARISC)
1918 1918 static Elf32_Half running_arch_code=EM_PARISC;
1919 1919 #elif (defined MIPS)
1920 1920 static Elf32_Half running_arch_code=EM_MIPS;
1921 1921 #elif (defined M68K)
1922 1922 static Elf32_Half running_arch_code=EM_68K;
1923 1923 #else
1924 1924 #error Method os::dll_load requires that one of following is defined:\
1925 1925 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1926 1926 #endif
1927 1927
1928 1928 // Identify compatability class for VM's architecture and library's architecture
1929 1929 // Obtain string descriptions for architectures
1930 1930
1931 1931 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1932 1932 int running_arch_index=-1;
1933 1933
1934 1934 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1935 1935 if (running_arch_code == arch_array[i].code) {
1936 1936 running_arch_index = i;
1937 1937 }
1938 1938 if (lib_arch.code == arch_array[i].code) {
1939 1939 lib_arch.compat_class = arch_array[i].compat_class;
1940 1940 lib_arch.name = arch_array[i].name;
1941 1941 }
1942 1942 }
1943 1943
1944 1944 assert(running_arch_index != -1,
1945 1945 "Didn't find running architecture code (running_arch_code) in arch_array");
1946 1946 if (running_arch_index == -1) {
1947 1947 // Even though running architecture detection failed
1948 1948 // we may still continue with reporting dlerror() message
1949 1949 return NULL;
1950 1950 }
1951 1951
1952 1952 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1953 1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1954 1954 return NULL;
1955 1955 }
1956 1956
1957 1957 #ifndef S390
1958 1958 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1959 1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1960 1960 return NULL;
1961 1961 }
1962 1962 #endif // !S390
1963 1963
1964 1964 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1965 1965 if ( lib_arch.name!=NULL ) {
1966 1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1967 1967 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1968 1968 lib_arch.name, arch_array[running_arch_index].name);
1969 1969 } else {
1970 1970 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1971 1971 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1972 1972 lib_arch.code,
1973 1973 arch_array[running_arch_index].name);
1974 1974 }
1975 1975 }
1976 1976
1977 1977 return NULL;
1978 1978 }
1979 1979
1980 1980 /*
1981 1981 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1982 1982 * chances are you might want to run the generated bits against glibc-2.0
1983 1983 * libdl.so, so always use locking for any version of glibc.
1984 1984 */
1985 1985 void* os::dll_lookup(void* handle, const char* name) {
1986 1986 pthread_mutex_lock(&dl_mutex);
1987 1987 void* res = dlsym(handle, name);
1988 1988 pthread_mutex_unlock(&dl_mutex);
1989 1989 return res;
1990 1990 }
1991 1991
1992 1992
1993 1993 static bool _print_ascii_file(const char* filename, outputStream* st) {
1994 1994 int fd = ::open(filename, O_RDONLY);
1995 1995 if (fd == -1) {
1996 1996 return false;
1997 1997 }
1998 1998
1999 1999 char buf[32];
2000 2000 int bytes;
2001 2001 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2002 2002 st->print_raw(buf, bytes);
2003 2003 }
2004 2004
2005 2005 ::close(fd);
2006 2006
2007 2007 return true;
2008 2008 }
2009 2009
2010 2010 void os::print_dll_info(outputStream *st) {
2011 2011 st->print_cr("Dynamic libraries:");
2012 2012
2013 2013 char fname[32];
2014 2014 pid_t pid = os::Linux::gettid();
2015 2015
2016 2016 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2017 2017
2018 2018 if (!_print_ascii_file(fname, st)) {
2019 2019 st->print("Can not get library information for pid = %d\n", pid);
2020 2020 }
2021 2021 }
2022 2022
2023 2023
2024 2024 void os::print_os_info(outputStream* st) {
2025 2025 st->print("OS:");
2026 2026
2027 2027 // Try to identify popular distros.
2028 2028 // Most Linux distributions have /etc/XXX-release file, which contains
2029 2029 // the OS version string. Some have more than one /etc/XXX-release file
2030 2030 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2031 2031 // so the order is important.
2032 2032 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2033 2033 !_print_ascii_file("/etc/sun-release", st) &&
2034 2034 !_print_ascii_file("/etc/redhat-release", st) &&
2035 2035 !_print_ascii_file("/etc/SuSE-release", st) &&
2036 2036 !_print_ascii_file("/etc/turbolinux-release", st) &&
2037 2037 !_print_ascii_file("/etc/gentoo-release", st) &&
2038 2038 !_print_ascii_file("/etc/debian_version", st) &&
2039 2039 !_print_ascii_file("/etc/ltib-release", st) &&
2040 2040 !_print_ascii_file("/etc/angstrom-version", st)) {
2041 2041 st->print("Linux");
2042 2042 }
2043 2043 st->cr();
2044 2044
2045 2045 // kernel
2046 2046 st->print("uname:");
2047 2047 struct utsname name;
2048 2048 uname(&name);
2049 2049 st->print(name.sysname); st->print(" ");
2050 2050 st->print(name.release); st->print(" ");
2051 2051 st->print(name.version); st->print(" ");
2052 2052 st->print(name.machine);
2053 2053 st->cr();
2054 2054
2055 2055 // Print warning if unsafe chroot environment detected
2056 2056 if (unsafe_chroot_detected) {
2057 2057 st->print("WARNING!! ");
2058 2058 st->print_cr(unstable_chroot_error);
2059 2059 }
2060 2060
2061 2061 // libc, pthread
2062 2062 st->print("libc:");
2063 2063 st->print(os::Linux::glibc_version()); st->print(" ");
2064 2064 st->print(os::Linux::libpthread_version()); st->print(" ");
2065 2065 if (os::Linux::is_LinuxThreads()) {
2066 2066 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2067 2067 }
2068 2068 st->cr();
2069 2069
2070 2070 // rlimit
2071 2071 st->print("rlimit:");
2072 2072 struct rlimit rlim;
2073 2073
2074 2074 st->print(" STACK ");
2075 2075 getrlimit(RLIMIT_STACK, &rlim);
2076 2076 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2077 2077 else st->print("%uk", rlim.rlim_cur >> 10);
2078 2078
2079 2079 st->print(", CORE ");
2080 2080 getrlimit(RLIMIT_CORE, &rlim);
2081 2081 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2082 2082 else st->print("%uk", rlim.rlim_cur >> 10);
2083 2083
2084 2084 st->print(", NPROC ");
2085 2085 getrlimit(RLIMIT_NPROC, &rlim);
2086 2086 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2087 2087 else st->print("%d", rlim.rlim_cur);
2088 2088
2089 2089 st->print(", NOFILE ");
2090 2090 getrlimit(RLIMIT_NOFILE, &rlim);
2091 2091 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2092 2092 else st->print("%d", rlim.rlim_cur);
2093 2093
2094 2094 st->print(", AS ");
2095 2095 getrlimit(RLIMIT_AS, &rlim);
2096 2096 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2097 2097 else st->print("%uk", rlim.rlim_cur >> 10);
2098 2098 st->cr();
2099 2099
2100 2100 // load average
2101 2101 st->print("load average:");
2102 2102 double loadavg[3];
2103 2103 os::loadavg(loadavg, 3);
2104 2104 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2105 2105 st->cr();
2106 2106
2107 2107 // meminfo
2108 2108 st->print("\n/proc/meminfo:\n");
2109 2109 _print_ascii_file("/proc/meminfo", st);
2110 2110 st->cr();
2111 2111 }
2112 2112
2113 2113 void os::pd_print_cpu_info(outputStream* st) {
2114 2114 st->print("\n/proc/cpuinfo:\n");
2115 2115 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2116 2116 st->print(" <Not Available>");
2117 2117 }
2118 2118 st->cr();
2119 2119 }
2120 2120
2121 2121 void os::print_memory_info(outputStream* st) {
2122 2122
2123 2123 st->print("Memory:");
2124 2124 st->print(" %dk page", os::vm_page_size()>>10);
2125 2125
2126 2126 // values in struct sysinfo are "unsigned long"
2127 2127 struct sysinfo si;
2128 2128 sysinfo(&si);
2129 2129
2130 2130 st->print(", physical " UINT64_FORMAT "k",
2131 2131 os::physical_memory() >> 10);
2132 2132 st->print("(" UINT64_FORMAT "k free)",
2133 2133 os::available_memory() >> 10);
2134 2134 st->print(", swap " UINT64_FORMAT "k",
2135 2135 ((jlong)si.totalswap * si.mem_unit) >> 10);
2136 2136 st->print("(" UINT64_FORMAT "k free)",
2137 2137 ((jlong)si.freeswap * si.mem_unit) >> 10);
2138 2138 st->cr();
2139 2139 }
2140 2140
2141 2141 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2142 2142 // but they're the same for all the linux arch that we support
2143 2143 // and they're the same for solaris but there's no common place to put this.
2144 2144 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2145 2145 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2146 2146 "ILL_COPROC", "ILL_BADSTK" };
2147 2147
2148 2148 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2149 2149 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2150 2150 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2151 2151
2152 2152 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2153 2153
2154 2154 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2155 2155
2156 2156 void os::print_siginfo(outputStream* st, void* siginfo) {
2157 2157 st->print("siginfo:");
2158 2158
2159 2159 const int buflen = 100;
2160 2160 char buf[buflen];
2161 2161 siginfo_t *si = (siginfo_t*)siginfo;
2162 2162 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2163 2163 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2164 2164 st->print("si_errno=%s", buf);
2165 2165 } else {
2166 2166 st->print("si_errno=%d", si->si_errno);
2167 2167 }
2168 2168 const int c = si->si_code;
2169 2169 assert(c > 0, "unexpected si_code");
2170 2170 switch (si->si_signo) {
2171 2171 case SIGILL:
2172 2172 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2173 2173 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2174 2174 break;
2175 2175 case SIGFPE:
2176 2176 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2177 2177 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2178 2178 break;
2179 2179 case SIGSEGV:
2180 2180 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2181 2181 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2182 2182 break;
2183 2183 case SIGBUS:
2184 2184 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2185 2185 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2186 2186 break;
2187 2187 default:
2188 2188 st->print(", si_code=%d", si->si_code);
2189 2189 // no si_addr
2190 2190 }
2191 2191
2192 2192 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2193 2193 UseSharedSpaces) {
2194 2194 FileMapInfo* mapinfo = FileMapInfo::current_info();
2195 2195 if (mapinfo->is_in_shared_space(si->si_addr)) {
2196 2196 st->print("\n\nError accessing class data sharing archive." \
2197 2197 " Mapped file inaccessible during execution, " \
2198 2198 " possible disk/network problem.");
2199 2199 }
2200 2200 }
2201 2201 st->cr();
2202 2202 }
2203 2203
2204 2204
2205 2205 static void print_signal_handler(outputStream* st, int sig,
2206 2206 char* buf, size_t buflen);
2207 2207
2208 2208 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2209 2209 st->print_cr("Signal Handlers:");
2210 2210 print_signal_handler(st, SIGSEGV, buf, buflen);
2211 2211 print_signal_handler(st, SIGBUS , buf, buflen);
2212 2212 print_signal_handler(st, SIGFPE , buf, buflen);
2213 2213 print_signal_handler(st, SIGPIPE, buf, buflen);
2214 2214 print_signal_handler(st, SIGXFSZ, buf, buflen);
2215 2215 print_signal_handler(st, SIGILL , buf, buflen);
2216 2216 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2217 2217 print_signal_handler(st, SR_signum, buf, buflen);
2218 2218 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2219 2219 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2220 2220 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2221 2221 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2222 2222 }
2223 2223
2224 2224 static char saved_jvm_path[MAXPATHLEN] = {0};
2225 2225
2226 2226 // Find the full path to the current module, libjvm.so or libjvm_g.so
2227 2227 void os::jvm_path(char *buf, jint buflen) {
2228 2228 // Error checking.
2229 2229 if (buflen < MAXPATHLEN) {
2230 2230 assert(false, "must use a large-enough buffer");
2231 2231 buf[0] = '\0';
2232 2232 return;
2233 2233 }
2234 2234 // Lazy resolve the path to current module.
2235 2235 if (saved_jvm_path[0] != 0) {
2236 2236 strcpy(buf, saved_jvm_path);
2237 2237 return;
2238 2238 }
2239 2239
2240 2240 char dli_fname[MAXPATHLEN];
2241 2241 bool ret = dll_address_to_library_name(
2242 2242 CAST_FROM_FN_PTR(address, os::jvm_path),
2243 2243 dli_fname, sizeof(dli_fname), NULL);
2244 2244 assert(ret != 0, "cannot locate libjvm");
2245 2245 char *rp = realpath(dli_fname, buf);
2246 2246 if (rp == NULL)
2247 2247 return;
2248 2248
2249 2249 if (Arguments::created_by_gamma_launcher()) {
2250 2250 // Support for the gamma launcher. Typical value for buf is
2251 2251 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2252 2252 // the right place in the string, then assume we are installed in a JDK and
2253 2253 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2254 2254 // up the path so it looks like libjvm.so is installed there (append a
2255 2255 // fake suffix hotspot/libjvm.so).
2256 2256 const char *p = buf + strlen(buf) - 1;
2257 2257 for (int count = 0; p > buf && count < 5; ++count) {
2258 2258 for (--p; p > buf && *p != '/'; --p)
2259 2259 /* empty */ ;
2260 2260 }
2261 2261
2262 2262 if (strncmp(p, "/jre/lib/", 9) != 0) {
2263 2263 // Look for JAVA_HOME in the environment.
2264 2264 char* java_home_var = ::getenv("JAVA_HOME");
2265 2265 if (java_home_var != NULL && java_home_var[0] != 0) {
2266 2266 char* jrelib_p;
2267 2267 int len;
2268 2268
2269 2269 // Check the current module name "libjvm.so" or "libjvm_g.so".
2270 2270 p = strrchr(buf, '/');
2271 2271 assert(strstr(p, "/libjvm") == p, "invalid library name");
2272 2272 p = strstr(p, "_g") ? "_g" : "";
2273 2273
2274 2274 rp = realpath(java_home_var, buf);
2275 2275 if (rp == NULL)
2276 2276 return;
2277 2277
2278 2278 // determine if this is a legacy image or modules image
2279 2279 // modules image doesn't have "jre" subdirectory
2280 2280 len = strlen(buf);
2281 2281 jrelib_p = buf + len;
2282 2282 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2283 2283 if (0 != access(buf, F_OK)) {
2284 2284 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2285 2285 }
2286 2286
2287 2287 if (0 == access(buf, F_OK)) {
2288 2288 // Use current module name "libjvm[_g].so" instead of
2289 2289 // "libjvm"debug_only("_g")".so" since for fastdebug version
2290 2290 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2291 2291 len = strlen(buf);
2292 2292 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2293 2293 } else {
2294 2294 // Go back to path of .so
2295 2295 rp = realpath(dli_fname, buf);
2296 2296 if (rp == NULL)
2297 2297 return;
2298 2298 }
2299 2299 }
2300 2300 }
2301 2301 }
2302 2302
2303 2303 strcpy(saved_jvm_path, buf);
2304 2304 }
2305 2305
2306 2306 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2307 2307 // no prefix required, not even "_"
2308 2308 }
2309 2309
2310 2310 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2311 2311 // no suffix required
2312 2312 }
2313 2313
2314 2314 ////////////////////////////////////////////////////////////////////////////////
2315 2315 // sun.misc.Signal support
2316 2316
2317 2317 static volatile jint sigint_count = 0;
2318 2318
2319 2319 static void
2320 2320 UserHandler(int sig, void *siginfo, void *context) {
2321 2321 // 4511530 - sem_post is serialized and handled by the manager thread. When
2322 2322 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2323 2323 // don't want to flood the manager thread with sem_post requests.
2324 2324 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2325 2325 return;
2326 2326
2327 2327 // Ctrl-C is pressed during error reporting, likely because the error
2328 2328 // handler fails to abort. Let VM die immediately.
2329 2329 if (sig == SIGINT && is_error_reported()) {
2330 2330 os::die();
2331 2331 }
2332 2332
2333 2333 os::signal_notify(sig);
2334 2334 }
2335 2335
2336 2336 void* os::user_handler() {
2337 2337 return CAST_FROM_FN_PTR(void*, UserHandler);
2338 2338 }
2339 2339
2340 2340 extern "C" {
2341 2341 typedef void (*sa_handler_t)(int);
2342 2342 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2343 2343 }
2344 2344
2345 2345 void* os::signal(int signal_number, void* handler) {
2346 2346 struct sigaction sigAct, oldSigAct;
2347 2347
2348 2348 sigfillset(&(sigAct.sa_mask));
2349 2349 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2350 2350 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2351 2351
2352 2352 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2353 2353 // -1 means registration failed
2354 2354 return (void *)-1;
2355 2355 }
2356 2356
2357 2357 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2358 2358 }
2359 2359
2360 2360 void os::signal_raise(int signal_number) {
2361 2361 ::raise(signal_number);
2362 2362 }
2363 2363
2364 2364 /*
2365 2365 * The following code is moved from os.cpp for making this
2366 2366 * code platform specific, which it is by its very nature.
