1 /* 2 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "compiler/disassembler.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "memory/allocation.inline.hpp" 36 #include "memory/filemap.hpp" 37 #include "mutex_linux.inline.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_linux.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "prims/jniFastGetField.hpp" 42 #include "prims/jvm.h" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/atomic.inline.hpp" 46 #include "runtime/extendedPC.hpp" 47 #include "runtime/globals.hpp" 48 #include "runtime/interfaceSupport.hpp" 49 #include "runtime/init.hpp" 50 #include "runtime/java.hpp" 51 #include "runtime/javaCalls.hpp" 52 #include "runtime/mutexLocker.hpp" 53 #include "runtime/objectMonitor.hpp" 54 #include "runtime/orderAccess.inline.hpp" 55 #include "runtime/osThread.hpp" 56 #include "runtime/perfMemory.hpp" 57 #include "runtime/sharedRuntime.hpp" 58 #include "runtime/statSampler.hpp" 59 #include "runtime/stubRoutines.hpp" 60 #include "runtime/thread.inline.hpp" 61 #include "runtime/threadCritical.hpp" 62 #include "runtime/timer.hpp" 63 #include "semaphore_posix.hpp" 64 #include "services/attachListener.hpp" 65 #include "services/memTracker.hpp" 66 #include "services/runtimeService.hpp" 67 #include "utilities/decoder.hpp" 68 #include "utilities/defaultStream.hpp" 69 #include "utilities/events.hpp" 70 #include "utilities/elfFile.hpp" 71 #include "utilities/growableArray.hpp" 72 #include "utilities/macros.hpp" 73 #include "utilities/vmError.hpp" 74 75 // put OS-includes here 76 # include <sys/types.h> 77 # include <sys/mman.h> 78 # include <sys/stat.h> 79 # include <sys/select.h> 80 # include <pthread.h> 81 # include <signal.h> 82 # include <errno.h> 83 # include <dlfcn.h> 84 # include <stdio.h> 85 # include <unistd.h> 86 # include <sys/resource.h> 87 # include <pthread.h> 88 # include <sys/stat.h> 89 # include <sys/time.h> 90 # include <sys/times.h> 91 # include <sys/utsname.h> 92 # include <sys/socket.h> 93 # include <sys/wait.h> 94 # include <pwd.h> 95 # include <poll.h> 96 # include <semaphore.h> 97 # include <fcntl.h> 98 # include <string.h> 99 # include <syscall.h> 100 # include <sys/sysinfo.h> 101 # include <gnu/libc-version.h> 102 # include <sys/ipc.h> 103 # include <sys/shm.h> 104 # include <link.h> 105 # include <stdint.h> 106 # include <inttypes.h> 107 # include <sys/ioctl.h> 108 109 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 110 // getrusage() is prepared to handle the associated failure. 111 #ifndef RUSAGE_THREAD 112 #define RUSAGE_THREAD (1) /* only the calling thread */ 113 #endif 114 115 #define MAX_PATH (2 * K) 116 117 #define MAX_SECS 100000000 118 119 // for timer info max values which include all bits 120 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 121 122 #define LARGEPAGES_BIT (1 << 6) 123 //////////////////////////////////////////////////////////////////////////////// 124 // global variables 125 julong os::Linux::_physical_memory = 0; 126 127 address os::Linux::_initial_thread_stack_bottom = NULL; 128 uintptr_t os::Linux::_initial_thread_stack_size = 0; 129 130 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 131 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 132 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 133 Mutex* os::Linux::_createThread_lock = NULL; 134 pthread_t os::Linux::_main_thread; 135 int os::Linux::_page_size = -1; 136 const int os::Linux::_vm_default_page_size = (8 * K); 137 bool os::Linux::_supports_fast_thread_cpu_time = false; 138 const char * os::Linux::_glibc_version = NULL; 139 const char * os::Linux::_libpthread_version = NULL; 140 pthread_condattr_t os::Linux::_condattr[1]; 141 142 static jlong initial_time_count=0; 143 144 static int clock_tics_per_sec = 100; 145 146 // For diagnostics to print a message once. see run_periodic_checks 147 static sigset_t check_signal_done; 148 static bool check_signals = true; 149 150 // Signal number used to suspend/resume a thread 151 152 // do not use any signal number less than SIGSEGV, see 4355769 153 static int SR_signum = SIGUSR2; 154 sigset_t SR_sigset; 155 156 // Declarations 157 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 158 159 // utility functions 160 161 static int SR_initialize(); 162 163 julong os::available_memory() { 164 return Linux::available_memory(); 165 } 166 167 julong os::Linux::available_memory() { 168 // values in struct sysinfo are "unsigned long" 169 struct sysinfo si; 170 sysinfo(&si); 171 172 return (julong)si.freeram * si.mem_unit; 173 } 174 175 julong os::physical_memory() { 176 return Linux::physical_memory(); 177 } 178 179 // Return true if user is running as root. 180 181 bool os::have_special_privileges() { 182 static bool init = false; 183 static bool privileges = false; 184 if (!init) { 185 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 186 init = true; 187 } 188 return privileges; 189 } 190 191 192 #ifndef SYS_gettid 193 // i386: 224, ia64: 1105, amd64: 186, sparc 143 194 #ifdef __ia64__ 195 #define SYS_gettid 1105 196 #else 197 #ifdef __i386__ 198 #define SYS_gettid 224 199 #else 200 #ifdef __amd64__ 201 #define SYS_gettid 186 202 #else 203 #ifdef __sparc__ 204 #define SYS_gettid 143 205 #else 206 #error define gettid for the arch 207 #endif 208 #endif 209 #endif 210 #endif 211 #endif 212 213 // Cpu architecture string 214 static char cpu_arch[] = HOTSPOT_LIB_ARCH; 215 216 217 // pid_t gettid() 218 // 219 // Returns the kernel thread id of the currently running thread. Kernel 220 // thread id is used to access /proc. 221 pid_t os::Linux::gettid() { 222 int rslt = syscall(SYS_gettid); 223 assert(rslt != -1, "must be."); // old linuxthreads implementation? 224 return (pid_t)rslt; 225 } 226 227 // Most versions of linux have a bug where the number of processors are 228 // determined by looking at the /proc file system. In a chroot environment, 229 // the system call returns 1. This causes the VM to act as if it is 230 // a single processor and elide locking (see is_MP() call). 231 static bool unsafe_chroot_detected = false; 232 static const char *unstable_chroot_error = "/proc file system not found.\n" 233 "Java may be unstable running multithreaded in a chroot " 234 "environment on Linux when /proc filesystem is not mounted."; 235 236 void os::Linux::initialize_system_info() { 237 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 238 if (processor_count() == 1) { 239 pid_t pid = os::Linux::gettid(); 240 char fname[32]; 241 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 242 FILE *fp = fopen(fname, "r"); 243 if (fp == NULL) { 244 unsafe_chroot_detected = true; 245 } else { 246 fclose(fp); 247 } 248 } 249 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 250 assert(processor_count() > 0, "linux error"); 251 } 252 253 void os::init_system_properties_values() { 254 // The next steps are taken in the product version: 255 // 256 // Obtain the JAVA_HOME value from the location of libjvm.so. 257 // This library should be located at: 258 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 259 // 260 // If "/jre/lib/" appears at the right place in the path, then we 261 // assume libjvm.so is installed in a JDK and we use this path. 262 // 263 // Otherwise exit with message: "Could not create the Java virtual machine." 264 // 265 // The following extra steps are taken in the debugging version: 266 // 267 // If "/jre/lib/" does NOT appear at the right place in the path 268 // instead of exit check for $JAVA_HOME environment variable. 269 // 270 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 271 // then we append a fake suffix "hotspot/libjvm.so" to this path so 272 // it looks like libjvm.so is installed there 273 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 274 // 275 // Otherwise exit. 276 // 277 // Important note: if the location of libjvm.so changes this 278 // code needs to be changed accordingly. 279 280 // See ld(1): 281 // The linker uses the following search paths to locate required 282 // shared libraries: 283 // 1: ... 284 // ... 285 // 7: The default directories, normally /lib and /usr/lib. 286 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 287 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 288 #else 289 #define DEFAULT_LIBPATH "/lib:/usr/lib" 290 #endif 291 292 // Base path of extensions installed on the system. 293 #define SYS_EXT_DIR "/usr/java/packages" 294 #define EXTENSIONS_DIR "/lib/ext" 295 296 // Buffer that fits several sprintfs. 297 // Note that the space for the colon and the trailing null are provided 298 // by the nulls included by the sizeof operator. 299 const size_t bufsize = 300 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 301 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 302 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 303 304 // sysclasspath, java_home, dll_dir 305 { 306 char *pslash; 307 os::jvm_path(buf, bufsize); 308 309 // Found the full path to libjvm.so. 310 // Now cut the path to <java_home>/jre if we can. 311 pslash = strrchr(buf, '/'); 312 if (pslash != NULL) { 313 *pslash = '\0'; // Get rid of /libjvm.so. 314 } 315 pslash = strrchr(buf, '/'); 316 if (pslash != NULL) { 317 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 318 } 319 Arguments::set_dll_dir(buf); 320 321 if (pslash != NULL) { 322 pslash = strrchr(buf, '/'); 323 if (pslash != NULL) { 324 *pslash = '\0'; // Get rid of /<arch>. 325 pslash = strrchr(buf, '/'); 326 if (pslash != NULL) { 327 *pslash = '\0'; // Get rid of /lib. 328 } 329 } 330 } 331 Arguments::set_java_home(buf); 332 set_boot_path('/', ':'); 333 } 334 335 // Where to look for native libraries. 336 // 337 // Note: Due to a legacy implementation, most of the library path 338 // is set in the launcher. This was to accomodate linking restrictions 339 // on legacy Linux implementations (which are no longer supported). 340 // Eventually, all the library path setting will be done here. 341 // 342 // However, to prevent the proliferation of improperly built native 343 // libraries, the new path component /usr/java/packages is added here. 344 // Eventually, all the library path setting will be done here. 345 { 346 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 347 // should always exist (until the legacy problem cited above is 348 // addressed). 349 const char *v = ::getenv("LD_LIBRARY_PATH"); 350 const char *v_colon = ":"; 351 if (v == NULL) { v = ""; v_colon = ""; } 352 // That's +1 for the colon and +1 for the trailing '\0'. 353 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 354 strlen(v) + 1 + 355 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 356 mtInternal); 357 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 358 Arguments::set_library_path(ld_library_path); 359 FREE_C_HEAP_ARRAY(char, ld_library_path); 360 } 361 362 // Extensions directories. 363 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 364 Arguments::set_ext_dirs(buf); 365 366 FREE_C_HEAP_ARRAY(char, buf); 367 368 #undef DEFAULT_LIBPATH 369 #undef SYS_EXT_DIR 370 #undef EXTENSIONS_DIR 371 } 372 373 //////////////////////////////////////////////////////////////////////////////// 374 // breakpoint support 375 376 void os::breakpoint() { 377 BREAKPOINT; 378 } 379 380 extern "C" void breakpoint() { 381 // use debugger to set breakpoint here 382 } 383 384 //////////////////////////////////////////////////////////////////////////////// 385 // signal support 386 387 debug_only(static bool signal_sets_initialized = false); 388 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 389 390 bool os::Linux::is_sig_ignored(int sig) { 391 struct sigaction oact; 392 sigaction(sig, (struct sigaction*)NULL, &oact); 393 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 394 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 395 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 396 return true; 397 } else { 398 return false; 399 } 400 } 401 402 void os::Linux::signal_sets_init() { 403 // Should also have an assertion stating we are still single-threaded. 404 assert(!signal_sets_initialized, "Already initialized"); 405 // Fill in signals that are necessarily unblocked for all threads in 406 // the VM. Currently, we unblock the following signals: 407 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 408 // by -Xrs (=ReduceSignalUsage)); 409 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 410 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 411 // the dispositions or masks wrt these signals. 412 // Programs embedding the VM that want to use the above signals for their 413 // own purposes must, at this time, use the "-Xrs" option to prevent 414 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 415 // (See bug 4345157, and other related bugs). 416 // In reality, though, unblocking these signals is really a nop, since 417 // these signals are not blocked by default. 418 sigemptyset(&unblocked_sigs); 419 sigemptyset(&allowdebug_blocked_sigs); 420 sigaddset(&unblocked_sigs, SIGILL); 421 sigaddset(&unblocked_sigs, SIGSEGV); 422 sigaddset(&unblocked_sigs, SIGBUS); 423 sigaddset(&unblocked_sigs, SIGFPE); 424 #if defined(PPC64) 425 sigaddset(&unblocked_sigs, SIGTRAP); 426 #endif 427 sigaddset(&unblocked_sigs, SR_signum); 428 429 if (!ReduceSignalUsage) { 430 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 431 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 432 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 433 } 434 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 435 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 436 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 437 } 438 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 439 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 441 } 442 } 443 // Fill in signals that are blocked by all but the VM thread. 444 sigemptyset(&vm_sigs); 445 if (!ReduceSignalUsage) { 446 sigaddset(&vm_sigs, BREAK_SIGNAL); 447 } 448 debug_only(signal_sets_initialized = true); 449 450 } 451 452 // These are signals that are unblocked while a thread is running Java. 453 // (For some reason, they get blocked by default.) 454 sigset_t* os::Linux::unblocked_signals() { 455 assert(signal_sets_initialized, "Not initialized"); 456 return &unblocked_sigs; 457 } 458 459 // These are the signals that are blocked while a (non-VM) thread is 460 // running Java. Only the VM thread handles these signals. 461 sigset_t* os::Linux::vm_signals() { 462 assert(signal_sets_initialized, "Not initialized"); 463 return &vm_sigs; 464 } 465 466 // These are signals that are blocked during cond_wait to allow debugger in 467 sigset_t* os::Linux::allowdebug_blocked_signals() { 468 assert(signal_sets_initialized, "Not initialized"); 469 return &allowdebug_blocked_sigs; 470 } 471 472 void os::Linux::hotspot_sigmask(Thread* thread) { 473 474 //Save caller's signal mask before setting VM signal mask 475 sigset_t caller_sigmask; 476 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 477 478 OSThread* osthread = thread->osthread(); 479 osthread->set_caller_sigmask(caller_sigmask); 480 481 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 482 483 if (!ReduceSignalUsage) { 484 if (thread->is_VM_thread()) { 485 // Only the VM thread handles BREAK_SIGNAL ... 486 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 487 } else { 488 // ... all other threads block BREAK_SIGNAL 489 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 490 } 491 } 492 } 493 494 ////////////////////////////////////////////////////////////////////////////// 495 // detecting pthread library 496 497 void os::Linux::libpthread_init() { 498 // Save glibc and pthread version strings. 499 #if !defined(_CS_GNU_LIBC_VERSION) || \ 500 !defined(_CS_GNU_LIBPTHREAD_VERSION) 501 #error "glibc too old (< 2.3.2)" 502 #endif 503 504 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 505 assert(n > 0, "cannot retrieve glibc version"); 506 char *str = (char *)malloc(n, mtInternal); 507 confstr(_CS_GNU_LIBC_VERSION, str, n); 508 os::Linux::set_glibc_version(str); 509 510 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 511 assert(n > 0, "cannot retrieve pthread version"); 512 str = (char *)malloc(n, mtInternal); 513 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 514 os::Linux::set_libpthread_version(str); 515 } 516 517 ///////////////////////////////////////////////////////////////////////////// 518 // thread stack expansion 519 520 // os::Linux::manually_expand_stack() takes care of expanding the thread 521 // stack. Note that this is normally not needed: pthread stacks allocate 522 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 523 // committed. Therefore it is not necessary to expand the stack manually. 524 // 525 // Manually expanding the stack was historically needed on LinuxThreads 526 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 527 // it is kept to deal with very rare corner cases: 528 // 529 // For one, user may run the VM on an own implementation of threads 530 // whose stacks are - like the old LinuxThreads - implemented using 531 // mmap(MAP_GROWSDOWN). 532 // 533 // Also, this coding may be needed if the VM is running on the primordial 534 // thread. Normally we avoid running on the primordial thread; however, 535 // user may still invoke the VM on the primordial thread. 536 // 537 // The following historical comment describes the details about running 538 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 539 540 541 // Force Linux kernel to expand current thread stack. If "bottom" is close 542 // to the stack guard, caller should block all signals. 543 // 544 // MAP_GROWSDOWN: 545 // A special mmap() flag that is used to implement thread stacks. It tells 546 // kernel that the memory region should extend downwards when needed. This 547 // allows early versions of LinuxThreads to only mmap the first few pages 548 // when creating a new thread. Linux kernel will automatically expand thread 549 // stack as needed (on page faults). 550 // 551 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 552 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 553 // region, it's hard to tell if the fault is due to a legitimate stack 554 // access or because of reading/writing non-exist memory (e.g. buffer 555 // overrun). As a rule, if the fault happens below current stack pointer, 556 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 557 // application (see Linux kernel fault.c). 558 // 559 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 560 // stack overflow detection. 561 // 562 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 563 // not use MAP_GROWSDOWN. 564 // 565 // To get around the problem and allow stack banging on Linux, we need to 566 // manually expand thread stack after receiving the SIGSEGV. 567 // 568 // There are two ways to expand thread stack to address "bottom", we used 569 // both of them in JVM before 1.5: 570 // 1. adjust stack pointer first so that it is below "bottom", and then 571 // touch "bottom" 572 // 2. mmap() the page in question 573 // 574 // Now alternate signal stack is gone, it's harder to use 2. For instance, 575 // if current sp is already near the lower end of page 101, and we need to 576 // call mmap() to map page 100, it is possible that part of the mmap() frame 577 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 578 // That will destroy the mmap() frame and cause VM to crash. 579 // 580 // The following code works by adjusting sp first, then accessing the "bottom" 581 // page to force a page fault. Linux kernel will then automatically expand the 582 // stack mapping. 583 // 584 // _expand_stack_to() assumes its frame size is less than page size, which 585 // should always be true if the function is not inlined. 586 587 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 588 #define NOINLINE 589 #else 590 #define NOINLINE __attribute__ ((noinline)) 591 #endif 592 593 static void _expand_stack_to(address bottom) NOINLINE; 594 595 static void _expand_stack_to(address bottom) { 596 address sp; 597 size_t size; 598 volatile char *p; 599 600 // Adjust bottom to point to the largest address within the same page, it 601 // gives us a one-page buffer if alloca() allocates slightly more memory. 602 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 603 bottom += os::Linux::page_size() - 1; 604 605 // sp might be slightly above current stack pointer; if that's the case, we 606 // will alloca() a little more space than necessary, which is OK. Don't use 607 // os::current_stack_pointer(), as its result can be slightly below current 608 // stack pointer, causing us to not alloca enough to reach "bottom". 609 sp = (address)&sp; 610 611 if (sp > bottom) { 612 size = sp - bottom; 613 p = (volatile char *)alloca(size); 614 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 615 p[0] = '\0'; 616 } 617 } 618 619 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 620 assert(t!=NULL, "just checking"); 621 assert(t->osthread()->expanding_stack(), "expand should be set"); 622 assert(t->stack_base() != NULL, "stack_base was not initialized"); 623 624 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 625 sigset_t mask_all, old_sigset; 626 sigfillset(&mask_all); 627 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 628 _expand_stack_to(addr); 629 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 630 return true; 631 } 632 return false; 633 } 634 635 ////////////////////////////////////////////////////////////////////////////// 636 // create new thread 637 638 // Thread start routine for all newly created threads 639 static void *java_start(Thread *thread) { 640 // Try to randomize the cache line index of hot stack frames. 641 // This helps when threads of the same stack traces evict each other's 642 // cache lines. The threads can be either from the same JVM instance, or 643 // from different JVM instances. The benefit is especially true for 644 // processors with hyperthreading technology. 645 static int counter = 0; 646 int pid = os::current_process_id(); 647 alloca(((pid ^ counter++) & 7) * 128); 648 649 ThreadLocalStorage::set_thread(thread); 650 651 OSThread* osthread = thread->osthread(); 652 Monitor* sync = osthread->startThread_lock(); 653 654 osthread->set_thread_id(os::current_thread_id()); 655 656 if (UseNUMA) { 657 int lgrp_id = os::numa_get_group_id(); 658 if (lgrp_id != -1) { 659 thread->set_lgrp_id(lgrp_id); 660 } 661 } 662 // initialize signal mask for this thread 663 os::Linux::hotspot_sigmask(thread); 664 665 // initialize floating point control register 666 os::Linux::init_thread_fpu_state(); 667 668 // handshaking with parent thread 669 { 670 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 671 672 // notify parent thread 673 osthread->set_state(INITIALIZED); 674 sync->notify_all(); 675 676 // wait until os::start_thread() 677 while (osthread->get_state() == INITIALIZED) { 678 sync->wait(Mutex::_no_safepoint_check_flag); 679 } 680 } 681 682 // call one more level start routine 683 thread->run(); 684 685 return 0; 686 } 687 688 bool os::create_thread(Thread* thread, ThreadType thr_type, 689 size_t stack_size) { 690 assert(thread->osthread() == NULL, "caller responsible"); 691 692 // Allocate the OSThread object 693 OSThread* osthread = new OSThread(NULL, NULL); 694 if (osthread == NULL) { 695 return false; 696 } 697 698 // set the correct thread state 699 osthread->set_thread_type(thr_type); 700 701 // Initial state is ALLOCATED but not INITIALIZED 702 osthread->set_state(ALLOCATED); 703 704 thread->set_osthread(osthread); 705 706 // init thread attributes 707 pthread_attr_t attr; 708 pthread_attr_init(&attr); 709 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 710 711 // stack size 712 // calculate stack size if it's not specified by caller 713 if (stack_size == 0) { 714 stack_size = os::Linux::default_stack_size(thr_type); 715 716 switch (thr_type) { 717 case os::java_thread: 718 // Java threads use ThreadStackSize which default value can be 719 // changed with the flag -Xss 720 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 721 stack_size = JavaThread::stack_size_at_create(); 722 break; 723 case os::compiler_thread: 724 if (CompilerThreadStackSize > 0) { 725 stack_size = (size_t)(CompilerThreadStackSize * K); 726 break; 727 } // else fall through: 728 // use VMThreadStackSize if CompilerThreadStackSize is not defined 729 case os::vm_thread: 730 case os::pgc_thread: 731 case os::cgc_thread: 732 case os::watcher_thread: 733 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 734 break; 735 } 736 } 737 738 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 739 pthread_attr_setstacksize(&attr, stack_size); 740 741 // glibc guard page 742 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 743 744 ThreadState state; 745 746 { 747 pthread_t tid; 748 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 749 750 pthread_attr_destroy(&attr); 751 752 if (ret != 0) { 753 if (PrintMiscellaneous && (Verbose || WizardMode)) { 754 perror("pthread_create()"); 755 } 756 // Need to clean up stuff we've allocated so far 757 thread->set_osthread(NULL); 758 delete osthread; 759 return false; 760 } 761 762 // Store pthread info into the OSThread 763 osthread->set_pthread_id(tid); 764 765 // Wait until child thread is either initialized or aborted 766 { 767 Monitor* sync_with_child = osthread->startThread_lock(); 768 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 769 while ((state = osthread->get_state()) == ALLOCATED) { 770 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 771 } 772 } 773 } 774 775 // Aborted due to thread limit being reached 776 if (state == ZOMBIE) { 777 thread->set_osthread(NULL); 778 delete osthread; 779 return false; 780 } 781 782 // The thread is returned suspended (in state INITIALIZED), 783 // and is started higher up in the call chain 784 assert(state == INITIALIZED, "race condition"); 785 return true; 786 } 787 788 ///////////////////////////////////////////////////////////////////////////// 789 // attach existing thread 790 791 // bootstrap the main thread 792 bool os::create_main_thread(JavaThread* thread) { 793 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 794 return create_attached_thread(thread); 795 } 796 797 bool os::create_attached_thread(JavaThread* thread) { 798 #ifdef ASSERT 799 thread->verify_not_published(); 800 #endif 801 802 // Allocate the OSThread object 803 OSThread* osthread = new OSThread(NULL, NULL); 804 805 if (osthread == NULL) { 806 return false; 807 } 808 809 // Store pthread info into the OSThread 810 osthread->set_thread_id(os::Linux::gettid()); 811 osthread->set_pthread_id(::pthread_self()); 812 813 // initialize floating point control register 814 os::Linux::init_thread_fpu_state(); 815 816 // Initial thread state is RUNNABLE 817 osthread->set_state(RUNNABLE); 818 819 thread->set_osthread(osthread); 820 821 if (UseNUMA) { 822 int lgrp_id = os::numa_get_group_id(); 823 if (lgrp_id != -1) { 824 thread->set_lgrp_id(lgrp_id); 825 } 826 } 827 828 if (os::Linux::is_initial_thread()) { 829 // If current thread is initial thread, its stack is mapped on demand, 830 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 831 // the entire stack region to avoid SEGV in stack banging. 