1 /* 2 * Copyright (c) 1999, 2018, 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 "jvm.h" 27 #include "classfile/classLoader.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/icBuffer.hpp" 31 #include "code/vtableStubs.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "compiler/disassembler.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "logging/log.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_linux.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "osContainer_linux.hpp" 42 #include "prims/jniFastGetField.hpp" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/atomic.hpp" 46 #include "runtime/extendedPC.hpp" 47 #include "runtime/globals.hpp" 48 #include "runtime/interfaceSupport.inline.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/threadSMR.hpp" 63 #include "runtime/timer.hpp" 64 #include "semaphore_posix.hpp" 65 #include "services/attachListener.hpp" 66 #include "services/memTracker.hpp" 67 #include "services/runtimeService.hpp" 68 #include "utilities/align.hpp" 69 #include "utilities/decoder.hpp" 70 #include "utilities/defaultStream.hpp" 71 #include "utilities/events.hpp" 72 #include "utilities/elfFile.hpp" 73 #include "utilities/growableArray.hpp" 74 #include "utilities/macros.hpp" 75 #include "utilities/vmError.hpp" 76 77 // put OS-includes here 78 # include <sys/types.h> 79 # include <sys/mman.h> 80 # include <sys/stat.h> 81 # include <sys/select.h> 82 # include <pthread.h> 83 # include <signal.h> 84 # include <errno.h> 85 # include <dlfcn.h> 86 # include <stdio.h> 87 # include <unistd.h> 88 # include <sys/resource.h> 89 # include <pthread.h> 90 # include <sys/stat.h> 91 # include <sys/time.h> 92 # include <sys/times.h> 93 # include <sys/utsname.h> 94 # include <sys/socket.h> 95 # include <sys/wait.h> 96 # include <pwd.h> 97 # include <poll.h> 98 # include <fcntl.h> 99 # include <string.h> 100 # include <syscall.h> 101 # include <sys/sysinfo.h> 102 # include <gnu/libc-version.h> 103 # include <sys/ipc.h> 104 # include <sys/shm.h> 105 # include <link.h> 106 # include <stdint.h> 107 # include <inttypes.h> 108 # include <sys/ioctl.h> 109 110 #ifndef _GNU_SOURCE 111 #define _GNU_SOURCE 112 #include <sched.h> 113 #undef _GNU_SOURCE 114 #else 115 #include <sched.h> 116 #endif 117 118 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 119 // getrusage() is prepared to handle the associated failure. 120 #ifndef RUSAGE_THREAD 121 #define RUSAGE_THREAD (1) /* only the calling thread */ 122 #endif 123 124 #define MAX_PATH (2 * K) 125 126 #define MAX_SECS 100000000 127 128 // for timer info max values which include all bits 129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 130 131 #define LARGEPAGES_BIT (1 << 6) 132 #define DAX_SHARED_BIT (1 << 8) 133 //////////////////////////////////////////////////////////////////////////////// 134 // global variables 135 julong os::Linux::_physical_memory = 0; 136 137 address os::Linux::_initial_thread_stack_bottom = NULL; 138 uintptr_t os::Linux::_initial_thread_stack_size = 0; 139 140 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 141 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 142 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 143 Mutex* os::Linux::_createThread_lock = NULL; 144 pthread_t os::Linux::_main_thread; 145 int os::Linux::_page_size = -1; 146 bool os::Linux::_supports_fast_thread_cpu_time = false; 147 uint32_t os::Linux::_os_version = 0; 148 const char * os::Linux::_glibc_version = NULL; 149 const char * os::Linux::_libpthread_version = NULL; 150 151 static jlong initial_time_count=0; 152 153 static int clock_tics_per_sec = 100; 154 155 // If the VM might have been created on the primordial thread, we need to resolve the 156 // primordial thread stack bounds and check if the current thread might be the 157 // primordial thread in places. If we know that the primordial thread is never used, 158 // such as when the VM was created by one of the standard java launchers, we can 159 // avoid this 160 static bool suppress_primordial_thread_resolution = false; 161 162 // For diagnostics to print a message once. see run_periodic_checks 163 static sigset_t check_signal_done; 164 static bool check_signals = true; 165 166 // Signal number used to suspend/resume a thread 167 168 // do not use any signal number less than SIGSEGV, see 4355769 169 static int SR_signum = SIGUSR2; 170 sigset_t SR_sigset; 171 172 // utility functions 173 174 static int SR_initialize(); 175 176 julong os::available_memory() { 177 return Linux::available_memory(); 178 } 179 180 julong os::Linux::available_memory() { 181 // values in struct sysinfo are "unsigned long" 182 struct sysinfo si; 183 julong avail_mem; 184 185 if (OSContainer::is_containerized()) { 186 jlong mem_limit, mem_usage; 187 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 188 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 189 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 190 } 191 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 192 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 193 } 194 if (mem_limit > 0 && mem_usage > 0 ) { 195 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 196 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 197 return avail_mem; 198 } 199 } 200 201 sysinfo(&si); 202 avail_mem = (julong)si.freeram * si.mem_unit; 203 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 204 return avail_mem; 205 } 206 207 julong os::physical_memory() { 208 jlong phys_mem = 0; 209 if (OSContainer::is_containerized()) { 210 jlong mem_limit; 211 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 212 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 213 return mem_limit; 214 } 215 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 216 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 217 } 218 219 phys_mem = Linux::physical_memory(); 220 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 221 return phys_mem; 222 } 223 224 // Return true if user is running as root. 225 226 bool os::have_special_privileges() { 227 static bool init = false; 228 static bool privileges = false; 229 if (!init) { 230 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 231 init = true; 232 } 233 return privileges; 234 } 235 236 237 #ifndef SYS_gettid 238 // i386: 224, ia64: 1105, amd64: 186, sparc 143 239 #ifdef __ia64__ 240 #define SYS_gettid 1105 241 #else 242 #ifdef __i386__ 243 #define SYS_gettid 224 244 #else 245 #ifdef __amd64__ 246 #define SYS_gettid 186 247 #else 248 #ifdef __sparc__ 249 #define SYS_gettid 143 250 #else 251 #error define gettid for the arch 252 #endif 253 #endif 254 #endif 255 #endif 256 #endif 257 258 259 // pid_t gettid() 260 // 261 // Returns the kernel thread id of the currently running thread. Kernel 262 // thread id is used to access /proc. 263 pid_t os::Linux::gettid() { 264 int rslt = syscall(SYS_gettid); 265 assert(rslt != -1, "must be."); // old linuxthreads implementation? 266 return (pid_t)rslt; 267 } 268 269 // Most versions of linux have a bug where the number of processors are 270 // determined by looking at the /proc file system. In a chroot environment, 271 // the system call returns 1. This causes the VM to act as if it is 272 // a single processor and elide locking (see is_MP() call). 273 static bool unsafe_chroot_detected = false; 274 static const char *unstable_chroot_error = "/proc file system not found.\n" 275 "Java may be unstable running multithreaded in a chroot " 276 "environment on Linux when /proc filesystem is not mounted."; 277 278 void os::Linux::initialize_system_info() { 279 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 280 if (processor_count() == 1) { 281 pid_t pid = os::Linux::gettid(); 282 char fname[32]; 283 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 284 FILE *fp = fopen(fname, "r"); 285 if (fp == NULL) { 286 unsafe_chroot_detected = true; 287 } else { 288 fclose(fp); 289 } 290 } 291 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 292 assert(processor_count() > 0, "linux error"); 293 } 294 295 void os::init_system_properties_values() { 296 // The next steps are taken in the product version: 297 // 298 // Obtain the JAVA_HOME value from the location of libjvm.so. 299 // This library should be located at: 300 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 301 // 302 // If "/jre/lib/" appears at the right place in the path, then we 303 // assume libjvm.so is installed in a JDK and we use this path. 304 // 305 // Otherwise exit with message: "Could not create the Java virtual machine." 306 // 307 // The following extra steps are taken in the debugging version: 308 // 309 // If "/jre/lib/" does NOT appear at the right place in the path 310 // instead of exit check for $JAVA_HOME environment variable. 311 // 312 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 313 // then we append a fake suffix "hotspot/libjvm.so" to this path so 314 // it looks like libjvm.so is installed there 315 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 316 // 317 // Otherwise exit. 318 // 319 // Important note: if the location of libjvm.so changes this 320 // code needs to be changed accordingly. 321 322 // See ld(1): 323 // The linker uses the following search paths to locate required 324 // shared libraries: 325 // 1: ... 326 // ... 327 // 7: The default directories, normally /lib and /usr/lib. 328 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 329 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 330 #else 331 #define DEFAULT_LIBPATH "/lib:/usr/lib" 332 #endif 333 334 // Base path of extensions installed on the system. 335 #define SYS_EXT_DIR "/usr/java/packages" 336 #define EXTENSIONS_DIR "/lib/ext" 337 338 // Buffer that fits several sprintfs. 339 // Note that the space for the colon and the trailing null are provided 340 // by the nulls included by the sizeof operator. 341 const size_t bufsize = 342 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 343 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 344 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 345 346 // sysclasspath, java_home, dll_dir 347 { 348 char *pslash; 349 os::jvm_path(buf, bufsize); 350 351 // Found the full path to libjvm.so. 352 // Now cut the path to <java_home>/jre if we can. 353 pslash = strrchr(buf, '/'); 354 if (pslash != NULL) { 355 *pslash = '\0'; // Get rid of /libjvm.so. 356 } 357 pslash = strrchr(buf, '/'); 358 if (pslash != NULL) { 359 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 360 } 361 Arguments::set_dll_dir(buf); 362 363 if (pslash != NULL) { 364 pslash = strrchr(buf, '/'); 365 if (pslash != NULL) { 366 *pslash = '\0'; // Get rid of /lib. 367 } 368 } 369 Arguments::set_java_home(buf); 370 set_boot_path('/', ':'); 371 } 372 373 // Where to look for native libraries. 374 // 375 // Note: Due to a legacy implementation, most of the library path 376 // is set in the launcher. This was to accomodate linking restrictions 377 // on legacy Linux implementations (which are no longer supported). 378 // Eventually, all the library path setting will be done here. 379 // 380 // However, to prevent the proliferation of improperly built native 381 // libraries, the new path component /usr/java/packages is added here. 382 // Eventually, all the library path setting will be done here. 383 { 384 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 385 // should always exist (until the legacy problem cited above is 386 // addressed). 387 const char *v = ::getenv("LD_LIBRARY_PATH"); 388 const char *v_colon = ":"; 389 if (v == NULL) { v = ""; v_colon = ""; } 390 // That's +1 for the colon and +1 for the trailing '\0'. 391 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 392 strlen(v) + 1 + 393 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 394 mtInternal); 395 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 396 Arguments::set_library_path(ld_library_path); 397 FREE_C_HEAP_ARRAY(char, ld_library_path); 398 } 399 400 // Extensions directories. 401 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 402 Arguments::set_ext_dirs(buf); 403 404 FREE_C_HEAP_ARRAY(char, buf); 405 406 #undef DEFAULT_LIBPATH 407 #undef SYS_EXT_DIR 408 #undef EXTENSIONS_DIR 409 } 410 411 //////////////////////////////////////////////////////////////////////////////// 412 // breakpoint support 413 414 void os::breakpoint() { 415 BREAKPOINT; 416 } 417 418 extern "C" void breakpoint() { 419 // use debugger to set breakpoint here 420 } 421 422 //////////////////////////////////////////////////////////////////////////////// 423 // signal support 424 425 debug_only(static bool signal_sets_initialized = false); 426 static sigset_t unblocked_sigs, vm_sigs; 427 428 bool os::Linux::is_sig_ignored(int sig) { 429 struct sigaction oact; 430 sigaction(sig, (struct sigaction*)NULL, &oact); 431 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 432 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 433 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 434 return true; 435 } else { 436 return false; 437 } 438 } 439 440 void os::Linux::signal_sets_init() { 441 // Should also have an assertion stating we are still single-threaded. 442 assert(!signal_sets_initialized, "Already initialized"); 443 // Fill in signals that are necessarily unblocked for all threads in 444 // the VM. Currently, we unblock the following signals: 445 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 446 // by -Xrs (=ReduceSignalUsage)); 447 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 448 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 449 // the dispositions or masks wrt these signals. 450 // Programs embedding the VM that want to use the above signals for their 451 // own purposes must, at this time, use the "-Xrs" option to prevent 452 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 453 // (See bug 4345157, and other related bugs). 454 // In reality, though, unblocking these signals is really a nop, since 455 // these signals are not blocked by default. 456 sigemptyset(&unblocked_sigs); 457 sigaddset(&unblocked_sigs, SIGILL); 458 sigaddset(&unblocked_sigs, SIGSEGV); 459 sigaddset(&unblocked_sigs, SIGBUS); 460 sigaddset(&unblocked_sigs, SIGFPE); 461 #if defined(PPC64) 462 sigaddset(&unblocked_sigs, SIGTRAP); 463 #endif 464 sigaddset(&unblocked_sigs, SR_signum); 465 466 if (!ReduceSignalUsage) { 467 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 468 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 469 } 470 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 471 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 472 } 473 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 474 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 475 } 476 } 477 // Fill in signals that are blocked by all but the VM thread. 478 sigemptyset(&vm_sigs); 479 if (!ReduceSignalUsage) { 480 sigaddset(&vm_sigs, BREAK_SIGNAL); 481 } 482 debug_only(signal_sets_initialized = true); 483 484 } 485 486 // These are signals that are unblocked while a thread is running Java. 487 // (For some reason, they get blocked by default.) 488 sigset_t* os::Linux::unblocked_signals() { 489 assert(signal_sets_initialized, "Not initialized"); 490 return &unblocked_sigs; 491 } 492 493 // These are the signals that are blocked while a (non-VM) thread is 494 // running Java. Only the VM thread handles these signals. 495 sigset_t* os::Linux::vm_signals() { 496 assert(signal_sets_initialized, "Not initialized"); 497 return &vm_sigs; 498 } 499 500 void os::Linux::hotspot_sigmask(Thread* thread) { 501 502 //Save caller's signal mask before setting VM signal mask 503 sigset_t caller_sigmask; 504 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 505 506 OSThread* osthread = thread->osthread(); 507 osthread->set_caller_sigmask(caller_sigmask); 508 509 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 510 511 if (!ReduceSignalUsage) { 512 if (thread->is_VM_thread()) { 513 // Only the VM thread handles BREAK_SIGNAL ... 514 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 515 } else { 516 // ... all other threads block BREAK_SIGNAL 517 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 518 } 519 } 520 } 521 522 ////////////////////////////////////////////////////////////////////////////// 523 // detecting pthread library 524 525 void os::Linux::libpthread_init() { 526 // Save glibc and pthread version strings. 527 #if !defined(_CS_GNU_LIBC_VERSION) || \ 528 !defined(_CS_GNU_LIBPTHREAD_VERSION) 529 #error "glibc too old (< 2.3.2)" 530 #endif 531 532 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 533 assert(n > 0, "cannot retrieve glibc version"); 534 char *str = (char *)malloc(n, mtInternal); 535 confstr(_CS_GNU_LIBC_VERSION, str, n); 536 os::Linux::set_glibc_version(str); 537 538 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 539 assert(n > 0, "cannot retrieve pthread version"); 540 str = (char *)malloc(n, mtInternal); 541 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 542 os::Linux::set_libpthread_version(str); 543 } 544 545 ///////////////////////////////////////////////////////////////////////////// 546 // thread stack expansion 547 548 // os::Linux::manually_expand_stack() takes care of expanding the thread 549 // stack. Note that this is normally not needed: pthread stacks allocate 550 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 551 // committed. Therefore it is not necessary to expand the stack manually. 552 // 553 // Manually expanding the stack was historically needed on LinuxThreads 554 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 555 // it is kept to deal with very rare corner cases: 556 // 557 // For one, user may run the VM on an own implementation of threads 558 // whose stacks are - like the old LinuxThreads - implemented using 559 // mmap(MAP_GROWSDOWN). 560 // 561 // Also, this coding may be needed if the VM is running on the primordial 562 // thread. Normally we avoid running on the primordial thread; however, 563 // user may still invoke the VM on the primordial thread. 564 // 565 // The following historical comment describes the details about running 566 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 567 568 569 // Force Linux kernel to expand current thread stack. If "bottom" is close 570 // to the stack guard, caller should block all signals. 571 // 572 // MAP_GROWSDOWN: 573 // A special mmap() flag that is used to implement thread stacks. It tells 574 // kernel that the memory region should extend downwards when needed. This 575 // allows early versions of LinuxThreads to only mmap the first few pages 576 // when creating a new thread. Linux kernel will automatically expand thread 577 // stack as needed (on page faults). 578 // 579 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 580 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 581 // region, it's hard to tell if the fault is due to a legitimate stack 582 // access or because of reading/writing non-exist memory (e.g. buffer 583 // overrun). As a rule, if the fault happens below current stack pointer, 584 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 585 // application (see Linux kernel fault.c). 586 // 587 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 588 // stack overflow detection. 589 // 590 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 591 // not use MAP_GROWSDOWN. 592 // 593 // To get around the problem and allow stack banging on Linux, we need to 594 // manually expand thread stack after receiving the SIGSEGV. 595 // 596 // There are two ways to expand thread stack to address "bottom", we used 597 // both of them in JVM before 1.5: 598 // 1. adjust stack pointer first so that it is below "bottom", and then 599 // touch "bottom" 600 // 2. mmap() the page in question 601 // 602 // Now alternate signal stack is gone, it's harder to use 2. For instance, 603 // if current sp is already near the lower end of page 101, and we need to 604 // call mmap() to map page 100, it is possible that part of the mmap() frame 605 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 606 // That will destroy the mmap() frame and cause VM to crash. 607 // 608 // The following code works by adjusting sp first, then accessing the "bottom" 609 // page to force a page fault. Linux kernel will then automatically expand the 610 // stack mapping. 611 // 612 // _expand_stack_to() assumes its frame size is less than page size, which 613 // should always be true if the function is not inlined. 614 615 static void NOINLINE _expand_stack_to(address bottom) { 616 address sp; 617 size_t size; 618 volatile char *p; 619 620 // Adjust bottom to point to the largest address within the same page, it 621 // gives us a one-page buffer if alloca() allocates slightly more memory. 622 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 623 bottom += os::Linux::page_size() - 1; 624 625 // sp might be slightly above current stack pointer; if that's the case, we 626 // will alloca() a little more space than necessary, which is OK. Don't use 627 // os::current_stack_pointer(), as its result can be slightly below current 628 // stack pointer, causing us to not alloca enough to reach "bottom". 629 sp = (address)&sp; 630 631 if (sp > bottom) { 632 size = sp - bottom; 633 p = (volatile char *)alloca(size); 634 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 635 p[0] = '\0'; 636 } 637 } 638 639 void os::Linux::expand_stack_to(address bottom) { 640 _expand_stack_to(bottom); 641 } 642 643 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 644 assert(t!=NULL, "just checking"); 645 assert(t->osthread()->expanding_stack(), "expand should be set"); 646 assert(t->stack_base() != NULL, "stack_base was not initialized"); 647 648 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 649 sigset_t mask_all, old_sigset; 650 sigfillset(&mask_all); 651 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 652 _expand_stack_to(addr); 653 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 654 return true; 655 } 656 return false; 657 } 658 659 ////////////////////////////////////////////////////////////////////////////// 660 // create new thread 661 662 // Thread start routine for all newly created threads 663 static void *thread_native_entry(Thread *thread) { 664 // Try to randomize the cache line index of hot stack frames. 665 // This helps when threads of the same stack traces evict each other's 666 // cache lines. The threads can be either from the same JVM instance, or 667 // from different JVM instances. The benefit is especially true for 668 // processors with hyperthreading technology. 669 static int counter = 0; 670 int pid = os::current_process_id(); 671 alloca(((pid ^ counter++) & 7) * 128); 672 673 thread->initialize_thread_current(); 674 675 OSThread* osthread = thread->osthread(); 676 Monitor* sync = osthread->startThread_lock(); 677 678 osthread->set_thread_id(os::current_thread_id()); 679 680 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 681 os::current_thread_id(), (uintx) pthread_self()); 682 683 if (UseNUMA) { 684 int lgrp_id = os::numa_get_group_id(); 685 if (lgrp_id != -1) { 686 thread->set_lgrp_id(lgrp_id); 687 } 688 } 689 // initialize signal mask for this thread 690 os::Linux::hotspot_sigmask(thread); 691 692 // initialize floating point control register 693 os::Linux::init_thread_fpu_state(); 694 695 // handshaking with parent thread 696 { 697 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 698 699 // notify parent thread 700 osthread->set_state(INITIALIZED); 701 sync->notify_all(); 702 703 // wait until os::start_thread() 704 while (osthread->get_state() == INITIALIZED) { 705 sync->wait(Mutex::_no_safepoint_check_flag); 706 } 707 } 708 709 // call one more level start routine 710 thread->run(); 711 712 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 713 os::current_thread_id(), (uintx) pthread_self()); 714 715 // If a thread has not deleted itself ("delete this") as part of its 716 // termination sequence, we have to ensure thread-local-storage is 717 // cleared before we actually terminate. No threads should ever be 718 // deleted asynchronously with respect to their termination. 719 if (Thread::current_or_null_safe() != NULL) { 720 assert(Thread::current_or_null_safe() == thread, "current thread is wrong"); 721 thread->clear_thread_current(); 722 } 723 724 return 0; 725 } 726 727 bool os::create_thread(Thread* thread, ThreadType thr_type, 728 size_t req_stack_size) { 729 assert(thread->osthread() == NULL, "caller responsible"); 730 731 // Allocate the OSThread object 732 OSThread* osthread = new OSThread(NULL, NULL); 733 if (osthread == NULL) { 734 return false; 735 } 736 737 // set the correct thread state 738 osthread->set_thread_type(thr_type); 739 740 // Initial state is ALLOCATED but not INITIALIZED 741 osthread->set_state(ALLOCATED); 742 743 thread->set_osthread(osthread); 744 745 // init thread attributes 746 pthread_attr_t attr; 747 pthread_attr_init(&attr); 748 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 749 750 // Calculate stack size if it's not specified by caller. 