2367 2367 */
2368 2368
2369 2369 // Will be modified when max signal is changed to be dynamic
2370 2370 int os::sigexitnum_pd() {
2371 2371 return NSIG;
2372 2372 }
2373 2373
2374 2374 // a counter for each possible signal value
2375 2375 static volatile jint pending_signals[NSIG+1] = { 0 };
2376 2376
2377 2377 // Linux(POSIX) specific hand shaking semaphore.
2378 2378 static sem_t sig_sem;
2379 2379
2380 2380 void os::signal_init_pd() {
2381 2381 // Initialize signal structures
2382 2382 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2383 2383
2384 2384 // Initialize signal semaphore
2385 2385 ::sem_init(&sig_sem, 0, 0);
2386 2386 }
2387 2387
2388 2388 void os::signal_notify(int sig) {
2389 2389 Atomic::inc(&pending_signals[sig]);
2390 2390 ::sem_post(&sig_sem);
2391 2391 }
2392 2392
2393 2393 static int check_pending_signals(bool wait) {
2394 2394 Atomic::store(0, &sigint_count);
2395 2395 for (;;) {
2396 2396 for (int i = 0; i < NSIG + 1; i++) {
2397 2397 jint n = pending_signals[i];
2398 2398 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2399 2399 return i;
2400 2400 }
2401 2401 }
2402 2402 if (!wait) {
2403 2403 return -1;
2404 2404 }
2405 2405 JavaThread *thread = JavaThread::current();
2406 2406 ThreadBlockInVM tbivm(thread);
2407 2407
2408 2408 bool threadIsSuspended;
2409 2409 do {
2410 2410 thread->set_suspend_equivalent();
2411 2411 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2412 2412 ::sem_wait(&sig_sem);
2413 2413
2414 2414 // were we externally suspended while we were waiting?
2415 2415 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2416 2416 if (threadIsSuspended) {
2417 2417 //
2418 2418 // The semaphore has been incremented, but while we were waiting
2419 2419 // another thread suspended us. We don't want to continue running
2420 2420 // while suspended because that would surprise the thread that
2421 2421 // suspended us.
2422 2422 //
2423 2423 ::sem_post(&sig_sem);
2424 2424
2425 2425 thread->java_suspend_self();
2426 2426 }
2427 2427 } while (threadIsSuspended);
2428 2428 }
2429 2429 }
2430 2430
2431 2431 int os::signal_lookup() {
2432 2432 return check_pending_signals(false);
2433 2433 }
2434 2434
2435 2435 int os::signal_wait() {
2436 2436 return check_pending_signals(true);
2437 2437 }
2438 2438
2439 2439 ////////////////////////////////////////////////////////////////////////////////
2440 2440 // Virtual Memory
2441 2441
2442 2442 int os::vm_page_size() {
2443 2443 // Seems redundant as all get out
2444 2444 assert(os::Linux::page_size() != -1, "must call os::init");
2445 2445 return os::Linux::page_size();
2446 2446 }
2447 2447
2448 2448 // Solaris allocates memory by pages.
2449 2449 int os::vm_allocation_granularity() {
2450 2450 assert(os::Linux::page_size() != -1, "must call os::init");
2451 2451 return os::Linux::page_size();
2452 2452 }
2453 2453
2454 2454 // Rationale behind this function:
2455 2455 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2456 2456 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2457 2457 // samples for JITted code. Here we create private executable mapping over the code cache
2458 2458 // and then we can use standard (well, almost, as mapping can change) way to provide
2459 2459 // info for the reporting script by storing timestamp and location of symbol
2460 2460 void linux_wrap_code(char* base, size_t size) {
2461 2461 static volatile jint cnt = 0;
2462 2462
2463 2463 if (!UseOprofile) {
2464 2464 return;
2465 2465 }
2466 2466
2467 2467 char buf[PATH_MAX+1];
2468 2468 int num = Atomic::add(1, &cnt);
2469 2469
2470 2470 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2471 2471 os::get_temp_directory(), os::current_process_id(), num);
2472 2472 unlink(buf);
2473 2473
2474 2474 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2475 2475
2476 2476 if (fd != -1) {
2477 2477 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2478 2478 if (rv != (off_t)-1) {
2479 2479 if (::write(fd, "", 1) == 1) {
2480 2480 mmap(base, size,
2481 2481 PROT_READ|PROT_WRITE|PROT_EXEC,
2482 2482 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2483 2483 }
2484 2484 }
2485 2485 ::close(fd);
2486 2486 unlink(buf);
2487 2487 }
2488 2488 }
2489 2489
2490 2490 // NOTE: Linux kernel does not really reserve the pages for us.
2491 2491 // All it does is to check if there are enough free pages
2492 2492 // left at the time of mmap(). This could be a potential
2493 2493 // problem.
2494 2494 bool os::commit_memory(char* addr, size_t size, bool exec) {
2495 2495 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2496 2496 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2497 2497 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2498 2498 if (res != (uintptr_t) MAP_FAILED) {
2499 2499 if (UseNUMAInterleaving) {
2500 2500 numa_make_global(addr, size);
2501 2501 }
2502 2502 return true;
2503 2503 }
2504 2504 return false;
2505 2505 }
2506 2506
2507 2507 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2508 2508 #ifndef MAP_HUGETLB
2509 2509 #define MAP_HUGETLB 0x40000
2510 2510 #endif
2511 2511
2512 2512 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2513 2513 #ifndef MADV_HUGEPAGE
2514 2514 #define MADV_HUGEPAGE 14
2515 2515 #endif
2516 2516
2517 2517 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2518 2518 bool exec) {
2519 2519 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2520 2520 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2521 2521 uintptr_t res =
2522 2522 (uintptr_t) ::mmap(addr, size, prot,
2523 2523 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2524 2524 -1, 0);
2525 2525 if (res != (uintptr_t) MAP_FAILED) {
2526 2526 if (UseNUMAInterleaving) {
2527 2527 numa_make_global(addr, size);
2528 2528 }
2529 2529 return true;
2530 2530 }
2531 2531 // Fall through and try to use small pages
2532 2532 }
2533 2533
2534 2534 if (commit_memory(addr, size, exec)) {
2535 2535 realign_memory(addr, size, alignment_hint);
2536 2536 return true;
2537 2537 }
2538 2538 return false;
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2539 2539 }
2540 2540
2541 2541 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2542 2542 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2543 2543 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2544 2544 // be supported or the memory may already be backed by huge pages.
2545 2545 ::madvise(addr, bytes, MADV_HUGEPAGE);
2546 2546 }
2547 2547 }
2548 2548
2549 -void os::free_memory(char *addr, size_t bytes) {
2550 - commit_memory(addr, bytes, false);
2549 +void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2550 + commit_memory(addr, bytes, alignment_hint, false);
2551 2551 }
2552 2552
2553 2553 void os::numa_make_global(char *addr, size_t bytes) {
2554 2554 Linux::numa_interleave_memory(addr, bytes);
2555 2555 }
2556 2556
2557 2557 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2558 2558 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2559 2559 }
2560 2560
2561 2561 bool os::numa_topology_changed() { return false; }
2562 2562
2563 2563 size_t os::numa_get_groups_num() {
2564 2564 int max_node = Linux::numa_max_node();
2565 2565 return max_node > 0 ? max_node + 1 : 1;
2566 2566 }
2567 2567
2568 2568 int os::numa_get_group_id() {
2569 2569 int cpu_id = Linux::sched_getcpu();
2570 2570 if (cpu_id != -1) {
2571 2571 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2572 2572 if (lgrp_id != -1) {
2573 2573 return lgrp_id;
2574 2574 }
2575 2575 }
2576 2576 return 0;
2577 2577 }
2578 2578
2579 2579 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2580 2580 for (size_t i = 0; i < size; i++) {
2581 2581 ids[i] = i;
2582 2582 }
2583 2583 return size;
2584 2584 }
2585 2585
2586 2586 bool os::get_page_info(char *start, page_info* info) {
2587 2587 return false;
2588 2588 }
2589 2589
2590 2590 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2591 2591 return end;
2592 2592 }
2593 2593
2594 2594
2595 2595 int os::Linux::sched_getcpu_syscall(void) {
2596 2596 unsigned int cpu;
2597 2597 int retval = -1;
2598 2598
2599 2599 #if defined(IA32)
2600 2600 # ifndef SYS_getcpu
2601 2601 # define SYS_getcpu 318
2602 2602 # endif
2603 2603 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2604 2604 #elif defined(AMD64)
2605 2605 // Unfortunately we have to bring all these macros here from vsyscall.h
2606 2606 // to be able to compile on old linuxes.
2607 2607 # define __NR_vgetcpu 2
2608 2608 # define VSYSCALL_START (-10UL << 20)
2609 2609 # define VSYSCALL_SIZE 1024
2610 2610 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2611 2611 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2612 2612 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2613 2613 retval = vgetcpu(&cpu, NULL, NULL);
2614 2614 #endif
2615 2615
2616 2616 return (retval == -1) ? retval : cpu;
2617 2617 }
2618 2618
2619 2619 // Something to do with the numa-aware allocator needs these symbols
2620 2620 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2621 2621 extern "C" JNIEXPORT void numa_error(char *where) { }
2622 2622 extern "C" JNIEXPORT int fork1() { return fork(); }
2623 2623
2624 2624
2625 2625 // If we are running with libnuma version > 2, then we should
2626 2626 // be trying to use symbols with versions 1.1
2627 2627 // If we are running with earlier version, which did not have symbol versions,
2628 2628 // we should use the base version.
2629 2629 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2630 2630 void *f = dlvsym(handle, name, "libnuma_1.1");
2631 2631 if (f == NULL) {
2632 2632 f = dlsym(handle, name);
2633 2633 }
2634 2634 return f;
2635 2635 }
2636 2636
2637 2637 bool os::Linux::libnuma_init() {
2638 2638 // sched_getcpu() should be in libc.
2639 2639 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2640 2640 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2641 2641
2642 2642 // If it's not, try a direct syscall.
2643 2643 if (sched_getcpu() == -1)
2644 2644 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2645 2645
2646 2646 if (sched_getcpu() != -1) { // Does it work?
2647 2647 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2648 2648 if (handle != NULL) {
2649 2649 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2650 2650 libnuma_dlsym(handle, "numa_node_to_cpus")));
2651 2651 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2652 2652 libnuma_dlsym(handle, "numa_max_node")));
2653 2653 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2654 2654 libnuma_dlsym(handle, "numa_available")));
2655 2655 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2656 2656 libnuma_dlsym(handle, "numa_tonode_memory")));
2657 2657 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2658 2658 libnuma_dlsym(handle, "numa_interleave_memory")));
2659 2659
2660 2660
2661 2661 if (numa_available() != -1) {
2662 2662 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2663 2663 // Create a cpu -> node mapping
2664 2664 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2665 2665 rebuild_cpu_to_node_map();
2666 2666 return true;
2667 2667 }
2668 2668 }
2669 2669 }
2670 2670 return false;
2671 2671 }
2672 2672
2673 2673 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2674 2674 // The table is later used in get_node_by_cpu().
2675 2675 void os::Linux::rebuild_cpu_to_node_map() {
2676 2676 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2677 2677 // in libnuma (possible values are starting from 16,
2678 2678 // and continuing up with every other power of 2, but less
2679 2679 // than the maximum number of CPUs supported by kernel), and
2680 2680 // is a subject to change (in libnuma version 2 the requirements
2681 2681 // are more reasonable) we'll just hardcode the number they use
2682 2682 // in the library.
2683 2683 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2684 2684
2685 2685 size_t cpu_num = os::active_processor_count();
2686 2686 size_t cpu_map_size = NCPUS / BitsPerCLong;
2687 2687 size_t cpu_map_valid_size =
2688 2688 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2689 2689
2690 2690 cpu_to_node()->clear();
2691 2691 cpu_to_node()->at_grow(cpu_num - 1);
2692 2692 size_t node_num = numa_get_groups_num();
2693 2693
2694 2694 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2695 2695 for (size_t i = 0; i < node_num; i++) {
2696 2696 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2697 2697 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2698 2698 if (cpu_map[j] != 0) {
2699 2699 for (size_t k = 0; k < BitsPerCLong; k++) {
2700 2700 if (cpu_map[j] & (1UL << k)) {
2701 2701 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2702 2702 }
2703 2703 }
2704 2704 }
2705 2705 }
2706 2706 }
2707 2707 }
2708 2708 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2709 2709 }
2710 2710
2711 2711 int os::Linux::get_node_by_cpu(int cpu_id) {
2712 2712 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2713 2713 return cpu_to_node()->at(cpu_id);
2714 2714 }
2715 2715 return -1;
2716 2716 }
2717 2717
2718 2718 GrowableArray<int>* os::Linux::_cpu_to_node;
2719 2719 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2720 2720 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2721 2721 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2722 2722 os::Linux::numa_available_func_t os::Linux::_numa_available;
2723 2723 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2724 2724 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2725 2725 unsigned long* os::Linux::_numa_all_nodes;
2726 2726
2727 2727 bool os::uncommit_memory(char* addr, size_t size) {
2728 2728 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2729 2729 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2730 2730 return res != (uintptr_t) MAP_FAILED;
2731 2731 }
2732 2732
2733 2733 // Linux uses a growable mapping for the stack, and if the mapping for
2734 2734 // the stack guard pages is not removed when we detach a thread the
2735 2735 // stack cannot grow beyond the pages where the stack guard was
2736 2736 // mapped. If at some point later in the process the stack expands to
2737 2737 // that point, the Linux kernel cannot expand the stack any further
2738 2738 // because the guard pages are in the way, and a segfault occurs.
2739 2739 //
2740 2740 // However, it's essential not to split the stack region by unmapping
2741 2741 // a region (leaving a hole) that's already part of the stack mapping,
2742 2742 // so if the stack mapping has already grown beyond the guard pages at
2743 2743 // the time we create them, we have to truncate the stack mapping.
2744 2744 // So, we need to know the extent of the stack mapping when
2745 2745 // create_stack_guard_pages() is called.
2746 2746
2747 2747 // Find the bounds of the stack mapping. Return true for success.
2748 2748 //
2749 2749 // We only need this for stacks that are growable: at the time of
2750 2750 // writing thread stacks don't use growable mappings (i.e. those
2751 2751 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2752 2752 // only applies to the main thread.
2753 2753
2754 2754 static
2755 2755 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2756 2756
2757 2757 char buf[128];
2758 2758 int fd, sz;
2759 2759
2760 2760 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2761 2761 return false;
2762 2762 }
2763 2763
2764 2764 const char kw[] = "[stack]";
2765 2765 const int kwlen = sizeof(kw)-1;
2766 2766
2767 2767 // Address part of /proc/self/maps couldn't be more than 128 bytes
2768 2768 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2769 2769 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2770 2770 // Extract addresses
2771 2771 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2772 2772 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2773 2773 if (sp >= *bottom && sp <= *top) {
2774 2774 ::close(fd);
2775 2775 return true;
2776 2776 }
2777 2777 }
2778 2778 }
2779 2779 }
2780 2780
2781 2781 ::close(fd);
2782 2782 return false;
2783 2783 }
2784 2784
2785 2785
2786 2786 // If the (growable) stack mapping already extends beyond the point
2787 2787 // where we're going to put our guard pages, truncate the mapping at
2788 2788 // that point by munmap()ping it. This ensures that when we later
2789 2789 // munmap() the guard pages we don't leave a hole in the stack
2790 2790 // mapping. This only affects the main/initial thread, but guard
2791 2791 // against future OS changes
2792 2792 bool os::create_stack_guard_pages(char* addr, size_t size) {
2793 2793 uintptr_t stack_extent, stack_base;
2794 2794 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2795 2795 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2796 2796 assert(os::Linux::is_initial_thread(),
2797 2797 "growable stack in non-initial thread");
2798 2798 if (stack_extent < (uintptr_t)addr)
2799 2799 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2800 2800 }
2801 2801
2802 2802 return os::commit_memory(addr, size);
2803 2803 }
2804 2804
2805 2805 // If this is a growable mapping, remove the guard pages entirely by
2806 2806 // munmap()ping them. If not, just call uncommit_memory(). This only
2807 2807 // affects the main/initial thread, but guard against future OS changes
2808 2808 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2809 2809 uintptr_t stack_extent, stack_base;
2810 2810 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2811 2811 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2812 2812 assert(os::Linux::is_initial_thread(),
2813 2813 "growable stack in non-initial thread");
2814 2814
2815 2815 return ::munmap(addr, size) == 0;
2816 2816 }
2817 2817
2818 2818 return os::uncommit_memory(addr, size);
2819 2819 }
2820 2820
2821 2821 static address _highest_vm_reserved_address = NULL;
2822 2822
2823 2823 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2824 2824 // at 'requested_addr'. If there are existing memory mappings at the same
2825 2825 // location, however, they will be overwritten. If 'fixed' is false,
2826 2826 // 'requested_addr' is only treated as a hint, the return value may or
2827 2827 // may not start from the requested address. Unlike Linux mmap(), this
2828 2828 // function returns NULL to indicate failure.