832 // It is also useful to get around the heap-stack-gap problem on SuSE 833 // kernel (see 4821821 for details). We first expand stack to the top 834 // of yellow zone, then enable stack yellow zone (order is significant, 835 // enabling yellow zone first will crash JVM on SuSE Linux), so there 836 // is no gap between the last two virtual memory regions. 837 838 JavaThread *jt = (JavaThread *)thread; 839 address addr = jt->stack_yellow_zone_base(); 840 assert(addr != NULL, "initialization problem?"); 841 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 842 843 osthread->set_expanding_stack(); 844 os::Linux::manually_expand_stack(jt, addr); 845 osthread->clear_expanding_stack(); 846 } 847 848 // initialize signal mask for this thread 849 // and save the caller's signal mask 850 os::Linux::hotspot_sigmask(thread); 851 852 return true; 853 } 854 855 void os::pd_start_thread(Thread* thread) { 856 OSThread * osthread = thread->osthread(); 857 assert(osthread->get_state() != INITIALIZED, "just checking"); 858 Monitor* sync_with_child = osthread->startThread_lock(); 859 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 860 sync_with_child->notify(); 861 } 862 863 // Free Linux resources related to the OSThread 864 void os::free_thread(OSThread* osthread) { 865 assert(osthread != NULL, "osthread not set"); 866 867 if (Thread::current()->osthread() == osthread) { 868 // Restore caller's signal mask 869 sigset_t sigmask = osthread->caller_sigmask(); 870 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 871 } 872 873 delete osthread; 874 } 875 876 ////////////////////////////////////////////////////////////////////////////// 877 // thread local storage 878 879 // Restore the thread pointer if the destructor is called. This is in case 880 // someone from JNI code sets up a destructor with pthread_key_create to run 881 // detachCurrentThread on thread death. Unless we restore the thread pointer we 882 // will hang or crash. When detachCurrentThread is called the key will be set 883 // to null and we will not be called again. If detachCurrentThread is never 884 // called we could loop forever depending on the pthread implementation. 885 static void restore_thread_pointer(void* p) { 886 Thread* thread = (Thread*) p; 887 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread); 888 } 889 890 int os::allocate_thread_local_storage() { 891 pthread_key_t key; 892 int rslt = pthread_key_create(&key, restore_thread_pointer); 893 assert(rslt == 0, "cannot allocate thread local storage"); 894 return (int)key; 895 } 896 897 // Note: This is currently not used by VM, as we don't destroy TLS key 898 // on VM exit. 899 void os::free_thread_local_storage(int index) { 900 int rslt = pthread_key_delete((pthread_key_t)index); 901 assert(rslt == 0, "invalid index"); 902 } 903 904 void os::thread_local_storage_at_put(int index, void* value) { 905 int rslt = pthread_setspecific((pthread_key_t)index, value); 906 assert(rslt == 0, "pthread_setspecific failed"); 907 } 908 909 extern "C" Thread* get_thread() { 910 return ThreadLocalStorage::thread(); 911 } 912 913 ////////////////////////////////////////////////////////////////////////////// 914 // initial thread 915 916 // Check if current thread is the initial thread, similar to Solaris thr_main. 917 bool os::Linux::is_initial_thread(void) { 918 char dummy; 919 // If called before init complete, thread stack bottom will be null. 920 // Can be called if fatal error occurs before initialization. 921 if (initial_thread_stack_bottom() == NULL) return false; 922 assert(initial_thread_stack_bottom() != NULL && 923 initial_thread_stack_size() != 0, 924 "os::init did not locate initial thread's stack region"); 925 if ((address)&dummy >= initial_thread_stack_bottom() && 926 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 927 return true; 928 } else { 929 return false; 930 } 931 } 932 933 // Find the virtual memory area that contains addr 934 static bool find_vma(address addr, address* vma_low, address* vma_high) { 935 FILE *fp = fopen("/proc/self/maps", "r"); 936 if (fp) { 937 address low, high; 938 while (!feof(fp)) { 939 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 940 if (low <= addr && addr < high) { 941 if (vma_low) *vma_low = low; 942 if (vma_high) *vma_high = high; 943 fclose(fp); 944 return true; 945 } 946 } 947 for (;;) { 948 int ch = fgetc(fp); 949 if (ch == EOF || ch == (int)'\n') break; 950 } 951 } 952 fclose(fp); 953 } 954 return false; 955 } 956 957 // Locate initial thread stack. This special handling of initial thread stack 958 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 959 // bogus value for initial thread. 960 void os::Linux::capture_initial_stack(size_t max_size) { 961 // stack size is the easy part, get it from RLIMIT_STACK 962 size_t stack_size; 963 struct rlimit rlim; 964 getrlimit(RLIMIT_STACK, &rlim); 965 stack_size = rlim.rlim_cur; 966 967 // 6308388: a bug in ld.so will relocate its own .data section to the 968 // lower end of primordial stack; reduce ulimit -s value a little bit 969 // so we won't install guard page on ld.so's data section. 970 stack_size -= 2 * page_size(); 971 972 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 973 // 7.1, in both cases we will get 2G in return value. 974 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 975 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 976 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 977 // in case other parts in glibc still assumes 2M max stack size. 978 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 979 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 980 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 981 stack_size = 2 * K * K IA64_ONLY(*2); 982 } 983 // Try to figure out where the stack base (top) is. This is harder. 984 // 985 // When an application is started, glibc saves the initial stack pointer in 986 // a global variable "__libc_stack_end", which is then used by system 987 // libraries. __libc_stack_end should be pretty close to stack top. The 988 // variable is available since the very early days. However, because it is 989 // a private interface, it could disappear in the future. 990 // 991 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 992 // to __libc_stack_end, it is very close to stack top, but isn't the real 993 // stack top. Note that /proc may not exist if VM is running as a chroot 994 // program, so reading /proc/<pid>/stat could fail. Also the contents of 995 // /proc/<pid>/stat could change in the future (though unlikely). 996 // 997 // We try __libc_stack_end first. If that doesn't work, look for 998 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 999 // as a hint, which should work well in most cases. 1000 1001 uintptr_t stack_start; 1002 1003 // try __libc_stack_end first 1004 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1005 if (p && *p) { 1006 stack_start = *p; 1007 } else { 1008 // see if we can get the start_stack field from /proc/self/stat 1009 FILE *fp; 1010 int pid; 1011 char state; 1012 int ppid; 1013 int pgrp; 1014 int session; 1015 int nr; 1016 int tpgrp; 1017 unsigned long flags; 1018 unsigned long minflt; 1019 unsigned long cminflt; 1020 unsigned long majflt; 1021 unsigned long cmajflt; 1022 unsigned long utime; 1023 unsigned long stime; 1024 long cutime; 1025 long cstime; 1026 long prio; 1027 long nice; 1028 long junk; 1029 long it_real; 1030 uintptr_t start; 1031 uintptr_t vsize; 1032 intptr_t rss; 1033 uintptr_t rsslim; 1034 uintptr_t scodes; 1035 uintptr_t ecode; 1036 int i; 1037 1038 // Figure what the primordial thread stack base is. Code is inspired 1039 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1040 // followed by command name surrounded by parentheses, state, etc. 1041 char stat[2048]; 1042 int statlen; 1043 1044 fp = fopen("/proc/self/stat", "r"); 1045 if (fp) { 1046 statlen = fread(stat, 1, 2047, fp); 1047 stat[statlen] = '\0'; 1048 fclose(fp); 1049 1050 // Skip pid and the command string. Note that we could be dealing with 1051 // weird command names, e.g. user could decide to rename java launcher 1052 // to "java 1.4.2 :)", then the stat file would look like 1053 // 1234 (java 1.4.2 :)) R ... ... 1054 // We don't really need to know the command string, just find the last 1055 // occurrence of ")" and then start parsing from there. See bug 4726580. 1056 char * s = strrchr(stat, ')'); 1057 1058 i = 0; 1059 if (s) { 1060 // Skip blank chars 1061 do { s++; } while (s && isspace(*s)); 1062 1063 #define _UFM UINTX_FORMAT 1064 #define _DFM INTX_FORMAT 1065 1066 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1067 // 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 1068 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, 1069 &state, // 3 %c 1070 &ppid, // 4 %d 1071 &pgrp, // 5 %d 1072 &session, // 6 %d 1073 &nr, // 7 %d 1074 &tpgrp, // 8 %d 1075 &flags, // 9 %lu 1076 &minflt, // 10 %lu 1077 &cminflt, // 11 %lu 1078 &majflt, // 12 %lu 1079 &cmajflt, // 13 %lu 1080 &utime, // 14 %lu 1081 &stime, // 15 %lu 1082 &cutime, // 16 %ld 1083 &cstime, // 17 %ld 1084 &prio, // 18 %ld 1085 &nice, // 19 %ld 1086 &junk, // 20 %ld 1087 &it_real, // 21 %ld 1088 &start, // 22 UINTX_FORMAT 1089 &vsize, // 23 UINTX_FORMAT 1090 &rss, // 24 INTX_FORMAT 1091 &rsslim, // 25 UINTX_FORMAT 1092 &scodes, // 26 UINTX_FORMAT 1093 &ecode, // 27 UINTX_FORMAT 1094 &stack_start); // 28 UINTX_FORMAT 1095 } 1096 1097 #undef _UFM 1098 #undef _DFM 1099 1100 if (i != 28 - 2) { 1101 assert(false, "Bad conversion from /proc/self/stat"); 1102 // product mode - assume we are the initial thread, good luck in the 1103 // embedded case. 1104 warning("Can't detect initial thread stack location - bad conversion"); 1105 stack_start = (uintptr_t) &rlim; 1106 } 1107 } else { 1108 // For some reason we can't open /proc/self/stat (for example, running on 1109 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1110 // most cases, so don't abort: 1111 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1112 stack_start = (uintptr_t) &rlim; 1113 } 1114 } 1115 1116 // Now we have a pointer (stack_start) very close to the stack top, the 1117 // next thing to do is to figure out the exact location of stack top. We 1118 // can find out the virtual memory area that contains stack_start by 1119 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1120 // and its upper limit is the real stack top. (again, this would fail if 1121 // running inside chroot, because /proc may not exist.) 1122 1123 uintptr_t stack_top; 1124 address low, high; 1125 if (find_vma((address)stack_start, &low, &high)) { 1126 // success, "high" is the true stack top. (ignore "low", because initial 1127 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1128 stack_top = (uintptr_t)high; 1129 } else { 1130 // failed, likely because /proc/self/maps does not exist 1131 warning("Can't detect initial thread stack location - find_vma failed"); 1132 // best effort: stack_start is normally within a few pages below the real 1133 // stack top, use it as stack top, and reduce stack size so we won't put 1134 // guard page outside stack. 1135 stack_top = stack_start; 1136 stack_size -= 16 * page_size(); 1137 } 1138 1139 // stack_top could be partially down the page so align it 1140 stack_top = align_size_up(stack_top, page_size()); 1141 1142 if (max_size && stack_size > max_size) { 1143 _initial_thread_stack_size = max_size; 1144 } else { 1145 _initial_thread_stack_size = stack_size; 1146 } 1147 1148 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1149 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1150 } 1151 1152 //////////////////////////////////////////////////////////////////////////////// 1153 // time support 1154 1155 // Time since start-up in seconds to a fine granularity. 1156 // Used by VMSelfDestructTimer and the MemProfiler. 1157 double os::elapsedTime() { 1158 1159 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1160 } 1161 1162 jlong os::elapsed_counter() { 1163 return javaTimeNanos() - initial_time_count; 1164 } 1165 1166 jlong os::elapsed_frequency() { 1167 return NANOSECS_PER_SEC; // nanosecond resolution 1168 } 1169 1170 bool os::supports_vtime() { return true; } 1171 bool os::enable_vtime() { return false; } 1172 bool os::vtime_enabled() { return false; } 1173 1174 double os::elapsedVTime() { 1175 struct rusage usage; 1176 int retval = getrusage(RUSAGE_THREAD, &usage); 1177 if (retval == 0) { 1178 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1179 } else { 1180 // better than nothing, but not much 1181 return elapsedTime(); 1182 } 1183 } 1184 1185 jlong os::javaTimeMillis() { 1186 timeval time; 1187 int status = gettimeofday(&time, NULL); 1188 assert(status != -1, "linux error"); 1189 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1190 } 1191 1192 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1193 timeval time; 1194 int status = gettimeofday(&time, NULL); 1195 assert(status != -1, "linux error"); 1196 seconds = jlong(time.tv_sec); 1197 nanos = jlong(time.tv_usec) * 1000; 1198 } 1199 1200 1201 #ifndef CLOCK_MONOTONIC 1202 #define CLOCK_MONOTONIC (1) 1203 #endif 1204 1205 void os::Linux::clock_init() { 1206 // we do dlopen's in this particular order due to bug in linux 1207 // dynamical loader (see 6348968) leading to crash on exit 1208 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1209 if (handle == NULL) { 1210 handle = dlopen("librt.so", RTLD_LAZY); 1211 } 1212 1213 if (handle) { 1214 int (*clock_getres_func)(clockid_t, struct timespec*) = 1215 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1216 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1217 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1218 if (clock_getres_func && clock_gettime_func) { 1219 // See if monotonic clock is supported by the kernel. Note that some 1220 // early implementations simply return kernel jiffies (updated every 1221 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1222 // for nano time (though the monotonic property is still nice to have). 1223 // It's fixed in newer kernels, however clock_getres() still returns 1224 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1225 // resolution for now. Hopefully as people move to new kernels, this 1226 // won't be a problem. 1227 struct timespec res; 1228 struct timespec tp; 1229 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1230 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1231 // yes, monotonic clock is supported 1232 _clock_gettime = clock_gettime_func; 1233 return; 1234 } else { 1235 // close librt if there is no monotonic clock 1236 dlclose(handle); 1237 } 1238 } 1239 } 1240 warning("No monotonic clock was available - timed services may " \ 1241 "be adversely affected if the time-of-day clock changes"); 1242 } 1243 1244 #ifndef SYS_clock_getres 1245 #if defined(IA32) || defined(AMD64) 1246 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1247 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1248 #else 1249 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1250 #define sys_clock_getres(x,y) -1 1251 #endif 1252 #else 1253 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1254 #endif 1255 1256 void os::Linux::fast_thread_clock_init() { 1257 if (!UseLinuxPosixThreadCPUClocks) { 1258 return; 1259 } 1260 clockid_t clockid; 1261 struct timespec tp; 1262 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1263 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1264 1265 // Switch to using fast clocks for thread cpu time if 1266 // the sys_clock_getres() returns 0 error code. 1267 // Note, that some kernels may support the current thread 1268 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1269 // returned by the pthread_getcpuclockid(). 1270 // If the fast Posix clocks are supported then the sys_clock_getres() 1271 // must return at least tp.tv_sec == 0 which means a resolution 1272 // better than 1 sec. This is extra check for reliability. 1273 1274 if (pthread_getcpuclockid_func && 1275 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1276 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1277 _supports_fast_thread_cpu_time = true; 1278 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1279 } 1280 } 1281 1282 jlong os::javaTimeNanos() { 1283 if (os::supports_monotonic_clock()) { 1284 struct timespec tp; 1285 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1286 assert(status == 0, "gettime error"); 1287 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1288 return result; 1289 } else { 1290 timeval time; 1291 int status = gettimeofday(&time, NULL); 1292 assert(status != -1, "linux error"); 1293 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1294 return 1000 * usecs; 1295 } 1296 } 1297 1298 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1299 if (os::supports_monotonic_clock()) { 1300 info_ptr->max_value = ALL_64_BITS; 1301 1302 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1303 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1304 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1305 } else { 1306 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1307 info_ptr->max_value = ALL_64_BITS; 1308 1309 // gettimeofday is a real time clock so it skips 1310 info_ptr->may_skip_backward = true; 1311 info_ptr->may_skip_forward = true; 1312 } 1313 1314 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1315 } 1316 1317 // Return the real, user, and system times in seconds from an 1318 // arbitrary fixed point in the past. 1319 bool os::getTimesSecs(double* process_real_time, 1320 double* process_user_time, 1321 double* process_system_time) { 1322 struct tms ticks; 1323 clock_t real_ticks = times(&ticks); 1324 1325 if (real_ticks == (clock_t) (-1)) { 1326 return false; 1327 } else { 1328 double ticks_per_second = (double) clock_tics_per_sec; 1329 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1330 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1331 *process_real_time = ((double) real_ticks) / ticks_per_second; 1332 1333 return true; 1334 } 1335 } 1336 1337 1338 char * os::local_time_string(char *buf, size_t buflen) { 1339 struct tm t; 1340 time_t long_time; 1341 time(&long_time); 1342 localtime_r(&long_time, &t); 1343 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1344 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1345 t.tm_hour, t.tm_min, t.tm_sec); 1346 return buf; 1347 } 1348 1349 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1350 return localtime_r(clock, res); 1351 } 1352 1353 //////////////////////////////////////////////////////////////////////////////// 1354 // runtime exit support 1355 1356 // Note: os::shutdown() might be called very early during initialization, or 1357 // called from signal handler. Before adding something to os::shutdown(), make 1358 // sure it is async-safe and can handle partially initialized VM. 1359 void os::shutdown() { 1360 1361 // allow PerfMemory to attempt cleanup of any persistent resources 1362 perfMemory_exit(); 1363 1364 // needs to remove object in file system 1365 AttachListener::abort(); 1366 1367 // flush buffered output, finish log files 1368 ostream_abort(); 1369 1370 // Check for abort hook 1371 abort_hook_t abort_hook = Arguments::abort_hook(); 1372 if (abort_hook != NULL) { 1373 abort_hook(); 1374 } 1375 1376 } 1377 1378 // Note: os::abort() might be called very early during initialization, or 1379 // called from signal handler. Before adding something to os::abort(), make 1380 // sure it is async-safe and can handle partially initialized VM. 1381 void os::abort(bool dump_core, void* siginfo, void* context) { 1382 os::shutdown(); 1383 if (dump_core) { 1384 #ifndef PRODUCT 1385 fdStream out(defaultStream::output_fd()); 1386 out.print_raw("Current thread is "); 1387 char buf[16]; 1388 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1389 out.print_raw_cr(buf); 1390 out.print_raw_cr("Dumping core ..."); 1391 #endif 1392 ::abort(); // dump core 1393 } 1394 1395 ::exit(1); 1396 } 1397 1398 // Die immediately, no exit hook, no abort hook, no cleanup. 1399 void os::die() { 1400 ::abort(); 1401 } 1402 1403 1404 // This method is a copy of JDK's sysGetLastErrorString 1405 // from src/solaris/hpi/src/system_md.c 1406 1407 size_t os::lasterror(char *buf, size_t len) { 1408 if (errno == 0) return 0; 1409 1410 const char *s = ::strerror(errno); 1411 size_t n = ::strlen(s); 1412 if (n >= len) { 1413 n = len - 1; 1414 } 1415 ::strncpy(buf, s, n); 1416 buf[n] = '\0'; 1417 return n; 1418 } 1419 1420 // thread_id is kernel thread id (similar to Solaris LWP id) 1421 intx os::current_thread_id() { return os::Linux::gettid(); } 1422 int os::current_process_id() { 1423 return ::getpid(); 1424 } 1425 1426 // DLL functions 1427 1428 const char* os::dll_file_extension() { return ".so"; } 1429 1430 // This must be hard coded because it's the system's temporary 1431 // directory not the java application's temp directory, ala java.io.tmpdir. 1432 const char* os::get_temp_directory() { return "/tmp"; } 1433 1434 static bool file_exists(const char* filename) { 1435 struct stat statbuf; 1436 if (filename == NULL || strlen(filename) == 0) { 1437 return false; 1438 } 1439 return os::stat(filename, &statbuf) == 0; 1440 } 1441 1442 bool os::dll_build_name(char* buffer, size_t buflen, 1443 const char* pname, const char* fname) { 1444 bool retval = false; 1445 // Copied from libhpi 1446 const size_t pnamelen = pname ? strlen(pname) : 0; 1447 1448 // Return error on buffer overflow. 1449 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1450 return retval; 1451 } 1452 1453 if (pnamelen == 0) { 1454 snprintf(buffer, buflen, "lib%s.so", fname); 1455 retval = true; 1456 } else if (strchr(pname, *os::path_separator()) != NULL) { 1457 int n; 1458 char** pelements = split_path(pname, &n); 1459 if (pelements == NULL) { 1460 return false; 1461 } 1462 for (int i = 0; i < n; i++) { 1463 // Really shouldn't be NULL, but check can't hurt 1464 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1465 continue; // skip the empty path values 1466 } 1467 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1468 if (file_exists(buffer)) { 1469 retval = true; 1470 break; 1471 } 1472 } 1473 // release the storage 1474 for (int i = 0; i < n; i++) { 1475 if (pelements[i] != NULL) { 1476 FREE_C_HEAP_ARRAY(char, pelements[i]); 1477 } 1478 } 1479 if (pelements != NULL) { 1480 FREE_C_HEAP_ARRAY(char*, pelements); 1481 } 1482 } else { 1483 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1484 retval = true; 1485 } 1486 return retval; 1487 } 1488 1489 // check if addr is inside libjvm.so 1490 bool os::address_is_in_vm(address addr) { 1491 static address libjvm_base_addr; 1492 Dl_info dlinfo; 1493 1494 if (libjvm_base_addr == NULL) { 1495 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1496 libjvm_base_addr = (address)dlinfo.dli_fbase; 1497 } 1498 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1499 } 1500 1501 if (dladdr((void *)addr, &dlinfo) != 0) { 1502 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1503 } 1504 1505 return false; 1506 } 1507 1508 bool os::dll_address_to_function_name(address addr, char *buf, 1509 int buflen, int *offset, 1510 bool demangle) { 1511 // buf is not optional, but offset is optional 1512 assert(buf != NULL, "sanity check"); 1513 1514 Dl_info dlinfo; 1515 1516 if (dladdr((void*)addr, &dlinfo) != 0) { 1517 // see if we have a matching symbol 1518 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1519 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1520 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1521 } 1522 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1523 return true; 1524 } 1525 // no matching symbol so try for just file info 1526 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1527 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1528 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1529 return true; 1530 } 1531 } 1532 } 1533 1534 buf[0] = '\0'; 1535 if (offset != NULL) *offset = -1; 1536 return false; 1537 } 1538 1539 struct _address_to_library_name { 1540 address addr; // input : memory address 1541 size_t buflen; // size of fname 1542 char* fname; // output: library name 1543 address base; // library base addr 1544 }; 1545 1546 static int address_to_library_name_callback(struct dl_phdr_info *info, 1547 size_t size, void *data) { 1548 int i; 1549 bool found = false; 1550 address libbase = NULL; 1551 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1552 1553 // iterate through all loadable segments 1554 for (i = 0; i < info->dlpi_phnum; i++) { 1555 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1556 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1557 // base address of a library is the lowest address of its loaded 1558 // segments. 