751 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 752 // In the Linux NPTL pthread implementation the guard size mechanism 753 // is not implemented properly. The posix standard requires adding 754 // the size of the guard pages to the stack size, instead Linux 755 // takes the space out of 'stacksize'. Thus we adapt the requested 756 // stack_size by the size of the guard pages to mimick proper 757 // behaviour. However, be careful not to end up with a size 758 // of zero due to overflow. Don't add the guard page in that case. 759 size_t guard_size = os::Linux::default_guard_size(thr_type); 760 if (stack_size <= SIZE_MAX - guard_size) { 761 stack_size += guard_size; 762 } 763 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 764 765 int status = pthread_attr_setstacksize(&attr, stack_size); 766 assert_status(status == 0, status, "pthread_attr_setstacksize"); 767 768 // Configure glibc guard page. 769 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 770 771 ThreadState state; 772 773 { 774 pthread_t tid; 775 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 776 777 char buf[64]; 778 if (ret == 0) { 779 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 780 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 781 } else { 782 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 783 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 784 } 785 786 pthread_attr_destroy(&attr); 787 788 if (ret != 0) { 789 // Need to clean up stuff we've allocated so far 790 thread->set_osthread(NULL); 791 delete osthread; 792 return false; 793 } 794 795 // Store pthread info into the OSThread 796 osthread->set_pthread_id(tid); 797 798 // Wait until child thread is either initialized or aborted 799 { 800 Monitor* sync_with_child = osthread->startThread_lock(); 801 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 802 while ((state = osthread->get_state()) == ALLOCATED) { 803 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 804 } 805 } 806 } 807 808 // Aborted due to thread limit being reached 809 if (state == ZOMBIE) { 810 thread->set_osthread(NULL); 811 delete osthread; 812 return false; 813 } 814 815 // The thread is returned suspended (in state INITIALIZED), 816 // and is started higher up in the call chain 817 assert(state == INITIALIZED, "race condition"); 818 return true; 819 } 820 821 ///////////////////////////////////////////////////////////////////////////// 822 // attach existing thread 823 824 // bootstrap the main thread 825 bool os::create_main_thread(JavaThread* thread) { 826 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 827 return create_attached_thread(thread); 828 } 829 830 bool os::create_attached_thread(JavaThread* thread) { 831 #ifdef ASSERT 832 thread->verify_not_published(); 833 #endif 834 835 // Allocate the OSThread object 836 OSThread* osthread = new OSThread(NULL, NULL); 837 838 if (osthread == NULL) { 839 return false; 840 } 841 842 // Store pthread info into the OSThread 843 osthread->set_thread_id(os::Linux::gettid()); 844 osthread->set_pthread_id(::pthread_self()); 845 846 // initialize floating point control register 847 os::Linux::init_thread_fpu_state(); 848 849 // Initial thread state is RUNNABLE 850 osthread->set_state(RUNNABLE); 851 852 thread->set_osthread(osthread); 853 854 if (UseNUMA) { 855 int lgrp_id = os::numa_get_group_id(); 856 if (lgrp_id != -1) { 857 thread->set_lgrp_id(lgrp_id); 858 } 859 } 860 861 if (os::is_primordial_thread()) { 862 // If current thread is primordial thread, its stack is mapped on demand, 863 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 864 // the entire stack region to avoid SEGV in stack banging. 865 // It is also useful to get around the heap-stack-gap problem on SuSE 866 // kernel (see 4821821 for details). We first expand stack to the top 867 // of yellow zone, then enable stack yellow zone (order is significant, 868 // enabling yellow zone first will crash JVM on SuSE Linux), so there 869 // is no gap between the last two virtual memory regions. 870 871 JavaThread *jt = (JavaThread *)thread; 872 address addr = jt->stack_reserved_zone_base(); 873 assert(addr != NULL, "initialization problem?"); 874 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 875 876 osthread->set_expanding_stack(); 877 os::Linux::manually_expand_stack(jt, addr); 878 osthread->clear_expanding_stack(); 879 } 880 881 // initialize signal mask for this thread 882 // and save the caller's signal mask 883 os::Linux::hotspot_sigmask(thread); 884 885 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 886 os::current_thread_id(), (uintx) pthread_self()); 887 888 return true; 889 } 890 891 void os::pd_start_thread(Thread* thread) { 892 OSThread * osthread = thread->osthread(); 893 assert(osthread->get_state() != INITIALIZED, "just checking"); 894 Monitor* sync_with_child = osthread->startThread_lock(); 895 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 896 sync_with_child->notify(); 897 } 898 899 // Free Linux resources related to the OSThread 900 void os::free_thread(OSThread* osthread) { 901 assert(osthread != NULL, "osthread not set"); 902 903 // We are told to free resources of the argument thread, 904 // but we can only really operate on the current thread. 905 assert(Thread::current()->osthread() == osthread, 906 "os::free_thread but not current thread"); 907 908 #ifdef ASSERT 909 sigset_t current; 910 sigemptyset(¤t); 911 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 912 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 913 #endif 914 915 // Restore caller's signal mask 916 sigset_t sigmask = osthread->caller_sigmask(); 917 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 918 919 delete osthread; 920 } 921 922 ////////////////////////////////////////////////////////////////////////////// 923 // primordial thread 924 925 // Check if current thread is the primordial thread, similar to Solaris thr_main. 926 bool os::is_primordial_thread(void) { 927 if (suppress_primordial_thread_resolution) { 928 return false; 929 } 930 char dummy; 931 // If called before init complete, thread stack bottom will be null. 932 // Can be called if fatal error occurs before initialization. 933 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 934 assert(os::Linux::initial_thread_stack_bottom() != NULL && 935 os::Linux::initial_thread_stack_size() != 0, 936 "os::init did not locate primordial thread's stack region"); 937 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 938 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 939 os::Linux::initial_thread_stack_size()) { 940 return true; 941 } else { 942 return false; 943 } 944 } 945 946 // Find the virtual memory area that contains addr 947 static bool find_vma(address addr, address* vma_low, address* vma_high) { 948 FILE *fp = fopen("/proc/self/maps", "r"); 949 if (fp) { 950 address low, high; 951 while (!feof(fp)) { 952 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 953 if (low <= addr && addr < high) { 954 if (vma_low) *vma_low = low; 955 if (vma_high) *vma_high = high; 956 fclose(fp); 957 return true; 958 } 959 } 960 for (;;) { 961 int ch = fgetc(fp); 962 if (ch == EOF || ch == (int)'\n') break; 963 } 964 } 965 fclose(fp); 966 } 967 return false; 968 } 969 970 // Locate primordial thread stack. This special handling of primordial thread stack 971 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 972 // bogus value for the primordial process thread. While the launcher has created 973 // the VM in a new thread since JDK 6, we still have to allow for the use of the 974 // JNI invocation API from a primordial thread. 975 void os::Linux::capture_initial_stack(size_t max_size) { 976 977 // max_size is either 0 (which means accept OS default for thread stacks) or 978 // a user-specified value known to be at least the minimum needed. If we 979 // are actually on the primordial thread we can make it appear that we have a 980 // smaller max_size stack by inserting the guard pages at that location. But we 981 // cannot do anything to emulate a larger stack than what has been provided by 982 // the OS or threading library. In fact if we try to use a stack greater than 983 // what is set by rlimit then we will crash the hosting process. 984 985 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 986 // If this is "unlimited" then it will be a huge value. 987 struct rlimit rlim; 988 getrlimit(RLIMIT_STACK, &rlim); 989 size_t stack_size = rlim.rlim_cur; 990 991 // 6308388: a bug in ld.so will relocate its own .data section to the 992 // lower end of primordial stack; reduce ulimit -s value a little bit 993 // so we won't install guard page on ld.so's data section. 994 // But ensure we don't underflow the stack size - allow 1 page spare 995 if (stack_size >= (size_t)(3 * page_size())) { 996 stack_size -= 2 * page_size(); 997 } 998 999 // Try to figure out where the stack base (top) is. This is harder. 1000 // 1001 // When an application is started, glibc saves the initial stack pointer in 1002 // a global variable "__libc_stack_end", which is then used by system 1003 // libraries. __libc_stack_end should be pretty close to stack top. The 1004 // variable is available since the very early days. However, because it is 1005 // a private interface, it could disappear in the future. 1006 // 1007 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1008 // to __libc_stack_end, it is very close to stack top, but isn't the real 1009 // stack top. Note that /proc may not exist if VM is running as a chroot 1010 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1011 // /proc/<pid>/stat could change in the future (though unlikely). 1012 // 1013 // We try __libc_stack_end first. If that doesn't work, look for 1014 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1015 // as a hint, which should work well in most cases. 1016 1017 uintptr_t stack_start; 1018 1019 // try __libc_stack_end first 1020 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1021 if (p && *p) { 1022 stack_start = *p; 1023 } else { 1024 // see if we can get the start_stack field from /proc/self/stat 1025 FILE *fp; 1026 int pid; 1027 char state; 1028 int ppid; 1029 int pgrp; 1030 int session; 1031 int nr; 1032 int tpgrp; 1033 unsigned long flags; 1034 unsigned long minflt; 1035 unsigned long cminflt; 1036 unsigned long majflt; 1037 unsigned long cmajflt; 1038 unsigned long utime; 1039 unsigned long stime; 1040 long cutime; 1041 long cstime; 1042 long prio; 1043 long nice; 1044 long junk; 1045 long it_real; 1046 uintptr_t start; 1047 uintptr_t vsize; 1048 intptr_t rss; 1049 uintptr_t rsslim; 1050 uintptr_t scodes; 1051 uintptr_t ecode; 1052 int i; 1053 1054 // Figure what the primordial thread stack base is. Code is inspired 1055 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1056 // followed by command name surrounded by parentheses, state, etc. 1057 char stat[2048]; 1058 int statlen; 1059 1060 fp = fopen("/proc/self/stat", "r"); 1061 if (fp) { 1062 statlen = fread(stat, 1, 2047, fp); 1063 stat[statlen] = '\0'; 1064 fclose(fp); 1065 1066 // Skip pid and the command string. Note that we could be dealing with 1067 // weird command names, e.g. user could decide to rename java launcher 1068 // to "java 1.4.2 :)", then the stat file would look like 1069 // 1234 (java 1.4.2 :)) R ... ... 1070 // We don't really need to know the command string, just find the last 1071 // occurrence of ")" and then start parsing from there. See bug 4726580. 1072 char * s = strrchr(stat, ')'); 1073 1074 i = 0; 1075 if (s) { 1076 // Skip blank chars 1077 do { s++; } while (s && isspace(*s)); 1078 1079 #define _UFM UINTX_FORMAT 1080 #define _DFM INTX_FORMAT 1081 1082 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1083 // 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 1084 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, 1085 &state, // 3 %c 1086 &ppid, // 4 %d 1087 &pgrp, // 5 %d 1088 &session, // 6 %d 1089 &nr, // 7 %d 1090 &tpgrp, // 8 %d 1091 &flags, // 9 %lu 1092 &minflt, // 10 %lu 1093 &cminflt, // 11 %lu 1094 &majflt, // 12 %lu 1095 &cmajflt, // 13 %lu 1096 &utime, // 14 %lu 1097 &stime, // 15 %lu 1098 &cutime, // 16 %ld 1099 &cstime, // 17 %ld 1100 &prio, // 18 %ld 1101 &nice, // 19 %ld 1102 &junk, // 20 %ld 1103 &it_real, // 21 %ld 1104 &start, // 22 UINTX_FORMAT 1105 &vsize, // 23 UINTX_FORMAT 1106 &rss, // 24 INTX_FORMAT 1107 &rsslim, // 25 UINTX_FORMAT 1108 &scodes, // 26 UINTX_FORMAT 1109 &ecode, // 27 UINTX_FORMAT 1110 &stack_start); // 28 UINTX_FORMAT 1111 } 1112 1113 #undef _UFM 1114 #undef _DFM 1115 1116 if (i != 28 - 2) { 1117 assert(false, "Bad conversion from /proc/self/stat"); 1118 // product mode - assume we are the primordial thread, good luck in the 1119 // embedded case. 1120 warning("Can't detect primordial thread stack location - bad conversion"); 1121 stack_start = (uintptr_t) &rlim; 1122 } 1123 } else { 1124 // For some reason we can't open /proc/self/stat (for example, running on 1125 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1126 // most cases, so don't abort: 1127 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1128 stack_start = (uintptr_t) &rlim; 1129 } 1130 } 1131 1132 // Now we have a pointer (stack_start) very close to the stack top, the 1133 // next thing to do is to figure out the exact location of stack top. We 1134 // can find out the virtual memory area that contains stack_start by 1135 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1136 // and its upper limit is the real stack top. (again, this would fail if 1137 // running inside chroot, because /proc may not exist.) 1138 1139 uintptr_t stack_top; 1140 address low, high; 1141 if (find_vma((address)stack_start, &low, &high)) { 1142 // success, "high" is the true stack top. (ignore "low", because initial 1143 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1144 stack_top = (uintptr_t)high; 1145 } else { 1146 // failed, likely because /proc/self/maps does not exist 1147 warning("Can't detect primordial thread stack location - find_vma failed"); 1148 // best effort: stack_start is normally within a few pages below the real 1149 // stack top, use it as stack top, and reduce stack size so we won't put 1150 // guard page outside stack. 1151 stack_top = stack_start; 1152 stack_size -= 16 * page_size(); 1153 } 1154 1155 // stack_top could be partially down the page so align it 1156 stack_top = align_up(stack_top, page_size()); 1157 1158 // Allowed stack value is minimum of max_size and what we derived from rlimit 1159 if (max_size > 0) { 1160 _initial_thread_stack_size = MIN2(max_size, stack_size); 1161 } else { 1162 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1163 // clamp it at 8MB as we do on Solaris 1164 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1165 } 1166 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1167 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1168 1169 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1170 1171 if (log_is_enabled(Info, os, thread)) { 1172 // See if we seem to be on primordial process thread 1173 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1174 uintptr_t(&rlim) < stack_top; 1175 1176 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1177 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1178 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1179 stack_top, intptr_t(_initial_thread_stack_bottom)); 1180 } 1181 } 1182 1183 //////////////////////////////////////////////////////////////////////////////// 1184 // time support 1185 1186 // Time since start-up in seconds to a fine granularity. 1187 // Used by VMSelfDestructTimer and the MemProfiler. 1188 double os::elapsedTime() { 1189 1190 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1191 } 1192 1193 jlong os::elapsed_counter() { 1194 return javaTimeNanos() - initial_time_count; 1195 } 1196 1197 jlong os::elapsed_frequency() { 1198 return NANOSECS_PER_SEC; // nanosecond resolution 1199 } 1200 1201 bool os::supports_vtime() { return true; } 1202 bool os::enable_vtime() { return false; } 1203 bool os::vtime_enabled() { return false; } 1204 1205 double os::elapsedVTime() { 1206 struct rusage usage; 1207 int retval = getrusage(RUSAGE_THREAD, &usage); 1208 if (retval == 0) { 1209 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); 1210 } else { 1211 // better than nothing, but not much 1212 return elapsedTime(); 1213 } 1214 } 1215 1216 jlong os::javaTimeMillis() { 1217 timeval time; 1218 int status = gettimeofday(&time, NULL); 1219 assert(status != -1, "linux error"); 1220 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1221 } 1222 1223 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1224 timeval time; 1225 int status = gettimeofday(&time, NULL); 1226 assert(status != -1, "linux error"); 1227 seconds = jlong(time.tv_sec); 1228 nanos = jlong(time.tv_usec) * 1000; 1229 } 1230 1231 1232 #ifndef CLOCK_MONOTONIC 1233 #define CLOCK_MONOTONIC (1) 1234 #endif 1235 1236 void os::Linux::clock_init() { 1237 // we do dlopen's in this particular order due to bug in linux 1238 // dynamical loader (see 6348968) leading to crash on exit 1239 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1240 if (handle == NULL) { 1241 handle = dlopen("librt.so", RTLD_LAZY); 1242 } 1243 1244 if (handle) { 1245 int (*clock_getres_func)(clockid_t, struct timespec*) = 1246 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1247 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1248 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1249 if (clock_getres_func && clock_gettime_func) { 1250 // See if monotonic clock is supported by the kernel. Note that some 1251 // early implementations simply return kernel jiffies (updated every 1252 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1253 // for nano time (though the monotonic property is still nice to have). 1254 // It's fixed in newer kernels, however clock_getres() still returns 1255 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1256 // resolution for now. Hopefully as people move to new kernels, this 1257 // won't be a problem. 1258 struct timespec res; 1259 struct timespec tp; 1260 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1261 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1262 // yes, monotonic clock is supported 1263 _clock_gettime = clock_gettime_func; 1264 return; 1265 } else { 1266 // close librt if there is no monotonic clock 1267 dlclose(handle); 1268 } 1269 } 1270 } 1271 warning("No monotonic clock was available - timed services may " \ 1272 "be adversely affected if the time-of-day clock changes"); 1273 } 1274 1275 #ifndef SYS_clock_getres 1276 #if defined(X86) || defined(PPC64) || defined(S390) 1277 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261) 1278 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1279 #else 1280 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1281 #define sys_clock_getres(x,y) -1 1282 #endif 1283 #else 1284 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1285 #endif 1286 1287 void os::Linux::fast_thread_clock_init() { 1288 if (!UseLinuxPosixThreadCPUClocks) { 1289 return; 1290 } 1291 clockid_t clockid; 1292 struct timespec tp; 1293 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1294 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1295 1296 // Switch to using fast clocks for thread cpu time if 1297 // the sys_clock_getres() returns 0 error code. 1298 // Note, that some kernels may support the current thread 1299 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1300 // returned by the pthread_getcpuclockid(). 1301 // If the fast Posix clocks are supported then the sys_clock_getres() 1302 // must return at least tp.tv_sec == 0 which means a resolution 1303 // better than 1 sec. This is extra check for reliability. 1304 1305 if (pthread_getcpuclockid_func && 1306 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1307 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1308 _supports_fast_thread_cpu_time = true; 1309 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1310 } 1311 } 1312 1313 jlong os::javaTimeNanos() { 1314 if (os::supports_monotonic_clock()) { 1315 struct timespec tp; 1316 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1317 assert(status == 0, "gettime error"); 1318 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1319 return result; 1320 } else { 1321 timeval time; 1322 int status = gettimeofday(&time, NULL); 1323 assert(status != -1, "linux error"); 1324 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1325 return 1000 * usecs; 1326 } 1327 } 1328 1329 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1330 if (os::supports_monotonic_clock()) { 1331 info_ptr->max_value = ALL_64_BITS; 1332 1333 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1334 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1335 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1336 } else { 1337 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1338 info_ptr->max_value = ALL_64_BITS; 1339 1340 // gettimeofday is a real time clock so it skips 1341 info_ptr->may_skip_backward = true; 1342 info_ptr->may_skip_forward = true; 1343 } 1344 1345 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1346 } 1347 1348 // Return the real, user, and system times in seconds from an 1349 // arbitrary fixed point in the past. 1350 bool os::getTimesSecs(double* process_real_time, 1351 double* process_user_time, 1352 double* process_system_time) { 1353 struct tms ticks; 1354 clock_t real_ticks = times(&ticks); 1355 1356 if (real_ticks == (clock_t) (-1)) { 1357 return false; 1358 } else { 1359 double ticks_per_second = (double) clock_tics_per_sec; 1360 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1361 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1362 *process_real_time = ((double) real_ticks) / ticks_per_second; 1363 1364 return true; 1365 } 1366 } 1367 1368 1369 char * os::local_time_string(char *buf, size_t buflen) { 1370 struct tm t; 1371 time_t long_time; 1372 time(&long_time); 1373 localtime_r(&long_time, &t); 1374 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1375 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1376 t.tm_hour, t.tm_min, t.tm_sec); 1377 return buf; 1378 } 1379 1380 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1381 return localtime_r(clock, res); 1382 } 1383 1384 //////////////////////////////////////////////////////////////////////////////// 1385 // runtime exit support 1386 1387 // Note: os::shutdown() might be called very early during initialization, or 1388 // called from signal handler. Before adding something to os::shutdown(), make 1389 // sure it is async-safe and can handle partially initialized VM. 1390 void os::shutdown() { 1391 1392 // allow PerfMemory to attempt cleanup of any persistent resources 1393 perfMemory_exit(); 1394 1395 // needs to remove object in file system 1396 AttachListener::abort(); 1397 1398 // flush buffered output, finish log files 1399 ostream_abort(); 1400 1401 // Check for abort hook 1402 abort_hook_t abort_hook = Arguments::abort_hook(); 1403 if (abort_hook != NULL) { 1404 abort_hook(); 1405 } 1406 1407 } 1408 1409 // Note: os::abort() might be called very early during initialization, or 1410 // called from signal handler. Before adding something to os::abort(), make 1411 // sure it is async-safe and can handle partially initialized VM. 1412 void os::abort(bool dump_core, void* siginfo, const void* context) { 1413 os::shutdown(); 1414 if (dump_core) { 1415 #ifndef PRODUCT 1416 fdStream out(defaultStream::output_fd()); 1417 out.print_raw("Current thread is "); 1418 char buf[16]; 1419 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1420 out.print_raw_cr(buf); 1421 out.print_raw_cr("Dumping core ..."); 1422 #endif 1423 ::abort(); // dump core 1424 } 1425 1426 ::exit(1); 1427 } 1428 1429 // Die immediately, no exit hook, no abort hook, no cleanup. 1430 void os::die() { 1431 ::abort(); 1432 } 1433 1434 1435 // This method is a copy of JDK's sysGetLastErrorString 1436 // from src/solaris/hpi/src/system_md.c 1437 1438 size_t os::lasterror(char *buf, size_t len) { 1439 if (errno == 0) return 0; 1440 1441 const char *s = os::strerror(errno); 1442 size_t n = ::strlen(s); 1443 if (n >= len) { 1444 n = len - 1; 1445 } 1446 ::strncpy(buf, s, n); 1447 buf[n] = '\0'; 1448 return n; 1449 } 1450 1451 // thread_id is kernel thread id (similar to Solaris LWP id) 1452 intx os::current_thread_id() { return os::Linux::gettid(); } 1453 int os::current_process_id() { 1454 return ::getpid(); 1455 } 1456 1457 // DLL functions 1458 1459 const char* os::dll_file_extension() { return ".so"; } 1460 1461 // This must be hard coded because it's the system's temporary 1462 // directory not the java application's temp directory, ala java.io.tmpdir. 