2829 2829 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2830 2830 char * addr;
2831 2831 int flags;
2832 2832
2833 2833 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2834 2834 if (fixed) {
2835 2835 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2836 2836 flags |= MAP_FIXED;
2837 2837 }
2838 2838
2839 2839 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2840 2840 // to PROT_EXEC if executable when we commit the page.
2841 2841 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2842 2842 flags, -1, 0);
2843 2843
2844 2844 if (addr != MAP_FAILED) {
2845 2845 // anon_mmap() should only get called during VM initialization,
2846 2846 // don't need lock (actually we can skip locking even it can be called
2847 2847 // from multiple threads, because _highest_vm_reserved_address is just a
2848 2848 // hint about the upper limit of non-stack memory regions.)
2849 2849 if ((address)addr + bytes > _highest_vm_reserved_address) {
2850 2850 _highest_vm_reserved_address = (address)addr + bytes;
2851 2851 }
2852 2852 }
2853 2853
2854 2854 return addr == MAP_FAILED ? NULL : addr;
2855 2855 }
2856 2856
2857 2857 // Don't update _highest_vm_reserved_address, because there might be memory
2858 2858 // regions above addr + size. If so, releasing a memory region only creates
2859 2859 // a hole in the address space, it doesn't help prevent heap-stack collision.
2860 2860 //
2861 2861 static int anon_munmap(char * addr, size_t size) {
2862 2862 return ::munmap(addr, size) == 0;
2863 2863 }
2864 2864
2865 2865 char* os::reserve_memory(size_t bytes, char* requested_addr,
2866 2866 size_t alignment_hint) {
2867 2867 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2868 2868 }
2869 2869
2870 2870 bool os::release_memory(char* addr, size_t size) {
2871 2871 return anon_munmap(addr, size);
2872 2872 }
2873 2873
2874 2874 static address highest_vm_reserved_address() {
2875 2875 return _highest_vm_reserved_address;
2876 2876 }
2877 2877
2878 2878 static bool linux_mprotect(char* addr, size_t size, int prot) {
2879 2879 // Linux wants the mprotect address argument to be page aligned.
2880 2880 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2881 2881
2882 2882 // According to SUSv3, mprotect() should only be used with mappings
2883 2883 // established by mmap(), and mmap() always maps whole pages. Unaligned
2884 2884 // 'addr' likely indicates problem in the VM (e.g. trying to change
2885 2885 // protection of malloc'ed or statically allocated memory). Check the
2886 2886 // caller if you hit this assert.
2887 2887 assert(addr == bottom, "sanity check");
2888 2888
2889 2889 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2890 2890 return ::mprotect(bottom, size, prot) == 0;
2891 2891 }
2892 2892
2893 2893 // Set protections specified
2894 2894 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2895 2895 bool is_committed) {
2896 2896 unsigned int p = 0;
2897 2897 switch (prot) {
2898 2898 case MEM_PROT_NONE: p = PROT_NONE; break;
2899 2899 case MEM_PROT_READ: p = PROT_READ; break;
2900 2900 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2901 2901 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2902 2902 default:
2903 2903 ShouldNotReachHere();
2904 2904 }
2905 2905 // is_committed is unused.
2906 2906 return linux_mprotect(addr, bytes, p);
2907 2907 }
2908 2908
2909 2909 bool os::guard_memory(char* addr, size_t size) {
2910 2910 return linux_mprotect(addr, size, PROT_NONE);
2911 2911 }
2912 2912
2913 2913 bool os::unguard_memory(char* addr, size_t size) {
2914 2914 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2915 2915 }
2916 2916
2917 2917 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2918 2918 bool result = false;
2919 2919 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2920 2920 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2921 2921 -1, 0);
2922 2922
2923 2923 if (p != (void *) -1) {
2924 2924 // We don't know if this really is a huge page or not.
2925 2925 FILE *fp = fopen("/proc/self/maps", "r");
2926 2926 if (fp) {
2927 2927 while (!feof(fp)) {
2928 2928 char chars[257];
2929 2929 long x = 0;
2930 2930 if (fgets(chars, sizeof(chars), fp)) {
2931 2931 if (sscanf(chars, "%lx-%*x", &x) == 1
2932 2932 && x == (long)p) {
2933 2933 if (strstr (chars, "hugepage")) {
2934 2934 result = true;
2935 2935 break;
2936 2936 }
2937 2937 }
2938 2938 }
2939 2939 }
2940 2940 fclose(fp);
2941 2941 }
2942 2942 munmap (p, page_size);
2943 2943 if (result)
2944 2944 return true;
2945 2945 }
2946 2946
2947 2947 if (warn) {
2948 2948 warning("HugeTLBFS is not supported by the operating system.");
2949 2949 }
2950 2950
2951 2951 return result;
2952 2952 }
2953 2953
2954 2954 /*
2955 2955 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2956 2956 *
2957 2957 * From the coredump_filter documentation:
2958 2958 *
2959 2959 * - (bit 0) anonymous private memory
2960 2960 * - (bit 1) anonymous shared memory
2961 2961 * - (bit 2) file-backed private memory
2962 2962 * - (bit 3) file-backed shared memory
2963 2963 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2964 2964 * effective only if the bit 2 is cleared)
2965 2965 * - (bit 5) hugetlb private memory
2966 2966 * - (bit 6) hugetlb shared memory
2967 2967 */
2968 2968 static void set_coredump_filter(void) {
2969 2969 FILE *f;
2970 2970 long cdm;
2971 2971
2972 2972 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2973 2973 return;
2974 2974 }
2975 2975
2976 2976 if (fscanf(f, "%lx", &cdm) != 1) {
2977 2977 fclose(f);
2978 2978 return;
2979 2979 }
2980 2980
2981 2981 rewind(f);
2982 2982
2983 2983 if ((cdm & LARGEPAGES_BIT) == 0) {
2984 2984 cdm |= LARGEPAGES_BIT;
2985 2985 fprintf(f, "%#lx", cdm);
2986 2986 }
2987 2987
2988 2988 fclose(f);
2989 2989 }
2990 2990
2991 2991 // Large page support
2992 2992
2993 2993 static size_t _large_page_size = 0;
2994 2994
2995 2995 void os::large_page_init() {
2996 2996 if (!UseLargePages) {
2997 2997 UseHugeTLBFS = false;
2998 2998 UseSHM = false;
2999 2999 return;
3000 3000 }
3001 3001
3002 3002 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
3003 3003 // If UseLargePages is specified on the command line try both methods,
3004 3004 // if it's default, then try only HugeTLBFS.
3005 3005 if (FLAG_IS_DEFAULT(UseLargePages)) {
3006 3006 UseHugeTLBFS = true;
3007 3007 } else {
3008 3008 UseHugeTLBFS = UseSHM = true;
3009 3009 }
3010 3010 }
3011 3011
3012 3012 if (LargePageSizeInBytes) {
3013 3013 _large_page_size = LargePageSizeInBytes;
3014 3014 } else {
3015 3015 // large_page_size on Linux is used to round up heap size. x86 uses either
3016 3016 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3017 3017 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3018 3018 // page as large as 256M.
3019 3019 //
3020 3020 // Here we try to figure out page size by parsing /proc/meminfo and looking
3021 3021 // for a line with the following format:
3022 3022 // Hugepagesize: 2048 kB
3023 3023 //
3024 3024 // If we can't determine the value (e.g. /proc is not mounted, or the text
3025 3025 // format has been changed), we'll use the largest page size supported by
3026 3026 // the processor.
3027 3027
3028 3028 #ifndef ZERO
3029 3029 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3030 3030 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3031 3031 #endif // ZERO
3032 3032
3033 3033 FILE *fp = fopen("/proc/meminfo", "r");
3034 3034 if (fp) {
3035 3035 while (!feof(fp)) {
3036 3036 int x = 0;
3037 3037 char buf[16];
3038 3038 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3039 3039 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3040 3040 _large_page_size = x * K;
3041 3041 break;
3042 3042 }
3043 3043 } else {
3044 3044 // skip to next line
3045 3045 for (;;) {
3046 3046 int ch = fgetc(fp);
3047 3047 if (ch == EOF || ch == (int)'\n') break;
3048 3048 }
3049 3049 }
3050 3050 }
3051 3051 fclose(fp);
3052 3052 }
3053 3053 }
3054 3054
3055 3055 // print a warning if any large page related flag is specified on command line
3056 3056 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3057 3057
3058 3058 const size_t default_page_size = (size_t)Linux::page_size();
3059 3059 if (_large_page_size > default_page_size) {
3060 3060 _page_sizes[0] = _large_page_size;
3061 3061 _page_sizes[1] = default_page_size;
3062 3062 _page_sizes[2] = 0;
3063 3063 }
3064 3064 UseHugeTLBFS = UseHugeTLBFS &&
3065 3065 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3066 3066
3067 3067 if (UseHugeTLBFS)
3068 3068 UseSHM = false;
3069 3069
3070 3070 UseLargePages = UseHugeTLBFS || UseSHM;
3071 3071
3072 3072 set_coredump_filter();
3073 3073 }
3074 3074
3075 3075 #ifndef SHM_HUGETLB
3076 3076 #define SHM_HUGETLB 04000
3077 3077 #endif
3078 3078
3079 3079 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3080 3080 // "exec" is passed in but not used. Creating the shared image for
3081 3081 // the code cache doesn't have an SHM_X executable permission to check.
3082 3082 assert(UseLargePages && UseSHM, "only for SHM large pages");
3083 3083
3084 3084 key_t key = IPC_PRIVATE;
3085 3085 char *addr;
3086 3086
3087 3087 bool warn_on_failure = UseLargePages &&
3088 3088 (!FLAG_IS_DEFAULT(UseLargePages) ||
3089 3089 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3090 3090 );
3091 3091 char msg[128];
3092 3092
3093 3093 // Create a large shared memory region to attach to based on size.
3094 3094 // Currently, size is the total size of the heap
3095 3095 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3096 3096 if (shmid == -1) {
3097 3097 // Possible reasons for shmget failure:
3098 3098 // 1. shmmax is too small for Java heap.
3099 3099 // > check shmmax value: cat /proc/sys/kernel/shmmax
3100 3100 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3101 3101 // 2. not enough large page memory.
3102 3102 // > check available large pages: cat /proc/meminfo
3103 3103 // > increase amount of large pages:
3104 3104 // echo new_value > /proc/sys/vm/nr_hugepages
3105 3105 // Note 1: different Linux may use different name for this property,
3106 3106 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3107 3107 // Note 2: it's possible there's enough physical memory available but
3108 3108 // they are so fragmented after a long run that they can't
3109 3109 // coalesce into large pages. Try to reserve large pages when
3110 3110 // the system is still "fresh".
3111 3111 if (warn_on_failure) {
3112 3112 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3113 3113 warning(msg);
3114 3114 }
3115 3115 return NULL;
3116 3116 }
3117 3117
3118 3118 // attach to the region
3119 3119 addr = (char*)shmat(shmid, req_addr, 0);
3120 3120 int err = errno;
3121 3121
3122 3122 // Remove shmid. If shmat() is successful, the actual shared memory segment
3123 3123 // will be deleted when it's detached by shmdt() or when the process
3124 3124 // terminates. If shmat() is not successful this will remove the shared
3125 3125 // segment immediately.
3126 3126 shmctl(shmid, IPC_RMID, NULL);
3127 3127
3128 3128 if ((intptr_t)addr == -1) {
3129 3129 if (warn_on_failure) {
3130 3130 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3131 3131 warning(msg);
3132 3132 }
3133 3133 return NULL;
3134 3134 }
3135 3135
3136 3136 if ((addr != NULL) && UseNUMAInterleaving) {
3137 3137 numa_make_global(addr, bytes);
3138 3138 }
3139 3139
3140 3140 return addr;
3141 3141 }
3142 3142
3143 3143 bool os::release_memory_special(char* base, size_t bytes) {
3144 3144 // detaching the SHM segment will also delete it, see reserve_memory_special()
3145 3145 int rslt = shmdt(base);
3146 3146 return rslt == 0;
3147 3147 }
3148 3148
3149 3149 size_t os::large_page_size() {
3150 3150 return _large_page_size;
3151 3151 }
3152 3152
3153 3153 // HugeTLBFS allows application to commit large page memory on demand;
3154 3154 // with SysV SHM the entire memory region must be allocated as shared
3155 3155 // memory.
3156 3156 bool os::can_commit_large_page_memory() {
3157 3157 return UseHugeTLBFS;
3158 3158 }
3159 3159
3160 3160 bool os::can_execute_large_page_memory() {
3161 3161 return UseHugeTLBFS;
3162 3162 }
3163 3163
3164 3164 // Reserve memory at an arbitrary address, only if that area is
3165 3165 // available (and not reserved for something else).
3166 3166
3167 3167 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3168 3168 const int max_tries = 10;
3169 3169 char* base[max_tries];
3170 3170 size_t size[max_tries];
3171 3171 const size_t gap = 0x000000;
3172 3172
3173 3173 // Assert only that the size is a multiple of the page size, since
3174 3174 // that's all that mmap requires, and since that's all we really know
3175 3175 // about at this low abstraction level. If we need higher alignment,
3176 3176 // we can either pass an alignment to this method or verify alignment
3177 3177 // in one of the methods further up the call chain. See bug 5044738.
3178 3178 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3179 3179
3180 3180 // Repeatedly allocate blocks until the block is allocated at the
3181 3181 // right spot. Give up after max_tries. Note that reserve_memory() will
3182 3182 // automatically update _highest_vm_reserved_address if the call is
3183 3183 // successful. The variable tracks the highest memory address every reserved
3184 3184 // by JVM. It is used to detect heap-stack collision if running with
3185 3185 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3186 3186 // space than needed, it could confuse the collision detecting code. To
3187 3187 // solve the problem, save current _highest_vm_reserved_address and
3188 3188 // calculate the correct value before return.
3189 3189 address old_highest = _highest_vm_reserved_address;
3190 3190
3191 3191 // Linux mmap allows caller to pass an address as hint; give it a try first,
3192 3192 // if kernel honors the hint then we can return immediately.
3193 3193 char * addr = anon_mmap(requested_addr, bytes, false);
3194 3194 if (addr == requested_addr) {
3195 3195 return requested_addr;
3196 3196 }
3197 3197
3198 3198 if (addr != NULL) {
3199 3199 // mmap() is successful but it fails to reserve at the requested address
3200 3200 anon_munmap(addr, bytes);
3201 3201 }
3202 3202
3203 3203 int i;
3204 3204 for (i = 0; i < max_tries; ++i) {
3205 3205 base[i] = reserve_memory(bytes);
3206 3206
3207 3207 if (base[i] != NULL) {
3208 3208 // Is this the block we wanted?
3209 3209 if (base[i] == requested_addr) {
3210 3210 size[i] = bytes;
3211 3211 break;
3212 3212 }
3213 3213
3214 3214 // Does this overlap the block we wanted? Give back the overlapped
3215 3215 // parts and try again.
3216 3216
3217 3217 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3218 3218 if (top_overlap >= 0 && top_overlap < bytes) {
3219 3219 unmap_memory(base[i], top_overlap);
3220 3220 base[i] += top_overlap;
3221 3221 size[i] = bytes - top_overlap;
3222 3222 } else {
3223 3223 size_t bottom_overlap = base[i] + bytes - requested_addr;
3224 3224 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3225 3225 unmap_memory(requested_addr, bottom_overlap);
3226 3226 size[i] = bytes - bottom_overlap;
3227 3227 } else {
3228 3228 size[i] = bytes;
3229 3229 }
3230 3230 }
3231 3231 }
3232 3232 }
3233 3233
3234 3234 // Give back the unused reserved pieces.
3235 3235
3236 3236 for (int j = 0; j < i; ++j) {
3237 3237 if (base[j] != NULL) {
3238 3238 unmap_memory(base[j], size[j]);
3239 3239 }
3240 3240 }
3241 3241
3242 3242 if (i < max_tries) {
3243 3243 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3244 3244 return requested_addr;
3245 3245 } else {
3246 3246 _highest_vm_reserved_address = old_highest;
3247 3247 return NULL;
3248 3248 }
3249 3249 }
3250 3250
3251 3251 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3252 3252 return ::read(fd, buf, nBytes);
3253 3253 }
3254 3254
3255 3255 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3256 3256 // Solaris uses poll(), linux uses park().
3257 3257 // Poll() is likely a better choice, assuming that Thread.interrupt()
3258 3258 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3259 3259 // SIGSEGV, see 4355769.