1559 if (libbase == NULL || libbase > segbase) { 1560 libbase = segbase; 1561 } 1562 // see if 'addr' is within current segment 1563 if (segbase <= d->addr && 1564 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1565 found = true; 1566 } 1567 } 1568 } 1569 1570 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1571 // so dll_address_to_library_name() can fall through to use dladdr() which 1572 // can figure out executable name from argv[0]. 1573 if (found && info->dlpi_name && info->dlpi_name[0]) { 1574 d->base = libbase; 1575 if (d->fname) { 1576 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1577 } 1578 return 1; 1579 } 1580 return 0; 1581 } 1582 1583 bool os::dll_address_to_library_name(address addr, char* buf, 1584 int buflen, int* offset) { 1585 // buf is not optional, but offset is optional 1586 assert(buf != NULL, "sanity check"); 1587 1588 Dl_info dlinfo; 1589 struct _address_to_library_name data; 1590 1591 // There is a bug in old glibc dladdr() implementation that it could resolve 1592 // to wrong library name if the .so file has a base address != NULL. Here 1593 // we iterate through the program headers of all loaded libraries to find 1594 // out which library 'addr' really belongs to. This workaround can be 1595 // removed once the minimum requirement for glibc is moved to 2.3.x. 1596 data.addr = addr; 1597 data.fname = buf; 1598 data.buflen = buflen; 1599 data.base = NULL; 1600 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1601 1602 if (rslt) { 1603 // buf already contains library name 1604 if (offset) *offset = addr - data.base; 1605 return true; 1606 } 1607 if (dladdr((void*)addr, &dlinfo) != 0) { 1608 if (dlinfo.dli_fname != NULL) { 1609 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1610 } 1611 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1612 *offset = addr - (address)dlinfo.dli_fbase; 1613 } 1614 return true; 1615 } 1616 1617 buf[0] = '\0'; 1618 if (offset) *offset = -1; 1619 return false; 1620 } 1621 1622 // Loads .dll/.so and 1623 // in case of error it checks if .dll/.so was built for the 1624 // same architecture as Hotspot is running on 1625 1626 1627 // Remember the stack's state. The Linux dynamic linker will change 1628 // the stack to 'executable' at most once, so we must safepoint only once. 1629 bool os::Linux::_stack_is_executable = false; 1630 1631 // VM operation that loads a library. This is necessary if stack protection 1632 // of the Java stacks can be lost during loading the library. If we 1633 // do not stop the Java threads, they can stack overflow before the stacks 1634 // are protected again. 1635 class VM_LinuxDllLoad: public VM_Operation { 1636 private: 1637 const char *_filename; 1638 char *_ebuf; 1639 int _ebuflen; 1640 void *_lib; 1641 public: 1642 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1643 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1644 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1645 void doit() { 1646 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1647 os::Linux::_stack_is_executable = true; 1648 } 1649 void* loaded_library() { return _lib; } 1650 }; 1651 1652 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1653 void * result = NULL; 1654 bool load_attempted = false; 1655 1656 // Check whether the library to load might change execution rights 1657 // of the stack. If they are changed, the protection of the stack 1658 // guard pages will be lost. We need a safepoint to fix this. 1659 // 1660 // See Linux man page execstack(8) for more info. 1661 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1662 ElfFile ef(filename); 1663 if (!ef.specifies_noexecstack()) { 1664 if (!is_init_completed()) { 1665 os::Linux::_stack_is_executable = true; 1666 // This is OK - No Java threads have been created yet, and hence no 1667 // stack guard pages to fix. 1668 // 1669 // This should happen only when you are building JDK7 using a very 1670 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1671 // 1672 // Dynamic loader will make all stacks executable after 1673 // this function returns, and will not do that again. 1674 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1675 } else { 1676 warning("You have loaded library %s which might have disabled stack guard. " 1677 "The VM will try to fix the stack guard now.\n" 1678 "It's highly recommended that you fix the library with " 1679 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1680 filename); 1681 1682 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1683 JavaThread *jt = JavaThread::current(); 1684 if (jt->thread_state() != _thread_in_native) { 1685 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1686 // that requires ExecStack. Cannot enter safe point. Let's give up. 1687 warning("Unable to fix stack guard. Giving up."); 1688 } else { 1689 if (!LoadExecStackDllInVMThread) { 1690 // This is for the case where the DLL has an static 1691 // constructor function that executes JNI code. We cannot 1692 // load such DLLs in the VMThread. 1693 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1694 } 1695 1696 ThreadInVMfromNative tiv(jt); 1697 debug_only(VMNativeEntryWrapper vew;) 1698 1699 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1700 VMThread::execute(&op); 1701 if (LoadExecStackDllInVMThread) { 1702 result = op.loaded_library(); 1703 } 1704 load_attempted = true; 1705 } 1706 } 1707 } 1708 } 1709 1710 if (!load_attempted) { 1711 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1712 } 1713 1714 if (result != NULL) { 1715 // Successful loading 1716 return result; 1717 } 1718 1719 Elf32_Ehdr elf_head; 1720 int diag_msg_max_length=ebuflen-strlen(ebuf); 1721 char* diag_msg_buf=ebuf+strlen(ebuf); 1722 1723 if (diag_msg_max_length==0) { 1724 // No more space in ebuf for additional diagnostics message 1725 return NULL; 1726 } 1727 1728 1729 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1730 1731 if (file_descriptor < 0) { 1732 // Can't open library, report dlerror() message 1733 return NULL; 1734 } 1735 1736 bool failed_to_read_elf_head= 1737 (sizeof(elf_head)!= 1738 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1739 1740 ::close(file_descriptor); 1741 if (failed_to_read_elf_head) { 1742 // file i/o error - report dlerror() msg 1743 return NULL; 1744 } 1745 1746 typedef struct { 1747 Elf32_Half code; // Actual value as defined in elf.h 1748 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1749 char elf_class; // 32 or 64 bit 1750 char endianess; // MSB or LSB 1751 char* name; // String representation 1752 } arch_t; 1753 1754 #ifndef EM_486 1755 #define EM_486 6 /* Intel 80486 */ 1756 #endif 1757 #ifndef EM_AARCH64 1758 #define EM_AARCH64 183 /* ARM AARCH64 */ 1759 #endif 1760 1761 static const arch_t arch_array[]={ 1762 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1763 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1764 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1765 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1766 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1767 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1768 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1769 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1770 #if defined(VM_LITTLE_ENDIAN) 1771 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1772 #else 1773 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1774 #endif 1775 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1776 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1777 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1778 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1779 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1780 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1781 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1782 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1783 }; 1784 1785 #if (defined IA32) 1786 static Elf32_Half running_arch_code=EM_386; 1787 #elif (defined AMD64) 1788 static Elf32_Half running_arch_code=EM_X86_64; 1789 #elif (defined IA64) 1790 static Elf32_Half running_arch_code=EM_IA_64; 1791 #elif (defined __sparc) && (defined _LP64) 1792 static Elf32_Half running_arch_code=EM_SPARCV9; 1793 #elif (defined __sparc) && (!defined _LP64) 1794 static Elf32_Half running_arch_code=EM_SPARC; 1795 #elif (defined __powerpc64__) 1796 static Elf32_Half running_arch_code=EM_PPC64; 1797 #elif (defined __powerpc__) 1798 static Elf32_Half running_arch_code=EM_PPC; 1799 #elif (defined ARM) 1800 static Elf32_Half running_arch_code=EM_ARM; 1801 #elif (defined S390) 1802 static Elf32_Half running_arch_code=EM_S390; 1803 #elif (defined ALPHA) 1804 static Elf32_Half running_arch_code=EM_ALPHA; 1805 #elif (defined MIPSEL) 1806 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1807 #elif (defined PARISC) 1808 static Elf32_Half running_arch_code=EM_PARISC; 1809 #elif (defined MIPS) 1810 static Elf32_Half running_arch_code=EM_MIPS; 1811 #elif (defined M68K) 1812 static Elf32_Half running_arch_code=EM_68K; 1813 #elif (defined AARCH64) 1814 static Elf32_Half running_arch_code=EM_AARCH64; 1815 #else 1816 #error Method os::dll_load requires that one of following is defined:\ 1817 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64 1818 #endif 1819 1820 // Identify compatability class for VM's architecture and library's architecture 1821 // Obtain string descriptions for architectures 1822 1823 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1824 int running_arch_index=-1; 1825 1826 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1827 if (running_arch_code == arch_array[i].code) { 1828 running_arch_index = i; 1829 } 1830 if (lib_arch.code == arch_array[i].code) { 1831 lib_arch.compat_class = arch_array[i].compat_class; 1832 lib_arch.name = arch_array[i].name; 1833 } 1834 } 1835 1836 assert(running_arch_index != -1, 1837 "Didn't find running architecture code (running_arch_code) in arch_array"); 1838 if (running_arch_index == -1) { 1839 // Even though running architecture detection failed 1840 // we may still continue with reporting dlerror() message 1841 return NULL; 1842 } 1843 1844 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1845 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1846 return NULL; 1847 } 1848 1849 #ifndef S390 1850 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1851 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1852 return NULL; 1853 } 1854 #endif // !S390 1855 1856 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1857 if (lib_arch.name!=NULL) { 1858 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1859 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1860 lib_arch.name, arch_array[running_arch_index].name); 1861 } else { 1862 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1863 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1864 lib_arch.code, 1865 arch_array[running_arch_index].name); 1866 } 1867 } 1868 1869 return NULL; 1870 } 1871 1872 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1873 int ebuflen) { 1874 void * result = ::dlopen(filename, RTLD_LAZY); 1875 if (result == NULL) { 1876 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1877 ebuf[ebuflen-1] = '\0'; 1878 } 1879 return result; 1880 } 1881 1882 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1883 int ebuflen) { 1884 void * result = NULL; 1885 if (LoadExecStackDllInVMThread) { 1886 result = dlopen_helper(filename, ebuf, ebuflen); 1887 } 1888 1889 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1890 // library that requires an executable stack, or which does not have this 1891 // stack attribute set, dlopen changes the stack attribute to executable. The 1892 // read protection of the guard pages gets lost. 1893 // 1894 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1895 // may have been queued at the same time. 1896 1897 if (!_stack_is_executable) { 1898 JavaThread *jt = Threads::first(); 1899 1900 while (jt) { 1901 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1902 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 1903 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 1904 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 1905 warning("Attempt to reguard stack yellow zone failed."); 1906 } 1907 } 1908 jt = jt->next(); 1909 } 1910 } 1911 1912 return result; 1913 } 1914 1915 void* os::dll_lookup(void* handle, const char* name) { 1916 void* res = dlsym(handle, name); 1917 return res; 1918 } 1919 1920 void* os::get_default_process_handle() { 1921 return (void*)::dlopen(NULL, RTLD_LAZY); 1922 } 1923 1924 static bool _print_ascii_file(const char* filename, outputStream* st) { 1925 int fd = ::open(filename, O_RDONLY); 1926 if (fd == -1) { 1927 return false; 1928 } 1929 1930 char buf[32]; 1931 int bytes; 1932 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1933 st->print_raw(buf, bytes); 1934 } 1935 1936 ::close(fd); 1937 1938 return true; 1939 } 1940 1941 void os::print_dll_info(outputStream *st) { 1942 st->print_cr("Dynamic libraries:"); 1943 1944 char fname[32]; 1945 pid_t pid = os::Linux::gettid(); 1946 1947 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1948 1949 if (!_print_ascii_file(fname, st)) { 1950 st->print("Can not get library information for pid = %d\n", pid); 1951 } 1952 } 1953 1954 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1955 FILE *procmapsFile = NULL; 1956 1957 // Open the procfs maps file for the current process 1958 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1959 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1960 char line[PATH_MAX + 100]; 1961 1962 // Read line by line from 'file' 1963 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1964 u8 base, top, offset, inode; 1965 char permissions[5]; 1966 char device[6]; 1967 char name[PATH_MAX + 1]; 1968 1969 // Parse fields from line 1970 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1971 &base, &top, permissions, &offset, device, &inode, name); 1972 1973 // Filter by device id '00:00' so that we only get file system mapped files. 1974 if (strcmp(device, "00:00") != 0) { 1975 1976 // Call callback with the fields of interest 1977 if(callback(name, (address)base, (address)top, param)) { 1978 // Oops abort, callback aborted 1979 fclose(procmapsFile); 1980 return 1; 1981 } 1982 } 1983 } 1984 fclose(procmapsFile); 1985 } 1986 return 0; 1987 } 1988 1989 void os::print_os_info_brief(outputStream* st) { 1990 os::Linux::print_distro_info(st); 1991 1992 os::Posix::print_uname_info(st); 1993 1994 os::Linux::print_libversion_info(st); 1995 1996 } 1997 1998 void os::print_os_info(outputStream* st) { 1999 st->print("OS:"); 2000 2001 os::Linux::print_distro_info(st); 2002 2003 os::Posix::print_uname_info(st); 2004 2005 // Print warning if unsafe chroot environment detected 2006 if (unsafe_chroot_detected) { 2007 st->print("WARNING!! "); 2008 st->print_cr("%s", unstable_chroot_error); 2009 } 2010 2011 os::Linux::print_libversion_info(st); 2012 2013 os::Posix::print_rlimit_info(st); 2014 2015 os::Posix::print_load_average(st); 2016 2017 os::Linux::print_full_memory_info(st); 2018 } 2019 2020 // Try to identify popular distros. 2021 // Most Linux distributions have a /etc/XXX-release file, which contains 2022 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2023 // file that also contains the OS version string. Some have more than one 2024 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2025 // /etc/redhat-release.), so the order is important. 2026 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2027 // their own specific XXX-release file as well as a redhat-release file. 2028 // Because of this the XXX-release file needs to be searched for before the 2029 // redhat-release file. 2030 // Since Red Hat has a lsb-release file that is not very descriptive the 2031 // search for redhat-release needs to be before lsb-release. 2032 // Since the lsb-release file is the new standard it needs to be searched 2033 // before the older style release files. 2034 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2035 // next to last resort. The os-release file is a new standard that contains 2036 // distribution information and the system-release file seems to be an old 2037 // standard that has been replaced by the lsb-release and os-release files. 2038 // Searching for the debian_version file is the last resort. It contains 2039 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2040 // "Debian " is printed before the contents of the debian_version file. 2041 2042 const char* distro_files[] = { 2043 "/etc/oracle-release", 2044 "/etc/mandriva-release", 2045 "/etc/mandrake-release", 2046 "/etc/sun-release", 2047 "/etc/redhat-release", 2048 "/etc/lsb-release", 2049 "/etc/SuSE-release", 2050 "/etc/turbolinux-release", 2051 "/etc/gentoo-release", 2052 "/etc/ltib-release", 2053 "/etc/angstrom-version", 2054 "/etc/system-release", 2055 "/etc/os-release", 2056 NULL }; 2057 2058 void os::Linux::print_distro_info(outputStream* st) { 2059 for (int i = 0;; i++) { 2060 const char* file = distro_files[i]; 2061 if (file == NULL) { 2062 break; // done 2063 } 2064 // If file prints, we found it. 2065 if (_print_ascii_file(file, st)) { 2066 return; 2067 } 2068 } 2069 2070 if (file_exists("/etc/debian_version")) { 2071 st->print("Debian "); 2072 _print_ascii_file("/etc/debian_version", st); 2073 } else { 2074 st->print("Linux"); 2075 } 2076 st->cr(); 2077 } 2078 2079 static void parse_os_info(char* distro, size_t length, const char* file) { 2080 FILE* fp = fopen(file, "r"); 2081 if (fp != NULL) { 2082 char buf[256]; 2083 // get last line of the file. 2084 while (fgets(buf, sizeof(buf), fp)) { } 2085 // Edit out extra stuff in expected ubuntu format 2086 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL) { 2087 char* ptr = strstr(buf, "\""); // the name is in quotes 2088 if (ptr != NULL) { 2089 ptr++; // go beyond first quote 2090 char* nl = strchr(ptr, '\"'); 2091 if (nl != NULL) *nl = '\0'; 2092 strncpy(distro, ptr, length); 2093 } else { 2094 ptr = strstr(buf, "="); 2095 ptr++; // go beyond equals then 2096 char* nl = strchr(ptr, '\n'); 2097 if (nl != NULL) *nl = '\0'; 2098 strncpy(distro, ptr, length); 2099 } 2100 } else { 2101 // if not in expected Ubuntu format, print out whole line minus \n 2102 char* nl = strchr(buf, '\n'); 2103 if (nl != NULL) *nl = '\0'; 2104 strncpy(distro, buf, length); 2105 } 2106 // close distro file 2107 fclose(fp); 2108 } 2109 } 2110 2111 void os::get_summary_os_info(char* buf, size_t buflen) { 2112 for (int i = 0;; i++) { 2113 const char* file = distro_files[i]; 2114 if (file == NULL) { 2115 break; // ran out of distro_files 2116 } 2117 if (file_exists(file)) { 2118 parse_os_info(buf, buflen, file); 2119 return; 2120 } 2121 } 2122 // special case for debian 2123 if (file_exists("/etc/debian_version")) { 2124 strncpy(buf, "Debian ", buflen); 2125 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2126 } else { 2127 strncpy(buf, "Linux", buflen); 2128 } 2129 } 2130 2131 void os::Linux::print_libversion_info(outputStream* st) { 2132 // libc, pthread 2133 st->print("libc:"); 2134 st->print("%s ", os::Linux::glibc_version()); 2135 st->print("%s ", os::Linux::libpthread_version()); 2136 st->cr(); 2137 } 2138 2139 void os::Linux::print_full_memory_info(outputStream* st) { 2140 st->print("\n/proc/meminfo:\n"); 2141 _print_ascii_file("/proc/meminfo", st); 2142 st->cr(); 2143 } 2144 2145 void os::print_memory_info(outputStream* st) { 2146 2147 st->print("Memory:"); 2148 st->print(" %dk page", os::vm_page_size()>>10); 2149 2150 // values in struct sysinfo are "unsigned long" 2151 struct sysinfo si; 2152 sysinfo(&si); 2153 2154 st->print(", physical " UINT64_FORMAT "k", 2155 os::physical_memory() >> 10); 2156 st->print("(" UINT64_FORMAT "k free)", 2157 os::available_memory() >> 10); 2158 st->print(", swap " UINT64_FORMAT "k", 2159 ((jlong)si.totalswap * si.mem_unit) >> 10); 2160 st->print("(" UINT64_FORMAT "k free)", 2161 ((jlong)si.freeswap * si.mem_unit) >> 10); 2162 st->cr(); 2163 } 2164 2165 // Print the first "model name" line and the first "flags" line 2166 // that we find and nothing more. We assume "model name" comes 2167 // before "flags" so if we find a second "model name", then the 2168 // "flags" field is considered missing. 2169 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2170 #if defined(IA32) || defined(AMD64) 2171 // Other platforms have less repetitive cpuinfo files 2172 FILE *fp = fopen("/proc/cpuinfo", "r"); 2173 if (fp) { 2174 while (!feof(fp)) { 2175 if (fgets(buf, buflen, fp)) { 2176 // Assume model name comes before flags 2177 bool model_name_printed = false; 2178 if (strstr(buf, "model name") != NULL) { 2179 if (!model_name_printed) { 2180 st->print_raw("\nCPU Model and flags from /proc/cpuinfo:\n"); 2181 st->print_raw(buf); 2182 model_name_printed = true; 2183 } else { 2184 // model name printed but not flags? Odd, just return 2185 fclose(fp); 2186 return true; 2187 } 2188 } 2189 // print the flags line too 2190 if (strstr(buf, "flags") != NULL) { 2191 st->print_raw(buf); 2192 fclose(fp); 2193 return true; 2194 } 2195 } 2196 } 2197 fclose(fp); 2198 } 2199 #endif // x86 platforms 2200 return false; 2201 } 2202 2203 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2204 // Only print the model name if the platform provides this as a summary 2205 if (!print_model_name_and_flags(st, buf, buflen)) { 2206 st->print("\n/proc/cpuinfo:\n"); 2207 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2208 st->print_cr(" <Not Available>"); 2209 } 2210 } 2211 } 2212 2213 #if defined(AMD64) || defined(IA32) || defined(X32) 2214 const char* search_string = "model name"; 2215 #elif defined(SPARC) 2216 const char* search_string = "cpu"; 2217 #else 2218 const char* search_string = "Processor"; 2219 #endif 2220 2221 // Parses the cpuinfo file for string representing the model name. 2222 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2223 FILE* fp = fopen("/proc/cpuinfo", "r"); 2224 if (fp != NULL) { 2225 while (!feof(fp)) { 2226 char buf[256]; 2227 if (fgets(buf, sizeof(buf), fp)) { 2228 char* start = strstr(buf, search_string); 2229 if (start != NULL) { 2230 char *ptr = start + strlen(search_string); 2231 char *end = buf + strlen(buf); 2232 while (ptr != end) { 2233 // skip whitespace and colon for the rest of the name. 2234 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2235 break; 2236 } 2237 ptr++; 2238 } 2239 if (ptr != end) { 2240 // reasonable string, get rid of newline and keep the rest 2241 char* nl = strchr(buf, '\n'); 2242 if (nl != NULL) *nl = '\0'; 2243 strncpy(cpuinfo, ptr, length); 2244 fclose(fp); 2245 return; 2246 } 2247 } 2248 } 2249 } 2250 fclose(fp); 2251 } 2252 // cpuinfo not found or parsing failed, just print generic string. The entire 2253 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2254 #if defined(AMD64) 2255 strncpy(cpuinfo, "x86_64", length); 2256 #elif defined(IA32) 2257 strncpy(cpuinfo, "x86_32", length); 2258 #elif defined(IA64) 2259 strncpy(cpuinfo, "IA64", length); 2260 #elif defined(SPARC) 2261 strncpy(cpuinfo, "sparcv9", length); 2262 #elif defined(AARCH64) 2263 strncpy(cpuinfo, "AArch64", length); 2264 #elif defined(ARM) 2265 strncpy(cpuinfo, "ARM", length); 2266 #elif defined(PPC) 2267 strncpy(cpuinfo, "PPC64", length); 2268 #elif defined(ZERO_LIBARCH) 2269 strncpy(cpuinfo, ZERO_LIBARCH, length); 2270 #else 2271 strncpy(cpuinfo, "unknown", length); 2272 #endif 2273 } 2274 2275 void os::print_siginfo(outputStream* st, void* siginfo) { 2276 const siginfo_t* si = (const siginfo_t*)siginfo; 2277 2278 os::Posix::print_siginfo_brief(st, si); 2279 #if INCLUDE_CDS 2280 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2281 UseSharedSpaces) { 2282 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2283 if (mapinfo->is_in_shared_space(si->si_addr)) { 2284 st->print("\n\nError accessing class data sharing archive." \ 2285 " Mapped file inaccessible during execution, " \ 2286 " possible disk/network problem."); 2287 } 2288 } 2289 #endif 2290 st->cr(); 2291 } 2292 2293 2294 static void print_signal_handler(outputStream* st, int sig, 2295 char* buf, size_t buflen); 2296 2297 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2298 st->print_cr("Signal Handlers:"); 2299 print_signal_handler(st, SIGSEGV, buf, buflen); 2300 print_signal_handler(st, SIGBUS , buf, buflen); 2301 print_signal_handler(st, SIGFPE , buf, buflen); 2302 print_signal_handler(st, SIGPIPE, buf, buflen); 2303 print_signal_handler(st, SIGXFSZ, buf, buflen); 2304 print_signal_handler(st, SIGILL , buf, buflen); 2305 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2306 print_signal_handler(st, SR_signum, buf, buflen); 2307 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2308 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2309 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2310 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2311 #if defined(PPC64) 2312 print_signal_handler(st, SIGTRAP, buf, buflen); 2313 #endif 2314 } 2315 2316 static char saved_jvm_path[MAXPATHLEN] = {0}; 2317 2318 // Find the full path to the current module, libjvm.so 2319 void os::jvm_path(char *buf, jint buflen) { 2320 // Error checking. 2321 if (buflen < MAXPATHLEN) { 2322 assert(false, "must use a large-enough buffer"); 2323 buf[0] = '\0'; 2324 return; 2325 } 2326 // Lazy resolve the path to current module. 