1463 const char* os::get_temp_directory() { return "/tmp"; } 1464 1465 static bool file_exists(const char* filename) { 1466 struct stat statbuf; 1467 if (filename == NULL || strlen(filename) == 0) { 1468 return false; 1469 } 1470 return os::stat(filename, &statbuf) == 0; 1471 } 1472 1473 // check if addr is inside libjvm.so 1474 bool os::address_is_in_vm(address addr) { 1475 static address libjvm_base_addr; 1476 Dl_info dlinfo; 1477 1478 if (libjvm_base_addr == NULL) { 1479 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1480 libjvm_base_addr = (address)dlinfo.dli_fbase; 1481 } 1482 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1483 } 1484 1485 if (dladdr((void *)addr, &dlinfo) != 0) { 1486 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1487 } 1488 1489 return false; 1490 } 1491 1492 bool os::dll_address_to_function_name(address addr, char *buf, 1493 int buflen, int *offset, 1494 bool demangle) { 1495 // buf is not optional, but offset is optional 1496 assert(buf != NULL, "sanity check"); 1497 1498 Dl_info dlinfo; 1499 1500 if (dladdr((void*)addr, &dlinfo) != 0) { 1501 // see if we have a matching symbol 1502 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1503 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1504 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1505 } 1506 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1507 return true; 1508 } 1509 // no matching symbol so try for just file info 1510 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1511 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1512 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1513 return true; 1514 } 1515 } 1516 } 1517 1518 buf[0] = '\0'; 1519 if (offset != NULL) *offset = -1; 1520 return false; 1521 } 1522 1523 struct _address_to_library_name { 1524 address addr; // input : memory address 1525 size_t buflen; // size of fname 1526 char* fname; // output: library name 1527 address base; // library base addr 1528 }; 1529 1530 static int address_to_library_name_callback(struct dl_phdr_info *info, 1531 size_t size, void *data) { 1532 int i; 1533 bool found = false; 1534 address libbase = NULL; 1535 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1536 1537 // iterate through all loadable segments 1538 for (i = 0; i < info->dlpi_phnum; i++) { 1539 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1540 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1541 // base address of a library is the lowest address of its loaded 1542 // segments. 1543 if (libbase == NULL || libbase > segbase) { 1544 libbase = segbase; 1545 } 1546 // see if 'addr' is within current segment 1547 if (segbase <= d->addr && 1548 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1549 found = true; 1550 } 1551 } 1552 } 1553 1554 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1555 // so dll_address_to_library_name() can fall through to use dladdr() which 1556 // can figure out executable name from argv[0]. 1557 if (found && info->dlpi_name && info->dlpi_name[0]) { 1558 d->base = libbase; 1559 if (d->fname) { 1560 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1561 } 1562 return 1; 1563 } 1564 return 0; 1565 } 1566 1567 bool os::dll_address_to_library_name(address addr, char* buf, 1568 int buflen, int* offset) { 1569 // buf is not optional, but offset is optional 1570 assert(buf != NULL, "sanity check"); 1571 1572 Dl_info dlinfo; 1573 struct _address_to_library_name data; 1574 1575 // There is a bug in old glibc dladdr() implementation that it could resolve 1576 // to wrong library name if the .so file has a base address != NULL. Here 1577 // we iterate through the program headers of all loaded libraries to find 1578 // out which library 'addr' really belongs to. This workaround can be 1579 // removed once the minimum requirement for glibc is moved to 2.3.x. 1580 data.addr = addr; 1581 data.fname = buf; 1582 data.buflen = buflen; 1583 data.base = NULL; 1584 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1585 1586 if (rslt) { 1587 // buf already contains library name 1588 if (offset) *offset = addr - data.base; 1589 return true; 1590 } 1591 if (dladdr((void*)addr, &dlinfo) != 0) { 1592 if (dlinfo.dli_fname != NULL) { 1593 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1594 } 1595 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1596 *offset = addr - (address)dlinfo.dli_fbase; 1597 } 1598 return true; 1599 } 1600 1601 buf[0] = '\0'; 1602 if (offset) *offset = -1; 1603 return false; 1604 } 1605 1606 // Loads .dll/.so and 1607 // in case of error it checks if .dll/.so was built for the 1608 // same architecture as Hotspot is running on 1609 1610 1611 // Remember the stack's state. The Linux dynamic linker will change 1612 // the stack to 'executable' at most once, so we must safepoint only once. 1613 bool os::Linux::_stack_is_executable = false; 1614 1615 // VM operation that loads a library. This is necessary if stack protection 1616 // of the Java stacks can be lost during loading the library. If we 1617 // do not stop the Java threads, they can stack overflow before the stacks 1618 // are protected again. 1619 class VM_LinuxDllLoad: public VM_Operation { 1620 private: 1621 const char *_filename; 1622 char *_ebuf; 1623 int _ebuflen; 1624 void *_lib; 1625 public: 1626 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1627 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1628 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1629 void doit() { 1630 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1631 os::Linux::_stack_is_executable = true; 1632 } 1633 void* loaded_library() { return _lib; } 1634 }; 1635 1636 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1637 void * result = NULL; 1638 bool load_attempted = false; 1639 1640 // Check whether the library to load might change execution rights 1641 // of the stack. If they are changed, the protection of the stack 1642 // guard pages will be lost. We need a safepoint to fix this. 1643 // 1644 // See Linux man page execstack(8) for more info. 1645 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1646 if (!ElfFile::specifies_noexecstack(filename)) { 1647 if (!is_init_completed()) { 1648 os::Linux::_stack_is_executable = true; 1649 // This is OK - No Java threads have been created yet, and hence no 1650 // stack guard pages to fix. 1651 // 1652 // This should happen only when you are building JDK7 using a very 1653 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1654 // 1655 // Dynamic loader will make all stacks executable after 1656 // this function returns, and will not do that again. 1657 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1658 } else { 1659 warning("You have loaded library %s which might have disabled stack guard. " 1660 "The VM will try to fix the stack guard now.\n" 1661 "It's highly recommended that you fix the library with " 1662 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1663 filename); 1664 1665 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1666 JavaThread *jt = JavaThread::current(); 1667 if (jt->thread_state() != _thread_in_native) { 1668 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1669 // that requires ExecStack. Cannot enter safe point. Let's give up. 1670 warning("Unable to fix stack guard. Giving up."); 1671 } else { 1672 if (!LoadExecStackDllInVMThread) { 1673 // This is for the case where the DLL has an static 1674 // constructor function that executes JNI code. We cannot 1675 // load such DLLs in the VMThread. 1676 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1677 } 1678 1679 ThreadInVMfromNative tiv(jt); 1680 debug_only(VMNativeEntryWrapper vew;) 1681 1682 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1683 VMThread::execute(&op); 1684 if (LoadExecStackDllInVMThread) { 1685 result = op.loaded_library(); 1686 } 1687 load_attempted = true; 1688 } 1689 } 1690 } 1691 } 1692 1693 if (!load_attempted) { 1694 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1695 } 1696 1697 if (result != NULL) { 1698 // Successful loading 1699 return result; 1700 } 1701 1702 Elf32_Ehdr elf_head; 1703 int diag_msg_max_length=ebuflen-strlen(ebuf); 1704 char* diag_msg_buf=ebuf+strlen(ebuf); 1705 1706 if (diag_msg_max_length==0) { 1707 // No more space in ebuf for additional diagnostics message 1708 return NULL; 1709 } 1710 1711 1712 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1713 1714 if (file_descriptor < 0) { 1715 // Can't open library, report dlerror() message 1716 return NULL; 1717 } 1718 1719 bool failed_to_read_elf_head= 1720 (sizeof(elf_head)!= 1721 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1722 1723 ::close(file_descriptor); 1724 if (failed_to_read_elf_head) { 1725 // file i/o error - report dlerror() msg 1726 return NULL; 1727 } 1728 1729 typedef struct { 1730 Elf32_Half code; // Actual value as defined in elf.h 1731 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1732 unsigned char elf_class; // 32 or 64 bit 1733 unsigned char endianess; // MSB or LSB 1734 char* name; // String representation 1735 } arch_t; 1736 1737 #ifndef EM_486 1738 #define EM_486 6 /* Intel 80486 */ 1739 #endif 1740 #ifndef EM_AARCH64 1741 #define EM_AARCH64 183 /* ARM AARCH64 */ 1742 #endif 1743 1744 static const arch_t arch_array[]={ 1745 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1746 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1747 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1748 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1749 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1750 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1751 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1752 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1753 #if defined(VM_LITTLE_ENDIAN) 1754 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1755 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1756 #else 1757 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1758 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1759 #endif 1760 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1761 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1762 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1763 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1764 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1765 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1766 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1767 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1768 }; 1769 1770 #if (defined IA32) 1771 static Elf32_Half running_arch_code=EM_386; 1772 #elif (defined AMD64) 1773 static Elf32_Half running_arch_code=EM_X86_64; 1774 #elif (defined IA64) 1775 static Elf32_Half running_arch_code=EM_IA_64; 1776 #elif (defined __sparc) && (defined _LP64) 1777 static Elf32_Half running_arch_code=EM_SPARCV9; 1778 #elif (defined __sparc) && (!defined _LP64) 1779 static Elf32_Half running_arch_code=EM_SPARC; 1780 #elif (defined __powerpc64__) 1781 static Elf32_Half running_arch_code=EM_PPC64; 1782 #elif (defined __powerpc__) 1783 static Elf32_Half running_arch_code=EM_PPC; 1784 #elif (defined AARCH64) 1785 static Elf32_Half running_arch_code=EM_AARCH64; 1786 #elif (defined ARM) 1787 static Elf32_Half running_arch_code=EM_ARM; 1788 #elif (defined S390) 1789 static Elf32_Half running_arch_code=EM_S390; 1790 #elif (defined ALPHA) 1791 static Elf32_Half running_arch_code=EM_ALPHA; 1792 #elif (defined MIPSEL) 1793 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1794 #elif (defined PARISC) 1795 static Elf32_Half running_arch_code=EM_PARISC; 1796 #elif (defined MIPS) 1797 static Elf32_Half running_arch_code=EM_MIPS; 1798 #elif (defined M68K) 1799 static Elf32_Half running_arch_code=EM_68K; 1800 #elif (defined SH) 1801 static Elf32_Half running_arch_code=EM_SH; 1802 #else 1803 #error Method os::dll_load requires that one of following is defined:\ 1804 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc 1805 #endif 1806 1807 // Identify compatability class for VM's architecture and library's architecture 1808 // Obtain string descriptions for architectures 1809 1810 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1811 int running_arch_index=-1; 1812 1813 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1814 if (running_arch_code == arch_array[i].code) { 1815 running_arch_index = i; 1816 } 1817 if (lib_arch.code == arch_array[i].code) { 1818 lib_arch.compat_class = arch_array[i].compat_class; 1819 lib_arch.name = arch_array[i].name; 1820 } 1821 } 1822 1823 assert(running_arch_index != -1, 1824 "Didn't find running architecture code (running_arch_code) in arch_array"); 1825 if (running_arch_index == -1) { 1826 // Even though running architecture detection failed 1827 // we may still continue with reporting dlerror() message 1828 return NULL; 1829 } 1830 1831 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1832 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1833 return NULL; 1834 } 1835 1836 #ifndef S390 1837 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1838 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1839 return NULL; 1840 } 1841 #endif // !S390 1842 1843 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1844 if (lib_arch.name!=NULL) { 1845 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1846 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1847 lib_arch.name, arch_array[running_arch_index].name); 1848 } else { 1849 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1850 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1851 lib_arch.code, 1852 arch_array[running_arch_index].name); 1853 } 1854 } 1855 1856 return NULL; 1857 } 1858 1859 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1860 int ebuflen) { 1861 void * result = ::dlopen(filename, RTLD_LAZY); 1862 if (result == NULL) { 1863 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1864 ebuf[ebuflen-1] = '\0'; 1865 } 1866 return result; 1867 } 1868 1869 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1870 int ebuflen) { 1871 void * result = NULL; 1872 if (LoadExecStackDllInVMThread) { 1873 result = dlopen_helper(filename, ebuf, ebuflen); 1874 } 1875 1876 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1877 // library that requires an executable stack, or which does not have this 1878 // stack attribute set, dlopen changes the stack attribute to executable. The 1879 // read protection of the guard pages gets lost. 1880 // 1881 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1882 // may have been queued at the same time. 1883 1884 if (!_stack_is_executable) { 1885 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 1886 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1887 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1888 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1889 warning("Attempt to reguard stack yellow zone failed."); 1890 } 1891 } 1892 } 1893 } 1894 1895 return result; 1896 } 1897 1898 void* os::dll_lookup(void* handle, const char* name) { 1899 void* res = dlsym(handle, name); 1900 return res; 1901 } 1902 1903 void* os::get_default_process_handle() { 1904 return (void*)::dlopen(NULL, RTLD_LAZY); 1905 } 1906 1907 static bool _print_ascii_file(const char* filename, outputStream* st) { 1908 int fd = ::open(filename, O_RDONLY); 1909 if (fd == -1) { 1910 return false; 1911 } 1912 1913 char buf[33]; 1914 int bytes; 1915 buf[32] = '\0'; 1916 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1917 st->print_raw(buf, bytes); 1918 } 1919 1920 ::close(fd); 1921 1922 return true; 1923 } 1924 1925 void os::print_dll_info(outputStream *st) { 1926 st->print_cr("Dynamic libraries:"); 1927 1928 char fname[32]; 1929 pid_t pid = os::Linux::gettid(); 1930 1931 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1932 1933 if (!_print_ascii_file(fname, st)) { 1934 st->print("Can not get library information for pid = %d\n", pid); 1935 } 1936 } 1937 1938 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1939 FILE *procmapsFile = NULL; 1940 1941 // Open the procfs maps file for the current process 1942 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1943 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1944 char line[PATH_MAX + 100]; 1945 1946 // Read line by line from 'file' 1947 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1948 u8 base, top, offset, inode; 1949 char permissions[5]; 1950 char device[6]; 1951 char name[PATH_MAX + 1]; 1952 1953 // Parse fields from line 1954 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1955 &base, &top, permissions, &offset, device, &inode, name); 1956 1957 // Filter by device id '00:00' so that we only get file system mapped files. 1958 if (strcmp(device, "00:00") != 0) { 1959 1960 // Call callback with the fields of interest 1961 if(callback(name, (address)base, (address)top, param)) { 1962 // Oops abort, callback aborted 1963 fclose(procmapsFile); 1964 return 1; 1965 } 1966 } 1967 } 1968 fclose(procmapsFile); 1969 } 1970 return 0; 1971 } 1972 1973 void os::print_os_info_brief(outputStream* st) { 1974 os::Linux::print_distro_info(st); 1975 1976 os::Posix::print_uname_info(st); 1977 1978 os::Linux::print_libversion_info(st); 1979 1980 } 1981 1982 void os::print_os_info(outputStream* st) { 1983 st->print("OS:"); 1984 1985 os::Linux::print_distro_info(st); 1986 1987 os::Posix::print_uname_info(st); 1988 1989 // Print warning if unsafe chroot environment detected 1990 if (unsafe_chroot_detected) { 1991 st->print("WARNING!! "); 1992 st->print_cr("%s", unstable_chroot_error); 1993 } 1994 1995 os::Linux::print_libversion_info(st); 1996 1997 os::Posix::print_rlimit_info(st); 1998 1999 os::Posix::print_load_average(st); 2000 2001 os::Linux::print_full_memory_info(st); 2002 2003 os::Linux::print_container_info(st); 2004 } 2005 2006 // Try to identify popular distros. 2007 // Most Linux distributions have a /etc/XXX-release file, which contains 2008 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2009 // file that also contains the OS version string. Some have more than one 2010 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2011 // /etc/redhat-release.), so the order is important. 2012 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2013 // their own specific XXX-release file as well as a redhat-release file. 2014 // Because of this the XXX-release file needs to be searched for before the 2015 // redhat-release file. 2016 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2017 // search for redhat-release / SuSE-release needs to be before lsb-release. 2018 // Since the lsb-release file is the new standard it needs to be searched 2019 // before the older style release files. 2020 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2021 // next to last resort. The os-release file is a new standard that contains 2022 // distribution information and the system-release file seems to be an old 2023 // standard that has been replaced by the lsb-release and os-release files. 2024 // Searching for the debian_version file is the last resort. It contains 2025 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2026 // "Debian " is printed before the contents of the debian_version file. 2027 2028 const char* distro_files[] = { 2029 "/etc/oracle-release", 2030 "/etc/mandriva-release", 2031 "/etc/mandrake-release", 2032 "/etc/sun-release", 2033 "/etc/redhat-release", 2034 "/etc/SuSE-release", 2035 "/etc/lsb-release", 2036 "/etc/turbolinux-release", 2037 "/etc/gentoo-release", 2038 "/etc/ltib-release", 2039 "/etc/angstrom-version", 2040 "/etc/system-release", 2041 "/etc/os-release", 2042 NULL }; 2043 2044 void os::Linux::print_distro_info(outputStream* st) { 2045 for (int i = 0;; i++) { 2046 const char* file = distro_files[i]; 2047 if (file == NULL) { 2048 break; // done 2049 } 2050 // If file prints, we found it. 2051 if (_print_ascii_file(file, st)) { 2052 return; 2053 } 2054 } 2055 2056 if (file_exists("/etc/debian_version")) { 2057 st->print("Debian "); 2058 _print_ascii_file("/etc/debian_version", st); 2059 } else { 2060 st->print("Linux"); 2061 } 2062 st->cr(); 2063 } 2064 2065 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2066 char buf[256]; 2067 while (fgets(buf, sizeof(buf), fp)) { 2068 // Edit out extra stuff in expected format 2069 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2070 char* ptr = strstr(buf, "\""); // the name is in quotes 2071 if (ptr != NULL) { 2072 ptr++; // go beyond first quote 2073 char* nl = strchr(ptr, '\"'); 2074 if (nl != NULL) *nl = '\0'; 2075 strncpy(distro, ptr, length); 2076 } else { 2077 ptr = strstr(buf, "="); 2078 ptr++; // go beyond equals then 2079 char* nl = strchr(ptr, '\n'); 2080 if (nl != NULL) *nl = '\0'; 2081 strncpy(distro, ptr, length); 2082 } 2083 return; 2084 } else if (get_first_line) { 2085 char* nl = strchr(buf, '\n'); 2086 if (nl != NULL) *nl = '\0'; 2087 strncpy(distro, buf, length); 2088 return; 2089 } 2090 } 2091 // print last line and close 2092 char* nl = strchr(buf, '\n'); 2093 if (nl != NULL) *nl = '\0'; 2094 strncpy(distro, buf, length); 2095 } 2096 2097 static void parse_os_info(char* distro, size_t length, const char* file) { 2098 FILE* fp = fopen(file, "r"); 2099 if (fp != NULL) { 2100 // if suse format, print out first line 2101 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2102 parse_os_info_helper(fp, distro, length, get_first_line); 2103 fclose(fp); 2104 } 2105 } 2106 2107 void os::get_summary_os_info(char* buf, size_t buflen) { 2108 for (int i = 0;; i++) { 2109 const char* file = distro_files[i]; 2110 if (file == NULL) { 2111 break; // ran out of distro_files 2112 } 2113 if (file_exists(file)) { 2114 parse_os_info(buf, buflen, file); 2115 return; 2116 } 2117 } 2118 // special case for debian 2119 if (file_exists("/etc/debian_version")) { 2120 strncpy(buf, "Debian ", buflen); 2121 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2122 } else { 2123 strncpy(buf, "Linux", buflen); 2124 } 2125 } 2126 2127 void os::Linux::print_libversion_info(outputStream* st) { 2128 // libc, pthread 2129 st->print("libc:"); 2130 st->print("%s ", os::Linux::glibc_version()); 2131 st->print("%s ", os::Linux::libpthread_version()); 2132 st->cr(); 2133 } 2134 2135 void os::Linux::print_full_memory_info(outputStream* st) { 2136 st->print("\n/proc/meminfo:\n"); 2137 _print_ascii_file("/proc/meminfo", st); 2138 st->cr(); 2139 } 2140 2141 void os::Linux::print_container_info(outputStream* st) { 2142 if (!OSContainer::is_containerized()) { 2143 return; 2144 } 2145 2146 st->print("container (cgroup) information:\n"); 2147 2148 const char *p_ct = OSContainer::container_type(); 2149 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed"); 2150 2151 char *p = OSContainer::cpu_cpuset_cpus(); 2152 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed"); 2153 free(p); 2154 2155 p = OSContainer::cpu_cpuset_memory_nodes(); 2156 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed"); 2157 free(p); 2158 2159 int i = OSContainer::active_processor_count(); 2160 if (i > 0) { 2161 st->print("active_processor_count: %d\n", i); 2162 } else { 2163 st->print("active_processor_count: failed\n"); 2164 } 2165 2166 i = OSContainer::cpu_quota(); 2167 st->print("cpu_quota: %d\n", i); 2168 2169 i = OSContainer::cpu_period(); 2170 st->print("cpu_period: %d\n", i); 2171 2172 i = OSContainer::cpu_shares(); 2173 st->print("cpu_shares: %d\n", i); 2174 2175 jlong j = OSContainer::memory_limit_in_bytes(); 2176 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j); 2177 2178 j = OSContainer::memory_and_swap_limit_in_bytes(); 2179 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j); 2180 2181 j = OSContainer::memory_soft_limit_in_bytes(); 2182 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j); 2183 2184 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2185 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j); 2186 2187 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2188 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j); 2189 st->cr(); 2190 } 2191 2192 void os::print_memory_info(outputStream* st) { 2193 2194 st->print("Memory:"); 2195 st->print(" %dk page", os::vm_page_size()>>10); 2196 2197 // values in struct sysinfo are "unsigned long" 2198 struct sysinfo si; 2199 sysinfo(&si); 2200 2201 st->print(", physical " UINT64_FORMAT "k", 2202 os::physical_memory() >> 10); 2203 st->print("(" UINT64_FORMAT "k free)", 2204 os::available_memory() >> 10); 2205 st->print(", swap " UINT64_FORMAT "k", 2206 ((jlong)si.totalswap * si.mem_unit) >> 10); 2207 st->print("(" UINT64_FORMAT "k free)", 2208 ((jlong)si.freeswap * si.mem_unit) >> 10); 2209 st->cr(); 2210 } 2211 2212 // Print the first "model name" line and the first "flags" line 2213 // that we find and nothing more. We assume "model name" comes 2214 // before "flags" so if we find a second "model name", then the 2215 // "flags" field is considered missing. 