3260 3260
3261 3261 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3262 3262 assert(thread == Thread::current(), "thread consistency check");
3263 3263
3264 3264 ParkEvent * const slp = thread->_SleepEvent ;
3265 3265 slp->reset() ;
3266 3266 OrderAccess::fence() ;
3267 3267
3268 3268 if (interruptible) {
3269 3269 jlong prevtime = javaTimeNanos();
3270 3270
3271 3271 for (;;) {
3272 3272 if (os::is_interrupted(thread, true)) {
3273 3273 return OS_INTRPT;
3274 3274 }
3275 3275
3276 3276 jlong newtime = javaTimeNanos();
3277 3277
3278 3278 if (newtime - prevtime < 0) {
3279 3279 // time moving backwards, should only happen if no monotonic clock
3280 3280 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3281 3281 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3282 3282 } else {
3283 3283 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3284 3284 }
3285 3285
3286 3286 if(millis <= 0) {
3287 3287 return OS_OK;
3288 3288 }
3289 3289
3290 3290 prevtime = newtime;
3291 3291
3292 3292 {
3293 3293 assert(thread->is_Java_thread(), "sanity check");
3294 3294 JavaThread *jt = (JavaThread *) thread;
3295 3295 ThreadBlockInVM tbivm(jt);
3296 3296 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3297 3297
3298 3298 jt->set_suspend_equivalent();
3299 3299 // cleared by handle_special_suspend_equivalent_condition() or
3300 3300 // java_suspend_self() via check_and_wait_while_suspended()
3301 3301
3302 3302 slp->park(millis);
3303 3303
3304 3304 // were we externally suspended while we were waiting?
3305 3305 jt->check_and_wait_while_suspended();
3306 3306 }
3307 3307 }
3308 3308 } else {
3309 3309 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3310 3310 jlong prevtime = javaTimeNanos();
3311 3311
3312 3312 for (;;) {
3313 3313 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3314 3314 // the 1st iteration ...
3315 3315 jlong newtime = javaTimeNanos();
3316 3316
3317 3317 if (newtime - prevtime < 0) {
3318 3318 // time moving backwards, should only happen if no monotonic clock
3319 3319 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3320 3320 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3321 3321 } else {
3322 3322 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3323 3323 }
3324 3324
3325 3325 if(millis <= 0) break ;
3326 3326
3327 3327 prevtime = newtime;
3328 3328 slp->park(millis);
3329 3329 }
3330 3330 return OS_OK ;
3331 3331 }
3332 3332 }
3333 3333
3334 3334 int os::naked_sleep() {
3335 3335 // %% make the sleep time an integer flag. for now use 1 millisec.
3336 3336 return os::sleep(Thread::current(), 1, false);
3337 3337 }
3338 3338
3339 3339 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3340 3340 void os::infinite_sleep() {
3341 3341 while (true) { // sleep forever ...
3342 3342 ::sleep(100); // ... 100 seconds at a time
3343 3343 }
3344 3344 }
3345 3345
3346 3346 // Used to convert frequent JVM_Yield() to nops
3347 3347 bool os::dont_yield() {
3348 3348 return DontYieldALot;
3349 3349 }
3350 3350
3351 3351 void os::yield() {
3352 3352 sched_yield();
3353 3353 }
3354 3354
3355 3355 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3356 3356
3357 3357 void os::yield_all(int attempts) {
3358 3358 // Yields to all threads, including threads with lower priorities
3359 3359 // Threads on Linux are all with same priority. The Solaris style
3360 3360 // os::yield_all() with nanosleep(1ms) is not necessary.
3361 3361 sched_yield();
3362 3362 }
3363 3363
3364 3364 // Called from the tight loops to possibly influence time-sharing heuristics
3365 3365 void os::loop_breaker(int attempts) {
3366 3366 os::yield_all(attempts);
3367 3367 }
3368 3368
3369 3369 ////////////////////////////////////////////////////////////////////////////////
3370 3370 // thread priority support
3371 3371
3372 3372 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3373 3373 // only supports dynamic priority, static priority must be zero. For real-time
3374 3374 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3375 3375 // However, for large multi-threaded applications, SCHED_RR is not only slower
3376 3376 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3377 3377 // of 5 runs - Sep 2005).
3378 3378 //
3379 3379 // The following code actually changes the niceness of kernel-thread/LWP. It
3380 3380 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3381 3381 // not the entire user process, and user level threads are 1:1 mapped to kernel
3382 3382 // threads. It has always been the case, but could change in the future. For
3383 3383 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3384 3384 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3385 3385
3386 3386 int os::java_to_os_priority[MaxPriority + 1] = {
3387 3387 19, // 0 Entry should never be used
3388 3388
3389 3389 4, // 1 MinPriority
3390 3390 3, // 2
3391 3391 2, // 3
3392 3392
3393 3393 1, // 4
3394 3394 0, // 5 NormPriority
3395 3395 -1, // 6
3396 3396
3397 3397 -2, // 7
3398 3398 -3, // 8
3399 3399 -4, // 9 NearMaxPriority
3400 3400
3401 3401 -5 // 10 MaxPriority
3402 3402 };
3403 3403
3404 3404 static int prio_init() {
3405 3405 if (ThreadPriorityPolicy == 1) {
3406 3406 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3407 3407 // if effective uid is not root. Perhaps, a more elegant way of doing
3408 3408 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3409 3409 if (geteuid() != 0) {
3410 3410 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3411 3411 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3412 3412 }
3413 3413 ThreadPriorityPolicy = 0;
3414 3414 }
3415 3415 }
3416 3416 return 0;
3417 3417 }
3418 3418
3419 3419 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3420 3420 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3421 3421
3422 3422 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3423 3423 return (ret == 0) ? OS_OK : OS_ERR;
3424 3424 }
3425 3425
3426 3426 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3427 3427 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3428 3428 *priority_ptr = java_to_os_priority[NormPriority];
3429 3429 return OS_OK;
3430 3430 }
3431 3431
3432 3432 errno = 0;
3433 3433 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3434 3434 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3435 3435 }
3436 3436
3437 3437 // Hint to the underlying OS that a task switch would not be good.
3438 3438 // Void return because it's a hint and can fail.
3439 3439 void os::hint_no_preempt() {}
3440 3440
3441 3441 ////////////////////////////////////////////////////////////////////////////////
3442 3442 // suspend/resume support
3443 3443
3444 3444 // the low-level signal-based suspend/resume support is a remnant from the
3445 3445 // old VM-suspension that used to be for java-suspension, safepoints etc,
3446 3446 // within hotspot. Now there is a single use-case for this:
3447 3447 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3448 3448 // that runs in the watcher thread.
3449 3449 // The remaining code is greatly simplified from the more general suspension
3450 3450 // code that used to be used.
3451 3451 //
3452 3452 // The protocol is quite simple:
3453 3453 // - suspend:
3454 3454 // - sends a signal to the target thread
3455 3455 // - polls the suspend state of the osthread using a yield loop
3456 3456 // - target thread signal handler (SR_handler) sets suspend state
3457 3457 // and blocks in sigsuspend until continued
3458 3458 // - resume:
3459 3459 // - sets target osthread state to continue
3460 3460 // - sends signal to end the sigsuspend loop in the SR_handler
3461 3461 //
3462 3462 // Note that the SR_lock plays no role in this suspend/resume protocol.
3463 3463 //
3464 3464
3465 3465 static void resume_clear_context(OSThread *osthread) {
3466 3466 osthread->set_ucontext(NULL);
3467 3467 osthread->set_siginfo(NULL);
3468 3468
3469 3469 // notify the suspend action is completed, we have now resumed
3470 3470 osthread->sr.clear_suspended();
3471 3471 }
3472 3472
3473 3473 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3474 3474 osthread->set_ucontext(context);
3475 3475 osthread->set_siginfo(siginfo);
3476 3476 }
3477 3477
3478 3478 //
3479 3479 // Handler function invoked when a thread's execution is suspended or
3480 3480 // resumed. We have to be careful that only async-safe functions are
3481 3481 // called here (Note: most pthread functions are not async safe and
3482 3482 // should be avoided.)
3483 3483 //
3484 3484 // Note: sigwait() is a more natural fit than sigsuspend() from an
3485 3485 // interface point of view, but sigwait() prevents the signal hander
3486 3486 // from being run. libpthread would get very confused by not having
3487 3487 // its signal handlers run and prevents sigwait()'s use with the
3488 3488 // mutex granting granting signal.
3489 3489 //
3490 3490 // Currently only ever called on the VMThread
3491 3491 //
3492 3492 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3493 3493 // Save and restore errno to avoid confusing native code with EINTR
3494 3494 // after sigsuspend.
3495 3495 int old_errno = errno;
3496 3496
3497 3497 Thread* thread = Thread::current();
3498 3498 OSThread* osthread = thread->osthread();
3499 3499 assert(thread->is_VM_thread(), "Must be VMThread");
3500 3500 // read current suspend action
3501 3501 int action = osthread->sr.suspend_action();
3502 3502 if (action == SR_SUSPEND) {
3503 3503 suspend_save_context(osthread, siginfo, context);
3504 3504
3505 3505 // Notify the suspend action is about to be completed. do_suspend()
3506 3506 // waits until SR_SUSPENDED is set and then returns. We will wait
3507 3507 // here for a resume signal and that completes the suspend-other
3508 3508 // action. do_suspend/do_resume is always called as a pair from
3509 3509 // the same thread - so there are no races
3510 3510
3511 3511 // notify the caller
3512 3512 osthread->sr.set_suspended();
3513 3513
3514 3514 sigset_t suspend_set; // signals for sigsuspend()
3515 3515
3516 3516 // get current set of blocked signals and unblock resume signal
3517 3517 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3518 3518 sigdelset(&suspend_set, SR_signum);
3519 3519
3520 3520 // wait here until we are resumed
3521 3521 do {
3522 3522 sigsuspend(&suspend_set);
3523 3523 // ignore all returns until we get a resume signal
3524 3524 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3525 3525
3526 3526 resume_clear_context(osthread);
3527 3527
3528 3528 } else {
3529 3529 assert(action == SR_CONTINUE, "unexpected sr action");
3530 3530 // nothing special to do - just leave the handler
3531 3531 }
3532 3532
3533 3533 errno = old_errno;
3534 3534 }
3535 3535
3536 3536
3537 3537 static int SR_initialize() {
3538 3538 struct sigaction act;
3539 3539 char *s;
3540 3540 /* Get signal number to use for suspend/resume */
3541 3541 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3542 3542 int sig = ::strtol(s, 0, 10);
3543 3543 if (sig > 0 || sig < _NSIG) {
3544 3544 SR_signum = sig;
3545 3545 }
3546 3546 }
3547 3547
3548 3548 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3549 3549 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3550 3550
3551 3551 sigemptyset(&SR_sigset);
3552 3552 sigaddset(&SR_sigset, SR_signum);
3553 3553
3554 3554 /* Set up signal handler for suspend/resume */
3555 3555 act.sa_flags = SA_RESTART|SA_SIGINFO;
3556 3556 act.sa_handler = (void (*)(int)) SR_handler;
3557 3557
3558 3558 // SR_signum is blocked by default.
3559 3559 // 4528190 - We also need to block pthread restart signal (32 on all
3560 3560 // supported Linux platforms). Note that LinuxThreads need to block
3561 3561 // this signal for all threads to work properly. So we don't have
3562 3562 // to use hard-coded signal number when setting up the mask.
3563 3563 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3564 3564
3565 3565 if (sigaction(SR_signum, &act, 0) == -1) {
3566 3566 return -1;
3567 3567 }
3568 3568
3569 3569 // Save signal flag
3570 3570 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3571 3571 return 0;
3572 3572 }
3573 3573
3574 3574 static int SR_finalize() {
3575 3575 return 0;
3576 3576 }
3577 3577
3578 3578
3579 3579 // returns true on success and false on error - really an error is fatal
3580 3580 // but this seems the normal response to library errors
3581 3581 static bool do_suspend(OSThread* osthread) {
3582 3582 // mark as suspended and send signal
3583 3583 osthread->sr.set_suspend_action(SR_SUSPEND);
3584 3584 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3585 3585 assert_status(status == 0, status, "pthread_kill");
3586 3586
3587 3587 // check status and wait until notified of suspension
3588 3588 if (status == 0) {
3589 3589 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3590 3590 os::yield_all(i);
3591 3591 }
3592 3592 osthread->sr.set_suspend_action(SR_NONE);
3593 3593 return true;
3594 3594 }
3595 3595 else {
3596 3596 osthread->sr.set_suspend_action(SR_NONE);
3597 3597 return false;
3598 3598 }
3599 3599 }
3600 3600
3601 3601 static void do_resume(OSThread* osthread) {
3602 3602 assert(osthread->sr.is_suspended(), "thread should be suspended");
3603 3603 osthread->sr.set_suspend_action(SR_CONTINUE);
3604 3604
3605 3605 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3606 3606 assert_status(status == 0, status, "pthread_kill");
3607 3607 // check status and wait unit notified of resumption
3608 3608 if (status == 0) {
3609 3609 for (int i = 0; osthread->sr.is_suspended(); i++) {
3610 3610 os::yield_all(i);
3611 3611 }
3612 3612 }
3613 3613 osthread->sr.set_suspend_action(SR_NONE);
3614 3614 }
3615 3615
3616 3616 ////////////////////////////////////////////////////////////////////////////////
3617 3617 // interrupt support
3618 3618
3619 3619 void os::interrupt(Thread* thread) {
3620 3620 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3621 3621 "possibility of dangling Thread pointer");
3622 3622
3623 3623 OSThread* osthread = thread->osthread();
3624 3624
3625 3625 if (!osthread->interrupted()) {
3626 3626 osthread->set_interrupted(true);
3627 3627 // More than one thread can get here with the same value of osthread,
3628 3628 // resulting in multiple notifications. We do, however, want the store
3629 3629 // to interrupted() to be visible to other threads before we execute unpark().
3630 3630 OrderAccess::fence();
3631 3631 ParkEvent * const slp = thread->_SleepEvent ;
3632 3632 if (slp != NULL) slp->unpark() ;
3633 3633 }
3634 3634
3635 3635 // For JSR166. Unpark even if interrupt status already was set
3636 3636 if (thread->is_Java_thread())
3637 3637 ((JavaThread*)thread)->parker()->unpark();
3638 3638
3639 3639 ParkEvent * ev = thread->_ParkEvent ;
3640 3640 if (ev != NULL) ev->unpark() ;
3641 3641
3642 3642 }
3643 3643
3644 3644 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3645 3645 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3646 3646 "possibility of dangling Thread pointer");
3647 3647
3648 3648 OSThread* osthread = thread->osthread();
3649 3649
3650 3650 bool interrupted = osthread->interrupted();
3651 3651
3652 3652 if (interrupted && clear_interrupted) {
3653 3653 osthread->set_interrupted(false);
3654 3654 // consider thread->_SleepEvent->reset() ... optional optimization
3655 3655 }
3656 3656
3657 3657 return interrupted;
3658 3658 }
3659 3659
3660 3660 ///////////////////////////////////////////////////////////////////////////////////
3661 3661 // signal handling (except suspend/resume)
3662 3662
3663 3663 // This routine may be used by user applications as a "hook" to catch signals.
3664 3664 // The user-defined signal handler must pass unrecognized signals to this
3665 3665 // routine, and if it returns true (non-zero), then the signal handler must
3666 3666 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3667 3667 // routine will never retun false (zero), but instead will execute a VM panic
3668 3668 // routine kill the process.
3669 3669 //
3670 3670 // If this routine returns false, it is OK to call it again. This allows
3671 3671 // the user-defined signal handler to perform checks either before or after
3672 3672 // the VM performs its own checks. Naturally, the user code would be making
3673 3673 // a serious error if it tried to handle an exception (such as a null check
3674 3674 // or breakpoint) that the VM was generating for its own correct operation.
3675 3675 //
3676 3676 // This routine may recognize any of the following kinds of signals:
3677 3677 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3678 3678 // It should be consulted by handlers for any of those signals.
3679 3679 //
3680 3680 // The caller of this routine must pass in the three arguments supplied
3681 3681 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3682 3682 // field of the structure passed to sigaction(). This routine assumes that
3683 3683 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3684 3684 //
3685 3685 // Note that the VM will print warnings if it detects conflicting signal
3686 3686 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3687 3687 //
3688 3688 extern "C" JNIEXPORT int
3689 3689 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3690 3690 void* ucontext, int abort_if_unrecognized);
3691 3691
3692 3692 void signalHandler(int sig, siginfo_t* info, void* uc) {
3693 3693 assert(info != NULL && uc != NULL, "it must be old kernel");
3694 3694 JVM_handle_linux_signal(sig, info, uc, true);
3695 3695 }
3696 3696
3697 3697
3698 3698 // This boolean allows users to forward their own non-matching signals
3699 3699 // to JVM_handle_linux_signal, harmlessly.