2327 if (saved_jvm_path[0] != 0) { 2328 strcpy(buf, saved_jvm_path); 2329 return; 2330 } 2331 2332 char dli_fname[MAXPATHLEN]; 2333 bool ret = dll_address_to_library_name( 2334 CAST_FROM_FN_PTR(address, os::jvm_path), 2335 dli_fname, sizeof(dli_fname), NULL); 2336 assert(ret, "cannot locate libjvm"); 2337 char *rp = NULL; 2338 if (ret && dli_fname[0] != '\0') { 2339 rp = realpath(dli_fname, buf); 2340 } 2341 if (rp == NULL) { 2342 return; 2343 } 2344 2345 if (Arguments::sun_java_launcher_is_altjvm()) { 2346 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2347 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2348 // If "/jre/lib/" appears at the right place in the string, then 2349 // assume we are installed in a JDK and we're done. Otherwise, check 2350 // for a JAVA_HOME environment variable and fix up the path so it 2351 // looks like libjvm.so is installed there (append a fake suffix 2352 // hotspot/libjvm.so). 2353 const char *p = buf + strlen(buf) - 1; 2354 for (int count = 0; p > buf && count < 5; ++count) { 2355 for (--p; p > buf && *p != '/'; --p) 2356 /* empty */ ; 2357 } 2358 2359 if (strncmp(p, "/jre/lib/", 9) != 0) { 2360 // Look for JAVA_HOME in the environment. 2361 char* java_home_var = ::getenv("JAVA_HOME"); 2362 if (java_home_var != NULL && java_home_var[0] != 0) { 2363 char* jrelib_p; 2364 int len; 2365 2366 // Check the current module name "libjvm.so". 2367 p = strrchr(buf, '/'); 2368 if (p == NULL) { 2369 return; 2370 } 2371 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2372 2373 rp = realpath(java_home_var, buf); 2374 if (rp == NULL) { 2375 return; 2376 } 2377 2378 // determine if this is a legacy image or modules image 2379 // modules image doesn't have "jre" subdirectory 2380 len = strlen(buf); 2381 assert(len < buflen, "Ran out of buffer room"); 2382 jrelib_p = buf + len; 2383 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2384 if (0 != access(buf, F_OK)) { 2385 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2386 } 2387 2388 if (0 == access(buf, F_OK)) { 2389 // Use current module name "libjvm.so" 2390 len = strlen(buf); 2391 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2392 } else { 2393 // Go back to path of .so 2394 rp = realpath(dli_fname, buf); 2395 if (rp == NULL) { 2396 return; 2397 } 2398 } 2399 } 2400 } 2401 } 2402 2403 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2404 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2405 } 2406 2407 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2408 // no prefix required, not even "_" 2409 } 2410 2411 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2412 // no suffix required 2413 } 2414 2415 //////////////////////////////////////////////////////////////////////////////// 2416 // sun.misc.Signal support 2417 2418 static volatile jint sigint_count = 0; 2419 2420 static void UserHandler(int sig, void *siginfo, void *context) { 2421 // 4511530 - sem_post is serialized and handled by the manager thread. When 2422 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2423 // don't want to flood the manager thread with sem_post requests. 2424 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2425 return; 2426 } 2427 2428 // Ctrl-C is pressed during error reporting, likely because the error 2429 // handler fails to abort. Let VM die immediately. 2430 if (sig == SIGINT && is_error_reported()) { 2431 os::die(); 2432 } 2433 2434 os::signal_notify(sig); 2435 } 2436 2437 void* os::user_handler() { 2438 return CAST_FROM_FN_PTR(void*, UserHandler); 2439 } 2440 2441 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2442 struct timespec ts; 2443 // Semaphore's are always associated with CLOCK_REALTIME 2444 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2445 // see unpackTime for discussion on overflow checking 2446 if (sec >= MAX_SECS) { 2447 ts.tv_sec += MAX_SECS; 2448 ts.tv_nsec = 0; 2449 } else { 2450 ts.tv_sec += sec; 2451 ts.tv_nsec += nsec; 2452 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2453 ts.tv_nsec -= NANOSECS_PER_SEC; 2454 ++ts.tv_sec; // note: this must be <= max_secs 2455 } 2456 } 2457 2458 return ts; 2459 } 2460 2461 extern "C" { 2462 typedef void (*sa_handler_t)(int); 2463 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2464 } 2465 2466 void* os::signal(int signal_number, void* handler) { 2467 struct sigaction sigAct, oldSigAct; 2468 2469 sigfillset(&(sigAct.sa_mask)); 2470 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2471 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2472 2473 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2474 // -1 means registration failed 2475 return (void *)-1; 2476 } 2477 2478 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2479 } 2480 2481 void os::signal_raise(int signal_number) { 2482 ::raise(signal_number); 2483 } 2484 2485 // The following code is moved from os.cpp for making this 2486 // code platform specific, which it is by its very nature. 2487 2488 // Will be modified when max signal is changed to be dynamic 2489 int os::sigexitnum_pd() { 2490 return NSIG; 2491 } 2492 2493 // a counter for each possible signal value 2494 static volatile jint pending_signals[NSIG+1] = { 0 }; 2495 2496 // Linux(POSIX) specific hand shaking semaphore. 2497 static sem_t sig_sem; 2498 static PosixSemaphore sr_semaphore; 2499 2500 void os::signal_init_pd() { 2501 // Initialize signal structures 2502 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2503 2504 // Initialize signal semaphore 2505 ::sem_init(&sig_sem, 0, 0); 2506 } 2507 2508 void os::signal_notify(int sig) { 2509 Atomic::inc(&pending_signals[sig]); 2510 ::sem_post(&sig_sem); 2511 } 2512 2513 static int check_pending_signals(bool wait) { 2514 Atomic::store(0, &sigint_count); 2515 for (;;) { 2516 for (int i = 0; i < NSIG + 1; i++) { 2517 jint n = pending_signals[i]; 2518 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2519 return i; 2520 } 2521 } 2522 if (!wait) { 2523 return -1; 2524 } 2525 JavaThread *thread = JavaThread::current(); 2526 ThreadBlockInVM tbivm(thread); 2527 2528 bool threadIsSuspended; 2529 do { 2530 thread->set_suspend_equivalent(); 2531 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2532 ::sem_wait(&sig_sem); 2533 2534 // were we externally suspended while we were waiting? 2535 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2536 if (threadIsSuspended) { 2537 // The semaphore has been incremented, but while we were waiting 2538 // another thread suspended us. We don't want to continue running 2539 // while suspended because that would surprise the thread that 2540 // suspended us. 2541 ::sem_post(&sig_sem); 2542 2543 thread->java_suspend_self(); 2544 } 2545 } while (threadIsSuspended); 2546 } 2547 } 2548 2549 int os::signal_lookup() { 2550 return check_pending_signals(false); 2551 } 2552 2553 int os::signal_wait() { 2554 return check_pending_signals(true); 2555 } 2556 2557 //////////////////////////////////////////////////////////////////////////////// 2558 // Virtual Memory 2559 2560 int os::vm_page_size() { 2561 // Seems redundant as all get out 2562 assert(os::Linux::page_size() != -1, "must call os::init"); 2563 return os::Linux::page_size(); 2564 } 2565 2566 // Solaris allocates memory by pages. 2567 int os::vm_allocation_granularity() { 2568 assert(os::Linux::page_size() != -1, "must call os::init"); 2569 return os::Linux::page_size(); 2570 } 2571 2572 // Rationale behind this function: 2573 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2574 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2575 // samples for JITted code. Here we create private executable mapping over the code cache 2576 // and then we can use standard (well, almost, as mapping can change) way to provide 2577 // info for the reporting script by storing timestamp and location of symbol 2578 void linux_wrap_code(char* base, size_t size) { 2579 static volatile jint cnt = 0; 2580 2581 if (!UseOprofile) { 2582 return; 2583 } 2584 2585 char buf[PATH_MAX+1]; 2586 int num = Atomic::add(1, &cnt); 2587 2588 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2589 os::get_temp_directory(), os::current_process_id(), num); 2590 unlink(buf); 2591 2592 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2593 2594 if (fd != -1) { 2595 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2596 if (rv != (off_t)-1) { 2597 if (::write(fd, "", 1) == 1) { 2598 mmap(base, size, 2599 PROT_READ|PROT_WRITE|PROT_EXEC, 2600 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2601 } 2602 } 2603 ::close(fd); 2604 unlink(buf); 2605 } 2606 } 2607 2608 static bool recoverable_mmap_error(int err) { 2609 // See if the error is one we can let the caller handle. This 2610 // list of errno values comes from JBS-6843484. I can't find a 2611 // Linux man page that documents this specific set of errno 2612 // values so while this list currently matches Solaris, it may 2613 // change as we gain experience with this failure mode. 2614 switch (err) { 2615 case EBADF: 2616 case EINVAL: 2617 case ENOTSUP: 2618 // let the caller deal with these errors 2619 return true; 2620 2621 default: 2622 // Any remaining errors on this OS can cause our reserved mapping 2623 // to be lost. That can cause confusion where different data 2624 // structures think they have the same memory mapped. The worst 2625 // scenario is if both the VM and a library think they have the 2626 // same memory mapped. 2627 return false; 2628 } 2629 } 2630 2631 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2632 int err) { 2633 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2634 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2635 strerror(err), err); 2636 } 2637 2638 static void warn_fail_commit_memory(char* addr, size_t size, 2639 size_t alignment_hint, bool exec, 2640 int err) { 2641 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2642 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2643 alignment_hint, exec, strerror(err), err); 2644 } 2645 2646 // NOTE: Linux kernel does not really reserve the pages for us. 2647 // All it does is to check if there are enough free pages 2648 // left at the time of mmap(). This could be a potential 2649 // problem. 2650 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2651 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2652 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2653 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2654 if (res != (uintptr_t) MAP_FAILED) { 2655 if (UseNUMAInterleaving) { 2656 numa_make_global(addr, size); 2657 } 2658 return 0; 2659 } 2660 2661 int err = errno; // save errno from mmap() call above 2662 2663 if (!recoverable_mmap_error(err)) { 2664 warn_fail_commit_memory(addr, size, exec, err); 2665 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2666 } 2667 2668 return err; 2669 } 2670 2671 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2672 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2673 } 2674 2675 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2676 const char* mesg) { 2677 assert(mesg != NULL, "mesg must be specified"); 2678 int err = os::Linux::commit_memory_impl(addr, size, exec); 2679 if (err != 0) { 2680 // the caller wants all commit errors to exit with the specified mesg: 2681 warn_fail_commit_memory(addr, size, exec, err); 2682 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2683 } 2684 } 2685 2686 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2687 #ifndef MAP_HUGETLB 2688 #define MAP_HUGETLB 0x40000 2689 #endif 2690 2691 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2692 #ifndef MADV_HUGEPAGE 2693 #define MADV_HUGEPAGE 14 2694 #endif 2695 2696 int os::Linux::commit_memory_impl(char* addr, size_t size, 2697 size_t alignment_hint, bool exec) { 2698 int err = os::Linux::commit_memory_impl(addr, size, exec); 2699 if (err == 0) { 2700 realign_memory(addr, size, alignment_hint); 2701 } 2702 return err; 2703 } 2704 2705 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2706 bool exec) { 2707 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2708 } 2709 2710 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2711 size_t alignment_hint, bool exec, 2712 const char* mesg) { 2713 assert(mesg != NULL, "mesg must be specified"); 2714 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2715 if (err != 0) { 2716 // the caller wants all commit errors to exit with the specified mesg: 2717 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2718 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2719 } 2720 } 2721 2722 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2723 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2724 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2725 // be supported or the memory may already be backed by huge pages. 2726 ::madvise(addr, bytes, MADV_HUGEPAGE); 2727 } 2728 } 2729 2730 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2731 // This method works by doing an mmap over an existing mmaping and effectively discarding 2732 // the existing pages. However it won't work for SHM-based large pages that cannot be 2733 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2734 // small pages on top of the SHM segment. This method always works for small pages, so we 2735 // allow that in any case. 2736 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2737 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2738 } 2739 } 2740 2741 void os::numa_make_global(char *addr, size_t bytes) { 2742 Linux::numa_interleave_memory(addr, bytes); 2743 } 2744 2745 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2746 // bind policy to MPOL_PREFERRED for the current thread. 2747 #define USE_MPOL_PREFERRED 0 2748 2749 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2750 // To make NUMA and large pages more robust when both enabled, we need to ease 2751 // the requirements on where the memory should be allocated. MPOL_BIND is the 2752 // default policy and it will force memory to be allocated on the specified 2753 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2754 // the specified node, but will not force it. Using this policy will prevent 2755 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2756 // free large pages. 2757 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2758 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2759 } 2760 2761 bool os::numa_topology_changed() { return false; } 2762 2763 size_t os::numa_get_groups_num() { 2764 int max_node = Linux::numa_max_node(); 2765 return max_node > 0 ? max_node + 1 : 1; 2766 } 2767 2768 int os::numa_get_group_id() { 2769 int cpu_id = Linux::sched_getcpu(); 2770 if (cpu_id != -1) { 2771 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2772 if (lgrp_id != -1) { 2773 return lgrp_id; 2774 } 2775 } 2776 return 0; 2777 } 2778 2779 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2780 for (size_t i = 0; i < size; i++) { 2781 ids[i] = i; 2782 } 2783 return size; 2784 } 2785 2786 bool os::get_page_info(char *start, page_info* info) { 2787 return false; 2788 } 2789 2790 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2791 page_info* page_found) { 2792 return end; 2793 } 2794 2795 2796 int os::Linux::sched_getcpu_syscall(void) { 2797 unsigned int cpu; 2798 int retval = -1; 2799 2800 #if defined(IA32) 2801 #ifndef SYS_getcpu 2802 #define SYS_getcpu 318 2803 #endif 2804 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2805 #elif defined(AMD64) 2806 // Unfortunately we have to bring all these macros here from vsyscall.h 2807 // to be able to compile on old linuxes. 2808 #define __NR_vgetcpu 2 2809 #define VSYSCALL_START (-10UL << 20) 2810 #define VSYSCALL_SIZE 1024 2811 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2812 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2813 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2814 retval = vgetcpu(&cpu, NULL, NULL); 2815 #endif 2816 2817 return (retval == -1) ? retval : cpu; 2818 } 2819 2820 // Something to do with the numa-aware allocator needs these symbols 2821 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2822 extern "C" JNIEXPORT void numa_error(char *where) { } 2823 extern "C" JNIEXPORT int fork1() { return fork(); } 2824 2825 2826 // If we are running with libnuma version > 2, then we should 2827 // be trying to use symbols with versions 1.1 2828 // If we are running with earlier version, which did not have symbol versions, 2829 // we should use the base version. 2830 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2831 void *f = dlvsym(handle, name, "libnuma_1.1"); 2832 if (f == NULL) { 2833 f = dlsym(handle, name); 2834 } 2835 return f; 2836 } 2837 2838 bool os::Linux::libnuma_init() { 2839 // sched_getcpu() should be in libc. 2840 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2841 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2842 2843 // If it's not, try a direct syscall. 2844 if (sched_getcpu() == -1) { 2845 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2846 (void*)&sched_getcpu_syscall)); 2847 } 2848 2849 if (sched_getcpu() != -1) { // Does it work? 2850 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2851 if (handle != NULL) { 2852 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2853 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2854 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2855 libnuma_dlsym(handle, "numa_max_node"))); 2856 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2857 libnuma_dlsym(handle, "numa_available"))); 2858 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2859 libnuma_dlsym(handle, "numa_tonode_memory"))); 2860 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2861 libnuma_dlsym(handle, "numa_interleave_memory"))); 2862 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2863 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2864 2865 2866 if (numa_available() != -1) { 2867 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2868 // Create a cpu -> node mapping 2869 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2870 rebuild_cpu_to_node_map(); 2871 return true; 2872 } 2873 } 2874 } 2875 return false; 2876 } 2877 2878 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2879 // The table is later used in get_node_by_cpu(). 2880 void os::Linux::rebuild_cpu_to_node_map() { 2881 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2882 // in libnuma (possible values are starting from 16, 2883 // and continuing up with every other power of 2, but less 2884 // than the maximum number of CPUs supported by kernel), and 2885 // is a subject to change (in libnuma version 2 the requirements 2886 // are more reasonable) we'll just hardcode the number they use 2887 // in the library. 2888 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2889 2890 size_t cpu_num = os::active_processor_count(); 2891 size_t cpu_map_size = NCPUS / BitsPerCLong; 2892 size_t cpu_map_valid_size = 2893 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2894 2895 cpu_to_node()->clear(); 2896 cpu_to_node()->at_grow(cpu_num - 1); 2897 size_t node_num = numa_get_groups_num(); 2898 2899 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2900 for (size_t i = 0; i < node_num; i++) { 2901 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2902 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2903 if (cpu_map[j] != 0) { 2904 for (size_t k = 0; k < BitsPerCLong; k++) { 2905 if (cpu_map[j] & (1UL << k)) { 2906 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2907 } 2908 } 2909 } 2910 } 2911 } 2912 } 2913 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2914 } 2915 2916 int os::Linux::get_node_by_cpu(int cpu_id) { 2917 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2918 return cpu_to_node()->at(cpu_id); 2919 } 2920 return -1; 2921 } 2922 2923 GrowableArray<int>* os::Linux::_cpu_to_node; 2924 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2925 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2926 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2927 os::Linux::numa_available_func_t os::Linux::_numa_available; 2928 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2929 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2930 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2931 unsigned long* os::Linux::_numa_all_nodes; 2932 2933 bool os::pd_uncommit_memory(char* addr, size_t size) { 2934 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2935 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2936 return res != (uintptr_t) MAP_FAILED; 2937 } 2938 2939 static address get_stack_commited_bottom(address bottom, size_t size) { 2940 address nbot = bottom; 2941 address ntop = bottom + size; 2942 2943 size_t page_sz = os::vm_page_size(); 2944 unsigned pages = size / page_sz; 2945 2946 unsigned char vec[1]; 2947 unsigned imin = 1, imax = pages + 1, imid; 2948 int mincore_return_value = 0; 2949 2950 assert(imin <= imax, "Unexpected page size"); 2951 2952 while (imin < imax) { 2953 imid = (imax + imin) / 2; 2954 nbot = ntop - (imid * page_sz); 2955 2956 // Use a trick with mincore to check whether the page is mapped or not. 2957 // mincore sets vec to 1 if page resides in memory and to 0 if page 2958 // is swapped output but if page we are asking for is unmapped 2959 // it returns -1,ENOMEM 2960 mincore_return_value = mincore(nbot, page_sz, vec); 2961 2962 if (mincore_return_value == -1) { 2963 // Page is not mapped go up 2964 // to find first mapped page 2965 if (errno != EAGAIN) { 2966 assert(errno == ENOMEM, "Unexpected mincore errno"); 2967 imax = imid; 2968 } 2969 } else { 2970 // Page is mapped go down 2971 // to find first not mapped page 2972 imin = imid + 1; 2973 } 2974 } 2975 2976 nbot = nbot + page_sz; 2977 2978 // Adjust stack bottom one page up if last checked page is not mapped 2979 if (mincore_return_value == -1) { 2980 nbot = nbot + page_sz; 2981 } 2982 2983 return nbot; 2984 } 2985 2986 2987 // Linux uses a growable mapping for the stack, and if the mapping for 2988 // the stack guard pages is not removed when we detach a thread the 2989 // stack cannot grow beyond the pages where the stack guard was 2990 // mapped. If at some point later in the process the stack expands to 2991 // that point, the Linux kernel cannot expand the stack any further 2992 // because the guard pages are in the way, and a segfault occurs. 2993 // 2994 // However, it's essential not to split the stack region by unmapping 2995 // a region (leaving a hole) that's already part of the stack mapping, 2996 // so if the stack mapping has already grown beyond the guard pages at 2997 // the time we create them, we have to truncate the stack mapping. 2998 // So, we need to know the extent of the stack mapping when 2999 // create_stack_guard_pages() is called. 3000 3001 // We only need this for stacks that are growable: at the time of 3002 // writing thread stacks don't use growable mappings (i.e. those 3003 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3004 // only applies to the main thread. 3005 3006 // If the (growable) stack mapping already extends beyond the point 3007 // where we're going to put our guard pages, truncate the mapping at 3008 // that point by munmap()ping it. This ensures that when we later 3009 // munmap() the guard pages we don't leave a hole in the stack 3010 // mapping. This only affects the main/initial thread 3011 3012 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3013 if (os::Linux::is_initial_thread()) { 3014 // As we manually grow stack up to bottom inside create_attached_thread(), 3015 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3016 // we don't need to do anything special. 3017 // Check it first, before calling heavy function. 3018 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3019 unsigned char vec[1]; 3020 3021 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3022 // Fallback to slow path on all errors, including EAGAIN 3023 stack_extent = (uintptr_t) get_stack_commited_bottom( 3024 os::Linux::initial_thread_stack_bottom(), 3025 (size_t)addr - stack_extent); 3026 } 3027 3028 if (stack_extent < (uintptr_t)addr) { 3029 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3030 } 3031 } 3032 3033 return os::commit_memory(addr, size, !ExecMem); 3034 } 3035 3036 // If this is a growable mapping, remove the guard pages entirely by 3037 // munmap()ping them. If not, just call uncommit_memory(). This only 3038 // affects the main/initial thread, but guard against future OS changes 3039 // It's safe to always unmap guard pages for initial thread because we 3040 // always place it right after end of the mapped region 3041 3042 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3043 uintptr_t stack_extent, stack_base; 3044 3045 if (os::Linux::is_initial_thread()) { 3046 return ::munmap(addr, size) == 0; 3047 } 3048 3049 return os::uncommit_memory(addr, size); 3050 } 3051 3052 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3053 // at 'requested_addr'. If there are existing memory mappings at the same 3054 // location, however, they will be overwritten. If 'fixed' is false, 3055 // 'requested_addr' is only treated as a hint, the return value may or 3056 // may not start from the requested address. Unlike Linux mmap(), this 3057 // function returns NULL to indicate failure. 3058 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3059 char * addr; 3060 int flags; 3061 3062 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3063 if (fixed) { 3064 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3065 flags |= MAP_FIXED; 3066 } 3067 3068 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3069 // touch an uncommitted page. Otherwise, the read/write might 3070 // succeed if we have enough swap space to back the physical page. 3071 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3072 flags, -1, 0); 3073 3074 return addr == MAP_FAILED ? NULL : addr; 3075 } 3076 3077 static int anon_munmap(char * addr, size_t size) { 3078 return ::munmap(addr, size) == 0; 3079 } 3080 3081 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3082 size_t alignment_hint) { 3083 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3084 } 3085 3086 bool os::pd_release_memory(char* addr, size_t size) { 3087 return anon_munmap(addr, size); 3088 } 3089 3090 static bool linux_mprotect(char* addr, size_t size, int prot) { 3091 // Linux wants the mprotect address argument to be page aligned. 