2216 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2217 #if defined(IA32) || defined(AMD64) 2218 // Other platforms have less repetitive cpuinfo files 2219 FILE *fp = fopen("/proc/cpuinfo", "r"); 2220 if (fp) { 2221 while (!feof(fp)) { 2222 if (fgets(buf, buflen, fp)) { 2223 // Assume model name comes before flags 2224 bool model_name_printed = false; 2225 if (strstr(buf, "model name") != NULL) { 2226 if (!model_name_printed) { 2227 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2228 st->print_raw(buf); 2229 model_name_printed = true; 2230 } else { 2231 // model name printed but not flags? Odd, just return 2232 fclose(fp); 2233 return true; 2234 } 2235 } 2236 // print the flags line too 2237 if (strstr(buf, "flags") != NULL) { 2238 st->print_raw(buf); 2239 fclose(fp); 2240 return true; 2241 } 2242 } 2243 } 2244 fclose(fp); 2245 } 2246 #endif // x86 platforms 2247 return false; 2248 } 2249 2250 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2251 // Only print the model name if the platform provides this as a summary 2252 if (!print_model_name_and_flags(st, buf, buflen)) { 2253 st->print("\n/proc/cpuinfo:\n"); 2254 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2255 st->print_cr(" <Not Available>"); 2256 } 2257 } 2258 } 2259 2260 #if defined(AMD64) || defined(IA32) || defined(X32) 2261 const char* search_string = "model name"; 2262 #elif defined(M68K) 2263 const char* search_string = "CPU"; 2264 #elif defined(PPC64) 2265 const char* search_string = "cpu"; 2266 #elif defined(S390) 2267 const char* search_string = "processor"; 2268 #elif defined(SPARC) 2269 const char* search_string = "cpu"; 2270 #else 2271 const char* search_string = "Processor"; 2272 #endif 2273 2274 // Parses the cpuinfo file for string representing the model name. 2275 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2276 FILE* fp = fopen("/proc/cpuinfo", "r"); 2277 if (fp != NULL) { 2278 while (!feof(fp)) { 2279 char buf[256]; 2280 if (fgets(buf, sizeof(buf), fp)) { 2281 char* start = strstr(buf, search_string); 2282 if (start != NULL) { 2283 char *ptr = start + strlen(search_string); 2284 char *end = buf + strlen(buf); 2285 while (ptr != end) { 2286 // skip whitespace and colon for the rest of the name. 2287 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2288 break; 2289 } 2290 ptr++; 2291 } 2292 if (ptr != end) { 2293 // reasonable string, get rid of newline and keep the rest 2294 char* nl = strchr(buf, '\n'); 2295 if (nl != NULL) *nl = '\0'; 2296 strncpy(cpuinfo, ptr, length); 2297 fclose(fp); 2298 return; 2299 } 2300 } 2301 } 2302 } 2303 fclose(fp); 2304 } 2305 // cpuinfo not found or parsing failed, just print generic string. The entire 2306 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2307 #if defined(AARCH64) 2308 strncpy(cpuinfo, "AArch64", length); 2309 #elif defined(AMD64) 2310 strncpy(cpuinfo, "x86_64", length); 2311 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2312 strncpy(cpuinfo, "ARM", length); 2313 #elif defined(IA32) 2314 strncpy(cpuinfo, "x86_32", length); 2315 #elif defined(IA64) 2316 strncpy(cpuinfo, "IA64", length); 2317 #elif defined(PPC) 2318 strncpy(cpuinfo, "PPC64", length); 2319 #elif defined(S390) 2320 strncpy(cpuinfo, "S390", length); 2321 #elif defined(SPARC) 2322 strncpy(cpuinfo, "sparcv9", length); 2323 #elif defined(ZERO_LIBARCH) 2324 strncpy(cpuinfo, ZERO_LIBARCH, length); 2325 #else 2326 strncpy(cpuinfo, "unknown", length); 2327 #endif 2328 } 2329 2330 static void print_signal_handler(outputStream* st, int sig, 2331 char* buf, size_t buflen); 2332 2333 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2334 st->print_cr("Signal Handlers:"); 2335 print_signal_handler(st, SIGSEGV, buf, buflen); 2336 print_signal_handler(st, SIGBUS , buf, buflen); 2337 print_signal_handler(st, SIGFPE , buf, buflen); 2338 print_signal_handler(st, SIGPIPE, buf, buflen); 2339 print_signal_handler(st, SIGXFSZ, buf, buflen); 2340 print_signal_handler(st, SIGILL , buf, buflen); 2341 print_signal_handler(st, SR_signum, buf, buflen); 2342 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2343 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2344 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2345 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2346 #if defined(PPC64) 2347 print_signal_handler(st, SIGTRAP, buf, buflen); 2348 #endif 2349 } 2350 2351 static char saved_jvm_path[MAXPATHLEN] = {0}; 2352 2353 // Find the full path to the current module, libjvm.so 2354 void os::jvm_path(char *buf, jint buflen) { 2355 // Error checking. 2356 if (buflen < MAXPATHLEN) { 2357 assert(false, "must use a large-enough buffer"); 2358 buf[0] = '\0'; 2359 return; 2360 } 2361 // Lazy resolve the path to current module. 2362 if (saved_jvm_path[0] != 0) { 2363 strcpy(buf, saved_jvm_path); 2364 return; 2365 } 2366 2367 char dli_fname[MAXPATHLEN]; 2368 bool ret = dll_address_to_library_name( 2369 CAST_FROM_FN_PTR(address, os::jvm_path), 2370 dli_fname, sizeof(dli_fname), NULL); 2371 assert(ret, "cannot locate libjvm"); 2372 char *rp = NULL; 2373 if (ret && dli_fname[0] != '\0') { 2374 rp = os::Posix::realpath(dli_fname, buf, buflen); 2375 } 2376 if (rp == NULL) { 2377 return; 2378 } 2379 2380 if (Arguments::sun_java_launcher_is_altjvm()) { 2381 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2382 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2383 // If "/jre/lib/" appears at the right place in the string, then 2384 // assume we are installed in a JDK and we're done. Otherwise, check 2385 // for a JAVA_HOME environment variable and fix up the path so it 2386 // looks like libjvm.so is installed there (append a fake suffix 2387 // hotspot/libjvm.so). 2388 const char *p = buf + strlen(buf) - 1; 2389 for (int count = 0; p > buf && count < 5; ++count) { 2390 for (--p; p > buf && *p != '/'; --p) 2391 /* empty */ ; 2392 } 2393 2394 if (strncmp(p, "/jre/lib/", 9) != 0) { 2395 // Look for JAVA_HOME in the environment. 2396 char* java_home_var = ::getenv("JAVA_HOME"); 2397 if (java_home_var != NULL && java_home_var[0] != 0) { 2398 char* jrelib_p; 2399 int len; 2400 2401 // Check the current module name "libjvm.so". 2402 p = strrchr(buf, '/'); 2403 if (p == NULL) { 2404 return; 2405 } 2406 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2407 2408 rp = os::Posix::realpath(java_home_var, buf, buflen); 2409 if (rp == NULL) { 2410 return; 2411 } 2412 2413 // determine if this is a legacy image or modules image 2414 // modules image doesn't have "jre" subdirectory 2415 len = strlen(buf); 2416 assert(len < buflen, "Ran out of buffer room"); 2417 jrelib_p = buf + len; 2418 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2419 if (0 != access(buf, F_OK)) { 2420 snprintf(jrelib_p, buflen-len, "/lib"); 2421 } 2422 2423 if (0 == access(buf, F_OK)) { 2424 // Use current module name "libjvm.so" 2425 len = strlen(buf); 2426 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2427 } else { 2428 // Go back to path of .so 2429 rp = os::Posix::realpath(dli_fname, buf, buflen); 2430 if (rp == NULL) { 2431 return; 2432 } 2433 } 2434 } 2435 } 2436 } 2437 2438 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2439 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2440 } 2441 2442 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2443 // no prefix required, not even "_" 2444 } 2445 2446 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2447 // no suffix required 2448 } 2449 2450 //////////////////////////////////////////////////////////////////////////////// 2451 // sun.misc.Signal support 2452 2453 static volatile jint sigint_count = 0; 2454 2455 static void UserHandler(int sig, void *siginfo, void *context) { 2456 // 4511530 - sem_post is serialized and handled by the manager thread. When 2457 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2458 // don't want to flood the manager thread with sem_post requests. 2459 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2460 return; 2461 } 2462 2463 // Ctrl-C is pressed during error reporting, likely because the error 2464 // handler fails to abort. Let VM die immediately. 2465 if (sig == SIGINT && VMError::is_error_reported()) { 2466 os::die(); 2467 } 2468 2469 os::signal_notify(sig); 2470 } 2471 2472 void* os::user_handler() { 2473 return CAST_FROM_FN_PTR(void*, UserHandler); 2474 } 2475 2476 static struct timespec create_semaphore_timespec(unsigned int sec, int nsec) { 2477 struct timespec ts; 2478 // Semaphore's are always associated with CLOCK_REALTIME 2479 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2480 // see os_posix.cpp for discussion on overflow checking 2481 if (sec >= MAX_SECS) { 2482 ts.tv_sec += MAX_SECS; 2483 ts.tv_nsec = 0; 2484 } else { 2485 ts.tv_sec += sec; 2486 ts.tv_nsec += nsec; 2487 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2488 ts.tv_nsec -= NANOSECS_PER_SEC; 2489 ++ts.tv_sec; // note: this must be <= max_secs 2490 } 2491 } 2492 2493 return ts; 2494 } 2495 2496 extern "C" { 2497 typedef void (*sa_handler_t)(int); 2498 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2499 } 2500 2501 void* os::signal(int signal_number, void* handler) { 2502 struct sigaction sigAct, oldSigAct; 2503 2504 sigfillset(&(sigAct.sa_mask)); 2505 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2506 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2507 2508 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2509 // -1 means registration failed 2510 return (void *)-1; 2511 } 2512 2513 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2514 } 2515 2516 void os::signal_raise(int signal_number) { 2517 ::raise(signal_number); 2518 } 2519 2520 // The following code is moved from os.cpp for making this 2521 // code platform specific, which it is by its very nature. 2522 2523 // Will be modified when max signal is changed to be dynamic 2524 int os::sigexitnum_pd() { 2525 return NSIG; 2526 } 2527 2528 // a counter for each possible signal value 2529 static volatile jint pending_signals[NSIG+1] = { 0 }; 2530 2531 // Linux(POSIX) specific hand shaking semaphore. 2532 static Semaphore* sig_sem = NULL; 2533 static PosixSemaphore sr_semaphore; 2534 2535 void os::signal_init_pd() { 2536 // Initialize signal structures 2537 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2538 2539 // Initialize signal semaphore 2540 sig_sem = new Semaphore(); 2541 } 2542 2543 void os::signal_notify(int sig) { 2544 if (sig_sem != NULL) { 2545 Atomic::inc(&pending_signals[sig]); 2546 sig_sem->signal(); 2547 } else { 2548 // Signal thread is not created with ReduceSignalUsage and signal_init_pd 2549 // initialization isn't called. 2550 assert(ReduceSignalUsage, "signal semaphore should be created"); 2551 } 2552 } 2553 2554 static int check_pending_signals() { 2555 Atomic::store(0, &sigint_count); 2556 for (;;) { 2557 for (int i = 0; i < NSIG + 1; i++) { 2558 jint n = pending_signals[i]; 2559 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2560 return i; 2561 } 2562 } 2563 JavaThread *thread = JavaThread::current(); 2564 ThreadBlockInVM tbivm(thread); 2565 2566 bool threadIsSuspended; 2567 do { 2568 thread->set_suspend_equivalent(); 2569 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2570 sig_sem->wait(); 2571 2572 // were we externally suspended while we were waiting? 2573 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2574 if (threadIsSuspended) { 2575 // The semaphore has been incremented, but while we were waiting 2576 // another thread suspended us. We don't want to continue running 2577 // while suspended because that would surprise the thread that 2578 // suspended us. 2579 sig_sem->signal(); 2580 2581 thread->java_suspend_self(); 2582 } 2583 } while (threadIsSuspended); 2584 } 2585 } 2586 2587 int os::signal_wait() { 2588 return check_pending_signals(); 2589 } 2590 2591 //////////////////////////////////////////////////////////////////////////////// 2592 // Virtual Memory 2593 2594 int os::vm_page_size() { 2595 // Seems redundant as all get out 2596 assert(os::Linux::page_size() != -1, "must call os::init"); 2597 return os::Linux::page_size(); 2598 } 2599 2600 // Solaris allocates memory by pages. 2601 int os::vm_allocation_granularity() { 2602 assert(os::Linux::page_size() != -1, "must call os::init"); 2603 return os::Linux::page_size(); 2604 } 2605 2606 // Rationale behind this function: 2607 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2608 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2609 // samples for JITted code. Here we create private executable mapping over the code cache 2610 // and then we can use standard (well, almost, as mapping can change) way to provide 2611 // info for the reporting script by storing timestamp and location of symbol 2612 void linux_wrap_code(char* base, size_t size) { 2613 static volatile jint cnt = 0; 2614 2615 if (!UseOprofile) { 2616 return; 2617 } 2618 2619 char buf[PATH_MAX+1]; 2620 int num = Atomic::add(1, &cnt); 2621 2622 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2623 os::get_temp_directory(), os::current_process_id(), num); 2624 unlink(buf); 2625 2626 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2627 2628 if (fd != -1) { 2629 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2630 if (rv != (off_t)-1) { 2631 if (::write(fd, "", 1) == 1) { 2632 mmap(base, size, 2633 PROT_READ|PROT_WRITE|PROT_EXEC, 2634 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2635 } 2636 } 2637 ::close(fd); 2638 unlink(buf); 2639 } 2640 } 2641 2642 static bool recoverable_mmap_error(int err) { 2643 // See if the error is one we can let the caller handle. This 2644 // list of errno values comes from JBS-6843484. I can't find a 2645 // Linux man page that documents this specific set of errno 2646 // values so while this list currently matches Solaris, it may 2647 // change as we gain experience with this failure mode. 2648 switch (err) { 2649 case EBADF: 2650 case EINVAL: 2651 case ENOTSUP: 2652 // let the caller deal with these errors 2653 return true; 2654 2655 default: 2656 // Any remaining errors on this OS can cause our reserved mapping 2657 // to be lost. That can cause confusion where different data 2658 // structures think they have the same memory mapped. The worst 2659 // scenario is if both the VM and a library think they have the 2660 // same memory mapped. 2661 return false; 2662 } 2663 } 2664 2665 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2666 int err) { 2667 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2668 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2669 os::strerror(err), err); 2670 } 2671 2672 static void warn_fail_commit_memory(char* addr, size_t size, 2673 size_t alignment_hint, bool exec, 2674 int err) { 2675 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2676 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2677 alignment_hint, exec, os::strerror(err), err); 2678 } 2679 2680 // NOTE: Linux kernel does not really reserve the pages for us. 2681 // All it does is to check if there are enough free pages 2682 // left at the time of mmap(). This could be a potential 2683 // problem. 2684 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2685 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2686 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2687 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2688 if (res != (uintptr_t) MAP_FAILED) { 2689 if (UseNUMAInterleaving) { 2690 numa_make_global(addr, size); 2691 } 2692 return 0; 2693 } 2694 2695 int err = errno; // save errno from mmap() call above 2696 2697 if (!recoverable_mmap_error(err)) { 2698 warn_fail_commit_memory(addr, size, exec, err); 2699 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2700 } 2701 2702 return err; 2703 } 2704 2705 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2706 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2707 } 2708 2709 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2710 const char* mesg) { 2711 assert(mesg != NULL, "mesg must be specified"); 2712 int err = os::Linux::commit_memory_impl(addr, size, exec); 2713 if (err != 0) { 2714 // the caller wants all commit errors to exit with the specified mesg: 2715 warn_fail_commit_memory(addr, size, exec, err); 2716 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2717 } 2718 } 2719 2720 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2721 #ifndef MAP_HUGETLB 2722 #define MAP_HUGETLB 0x40000 2723 #endif 2724 2725 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2726 #ifndef MADV_HUGEPAGE 2727 #define MADV_HUGEPAGE 14 2728 #endif 2729 2730 int os::Linux::commit_memory_impl(char* addr, size_t size, 2731 size_t alignment_hint, bool exec) { 2732 int err = os::Linux::commit_memory_impl(addr, size, exec); 2733 if (err == 0) { 2734 realign_memory(addr, size, alignment_hint); 2735 } 2736 return err; 2737 } 2738 2739 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2740 bool exec) { 2741 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2742 } 2743 2744 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2745 size_t alignment_hint, bool exec, 2746 const char* mesg) { 2747 assert(mesg != NULL, "mesg must be specified"); 2748 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2749 if (err != 0) { 2750 // the caller wants all commit errors to exit with the specified mesg: 2751 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2752 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2753 } 2754 } 2755 2756 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2757 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2758 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2759 // be supported or the memory may already be backed by huge pages. 2760 ::madvise(addr, bytes, MADV_HUGEPAGE); 2761 } 2762 } 2763 2764 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2765 // This method works by doing an mmap over an existing mmaping and effectively discarding 2766 // the existing pages. However it won't work for SHM-based large pages that cannot be 2767 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2768 // small pages on top of the SHM segment. This method always works for small pages, so we 2769 // allow that in any case. 2770 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2771 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2772 } 2773 } 2774 2775 void os::numa_make_global(char *addr, size_t bytes) { 2776 Linux::numa_interleave_memory(addr, bytes); 2777 } 2778 2779 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2780 // bind policy to MPOL_PREFERRED for the current thread. 2781 #define USE_MPOL_PREFERRED 0 2782 2783 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2784 // To make NUMA and large pages more robust when both enabled, we need to ease 2785 // the requirements on where the memory should be allocated. MPOL_BIND is the 2786 // default policy and it will force memory to be allocated on the specified 2787 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2788 // the specified node, but will not force it. Using this policy will prevent 2789 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2790 // free large pages. 2791 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2792 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2793 } 2794 2795 bool os::numa_topology_changed() { return false; } 2796 2797 size_t os::numa_get_groups_num() { 2798 // Return just the number of nodes in which it's possible to allocate memory 2799 // (in numa terminology, configured nodes). 2800 return Linux::numa_num_configured_nodes(); 2801 } 2802 2803 int os::numa_get_group_id() { 2804 int cpu_id = Linux::sched_getcpu(); 2805 if (cpu_id != -1) { 2806 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2807 if (lgrp_id != -1) { 2808 return lgrp_id; 2809 } 2810 } 2811 return 0; 2812 } 2813 2814 int os::Linux::get_existing_num_nodes() { 2815 size_t node; 2816 size_t highest_node_number = Linux::numa_max_node(); 2817 int num_nodes = 0; 2818 2819 // Get the total number of nodes in the system including nodes without memory. 2820 for (node = 0; node <= highest_node_number; node++) { 2821 if (isnode_in_existing_nodes(node)) { 2822 num_nodes++; 2823 } 2824 } 2825 return num_nodes; 2826 } 2827 2828 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2829 size_t highest_node_number = Linux::numa_max_node(); 2830 size_t i = 0; 2831 2832 // Map all node ids in which is possible to allocate memory. Also nodes are 2833 // not always consecutively available, i.e. available from 0 to the highest 2834 // node number. 2835 for (size_t node = 0; node <= highest_node_number; node++) { 2836 if (Linux::isnode_in_configured_nodes(node)) { 2837 ids[i++] = node; 2838 } 2839 } 2840 return i; 2841 } 2842 2843 bool os::get_page_info(char *start, page_info* info) { 2844 return false; 2845 } 2846 2847 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2848 page_info* page_found) { 2849 return end; 2850 } 2851 2852 2853 int os::Linux::sched_getcpu_syscall(void) { 2854 unsigned int cpu = 0; 2855 int retval = -1; 2856 2857 #if defined(IA32) 2858 #ifndef SYS_getcpu 2859 #define SYS_getcpu 318 2860 #endif 2861 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2862 #elif defined(AMD64) 2863 // Unfortunately we have to bring all these macros here from vsyscall.h 2864 // to be able to compile on old linuxes. 2865 #define __NR_vgetcpu 2 2866 #define VSYSCALL_START (-10UL << 20) 2867 #define VSYSCALL_SIZE 1024 2868 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2869 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2870 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2871 retval = vgetcpu(&cpu, NULL, NULL); 2872 #endif 2873 2874 return (retval == -1) ? retval : cpu; 2875 } 2876 2877 void os::Linux::sched_getcpu_init() { 2878 // sched_getcpu() should be in libc. 2879 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2880 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2881 2882 // If it's not, try a direct syscall. 2883 if (sched_getcpu() == -1) { 2884 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2885 (void*)&sched_getcpu_syscall)); 2886 } 2887 } 2888 2889 // Something to do with the numa-aware allocator needs these symbols 2890 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2891 extern "C" JNIEXPORT void numa_error(char *where) { } 2892 2893 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 2894 // load symbol from base version instead. 2895 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2896 void *f = dlvsym(handle, name, "libnuma_1.1"); 2897 if (f == NULL) { 2898 f = dlsym(handle, name); 2899 } 2900 return f; 2901 } 2902 2903 // Handle request to load libnuma symbol version 1.2 (API v2) only. 2904 // Return NULL if the symbol is not defined in this particular version. 2905 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 2906 return dlvsym(handle, name, "libnuma_1.2"); 2907 } 2908 2909 bool os::Linux::libnuma_init() { 2910 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 2911 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2912 if (handle != NULL) { 2913 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2914 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2915 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2916 libnuma_dlsym(handle, "numa_max_node"))); 2917 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 2918 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 2919 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2920 libnuma_dlsym(handle, "numa_available"))); 2921 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2922 libnuma_dlsym(handle, "numa_tonode_memory"))); 2923 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2924 libnuma_dlsym(handle, "numa_interleave_memory"))); 2925 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 2926 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 2927 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2928 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2929 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 2930 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 2931 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 2932 libnuma_dlsym(handle, "numa_distance"))); 2933 2934 if (numa_available() != -1) { 2935 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2936 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 2937 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 2938 // Create an index -> node mapping, since nodes are not always consecutive 2939 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2940 rebuild_nindex_to_node_map(); 2941 // Create a cpu -> node mapping 2942 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2943 rebuild_cpu_to_node_map(); 2944 return true; 2945 } 2946 } 2947 } 2948 return false; 2949 } 2950 2951 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 2952 // Creating guard page is very expensive. Java thread has HotSpot 2953 // guard pages, only enable glibc guard page for non-Java threads. 2954 // (Remember: compiler thread is a Java thread, too!) 2955 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 2956 } 2957 2958 void os::Linux::rebuild_nindex_to_node_map() { 2959 int highest_node_number = Linux::numa_max_node(); 2960 2961 nindex_to_node()->clear(); 2962 for (int node = 0; node <= highest_node_number; node++) { 2963 if (Linux::isnode_in_existing_nodes(node)) { 2964 nindex_to_node()->append(node); 2965 } 2966 } 2967 } 2968 2969 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2970 // The table is later used in get_node_by_cpu(). 