3700 3700 bool os::Linux::signal_handlers_are_installed = false;
3701 3701
3702 3702 // For signal-chaining
3703 3703 struct sigaction os::Linux::sigact[MAXSIGNUM];
3704 3704 unsigned int os::Linux::sigs = 0;
3705 3705 bool os::Linux::libjsig_is_loaded = false;
3706 3706 typedef struct sigaction *(*get_signal_t)(int);
3707 3707 get_signal_t os::Linux::get_signal_action = NULL;
3708 3708
3709 3709 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3710 3710 struct sigaction *actp = NULL;
3711 3711
3712 3712 if (libjsig_is_loaded) {
3713 3713 // Retrieve the old signal handler from libjsig
3714 3714 actp = (*get_signal_action)(sig);
3715 3715 }
3716 3716 if (actp == NULL) {
3717 3717 // Retrieve the preinstalled signal handler from jvm
3718 3718 actp = get_preinstalled_handler(sig);
3719 3719 }
3720 3720
3721 3721 return actp;
3722 3722 }
3723 3723
3724 3724 static bool call_chained_handler(struct sigaction *actp, int sig,
3725 3725 siginfo_t *siginfo, void *context) {
3726 3726 // Call the old signal handler
3727 3727 if (actp->sa_handler == SIG_DFL) {
3728 3728 // It's more reasonable to let jvm treat it as an unexpected exception
3729 3729 // instead of taking the default action.
3730 3730 return false;
3731 3731 } else if (actp->sa_handler != SIG_IGN) {
3732 3732 if ((actp->sa_flags & SA_NODEFER) == 0) {
3733 3733 // automaticlly block the signal
3734 3734 sigaddset(&(actp->sa_mask), sig);
3735 3735 }
3736 3736
3737 3737 sa_handler_t hand;
3738 3738 sa_sigaction_t sa;
3739 3739 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3740 3740 // retrieve the chained handler
3741 3741 if (siginfo_flag_set) {
3742 3742 sa = actp->sa_sigaction;
3743 3743 } else {
3744 3744 hand = actp->sa_handler;
3745 3745 }
3746 3746
3747 3747 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3748 3748 actp->sa_handler = SIG_DFL;
3749 3749 }
3750 3750
3751 3751 // try to honor the signal mask
3752 3752 sigset_t oset;
3753 3753 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3754 3754
3755 3755 // call into the chained handler
3756 3756 if (siginfo_flag_set) {
3757 3757 (*sa)(sig, siginfo, context);
3758 3758 } else {
3759 3759 (*hand)(sig);
3760 3760 }
3761 3761
3762 3762 // restore the signal mask
3763 3763 pthread_sigmask(SIG_SETMASK, &oset, 0);
3764 3764 }
3765 3765 // Tell jvm's signal handler the signal is taken care of.
3766 3766 return true;
3767 3767 }
3768 3768
3769 3769 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3770 3770 bool chained = false;
3771 3771 // signal-chaining
3772 3772 if (UseSignalChaining) {
3773 3773 struct sigaction *actp = get_chained_signal_action(sig);
3774 3774 if (actp != NULL) {
3775 3775 chained = call_chained_handler(actp, sig, siginfo, context);
3776 3776 }
3777 3777 }
3778 3778 return chained;
3779 3779 }
3780 3780
3781 3781 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3782 3782 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3783 3783 return &sigact[sig];
3784 3784 }
3785 3785 return NULL;
3786 3786 }
3787 3787
3788 3788 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3789 3789 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3790 3790 sigact[sig] = oldAct;
3791 3791 sigs |= (unsigned int)1 << sig;
3792 3792 }
3793 3793
3794 3794 // for diagnostic
3795 3795 int os::Linux::sigflags[MAXSIGNUM];
3796 3796
3797 3797 int os::Linux::get_our_sigflags(int sig) {
3798 3798 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3799 3799 return sigflags[sig];
3800 3800 }
3801 3801
3802 3802 void os::Linux::set_our_sigflags(int sig, int flags) {
3803 3803 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3804 3804 sigflags[sig] = flags;
3805 3805 }
3806 3806
3807 3807 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3808 3808 // Check for overwrite.
3809 3809 struct sigaction oldAct;
3810 3810 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3811 3811
3812 3812 void* oldhand = oldAct.sa_sigaction
3813 3813 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3814 3814 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3815 3815 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3816 3816 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3817 3817 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3818 3818 if (AllowUserSignalHandlers || !set_installed) {
3819 3819 // Do not overwrite; user takes responsibility to forward to us.
3820 3820 return;
3821 3821 } else if (UseSignalChaining) {
3822 3822 // save the old handler in jvm
3823 3823 save_preinstalled_handler(sig, oldAct);
3824 3824 // libjsig also interposes the sigaction() call below and saves the
3825 3825 // old sigaction on it own.
3826 3826 } else {
3827 3827 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3828 3828 "%#lx for signal %d.", (long)oldhand, sig));
3829 3829 }
3830 3830 }
3831 3831
3832 3832 struct sigaction sigAct;
3833 3833 sigfillset(&(sigAct.sa_mask));
3834 3834 sigAct.sa_handler = SIG_DFL;
3835 3835 if (!set_installed) {
3836 3836 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3837 3837 } else {
3838 3838 sigAct.sa_sigaction = signalHandler;
3839 3839 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3840 3840 }
3841 3841 // Save flags, which are set by ours
3842 3842 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3843 3843 sigflags[sig] = sigAct.sa_flags;
3844 3844
3845 3845 int ret = sigaction(sig, &sigAct, &oldAct);
3846 3846 assert(ret == 0, "check");
3847 3847
3848 3848 void* oldhand2 = oldAct.sa_sigaction
3849 3849 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3850 3850 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3851 3851 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3852 3852 }
3853 3853
3854 3854 // install signal handlers for signals that HotSpot needs to
3855 3855 // handle in order to support Java-level exception handling.
3856 3856
3857 3857 void os::Linux::install_signal_handlers() {
3858 3858 if (!signal_handlers_are_installed) {
3859 3859 signal_handlers_are_installed = true;
3860 3860
3861 3861 // signal-chaining
3862 3862 typedef void (*signal_setting_t)();
3863 3863 signal_setting_t begin_signal_setting = NULL;
3864 3864 signal_setting_t end_signal_setting = NULL;
3865 3865 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3866 3866 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3867 3867 if (begin_signal_setting != NULL) {
3868 3868 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3869 3869 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3870 3870 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3871 3871 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3872 3872 libjsig_is_loaded = true;
3873 3873 assert(UseSignalChaining, "should enable signal-chaining");
3874 3874 }
3875 3875 if (libjsig_is_loaded) {
3876 3876 // Tell libjsig jvm is setting signal handlers
3877 3877 (*begin_signal_setting)();
3878 3878 }
3879 3879
3880 3880 set_signal_handler(SIGSEGV, true);
3881 3881 set_signal_handler(SIGPIPE, true);
3882 3882 set_signal_handler(SIGBUS, true);
3883 3883 set_signal_handler(SIGILL, true);
3884 3884 set_signal_handler(SIGFPE, true);
3885 3885 set_signal_handler(SIGXFSZ, true);
3886 3886
3887 3887 if (libjsig_is_loaded) {
3888 3888 // Tell libjsig jvm finishes setting signal handlers
3889 3889 (*end_signal_setting)();
3890 3890 }
3891 3891
3892 3892 // We don't activate signal checker if libjsig is in place, we trust ourselves
3893 3893 // and if UserSignalHandler is installed all bets are off.
3894 3894 // Log that signal checking is off only if -verbose:jni is specified.
3895 3895 if (CheckJNICalls) {
3896 3896 if (libjsig_is_loaded) {
3897 3897 if (PrintJNIResolving) {
3898 3898 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3899 3899 }
3900 3900 check_signals = false;
3901 3901 }
3902 3902 if (AllowUserSignalHandlers) {
3903 3903 if (PrintJNIResolving) {
3904 3904 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3905 3905 }
3906 3906 check_signals = false;
3907 3907 }
3908 3908 }
3909 3909 }
3910 3910 }
3911 3911
3912 3912 // This is the fastest way to get thread cpu time on Linux.
3913 3913 // Returns cpu time (user+sys) for any thread, not only for current.
3914 3914 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3915 3915 // It might work on 2.6.10+ with a special kernel/glibc patch.
3916 3916 // For reference, please, see IEEE Std 1003.1-2004:
3917 3917 // http://www.unix.org/single_unix_specification
3918 3918
3919 3919 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3920 3920 struct timespec tp;
3921 3921 int rc = os::Linux::clock_gettime(clockid, &tp);
3922 3922 assert(rc == 0, "clock_gettime is expected to return 0 code");
3923 3923
3924 3924 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
3925 3925 }
3926 3926
3927 3927 /////
3928 3928 // glibc on Linux platform uses non-documented flag
3929 3929 // to indicate, that some special sort of signal
3930 3930 // trampoline is used.
3931 3931 // We will never set this flag, and we should
3932 3932 // ignore this flag in our diagnostic
3933 3933 #ifdef SIGNIFICANT_SIGNAL_MASK
3934 3934 #undef SIGNIFICANT_SIGNAL_MASK
3935 3935 #endif
3936 3936 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3937 3937
3938 3938 static const char* get_signal_handler_name(address handler,
3939 3939 char* buf, int buflen) {
3940 3940 int offset;
3941 3941 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3942 3942 if (found) {
3943 3943 // skip directory names
3944 3944 const char *p1, *p2;
3945 3945 p1 = buf;
3946 3946 size_t len = strlen(os::file_separator());
3947 3947 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3948 3948 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3949 3949 } else {
3950 3950 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3951 3951 }
3952 3952 return buf;
3953 3953 }
3954 3954
3955 3955 static void print_signal_handler(outputStream* st, int sig,
3956 3956 char* buf, size_t buflen) {
3957 3957 struct sigaction sa;
3958 3958
3959 3959 sigaction(sig, NULL, &sa);
3960 3960
3961 3961 // See comment for SIGNIFICANT_SIGNAL_MASK define
3962 3962 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3963 3963
3964 3964 st->print("%s: ", os::exception_name(sig, buf, buflen));
3965 3965
3966 3966 address handler = (sa.sa_flags & SA_SIGINFO)
3967 3967 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3968 3968 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3969 3969
3970 3970 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3971 3971 st->print("SIG_DFL");
3972 3972 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3973 3973 st->print("SIG_IGN");
3974 3974 } else {
3975 3975 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3976 3976 }
3977 3977
3978 3978 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3979 3979
3980 3980 address rh = VMError::get_resetted_sighandler(sig);
3981 3981 // May be, handler was resetted by VMError?
3982 3982 if(rh != NULL) {
3983 3983 handler = rh;
3984 3984 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3985 3985 }
3986 3986
3987 3987 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3988 3988
3989 3989 // Check: is it our handler?
3990 3990 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3991 3991 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3992 3992 // It is our signal handler
3993 3993 // check for flags, reset system-used one!
3994 3994 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3995 3995 st->print(
3996 3996 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3997 3997 os::Linux::get_our_sigflags(sig));
3998 3998 }
3999 3999 }
4000 4000 st->cr();
4001 4001 }
4002 4002
4003 4003
4004 4004 #define DO_SIGNAL_CHECK(sig) \
4005 4005 if (!sigismember(&check_signal_done, sig)) \
4006 4006 os::Linux::check_signal_handler(sig)
4007 4007
4008 4008 // This method is a periodic task to check for misbehaving JNI applications
4009 4009 // under CheckJNI, we can add any periodic checks here
4010 4010
4011 4011 void os::run_periodic_checks() {
4012 4012
4013 4013 if (check_signals == false) return;
4014 4014
4015 4015 // SEGV and BUS if overridden could potentially prevent
4016 4016 // generation of hs*.log in the event of a crash, debugging
4017 4017 // such a case can be very challenging, so we absolutely
4018 4018 // check the following for a good measure:
4019 4019 DO_SIGNAL_CHECK(SIGSEGV);
4020 4020 DO_SIGNAL_CHECK(SIGILL);
4021 4021 DO_SIGNAL_CHECK(SIGFPE);
4022 4022 DO_SIGNAL_CHECK(SIGBUS);
4023 4023 DO_SIGNAL_CHECK(SIGPIPE);
4024 4024 DO_SIGNAL_CHECK(SIGXFSZ);
4025 4025
4026 4026
4027 4027 // ReduceSignalUsage allows the user to override these handlers
4028 4028 // see comments at the very top and jvm_solaris.h
4029 4029 if (!ReduceSignalUsage) {
4030 4030 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4031 4031 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4032 4032 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4033 4033 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4034 4034 }
4035 4035
4036 4036 DO_SIGNAL_CHECK(SR_signum);
4037 4037 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4038 4038 }
4039 4039
4040 4040 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4041 4041
4042 4042 static os_sigaction_t os_sigaction = NULL;
4043 4043
4044 4044 void os::Linux::check_signal_handler(int sig) {
4045 4045 char buf[O_BUFLEN];
4046 4046 address jvmHandler = NULL;
4047 4047
4048 4048
4049 4049 struct sigaction act;
4050 4050 if (os_sigaction == NULL) {
4051 4051 // only trust the default sigaction, in case it has been interposed
4052 4052 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4053 4053 if (os_sigaction == NULL) return;
4054 4054 }
4055 4055
4056 4056 os_sigaction(sig, (struct sigaction*)NULL, &act);
4057 4057
4058 4058
4059 4059 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4060 4060
4061 4061 address thisHandler = (act.sa_flags & SA_SIGINFO)
4062 4062 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4063 4063 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4064 4064
4065 4065
4066 4066 switch(sig) {
4067 4067 case SIGSEGV:
4068 4068 case SIGBUS:
4069 4069 case SIGFPE:
4070 4070 case SIGPIPE:
4071 4071 case SIGILL:
4072 4072 case SIGXFSZ:
4073 4073 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4074 4074 break;
4075 4075
4076 4076 case SHUTDOWN1_SIGNAL:
4077 4077 case SHUTDOWN2_SIGNAL:
4078 4078 case SHUTDOWN3_SIGNAL:
4079 4079 case BREAK_SIGNAL:
4080 4080 jvmHandler = (address)user_handler();
4081 4081 break;
4082 4082
4083 4083 case INTERRUPT_SIGNAL:
4084 4084 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4085 4085 break;
4086 4086
4087 4087 default:
4088 4088 if (sig == SR_signum) {
4089 4089 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4090 4090 } else {
4091 4091 return;
4092 4092 }
4093 4093 break;
4094 4094 }
4095 4095
4096 4096 if (thisHandler != jvmHandler) {
4097 4097 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4098 4098 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4099 4099 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4100 4100 // No need to check this sig any longer
4101 4101 sigaddset(&check_signal_done, sig);
4102 4102 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4103 4103 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4104 4104 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4105 4105 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4106 4106 // No need to check this sig any longer
4107 4107 sigaddset(&check_signal_done, sig);
4108 4108 }
4109 4109
4110 4110 // Dump all the signal
4111 4111 if (sigismember(&check_signal_done, sig)) {
4112 4112 print_signal_handlers(tty, buf, O_BUFLEN);
4113 4113 }
4114 4114 }
4115 4115
4116 4116 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4117 4117
4118 4118 extern bool signal_name(int signo, char* buf, size_t len);
4119 4119
4120 4120 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4121 4121 if (0 < exception_code && exception_code <= SIGRTMAX) {
4122 4122 // signal
4123 4123 if (!signal_name(exception_code, buf, size)) {
4124 4124 jio_snprintf(buf, size, "SIG%d", exception_code);
4125 4125 }
4126 4126 return buf;
4127 4127 } else {
4128 4128 return NULL;
4129 4129 }
4130 4130 }
4131 4131
4132 4132 // this is called _before_ the most of global arguments have been parsed
4133 4133 void os::init(void) {
4134 4134 char dummy; /* used to get a guess on initial stack address */
4135 4135 // first_hrtime = gethrtime();
4136 4136
4137 4137 // With LinuxThreads the JavaMain thread pid (primordial thread)
4138 4138 // is different than the pid of the java launcher thread.
4139 4139 // So, on Linux, the launcher thread pid is passed to the VM
4140 4140 // via the sun.java.launcher.pid property.
4141 4141 // Use this property instead of getpid() if it was correctly passed.
4142 4142 // See bug 6351349.
4143 4143 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4144 4144
4145 4145 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4146 4146
4147 4147 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4148 4148
4149 4149 init_random(1234567);
4150 4150
4151 4151 ThreadCritical::initialize();
4152 4152
4153 4153 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4154 4154 if (Linux::page_size() == -1) {
4155 4155 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4156 4156 strerror(errno)));
4157 4157 }
4158 4158 init_page_sizes((size_t) Linux::page_size());
4159 4159
4160 4160 Linux::initialize_system_info();
4161 4161
4162 4162 // main_thread points to the aboriginal thread
4163 4163 Linux::_main_thread = pthread_self();
4164 4164
4165 4165 Linux::clock_init();
4166 4166 initial_time_count = os::elapsed_counter();
4167 4167 pthread_mutex_init(&dl_mutex, NULL);
4168 4168 }
4169 4169
4170 4170 // To install functions for atexit system call
4171 4171 extern "C" {
4172 4172 static void perfMemory_exit_helper() {
4173 4173 perfMemory_exit();
4174 4174 }
4175 4175 }
4176 4176
4177 4177 // this is called _after_ the global arguments have been parsed
4178 4178 jint os::init_2(void)
4179 4179 {
4180 4180 Linux::fast_thread_clock_init();
4181 4181
4182 4182 // Allocate a single page and mark it as readable for safepoint polling
4183 4183 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4184 4184 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4185 4185
4186 4186 os::set_polling_page( polling_page );
4187 4187
4188 4188 #ifndef PRODUCT
4189 4189 if(Verbose && PrintMiscellaneous)
4190 4190 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4191 4191 #endif
4192 4192
4193 4193 if (!UseMembar) {
4194 4194 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4195 4195 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4196 4196 os::set_memory_serialize_page( mem_serialize_page );
4197 4197
4198 4198 #ifndef PRODUCT
4199 4199 if(Verbose && PrintMiscellaneous)
4200 4200 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4201 4201 #endif
4202 4202 }
4203 4203
4204 4204 os::large_page_init();
4205 4205
4206 4206 // initialize suspend/resume support - must do this before signal_sets_init()
4207 4207 if (SR_initialize() != 0) {
4208 4208 perror("SR_initialize failed");
4209 4209 return JNI_ERR;
4210 4210 }
4211 4211
4212 4212 Linux::signal_sets_init();
4213 4213 Linux::install_signal_handlers();
4214 4214
4215 4215 // Check minimum allowable stack size for thread creation and to initialize
4216 4216 // the java system classes, including StackOverflowError - depends on page
4217 4217 // size. Add a page for compiler2 recursion in main thread.