3092 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3093 3094 // According to SUSv3, mprotect() should only be used with mappings 3095 // established by mmap(), and mmap() always maps whole pages. Unaligned 3096 // 'addr' likely indicates problem in the VM (e.g. trying to change 3097 // protection of malloc'ed or statically allocated memory). Check the 3098 // caller if you hit this assert. 3099 assert(addr == bottom, "sanity check"); 3100 3101 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3102 return ::mprotect(bottom, size, prot) == 0; 3103 } 3104 3105 // Set protections specified 3106 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3107 bool is_committed) { 3108 unsigned int p = 0; 3109 switch (prot) { 3110 case MEM_PROT_NONE: p = PROT_NONE; break; 3111 case MEM_PROT_READ: p = PROT_READ; break; 3112 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3113 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3114 default: 3115 ShouldNotReachHere(); 3116 } 3117 // is_committed is unused. 3118 return linux_mprotect(addr, bytes, p); 3119 } 3120 3121 bool os::guard_memory(char* addr, size_t size) { 3122 return linux_mprotect(addr, size, PROT_NONE); 3123 } 3124 3125 bool os::unguard_memory(char* addr, size_t size) { 3126 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3127 } 3128 3129 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3130 size_t page_size) { 3131 bool result = false; 3132 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3133 MAP_ANONYMOUS|MAP_PRIVATE, 3134 -1, 0); 3135 if (p != MAP_FAILED) { 3136 void *aligned_p = align_ptr_up(p, page_size); 3137 3138 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3139 3140 munmap(p, page_size * 2); 3141 } 3142 3143 if (warn && !result) { 3144 warning("TransparentHugePages is not supported by the operating system."); 3145 } 3146 3147 return result; 3148 } 3149 3150 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3151 bool result = false; 3152 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3153 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3154 -1, 0); 3155 3156 if (p != MAP_FAILED) { 3157 // We don't know if this really is a huge page or not. 3158 FILE *fp = fopen("/proc/self/maps", "r"); 3159 if (fp) { 3160 while (!feof(fp)) { 3161 char chars[257]; 3162 long x = 0; 3163 if (fgets(chars, sizeof(chars), fp)) { 3164 if (sscanf(chars, "%lx-%*x", &x) == 1 3165 && x == (long)p) { 3166 if (strstr (chars, "hugepage")) { 3167 result = true; 3168 break; 3169 } 3170 } 3171 } 3172 } 3173 fclose(fp); 3174 } 3175 munmap(p, page_size); 3176 } 3177 3178 if (warn && !result) { 3179 warning("HugeTLBFS is not supported by the operating system."); 3180 } 3181 3182 return result; 3183 } 3184 3185 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3186 // 3187 // From the coredump_filter documentation: 3188 // 3189 // - (bit 0) anonymous private memory 3190 // - (bit 1) anonymous shared memory 3191 // - (bit 2) file-backed private memory 3192 // - (bit 3) file-backed shared memory 3193 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3194 // effective only if the bit 2 is cleared) 3195 // - (bit 5) hugetlb private memory 3196 // - (bit 6) hugetlb shared memory 3197 // 3198 static void set_coredump_filter(void) { 3199 FILE *f; 3200 long cdm; 3201 3202 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3203 return; 3204 } 3205 3206 if (fscanf(f, "%lx", &cdm) != 1) { 3207 fclose(f); 3208 return; 3209 } 3210 3211 rewind(f); 3212 3213 if ((cdm & LARGEPAGES_BIT) == 0) { 3214 cdm |= LARGEPAGES_BIT; 3215 fprintf(f, "%#lx", cdm); 3216 } 3217 3218 fclose(f); 3219 } 3220 3221 // Large page support 3222 3223 static size_t _large_page_size = 0; 3224 3225 size_t os::Linux::find_large_page_size() { 3226 size_t large_page_size = 0; 3227 3228 // large_page_size on Linux is used to round up heap size. x86 uses either 3229 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3230 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3231 // page as large as 256M. 3232 // 3233 // Here we try to figure out page size by parsing /proc/meminfo and looking 3234 // for a line with the following format: 3235 // Hugepagesize: 2048 kB 3236 // 3237 // If we can't determine the value (e.g. /proc is not mounted, or the text 3238 // format has been changed), we'll use the largest page size supported by 3239 // the processor. 3240 3241 #ifndef ZERO 3242 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3243 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M); 3244 #endif // ZERO 3245 3246 FILE *fp = fopen("/proc/meminfo", "r"); 3247 if (fp) { 3248 while (!feof(fp)) { 3249 int x = 0; 3250 char buf[16]; 3251 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3252 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3253 large_page_size = x * K; 3254 break; 3255 } 3256 } else { 3257 // skip to next line 3258 for (;;) { 3259 int ch = fgetc(fp); 3260 if (ch == EOF || ch == (int)'\n') break; 3261 } 3262 } 3263 } 3264 fclose(fp); 3265 } 3266 3267 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3268 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3269 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3270 proper_unit_for_byte_size(large_page_size)); 3271 } 3272 3273 return large_page_size; 3274 } 3275 3276 size_t os::Linux::setup_large_page_size() { 3277 _large_page_size = Linux::find_large_page_size(); 3278 const size_t default_page_size = (size_t)Linux::page_size(); 3279 if (_large_page_size > default_page_size) { 3280 _page_sizes[0] = _large_page_size; 3281 _page_sizes[1] = default_page_size; 3282 _page_sizes[2] = 0; 3283 } 3284 3285 return _large_page_size; 3286 } 3287 3288 bool os::Linux::setup_large_page_type(size_t page_size) { 3289 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3290 FLAG_IS_DEFAULT(UseSHM) && 3291 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3292 3293 // The type of large pages has not been specified by the user. 3294 3295 // Try UseHugeTLBFS and then UseSHM. 3296 UseHugeTLBFS = UseSHM = true; 3297 3298 // Don't try UseTransparentHugePages since there are known 3299 // performance issues with it turned on. This might change in the future. 3300 UseTransparentHugePages = false; 3301 } 3302 3303 if (UseTransparentHugePages) { 3304 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3305 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3306 UseHugeTLBFS = false; 3307 UseSHM = false; 3308 return true; 3309 } 3310 UseTransparentHugePages = false; 3311 } 3312 3313 if (UseHugeTLBFS) { 3314 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3315 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3316 UseSHM = false; 3317 return true; 3318 } 3319 UseHugeTLBFS = false; 3320 } 3321 3322 return UseSHM; 3323 } 3324 3325 void os::large_page_init() { 3326 if (!UseLargePages && 3327 !UseTransparentHugePages && 3328 !UseHugeTLBFS && 3329 !UseSHM) { 3330 // Not using large pages. 3331 return; 3332 } 3333 3334 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3335 // The user explicitly turned off large pages. 3336 // Ignore the rest of the large pages flags. 3337 UseTransparentHugePages = false; 3338 UseHugeTLBFS = false; 3339 UseSHM = false; 3340 return; 3341 } 3342 3343 size_t large_page_size = Linux::setup_large_page_size(); 3344 UseLargePages = Linux::setup_large_page_type(large_page_size); 3345 3346 set_coredump_filter(); 3347 } 3348 3349 #ifndef SHM_HUGETLB 3350 #define SHM_HUGETLB 04000 3351 #endif 3352 3353 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3354 char* req_addr, bool exec) { 3355 // "exec" is passed in but not used. Creating the shared image for 3356 // the code cache doesn't have an SHM_X executable permission to check. 3357 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3358 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3359 3360 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3361 return NULL; // Fallback to small pages. 3362 } 3363 3364 key_t key = IPC_PRIVATE; 3365 char *addr; 3366 3367 bool warn_on_failure = UseLargePages && 3368 (!FLAG_IS_DEFAULT(UseLargePages) || 3369 !FLAG_IS_DEFAULT(UseSHM) || 3370 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3371 char msg[128]; 3372 3373 // Create a large shared memory region to attach to based on size. 3374 // Currently, size is the total size of the heap 3375 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3376 if (shmid == -1) { 3377 // Possible reasons for shmget failure: 3378 // 1. shmmax is too small for Java heap. 3379 // > check shmmax value: cat /proc/sys/kernel/shmmax 3380 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3381 // 2. not enough large page memory. 3382 // > check available large pages: cat /proc/meminfo 3383 // > increase amount of large pages: 3384 // echo new_value > /proc/sys/vm/nr_hugepages 3385 // Note 1: different Linux may use different name for this property, 3386 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3387 // Note 2: it's possible there's enough physical memory available but 3388 // they are so fragmented after a long run that they can't 3389 // coalesce into large pages. Try to reserve large pages when 3390 // the system is still "fresh". 3391 if (warn_on_failure) { 3392 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3393 warning("%s", msg); 3394 } 3395 return NULL; 3396 } 3397 3398 // attach to the region 3399 addr = (char*)shmat(shmid, req_addr, 0); 3400 int err = errno; 3401 3402 // Remove shmid. If shmat() is successful, the actual shared memory segment 3403 // will be deleted when it's detached by shmdt() or when the process 3404 // terminates. If shmat() is not successful this will remove the shared 3405 // segment immediately. 3406 shmctl(shmid, IPC_RMID, NULL); 3407 3408 if ((intptr_t)addr == -1) { 3409 if (warn_on_failure) { 3410 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3411 warning("%s", msg); 3412 } 3413 return NULL; 3414 } 3415 3416 return addr; 3417 } 3418 3419 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3420 int error) { 3421 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3422 3423 bool warn_on_failure = UseLargePages && 3424 (!FLAG_IS_DEFAULT(UseLargePages) || 3425 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3426 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3427 3428 if (warn_on_failure) { 3429 char msg[128]; 3430 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3431 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3432 warning("%s", msg); 3433 } 3434 } 3435 3436 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3437 char* req_addr, 3438 bool exec) { 3439 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3440 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3441 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3442 3443 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3444 char* addr = (char*)::mmap(req_addr, bytes, prot, 3445 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3446 -1, 0); 3447 3448 if (addr == MAP_FAILED) { 3449 warn_on_large_pages_failure(req_addr, bytes, errno); 3450 return NULL; 3451 } 3452 3453 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3454 3455 return addr; 3456 } 3457 3458 // Helper for os::Linux::reserve_memory_special_huge_tlbfs_mixed(). 3459 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3460 // (req_addr != NULL) or with a given alignment. 3461 // - bytes shall be a multiple of alignment. 3462 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3463 // - alignment sets the alignment at which memory shall be allocated. 3464 // It must be a multiple of allocation granularity. 3465 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3466 // req_addr or NULL. 3467 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3468 3469 size_t extra_size = bytes; 3470 if (req_addr == NULL && alignment > 0) { 3471 extra_size += alignment; 3472 } 3473 3474 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3475 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3476 -1, 0); 3477 if (start == MAP_FAILED) { 3478 start = NULL; 3479 } else { 3480 if (req_addr != NULL) { 3481 if (start != req_addr) { 3482 ::munmap(start, extra_size); 3483 start = NULL; 3484 } 3485 } else { 3486 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3487 char* const end_aligned = start_aligned + bytes; 3488 char* const end = start + extra_size; 3489 if (start_aligned > start) { 3490 ::munmap(start, start_aligned - start); 3491 } 3492 if (end_aligned < end) { 3493 ::munmap(end_aligned, end - end_aligned); 3494 } 3495 start = start_aligned; 3496 } 3497 } 3498 return start; 3499 3500 } 3501 3502 // Reserve memory using mmap(MAP_HUGETLB). 3503 // - bytes shall be a multiple of alignment. 3504 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3505 // - alignment sets the alignment at which memory shall be allocated. 3506 // It must be a multiple of allocation granularity. 3507 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3508 // req_addr or NULL. 3509 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3510 size_t alignment, 3511 char* req_addr, 3512 bool exec) { 3513 size_t large_page_size = os::large_page_size(); 3514 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3515 3516 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3517 assert(is_size_aligned(bytes, alignment), "Must be"); 3518 3519 // First reserve - but not commit - the address range in small pages. 3520 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3521 3522 if (start == NULL) { 3523 return NULL; 3524 } 3525 3526 assert(is_ptr_aligned(start, alignment), "Must be"); 3527 3528 char* end = start + bytes; 3529 3530 // Find the regions of the allocated chunk that can be promoted to large pages. 3531 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3532 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3533 3534 size_t lp_bytes = lp_end - lp_start; 3535 3536 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3537 3538 if (lp_bytes == 0) { 3539 // The mapped region doesn't even span the start and the end of a large page. 3540 // Fall back to allocate a non-special area. 3541 ::munmap(start, end - start); 3542 return NULL; 3543 } 3544 3545 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3546 3547 void* result; 3548 3549 // Commit small-paged leading area. 3550 if (start != lp_start) { 3551 result = ::mmap(start, lp_start - start, prot, 3552 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3553 -1, 0); 3554 if (result == MAP_FAILED) { 3555 ::munmap(lp_start, end - lp_start); 3556 return NULL; 3557 } 3558 } 3559 3560 // Commit large-paged area. 3561 result = ::mmap(lp_start, lp_bytes, prot, 3562 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3563 -1, 0); 3564 if (result == MAP_FAILED) { 3565 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3566 // If the mmap above fails, the large pages region will be unmapped and we 3567 // have regions before and after with small pages. Release these regions. 3568 // 3569 // | mapped | unmapped | mapped | 3570 // ^ ^ ^ ^ 3571 // start lp_start lp_end end 3572 // 3573 ::munmap(start, lp_start - start); 3574 ::munmap(lp_end, end - lp_end); 3575 return NULL; 3576 } 3577 3578 // Commit small-paged trailing area. 3579 if (lp_end != end) { 3580 result = ::mmap(lp_end, end - lp_end, prot, 3581 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3582 -1, 0); 3583 if (result == MAP_FAILED) { 3584 ::munmap(start, lp_end - start); 3585 return NULL; 3586 } 3587 } 3588 3589 return start; 3590 } 3591 3592 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3593 size_t alignment, 3594 char* req_addr, 3595 bool exec) { 3596 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3597 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3598 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3599 assert(is_power_of_2(os::large_page_size()), "Must be"); 3600 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3601 3602 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3603 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3604 } else { 3605 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3606 } 3607 } 3608 3609 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3610 char* req_addr, bool exec) { 3611 assert(UseLargePages, "only for large pages"); 3612 3613 char* addr; 3614 if (UseSHM) { 3615 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3616 } else { 3617 assert(UseHugeTLBFS, "must be"); 3618 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3619 } 3620 3621 if (addr != NULL) { 3622 if (UseNUMAInterleaving) { 3623 numa_make_global(addr, bytes); 3624 } 3625 3626 // The memory is committed 3627 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3628 } 3629 3630 return addr; 3631 } 3632 3633 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3634 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3635 return shmdt(base) == 0; 3636 } 3637 3638 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3639 return pd_release_memory(base, bytes); 3640 } 3641 3642 bool os::release_memory_special(char* base, size_t bytes) { 3643 bool res; 3644 if (MemTracker::tracking_level() > NMT_minimal) { 3645 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3646 res = os::Linux::release_memory_special_impl(base, bytes); 3647 if (res) { 3648 tkr.record((address)base, bytes); 3649 } 3650 3651 } else { 3652 res = os::Linux::release_memory_special_impl(base, bytes); 3653 } 3654 return res; 3655 } 3656 3657 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3658 assert(UseLargePages, "only for large pages"); 3659 bool res; 3660 3661 if (UseSHM) { 3662 res = os::Linux::release_memory_special_shm(base, bytes); 3663 } else { 3664 assert(UseHugeTLBFS, "must be"); 3665 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3666 } 3667 return res; 3668 } 3669 3670 size_t os::large_page_size() { 3671 return _large_page_size; 3672 } 3673 3674 // With SysV SHM the entire memory region must be allocated as shared 3675 // memory. 3676 // HugeTLBFS allows application to commit large page memory on demand. 3677 // However, when committing memory with HugeTLBFS fails, the region 3678 // that was supposed to be committed will lose the old reservation 3679 // and allow other threads to steal that memory region. Because of this 3680 // behavior we can't commit HugeTLBFS memory. 3681 bool os::can_commit_large_page_memory() { 3682 return UseTransparentHugePages; 3683 } 3684 3685 bool os::can_execute_large_page_memory() { 3686 return UseTransparentHugePages || UseHugeTLBFS; 3687 } 3688 3689 // Reserve memory at an arbitrary address, only if that area is 3690 // available (and not reserved for something else). 3691 3692 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3693 const int max_tries = 10; 3694 char* base[max_tries]; 3695 size_t size[max_tries]; 3696 const size_t gap = 0x000000; 3697 3698 // Assert only that the size is a multiple of the page size, since 3699 // that's all that mmap requires, and since that's all we really know 3700 // about at this low abstraction level. If we need higher alignment, 3701 // we can either pass an alignment to this method or verify alignment 3702 // in one of the methods further up the call chain. See bug 5044738. 3703 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3704 3705 // Repeatedly allocate blocks until the block is allocated at the 3706 // right spot. 3707 3708 // Linux mmap allows caller to pass an address as hint; give it a try first, 3709 // if kernel honors the hint then we can return immediately. 3710 char * addr = anon_mmap(requested_addr, bytes, false); 3711 if (addr == requested_addr) { 3712 return requested_addr; 3713 } 3714 3715 if (addr != NULL) { 3716 // mmap() is successful but it fails to reserve at the requested address 3717 anon_munmap(addr, bytes); 3718 } 3719 3720 int i; 3721 for (i = 0; i < max_tries; ++i) { 3722 base[i] = reserve_memory(bytes); 3723 3724 if (base[i] != NULL) { 3725 // Is this the block we wanted? 3726 if (base[i] == requested_addr) { 3727 size[i] = bytes; 3728 break; 3729 } 3730 3731 // Does this overlap the block we wanted? Give back the overlapped 3732 // parts and try again. 3733 3734 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3735 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3736 unmap_memory(base[i], top_overlap); 3737 base[i] += top_overlap; 3738 size[i] = bytes - top_overlap; 3739 } else { 3740 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3741 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3742 unmap_memory(requested_addr, bottom_overlap); 3743 size[i] = bytes - bottom_overlap; 3744 } else { 3745 size[i] = bytes; 3746 } 3747 } 3748 } 3749 } 3750 3751 // Give back the unused reserved pieces. 3752 3753 for (int j = 0; j < i; ++j) { 3754 if (base[j] != NULL) { 3755 unmap_memory(base[j], size[j]); 3756 } 3757 } 3758 3759 if (i < max_tries) { 3760 return requested_addr; 3761 } else { 3762 return NULL; 3763 } 3764 } 3765 3766 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3767 return ::read(fd, buf, nBytes); 3768 } 3769 3770 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3771 return ::pread(fd, buf, nBytes, offset); 3772 } 3773 3774 // Short sleep, direct OS call. 3775 // 3776 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3777 // sched_yield(2) will actually give up the CPU: 3778 // 3779 // * Alone on this pariticular CPU, keeps running. 3780 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3781 // (pre 2.6.39). 3782 // 3783 // So calling this with 0 is an alternative. 3784 // 3785 void os::naked_short_sleep(jlong ms) { 3786 struct timespec req; 3787 3788 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3789 req.tv_sec = 0; 3790 if (ms > 0) { 3791 req.tv_nsec = (ms % 1000) * 1000000; 3792 } else { 3793 req.tv_nsec = 1; 3794 } 3795 3796 nanosleep(&req, NULL); 3797 3798 return; 3799 } 3800 3801 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3802 void os::infinite_sleep() { 3803 while (true) { // sleep forever ... 3804 ::sleep(100); // ... 100 seconds at a time 3805 } 3806 } 3807 3808 // Used to convert frequent JVM_Yield() to nops 3809 bool os::dont_yield() { 3810 return DontYieldALot; 3811 } 3812 3813 void os::naked_yield() { 3814 sched_yield(); 3815 } 3816 3817 //////////////////////////////////////////////////////////////////////////////// 3818 // thread priority support 3819 3820 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3821 // only supports dynamic priority, static priority must be zero. For real-time 3822 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3823 // However, for large multi-threaded applications, SCHED_RR is not only slower 3824 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3825 // of 5 runs - Sep 2005). 3826 // 3827 // The following code actually changes the niceness of kernel-thread/LWP. It 3828 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3829 // not the entire user process, and user level threads are 1:1 mapped to kernel 3830 // threads. It has always been the case, but could change in the future. For 3831 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3832 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3833 3834 int os::java_to_os_priority[CriticalPriority + 1] = { 3835 19, // 0 Entry should never be used 3836 3837 4, // 1 MinPriority 3838 3, // 2 3839 2, // 3 3840 3841 1, // 4 3842 0, // 5 NormPriority 3843 -1, // 6 3844 3845 -2, // 7 3846 -3, // 8 3847 -4, // 9 NearMaxPriority 3848 3849 -5, // 10 MaxPriority 3850 3851 -5 // 11 CriticalPriority 3852 }; 3853 3854 static int prio_init() { 3855 if (ThreadPriorityPolicy == 1) { 3856 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3857 // if effective uid is not root. Perhaps, a more elegant way of doing 3858 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3859 if (geteuid() != 0) { 3860 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3861 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3862 } 3863 ThreadPriorityPolicy = 0; 3864 } 3865 } 3866 if (UseCriticalJavaThreadPriority) { 3867 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3868 } 3869 return 0; 3870 } 3871 3872 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3873 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3874 3875 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3876 return (ret == 0) ? OS_OK : OS_ERR; 3877 } 3878 3879 OSReturn os::get_native_priority(const Thread* const thread, 3880 int *priority_ptr) { 3881 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3882 *priority_ptr = java_to_os_priority[NormPriority]; 3883 return OS_OK; 3884 } 3885 3886 errno = 0; 3887 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3888 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3889 } 3890 3891 // Hint to the underlying OS that a task switch would not be good. 3892 // Void return because it's a hint and can fail. 3893 void os::hint_no_preempt() {} 3894 3895 //////////////////////////////////////////////////////////////////////////////// 3896 // suspend/resume support 3897 3898 // the low-level signal-based suspend/resume support is a remnant from the 3899 // old VM-suspension that used to be for java-suspension, safepoints etc, 3900 // within hotspot. Now there is a single use-case for this: 3901 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3902 // that runs in the watcher thread. 