2971 void os::Linux::rebuild_cpu_to_node_map() { 2972 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2973 // in libnuma (possible values are starting from 16, 2974 // and continuing up with every other power of 2, but less 2975 // than the maximum number of CPUs supported by kernel), and 2976 // is a subject to change (in libnuma version 2 the requirements 2977 // are more reasonable) we'll just hardcode the number they use 2978 // in the library. 2979 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2980 2981 size_t cpu_num = processor_count(); 2982 size_t cpu_map_size = NCPUS / BitsPerCLong; 2983 size_t cpu_map_valid_size = 2984 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2985 2986 cpu_to_node()->clear(); 2987 cpu_to_node()->at_grow(cpu_num - 1); 2988 2989 size_t node_num = get_existing_num_nodes(); 2990 2991 int distance = 0; 2992 int closest_distance = INT_MAX; 2993 int closest_node = 0; 2994 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2995 for (size_t i = 0; i < node_num; i++) { 2996 // Check if node is configured (not a memory-less node). If it is not, find 2997 // the closest configured node. 2998 if (!isnode_in_configured_nodes(nindex_to_node()->at(i))) { 2999 closest_distance = INT_MAX; 3000 // Check distance from all remaining nodes in the system. Ignore distance 3001 // from itself and from another non-configured node. 3002 for (size_t m = 0; m < node_num; m++) { 3003 if (m != i && isnode_in_configured_nodes(nindex_to_node()->at(m))) { 3004 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 3005 // If a closest node is found, update. There is always at least one 3006 // configured node in the system so there is always at least one node 3007 // close. 3008 if (distance != 0 && distance < closest_distance) { 3009 closest_distance = distance; 3010 closest_node = nindex_to_node()->at(m); 3011 } 3012 } 3013 } 3014 } else { 3015 // Current node is already a configured node. 3016 closest_node = nindex_to_node()->at(i); 3017 } 3018 3019 // Get cpus from the original node and map them to the closest node. If node 3020 // is a configured node (not a memory-less node), then original node and 3021 // closest node are the same. 3022 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 3023 for (size_t j = 0; j < cpu_map_valid_size; j++) { 3024 if (cpu_map[j] != 0) { 3025 for (size_t k = 0; k < BitsPerCLong; k++) { 3026 if (cpu_map[j] & (1UL << k)) { 3027 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 3028 } 3029 } 3030 } 3031 } 3032 } 3033 } 3034 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 3035 } 3036 3037 int os::Linux::get_node_by_cpu(int cpu_id) { 3038 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3039 return cpu_to_node()->at(cpu_id); 3040 } 3041 return -1; 3042 } 3043 3044 GrowableArray<int>* os::Linux::_cpu_to_node; 3045 GrowableArray<int>* os::Linux::_nindex_to_node; 3046 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3047 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3048 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3049 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3050 os::Linux::numa_available_func_t os::Linux::_numa_available; 3051 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3052 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3053 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3054 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3055 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3056 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3057 unsigned long* os::Linux::_numa_all_nodes; 3058 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3059 struct bitmask* os::Linux::_numa_nodes_ptr; 3060 3061 bool os::pd_uncommit_memory(char* addr, size_t size) { 3062 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3063 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3064 return res != (uintptr_t) MAP_FAILED; 3065 } 3066 3067 static address get_stack_commited_bottom(address bottom, size_t size) { 3068 address nbot = bottom; 3069 address ntop = bottom + size; 3070 3071 size_t page_sz = os::vm_page_size(); 3072 unsigned pages = size / page_sz; 3073 3074 unsigned char vec[1]; 3075 unsigned imin = 1, imax = pages + 1, imid; 3076 int mincore_return_value = 0; 3077 3078 assert(imin <= imax, "Unexpected page size"); 3079 3080 while (imin < imax) { 3081 imid = (imax + imin) / 2; 3082 nbot = ntop - (imid * page_sz); 3083 3084 // Use a trick with mincore to check whether the page is mapped or not. 3085 // mincore sets vec to 1 if page resides in memory and to 0 if page 3086 // is swapped output but if page we are asking for is unmapped 3087 // it returns -1,ENOMEM 3088 mincore_return_value = mincore(nbot, page_sz, vec); 3089 3090 if (mincore_return_value == -1) { 3091 // Page is not mapped go up 3092 // to find first mapped page 3093 if (errno != EAGAIN) { 3094 assert(errno == ENOMEM, "Unexpected mincore errno"); 3095 imax = imid; 3096 } 3097 } else { 3098 // Page is mapped go down 3099 // to find first not mapped page 3100 imin = imid + 1; 3101 } 3102 } 3103 3104 nbot = nbot + page_sz; 3105 3106 // Adjust stack bottom one page up if last checked page is not mapped 3107 if (mincore_return_value == -1) { 3108 nbot = nbot + page_sz; 3109 } 3110 3111 return nbot; 3112 } 3113 3114 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3115 int mincore_return_value; 3116 const size_t stripe = 1024; // query this many pages each time 3117 unsigned char vec[stripe]; 3118 const size_t page_sz = os::vm_page_size(); 3119 size_t pages = size / page_sz; 3120 3121 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3122 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3123 3124 committed_start = NULL; 3125 3126 int loops = (pages + stripe - 1) / stripe; 3127 int committed_pages = 0; 3128 address loop_base = start; 3129 for (int index = 0; index < loops; index ++) { 3130 assert(pages > 0, "Nothing to do"); 3131 int pages_to_query = (pages >= stripe) ? stripe : pages; 3132 pages -= pages_to_query; 3133 3134 // Get stable read 3135 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3136 3137 // During shutdown, some memory goes away without properly notifying NMT, 3138 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3139 // Bailout and return as not committed for now. 3140 if (mincore_return_value == -1 && errno == ENOMEM) { 3141 return false; 3142 } 3143 3144 assert(mincore_return_value == 0, "Range must be valid"); 3145 // Process this stripe 3146 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3147 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3148 // End of current contiguous region 3149 if (committed_start != NULL) { 3150 break; 3151 } 3152 } else { // committed 3153 // Start of region 3154 if (committed_start == NULL) { 3155 committed_start = loop_base + page_sz * vecIdx; 3156 } 3157 committed_pages ++; 3158 } 3159 } 3160 3161 loop_base += pages_to_query * page_sz; 3162 } 3163 3164 if (committed_start != NULL) { 3165 assert(committed_pages > 0, "Must have committed region"); 3166 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3167 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3168 committed_size = page_sz * committed_pages; 3169 return true; 3170 } else { 3171 assert(committed_pages == 0, "Should not have committed region"); 3172 return false; 3173 } 3174 } 3175 3176 3177 // Linux uses a growable mapping for the stack, and if the mapping for 3178 // the stack guard pages is not removed when we detach a thread the 3179 // stack cannot grow beyond the pages where the stack guard was 3180 // mapped. If at some point later in the process the stack expands to 3181 // that point, the Linux kernel cannot expand the stack any further 3182 // because the guard pages are in the way, and a segfault occurs. 3183 // 3184 // However, it's essential not to split the stack region by unmapping 3185 // a region (leaving a hole) that's already part of the stack mapping, 3186 // so if the stack mapping has already grown beyond the guard pages at 3187 // the time we create them, we have to truncate the stack mapping. 3188 // So, we need to know the extent of the stack mapping when 3189 // create_stack_guard_pages() is called. 3190 3191 // We only need this for stacks that are growable: at the time of 3192 // writing thread stacks don't use growable mappings (i.e. those 3193 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3194 // only applies to the main thread. 3195 3196 // If the (growable) stack mapping already extends beyond the point 3197 // where we're going to put our guard pages, truncate the mapping at 3198 // that point by munmap()ping it. This ensures that when we later 3199 // munmap() the guard pages we don't leave a hole in the stack 3200 // mapping. This only affects the main/primordial thread 3201 3202 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3203 if (os::is_primordial_thread()) { 3204 // As we manually grow stack up to bottom inside create_attached_thread(), 3205 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3206 // we don't need to do anything special. 3207 // Check it first, before calling heavy function. 3208 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3209 unsigned char vec[1]; 3210 3211 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3212 // Fallback to slow path on all errors, including EAGAIN 3213 stack_extent = (uintptr_t) get_stack_commited_bottom( 3214 os::Linux::initial_thread_stack_bottom(), 3215 (size_t)addr - stack_extent); 3216 } 3217 3218 if (stack_extent < (uintptr_t)addr) { 3219 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3220 } 3221 } 3222 3223 return os::commit_memory(addr, size, !ExecMem); 3224 } 3225 3226 // If this is a growable mapping, remove the guard pages entirely by 3227 // munmap()ping them. If not, just call uncommit_memory(). This only 3228 // affects the main/primordial thread, but guard against future OS changes. 3229 // It's safe to always unmap guard pages for primordial thread because we 3230 // always place it right after end of the mapped region. 3231 3232 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3233 uintptr_t stack_extent, stack_base; 3234 3235 if (os::is_primordial_thread()) { 3236 return ::munmap(addr, size) == 0; 3237 } 3238 3239 return os::uncommit_memory(addr, size); 3240 } 3241 3242 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3243 // at 'requested_addr'. If there are existing memory mappings at the same 3244 // location, however, they will be overwritten. If 'fixed' is false, 3245 // 'requested_addr' is only treated as a hint, the return value may or 3246 // may not start from the requested address. Unlike Linux mmap(), this 3247 // function returns NULL to indicate failure. 3248 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3249 char * addr; 3250 int flags; 3251 3252 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3253 if (fixed) { 3254 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3255 flags |= MAP_FIXED; 3256 } 3257 3258 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3259 // touch an uncommitted page. Otherwise, the read/write might 3260 // succeed if we have enough swap space to back the physical page. 3261 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3262 flags, -1, 0); 3263 3264 return addr == MAP_FAILED ? NULL : addr; 3265 } 3266 3267 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3268 // (req_addr != NULL) or with a given alignment. 3269 // - bytes shall be a multiple of alignment. 3270 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3271 // - alignment sets the alignment at which memory shall be allocated. 3272 // It must be a multiple of allocation granularity. 3273 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3274 // req_addr or NULL. 3275 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3276 3277 size_t extra_size = bytes; 3278 if (req_addr == NULL && alignment > 0) { 3279 extra_size += alignment; 3280 } 3281 3282 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3283 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3284 -1, 0); 3285 if (start == MAP_FAILED) { 3286 start = NULL; 3287 } else { 3288 if (req_addr != NULL) { 3289 if (start != req_addr) { 3290 ::munmap(start, extra_size); 3291 start = NULL; 3292 } 3293 } else { 3294 char* const start_aligned = align_up(start, alignment); 3295 char* const end_aligned = start_aligned + bytes; 3296 char* const end = start + extra_size; 3297 if (start_aligned > start) { 3298 ::munmap(start, start_aligned - start); 3299 } 3300 if (end_aligned < end) { 3301 ::munmap(end_aligned, end - end_aligned); 3302 } 3303 start = start_aligned; 3304 } 3305 } 3306 return start; 3307 } 3308 3309 static int anon_munmap(char * addr, size_t size) { 3310 return ::munmap(addr, size) == 0; 3311 } 3312 3313 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3314 size_t alignment_hint) { 3315 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3316 } 3317 3318 bool os::pd_release_memory(char* addr, size_t size) { 3319 return anon_munmap(addr, size); 3320 } 3321 3322 static bool linux_mprotect(char* addr, size_t size, int prot) { 3323 // Linux wants the mprotect address argument to be page aligned. 3324 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3325 3326 // According to SUSv3, mprotect() should only be used with mappings 3327 // established by mmap(), and mmap() always maps whole pages. Unaligned 3328 // 'addr' likely indicates problem in the VM (e.g. trying to change 3329 // protection of malloc'ed or statically allocated memory). Check the 3330 // caller if you hit this assert. 3331 assert(addr == bottom, "sanity check"); 3332 3333 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3334 return ::mprotect(bottom, size, prot) == 0; 3335 } 3336 3337 // Set protections specified 3338 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3339 bool is_committed) { 3340 unsigned int p = 0; 3341 switch (prot) { 3342 case MEM_PROT_NONE: p = PROT_NONE; break; 3343 case MEM_PROT_READ: p = PROT_READ; break; 3344 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3345 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3346 default: 3347 ShouldNotReachHere(); 3348 } 3349 // is_committed is unused. 3350 return linux_mprotect(addr, bytes, p); 3351 } 3352 3353 bool os::guard_memory(char* addr, size_t size) { 3354 return linux_mprotect(addr, size, PROT_NONE); 3355 } 3356 3357 bool os::unguard_memory(char* addr, size_t size) { 3358 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3359 } 3360 3361 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3362 size_t page_size) { 3363 bool result = false; 3364 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3365 MAP_ANONYMOUS|MAP_PRIVATE, 3366 -1, 0); 3367 if (p != MAP_FAILED) { 3368 void *aligned_p = align_up(p, page_size); 3369 3370 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3371 3372 munmap(p, page_size * 2); 3373 } 3374 3375 if (warn && !result) { 3376 warning("TransparentHugePages is not supported by the operating system."); 3377 } 3378 3379 return result; 3380 } 3381 3382 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3383 bool result = false; 3384 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3385 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3386 -1, 0); 3387 3388 if (p != MAP_FAILED) { 3389 // We don't know if this really is a huge page or not. 3390 FILE *fp = fopen("/proc/self/maps", "r"); 3391 if (fp) { 3392 while (!feof(fp)) { 3393 char chars[257]; 3394 long x = 0; 3395 if (fgets(chars, sizeof(chars), fp)) { 3396 if (sscanf(chars, "%lx-%*x", &x) == 1 3397 && x == (long)p) { 3398 if (strstr (chars, "hugepage")) { 3399 result = true; 3400 break; 3401 } 3402 } 3403 } 3404 } 3405 fclose(fp); 3406 } 3407 munmap(p, page_size); 3408 } 3409 3410 if (warn && !result) { 3411 warning("HugeTLBFS is not supported by the operating system."); 3412 } 3413 3414 return result; 3415 } 3416 3417 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3418 // 3419 // From the coredump_filter documentation: 3420 // 3421 // - (bit 0) anonymous private memory 3422 // - (bit 1) anonymous shared memory 3423 // - (bit 2) file-backed private memory 3424 // - (bit 3) file-backed shared memory 3425 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3426 // effective only if the bit 2 is cleared) 3427 // - (bit 5) hugetlb private memory 3428 // - (bit 6) hugetlb shared memory 3429 // - (bit 7) dax private memory 3430 // - (bit 8) dax shared memory 3431 // 3432 static void set_coredump_filter(bool largepages, bool dax_shared) { 3433 FILE *f; 3434 long cdm; 3435 bool filter_changed = false; 3436 3437 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3438 return; 3439 } 3440 3441 if (fscanf(f, "%lx", &cdm) != 1) { 3442 fclose(f); 3443 return; 3444 } 3445 3446 rewind(f); 3447 3448 if (largepages && (cdm & LARGEPAGES_BIT) == 0) { 3449 cdm |= LARGEPAGES_BIT; 3450 filter_changed = true; 3451 } 3452 if (dax_shared && (cdm & DAX_SHARED_BIT) == 0) { 3453 cdm |= DAX_SHARED_BIT; 3454 filter_changed = true; 3455 } 3456 if (filter_changed) { 3457 fprintf(f, "%#lx", cdm); 3458 } 3459 3460 fclose(f); 3461 } 3462 3463 // Large page support 3464 3465 static size_t _large_page_size = 0; 3466 3467 size_t os::Linux::find_large_page_size() { 3468 size_t large_page_size = 0; 3469 3470 // large_page_size on Linux is used to round up heap size. x86 uses either 3471 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3472 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3473 // page as large as 256M. 3474 // 3475 // Here we try to figure out page size by parsing /proc/meminfo and looking 3476 // for a line with the following format: 3477 // Hugepagesize: 2048 kB 3478 // 3479 // If we can't determine the value (e.g. /proc is not mounted, or the text 3480 // format has been changed), we'll use the largest page size supported by 3481 // the processor. 3482 3483 #ifndef ZERO 3484 large_page_size = 3485 AARCH64_ONLY(2 * M) 3486 AMD64_ONLY(2 * M) 3487 ARM32_ONLY(2 * M) 3488 IA32_ONLY(4 * M) 3489 IA64_ONLY(256 * M) 3490 PPC_ONLY(4 * M) 3491 S390_ONLY(1 * M) 3492 SPARC_ONLY(4 * M); 3493 #endif // ZERO 3494 3495 FILE *fp = fopen("/proc/meminfo", "r"); 3496 if (fp) { 3497 while (!feof(fp)) { 3498 int x = 0; 3499 char buf[16]; 3500 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3501 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3502 large_page_size = x * K; 3503 break; 3504 } 3505 } else { 3506 // skip to next line 3507 for (;;) { 3508 int ch = fgetc(fp); 3509 if (ch == EOF || ch == (int)'\n') break; 3510 } 3511 } 3512 } 3513 fclose(fp); 3514 } 3515 3516 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3517 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3518 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3519 proper_unit_for_byte_size(large_page_size)); 3520 } 3521 3522 return large_page_size; 3523 } 3524 3525 size_t os::Linux::setup_large_page_size() { 3526 _large_page_size = Linux::find_large_page_size(); 3527 const size_t default_page_size = (size_t)Linux::page_size(); 3528 if (_large_page_size > default_page_size) { 3529 _page_sizes[0] = _large_page_size; 3530 _page_sizes[1] = default_page_size; 3531 _page_sizes[2] = 0; 3532 } 3533 3534 return _large_page_size; 3535 } 3536 3537 bool os::Linux::setup_large_page_type(size_t page_size) { 3538 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3539 FLAG_IS_DEFAULT(UseSHM) && 3540 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3541 3542 // The type of large pages has not been specified by the user. 3543 3544 // Try UseHugeTLBFS and then UseSHM. 3545 UseHugeTLBFS = UseSHM = true; 3546 3547 // Don't try UseTransparentHugePages since there are known 3548 // performance issues with it turned on. This might change in the future. 3549 UseTransparentHugePages = false; 3550 } 3551 3552 if (UseTransparentHugePages) { 3553 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3554 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3555 UseHugeTLBFS = false; 3556 UseSHM = false; 3557 return true; 3558 } 3559 UseTransparentHugePages = false; 3560 } 3561 3562 if (UseHugeTLBFS) { 3563 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3564 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3565 UseSHM = false; 3566 return true; 3567 } 3568 UseHugeTLBFS = false; 3569 } 3570 3571 return UseSHM; 3572 } 3573 3574 void os::large_page_init() { 3575 if (!UseLargePages && 3576 !UseTransparentHugePages && 3577 !UseHugeTLBFS && 3578 !UseSHM) { 3579 // Not using large pages. 3580 return; 3581 } 3582 3583 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3584 // The user explicitly turned off large pages. 3585 // Ignore the rest of the large pages flags. 3586 UseTransparentHugePages = false; 3587 UseHugeTLBFS = false; 3588 UseSHM = false; 3589 return; 3590 } 3591 3592 size_t large_page_size = Linux::setup_large_page_size(); 3593 UseLargePages = Linux::setup_large_page_type(large_page_size); 3594 3595 set_coredump_filter(true /*largepages*/, false /*dax_shared*/); 3596 } 3597 3598 #ifndef SHM_HUGETLB 3599 #define SHM_HUGETLB 04000 3600 #endif 3601 3602 #define shm_warning_format(format, ...) \ 3603 do { \ 3604 if (UseLargePages && \ 3605 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3606 !FLAG_IS_DEFAULT(UseSHM) || \ 3607 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3608 warning(format, __VA_ARGS__); \ 3609 } \ 3610 } while (0) 3611 3612 #define shm_warning(str) shm_warning_format("%s", str) 3613 3614 #define shm_warning_with_errno(str) \ 3615 do { \ 3616 int err = errno; \ 3617 shm_warning_format(str " (error = %d)", err); \ 3618 } while (0) 3619 3620 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3621 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3622 3623 if (!is_aligned(alignment, SHMLBA)) { 3624 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3625 return NULL; 3626 } 3627 3628 // To ensure that we get 'alignment' aligned memory from shmat, 3629 // we pre-reserve aligned virtual memory and then attach to that. 3630 3631 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3632 if (pre_reserved_addr == NULL) { 3633 // Couldn't pre-reserve aligned memory. 3634 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3635 return NULL; 3636 } 3637 3638 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3639 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3640 3641 if ((intptr_t)addr == -1) { 3642 int err = errno; 3643 shm_warning_with_errno("Failed to attach shared memory."); 3644 3645 assert(err != EACCES, "Unexpected error"); 3646 assert(err != EIDRM, "Unexpected error"); 3647 assert(err != EINVAL, "Unexpected error"); 3648 3649 // Since we don't know if the kernel unmapped the pre-reserved memory area 3650 // we can't unmap it, since that would potentially unmap memory that was 3651 // mapped from other threads. 3652 return NULL; 3653 } 3654 3655 return addr; 3656 } 3657 3658 static char* shmat_at_address(int shmid, char* req_addr) { 3659 if (!is_aligned(req_addr, SHMLBA)) { 3660 assert(false, "Requested address needs to be SHMLBA aligned"); 3661 return NULL; 3662 } 3663 3664 char* addr = (char*)shmat(shmid, req_addr, 0); 3665 3666 if ((intptr_t)addr == -1) { 3667 shm_warning_with_errno("Failed to attach shared memory."); 3668 return NULL; 3669 } 3670 3671 return addr; 3672 } 3673 3674 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3675 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3676 if (req_addr != NULL) { 3677 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3678 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3679 return shmat_at_address(shmid, req_addr); 3680 } 3681 3682 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3683 // return large page size aligned memory addresses when req_addr == NULL. 3684 // However, if the alignment is larger than the large page size, we have 3685 // to manually ensure that the memory returned is 'alignment' aligned. 3686 if (alignment > os::large_page_size()) { 3687 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3688 return shmat_with_alignment(shmid, bytes, alignment); 3689 } else { 3690 return shmat_at_address(shmid, NULL); 3691 } 3692 } 3693 3694 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3695 char* req_addr, bool exec) { 3696 // "exec" is passed in but not used. Creating the shared image for 3697 // the code cache doesn't have an SHM_X executable permission to check. 3698 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3699 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3700 assert(is_aligned(req_addr, alignment), "Unaligned address"); 3701 3702 if (!is_aligned(bytes, os::large_page_size())) { 3703 return NULL; // Fallback to small pages. 3704 } 3705 3706 // Create a large shared memory region to attach to based on size. 3707 // Currently, size is the total size of the heap. 3708 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3709 if (shmid == -1) { 3710 // Possible reasons for shmget failure: 3711 // 1. shmmax is too small for Java heap. 3712 // > check shmmax value: cat /proc/sys/kernel/shmmax 3713 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3714 // 2. not enough large page memory. 