4218 4218 // Add in 2*BytesPerWord times page size to account for VM stack during
4219 4219 // class initialization depending on 32 or 64 bit VM.
4220 4220 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4221 4221 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4222 4222 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4223 4223
4224 4224 size_t threadStackSizeInBytes = ThreadStackSize * K;
4225 4225 if (threadStackSizeInBytes != 0 &&
4226 4226 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4227 4227 tty->print_cr("\nThe stack size specified is too small, "
4228 4228 "Specify at least %dk",
4229 4229 os::Linux::min_stack_allowed/ K);
4230 4230 return JNI_ERR;
4231 4231 }
4232 4232
4233 4233 // Make the stack size a multiple of the page size so that
4234 4234 // the yellow/red zones can be guarded.
4235 4235 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4236 4236 vm_page_size()));
4237 4237
4238 4238 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4239 4239
4240 4240 Linux::libpthread_init();
4241 4241 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4242 4242 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4243 4243 Linux::glibc_version(), Linux::libpthread_version(),
4244 4244 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4245 4245 }
4246 4246
4247 4247 if (UseNUMA) {
4248 4248 if (!Linux::libnuma_init()) {
4249 4249 UseNUMA = false;
4250 4250 } else {
4251 4251 if ((Linux::numa_max_node() < 1)) {
4252 4252 // There's only one node(they start from 0), disable NUMA.
4253 4253 UseNUMA = false;
4254 4254 }
4255 4255 }
4256 4256 // With SHM large pages we cannot uncommit a page, so there's not way
4257 4257 // we can make the adaptive lgrp chunk resizing work. If the user specified
4258 4258 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4259 4259 // disable adaptive resizing.
4260 4260 if (UseNUMA && UseLargePages && UseSHM) {
4261 4261 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4262 4262 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4263 4263 UseLargePages = false;
4264 4264 } else {
4265 4265 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4266 4266 UseAdaptiveSizePolicy = false;
4267 4267 UseAdaptiveNUMAChunkSizing = false;
4268 4268 }
4269 4269 } else {
4270 4270 UseNUMA = false;
4271 4271 }
4272 4272 }
4273 4273 if (!UseNUMA && ForceNUMA) {
4274 4274 UseNUMA = true;
4275 4275 }
4276 4276 }
4277 4277
4278 4278 if (MaxFDLimit) {
4279 4279 // set the number of file descriptors to max. print out error
4280 4280 // if getrlimit/setrlimit fails but continue regardless.
4281 4281 struct rlimit nbr_files;
4282 4282 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4283 4283 if (status != 0) {
4284 4284 if (PrintMiscellaneous && (Verbose || WizardMode))
4285 4285 perror("os::init_2 getrlimit failed");
4286 4286 } else {
4287 4287 nbr_files.rlim_cur = nbr_files.rlim_max;
4288 4288 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4289 4289 if (status != 0) {
4290 4290 if (PrintMiscellaneous && (Verbose || WizardMode))
4291 4291 perror("os::init_2 setrlimit failed");
4292 4292 }
4293 4293 }
4294 4294 }
4295 4295
4296 4296 // Initialize lock used to serialize thread creation (see os::create_thread)
4297 4297 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4298 4298
4299 4299 // at-exit methods are called in the reverse order of their registration.
4300 4300 // atexit functions are called on return from main or as a result of a
4301 4301 // call to exit(3C). There can be only 32 of these functions registered
4302 4302 // and atexit() does not set errno.
4303 4303
4304 4304 if (PerfAllowAtExitRegistration) {
4305 4305 // only register atexit functions if PerfAllowAtExitRegistration is set.
4306 4306 // atexit functions can be delayed until process exit time, which
4307 4307 // can be problematic for embedded VM situations. Embedded VMs should
4308 4308 // call DestroyJavaVM() to assure that VM resources are released.
4309 4309
4310 4310 // note: perfMemory_exit_helper atexit function may be removed in
4311 4311 // the future if the appropriate cleanup code can be added to the
4312 4312 // VM_Exit VMOperation's doit method.
4313 4313 if (atexit(perfMemory_exit_helper) != 0) {
4314 4314 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4315 4315 }
4316 4316 }
4317 4317
4318 4318 // initialize thread priority policy
4319 4319 prio_init();
4320 4320
4321 4321 return JNI_OK;
4322 4322 }
4323 4323
4324 4324 // this is called at the end of vm_initialization
4325 4325 void os::init_3(void)
4326 4326 {
4327 4327 #ifdef JAVASE_EMBEDDED
4328 4328 // Start the MemNotifyThread
4329 4329 if (LowMemoryProtection) {
4330 4330 MemNotifyThread::start();
4331 4331 }
4332 4332 return;
4333 4333 #endif
4334 4334 }
4335 4335
4336 4336 // Mark the polling page as unreadable
4337 4337 void os::make_polling_page_unreadable(void) {
4338 4338 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4339 4339 fatal("Could not disable polling page");
4340 4340 };
4341 4341
4342 4342 // Mark the polling page as readable
4343 4343 void os::make_polling_page_readable(void) {
4344 4344 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4345 4345 fatal("Could not enable polling page");
4346 4346 }
4347 4347 };
4348 4348
4349 4349 int os::active_processor_count() {
4350 4350 // Linux doesn't yet have a (official) notion of processor sets,
4351 4351 // so just return the number of online processors.
4352 4352 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4353 4353 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4354 4354 return online_cpus;
4355 4355 }
4356 4356
4357 4357 void os::set_native_thread_name(const char *name) {
4358 4358 // Not yet implemented.
4359 4359 return;
4360 4360 }
4361 4361
4362 4362 bool os::distribute_processes(uint length, uint* distribution) {
4363 4363 // Not yet implemented.
4364 4364 return false;
4365 4365 }
4366 4366
4367 4367 bool os::bind_to_processor(uint processor_id) {
4368 4368 // Not yet implemented.
4369 4369 return false;
4370 4370 }
4371 4371
4372 4372 ///
4373 4373
4374 4374 // Suspends the target using the signal mechanism and then grabs the PC before
4375 4375 // resuming the target. Used by the flat-profiler only
4376 4376 ExtendedPC os::get_thread_pc(Thread* thread) {
4377 4377 // Make sure that it is called by the watcher for the VMThread
4378 4378 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4379 4379 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4380 4380
4381 4381 ExtendedPC epc;
4382 4382
4383 4383 OSThread* osthread = thread->osthread();
4384 4384 if (do_suspend(osthread)) {
4385 4385 if (osthread->ucontext() != NULL) {
4386 4386 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4387 4387 } else {
4388 4388 // NULL context is unexpected, double-check this is the VMThread
4389 4389 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4390 4390 }
4391 4391 do_resume(osthread);
4392 4392 }
4393 4393 // failure means pthread_kill failed for some reason - arguably this is
4394 4394 // a fatal problem, but such problems are ignored elsewhere
4395 4395
4396 4396 return epc;
4397 4397 }
4398 4398
4399 4399 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4400 4400 {
4401 4401 if (is_NPTL()) {
4402 4402 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4403 4403 } else {
4404 4404 #ifndef IA64
4405 4405 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4406 4406 // word back to default 64bit precision if condvar is signaled. Java
4407 4407 // wants 53bit precision. Save and restore current value.
4408 4408 int fpu = get_fpu_control_word();
4409 4409 #endif // IA64
4410 4410 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4411 4411 #ifndef IA64
4412 4412 set_fpu_control_word(fpu);
4413 4413 #endif // IA64
4414 4414 return status;
4415 4415 }
4416 4416 }
4417 4417
4418 4418 ////////////////////////////////////////////////////////////////////////////////
4419 4419 // debug support
4420 4420
4421 4421 static address same_page(address x, address y) {
4422 4422 int page_bits = -os::vm_page_size();
4423 4423 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4424 4424 return x;
4425 4425 else if (x > y)
4426 4426 return (address)(intptr_t(y) | ~page_bits) + 1;
4427 4427 else
4428 4428 return (address)(intptr_t(y) & page_bits);
4429 4429 }
4430 4430
4431 4431 bool os::find(address addr, outputStream* st) {
4432 4432 Dl_info dlinfo;
4433 4433 memset(&dlinfo, 0, sizeof(dlinfo));
4434 4434 if (dladdr(addr, &dlinfo)) {
4435 4435 st->print(PTR_FORMAT ": ", addr);
4436 4436 if (dlinfo.dli_sname != NULL) {
4437 4437 st->print("%s+%#x", dlinfo.dli_sname,
4438 4438 addr - (intptr_t)dlinfo.dli_saddr);
4439 4439 } else if (dlinfo.dli_fname) {
4440 4440 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4441 4441 } else {
4442 4442 st->print("<absolute address>");
4443 4443 }
4444 4444 if (dlinfo.dli_fname) {
4445 4445 st->print(" in %s", dlinfo.dli_fname);
4446 4446 }
4447 4447 if (dlinfo.dli_fbase) {
4448 4448 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4449 4449 }
4450 4450 st->cr();
4451 4451
4452 4452 if (Verbose) {
4453 4453 // decode some bytes around the PC
4454 4454 address begin = same_page(addr-40, addr);
4455 4455 address end = same_page(addr+40, addr);
4456 4456 address lowest = (address) dlinfo.dli_sname;
4457 4457 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4458 4458 if (begin < lowest) begin = lowest;
4459 4459 Dl_info dlinfo2;
4460 4460 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4461 4461 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4462 4462 end = (address) dlinfo2.dli_saddr;
4463 4463 Disassembler::decode(begin, end, st);
4464 4464 }
4465 4465 return true;
4466 4466 }
4467 4467 return false;
4468 4468 }
4469 4469
4470 4470 ////////////////////////////////////////////////////////////////////////////////
4471 4471 // misc
4472 4472
4473 4473 // This does not do anything on Linux. This is basically a hook for being
4474 4474 // able to use structured exception handling (thread-local exception filters)
4475 4475 // on, e.g., Win32.
4476 4476 void
4477 4477 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4478 4478 JavaCallArguments* args, Thread* thread) {
4479 4479 f(value, method, args, thread);
4480 4480 }
4481 4481
4482 4482 void os::print_statistics() {
4483 4483 }
4484 4484
4485 4485 int os::message_box(const char* title, const char* message) {
4486 4486 int i;
4487 4487 fdStream err(defaultStream::error_fd());
4488 4488 for (i = 0; i < 78; i++) err.print_raw("=");
4489 4489 err.cr();
4490 4490 err.print_raw_cr(title);
4491 4491 for (i = 0; i < 78; i++) err.print_raw("-");
4492 4492 err.cr();
4493 4493 err.print_raw_cr(message);
4494 4494 for (i = 0; i < 78; i++) err.print_raw("=");
4495 4495 err.cr();
4496 4496
4497 4497 char buf[16];
4498 4498 // Prevent process from exiting upon "read error" without consuming all CPU
4499 4499 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4500 4500
4501 4501 return buf[0] == 'y' || buf[0] == 'Y';
4502 4502 }
4503 4503
4504 4504 int os::stat(const char *path, struct stat *sbuf) {
4505 4505 char pathbuf[MAX_PATH];
4506 4506 if (strlen(path) > MAX_PATH - 1) {
4507 4507 errno = ENAMETOOLONG;
4508 4508 return -1;
4509 4509 }
4510 4510 os::native_path(strcpy(pathbuf, path));
4511 4511 return ::stat(pathbuf, sbuf);
4512 4512 }
4513 4513
4514 4514 bool os::check_heap(bool force) {
4515 4515 return true;
4516 4516 }
4517 4517
4518 4518 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4519 4519 return ::vsnprintf(buf, count, format, args);
4520 4520 }
4521 4521
4522 4522 // Is a (classpath) directory empty?
4523 4523 bool os::dir_is_empty(const char* path) {
4524 4524 DIR *dir = NULL;
4525 4525 struct dirent *ptr;
4526 4526
4527 4527 dir = opendir(path);
4528 4528 if (dir == NULL) return true;
4529 4529
4530 4530 /* Scan the directory */
4531 4531 bool result = true;
4532 4532 char buf[sizeof(struct dirent) + MAX_PATH];
4533 4533 while (result && (ptr = ::readdir(dir)) != NULL) {
4534 4534 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4535 4535 result = false;
4536 4536 }
4537 4537 }
4538 4538 closedir(dir);
4539 4539 return result;
4540 4540 }
4541 4541
4542 4542 // This code originates from JDK's sysOpen and open64_w
4543 4543 // from src/solaris/hpi/src/system_md.c
4544 4544
4545 4545 #ifndef O_DELETE
4546 4546 #define O_DELETE 0x10000
4547 4547 #endif
4548 4548
4549 4549 // Open a file. Unlink the file immediately after open returns
4550 4550 // if the specified oflag has the O_DELETE flag set.
4551 4551 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4552 4552
4553 4553 int os::open(const char *path, int oflag, int mode) {
4554 4554
4555 4555 if (strlen(path) > MAX_PATH - 1) {
4556 4556 errno = ENAMETOOLONG;
4557 4557 return -1;
4558 4558 }
4559 4559 int fd;
4560 4560 int o_delete = (oflag & O_DELETE);
4561 4561 oflag = oflag & ~O_DELETE;
4562 4562
4563 4563 fd = ::open64(path, oflag, mode);
4564 4564 if (fd == -1) return -1;
4565 4565
4566 4566 //If the open succeeded, the file might still be a directory
4567 4567 {
4568 4568 struct stat64 buf64;
4569 4569 int ret = ::fstat64(fd, &buf64);
4570 4570 int st_mode = buf64.st_mode;
4571 4571
4572 4572 if (ret != -1) {
4573 4573 if ((st_mode & S_IFMT) == S_IFDIR) {
4574 4574 errno = EISDIR;
4575 4575 ::close(fd);
4576 4576 return -1;
4577 4577 }
4578 4578 } else {
4579 4579 ::close(fd);
4580 4580 return -1;
4581 4581 }
4582 4582 }
4583 4583
4584 4584 /*
4585 4585 * All file descriptors that are opened in the JVM and not
4586 4586 * specifically destined for a subprocess should have the
4587 4587 * close-on-exec flag set. If we don't set it, then careless 3rd
4588 4588 * party native code might fork and exec without closing all
4589 4589 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4590 4590 * UNIXProcess.c), and this in turn might:
4591 4591 *
4592 4592 * - cause end-of-file to fail to be detected on some file
4593 4593 * descriptors, resulting in mysterious hangs, or
4594 4594 *
4595 4595 * - might cause an fopen in the subprocess to fail on a system
4596 4596 * suffering from bug 1085341.
4597 4597 *
4598 4598 * (Yes, the default setting of the close-on-exec flag is a Unix
4599 4599 * design flaw)
4600 4600 *
4601 4601 * See:
4602 4602 * 1085341: 32-bit stdio routines should support file descriptors >255
4603 4603 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4604 4604 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4605 4605 */
4606 4606 #ifdef FD_CLOEXEC
4607 4607 {
4608 4608 int flags = ::fcntl(fd, F_GETFD);
4609 4609 if (flags != -1)
4610 4610 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4611 4611 }
4612 4612 #endif
4613 4613
4614 4614 if (o_delete != 0) {
4615 4615 ::unlink(path);
4616 4616 }
4617 4617 return fd;
4618 4618 }
4619 4619
4620 4620
4621 4621 // create binary file, rewriting existing file if required
4622 4622 int os::create_binary_file(const char* path, bool rewrite_existing) {
4623 4623 int oflags = O_WRONLY | O_CREAT;
4624 4624 if (!rewrite_existing) {
4625 4625 oflags |= O_EXCL;
4626 4626 }
4627 4627 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4628 4628 }
4629 4629
4630 4630 // return current position of file pointer
4631 4631 jlong os::current_file_offset(int fd) {
4632 4632 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4633 4633 }
4634 4634
4635 4635 // move file pointer to the specified offset
4636 4636 jlong os::seek_to_file_offset(int fd, jlong offset) {
4637 4637 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4638 4638 }
4639 4639
4640 4640 // This code originates from JDK's sysAvailable
4641 4641 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4642 4642
4643 4643 int os::available(int fd, jlong *bytes) {
4644 4644 jlong cur, end;
4645 4645 int mode;
4646 4646 struct stat64 buf64;
4647 4647
4648 4648 if (::fstat64(fd, &buf64) >= 0) {
4649 4649 mode = buf64.st_mode;
4650 4650 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4651 4651 /*
4652 4652 * XXX: is the following call interruptible? If so, this might
4653 4653 * need to go through the INTERRUPT_IO() wrapper as for other
4654 4654 * blocking, interruptible calls in this file.