3903 // The remaining code is greatly simplified from the more general suspension 3904 // code that used to be used. 3905 // 3906 // The protocol is quite simple: 3907 // - suspend: 3908 // - sends a signal to the target thread 3909 // - polls the suspend state of the osthread using a yield loop 3910 // - target thread signal handler (SR_handler) sets suspend state 3911 // and blocks in sigsuspend until continued 3912 // - resume: 3913 // - sets target osthread state to continue 3914 // - sends signal to end the sigsuspend loop in the SR_handler 3915 // 3916 // Note that the SR_lock plays no role in this suspend/resume protocol. 3917 3918 static void resume_clear_context(OSThread *osthread) { 3919 osthread->set_ucontext(NULL); 3920 osthread->set_siginfo(NULL); 3921 } 3922 3923 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3924 ucontext_t* context) { 3925 osthread->set_ucontext(context); 3926 osthread->set_siginfo(siginfo); 3927 } 3928 3929 // Handler function invoked when a thread's execution is suspended or 3930 // resumed. We have to be careful that only async-safe functions are 3931 // called here (Note: most pthread functions are not async safe and 3932 // should be avoided.) 3933 // 3934 // Note: sigwait() is a more natural fit than sigsuspend() from an 3935 // interface point of view, but sigwait() prevents the signal hander 3936 // from being run. libpthread would get very confused by not having 3937 // its signal handlers run and prevents sigwait()'s use with the 3938 // mutex granting granting signal. 3939 // 3940 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3941 // 3942 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3943 // Save and restore errno to avoid confusing native code with EINTR 3944 // after sigsuspend. 3945 int old_errno = errno; 3946 3947 Thread* thread = Thread::current(); 3948 OSThread* osthread = thread->osthread(); 3949 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3950 3951 os::SuspendResume::State current = osthread->sr.state(); 3952 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3953 suspend_save_context(osthread, siginfo, context); 3954 3955 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3956 os::SuspendResume::State state = osthread->sr.suspended(); 3957 if (state == os::SuspendResume::SR_SUSPENDED) { 3958 sigset_t suspend_set; // signals for sigsuspend() 3959 3960 // get current set of blocked signals and unblock resume signal 3961 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3962 sigdelset(&suspend_set, SR_signum); 3963 3964 sr_semaphore.signal(); 3965 // wait here until we are resumed 3966 while (1) { 3967 sigsuspend(&suspend_set); 3968 3969 os::SuspendResume::State result = osthread->sr.running(); 3970 if (result == os::SuspendResume::SR_RUNNING) { 3971 sr_semaphore.signal(); 3972 break; 3973 } 3974 } 3975 3976 } else if (state == os::SuspendResume::SR_RUNNING) { 3977 // request was cancelled, continue 3978 } else { 3979 ShouldNotReachHere(); 3980 } 3981 3982 resume_clear_context(osthread); 3983 } else if (current == os::SuspendResume::SR_RUNNING) { 3984 // request was cancelled, continue 3985 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3986 // ignore 3987 } else { 3988 // ignore 3989 } 3990 3991 errno = old_errno; 3992 } 3993 3994 3995 static int SR_initialize() { 3996 struct sigaction act; 3997 char *s; 3998 // Get signal number to use for suspend/resume 3999 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4000 int sig = ::strtol(s, 0, 10); 4001 if (sig > 0 || sig < _NSIG) { 4002 SR_signum = sig; 4003 } 4004 } 4005 4006 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4007 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4008 4009 sigemptyset(&SR_sigset); 4010 sigaddset(&SR_sigset, SR_signum); 4011 4012 // Set up signal handler for suspend/resume 4013 act.sa_flags = SA_RESTART|SA_SIGINFO; 4014 act.sa_handler = (void (*)(int)) SR_handler; 4015 4016 // SR_signum is blocked by default. 4017 // 4528190 - We also need to block pthread restart signal (32 on all 4018 // supported Linux platforms). Note that LinuxThreads need to block 4019 // this signal for all threads to work properly. So we don't have 4020 // to use hard-coded signal number when setting up the mask. 4021 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4022 4023 if (sigaction(SR_signum, &act, 0) == -1) { 4024 return -1; 4025 } 4026 4027 // Save signal flag 4028 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4029 return 0; 4030 } 4031 4032 static int sr_notify(OSThread* osthread) { 4033 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4034 assert_status(status == 0, status, "pthread_kill"); 4035 return status; 4036 } 4037 4038 // "Randomly" selected value for how long we want to spin 4039 // before bailing out on suspending a thread, also how often 4040 // we send a signal to a thread we want to resume 4041 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4042 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4043 4044 // returns true on success and false on error - really an error is fatal 4045 // but this seems the normal response to library errors 4046 static bool do_suspend(OSThread* osthread) { 4047 assert(osthread->sr.is_running(), "thread should be running"); 4048 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4049 4050 // mark as suspended and send signal 4051 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4052 // failed to switch, state wasn't running? 4053 ShouldNotReachHere(); 4054 return false; 4055 } 4056 4057 if (sr_notify(osthread) != 0) { 4058 ShouldNotReachHere(); 4059 } 4060 4061 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4062 while (true) { 4063 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4064 break; 4065 } else { 4066 // timeout 4067 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4068 if (cancelled == os::SuspendResume::SR_RUNNING) { 4069 return false; 4070 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4071 // make sure that we consume the signal on the semaphore as well 4072 sr_semaphore.wait(); 4073 break; 4074 } else { 4075 ShouldNotReachHere(); 4076 return false; 4077 } 4078 } 4079 } 4080 4081 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4082 return true; 4083 } 4084 4085 static void do_resume(OSThread* osthread) { 4086 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4087 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4088 4089 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4090 // failed to switch to WAKEUP_REQUEST 4091 ShouldNotReachHere(); 4092 return; 4093 } 4094 4095 while (true) { 4096 if (sr_notify(osthread) == 0) { 4097 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4098 if (osthread->sr.is_running()) { 4099 return; 4100 } 4101 } 4102 } else { 4103 ShouldNotReachHere(); 4104 } 4105 } 4106 4107 guarantee(osthread->sr.is_running(), "Must be running!"); 4108 } 4109 4110 /////////////////////////////////////////////////////////////////////////////////// 4111 // signal handling (except suspend/resume) 4112 4113 // This routine may be used by user applications as a "hook" to catch signals. 4114 // The user-defined signal handler must pass unrecognized signals to this 4115 // routine, and if it returns true (non-zero), then the signal handler must 4116 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4117 // routine will never retun false (zero), but instead will execute a VM panic 4118 // routine kill the process. 4119 // 4120 // If this routine returns false, it is OK to call it again. This allows 4121 // the user-defined signal handler to perform checks either before or after 4122 // the VM performs its own checks. Naturally, the user code would be making 4123 // a serious error if it tried to handle an exception (such as a null check 4124 // or breakpoint) that the VM was generating for its own correct operation. 4125 // 4126 // This routine may recognize any of the following kinds of signals: 4127 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4128 // It should be consulted by handlers for any of those signals. 4129 // 4130 // The caller of this routine must pass in the three arguments supplied 4131 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4132 // field of the structure passed to sigaction(). This routine assumes that 4133 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4134 // 4135 // Note that the VM will print warnings if it detects conflicting signal 4136 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4137 // 4138 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4139 siginfo_t* siginfo, 4140 void* ucontext, 4141 int abort_if_unrecognized); 4142 4143 void signalHandler(int sig, siginfo_t* info, void* uc) { 4144 assert(info != NULL && uc != NULL, "it must be old kernel"); 4145 int orig_errno = errno; // Preserve errno value over signal handler. 4146 JVM_handle_linux_signal(sig, info, uc, true); 4147 errno = orig_errno; 4148 } 4149 4150 4151 // This boolean allows users to forward their own non-matching signals 4152 // to JVM_handle_linux_signal, harmlessly. 4153 bool os::Linux::signal_handlers_are_installed = false; 4154 4155 // For signal-chaining 4156 struct sigaction os::Linux::sigact[MAXSIGNUM]; 4157 unsigned int os::Linux::sigs = 0; 4158 bool os::Linux::libjsig_is_loaded = false; 4159 typedef struct sigaction *(*get_signal_t)(int); 4160 get_signal_t os::Linux::get_signal_action = NULL; 4161 4162 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4163 struct sigaction *actp = NULL; 4164 4165 if (libjsig_is_loaded) { 4166 // Retrieve the old signal handler from libjsig 4167 actp = (*get_signal_action)(sig); 4168 } 4169 if (actp == NULL) { 4170 // Retrieve the preinstalled signal handler from jvm 4171 actp = get_preinstalled_handler(sig); 4172 } 4173 4174 return actp; 4175 } 4176 4177 static bool call_chained_handler(struct sigaction *actp, int sig, 4178 siginfo_t *siginfo, void *context) { 4179 // Call the old signal handler 4180 if (actp->sa_handler == SIG_DFL) { 4181 // It's more reasonable to let jvm treat it as an unexpected exception 4182 // instead of taking the default action. 4183 return false; 4184 } else if (actp->sa_handler != SIG_IGN) { 4185 if ((actp->sa_flags & SA_NODEFER) == 0) { 4186 // automaticlly block the signal 4187 sigaddset(&(actp->sa_mask), sig); 4188 } 4189 4190 sa_handler_t hand; 4191 sa_sigaction_t sa; 4192 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4193 // retrieve the chained handler 4194 if (siginfo_flag_set) { 4195 sa = actp->sa_sigaction; 4196 } else { 4197 hand = actp->sa_handler; 4198 } 4199 4200 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4201 actp->sa_handler = SIG_DFL; 4202 } 4203 4204 // try to honor the signal mask 4205 sigset_t oset; 4206 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4207 4208 // call into the chained handler 4209 if (siginfo_flag_set) { 4210 (*sa)(sig, siginfo, context); 4211 } else { 4212 (*hand)(sig); 4213 } 4214 4215 // restore the signal mask 4216 pthread_sigmask(SIG_SETMASK, &oset, 0); 4217 } 4218 // Tell jvm's signal handler the signal is taken care of. 4219 return true; 4220 } 4221 4222 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4223 bool chained = false; 4224 // signal-chaining 4225 if (UseSignalChaining) { 4226 struct sigaction *actp = get_chained_signal_action(sig); 4227 if (actp != NULL) { 4228 chained = call_chained_handler(actp, sig, siginfo, context); 4229 } 4230 } 4231 return chained; 4232 } 4233 4234 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4235 if ((((unsigned int)1 << sig) & sigs) != 0) { 4236 return &sigact[sig]; 4237 } 4238 return NULL; 4239 } 4240 4241 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4242 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4243 sigact[sig] = oldAct; 4244 sigs |= (unsigned int)1 << sig; 4245 } 4246 4247 // for diagnostic 4248 int os::Linux::sigflags[MAXSIGNUM]; 4249 4250 int os::Linux::get_our_sigflags(int sig) { 4251 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4252 return sigflags[sig]; 4253 } 4254 4255 void os::Linux::set_our_sigflags(int sig, int flags) { 4256 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4257 sigflags[sig] = flags; 4258 } 4259 4260 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4261 // Check for overwrite. 4262 struct sigaction oldAct; 4263 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4264 4265 void* oldhand = oldAct.sa_sigaction 4266 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4267 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4268 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4269 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4270 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4271 if (AllowUserSignalHandlers || !set_installed) { 4272 // Do not overwrite; user takes responsibility to forward to us. 4273 return; 4274 } else if (UseSignalChaining) { 4275 // save the old handler in jvm 4276 save_preinstalled_handler(sig, oldAct); 4277 // libjsig also interposes the sigaction() call below and saves the 4278 // old sigaction on it own. 4279 } else { 4280 fatal("Encountered unexpected pre-existing sigaction handler " 4281 "%#lx for signal %d.", (long)oldhand, sig); 4282 } 4283 } 4284 4285 struct sigaction sigAct; 4286 sigfillset(&(sigAct.sa_mask)); 4287 sigAct.sa_handler = SIG_DFL; 4288 if (!set_installed) { 4289 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4290 } else { 4291 sigAct.sa_sigaction = signalHandler; 4292 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4293 } 4294 // Save flags, which are set by ours 4295 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4296 sigflags[sig] = sigAct.sa_flags; 4297 4298 int ret = sigaction(sig, &sigAct, &oldAct); 4299 assert(ret == 0, "check"); 4300 4301 void* oldhand2 = oldAct.sa_sigaction 4302 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4303 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4304 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4305 } 4306 4307 // install signal handlers for signals that HotSpot needs to 4308 // handle in order to support Java-level exception handling. 4309 4310 void os::Linux::install_signal_handlers() { 4311 if (!signal_handlers_are_installed) { 4312 signal_handlers_are_installed = true; 4313 4314 // signal-chaining 4315 typedef void (*signal_setting_t)(); 4316 signal_setting_t begin_signal_setting = NULL; 4317 signal_setting_t end_signal_setting = NULL; 4318 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4319 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4320 if (begin_signal_setting != NULL) { 4321 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4322 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4323 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4324 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4325 libjsig_is_loaded = true; 4326 assert(UseSignalChaining, "should enable signal-chaining"); 4327 } 4328 if (libjsig_is_loaded) { 4329 // Tell libjsig jvm is setting signal handlers 4330 (*begin_signal_setting)(); 4331 } 4332 4333 set_signal_handler(SIGSEGV, true); 4334 set_signal_handler(SIGPIPE, true); 4335 set_signal_handler(SIGBUS, true); 4336 set_signal_handler(SIGILL, true); 4337 set_signal_handler(SIGFPE, true); 4338 #if defined(PPC64) 4339 set_signal_handler(SIGTRAP, true); 4340 #endif 4341 set_signal_handler(SIGXFSZ, true); 4342 4343 if (libjsig_is_loaded) { 4344 // Tell libjsig jvm finishes setting signal handlers 4345 (*end_signal_setting)(); 4346 } 4347 4348 // We don't activate signal checker if libjsig is in place, we trust ourselves 4349 // and if UserSignalHandler is installed all bets are off. 4350 // Log that signal checking is off only if -verbose:jni is specified. 4351 if (CheckJNICalls) { 4352 if (libjsig_is_loaded) { 4353 if (PrintJNIResolving) { 4354 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4355 } 4356 check_signals = false; 4357 } 4358 if (AllowUserSignalHandlers) { 4359 if (PrintJNIResolving) { 4360 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4361 } 4362 check_signals = false; 4363 } 4364 } 4365 } 4366 } 4367 4368 // This is the fastest way to get thread cpu time on Linux. 4369 // Returns cpu time (user+sys) for any thread, not only for current. 4370 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4371 // It might work on 2.6.10+ with a special kernel/glibc patch. 4372 // For reference, please, see IEEE Std 1003.1-2004: 4373 // http://www.unix.org/single_unix_specification 4374 4375 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4376 struct timespec tp; 4377 int rc = os::Linux::clock_gettime(clockid, &tp); 4378 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4379 4380 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4381 } 4382 4383 ///// 4384 // glibc on Linux platform uses non-documented flag 4385 // to indicate, that some special sort of signal 4386 // trampoline is used. 4387 // We will never set this flag, and we should 4388 // ignore this flag in our diagnostic 4389 #ifdef SIGNIFICANT_SIGNAL_MASK 4390 #undef SIGNIFICANT_SIGNAL_MASK 4391 #endif 4392 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4393 4394 static const char* get_signal_handler_name(address handler, 4395 char* buf, int buflen) { 4396 int offset; 4397 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4398 if (found) { 4399 // skip directory names 4400 const char *p1, *p2; 4401 p1 = buf; 4402 size_t len = strlen(os::file_separator()); 4403 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4404 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4405 } else { 4406 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4407 } 4408 return buf; 4409 } 4410 4411 static void print_signal_handler(outputStream* st, int sig, 4412 char* buf, size_t buflen) { 4413 struct sigaction sa; 4414 4415 sigaction(sig, NULL, &sa); 4416 4417 // See comment for SIGNIFICANT_SIGNAL_MASK define 4418 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4419 4420 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4421 4422 address handler = (sa.sa_flags & SA_SIGINFO) 4423 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4424 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4425 4426 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4427 st->print("SIG_DFL"); 4428 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4429 st->print("SIG_IGN"); 4430 } else { 4431 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4432 } 4433 4434 st->print(", sa_mask[0]="); 4435 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4436 4437 address rh = VMError::get_resetted_sighandler(sig); 4438 // May be, handler was resetted by VMError? 4439 if (rh != NULL) { 4440 handler = rh; 4441 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4442 } 4443 4444 st->print(", sa_flags="); 4445 os::Posix::print_sa_flags(st, sa.sa_flags); 4446 4447 // Check: is it our handler? 4448 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4449 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4450 // It is our signal handler 4451 // check for flags, reset system-used one! 4452 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4453 st->print( 4454 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4455 os::Linux::get_our_sigflags(sig)); 4456 } 4457 } 4458 st->cr(); 4459 } 4460 4461 4462 #define DO_SIGNAL_CHECK(sig) \ 4463 do { \ 4464 if (!sigismember(&check_signal_done, sig)) { \ 4465 os::Linux::check_signal_handler(sig); \ 4466 } \ 4467 } while (0) 4468 4469 // This method is a periodic task to check for misbehaving JNI applications 4470 // under CheckJNI, we can add any periodic checks here 4471 4472 void os::run_periodic_checks() { 4473 if (check_signals == false) return; 4474 4475 // SEGV and BUS if overridden could potentially prevent 4476 // generation of hs*.log in the event of a crash, debugging 4477 // such a case can be very challenging, so we absolutely 4478 // check the following for a good measure: 4479 DO_SIGNAL_CHECK(SIGSEGV); 4480 DO_SIGNAL_CHECK(SIGILL); 4481 DO_SIGNAL_CHECK(SIGFPE); 4482 DO_SIGNAL_CHECK(SIGBUS); 4483 DO_SIGNAL_CHECK(SIGPIPE); 4484 DO_SIGNAL_CHECK(SIGXFSZ); 4485 #if defined(PPC64) 4486 DO_SIGNAL_CHECK(SIGTRAP); 4487 #endif 4488 4489 // ReduceSignalUsage allows the user to override these handlers 4490 // see comments at the very top and jvm_solaris.h 4491 if (!ReduceSignalUsage) { 4492 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4493 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4494 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4495 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4496 } 4497 4498 DO_SIGNAL_CHECK(SR_signum); 4499 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4500 } 4501 4502 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4503 4504 static os_sigaction_t os_sigaction = NULL; 4505 4506 void os::Linux::check_signal_handler(int sig) { 4507 char buf[O_BUFLEN]; 4508 address jvmHandler = NULL; 4509 4510 4511 struct sigaction act; 4512 if (os_sigaction == NULL) { 4513 // only trust the default sigaction, in case it has been interposed 4514 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4515 if (os_sigaction == NULL) return; 4516 } 4517 4518 os_sigaction(sig, (struct sigaction*)NULL, &act); 4519 4520 4521 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4522 4523 address thisHandler = (act.sa_flags & SA_SIGINFO) 4524 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4525 : CAST_FROM_FN_PTR(address, act.sa_handler); 4526 4527 4528 switch (sig) { 4529 case SIGSEGV: 4530 case SIGBUS: 4531 case SIGFPE: 4532 case SIGPIPE: 4533 case SIGILL: 4534 case SIGXFSZ: 4535 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4536 break; 4537 4538 case SHUTDOWN1_SIGNAL: 4539 case SHUTDOWN2_SIGNAL: 4540 case SHUTDOWN3_SIGNAL: 4541 case BREAK_SIGNAL: 4542 jvmHandler = (address)user_handler(); 4543 break; 4544 4545 case INTERRUPT_SIGNAL: 4546 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4547 break; 4548 4549 default: 4550 if (sig == SR_signum) { 4551 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4552 } else { 4553 return; 4554 } 4555 break; 4556 } 4557 4558 if (thisHandler != jvmHandler) { 4559 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4560 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4561 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4562 // No need to check this sig any longer 4563 sigaddset(&check_signal_done, sig); 4564 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4565 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4566 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4567 exception_name(sig, buf, O_BUFLEN)); 4568 } 4569 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4570 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4571 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4572 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4573 // No need to check this sig any longer 4574 sigaddset(&check_signal_done, sig); 4575 } 4576 4577 // Dump all the signal 4578 if (sigismember(&check_signal_done, sig)) { 4579 print_signal_handlers(tty, buf, O_BUFLEN); 4580 } 4581 } 4582 4583 extern void report_error(char* file_name, int line_no, char* title, 4584 char* format, ...); 4585 4586 extern bool signal_name(int signo, char* buf, size_t len); 4587 4588 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4589 if (0 < exception_code && exception_code <= SIGRTMAX) { 4590 // signal 4591 if (!signal_name(exception_code, buf, size)) { 4592 jio_snprintf(buf, size, "SIG%d", exception_code); 4593 } 4594 return buf; 4595 } else { 4596 return NULL; 4597 } 4598 } 4599 4600 // this is called _before_ the most of global arguments have been parsed 4601 void os::init(void) { 4602 char dummy; // used to get a guess on initial stack address 4603 // first_hrtime = gethrtime(); 4604 4605 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4606 4607 init_random(1234567); 4608 4609 ThreadCritical::initialize(); 4610 4611 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4612 if (Linux::page_size() == -1) { 4613 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4614 strerror(errno)); 4615 } 4616 init_page_sizes((size_t) Linux::page_size()); 4617 4618 Linux::initialize_system_info(); 4619 4620 // main_thread points to the aboriginal thread 4621 Linux::_main_thread = pthread_self(); 4622 4623 Linux::clock_init(); 4624 initial_time_count = javaTimeNanos(); 4625 4626 // pthread_condattr initialization for monotonic clock 4627 int status; 4628 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4629 if ((status = pthread_condattr_init(_condattr)) != 0) { 4630 fatal("pthread_condattr_init: %s", strerror(status)); 4631 } 4632 // Only set the clock if CLOCK_MONOTONIC is available 4633 if (os::supports_monotonic_clock()) { 4634 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4635 if (status == EINVAL) { 4636 warning("Unable to use monotonic clock with relative timed-waits" \ 4637 " - changes to the time-of-day clock may have adverse affects"); 4638 } else { 4639 fatal("pthread_condattr_setclock: %s", strerror(status)); 4640 } 4641 } 4642 } 4643 // else it defaults to CLOCK_REALTIME 4644 4645 // If the pagesize of the VM is greater than 8K determine the appropriate 4646 // number of initial guard pages. The user can change this with the 4647 // command line arguments, if needed. 