3715 // > check available large pages: cat /proc/meminfo 3716 // > increase amount of large pages: 3717 // echo new_value > /proc/sys/vm/nr_hugepages 3718 // Note 1: different Linux may use different name for this property, 3719 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3720 // Note 2: it's possible there's enough physical memory available but 3721 // they are so fragmented after a long run that they can't 3722 // coalesce into large pages. Try to reserve large pages when 3723 // the system is still "fresh". 3724 shm_warning_with_errno("Failed to reserve shared memory."); 3725 return NULL; 3726 } 3727 3728 // Attach to the region. 3729 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3730 3731 // Remove shmid. If shmat() is successful, the actual shared memory segment 3732 // will be deleted when it's detached by shmdt() or when the process 3733 // terminates. If shmat() is not successful this will remove the shared 3734 // segment immediately. 3735 shmctl(shmid, IPC_RMID, NULL); 3736 3737 return addr; 3738 } 3739 3740 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3741 int error) { 3742 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3743 3744 bool warn_on_failure = UseLargePages && 3745 (!FLAG_IS_DEFAULT(UseLargePages) || 3746 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3747 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3748 3749 if (warn_on_failure) { 3750 char msg[128]; 3751 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3752 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3753 warning("%s", msg); 3754 } 3755 } 3756 3757 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3758 char* req_addr, 3759 bool exec) { 3760 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3761 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 3762 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3763 3764 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3765 char* addr = (char*)::mmap(req_addr, bytes, prot, 3766 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3767 -1, 0); 3768 3769 if (addr == MAP_FAILED) { 3770 warn_on_large_pages_failure(req_addr, bytes, errno); 3771 return NULL; 3772 } 3773 3774 assert(is_aligned(addr, os::large_page_size()), "Must be"); 3775 3776 return addr; 3777 } 3778 3779 // Reserve memory using mmap(MAP_HUGETLB). 3780 // - bytes shall be a multiple of alignment. 3781 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3782 // - alignment sets the alignment at which memory shall be allocated. 3783 // It must be a multiple of allocation granularity. 3784 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3785 // req_addr or NULL. 3786 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3787 size_t alignment, 3788 char* req_addr, 3789 bool exec) { 3790 size_t large_page_size = os::large_page_size(); 3791 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3792 3793 assert(is_aligned(req_addr, alignment), "Must be"); 3794 assert(is_aligned(bytes, alignment), "Must be"); 3795 3796 // First reserve - but not commit - the address range in small pages. 3797 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3798 3799 if (start == NULL) { 3800 return NULL; 3801 } 3802 3803 assert(is_aligned(start, alignment), "Must be"); 3804 3805 char* end = start + bytes; 3806 3807 // Find the regions of the allocated chunk that can be promoted to large pages. 3808 char* lp_start = align_up(start, large_page_size); 3809 char* lp_end = align_down(end, large_page_size); 3810 3811 size_t lp_bytes = lp_end - lp_start; 3812 3813 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 3814 3815 if (lp_bytes == 0) { 3816 // The mapped region doesn't even span the start and the end of a large page. 3817 // Fall back to allocate a non-special area. 3818 ::munmap(start, end - start); 3819 return NULL; 3820 } 3821 3822 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3823 3824 void* result; 3825 3826 // Commit small-paged leading area. 3827 if (start != lp_start) { 3828 result = ::mmap(start, lp_start - start, prot, 3829 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3830 -1, 0); 3831 if (result == MAP_FAILED) { 3832 ::munmap(lp_start, end - lp_start); 3833 return NULL; 3834 } 3835 } 3836 3837 // Commit large-paged area. 3838 result = ::mmap(lp_start, lp_bytes, prot, 3839 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3840 -1, 0); 3841 if (result == MAP_FAILED) { 3842 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3843 // If the mmap above fails, the large pages region will be unmapped and we 3844 // have regions before and after with small pages. Release these regions. 3845 // 3846 // | mapped | unmapped | mapped | 3847 // ^ ^ ^ ^ 3848 // start lp_start lp_end end 3849 // 3850 ::munmap(start, lp_start - start); 3851 ::munmap(lp_end, end - lp_end); 3852 return NULL; 3853 } 3854 3855 // Commit small-paged trailing area. 3856 if (lp_end != end) { 3857 result = ::mmap(lp_end, end - lp_end, prot, 3858 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3859 -1, 0); 3860 if (result == MAP_FAILED) { 3861 ::munmap(start, lp_end - start); 3862 return NULL; 3863 } 3864 } 3865 3866 return start; 3867 } 3868 3869 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3870 size_t alignment, 3871 char* req_addr, 3872 bool exec) { 3873 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3874 assert(is_aligned(req_addr, alignment), "Must be"); 3875 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3876 assert(is_power_of_2(os::large_page_size()), "Must be"); 3877 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3878 3879 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3880 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3881 } else { 3882 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3883 } 3884 } 3885 3886 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3887 char* req_addr, bool exec) { 3888 assert(UseLargePages, "only for large pages"); 3889 3890 char* addr; 3891 if (UseSHM) { 3892 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3893 } else { 3894 assert(UseHugeTLBFS, "must be"); 3895 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3896 } 3897 3898 if (addr != NULL) { 3899 if (UseNUMAInterleaving) { 3900 numa_make_global(addr, bytes); 3901 } 3902 3903 // The memory is committed 3904 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3905 } 3906 3907 return addr; 3908 } 3909 3910 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3911 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3912 return shmdt(base) == 0; 3913 } 3914 3915 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3916 return pd_release_memory(base, bytes); 3917 } 3918 3919 bool os::release_memory_special(char* base, size_t bytes) { 3920 bool res; 3921 if (MemTracker::tracking_level() > NMT_minimal) { 3922 Tracker tkr(Tracker::release); 3923 res = os::Linux::release_memory_special_impl(base, bytes); 3924 if (res) { 3925 tkr.record((address)base, bytes); 3926 } 3927 3928 } else { 3929 res = os::Linux::release_memory_special_impl(base, bytes); 3930 } 3931 return res; 3932 } 3933 3934 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3935 assert(UseLargePages, "only for large pages"); 3936 bool res; 3937 3938 if (UseSHM) { 3939 res = os::Linux::release_memory_special_shm(base, bytes); 3940 } else { 3941 assert(UseHugeTLBFS, "must be"); 3942 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3943 } 3944 return res; 3945 } 3946 3947 size_t os::large_page_size() { 3948 return _large_page_size; 3949 } 3950 3951 // With SysV SHM the entire memory region must be allocated as shared 3952 // memory. 3953 // HugeTLBFS allows application to commit large page memory on demand. 3954 // However, when committing memory with HugeTLBFS fails, the region 3955 // that was supposed to be committed will lose the old reservation 3956 // and allow other threads to steal that memory region. Because of this 3957 // behavior we can't commit HugeTLBFS memory. 3958 bool os::can_commit_large_page_memory() { 3959 return UseTransparentHugePages; 3960 } 3961 3962 bool os::can_execute_large_page_memory() { 3963 return UseTransparentHugePages || UseHugeTLBFS; 3964 } 3965 3966 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 3967 assert(file_desc >= 0, "file_desc is not valid"); 3968 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 3969 if (result != NULL) { 3970 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 3971 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 3972 } 3973 } 3974 return result; 3975 } 3976 3977 // Reserve memory at an arbitrary address, only if that area is 3978 // available (and not reserved for something else). 3979 3980 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3981 const int max_tries = 10; 3982 char* base[max_tries]; 3983 size_t size[max_tries]; 3984 const size_t gap = 0x000000; 3985 3986 // Assert only that the size is a multiple of the page size, since 3987 // that's all that mmap requires, and since that's all we really know 3988 // about at this low abstraction level. If we need higher alignment, 3989 // we can either pass an alignment to this method or verify alignment 3990 // in one of the methods further up the call chain. See bug 5044738. 3991 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3992 3993 // Repeatedly allocate blocks until the block is allocated at the 3994 // right spot. 3995 3996 // Linux mmap allows caller to pass an address as hint; give it a try first, 3997 // if kernel honors the hint then we can return immediately. 3998 char * addr = anon_mmap(requested_addr, bytes, false); 3999 if (addr == requested_addr) { 4000 return requested_addr; 4001 } 4002 4003 if (addr != NULL) { 4004 // mmap() is successful but it fails to reserve at the requested address 4005 anon_munmap(addr, bytes); 4006 } 4007 4008 int i; 4009 for (i = 0; i < max_tries; ++i) { 4010 base[i] = reserve_memory(bytes); 4011 4012 if (base[i] != NULL) { 4013 // Is this the block we wanted? 4014 if (base[i] == requested_addr) { 4015 size[i] = bytes; 4016 break; 4017 } 4018 4019 // Does this overlap the block we wanted? Give back the overlapped 4020 // parts and try again. 4021 4022 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 4023 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 4024 unmap_memory(base[i], top_overlap); 4025 base[i] += top_overlap; 4026 size[i] = bytes - top_overlap; 4027 } else { 4028 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 4029 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 4030 unmap_memory(requested_addr, bottom_overlap); 4031 size[i] = bytes - bottom_overlap; 4032 } else { 4033 size[i] = bytes; 4034 } 4035 } 4036 } 4037 } 4038 4039 // Give back the unused reserved pieces. 4040 4041 for (int j = 0; j < i; ++j) { 4042 if (base[j] != NULL) { 4043 unmap_memory(base[j], size[j]); 4044 } 4045 } 4046 4047 if (i < max_tries) { 4048 return requested_addr; 4049 } else { 4050 return NULL; 4051 } 4052 } 4053 4054 size_t os::read(int fd, void *buf, unsigned int nBytes) { 4055 return ::read(fd, buf, nBytes); 4056 } 4057 4058 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 4059 return ::pread(fd, buf, nBytes, offset); 4060 } 4061 4062 // Short sleep, direct OS call. 4063 // 4064 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 4065 // sched_yield(2) will actually give up the CPU: 4066 // 4067 // * Alone on this pariticular CPU, keeps running. 4068 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 4069 // (pre 2.6.39). 4070 // 4071 // So calling this with 0 is an alternative. 4072 // 4073 void os::naked_short_sleep(jlong ms) { 4074 struct timespec req; 4075 4076 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 4077 req.tv_sec = 0; 4078 if (ms > 0) { 4079 req.tv_nsec = (ms % 1000) * 1000000; 4080 } else { 4081 req.tv_nsec = 1; 4082 } 4083 4084 nanosleep(&req, NULL); 4085 4086 return; 4087 } 4088 4089 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4090 void os::infinite_sleep() { 4091 while (true) { // sleep forever ... 4092 ::sleep(100); // ... 100 seconds at a time 4093 } 4094 } 4095 4096 // Used to convert frequent JVM_Yield() to nops 4097 bool os::dont_yield() { 4098 return DontYieldALot; 4099 } 4100 4101 void os::naked_yield() { 4102 sched_yield(); 4103 } 4104 4105 //////////////////////////////////////////////////////////////////////////////// 4106 // thread priority support 4107 4108 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4109 // only supports dynamic priority, static priority must be zero. For real-time 4110 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4111 // However, for large multi-threaded applications, SCHED_RR is not only slower 4112 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4113 // of 5 runs - Sep 2005). 4114 // 4115 // The following code actually changes the niceness of kernel-thread/LWP. It 4116 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4117 // not the entire user process, and user level threads are 1:1 mapped to kernel 4118 // threads. It has always been the case, but could change in the future. For 4119 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4120 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 4121 4122 int os::java_to_os_priority[CriticalPriority + 1] = { 4123 19, // 0 Entry should never be used 4124 4125 4, // 1 MinPriority 4126 3, // 2 4127 2, // 3 4128 4129 1, // 4 4130 0, // 5 NormPriority 4131 -1, // 6 4132 4133 -2, // 7 4134 -3, // 8 4135 -4, // 9 NearMaxPriority 4136 4137 -5, // 10 MaxPriority 4138 4139 -5 // 11 CriticalPriority 4140 }; 4141 4142 static int prio_init() { 4143 if (ThreadPriorityPolicy == 1) { 4144 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 4145 // if effective uid is not root. Perhaps, a more elegant way of doing 4146 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 4147 if (geteuid() != 0) { 4148 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 4149 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 4150 } 4151 ThreadPriorityPolicy = 0; 4152 } 4153 } 4154 if (UseCriticalJavaThreadPriority) { 4155 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4156 } 4157 return 0; 4158 } 4159 4160 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4161 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4162 4163 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4164 return (ret == 0) ? OS_OK : OS_ERR; 4165 } 4166 4167 OSReturn os::get_native_priority(const Thread* const thread, 4168 int *priority_ptr) { 4169 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4170 *priority_ptr = java_to_os_priority[NormPriority]; 4171 return OS_OK; 4172 } 4173 4174 errno = 0; 4175 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4176 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4177 } 4178 4179 // Hint to the underlying OS that a task switch would not be good. 4180 // Void return because it's a hint and can fail. 4181 void os::hint_no_preempt() {} 4182 4183 //////////////////////////////////////////////////////////////////////////////// 4184 // suspend/resume support 4185 4186 // The low-level signal-based suspend/resume support is a remnant from the 4187 // old VM-suspension that used to be for java-suspension, safepoints etc, 4188 // within hotspot. Currently used by JFR's OSThreadSampler 4189 // 4190 // The remaining code is greatly simplified from the more general suspension 4191 // code that used to be used. 4192 // 4193 // The protocol is quite simple: 4194 // - suspend: 4195 // - sends a signal to the target thread 4196 // - polls the suspend state of the osthread using a yield loop 4197 // - target thread signal handler (SR_handler) sets suspend state 4198 // and blocks in sigsuspend until continued 4199 // - resume: 4200 // - sets target osthread state to continue 4201 // - sends signal to end the sigsuspend loop in the SR_handler 4202 // 4203 // Note that the SR_lock plays no role in this suspend/resume protocol, 4204 // but is checked for NULL in SR_handler as a thread termination indicator. 4205 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4206 // 4207 // Note that resume_clear_context() and suspend_save_context() are needed 4208 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4209 // which in part is used by: 4210 // - Forte Analyzer: AsyncGetCallTrace() 4211 // - StackBanging: get_frame_at_stack_banging_point() 4212 4213 static void resume_clear_context(OSThread *osthread) { 4214 osthread->set_ucontext(NULL); 4215 osthread->set_siginfo(NULL); 4216 } 4217 4218 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4219 ucontext_t* context) { 4220 osthread->set_ucontext(context); 4221 osthread->set_siginfo(siginfo); 4222 } 4223 4224 // Handler function invoked when a thread's execution is suspended or 4225 // resumed. We have to be careful that only async-safe functions are 4226 // called here (Note: most pthread functions are not async safe and 4227 // should be avoided.) 4228 // 4229 // Note: sigwait() is a more natural fit than sigsuspend() from an 4230 // interface point of view, but sigwait() prevents the signal hander 4231 // from being run. libpthread would get very confused by not having 4232 // its signal handlers run and prevents sigwait()'s use with the 4233 // mutex granting granting signal. 4234 // 4235 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4236 // 4237 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4238 // Save and restore errno to avoid confusing native code with EINTR 4239 // after sigsuspend. 4240 int old_errno = errno; 4241 4242 Thread* thread = Thread::current_or_null_safe(); 4243 assert(thread != NULL, "Missing current thread in SR_handler"); 4244 4245 // On some systems we have seen signal delivery get "stuck" until the signal 4246 // mask is changed as part of thread termination. Check that the current thread 4247 // has not already terminated (via SR_lock()) - else the following assertion 4248 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4249 // destructor has completed. 4250 4251 if (thread->SR_lock() == NULL) { 4252 return; 4253 } 4254 4255 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4256 4257 OSThread* osthread = thread->osthread(); 4258 4259 os::SuspendResume::State current = osthread->sr.state(); 4260 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4261 suspend_save_context(osthread, siginfo, context); 4262 4263 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4264 os::SuspendResume::State state = osthread->sr.suspended(); 4265 if (state == os::SuspendResume::SR_SUSPENDED) { 4266 sigset_t suspend_set; // signals for sigsuspend() 4267 sigemptyset(&suspend_set); 4268 // get current set of blocked signals and unblock resume signal 4269 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4270 sigdelset(&suspend_set, SR_signum); 4271 4272 sr_semaphore.signal(); 4273 // wait here until we are resumed 4274 while (1) { 4275 sigsuspend(&suspend_set); 4276 4277 os::SuspendResume::State result = osthread->sr.running(); 4278 if (result == os::SuspendResume::SR_RUNNING) { 4279 sr_semaphore.signal(); 4280 break; 4281 } 4282 } 4283 4284 } else if (state == os::SuspendResume::SR_RUNNING) { 4285 // request was cancelled, continue 4286 } else { 4287 ShouldNotReachHere(); 4288 } 4289 4290 resume_clear_context(osthread); 4291 } else if (current == os::SuspendResume::SR_RUNNING) { 4292 // request was cancelled, continue 4293 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4294 // ignore 4295 } else { 4296 // ignore 4297 } 4298 4299 errno = old_errno; 4300 } 4301 4302 static int SR_initialize() { 4303 struct sigaction act; 4304 char *s; 4305 4306 // Get signal number to use for suspend/resume 4307 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4308 int sig = ::strtol(s, 0, 10); 4309 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4310 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4311 SR_signum = sig; 4312 } else { 4313 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4314 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4315 } 4316 } 4317 4318 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4319 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4320 4321 sigemptyset(&SR_sigset); 4322 sigaddset(&SR_sigset, SR_signum); 4323 4324 // Set up signal handler for suspend/resume 4325 act.sa_flags = SA_RESTART|SA_SIGINFO; 4326 act.sa_handler = (void (*)(int)) SR_handler; 4327 4328 // SR_signum is blocked by default. 4329 // 4528190 - We also need to block pthread restart signal (32 on all 4330 // supported Linux platforms). Note that LinuxThreads need to block 4331 // this signal for all threads to work properly. So we don't have 4332 // to use hard-coded signal number when setting up the mask. 4333 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4334 4335 if (sigaction(SR_signum, &act, 0) == -1) { 4336 return -1; 4337 } 4338 4339 // Save signal flag 4340 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4341 return 0; 4342 } 4343 4344 static int sr_notify(OSThread* osthread) { 4345 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4346 assert_status(status == 0, status, "pthread_kill"); 4347 return status; 4348 } 4349 4350 // "Randomly" selected value for how long we want to spin 4351 // before bailing out on suspending a thread, also how often 4352 // we send a signal to a thread we want to resume 4353 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4354 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4355 4356 // returns true on success and false on error - really an error is fatal 4357 // but this seems the normal response to library errors 4358 static bool do_suspend(OSThread* osthread) { 4359 assert(osthread->sr.is_running(), "thread should be running"); 4360 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4361 4362 // mark as suspended and send signal 4363 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4364 // failed to switch, state wasn't running? 4365 ShouldNotReachHere(); 4366 return false; 4367 } 4368 4369 if (sr_notify(osthread) != 0) { 4370 ShouldNotReachHere(); 4371 } 4372 4373 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4374 while (true) { 4375 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) { 4376 break; 4377 } else { 4378 // timeout 4379 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4380 if (cancelled == os::SuspendResume::SR_RUNNING) { 4381 return false; 4382 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4383 // make sure that we consume the signal on the semaphore as well 4384 sr_semaphore.wait(); 4385 break; 4386 } else { 4387 ShouldNotReachHere(); 4388 return false; 4389 } 4390 } 4391 } 4392 4393 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4394 return true; 4395 } 4396 4397 static void do_resume(OSThread* osthread) { 4398 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4399 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4400 4401 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4402 // failed to switch to WAKEUP_REQUEST 4403 ShouldNotReachHere(); 4404 return; 4405 } 4406 4407 while (true) { 4408 if (sr_notify(osthread) == 0) { 4409 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) { 4410 if (osthread->sr.is_running()) { 4411 return; 4412 } 4413 } 4414 } else { 4415 ShouldNotReachHere(); 4416 } 4417 } 4418 4419 guarantee(osthread->sr.is_running(), "Must be running!"); 4420 } 4421 4422 /////////////////////////////////////////////////////////////////////////////////// 4423 // signal handling (except suspend/resume) 4424 4425 // This routine may be used by user applications as a "hook" to catch signals. 4426 // The user-defined signal handler must pass unrecognized signals to this 4427 // routine, and if it returns true (non-zero), then the signal handler must 4428 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4429 // routine will never retun false (zero), but instead will execute a VM panic 4430 // routine kill the process. 4431 // 4432 // If this routine returns false, it is OK to call it again. This allows 4433 // the user-defined signal handler to perform checks either before or after 4434 // the VM performs its own checks. Naturally, the user code would be making 4435 // a serious error if it tried to handle an exception (such as a null check 4436 // or breakpoint) that the VM was generating for its own correct operation. 4437 // 4438 // This routine may recognize any of the following kinds of signals: 4439 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4440 // It should be consulted by handlers for any of those signals. 4441 // 4442 // The caller of this routine must pass in the three arguments supplied 4443 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4444 // field of the structure passed to sigaction(). This routine assumes that 4445 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4446 // 4447 // Note that the VM will print warnings if it detects conflicting signal 4448 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4449 // 4450 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4451 siginfo_t* siginfo, 4452 void* ucontext, 4453 int abort_if_unrecognized); 4454 4455 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4456 assert(info != NULL && uc != NULL, "it must be old kernel"); 4457 int orig_errno = errno; // Preserve errno value over signal handler. 