4655 4655 */
4656 4656 int n;
4657 4657 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4658 4658 *bytes = n;
4659 4659 return 1;
4660 4660 }
4661 4661 }
4662 4662 }
4663 4663 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4664 4664 return 0;
4665 4665 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4666 4666 return 0;
4667 4667 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4668 4668 return 0;
4669 4669 }
4670 4670 *bytes = end - cur;
4671 4671 return 1;
4672 4672 }
4673 4673
4674 4674 int os::socket_available(int fd, jint *pbytes) {
4675 4675 // Linux doc says EINTR not returned, unlike Solaris
4676 4676 int ret = ::ioctl(fd, FIONREAD, pbytes);
4677 4677
4678 4678 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4679 4679 // is expected to return 0 on failure and 1 on success to the jdk.
4680 4680 return (ret < 0) ? 0 : 1;
4681 4681 }
4682 4682
4683 4683 // Map a block of memory.
4684 4684 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4685 4685 char *addr, size_t bytes, bool read_only,
4686 4686 bool allow_exec) {
4687 4687 int prot;
4688 4688 int flags;
4689 4689
4690 4690 if (read_only) {
4691 4691 prot = PROT_READ;
4692 4692 flags = MAP_SHARED;
4693 4693 } else {
4694 4694 prot = PROT_READ | PROT_WRITE;
4695 4695 flags = MAP_PRIVATE;
4696 4696 }
4697 4697
4698 4698 if (allow_exec) {
4699 4699 prot |= PROT_EXEC;
4700 4700 }
4701 4701
4702 4702 if (addr != NULL) {
4703 4703 flags |= MAP_FIXED;
4704 4704 }
4705 4705
4706 4706 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4707 4707 fd, file_offset);
4708 4708 if (mapped_address == MAP_FAILED) {
4709 4709 return NULL;
4710 4710 }
4711 4711 return mapped_address;
4712 4712 }
4713 4713
4714 4714
4715 4715 // Remap a block of memory.
4716 4716 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4717 4717 char *addr, size_t bytes, bool read_only,
4718 4718 bool allow_exec) {
4719 4719 // same as map_memory() on this OS
4720 4720 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4721 4721 allow_exec);
4722 4722 }
4723 4723
4724 4724
4725 4725 // Unmap a block of memory.
4726 4726 bool os::unmap_memory(char* addr, size_t bytes) {
4727 4727 return munmap(addr, bytes) == 0;
4728 4728 }
4729 4729
4730 4730 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4731 4731
4732 4732 static clockid_t thread_cpu_clockid(Thread* thread) {
4733 4733 pthread_t tid = thread->osthread()->pthread_id();
4734 4734 clockid_t clockid;
4735 4735
4736 4736 // Get thread clockid
4737 4737 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4738 4738 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4739 4739 return clockid;
4740 4740 }
4741 4741
4742 4742 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4743 4743 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4744 4744 // of a thread.
4745 4745 //
4746 4746 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4747 4747 // the fast estimate available on the platform.
4748 4748
4749 4749 jlong os::current_thread_cpu_time() {
4750 4750 if (os::Linux::supports_fast_thread_cpu_time()) {
4751 4751 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4752 4752 } else {
4753 4753 // return user + sys since the cost is the same
4754 4754 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4755 4755 }
4756 4756 }
4757 4757
4758 4758 jlong os::thread_cpu_time(Thread* thread) {
4759 4759 // consistent with what current_thread_cpu_time() returns
4760 4760 if (os::Linux::supports_fast_thread_cpu_time()) {
4761 4761 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4762 4762 } else {
4763 4763 return slow_thread_cpu_time(thread, true /* user + sys */);
4764 4764 }
4765 4765 }
4766 4766
4767 4767 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4768 4768 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4769 4769 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4770 4770 } else {
4771 4771 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4772 4772 }
4773 4773 }
4774 4774
4775 4775 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4776 4776 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4777 4777 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4778 4778 } else {
4779 4779 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4780 4780 }
4781 4781 }
4782 4782
4783 4783 //
4784 4784 // -1 on error.
4785 4785 //
4786 4786
4787 4787 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4788 4788 static bool proc_pid_cpu_avail = true;
4789 4789 static bool proc_task_unchecked = true;
4790 4790 static const char *proc_stat_path = "/proc/%d/stat";
4791 4791 pid_t tid = thread->osthread()->thread_id();
4792 4792 int i;
4793 4793 char *s;
4794 4794 char stat[2048];
4795 4795 int statlen;
4796 4796 char proc_name[64];
4797 4797 int count;
4798 4798 long sys_time, user_time;
4799 4799 char string[64];
4800 4800 char cdummy;
4801 4801 int idummy;
4802 4802 long ldummy;
4803 4803 FILE *fp;
4804 4804
4805 4805 // We first try accessing /proc/<pid>/cpu since this is faster to
4806 4806 // process. If this file is not present (linux kernels 2.5 and above)
4807 4807 // then we open /proc/<pid>/stat.
4808 4808 if ( proc_pid_cpu_avail ) {
4809 4809 sprintf(proc_name, "/proc/%d/cpu", tid);
4810 4810 fp = fopen(proc_name, "r");
4811 4811 if ( fp != NULL ) {
4812 4812 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4813 4813 fclose(fp);
4814 4814 if ( count != 3 ) return -1;
4815 4815
4816 4816 if (user_sys_cpu_time) {
4817 4817 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4818 4818 } else {
4819 4819 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4820 4820 }
4821 4821 }
4822 4822 else proc_pid_cpu_avail = false;
4823 4823 }
4824 4824
4825 4825 // The /proc/<tid>/stat aggregates per-process usage on
4826 4826 // new Linux kernels 2.6+ where NPTL is supported.
4827 4827 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4828 4828 // See bug 6328462.
4829 4829 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4830 4830 // and possibly in some other cases, so we check its availability.
4831 4831 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4832 4832 // This is executed only once
4833 4833 proc_task_unchecked = false;
4834 4834 fp = fopen("/proc/self/task", "r");
4835 4835 if (fp != NULL) {
4836 4836 proc_stat_path = "/proc/self/task/%d/stat";
4837 4837 fclose(fp);
4838 4838 }
4839 4839 }
4840 4840
4841 4841 sprintf(proc_name, proc_stat_path, tid);
4842 4842 fp = fopen(proc_name, "r");
4843 4843 if ( fp == NULL ) return -1;
4844 4844 statlen = fread(stat, 1, 2047, fp);
4845 4845 stat[statlen] = '\0';
4846 4846 fclose(fp);
4847 4847
4848 4848 // Skip pid and the command string. Note that we could be dealing with
4849 4849 // weird command names, e.g. user could decide to rename java launcher
4850 4850 // to "java 1.4.2 :)", then the stat file would look like
4851 4851 // 1234 (java 1.4.2 :)) R ... ...
4852 4852 // We don't really need to know the command string, just find the last
4853 4853 // occurrence of ")" and then start parsing from there. See bug 4726580.
4854 4854 s = strrchr(stat, ')');
4855 4855 i = 0;
4856 4856 if (s == NULL ) return -1;
4857 4857
4858 4858 // Skip blank chars
4859 4859 do s++; while (isspace(*s));
4860 4860
4861 4861 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4862 4862 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4863 4863 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4864 4864 &user_time, &sys_time);
4865 4865 if ( count != 13 ) return -1;
4866 4866 if (user_sys_cpu_time) {
4867 4867 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4868 4868 } else {
4869 4869 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4870 4870 }
4871 4871 }
4872 4872
4873 4873 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4874 4874 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4875 4875 info_ptr->may_skip_backward = false; // elapsed time not wall time
4876 4876 info_ptr->may_skip_forward = false; // elapsed time not wall time
4877 4877 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4878 4878 }
4879 4879
4880 4880 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4881 4881 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4882 4882 info_ptr->may_skip_backward = false; // elapsed time not wall time
4883 4883 info_ptr->may_skip_forward = false; // elapsed time not wall time
4884 4884 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4885 4885 }
4886 4886
4887 4887 bool os::is_thread_cpu_time_supported() {
4888 4888 return true;
4889 4889 }
4890 4890
4891 4891 // System loadavg support. Returns -1 if load average cannot be obtained.
4892 4892 // Linux doesn't yet have a (official) notion of processor sets,
4893 4893 // so just return the system wide load average.
4894 4894 int os::loadavg(double loadavg[], int nelem) {
4895 4895 return ::getloadavg(loadavg, nelem);
4896 4896 }
4897 4897
4898 4898 void os::pause() {
4899 4899 char filename[MAX_PATH];
4900 4900 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4901 4901 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4902 4902 } else {
4903 4903 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4904 4904 }
4905 4905
4906 4906 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4907 4907 if (fd != -1) {
4908 4908 struct stat buf;
4909 4909 ::close(fd);
4910 4910 while (::stat(filename, &buf) == 0) {
4911 4911 (void)::poll(NULL, 0, 100);
4912 4912 }
4913 4913 } else {
4914 4914 jio_fprintf(stderr,
4915 4915 "Could not open pause file '%s', continuing immediately.\n", filename);
4916 4916 }
4917 4917 }
4918 4918
4919 4919
4920 4920 // Refer to the comments in os_solaris.cpp park-unpark.
4921 4921 //
4922 4922 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4923 4923 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4924 4924 // For specifics regarding the bug see GLIBC BUGID 261237 :
4925 4925 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4926 4926 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4927 4927 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4928 4928 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4929 4929 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4930 4930 // and monitorenter when we're using 1-0 locking. All those operations may result in
4931 4931 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4932 4932 // of libpthread avoids the problem, but isn't practical.
4933 4933 //
4934 4934 // Possible remedies:
4935 4935 //
4936 4936 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4937 4937 // This is palliative and probabilistic, however. If the thread is preempted
4938 4938 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4939 4939 // than the minimum period may have passed, and the abstime may be stale (in the
4940 4940 // past) resultin in a hang. Using this technique reduces the odds of a hang
4941 4941 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4942 4942 //
4943 4943 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4944 4944 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4945 4945 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4946 4946 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4947 4947 // thread.
4948 4948 //
4949 4949 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4950 4950 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4951 4951 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4952 4952 // This also works well. In fact it avoids kernel-level scalability impediments
4953 4953 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4954 4954 // timers in a graceful fashion.
4955 4955 //
4956 4956 // 4. When the abstime value is in the past it appears that control returns
4957 4957 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4958 4958 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4959 4959 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4960 4960 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4961 4961 // It may be possible to avoid reinitialization by checking the return
4962 4962 // value from pthread_cond_timedwait(). In addition to reinitializing the
4963 4963 // condvar we must establish the invariant that cond_signal() is only called
4964 4964 // within critical sections protected by the adjunct mutex. This prevents
4965 4965 // cond_signal() from "seeing" a condvar that's in the midst of being
4966 4966 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4967 4967 // desirable signal-after-unlock optimization that avoids futile context switching.
4968 4968 //
4969 4969 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4970 4970 // structure when a condvar is used or initialized. cond_destroy() would
4971 4971 // release the helper structure. Our reinitialize-after-timedwait fix
4972 4972 // put excessive stress on malloc/free and locks protecting the c-heap.
4973 4973 //
4974 4974 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4975 4975 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4976 4976 // and only enabling the work-around for vulnerable environments.
4977 4977
4978 4978 // utility to compute the abstime argument to timedwait:
4979 4979 // millis is the relative timeout time
4980 4980 // abstime will be the absolute timeout time
4981 4981 // TODO: replace compute_abstime() with unpackTime()
4982 4982
4983 4983 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4984 4984 if (millis < 0) millis = 0;
4985 4985 struct timeval now;
4986 4986 int status = gettimeofday(&now, NULL);
4987 4987 assert(status == 0, "gettimeofday");
4988 4988 jlong seconds = millis / 1000;
4989 4989 millis %= 1000;
4990 4990 if (seconds > 50000000) { // see man cond_timedwait(3T)
4991 4991 seconds = 50000000;
4992 4992 }
4993 4993 abstime->tv_sec = now.tv_sec + seconds;
4994 4994 long usec = now.tv_usec + millis * 1000;
4995 4995 if (usec >= 1000000) {
4996 4996 abstime->tv_sec += 1;
4997 4997 usec -= 1000000;
4998 4998 }
4999 4999 abstime->tv_nsec = usec * 1000;
5000 5000 return abstime;
5001 5001 }
5002 5002
5003 5003
5004 5004 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5005 5005 // Conceptually TryPark() should be equivalent to park(0).
5006 5006
5007 5007 int os::PlatformEvent::TryPark() {
5008 5008 for (;;) {
5009 5009 const int v = _Event ;
5010 5010 guarantee ((v == 0) || (v == 1), "invariant") ;
5011 5011 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5012 5012 }
5013 5013 }
5014 5014
5015 5015 void os::PlatformEvent::park() { // AKA "down()"
5016 5016 // Invariant: Only the thread associated with the Event/PlatformEvent
5017 5017 // may call park().
5018 5018 // TODO: assert that _Assoc != NULL or _Assoc == Self
5019 5019 int v ;
5020 5020 for (;;) {
5021 5021 v = _Event ;
5022 5022 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5023 5023 }
5024 5024 guarantee (v >= 0, "invariant") ;
5025 5025 if (v == 0) {
5026 5026 // Do this the hard way by blocking ...
5027 5027 int status = pthread_mutex_lock(_mutex);
5028 5028 assert_status(status == 0, status, "mutex_lock");
5029 5029 guarantee (_nParked == 0, "invariant") ;
5030 5030 ++ _nParked ;
5031 5031 while (_Event < 0) {
5032 5032 status = pthread_cond_wait(_cond, _mutex);
5033 5033 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5034 5034 // Treat this the same as if the wait was interrupted
5035 5035 if (status == ETIME) { status = EINTR; }
5036 5036 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5037 5037 }
5038 5038 -- _nParked ;
5039 5039
5040 5040 // In theory we could move the ST of 0 into _Event past the unlock(),
5041 5041 // but then we'd need a MEMBAR after the ST.
5042 5042 _Event = 0 ;
5043 5043 status = pthread_mutex_unlock(_mutex);
5044 5044 assert_status(status == 0, status, "mutex_unlock");
5045 5045 }
5046 5046 guarantee (_Event >= 0, "invariant") ;
5047 5047 }
5048 5048
5049 5049 int os::PlatformEvent::park(jlong millis) {
5050 5050 guarantee (_nParked == 0, "invariant") ;
5051 5051
5052 5052 int v ;
5053 5053 for (;;) {
5054 5054 v = _Event ;
5055 5055 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5056 5056 }
5057 5057 guarantee (v >= 0, "invariant") ;
5058 5058 if (v != 0) return OS_OK ;
5059 5059
5060 5060 // We do this the hard way, by blocking the thread.
5061 5061 // Consider enforcing a minimum timeout value.
5062 5062 struct timespec abst;
5063 5063 compute_abstime(&abst, millis);
5064 5064
5065 5065 int ret = OS_TIMEOUT;
5066 5066 int status = pthread_mutex_lock(_mutex);
5067 5067 assert_status(status == 0, status, "mutex_lock");
5068 5068 guarantee (_nParked == 0, "invariant") ;
5069 5069 ++_nParked ;
5070 5070
5071 5071 // Object.wait(timo) will return because of
5072 5072 // (a) notification
5073 5073 // (b) timeout
5074 5074 // (c) thread.interrupt
5075 5075 //
5076 5076 // Thread.interrupt and object.notify{All} both call Event::set.
5077 5077 // That is, we treat thread.interrupt as a special case of notification.
5078 5078 // The underlying Solaris implementation, cond_timedwait, admits
5079 5079 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5080 5080 // JVM from making those visible to Java code. As such, we must
5081 5081 // filter out spurious wakeups. We assume all ETIME returns are valid.
5082 5082 //
5083 5083 // TODO: properly differentiate simultaneous notify+interrupt.
5084 5084 // In that case, we should propagate the notify to another waiter.
5085 5085
5086 5086 while (_Event < 0) {
5087 5087 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5088 5088 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5089 5089 pthread_cond_destroy (_cond);
5090 5090 pthread_cond_init (_cond, NULL) ;
5091 5091 }
5092 5092 assert_status(status == 0 || status == EINTR ||
5093 5093 status == ETIME || status == ETIMEDOUT,
5094 5094 status, "cond_timedwait");
5095 5095 if (!FilterSpuriousWakeups) break ; // previous semantics
5096 5096 if (status == ETIME || status == ETIMEDOUT) break ;
5097 5097 // We consume and ignore EINTR and spurious wakeups.