4648 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4649 StackYellowPages = 1; 4650 StackRedPages = 1; 4651 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4652 } 4653 4654 // retrieve entry point for pthread_setname_np 4655 Linux::_pthread_setname_np = 4656 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4657 4658 } 4659 4660 // To install functions for atexit system call 4661 extern "C" { 4662 static void perfMemory_exit_helper() { 4663 perfMemory_exit(); 4664 } 4665 } 4666 4667 // this is called _after_ the global arguments have been parsed 4668 jint os::init_2(void) { 4669 Linux::fast_thread_clock_init(); 4670 4671 // Allocate a single page and mark it as readable for safepoint polling 4672 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4673 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4674 4675 os::set_polling_page(polling_page); 4676 4677 #ifndef PRODUCT 4678 if (Verbose && PrintMiscellaneous) { 4679 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", 4680 (intptr_t)polling_page); 4681 } 4682 #endif 4683 4684 if (!UseMembar) { 4685 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4686 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4687 os::set_memory_serialize_page(mem_serialize_page); 4688 4689 #ifndef PRODUCT 4690 if (Verbose && PrintMiscellaneous) { 4691 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", 4692 (intptr_t)mem_serialize_page); 4693 } 4694 #endif 4695 } 4696 4697 // initialize suspend/resume support - must do this before signal_sets_init() 4698 if (SR_initialize() != 0) { 4699 perror("SR_initialize failed"); 4700 return JNI_ERR; 4701 } 4702 4703 Linux::signal_sets_init(); 4704 Linux::install_signal_handlers(); 4705 4706 // Check minimum allowable stack size for thread creation and to initialize 4707 // the java system classes, including StackOverflowError - depends on page 4708 // size. Add a page for compiler2 recursion in main thread. 4709 // Add in 2*BytesPerWord times page size to account for VM stack during 4710 // class initialization depending on 32 or 64 bit VM. 4711 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4712 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4713 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4714 4715 size_t threadStackSizeInBytes = ThreadStackSize * K; 4716 if (threadStackSizeInBytes != 0 && 4717 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4718 tty->print_cr("\nThe stack size specified is too small, " 4719 "Specify at least " SIZE_FORMAT "k", 4720 os::Linux::min_stack_allowed/ K); 4721 return JNI_ERR; 4722 } 4723 4724 // Make the stack size a multiple of the page size so that 4725 // the yellow/red zones can be guarded. 4726 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4727 vm_page_size())); 4728 4729 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4730 4731 #if defined(IA32) 4732 workaround_expand_exec_shield_cs_limit(); 4733 #endif 4734 4735 Linux::libpthread_init(); 4736 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4737 tty->print_cr("[HotSpot is running with %s, %s]\n", 4738 Linux::glibc_version(), Linux::libpthread_version()); 4739 } 4740 4741 if (UseNUMA) { 4742 if (!Linux::libnuma_init()) { 4743 UseNUMA = false; 4744 } else { 4745 if ((Linux::numa_max_node() < 1)) { 4746 // There's only one node(they start from 0), disable NUMA. 4747 UseNUMA = false; 4748 } 4749 } 4750 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4751 // we can make the adaptive lgrp chunk resizing work. If the user specified 4752 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4753 // disable adaptive resizing. 4754 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4755 if (FLAG_IS_DEFAULT(UseNUMA)) { 4756 UseNUMA = false; 4757 } else { 4758 if (FLAG_IS_DEFAULT(UseLargePages) && 4759 FLAG_IS_DEFAULT(UseSHM) && 4760 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4761 UseLargePages = false; 4762 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4763 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4764 UseAdaptiveSizePolicy = false; 4765 UseAdaptiveNUMAChunkSizing = false; 4766 } 4767 } 4768 } 4769 if (!UseNUMA && ForceNUMA) { 4770 UseNUMA = true; 4771 } 4772 } 4773 4774 if (MaxFDLimit) { 4775 // set the number of file descriptors to max. print out error 4776 // if getrlimit/setrlimit fails but continue regardless. 4777 struct rlimit nbr_files; 4778 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4779 if (status != 0) { 4780 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4781 perror("os::init_2 getrlimit failed"); 4782 } 4783 } else { 4784 nbr_files.rlim_cur = nbr_files.rlim_max; 4785 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4786 if (status != 0) { 4787 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4788 perror("os::init_2 setrlimit failed"); 4789 } 4790 } 4791 } 4792 } 4793 4794 // Initialize lock used to serialize thread creation (see os::create_thread) 4795 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4796 4797 // at-exit methods are called in the reverse order of their registration. 4798 // atexit functions are called on return from main or as a result of a 4799 // call to exit(3C). There can be only 32 of these functions registered 4800 // and atexit() does not set errno. 4801 4802 if (PerfAllowAtExitRegistration) { 4803 // only register atexit functions if PerfAllowAtExitRegistration is set. 4804 // atexit functions can be delayed until process exit time, which 4805 // can be problematic for embedded VM situations. Embedded VMs should 4806 // call DestroyJavaVM() to assure that VM resources are released. 4807 4808 // note: perfMemory_exit_helper atexit function may be removed in 4809 // the future if the appropriate cleanup code can be added to the 4810 // VM_Exit VMOperation's doit method. 4811 if (atexit(perfMemory_exit_helper) != 0) { 4812 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4813 } 4814 } 4815 4816 // initialize thread priority policy 4817 prio_init(); 4818 4819 return JNI_OK; 4820 } 4821 4822 // Mark the polling page as unreadable 4823 void os::make_polling_page_unreadable(void) { 4824 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4825 fatal("Could not disable polling page"); 4826 } 4827 } 4828 4829 // Mark the polling page as readable 4830 void os::make_polling_page_readable(void) { 4831 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4832 fatal("Could not enable polling page"); 4833 } 4834 } 4835 4836 int os::active_processor_count() { 4837 // Linux doesn't yet have a (official) notion of processor sets, 4838 // so just return the number of online processors. 4839 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4840 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4841 return online_cpus; 4842 } 4843 4844 void os::set_native_thread_name(const char *name) { 4845 if (Linux::_pthread_setname_np) { 4846 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4847 snprintf(buf, sizeof(buf), "%s", name); 4848 buf[sizeof(buf) - 1] = '\0'; 4849 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4850 // ERANGE should not happen; all other errors should just be ignored. 4851 assert(rc != ERANGE, "pthread_setname_np failed"); 4852 } 4853 } 4854 4855 bool os::distribute_processes(uint length, uint* distribution) { 4856 // Not yet implemented. 4857 return false; 4858 } 4859 4860 bool os::bind_to_processor(uint processor_id) { 4861 // Not yet implemented. 4862 return false; 4863 } 4864 4865 /// 4866 4867 void os::SuspendedThreadTask::internal_do_task() { 4868 if (do_suspend(_thread->osthread())) { 4869 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4870 do_task(context); 4871 do_resume(_thread->osthread()); 4872 } 4873 } 4874 4875 class PcFetcher : public os::SuspendedThreadTask { 4876 public: 4877 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4878 ExtendedPC result(); 4879 protected: 4880 void do_task(const os::SuspendedThreadTaskContext& context); 4881 private: 4882 ExtendedPC _epc; 4883 }; 4884 4885 ExtendedPC PcFetcher::result() { 4886 guarantee(is_done(), "task is not done yet."); 4887 return _epc; 4888 } 4889 4890 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4891 Thread* thread = context.thread(); 4892 OSThread* osthread = thread->osthread(); 4893 if (osthread->ucontext() != NULL) { 4894 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext()); 4895 } else { 4896 // NULL context is unexpected, double-check this is the VMThread 4897 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4898 } 4899 } 4900 4901 // Suspends the target using the signal mechanism and then grabs the PC before 4902 // resuming the target. Used by the flat-profiler only 4903 ExtendedPC os::get_thread_pc(Thread* thread) { 4904 // Make sure that it is called by the watcher for the VMThread 4905 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4906 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4907 4908 PcFetcher fetcher(thread); 4909 fetcher.run(); 4910 return fetcher.result(); 4911 } 4912 4913 //////////////////////////////////////////////////////////////////////////////// 4914 // debug support 4915 4916 bool os::find(address addr, outputStream* st) { 4917 Dl_info dlinfo; 4918 memset(&dlinfo, 0, sizeof(dlinfo)); 4919 if (dladdr(addr, &dlinfo) != 0) { 4920 st->print(PTR_FORMAT ": ", p2i(addr)); 4921 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 4922 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 4923 p2i(addr) - p2i(dlinfo.dli_saddr)); 4924 } else if (dlinfo.dli_fbase != NULL) { 4925 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 4926 } else { 4927 st->print("<absolute address>"); 4928 } 4929 if (dlinfo.dli_fname != NULL) { 4930 st->print(" in %s", dlinfo.dli_fname); 4931 } 4932 if (dlinfo.dli_fbase != NULL) { 4933 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 4934 } 4935 st->cr(); 4936 4937 if (Verbose) { 4938 // decode some bytes around the PC 4939 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4940 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4941 address lowest = (address) dlinfo.dli_sname; 4942 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4943 if (begin < lowest) begin = lowest; 4944 Dl_info dlinfo2; 4945 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 4946 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 4947 end = (address) dlinfo2.dli_saddr; 4948 } 4949 Disassembler::decode(begin, end, st); 4950 } 4951 return true; 4952 } 4953 return false; 4954 } 4955 4956 //////////////////////////////////////////////////////////////////////////////// 4957 // misc 4958 4959 // This does not do anything on Linux. This is basically a hook for being 4960 // able to use structured exception handling (thread-local exception filters) 4961 // on, e.g., Win32. 4962 void 4963 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4964 JavaCallArguments* args, Thread* thread) { 4965 f(value, method, args, thread); 4966 } 4967 4968 void os::print_statistics() { 4969 } 4970 4971 int os::message_box(const char* title, const char* message) { 4972 int i; 4973 fdStream err(defaultStream::error_fd()); 4974 for (i = 0; i < 78; i++) err.print_raw("="); 4975 err.cr(); 4976 err.print_raw_cr(title); 4977 for (i = 0; i < 78; i++) err.print_raw("-"); 4978 err.cr(); 4979 err.print_raw_cr(message); 4980 for (i = 0; i < 78; i++) err.print_raw("="); 4981 err.cr(); 4982 4983 char buf[16]; 4984 // Prevent process from exiting upon "read error" without consuming all CPU 4985 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4986 4987 return buf[0] == 'y' || buf[0] == 'Y'; 4988 } 4989 4990 int os::stat(const char *path, struct stat *sbuf) { 4991 char pathbuf[MAX_PATH]; 4992 if (strlen(path) > MAX_PATH - 1) { 4993 errno = ENAMETOOLONG; 4994 return -1; 4995 } 4996 os::native_path(strcpy(pathbuf, path)); 4997 return ::stat(pathbuf, sbuf); 4998 } 4999 5000 bool os::check_heap(bool force) { 5001 return true; 5002 } 5003 5004 // Is a (classpath) directory empty? 5005 bool os::dir_is_empty(const char* path) { 5006 DIR *dir = NULL; 5007 struct dirent *ptr; 5008 5009 dir = opendir(path); 5010 if (dir == NULL) return true; 5011 5012 // Scan the directory 5013 bool result = true; 5014 char buf[sizeof(struct dirent) + MAX_PATH]; 5015 while (result && (ptr = ::readdir(dir)) != NULL) { 5016 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5017 result = false; 5018 } 5019 } 5020 closedir(dir); 5021 return result; 5022 } 5023 5024 // This code originates from JDK's sysOpen and open64_w 5025 // from src/solaris/hpi/src/system_md.c 5026 5027 int os::open(const char *path, int oflag, int mode) { 5028 if (strlen(path) > MAX_PATH - 1) { 5029 errno = ENAMETOOLONG; 5030 return -1; 5031 } 5032 5033 // All file descriptors that are opened in the Java process and not 5034 // specifically destined for a subprocess should have the close-on-exec 5035 // flag set. If we don't set it, then careless 3rd party native code 5036 // might fork and exec without closing all appropriate file descriptors 5037 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5038 // turn might: 5039 // 5040 // - cause end-of-file to fail to be detected on some file 5041 // descriptors, resulting in mysterious hangs, or 5042 // 5043 // - might cause an fopen in the subprocess to fail on a system 5044 // suffering from bug 1085341. 5045 // 5046 // (Yes, the default setting of the close-on-exec flag is a Unix 5047 // design flaw) 5048 // 5049 // See: 5050 // 1085341: 32-bit stdio routines should support file descriptors >255 5051 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5052 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5053 // 5054 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5055 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5056 // because it saves a system call and removes a small window where the flag 5057 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5058 // and we fall back to using FD_CLOEXEC (see below). 5059 #ifdef O_CLOEXEC 5060 oflag |= O_CLOEXEC; 5061 #endif 5062 5063 int fd = ::open64(path, oflag, mode); 5064 if (fd == -1) return -1; 5065 5066 //If the open succeeded, the file might still be a directory 5067 { 5068 struct stat64 buf64; 5069 int ret = ::fstat64(fd, &buf64); 5070 int st_mode = buf64.st_mode; 5071 5072 if (ret != -1) { 5073 if ((st_mode & S_IFMT) == S_IFDIR) { 5074 errno = EISDIR; 5075 ::close(fd); 5076 return -1; 5077 } 5078 } else { 5079 ::close(fd); 5080 return -1; 5081 } 5082 } 5083 5084 #ifdef FD_CLOEXEC 5085 // Validate that the use of the O_CLOEXEC flag on open above worked. 5086 // With recent kernels, we will perform this check exactly once. 5087 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5088 if (!O_CLOEXEC_is_known_to_work) { 5089 int flags = ::fcntl(fd, F_GETFD); 5090 if (flags != -1) { 5091 if ((flags & FD_CLOEXEC) != 0) 5092 O_CLOEXEC_is_known_to_work = 1; 5093 else 5094 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5095 } 5096 } 5097 #endif 5098 5099 return fd; 5100 } 5101 5102 5103 // create binary file, rewriting existing file if required 5104 int os::create_binary_file(const char* path, bool rewrite_existing) { 5105 int oflags = O_WRONLY | O_CREAT; 5106 if (!rewrite_existing) { 5107 oflags |= O_EXCL; 5108 } 5109 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5110 } 5111 5112 // return current position of file pointer 5113 jlong os::current_file_offset(int fd) { 5114 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5115 } 5116 5117 // move file pointer to the specified offset 5118 jlong os::seek_to_file_offset(int fd, jlong offset) { 5119 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5120 } 5121 5122 // This code originates from JDK's sysAvailable 5123 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5124 5125 int os::available(int fd, jlong *bytes) { 5126 jlong cur, end; 5127 int mode; 5128 struct stat64 buf64; 5129 5130 if (::fstat64(fd, &buf64) >= 0) { 5131 mode = buf64.st_mode; 5132 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5133 // XXX: is the following call interruptible? If so, this might 5134 // need to go through the INTERRUPT_IO() wrapper as for other 5135 // blocking, interruptible calls in this file. 5136 int n; 5137 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5138 *bytes = n; 5139 return 1; 5140 } 5141 } 5142 } 5143 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5144 return 0; 5145 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5146 return 0; 5147 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5148 return 0; 5149 } 5150 *bytes = end - cur; 5151 return 1; 5152 } 5153 5154 // Map a block of memory. 5155 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5156 char *addr, size_t bytes, bool read_only, 5157 bool allow_exec) { 5158 int prot; 5159 int flags = MAP_PRIVATE; 5160 5161 if (read_only) { 5162 prot = PROT_READ; 5163 } else { 5164 prot = PROT_READ | PROT_WRITE; 5165 } 5166 5167 if (allow_exec) { 5168 prot |= PROT_EXEC; 5169 } 5170 5171 if (addr != NULL) { 5172 flags |= MAP_FIXED; 5173 } 5174 5175 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5176 fd, file_offset); 5177 if (mapped_address == MAP_FAILED) { 5178 return NULL; 5179 } 5180 return mapped_address; 5181 } 5182 5183 5184 // Remap a block of memory. 5185 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5186 char *addr, size_t bytes, bool read_only, 5187 bool allow_exec) { 5188 // same as map_memory() on this OS 5189 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5190 allow_exec); 5191 } 5192 5193 5194 // Unmap a block of memory. 5195 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5196 return munmap(addr, bytes) == 0; 5197 } 5198 5199 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5200 5201 static clockid_t thread_cpu_clockid(Thread* thread) { 5202 pthread_t tid = thread->osthread()->pthread_id(); 5203 clockid_t clockid; 5204 5205 // Get thread clockid 5206 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5207 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5208 return clockid; 5209 } 5210 5211 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5212 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5213 // of a thread. 5214 // 5215 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5216 // the fast estimate available on the platform. 5217 5218 jlong os::current_thread_cpu_time() { 5219 if (os::Linux::supports_fast_thread_cpu_time()) { 5220 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5221 } else { 5222 // return user + sys since the cost is the same 5223 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5224 } 5225 } 5226 5227 jlong os::thread_cpu_time(Thread* thread) { 5228 // consistent with what current_thread_cpu_time() returns 5229 if (os::Linux::supports_fast_thread_cpu_time()) { 5230 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5231 } else { 5232 return slow_thread_cpu_time(thread, true /* user + sys */); 5233 } 5234 } 5235 5236 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5237 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5238 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5239 } else { 5240 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5241 } 5242 } 5243 5244 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5245 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5246 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5247 } else { 5248 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5249 } 5250 } 5251 5252 // -1 on error. 5253 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5254 pid_t tid = thread->osthread()->thread_id(); 5255 char *s; 5256 char stat[2048]; 5257 int statlen; 5258 char proc_name[64]; 5259 int count; 5260 long sys_time, user_time; 5261 char cdummy; 5262 int idummy; 5263 long ldummy; 5264 FILE *fp; 5265 5266 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5267 fp = fopen(proc_name, "r"); 5268 if (fp == NULL) return -1; 5269 statlen = fread(stat, 1, 2047, fp); 5270 stat[statlen] = '\0'; 5271 fclose(fp); 5272 5273 // Skip pid and the command string. Note that we could be dealing with 5274 // weird command names, e.g. user could decide to rename java launcher 5275 // to "java 1.4.2 :)", then the stat file would look like 5276 // 1234 (java 1.4.2 :)) R ... ... 5277 // We don't really need to know the command string, just find the last 5278 // occurrence of ")" and then start parsing from there. See bug 4726580. 5279 s = strrchr(stat, ')'); 5280 if (s == NULL) return -1; 5281 5282 // Skip blank chars 5283 do { s++; } while (s && isspace(*s)); 5284 5285 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5286 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5287 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5288 &user_time, &sys_time); 5289 if (count != 13) return -1; 5290 if (user_sys_cpu_time) { 5291 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5292 } else { 5293 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5294 } 5295 } 5296 5297 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5298 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5299 info_ptr->may_skip_backward = false; // elapsed time not wall time 5300 info_ptr->may_skip_forward = false; // elapsed time not wall time 5301 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5302 } 5303 5304 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5305 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5306 info_ptr->may_skip_backward = false; // elapsed time not wall time 5307 info_ptr->may_skip_forward = false; // elapsed time not wall time 5308 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5309 } 5310 5311 bool os::is_thread_cpu_time_supported() { 5312 return true; 5313 } 5314 5315 // System loadavg support. Returns -1 if load average cannot be obtained. 5316 // Linux doesn't yet have a (official) notion of processor sets, 5317 // so just return the system wide load average. 5318 int os::loadavg(double loadavg[], int nelem) { 5319 return ::getloadavg(loadavg, nelem); 5320 } 5321 5322 void os::pause() { 5323 char filename[MAX_PATH]; 5324 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5325 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5326 } else { 5327 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5328 } 5329 5330 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5331 if (fd != -1) { 5332 struct stat buf; 5333 ::close(fd); 5334 while (::stat(filename, &buf) == 0) { 5335 (void)::poll(NULL, 0, 100); 5336 } 5337 } else { 5338 jio_fprintf(stderr, 5339 "Could not open pause file '%s', continuing immediately.\n", filename); 5340 } 5341 } 5342 5343 5344 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5345 // comment paragraphs are worth repeating here: 5346 // 5347 // Assumption: 5348 // Only one parker can exist on an event, which is why we allocate 5349 // them per-thread. Multiple unparkers can coexist. 5350 // 5351 // _Event serves as a restricted-range semaphore. 5352 // -1 : thread is blocked, i.e. there is a waiter 5353 // 0 : neutral: thread is running or ready, 5354 // could have been signaled after a wait started 5355 // 1 : signaled - thread is running or ready 5356 // 5357 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 5358 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 5359 // For specifics regarding the bug see GLIBC BUGID 261237 : 5360 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 5361 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 5362 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 5363 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 5364 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 5365 // and monitorenter when we're using 1-0 locking. All those operations may result in 5366 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 5367 // of libpthread avoids the problem, but isn't practical. 5368 // 5369 // Possible remedies: 5370 // 5371 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 5372 // This is palliative and probabilistic, however. If the thread is preempted 5373 // between the call to compute_abstime() and pthread_cond_timedwait(), more 5374 // than the minimum period may have passed, and the abstime may be stale (in the 5375 // past) resultin in a hang. Using this technique reduces the odds of a hang 5376 // but the JVM is still vulnerable, particularly on heavily loaded systems. 5377 // 5378 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5379 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5380 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5381 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5382 // thread. 5383 // 5384 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5385 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5386 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5387 // This also works well. In fact it avoids kernel-level scalability impediments 5388 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 5389 // timers in a graceful fashion. 5390 // 5391 // 4. When the abstime value is in the past it appears that control returns 5392 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5393 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5394 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 5395 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5396 // It may be possible to avoid reinitialization by checking the return 5397 // value from pthread_cond_timedwait(). In addition to reinitializing the 5398 // condvar we must establish the invariant that cond_signal() is only called 5399 // within critical sections protected by the adjunct mutex. This prevents 5400 // cond_signal() from "seeing" a condvar that's in the midst of being 5401 // reinitialized or that is corrupt. Sadly, this invariant obviates the 5402 // desirable signal-after-unlock optimization that avoids futile context switching. 5403 // 5404 // I'm also concerned that some versions of NTPL might allocate an auxilliary 5405 // structure when a condvar is used or initialized. cond_destroy() would 5406 // release the helper structure. Our reinitialize-after-timedwait fix 5407 // put excessive stress on malloc/free and locks protecting the c-heap. 5408 // 5409 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5410 // It may be possible to refine (4) by checking the kernel and NTPL verisons 5411 // and only enabling the work-around for vulnerable environments. 