4458 JVM_handle_linux_signal(sig, info, uc, true); 4459 errno = orig_errno; 4460 } 4461 4462 4463 // This boolean allows users to forward their own non-matching signals 4464 // to JVM_handle_linux_signal, harmlessly. 4465 bool os::Linux::signal_handlers_are_installed = false; 4466 4467 // For signal-chaining 4468 struct sigaction sigact[NSIG]; 4469 uint64_t sigs = 0; 4470 #if (64 < NSIG-1) 4471 #error "Not all signals can be encoded in sigs. Adapt its type!" 4472 #endif 4473 bool os::Linux::libjsig_is_loaded = false; 4474 typedef struct sigaction *(*get_signal_t)(int); 4475 get_signal_t os::Linux::get_signal_action = NULL; 4476 4477 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4478 struct sigaction *actp = NULL; 4479 4480 if (libjsig_is_loaded) { 4481 // Retrieve the old signal handler from libjsig 4482 actp = (*get_signal_action)(sig); 4483 } 4484 if (actp == NULL) { 4485 // Retrieve the preinstalled signal handler from jvm 4486 actp = get_preinstalled_handler(sig); 4487 } 4488 4489 return actp; 4490 } 4491 4492 static bool call_chained_handler(struct sigaction *actp, int sig, 4493 siginfo_t *siginfo, void *context) { 4494 // Call the old signal handler 4495 if (actp->sa_handler == SIG_DFL) { 4496 // It's more reasonable to let jvm treat it as an unexpected exception 4497 // instead of taking the default action. 4498 return false; 4499 } else if (actp->sa_handler != SIG_IGN) { 4500 if ((actp->sa_flags & SA_NODEFER) == 0) { 4501 // automaticlly block the signal 4502 sigaddset(&(actp->sa_mask), sig); 4503 } 4504 4505 sa_handler_t hand = NULL; 4506 sa_sigaction_t sa = NULL; 4507 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4508 // retrieve the chained handler 4509 if (siginfo_flag_set) { 4510 sa = actp->sa_sigaction; 4511 } else { 4512 hand = actp->sa_handler; 4513 } 4514 4515 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4516 actp->sa_handler = SIG_DFL; 4517 } 4518 4519 // try to honor the signal mask 4520 sigset_t oset; 4521 sigemptyset(&oset); 4522 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4523 4524 // call into the chained handler 4525 if (siginfo_flag_set) { 4526 (*sa)(sig, siginfo, context); 4527 } else { 4528 (*hand)(sig); 4529 } 4530 4531 // restore the signal mask 4532 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4533 } 4534 // Tell jvm's signal handler the signal is taken care of. 4535 return true; 4536 } 4537 4538 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4539 bool chained = false; 4540 // signal-chaining 4541 if (UseSignalChaining) { 4542 struct sigaction *actp = get_chained_signal_action(sig); 4543 if (actp != NULL) { 4544 chained = call_chained_handler(actp, sig, siginfo, context); 4545 } 4546 } 4547 return chained; 4548 } 4549 4550 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4551 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4552 return &sigact[sig]; 4553 } 4554 return NULL; 4555 } 4556 4557 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4558 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4559 sigact[sig] = oldAct; 4560 sigs |= (uint64_t)1 << (sig-1); 4561 } 4562 4563 // for diagnostic 4564 int sigflags[NSIG]; 4565 4566 int os::Linux::get_our_sigflags(int sig) { 4567 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4568 return sigflags[sig]; 4569 } 4570 4571 void os::Linux::set_our_sigflags(int sig, int flags) { 4572 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4573 if (sig > 0 && sig < NSIG) { 4574 sigflags[sig] = flags; 4575 } 4576 } 4577 4578 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4579 // Check for overwrite. 4580 struct sigaction oldAct; 4581 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4582 4583 void* oldhand = oldAct.sa_sigaction 4584 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4585 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4586 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4587 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4588 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4589 if (AllowUserSignalHandlers || !set_installed) { 4590 // Do not overwrite; user takes responsibility to forward to us. 4591 return; 4592 } else if (UseSignalChaining) { 4593 // save the old handler in jvm 4594 save_preinstalled_handler(sig, oldAct); 4595 // libjsig also interposes the sigaction() call below and saves the 4596 // old sigaction on it own. 4597 } else { 4598 fatal("Encountered unexpected pre-existing sigaction handler " 4599 "%#lx for signal %d.", (long)oldhand, sig); 4600 } 4601 } 4602 4603 struct sigaction sigAct; 4604 sigfillset(&(sigAct.sa_mask)); 4605 sigAct.sa_handler = SIG_DFL; 4606 if (!set_installed) { 4607 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4608 } else { 4609 sigAct.sa_sigaction = signalHandler; 4610 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4611 } 4612 // Save flags, which are set by ours 4613 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4614 sigflags[sig] = sigAct.sa_flags; 4615 4616 int ret = sigaction(sig, &sigAct, &oldAct); 4617 assert(ret == 0, "check"); 4618 4619 void* oldhand2 = oldAct.sa_sigaction 4620 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4621 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4622 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4623 } 4624 4625 // install signal handlers for signals that HotSpot needs to 4626 // handle in order to support Java-level exception handling. 4627 4628 void os::Linux::install_signal_handlers() { 4629 if (!signal_handlers_are_installed) { 4630 signal_handlers_are_installed = true; 4631 4632 // signal-chaining 4633 typedef void (*signal_setting_t)(); 4634 signal_setting_t begin_signal_setting = NULL; 4635 signal_setting_t end_signal_setting = NULL; 4636 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4637 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4638 if (begin_signal_setting != NULL) { 4639 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4640 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4641 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4642 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4643 libjsig_is_loaded = true; 4644 assert(UseSignalChaining, "should enable signal-chaining"); 4645 } 4646 if (libjsig_is_loaded) { 4647 // Tell libjsig jvm is setting signal handlers 4648 (*begin_signal_setting)(); 4649 } 4650 4651 set_signal_handler(SIGSEGV, true); 4652 set_signal_handler(SIGPIPE, true); 4653 set_signal_handler(SIGBUS, true); 4654 set_signal_handler(SIGILL, true); 4655 set_signal_handler(SIGFPE, true); 4656 #if defined(PPC64) 4657 set_signal_handler(SIGTRAP, true); 4658 #endif 4659 set_signal_handler(SIGXFSZ, true); 4660 4661 if (libjsig_is_loaded) { 4662 // Tell libjsig jvm finishes setting signal handlers 4663 (*end_signal_setting)(); 4664 } 4665 4666 // We don't activate signal checker if libjsig is in place, we trust ourselves 4667 // and if UserSignalHandler is installed all bets are off. 4668 // Log that signal checking is off only if -verbose:jni is specified. 4669 if (CheckJNICalls) { 4670 if (libjsig_is_loaded) { 4671 if (PrintJNIResolving) { 4672 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4673 } 4674 check_signals = false; 4675 } 4676 if (AllowUserSignalHandlers) { 4677 if (PrintJNIResolving) { 4678 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4679 } 4680 check_signals = false; 4681 } 4682 } 4683 } 4684 } 4685 4686 // This is the fastest way to get thread cpu time on Linux. 4687 // Returns cpu time (user+sys) for any thread, not only for current. 4688 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4689 // It might work on 2.6.10+ with a special kernel/glibc patch. 4690 // For reference, please, see IEEE Std 1003.1-2004: 4691 // http://www.unix.org/single_unix_specification 4692 4693 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4694 struct timespec tp; 4695 int rc = os::Linux::clock_gettime(clockid, &tp); 4696 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4697 4698 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4699 } 4700 4701 void os::Linux::initialize_os_info() { 4702 assert(_os_version == 0, "OS info already initialized"); 4703 4704 struct utsname _uname; 4705 4706 uint32_t major; 4707 uint32_t minor; 4708 uint32_t fix; 4709 4710 int rc; 4711 4712 // Kernel version is unknown if 4713 // verification below fails. 4714 _os_version = 0x01000000; 4715 4716 rc = uname(&_uname); 4717 if (rc != -1) { 4718 4719 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4720 if (rc == 3) { 4721 4722 if (major < 256 && minor < 256 && fix < 256) { 4723 // Kernel version format is as expected, 4724 // set it overriding unknown state. 4725 _os_version = (major << 16) | 4726 (minor << 8 ) | 4727 (fix << 0 ) ; 4728 } 4729 } 4730 } 4731 } 4732 4733 uint32_t os::Linux::os_version() { 4734 assert(_os_version != 0, "not initialized"); 4735 return _os_version & 0x00FFFFFF; 4736 } 4737 4738 bool os::Linux::os_version_is_known() { 4739 assert(_os_version != 0, "not initialized"); 4740 return _os_version & 0x01000000 ? false : true; 4741 } 4742 4743 ///// 4744 // glibc on Linux platform uses non-documented flag 4745 // to indicate, that some special sort of signal 4746 // trampoline is used. 4747 // We will never set this flag, and we should 4748 // ignore this flag in our diagnostic 4749 #ifdef SIGNIFICANT_SIGNAL_MASK 4750 #undef SIGNIFICANT_SIGNAL_MASK 4751 #endif 4752 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4753 4754 static const char* get_signal_handler_name(address handler, 4755 char* buf, int buflen) { 4756 int offset = 0; 4757 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4758 if (found) { 4759 // skip directory names 4760 const char *p1, *p2; 4761 p1 = buf; 4762 size_t len = strlen(os::file_separator()); 4763 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4764 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4765 } else { 4766 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4767 } 4768 return buf; 4769 } 4770 4771 static void print_signal_handler(outputStream* st, int sig, 4772 char* buf, size_t buflen) { 4773 struct sigaction sa; 4774 4775 sigaction(sig, NULL, &sa); 4776 4777 // See comment for SIGNIFICANT_SIGNAL_MASK define 4778 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4779 4780 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4781 4782 address handler = (sa.sa_flags & SA_SIGINFO) 4783 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4784 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4785 4786 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4787 st->print("SIG_DFL"); 4788 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4789 st->print("SIG_IGN"); 4790 } else { 4791 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4792 } 4793 4794 st->print(", sa_mask[0]="); 4795 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4796 4797 address rh = VMError::get_resetted_sighandler(sig); 4798 // May be, handler was resetted by VMError? 4799 if (rh != NULL) { 4800 handler = rh; 4801 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4802 } 4803 4804 st->print(", sa_flags="); 4805 os::Posix::print_sa_flags(st, sa.sa_flags); 4806 4807 // Check: is it our handler? 4808 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4809 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4810 // It is our signal handler 4811 // check for flags, reset system-used one! 4812 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4813 st->print( 4814 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4815 os::Linux::get_our_sigflags(sig)); 4816 } 4817 } 4818 st->cr(); 4819 } 4820 4821 4822 #define DO_SIGNAL_CHECK(sig) \ 4823 do { \ 4824 if (!sigismember(&check_signal_done, sig)) { \ 4825 os::Linux::check_signal_handler(sig); \ 4826 } \ 4827 } while (0) 4828 4829 // This method is a periodic task to check for misbehaving JNI applications 4830 // under CheckJNI, we can add any periodic checks here 4831 4832 void os::run_periodic_checks() { 4833 if (check_signals == false) return; 4834 4835 // SEGV and BUS if overridden could potentially prevent 4836 // generation of hs*.log in the event of a crash, debugging 4837 // such a case can be very challenging, so we absolutely 4838 // check the following for a good measure: 4839 DO_SIGNAL_CHECK(SIGSEGV); 4840 DO_SIGNAL_CHECK(SIGILL); 4841 DO_SIGNAL_CHECK(SIGFPE); 4842 DO_SIGNAL_CHECK(SIGBUS); 4843 DO_SIGNAL_CHECK(SIGPIPE); 4844 DO_SIGNAL_CHECK(SIGXFSZ); 4845 #if defined(PPC64) 4846 DO_SIGNAL_CHECK(SIGTRAP); 4847 #endif 4848 4849 // ReduceSignalUsage allows the user to override these handlers 4850 // see comments at the very top and jvm_md.h 4851 if (!ReduceSignalUsage) { 4852 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4853 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4854 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4855 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4856 } 4857 4858 DO_SIGNAL_CHECK(SR_signum); 4859 } 4860 4861 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4862 4863 static os_sigaction_t os_sigaction = NULL; 4864 4865 void os::Linux::check_signal_handler(int sig) { 4866 char buf[O_BUFLEN]; 4867 address jvmHandler = NULL; 4868 4869 4870 struct sigaction act; 4871 if (os_sigaction == NULL) { 4872 // only trust the default sigaction, in case it has been interposed 4873 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4874 if (os_sigaction == NULL) return; 4875 } 4876 4877 os_sigaction(sig, (struct sigaction*)NULL, &act); 4878 4879 4880 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4881 4882 address thisHandler = (act.sa_flags & SA_SIGINFO) 4883 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4884 : CAST_FROM_FN_PTR(address, act.sa_handler); 4885 4886 4887 switch (sig) { 4888 case SIGSEGV: 4889 case SIGBUS: 4890 case SIGFPE: 4891 case SIGPIPE: 4892 case SIGILL: 4893 case SIGXFSZ: 4894 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4895 break; 4896 4897 case SHUTDOWN1_SIGNAL: 4898 case SHUTDOWN2_SIGNAL: 4899 case SHUTDOWN3_SIGNAL: 4900 case BREAK_SIGNAL: 4901 jvmHandler = (address)user_handler(); 4902 break; 4903 4904 default: 4905 if (sig == SR_signum) { 4906 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4907 } else { 4908 return; 4909 } 4910 break; 4911 } 4912 4913 if (thisHandler != jvmHandler) { 4914 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4915 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4916 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4917 // No need to check this sig any longer 4918 sigaddset(&check_signal_done, sig); 4919 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4920 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4921 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4922 exception_name(sig, buf, O_BUFLEN)); 4923 } 4924 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4925 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4926 tty->print("expected:"); 4927 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4928 tty->cr(); 4929 tty->print(" found:"); 4930 os::Posix::print_sa_flags(tty, act.sa_flags); 4931 tty->cr(); 4932 // No need to check this sig any longer 4933 sigaddset(&check_signal_done, sig); 4934 } 4935 4936 // Dump all the signal 4937 if (sigismember(&check_signal_done, sig)) { 4938 print_signal_handlers(tty, buf, O_BUFLEN); 4939 } 4940 } 4941 4942 extern void report_error(char* file_name, int line_no, char* title, 4943 char* format, ...); 4944 4945 // this is called _before_ most of the global arguments have been parsed 4946 void os::init(void) { 4947 char dummy; // used to get a guess on initial stack address 4948 4949 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4950 4951 init_random(1234567); 4952 4953 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4954 if (Linux::page_size() == -1) { 4955 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4956 os::strerror(errno)); 4957 } 4958 init_page_sizes((size_t) Linux::page_size()); 4959 4960 Linux::initialize_system_info(); 4961 4962 Linux::initialize_os_info(); 4963 4964 // _main_thread points to the thread that created/loaded the JVM. 4965 Linux::_main_thread = pthread_self(); 4966 4967 Linux::clock_init(); 4968 initial_time_count = javaTimeNanos(); 4969 4970 // retrieve entry point for pthread_setname_np 4971 Linux::_pthread_setname_np = 4972 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4973 4974 os::Posix::init(); 4975 } 4976 4977 // To install functions for atexit system call 4978 extern "C" { 4979 static void perfMemory_exit_helper() { 4980 perfMemory_exit(); 4981 } 4982 } 4983 4984 void os::pd_init_container_support() { 4985 OSContainer::init(); 4986 } 4987 4988 // this is called _after_ the global arguments have been parsed 4989 jint os::init_2(void) { 4990 4991 os::Posix::init_2(); 4992 4993 Linux::fast_thread_clock_init(); 4994 4995 // initialize suspend/resume support - must do this before signal_sets_init() 4996 if (SR_initialize() != 0) { 4997 perror("SR_initialize failed"); 4998 return JNI_ERR; 4999 } 5000 5001 Linux::signal_sets_init(); 5002 Linux::install_signal_handlers(); 5003 // Initialize data for jdk.internal.misc.Signal 5004 if (!ReduceSignalUsage) { 5005 signal_init_pd(); 5006 } 5007 5008 // Check and sets minimum stack sizes against command line options 5009 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 5010 return JNI_ERR; 5011 } 5012 5013 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 5014 if (!suppress_primordial_thread_resolution) { 5015 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5016 } 5017 5018 #if defined(IA32) 5019 workaround_expand_exec_shield_cs_limit(); 5020 #endif 5021 5022 Linux::libpthread_init(); 5023 Linux::sched_getcpu_init(); 5024 log_info(os)("HotSpot is running with %s, %s", 5025 Linux::glibc_version(), Linux::libpthread_version()); 5026 5027 if (UseNUMA) { 5028 if (!Linux::libnuma_init()) { 5029 UseNUMA = false; 5030 } else { 5031 if ((Linux::numa_max_node() < 1)) { 5032 // There's only one node(they start from 0), disable NUMA. 5033 UseNUMA = false; 5034 } 5035 } 5036 5037 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5038 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5039 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5040 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5041 // and disable adaptive resizing. 5042 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5043 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5044 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5045 UseAdaptiveSizePolicy = false; 5046 UseAdaptiveNUMAChunkSizing = false; 5047 } 5048 } 5049 5050 if (!UseNUMA && ForceNUMA) { 5051 UseNUMA = true; 5052 } 5053 } 5054 5055 if (MaxFDLimit) { 5056 // set the number of file descriptors to max. print out error 5057 // if getrlimit/setrlimit fails but continue regardless. 5058 struct rlimit nbr_files; 5059 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5060 if (status != 0) { 5061 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5062 } else { 5063 nbr_files.rlim_cur = nbr_files.rlim_max; 5064 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5065 if (status != 0) { 5066 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5067 } 5068 } 5069 } 5070 5071 // Initialize lock used to serialize thread creation (see os::create_thread) 5072 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 5073 5074 // at-exit methods are called in the reverse order of their registration. 5075 // atexit functions are called on return from main or as a result of a 5076 // call to exit(3C). There can be only 32 of these functions registered 5077 // and atexit() does not set errno. 5078 5079 if (PerfAllowAtExitRegistration) { 5080 // only register atexit functions if PerfAllowAtExitRegistration is set. 5081 // atexit functions can be delayed until process exit time, which 5082 // can be problematic for embedded VM situations. Embedded VMs should 5083 // call DestroyJavaVM() to assure that VM resources are released. 5084 5085 // note: perfMemory_exit_helper atexit function may be removed in 5086 // the future if the appropriate cleanup code can be added to the 5087 // VM_Exit VMOperation's doit method. 5088 if (atexit(perfMemory_exit_helper) != 0) { 5089 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5090 } 5091 } 5092 5093 // initialize thread priority policy 5094 prio_init(); 5095 5096 if (!FLAG_IS_DEFAULT(AllocateHeapAt)) { 5097 set_coredump_filter(false /*largepages*/, true /*dax_shared*/); 5098 } 5099 return JNI_OK; 5100 } 5101 5102 // Mark the polling page as unreadable 5103 void os::make_polling_page_unreadable(void) { 5104 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 5105 fatal("Could not disable polling page"); 5106 } 5107 } 5108 5109 // Mark the polling page as readable 5110 void os::make_polling_page_readable(void) { 5111 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 5112 fatal("Could not enable polling page"); 5113 } 5114 } 5115 5116 // older glibc versions don't have this macro (which expands to 5117 // an optimized bit-counting function) so we have to roll our own 5118 #ifndef CPU_COUNT 5119 5120 static int _cpu_count(const cpu_set_t* cpus) { 5121 int count = 0; 5122 // only look up to the number of configured processors 5123 for (int i = 0; i < os::processor_count(); i++) { 5124 if (CPU_ISSET(i, cpus)) { 5125 count++; 5126 } 5127 } 5128 return count; 5129 } 5130 5131 #define CPU_COUNT(cpus) _cpu_count(cpus) 5132 5133 #endif // CPU_COUNT 5134 5135 // Get the current number of available processors for this process. 5136 // This value can change at any time during a process's lifetime. 5137 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5138 // If it appears there may be more than 1024 processors then we do a 5139 // dynamic check - see 6515172 for details. 5140 // If anything goes wrong we fallback to returning the number of online 5141 // processors - which can be greater than the number available to the process. 5142 int os::Linux::active_processor_count() { 5143 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5144 cpu_set_t* cpus_p = &cpus; 5145 int cpus_size = sizeof(cpu_set_t); 5146 5147 int configured_cpus = os::processor_count(); // upper bound on available cpus 5148 int cpu_count = 0; 5149 5150 // old build platforms may not support dynamic cpu sets 5151 #ifdef CPU_ALLOC 5152 5153 // To enable easy testing of the dynamic path on different platforms we 5154 // introduce a diagnostic flag: UseCpuAllocPath 5155 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5156 // kernel may use a mask bigger than cpu_set_t 5157 log_trace(os)("active_processor_count: using dynamic path %s" 5158 "- configured processors: %d", 5159 UseCpuAllocPath ? "(forced) " : "", 5160 configured_cpus); 5161 cpus_p = CPU_ALLOC(configured_cpus); 5162 if (cpus_p != NULL) { 5163 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5164 // zero it just to be safe 5165 CPU_ZERO_S(cpus_size, cpus_p); 5166 } 5167 else { 5168 // failed to allocate so fallback to online cpus 5169 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5170 log_trace(os)("active_processor_count: " 5171 "CPU_ALLOC failed (%s) - using " 5172 "online processor count: %d", 5173 os::strerror(errno), online_cpus); 5174 return online_cpus; 5175 } 5176 } 5177 else { 5178 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5179 configured_cpus); 5180 } 5181 #else // CPU_ALLOC 5182 // these stubs won't be executed 5183 #define CPU_COUNT_S(size, cpus) -1 5184 #define CPU_FREE(cpus) 5185 5186 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5187 configured_cpus); 5188 #endif // CPU_ALLOC 5189 5190 // pid 0 means the current thread - which we have to assume represents the process 5191 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5192 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5193 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5194 } 5195 else { 5196 cpu_count = CPU_COUNT(cpus_p); 5197 } 5198 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5199 } 5200 else { 5201 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5202 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5203 "which may exceed available processors", os::strerror(errno), cpu_count); 5204 } 5205 5206 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5207 CPU_FREE(cpus_p); 5208 } 5209 5210 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5211 return cpu_count; 5212 } 5213 5214 // Determine the active processor count from one of 5215 // three different sources: 5216 // 5217 // 1. User option -XX:ActiveProcessorCount 5218 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5219 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5220 // 5221 // Option 1, if specified, will always override. 