5098 5098 }
5099 5099 --_nParked ;
5100 5100 if (_Event >= 0) {
5101 5101 ret = OS_OK;
5102 5102 }
5103 5103 _Event = 0 ;
5104 5104 status = pthread_mutex_unlock(_mutex);
5105 5105 assert_status(status == 0, status, "mutex_unlock");
5106 5106 assert (_nParked == 0, "invariant") ;
5107 5107 return ret;
5108 5108 }
5109 5109
5110 5110 void os::PlatformEvent::unpark() {
5111 5111 int v, AnyWaiters ;
5112 5112 for (;;) {
5113 5113 v = _Event ;
5114 5114 if (v > 0) {
5115 5115 // The LD of _Event could have reordered or be satisfied
5116 5116 // by a read-aside from this processor's write buffer.
5117 5117 // To avoid problems execute a barrier and then
5118 5118 // ratify the value.
5119 5119 OrderAccess::fence() ;
5120 5120 if (_Event == v) return ;
5121 5121 continue ;
5122 5122 }
5123 5123 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5124 5124 }
5125 5125 if (v < 0) {
5126 5126 // Wait for the thread associated with the event to vacate
5127 5127 int status = pthread_mutex_lock(_mutex);
5128 5128 assert_status(status == 0, status, "mutex_lock");
5129 5129 AnyWaiters = _nParked ;
5130 5130 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5131 5131 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5132 5132 AnyWaiters = 0 ;
5133 5133 pthread_cond_signal (_cond);
5134 5134 }
5135 5135 status = pthread_mutex_unlock(_mutex);
5136 5136 assert_status(status == 0, status, "mutex_unlock");
5137 5137 if (AnyWaiters != 0) {
5138 5138 status = pthread_cond_signal(_cond);
5139 5139 assert_status(status == 0, status, "cond_signal");
5140 5140 }
5141 5141 }
5142 5142
5143 5143 // Note that we signal() _after dropping the lock for "immortal" Events.
5144 5144 // This is safe and avoids a common class of futile wakeups. In rare
5145 5145 // circumstances this can cause a thread to return prematurely from
5146 5146 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5147 5147 // simply re-test the condition and re-park itself.
5148 5148 }
5149 5149
5150 5150
5151 5151 // JSR166
5152 5152 // -------------------------------------------------------
5153 5153
5154 5154 /*
5155 5155 * The solaris and linux implementations of park/unpark are fairly
5156 5156 * conservative for now, but can be improved. They currently use a
5157 5157 * mutex/condvar pair, plus a a count.
5158 5158 * Park decrements count if > 0, else does a condvar wait. Unpark
5159 5159 * sets count to 1 and signals condvar. Only one thread ever waits
5160 5160 * on the condvar. Contention seen when trying to park implies that someone
5161 5161 * is unparking you, so don't wait. And spurious returns are fine, so there
5162 5162 * is no need to track notifications.
5163 5163 */
5164 5164
5165 5165 #define MAX_SECS 100000000
5166 5166 /*
5167 5167 * This code is common to linux and solaris and will be moved to a
5168 5168 * common place in dolphin.
5169 5169 *
5170 5170 * The passed in time value is either a relative time in nanoseconds
5171 5171 * or an absolute time in milliseconds. Either way it has to be unpacked
5172 5172 * into suitable seconds and nanoseconds components and stored in the
5173 5173 * given timespec structure.
5174 5174 * Given time is a 64-bit value and the time_t used in the timespec is only
5175 5175 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5176 5176 * overflow if times way in the future are given. Further on Solaris versions
5177 5177 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5178 5178 * number of seconds, in abstime, is less than current_time + 100,000,000.
5179 5179 * As it will be 28 years before "now + 100000000" will overflow we can
5180 5180 * ignore overflow and just impose a hard-limit on seconds using the value
5181 5181 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5182 5182 * years from "now".
5183 5183 */
5184 5184
5185 5185 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5186 5186 assert (time > 0, "convertTime");
5187 5187
5188 5188 struct timeval now;
5189 5189 int status = gettimeofday(&now, NULL);
5190 5190 assert(status == 0, "gettimeofday");
5191 5191
5192 5192 time_t max_secs = now.tv_sec + MAX_SECS;
5193 5193
5194 5194 if (isAbsolute) {
5195 5195 jlong secs = time / 1000;
5196 5196 if (secs > max_secs) {
5197 5197 absTime->tv_sec = max_secs;
5198 5198 }
5199 5199 else {
5200 5200 absTime->tv_sec = secs;
5201 5201 }
5202 5202 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5203 5203 }
5204 5204 else {
5205 5205 jlong secs = time / NANOSECS_PER_SEC;
5206 5206 if (secs >= MAX_SECS) {
5207 5207 absTime->tv_sec = max_secs;
5208 5208 absTime->tv_nsec = 0;
5209 5209 }
5210 5210 else {
5211 5211 absTime->tv_sec = now.tv_sec + secs;
5212 5212 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5213 5213 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5214 5214 absTime->tv_nsec -= NANOSECS_PER_SEC;
5215 5215 ++absTime->tv_sec; // note: this must be <= max_secs
5216 5216 }
5217 5217 }
5218 5218 }
5219 5219 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5220 5220 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5221 5221 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5222 5222 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5223 5223 }
5224 5224
5225 5225 void Parker::park(bool isAbsolute, jlong time) {
5226 5226 // Optional fast-path check:
5227 5227 // Return immediately if a permit is available.
5228 5228 if (_counter > 0) {
5229 5229 _counter = 0 ;
5230 5230 OrderAccess::fence();
5231 5231 return ;
5232 5232 }
5233 5233
5234 5234 Thread* thread = Thread::current();
5235 5235 assert(thread->is_Java_thread(), "Must be JavaThread");
5236 5236 JavaThread *jt = (JavaThread *)thread;
5237 5237
5238 5238 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5239 5239 // Check interrupt before trying to wait
5240 5240 if (Thread::is_interrupted(thread, false)) {
5241 5241 return;
5242 5242 }
5243 5243
5244 5244 // Next, demultiplex/decode time arguments
5245 5245 timespec absTime;
5246 5246 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5247 5247 return;
5248 5248 }
5249 5249 if (time > 0) {
5250 5250 unpackTime(&absTime, isAbsolute, time);
5251 5251 }
5252 5252
5253 5253
5254 5254 // Enter safepoint region
5255 5255 // Beware of deadlocks such as 6317397.
5256 5256 // The per-thread Parker:: mutex is a classic leaf-lock.
5257 5257 // In particular a thread must never block on the Threads_lock while
5258 5258 // holding the Parker:: mutex. If safepoints are pending both the
5259 5259 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5260 5260 ThreadBlockInVM tbivm(jt);
5261 5261
5262 5262 // Don't wait if cannot get lock since interference arises from
5263 5263 // unblocking. Also. check interrupt before trying wait
5264 5264 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5265 5265 return;
5266 5266 }
5267 5267
5268 5268 int status ;
5269 5269 if (_counter > 0) { // no wait needed
5270 5270 _counter = 0;
5271 5271 status = pthread_mutex_unlock(_mutex);
5272 5272 assert (status == 0, "invariant") ;
5273 5273 OrderAccess::fence();
5274 5274 return;
5275 5275 }
5276 5276
5277 5277 #ifdef ASSERT
5278 5278 // Don't catch signals while blocked; let the running threads have the signals.
5279 5279 // (This allows a debugger to break into the running thread.)
5280 5280 sigset_t oldsigs;
5281 5281 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5282 5282 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5283 5283 #endif
5284 5284
5285 5285 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5286 5286 jt->set_suspend_equivalent();
5287 5287 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5288 5288
5289 5289 if (time == 0) {
5290 5290 status = pthread_cond_wait (_cond, _mutex) ;
5291 5291 } else {
5292 5292 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5293 5293 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5294 5294 pthread_cond_destroy (_cond) ;
5295 5295 pthread_cond_init (_cond, NULL);
5296 5296 }
5297 5297 }
5298 5298 assert_status(status == 0 || status == EINTR ||
5299 5299 status == ETIME || status == ETIMEDOUT,
5300 5300 status, "cond_timedwait");
5301 5301
5302 5302 #ifdef ASSERT
5303 5303 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5304 5304 #endif
5305 5305
5306 5306 _counter = 0 ;
5307 5307 status = pthread_mutex_unlock(_mutex) ;
5308 5308 assert_status(status == 0, status, "invariant") ;
5309 5309 // If externally suspended while waiting, re-suspend
5310 5310 if (jt->handle_special_suspend_equivalent_condition()) {
5311 5311 jt->java_suspend_self();
5312 5312 }
5313 5313
5314 5314 OrderAccess::fence();
5315 5315 }
5316 5316
5317 5317 void Parker::unpark() {
5318 5318 int s, status ;
5319 5319 status = pthread_mutex_lock(_mutex);
5320 5320 assert (status == 0, "invariant") ;
5321 5321 s = _counter;
5322 5322 _counter = 1;
5323 5323 if (s < 1) {
5324 5324 if (WorkAroundNPTLTimedWaitHang) {
5325 5325 status = pthread_cond_signal (_cond) ;
5326 5326 assert (status == 0, "invariant") ;
5327 5327 status = pthread_mutex_unlock(_mutex);
5328 5328 assert (status == 0, "invariant") ;
5329 5329 } else {
5330 5330 status = pthread_mutex_unlock(_mutex);
5331 5331 assert (status == 0, "invariant") ;
5332 5332 status = pthread_cond_signal (_cond) ;
5333 5333 assert (status == 0, "invariant") ;
5334 5334 }
5335 5335 } else {
5336 5336 pthread_mutex_unlock(_mutex);
5337 5337 assert (status == 0, "invariant") ;
5338 5338 }
5339 5339 }
5340 5340
5341 5341
5342 5342 extern char** environ;
5343 5343
5344 5344 #ifndef __NR_fork
5345 5345 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5346 5346 #endif
5347 5347
5348 5348 #ifndef __NR_execve
5349 5349 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5350 5350 #endif
5351 5351
5352 5352 // Run the specified command in a separate process. Return its exit value,
5353 5353 // or -1 on failure (e.g. can't fork a new process).
5354 5354 // Unlike system(), this function can be called from signal handler. It
5355 5355 // doesn't block SIGINT et al.
5356 5356 int os::fork_and_exec(char* cmd) {
5357 5357 const char * argv[4] = {"sh", "-c", cmd, NULL};
5358 5358
5359 5359 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5360 5360 // pthread_atfork handlers and reset pthread library. All we need is a
5361 5361 // separate process to execve. Make a direct syscall to fork process.
5362 5362 // On IA64 there's no fork syscall, we have to use fork() and hope for
5363 5363 // the best...
5364 5364 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5365 5365 IA64_ONLY(fork();)
5366 5366
5367 5367 if (pid < 0) {
5368 5368 // fork failed
5369 5369 return -1;
5370 5370
5371 5371 } else if (pid == 0) {
5372 5372 // child process
5373 5373
5374 5374 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5375 5375 // first to kill every thread on the thread list. Because this list is
5376 5376 // not reset by fork() (see notes above), execve() will instead kill
5377 5377 // every thread in the parent process. We know this is the only thread
5378 5378 // in the new process, so make a system call directly.
5379 5379 // IA64 should use normal execve() from glibc to match the glibc fork()
5380 5380 // above.
5381 5381 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5382 5382 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5383 5383
5384 5384 // execve failed
5385 5385 _exit(-1);
5386 5386
5387 5387 } else {
5388 5388 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5389 5389 // care about the actual exit code, for now.
5390 5390
5391 5391 int status;
5392 5392
5393 5393 // Wait for the child process to exit. This returns immediately if
5394 5394 // the child has already exited. */
5395 5395 while (waitpid(pid, &status, 0) < 0) {
5396 5396 switch (errno) {
5397 5397 case ECHILD: return 0;
5398 5398 case EINTR: break;
5399 5399 default: return -1;
5400 5400 }
5401 5401 }
5402 5402
5403 5403 if (WIFEXITED(status)) {
5404 5404 // The child exited normally; get its exit code.
5405 5405 return WEXITSTATUS(status);
5406 5406 } else if (WIFSIGNALED(status)) {
5407 5407 // The child exited because of a signal
5408 5408 // The best value to return is 0x80 + signal number,
5409 5409 // because that is what all Unix shells do, and because
5410 5410 // it allows callers to distinguish between process exit and
5411 5411 // process death by signal.
5412 5412 return 0x80 + WTERMSIG(status);
5413 5413 } else {
5414 5414 // Unknown exit code; pass it through
5415 5415 return status;
5416 5416 }
5417 5417 }
5418 5418 }
5419 5419
5420 5420 // is_headless_jre()
5421 5421 //
5422 5422 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5423 5423 // in order to report if we are running in a headless jre
5424 5424 //
5425 5425 // Since JDK8 xawt/libmawt.so was moved into the same directory
5426 5426 // as libawt.so, and renamed libawt_xawt.so
5427 5427 //
5428 5428 bool os::is_headless_jre() {
5429 5429 struct stat statbuf;
5430 5430 char buf[MAXPATHLEN];
5431 5431 char libmawtpath[MAXPATHLEN];
5432 5432 const char *xawtstr = "/xawt/libmawt.so";
5433 5433 const char *new_xawtstr = "/libawt_xawt.so";
5434 5434 char *p;
5435 5435
5436 5436 // Get path to libjvm.so
5437 5437 os::jvm_path(buf, sizeof(buf));
5438 5438
5439 5439 // Get rid of libjvm.so
5440 5440 p = strrchr(buf, '/');
5441 5441 if (p == NULL) return false;
5442 5442 else *p = '\0';
5443 5443
5444 5444 // Get rid of client or server
5445 5445 p = strrchr(buf, '/');
5446 5446 if (p == NULL) return false;
5447 5447 else *p = '\0';
5448 5448
5449 5449 // check xawt/libmawt.so
5450 5450 strcpy(libmawtpath, buf);
5451 5451 strcat(libmawtpath, xawtstr);
5452 5452 if (::stat(libmawtpath, &statbuf) == 0) return false;
5453 5453
5454 5454 // check libawt_xawt.so
5455 5455 strcpy(libmawtpath, buf);
5456 5456 strcat(libmawtpath, new_xawtstr);
5457 5457 if (::stat(libmawtpath, &statbuf) == 0) return false;
5458 5458
5459 5459 return true;
5460 5460 }
5461 5461
5462 5462
5463 5463 #ifdef JAVASE_EMBEDDED
5464 5464 //
5465 5465 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5466 5466 //
5467 5467 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5468 5468
5469 5469 // ctor
5470 5470 //
5471 5471 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5472 5472 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5473 5473 _fd = fd;
5474 5474
5475 5475 if (os::create_thread(this, os::os_thread)) {
5476 5476 _memnotify_thread = this;
5477 5477 os::set_priority(this, NearMaxPriority);
5478 5478 os::start_thread(this);
5479 5479 }
5480 5480 }
5481 5481
5482 5482 // Where all the work gets done
5483 5483 //
5484 5484 void MemNotifyThread::run() {
5485 5485 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5486 5486
5487 5487 // Set up the select arguments
5488 5488 fd_set rfds;
5489 5489 if (_fd != -1) {
5490 5490 FD_ZERO(&rfds);
5491 5491 FD_SET(_fd, &rfds);
5492 5492 }
5493 5493
5494 5494 // Now wait for the mem_notify device to wake up
5495 5495 while (1) {
5496 5496 // Wait for the mem_notify device to signal us..
5497 5497 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5498 5498 if (rc == -1) {
5499 5499 perror("select!\n");
5500 5500 break;
5501 5501 } else if (rc) {
5502 5502 //ssize_t free_before = os::available_memory();
5503 5503 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5504 5504
5505 5505 // The kernel is telling us there is not much memory left...
5506 5506 // try to do something about that
5507 5507
5508 5508 // If we are not already in a GC, try one.
5509 5509 if (!Universe::heap()->is_gc_active()) {
5510 5510 Universe::heap()->collect(GCCause::_allocation_failure);
5511 5511
5512 5512 //ssize_t free_after = os::available_memory();
5513 5513 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5514 5514 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5515 5515 }
5516 5516 // We might want to do something like the following if we find the GC's are not helping...
5517 5517 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5518 5518 }
5519 5519 }
5520 5520 }
5521 5521
5522 5522 //
5523 5523 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5524 5524 //
5525 5525 void MemNotifyThread::start() {
5526 5526 int fd;
5527 5527 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5528 5528 if (fd < 0) {
5529 5529 return;
5530 5530 }
5531 5531
5532 5532 if (memnotify_thread() == NULL) {
5533 5533 new MemNotifyThread(fd);
5534 5534 }
5535 5535 }
5536 5536 #endif // JAVASE_EMBEDDED
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