5412 5413 // utility to compute the abstime argument to timedwait: 5414 // millis is the relative timeout time 5415 // abstime will be the absolute timeout time 5416 // TODO: replace compute_abstime() with unpackTime() 5417 5418 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5419 if (millis < 0) millis = 0; 5420 5421 jlong seconds = millis / 1000; 5422 millis %= 1000; 5423 if (seconds > 50000000) { // see man cond_timedwait(3T) 5424 seconds = 50000000; 5425 } 5426 5427 if (os::supports_monotonic_clock()) { 5428 struct timespec now; 5429 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5430 assert_status(status == 0, status, "clock_gettime"); 5431 abstime->tv_sec = now.tv_sec + seconds; 5432 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5433 if (nanos >= NANOSECS_PER_SEC) { 5434 abstime->tv_sec += 1; 5435 nanos -= NANOSECS_PER_SEC; 5436 } 5437 abstime->tv_nsec = nanos; 5438 } else { 5439 struct timeval now; 5440 int status = gettimeofday(&now, NULL); 5441 assert(status == 0, "gettimeofday"); 5442 abstime->tv_sec = now.tv_sec + seconds; 5443 long usec = now.tv_usec + millis * 1000; 5444 if (usec >= 1000000) { 5445 abstime->tv_sec += 1; 5446 usec -= 1000000; 5447 } 5448 abstime->tv_nsec = usec * 1000; 5449 } 5450 return abstime; 5451 } 5452 5453 void os::PlatformEvent::park() { // AKA "down()" 5454 // Transitions for _Event: 5455 // -1 => -1 : illegal 5456 // 1 => 0 : pass - return immediately 5457 // 0 => -1 : block; then set _Event to 0 before returning 5458 5459 // Invariant: Only the thread associated with the Event/PlatformEvent 5460 // may call park(). 5461 // TODO: assert that _Assoc != NULL or _Assoc == Self 5462 assert(_nParked == 0, "invariant"); 5463 5464 int v; 5465 for (;;) { 5466 v = _Event; 5467 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5468 } 5469 guarantee(v >= 0, "invariant"); 5470 if (v == 0) { 5471 // Do this the hard way by blocking ... 5472 int status = pthread_mutex_lock(_mutex); 5473 assert_status(status == 0, status, "mutex_lock"); 5474 guarantee(_nParked == 0, "invariant"); 5475 ++_nParked; 5476 while (_Event < 0) { 5477 status = pthread_cond_wait(_cond, _mutex); 5478 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5479 // Treat this the same as if the wait was interrupted 5480 if (status == ETIME) { status = EINTR; } 5481 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5482 } 5483 --_nParked; 5484 5485 _Event = 0; 5486 status = pthread_mutex_unlock(_mutex); 5487 assert_status(status == 0, status, "mutex_unlock"); 5488 // Paranoia to ensure our locked and lock-free paths interact 5489 // correctly with each other. 5490 OrderAccess::fence(); 5491 } 5492 guarantee(_Event >= 0, "invariant"); 5493 } 5494 5495 int os::PlatformEvent::park(jlong millis) { 5496 // Transitions for _Event: 5497 // -1 => -1 : illegal 5498 // 1 => 0 : pass - return immediately 5499 // 0 => -1 : block; then set _Event to 0 before returning 5500 5501 guarantee(_nParked == 0, "invariant"); 5502 5503 int v; 5504 for (;;) { 5505 v = _Event; 5506 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5507 } 5508 guarantee(v >= 0, "invariant"); 5509 if (v != 0) return OS_OK; 5510 5511 // We do this the hard way, by blocking the thread. 5512 // Consider enforcing a minimum timeout value. 5513 struct timespec abst; 5514 compute_abstime(&abst, millis); 5515 5516 int ret = OS_TIMEOUT; 5517 int status = pthread_mutex_lock(_mutex); 5518 assert_status(status == 0, status, "mutex_lock"); 5519 guarantee(_nParked == 0, "invariant"); 5520 ++_nParked; 5521 5522 // Object.wait(timo) will return because of 5523 // (a) notification 5524 // (b) timeout 5525 // (c) thread.interrupt 5526 // 5527 // Thread.interrupt and object.notify{All} both call Event::set. 5528 // That is, we treat thread.interrupt as a special case of notification. 5529 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5530 // We assume all ETIME returns are valid. 5531 // 5532 // TODO: properly differentiate simultaneous notify+interrupt. 5533 // In that case, we should propagate the notify to another waiter. 5534 5535 while (_Event < 0) { 5536 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5537 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5538 pthread_cond_destroy(_cond); 5539 pthread_cond_init(_cond, os::Linux::condAttr()); 5540 } 5541 assert_status(status == 0 || status == EINTR || 5542 status == ETIME || status == ETIMEDOUT, 5543 status, "cond_timedwait"); 5544 if (!FilterSpuriousWakeups) break; // previous semantics 5545 if (status == ETIME || status == ETIMEDOUT) break; 5546 // We consume and ignore EINTR and spurious wakeups. 5547 } 5548 --_nParked; 5549 if (_Event >= 0) { 5550 ret = OS_OK; 5551 } 5552 _Event = 0; 5553 status = pthread_mutex_unlock(_mutex); 5554 assert_status(status == 0, status, "mutex_unlock"); 5555 assert(_nParked == 0, "invariant"); 5556 // Paranoia to ensure our locked and lock-free paths interact 5557 // correctly with each other. 5558 OrderAccess::fence(); 5559 return ret; 5560 } 5561 5562 void os::PlatformEvent::unpark() { 5563 // Transitions for _Event: 5564 // 0 => 1 : just return 5565 // 1 => 1 : just return 5566 // -1 => either 0 or 1; must signal target thread 5567 // That is, we can safely transition _Event from -1 to either 5568 // 0 or 1. 5569 // See also: "Semaphores in Plan 9" by Mullender & Cox 5570 // 5571 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5572 // that it will take two back-to-back park() calls for the owning 5573 // thread to block. This has the benefit of forcing a spurious return 5574 // from the first park() call after an unpark() call which will help 5575 // shake out uses of park() and unpark() without condition variables. 5576 5577 if (Atomic::xchg(1, &_Event) >= 0) return; 5578 5579 // Wait for the thread associated with the event to vacate 5580 int status = pthread_mutex_lock(_mutex); 5581 assert_status(status == 0, status, "mutex_lock"); 5582 int AnyWaiters = _nParked; 5583 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5584 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5585 AnyWaiters = 0; 5586 pthread_cond_signal(_cond); 5587 } 5588 status = pthread_mutex_unlock(_mutex); 5589 assert_status(status == 0, status, "mutex_unlock"); 5590 if (AnyWaiters != 0) { 5591 // Note that we signal() *after* dropping the lock for "immortal" Events. 5592 // This is safe and avoids a common class of futile wakeups. In rare 5593 // circumstances this can cause a thread to return prematurely from 5594 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5595 // will simply re-test the condition and re-park itself. 5596 // This provides particular benefit if the underlying platform does not 5597 // provide wait morphing. 5598 status = pthread_cond_signal(_cond); 5599 assert_status(status == 0, status, "cond_signal"); 5600 } 5601 } 5602 5603 5604 // JSR166 5605 // ------------------------------------------------------- 5606 5607 // The solaris and linux implementations of park/unpark are fairly 5608 // conservative for now, but can be improved. They currently use a 5609 // mutex/condvar pair, plus a a count. 5610 // Park decrements count if > 0, else does a condvar wait. Unpark 5611 // sets count to 1 and signals condvar. Only one thread ever waits 5612 // on the condvar. Contention seen when trying to park implies that someone 5613 // is unparking you, so don't wait. And spurious returns are fine, so there 5614 // is no need to track notifications. 5615 5616 // This code is common to linux and solaris and will be moved to a 5617 // common place in dolphin. 5618 // 5619 // The passed in time value is either a relative time in nanoseconds 5620 // or an absolute time in milliseconds. Either way it has to be unpacked 5621 // into suitable seconds and nanoseconds components and stored in the 5622 // given timespec structure. 5623 // Given time is a 64-bit value and the time_t used in the timespec is only 5624 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5625 // overflow if times way in the future are given. Further on Solaris versions 5626 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5627 // number of seconds, in abstime, is less than current_time + 100,000,000. 5628 // As it will be 28 years before "now + 100000000" will overflow we can 5629 // ignore overflow and just impose a hard-limit on seconds using the value 5630 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5631 // years from "now". 5632 5633 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5634 assert(time > 0, "convertTime"); 5635 time_t max_secs = 0; 5636 5637 if (!os::supports_monotonic_clock() || isAbsolute) { 5638 struct timeval now; 5639 int status = gettimeofday(&now, NULL); 5640 assert(status == 0, "gettimeofday"); 5641 5642 max_secs = now.tv_sec + MAX_SECS; 5643 5644 if (isAbsolute) { 5645 jlong secs = time / 1000; 5646 if (secs > max_secs) { 5647 absTime->tv_sec = max_secs; 5648 } else { 5649 absTime->tv_sec = secs; 5650 } 5651 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5652 } else { 5653 jlong secs = time / NANOSECS_PER_SEC; 5654 if (secs >= MAX_SECS) { 5655 absTime->tv_sec = max_secs; 5656 absTime->tv_nsec = 0; 5657 } else { 5658 absTime->tv_sec = now.tv_sec + secs; 5659 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5660 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5661 absTime->tv_nsec -= NANOSECS_PER_SEC; 5662 ++absTime->tv_sec; // note: this must be <= max_secs 5663 } 5664 } 5665 } 5666 } else { 5667 // must be relative using monotonic clock 5668 struct timespec now; 5669 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5670 assert_status(status == 0, status, "clock_gettime"); 5671 max_secs = now.tv_sec + MAX_SECS; 5672 jlong secs = time / NANOSECS_PER_SEC; 5673 if (secs >= MAX_SECS) { 5674 absTime->tv_sec = max_secs; 5675 absTime->tv_nsec = 0; 5676 } else { 5677 absTime->tv_sec = now.tv_sec + secs; 5678 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5679 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5680 absTime->tv_nsec -= NANOSECS_PER_SEC; 5681 ++absTime->tv_sec; // note: this must be <= max_secs 5682 } 5683 } 5684 } 5685 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5686 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5687 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5688 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5689 } 5690 5691 void Parker::park(bool isAbsolute, jlong time) { 5692 // Ideally we'd do something useful while spinning, such 5693 // as calling unpackTime(). 5694 5695 // Optional fast-path check: 5696 // Return immediately if a permit is available. 5697 // We depend on Atomic::xchg() having full barrier semantics 5698 // since we are doing a lock-free update to _counter. 5699 if (Atomic::xchg(0, &_counter) > 0) return; 5700 5701 Thread* thread = Thread::current(); 5702 assert(thread->is_Java_thread(), "Must be JavaThread"); 5703 JavaThread *jt = (JavaThread *)thread; 5704 5705 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5706 // Check interrupt before trying to wait 5707 if (Thread::is_interrupted(thread, false)) { 5708 return; 5709 } 5710 5711 // Next, demultiplex/decode time arguments 5712 timespec absTime; 5713 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5714 return; 5715 } 5716 if (time > 0) { 5717 unpackTime(&absTime, isAbsolute, time); 5718 } 5719 5720 5721 // Enter safepoint region 5722 // Beware of deadlocks such as 6317397. 5723 // The per-thread Parker:: mutex is a classic leaf-lock. 5724 // In particular a thread must never block on the Threads_lock while 5725 // holding the Parker:: mutex. If safepoints are pending both the 5726 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5727 ThreadBlockInVM tbivm(jt); 5728 5729 // Don't wait if cannot get lock since interference arises from 5730 // unblocking. Also. check interrupt before trying wait 5731 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5732 return; 5733 } 5734 5735 int status; 5736 if (_counter > 0) { // no wait needed 5737 _counter = 0; 5738 status = pthread_mutex_unlock(_mutex); 5739 assert(status == 0, "invariant"); 5740 // Paranoia to ensure our locked and lock-free paths interact 5741 // correctly with each other and Java-level accesses. 5742 OrderAccess::fence(); 5743 return; 5744 } 5745 5746 #ifdef ASSERT 5747 // Don't catch signals while blocked; let the running threads have the signals. 5748 // (This allows a debugger to break into the running thread.) 5749 sigset_t oldsigs; 5750 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5751 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5752 #endif 5753 5754 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5755 jt->set_suspend_equivalent(); 5756 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5757 5758 assert(_cur_index == -1, "invariant"); 5759 if (time == 0) { 5760 _cur_index = REL_INDEX; // arbitrary choice when not timed 5761 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5762 } else { 5763 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5764 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5765 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5766 pthread_cond_destroy(&_cond[_cur_index]); 5767 pthread_cond_init(&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr()); 5768 } 5769 } 5770 _cur_index = -1; 5771 assert_status(status == 0 || status == EINTR || 5772 status == ETIME || status == ETIMEDOUT, 5773 status, "cond_timedwait"); 5774 5775 #ifdef ASSERT 5776 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5777 #endif 5778 5779 _counter = 0; 5780 status = pthread_mutex_unlock(_mutex); 5781 assert_status(status == 0, status, "invariant"); 5782 // Paranoia to ensure our locked and lock-free paths interact 5783 // correctly with each other and Java-level accesses. 5784 OrderAccess::fence(); 5785 5786 // If externally suspended while waiting, re-suspend 5787 if (jt->handle_special_suspend_equivalent_condition()) { 5788 jt->java_suspend_self(); 5789 } 5790 } 5791 5792 void Parker::unpark() { 5793 int status = pthread_mutex_lock(_mutex); 5794 assert(status == 0, "invariant"); 5795 const int s = _counter; 5796 _counter = 1; 5797 if (s < 1) { 5798 // thread might be parked 5799 if (_cur_index != -1) { 5800 // thread is definitely parked 5801 if (WorkAroundNPTLTimedWaitHang) { 5802 status = pthread_cond_signal(&_cond[_cur_index]); 5803 assert(status == 0, "invariant"); 5804 status = pthread_mutex_unlock(_mutex); 5805 assert(status == 0, "invariant"); 5806 } else { 5807 // must capture correct index before unlocking 5808 int index = _cur_index; 5809 status = pthread_mutex_unlock(_mutex); 5810 assert(status == 0, "invariant"); 5811 status = pthread_cond_signal(&_cond[index]); 5812 assert(status == 0, "invariant"); 5813 } 5814 } else { 5815 pthread_mutex_unlock(_mutex); 5816 assert(status == 0, "invariant"); 5817 } 5818 } else { 5819 pthread_mutex_unlock(_mutex); 5820 assert(status == 0, "invariant"); 5821 } 5822 } 5823 5824 5825 extern char** environ; 5826 5827 // Run the specified command in a separate process. Return its exit value, 5828 // or -1 on failure (e.g. can't fork a new process). 5829 // Unlike system(), this function can be called from signal handler. It 5830 // doesn't block SIGINT et al. 5831 int os::fork_and_exec(char* cmd) { 5832 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5833 5834 pid_t pid = fork(); 5835 5836 if (pid < 0) { 5837 // fork failed 5838 return -1; 5839 5840 } else if (pid == 0) { 5841 // child process 5842 5843 execve("/bin/sh", (char* const*)argv, environ); 5844 5845 // execve failed 5846 _exit(-1); 5847 5848 } else { 5849 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5850 // care about the actual exit code, for now. 5851 5852 int status; 5853 5854 // Wait for the child process to exit. This returns immediately if 5855 // the child has already exited. */ 5856 while (waitpid(pid, &status, 0) < 0) { 5857 switch (errno) { 5858 case ECHILD: return 0; 5859 case EINTR: break; 5860 default: return -1; 5861 } 5862 } 5863 5864 if (WIFEXITED(status)) { 5865 // The child exited normally; get its exit code. 5866 return WEXITSTATUS(status); 5867 } else if (WIFSIGNALED(status)) { 5868 // The child exited because of a signal 5869 // The best value to return is 0x80 + signal number, 5870 // because that is what all Unix shells do, and because 5871 // it allows callers to distinguish between process exit and 5872 // process death by signal. 5873 return 0x80 + WTERMSIG(status); 5874 } else { 5875 // Unknown exit code; pass it through 5876 return status; 5877 } 5878 } 5879 } 5880 5881 // is_headless_jre() 5882 // 5883 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5884 // in order to report if we are running in a headless jre 5885 // 5886 // Since JDK8 xawt/libmawt.so was moved into the same directory 5887 // as libawt.so, and renamed libawt_xawt.so 5888 // 5889 bool os::is_headless_jre() { 5890 struct stat statbuf; 5891 char buf[MAXPATHLEN]; 5892 char libmawtpath[MAXPATHLEN]; 5893 const char *xawtstr = "/xawt/libmawt.so"; 5894 const char *new_xawtstr = "/libawt_xawt.so"; 5895 char *p; 5896 5897 // Get path to libjvm.so 5898 os::jvm_path(buf, sizeof(buf)); 5899 5900 // Get rid of libjvm.so 5901 p = strrchr(buf, '/'); 5902 if (p == NULL) { 5903 return false; 5904 } else { 5905 *p = '\0'; 5906 } 5907 5908 // Get rid of client or server 5909 p = strrchr(buf, '/'); 5910 if (p == NULL) { 5911 return false; 5912 } else { 5913 *p = '\0'; 5914 } 5915 5916 // check xawt/libmawt.so 5917 strcpy(libmawtpath, buf); 5918 strcat(libmawtpath, xawtstr); 5919 if (::stat(libmawtpath, &statbuf) == 0) return false; 5920 5921 // check libawt_xawt.so 5922 strcpy(libmawtpath, buf); 5923 strcat(libmawtpath, new_xawtstr); 5924 if (::stat(libmawtpath, &statbuf) == 0) return false; 5925 5926 return true; 5927 } 5928 5929 // Get the default path to the core file 5930 // Returns the length of the string 5931 int os::get_core_path(char* buffer, size_t bufferSize) { 5932 /* 5933 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5934 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5935 */ 5936 const int core_pattern_len = 129; 5937 char core_pattern[core_pattern_len] = {0}; 5938 5939 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5940 if (core_pattern_file != -1) { 5941 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5942 ::close(core_pattern_file); 5943 5944 if (ret > 0) { 5945 char *last_char = core_pattern + strlen(core_pattern) - 1; 5946 5947 if (*last_char == '\n') { 5948 *last_char = '\0'; 5949 } 5950 } 5951 } 5952 5953 if (strlen(core_pattern) == 0) { 5954 return -1; 5955 } 5956 5957 char *pid_pos = strstr(core_pattern, "%p"); 5958 int written; 5959 5960 if (core_pattern[0] == '/') { 5961 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5962 } else { 5963 char cwd[PATH_MAX]; 5964 5965 const char* p = get_current_directory(cwd, PATH_MAX); 5966 if (p == NULL) { 5967 return -1; 5968 } 5969 5970 if (core_pattern[0] == '|') { 5971 written = jio_snprintf(buffer, bufferSize, 5972 "\"%s\" (or dumping to %s/core.%d)", 5973 &core_pattern[1], p, current_process_id()); 5974 } else { 5975 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5976 } 5977 } 5978 5979 if (written < 0) { 5980 return -1; 5981 } 5982 5983 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5984 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5985 5986 if (core_uses_pid_file != -1) { 5987 char core_uses_pid = 0; 5988 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5989 ::close(core_uses_pid_file); 5990 5991 if (core_uses_pid == '1') { 5992 jio_snprintf(buffer + written, bufferSize - written, 5993 ".%d", current_process_id()); 5994 } 5995 } 5996 } 5997 5998 return strlen(buffer); 5999 } 6000 6001 /////////////// Unit tests /////////////// 6002 6003 #ifndef PRODUCT 6004 6005 #define test_log(...) \ 6006 do { \ 6007 if (VerboseInternalVMTests) { \ 6008 tty->print_cr(__VA_ARGS__); \ 6009 tty->flush(); \ 6010 } \ 6011 } while (false) 6012 6013 class TestReserveMemorySpecial : AllStatic { 6014 public: 6015 static void small_page_write(void* addr, size_t size) { 6016 size_t page_size = os::vm_page_size(); 6017 6018 char* end = (char*)addr + size; 6019 for (char* p = (char*)addr; p < end; p += page_size) { 6020 *p = 1; 6021 } 6022 } 6023 6024 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6025 if (!UseHugeTLBFS) { 6026 return; 6027 } 6028 6029 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6030 6031 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6032 6033 if (addr != NULL) { 6034 small_page_write(addr, size); 6035 6036 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6037 } 6038 } 6039 6040 static void test_reserve_memory_special_huge_tlbfs_only() { 6041 if (!UseHugeTLBFS) { 6042 return; 6043 } 6044 6045 size_t lp = os::large_page_size(); 6046 6047 for (size_t size = lp; size <= lp * 10; size += lp) { 6048 test_reserve_memory_special_huge_tlbfs_only(size); 6049 } 6050 } 6051 6052 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6053 size_t lp = os::large_page_size(); 6054 size_t ag = os::vm_allocation_granularity(); 6055 6056 // sizes to test 6057 const size_t sizes[] = { 6058 lp, lp + ag, lp + lp / 2, lp * 2, 6059 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6060 lp * 10, lp * 10 + lp / 2 6061 }; 6062 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6063 6064 // For each size/alignment combination, we test three scenarios: 6065 // 1) with req_addr == NULL 6066 // 2) with a non-null req_addr at which we expect to successfully allocate 6067 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6068 // expect the allocation to either fail or to ignore req_addr 6069 6070 // Pre-allocate two areas; they shall be as large as the largest allocation 6071 // and aligned to the largest alignment we will be testing. 6072 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6073 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6074 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6075 -1, 0); 6076 assert(mapping1 != MAP_FAILED, "should work"); 6077 6078 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6079 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6080 -1, 0); 6081 assert(mapping2 != MAP_FAILED, "should work"); 6082 6083 // Unmap the first mapping, but leave the second mapping intact: the first 6084 // mapping will serve as a value for a "good" req_addr (case 2). The second 6085 // mapping, still intact, as "bad" req_addr (case 3). 6086 ::munmap(mapping1, mapping_size); 6087 6088 // Case 1 6089 test_log("%s, req_addr NULL:", __FUNCTION__); 6090 test_log("size align result"); 6091 6092 for (int i = 0; i < num_sizes; i++) { 6093 const size_t size = sizes[i]; 6094 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6095 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6096 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6097 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6098 if (p != NULL) { 6099 assert(is_ptr_aligned(p, alignment), "must be"); 6100 small_page_write(p, size); 6101 os::Linux::release_memory_special_huge_tlbfs(p, size); 6102 } 6103 } 6104 } 6105 6106 // Case 2 6107 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6108 test_log("size align req_addr result"); 6109 6110 for (int i = 0; i < num_sizes; i++) { 6111 const size_t size = sizes[i]; 6112 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6113 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6114 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6115 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6116 size, alignment, p2i(req_addr), p2i(p), 6117 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6118 if (p != NULL) { 6119 assert(p == req_addr, "must be"); 6120 small_page_write(p, size); 6121 os::Linux::release_memory_special_huge_tlbfs(p, size); 6122 } 6123 } 6124 } 6125 6126 // Case 3 6127 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6128 test_log("size align req_addr result"); 6129 6130 for (int i = 0; i < num_sizes; i++) { 6131 const size_t size = sizes[i]; 6132 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6133 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6134 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6135 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6136 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6137 // as the area around req_addr contains already existing mappings, the API should always 6138 // return NULL (as per contract, it cannot return another address) 6139 assert(p == NULL, "must be"); 6140 } 6141 } 6142 6143 ::munmap(mapping2, mapping_size); 6144 6145 } 6146 6147 static void test_reserve_memory_special_huge_tlbfs() { 6148 if (!UseHugeTLBFS) { 6149 return; 6150 } 6151 6152 test_reserve_memory_special_huge_tlbfs_only(); 6153 test_reserve_memory_special_huge_tlbfs_mixed(); 6154 } 6155 6156 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6157 if (!UseSHM) { 6158 return; 6159 } 6160 6161 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6162 6163 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6164 6165 if (addr != NULL) { 6166 assert(is_ptr_aligned(addr, alignment), "Check"); 6167 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6168 6169 small_page_write(addr, size); 6170 6171 os::Linux::release_memory_special_shm(addr, size); 6172 } 6173 } 6174 6175 static void test_reserve_memory_special_shm() { 6176 size_t lp = os::large_page_size(); 6177 size_t ag = os::vm_allocation_granularity(); 6178 6179 for (size_t size = ag; size < lp * 3; size += ag) { 6180 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6181 test_reserve_memory_special_shm(size, alignment); 6182 } 6183 } 6184 } 6185 6186 static void test() { 6187 test_reserve_memory_special_huge_tlbfs(); 6188 test_reserve_memory_special_shm(); 6189 } 6190 }; 6191 6192 void TestReserveMemorySpecial_test() { 6193 TestReserveMemorySpecial::test(); 6194 } 6195 6196 #endif