5222 // If the cgroup subsystem is active and configured, we 5223 // will return the min of the cgroup and option 2 results. 5224 // This is required since tools, such as numactl, that 5225 // alter cpu affinity do not update cgroup subsystem 5226 // cpuset configuration files. 5227 int os::active_processor_count() { 5228 // User has overridden the number of active processors 5229 if (ActiveProcessorCount > 0) { 5230 log_trace(os)("active_processor_count: " 5231 "active processor count set by user : %d", 5232 ActiveProcessorCount); 5233 return ActiveProcessorCount; 5234 } 5235 5236 int active_cpus; 5237 if (OSContainer::is_containerized()) { 5238 active_cpus = OSContainer::active_processor_count(); 5239 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5240 active_cpus); 5241 } else { 5242 active_cpus = os::Linux::active_processor_count(); 5243 } 5244 5245 return active_cpus; 5246 } 5247 5248 void os::set_native_thread_name(const char *name) { 5249 if (Linux::_pthread_setname_np) { 5250 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5251 snprintf(buf, sizeof(buf), "%s", name); 5252 buf[sizeof(buf) - 1] = '\0'; 5253 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5254 // ERANGE should not happen; all other errors should just be ignored. 5255 assert(rc != ERANGE, "pthread_setname_np failed"); 5256 } 5257 } 5258 5259 bool os::distribute_processes(uint length, uint* distribution) { 5260 // Not yet implemented. 5261 return false; 5262 } 5263 5264 bool os::bind_to_processor(uint processor_id) { 5265 // Not yet implemented. 5266 return false; 5267 } 5268 5269 /// 5270 5271 void os::SuspendedThreadTask::internal_do_task() { 5272 if (do_suspend(_thread->osthread())) { 5273 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5274 do_task(context); 5275 do_resume(_thread->osthread()); 5276 } 5277 } 5278 5279 //////////////////////////////////////////////////////////////////////////////// 5280 // debug support 5281 5282 bool os::find(address addr, outputStream* st) { 5283 Dl_info dlinfo; 5284 memset(&dlinfo, 0, sizeof(dlinfo)); 5285 if (dladdr(addr, &dlinfo) != 0) { 5286 st->print(PTR_FORMAT ": ", p2i(addr)); 5287 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5288 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5289 p2i(addr) - p2i(dlinfo.dli_saddr)); 5290 } else if (dlinfo.dli_fbase != NULL) { 5291 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5292 } else { 5293 st->print("<absolute address>"); 5294 } 5295 if (dlinfo.dli_fname != NULL) { 5296 st->print(" in %s", dlinfo.dli_fname); 5297 } 5298 if (dlinfo.dli_fbase != NULL) { 5299 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5300 } 5301 st->cr(); 5302 5303 if (Verbose) { 5304 // decode some bytes around the PC 5305 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5306 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5307 address lowest = (address) dlinfo.dli_sname; 5308 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5309 if (begin < lowest) begin = lowest; 5310 Dl_info dlinfo2; 5311 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5312 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5313 end = (address) dlinfo2.dli_saddr; 5314 } 5315 Disassembler::decode(begin, end, st); 5316 } 5317 return true; 5318 } 5319 return false; 5320 } 5321 5322 //////////////////////////////////////////////////////////////////////////////// 5323 // misc 5324 5325 // This does not do anything on Linux. This is basically a hook for being 5326 // able to use structured exception handling (thread-local exception filters) 5327 // on, e.g., Win32. 5328 void 5329 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5330 JavaCallArguments* args, Thread* thread) { 5331 f(value, method, args, thread); 5332 } 5333 5334 void os::print_statistics() { 5335 } 5336 5337 bool os::message_box(const char* title, const char* message) { 5338 int i; 5339 fdStream err(defaultStream::error_fd()); 5340 for (i = 0; i < 78; i++) err.print_raw("="); 5341 err.cr(); 5342 err.print_raw_cr(title); 5343 for (i = 0; i < 78; i++) err.print_raw("-"); 5344 err.cr(); 5345 err.print_raw_cr(message); 5346 for (i = 0; i < 78; i++) err.print_raw("="); 5347 err.cr(); 5348 5349 char buf[16]; 5350 // Prevent process from exiting upon "read error" without consuming all CPU 5351 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5352 5353 return buf[0] == 'y' || buf[0] == 'Y'; 5354 } 5355 5356 int os::stat(const char *path, struct stat *sbuf) { 5357 char pathbuf[MAX_PATH]; 5358 if (strlen(path) > MAX_PATH - 1) { 5359 errno = ENAMETOOLONG; 5360 return -1; 5361 } 5362 os::native_path(strcpy(pathbuf, path)); 5363 return ::stat(pathbuf, sbuf); 5364 } 5365 5366 // Is a (classpath) directory empty? 5367 bool os::dir_is_empty(const char* path) { 5368 DIR *dir = NULL; 5369 struct dirent *ptr; 5370 5371 dir = opendir(path); 5372 if (dir == NULL) return true; 5373 5374 // Scan the directory 5375 bool result = true; 5376 char buf[sizeof(struct dirent) + MAX_PATH]; 5377 while (result && (ptr = ::readdir(dir)) != NULL) { 5378 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5379 result = false; 5380 } 5381 } 5382 closedir(dir); 5383 return result; 5384 } 5385 5386 // This code originates from JDK's sysOpen and open64_w 5387 // from src/solaris/hpi/src/system_md.c 5388 5389 int os::open(const char *path, int oflag, int mode) { 5390 if (strlen(path) > MAX_PATH - 1) { 5391 errno = ENAMETOOLONG; 5392 return -1; 5393 } 5394 5395 // All file descriptors that are opened in the Java process and not 5396 // specifically destined for a subprocess should have the close-on-exec 5397 // flag set. If we don't set it, then careless 3rd party native code 5398 // might fork and exec without closing all appropriate file descriptors 5399 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5400 // turn might: 5401 // 5402 // - cause end-of-file to fail to be detected on some file 5403 // descriptors, resulting in mysterious hangs, or 5404 // 5405 // - might cause an fopen in the subprocess to fail on a system 5406 // suffering from bug 1085341. 5407 // 5408 // (Yes, the default setting of the close-on-exec flag is a Unix 5409 // design flaw) 5410 // 5411 // See: 5412 // 1085341: 32-bit stdio routines should support file descriptors >255 5413 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5414 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5415 // 5416 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5417 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5418 // because it saves a system call and removes a small window where the flag 5419 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5420 // and we fall back to using FD_CLOEXEC (see below). 5421 #ifdef O_CLOEXEC 5422 oflag |= O_CLOEXEC; 5423 #endif 5424 5425 int fd = ::open64(path, oflag, mode); 5426 if (fd == -1) return -1; 5427 5428 //If the open succeeded, the file might still be a directory 5429 { 5430 struct stat64 buf64; 5431 int ret = ::fstat64(fd, &buf64); 5432 int st_mode = buf64.st_mode; 5433 5434 if (ret != -1) { 5435 if ((st_mode & S_IFMT) == S_IFDIR) { 5436 errno = EISDIR; 5437 ::close(fd); 5438 return -1; 5439 } 5440 } else { 5441 ::close(fd); 5442 return -1; 5443 } 5444 } 5445 5446 #ifdef FD_CLOEXEC 5447 // Validate that the use of the O_CLOEXEC flag on open above worked. 5448 // With recent kernels, we will perform this check exactly once. 5449 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5450 if (!O_CLOEXEC_is_known_to_work) { 5451 int flags = ::fcntl(fd, F_GETFD); 5452 if (flags != -1) { 5453 if ((flags & FD_CLOEXEC) != 0) 5454 O_CLOEXEC_is_known_to_work = 1; 5455 else 5456 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5457 } 5458 } 5459 #endif 5460 5461 return fd; 5462 } 5463 5464 5465 // create binary file, rewriting existing file if required 5466 int os::create_binary_file(const char* path, bool rewrite_existing) { 5467 int oflags = O_WRONLY | O_CREAT; 5468 if (!rewrite_existing) { 5469 oflags |= O_EXCL; 5470 } 5471 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5472 } 5473 5474 // return current position of file pointer 5475 jlong os::current_file_offset(int fd) { 5476 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5477 } 5478 5479 // move file pointer to the specified offset 5480 jlong os::seek_to_file_offset(int fd, jlong offset) { 5481 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5482 } 5483 5484 // This code originates from JDK's sysAvailable 5485 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5486 5487 int os::available(int fd, jlong *bytes) { 5488 jlong cur, end; 5489 int mode; 5490 struct stat64 buf64; 5491 5492 if (::fstat64(fd, &buf64) >= 0) { 5493 mode = buf64.st_mode; 5494 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5495 int n; 5496 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5497 *bytes = n; 5498 return 1; 5499 } 5500 } 5501 } 5502 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5503 return 0; 5504 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5505 return 0; 5506 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5507 return 0; 5508 } 5509 *bytes = end - cur; 5510 return 1; 5511 } 5512 5513 // Map a block of memory. 5514 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5515 char *addr, size_t bytes, bool read_only, 5516 bool allow_exec) { 5517 int prot; 5518 int flags = MAP_PRIVATE; 5519 5520 if (read_only) { 5521 prot = PROT_READ; 5522 } else { 5523 prot = PROT_READ | PROT_WRITE; 5524 } 5525 5526 if (allow_exec) { 5527 prot |= PROT_EXEC; 5528 } 5529 5530 if (addr != NULL) { 5531 flags |= MAP_FIXED; 5532 } 5533 5534 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5535 fd, file_offset); 5536 if (mapped_address == MAP_FAILED) { 5537 return NULL; 5538 } 5539 return mapped_address; 5540 } 5541 5542 5543 // Remap a block of memory. 5544 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5545 char *addr, size_t bytes, bool read_only, 5546 bool allow_exec) { 5547 // same as map_memory() on this OS 5548 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5549 allow_exec); 5550 } 5551 5552 5553 // Unmap a block of memory. 5554 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5555 return munmap(addr, bytes) == 0; 5556 } 5557 5558 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5559 5560 static clockid_t thread_cpu_clockid(Thread* thread) { 5561 pthread_t tid = thread->osthread()->pthread_id(); 5562 clockid_t clockid; 5563 5564 // Get thread clockid 5565 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5566 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5567 return clockid; 5568 } 5569 5570 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5571 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5572 // of a thread. 5573 // 5574 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5575 // the fast estimate available on the platform. 5576 5577 jlong os::current_thread_cpu_time() { 5578 if (os::Linux::supports_fast_thread_cpu_time()) { 5579 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5580 } else { 5581 // return user + sys since the cost is the same 5582 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5583 } 5584 } 5585 5586 jlong os::thread_cpu_time(Thread* thread) { 5587 // consistent with what current_thread_cpu_time() returns 5588 if (os::Linux::supports_fast_thread_cpu_time()) { 5589 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5590 } else { 5591 return slow_thread_cpu_time(thread, true /* user + sys */); 5592 } 5593 } 5594 5595 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5596 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5597 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5598 } else { 5599 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5600 } 5601 } 5602 5603 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5604 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5605 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5606 } else { 5607 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5608 } 5609 } 5610 5611 // -1 on error. 5612 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5613 pid_t tid = thread->osthread()->thread_id(); 5614 char *s; 5615 char stat[2048]; 5616 int statlen; 5617 char proc_name[64]; 5618 int count; 5619 long sys_time, user_time; 5620 char cdummy; 5621 int idummy; 5622 long ldummy; 5623 FILE *fp; 5624 5625 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5626 fp = fopen(proc_name, "r"); 5627 if (fp == NULL) return -1; 5628 statlen = fread(stat, 1, 2047, fp); 5629 stat[statlen] = '\0'; 5630 fclose(fp); 5631 5632 // Skip pid and the command string. Note that we could be dealing with 5633 // weird command names, e.g. user could decide to rename java launcher 5634 // to "java 1.4.2 :)", then the stat file would look like 5635 // 1234 (java 1.4.2 :)) R ... ... 5636 // We don't really need to know the command string, just find the last 5637 // occurrence of ")" and then start parsing from there. See bug 4726580. 5638 s = strrchr(stat, ')'); 5639 if (s == NULL) return -1; 5640 5641 // Skip blank chars 5642 do { s++; } while (s && isspace(*s)); 5643 5644 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5645 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5646 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5647 &user_time, &sys_time); 5648 if (count != 13) return -1; 5649 if (user_sys_cpu_time) { 5650 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5651 } else { 5652 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5653 } 5654 } 5655 5656 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5657 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5658 info_ptr->may_skip_backward = false; // elapsed time not wall time 5659 info_ptr->may_skip_forward = false; // elapsed time not wall time 5660 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5661 } 5662 5663 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5664 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5665 info_ptr->may_skip_backward = false; // elapsed time not wall time 5666 info_ptr->may_skip_forward = false; // elapsed time not wall time 5667 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5668 } 5669 5670 bool os::is_thread_cpu_time_supported() { 5671 return true; 5672 } 5673 5674 // System loadavg support. Returns -1 if load average cannot be obtained. 5675 // Linux doesn't yet have a (official) notion of processor sets, 5676 // so just return the system wide load average. 5677 int os::loadavg(double loadavg[], int nelem) { 5678 return ::getloadavg(loadavg, nelem); 5679 } 5680 5681 void os::pause() { 5682 char filename[MAX_PATH]; 5683 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5684 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5685 } else { 5686 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5687 } 5688 5689 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5690 if (fd != -1) { 5691 struct stat buf; 5692 ::close(fd); 5693 while (::stat(filename, &buf) == 0) { 5694 (void)::poll(NULL, 0, 100); 5695 } 5696 } else { 5697 jio_fprintf(stderr, 5698 "Could not open pause file '%s', continuing immediately.\n", filename); 5699 } 5700 } 5701 5702 extern char** environ; 5703 5704 // Run the specified command in a separate process. Return its exit value, 5705 // or -1 on failure (e.g. can't fork a new process). 5706 // Unlike system(), this function can be called from signal handler. It 5707 // doesn't block SIGINT et al. 5708 int os::fork_and_exec(char* cmd) { 5709 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5710 5711 pid_t pid = fork(); 5712 5713 if (pid < 0) { 5714 // fork failed 5715 return -1; 5716 5717 } else if (pid == 0) { 5718 // child process 5719 5720 execve("/bin/sh", (char* const*)argv, environ); 5721 5722 // execve failed 5723 _exit(-1); 5724 5725 } else { 5726 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5727 // care about the actual exit code, for now. 5728 5729 int status; 5730 5731 // Wait for the child process to exit. This returns immediately if 5732 // the child has already exited. */ 5733 while (waitpid(pid, &status, 0) < 0) { 5734 switch (errno) { 5735 case ECHILD: return 0; 5736 case EINTR: break; 5737 default: return -1; 5738 } 5739 } 5740 5741 if (WIFEXITED(status)) { 5742 // The child exited normally; get its exit code. 5743 return WEXITSTATUS(status); 5744 } else if (WIFSIGNALED(status)) { 5745 // The child exited because of a signal 5746 // The best value to return is 0x80 + signal number, 5747 // because that is what all Unix shells do, and because 5748 // it allows callers to distinguish between process exit and 5749 // process death by signal. 5750 return 0x80 + WTERMSIG(status); 5751 } else { 5752 // Unknown exit code; pass it through 5753 return status; 5754 } 5755 } 5756 } 5757 5758 // Get the default path to the core file 5759 // Returns the length of the string 5760 int os::get_core_path(char* buffer, size_t bufferSize) { 5761 /* 5762 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5763 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5764 */ 5765 const int core_pattern_len = 129; 5766 char core_pattern[core_pattern_len] = {0}; 5767 5768 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5769 if (core_pattern_file == -1) { 5770 return -1; 5771 } 5772 5773 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5774 ::close(core_pattern_file); 5775 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5776 return -1; 5777 } 5778 if (core_pattern[ret-1] == '\n') { 5779 core_pattern[ret-1] = '\0'; 5780 } else { 5781 core_pattern[ret] = '\0'; 5782 } 5783 5784 char *pid_pos = strstr(core_pattern, "%p"); 5785 int written; 5786 5787 if (core_pattern[0] == '/') { 5788 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5789 } else { 5790 char cwd[PATH_MAX]; 5791 5792 const char* p = get_current_directory(cwd, PATH_MAX); 5793 if (p == NULL) { 5794 return -1; 5795 } 5796 5797 if (core_pattern[0] == '|') { 5798 written = jio_snprintf(buffer, bufferSize, 5799 "\"%s\" (or dumping to %s/core.%d)", 5800 &core_pattern[1], p, current_process_id()); 5801 } else { 5802 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5803 } 5804 } 5805 5806 if (written < 0) { 5807 return -1; 5808 } 5809 5810 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5811 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5812 5813 if (core_uses_pid_file != -1) { 5814 char core_uses_pid = 0; 5815 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5816 ::close(core_uses_pid_file); 5817 5818 if (core_uses_pid == '1') { 5819 jio_snprintf(buffer + written, bufferSize - written, 5820 ".%d", current_process_id()); 5821 } 5822 } 5823 } 5824 5825 return strlen(buffer); 5826 } 5827 5828 bool os::start_debugging(char *buf, int buflen) { 5829 int len = (int)strlen(buf); 5830 char *p = &buf[len]; 5831 5832 jio_snprintf(p, buflen-len, 5833 "\n\n" 5834 "Do you want to debug the problem?\n\n" 5835 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5836 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5837 "Otherwise, press RETURN to abort...", 5838 os::current_process_id(), os::current_process_id(), 5839 os::current_thread_id(), os::current_thread_id()); 5840 5841 bool yes = os::message_box("Unexpected Error", buf); 5842 5843 if (yes) { 5844 // yes, user asked VM to launch debugger 5845 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 5846 os::current_process_id(), os::current_process_id()); 5847 5848 os::fork_and_exec(buf); 5849 yes = false; 5850 } 5851 return yes; 5852 } 5853 5854 5855 // Java/Compiler thread: 5856 // 5857 // Low memory addresses 5858 // P0 +------------------------+ 5859 // | |\ Java thread created by VM does not have glibc 5860 // | glibc guard page | - guard page, attached Java thread usually has 5861 // | |/ 1 glibc guard page. 5862 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5863 // | |\ 5864 // | HotSpot Guard Pages | - red, yellow and reserved pages 5865 // | |/ 5866 // +------------------------+ JavaThread::stack_reserved_zone_base() 5867 // | |\ 5868 // | Normal Stack | - 5869 // | |/ 5870 // P2 +------------------------+ Thread::stack_base() 5871 // 5872 // Non-Java thread: 5873 // 5874 // Low memory addresses 5875 // P0 +------------------------+ 5876 // | |\ 5877 // | glibc guard page | - usually 1 page 5878 // | |/ 5879 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5880 // | |\ 5881 // | Normal Stack | - 5882 // | |/ 5883 // P2 +------------------------+ Thread::stack_base() 5884 // 5885 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 5886 // returned from pthread_attr_getstack(). 5887 // ** Due to NPTL implementation error, linux takes the glibc guard page out 5888 // of the stack size given in pthread_attr. We work around this for 5889 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 5890 // 5891 #ifndef ZERO 5892 static void current_stack_region(address * bottom, size_t * size) { 5893 if (os::is_primordial_thread()) { 5894 // primordial thread needs special handling because pthread_getattr_np() 5895 // may return bogus value. 5896 *bottom = os::Linux::initial_thread_stack_bottom(); 5897 *size = os::Linux::initial_thread_stack_size(); 5898 } else { 5899 pthread_attr_t attr; 5900 5901 int rslt = pthread_getattr_np(pthread_self(), &attr); 5902 5903 // JVM needs to know exact stack location, abort if it fails 5904 if (rslt != 0) { 5905 if (rslt == ENOMEM) { 5906 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 5907 } else { 5908 fatal("pthread_getattr_np failed with error = %d", rslt); 5909 } 5910 } 5911 5912 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 5913 fatal("Cannot locate current stack attributes!"); 5914 } 5915 5916 // Work around NPTL stack guard error. 5917 size_t guard_size = 0; 5918 rslt = pthread_attr_getguardsize(&attr, &guard_size); 5919 if (rslt != 0) { 5920 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 5921 } 5922 *bottom += guard_size; 5923 *size -= guard_size; 5924 5925 pthread_attr_destroy(&attr); 5926 5927 } 5928 assert(os::current_stack_pointer() >= *bottom && 5929 os::current_stack_pointer() < *bottom + *size, "just checking"); 5930 } 5931 5932 address os::current_stack_base() { 5933 address bottom; 5934 size_t size; 5935 current_stack_region(&bottom, &size); 5936 return (bottom + size); 5937 } 5938 5939 size_t os::current_stack_size() { 5940 // This stack size includes the usable stack and HotSpot guard pages 5941 // (for the threads that have Hotspot guard pages). 5942 address bottom; 5943 size_t size; 5944 current_stack_region(&bottom, &size); 5945 return size; 5946 } 5947 #endif 5948 5949 static inline struct timespec get_mtime(const char* filename) { 5950 struct stat st; 5951 int ret = os::stat(filename, &st); 5952 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 5953 return st.st_mtim; 5954 } 5955 5956 int os::compare_file_modified_times(const char* file1, const char* file2) { 5957 struct timespec filetime1 = get_mtime(file1); 5958 struct timespec filetime2 = get_mtime(file2); 5959 int diff = filetime1.tv_sec - filetime2.tv_sec; 5960 if (diff == 0) { 5961 return filetime1.tv_nsec - filetime2.tv_nsec; 5962 } 5963 return diff; 5964 } 5965 5966 /////////////// Unit tests /////////////// 5967 5968 #ifndef PRODUCT 5969 5970 #define test_log(...) \ 5971 do { \ 5972 if (VerboseInternalVMTests) { \ 5973 tty->print_cr(__VA_ARGS__); \ 5974 tty->flush(); \ 5975 } \ 5976 } while (false) 5977 5978 class TestReserveMemorySpecial : AllStatic { 5979 public: 5980 static void small_page_write(void* addr, size_t size) { 5981 size_t page_size = os::vm_page_size(); 5982 5983 char* end = (char*)addr + size; 5984 for (char* p = (char*)addr; p < end; p += page_size) { 5985 *p = 1; 5986 } 5987 } 5988 5989 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 5990 if (!UseHugeTLBFS) { 5991 return; 5992 } 5993 5994 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 5995 5996 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 5997 5998 if (addr != NULL) { 5999 small_page_write(addr, size); 6000 6001 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6002 } 6003 } 6004 6005 static void test_reserve_memory_special_huge_tlbfs_only() { 6006 if (!UseHugeTLBFS) { 6007 return; 6008 } 6009 6010 size_t lp = os::large_page_size(); 6011 6012 for (size_t size = lp; size <= lp * 10; size += lp) { 6013 test_reserve_memory_special_huge_tlbfs_only(size); 6014 } 6015 } 6016 6017 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6018 size_t lp = os::large_page_size(); 6019 size_t ag = os::vm_allocation_granularity(); 6020 6021 // sizes to test 6022 const size_t sizes[] = { 6023 lp, lp + ag, lp + lp / 2, lp * 2, 6024 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6025 lp * 10, lp * 10 + lp / 2 6026 }; 6027 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6028 6029 // For each size/alignment combination, we test three scenarios: 6030 // 1) with req_addr == NULL 6031 // 2) with a non-null req_addr at which we expect to successfully allocate 6032 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6033 // expect the allocation to either fail or to ignore req_addr 6034 6035 // Pre-allocate two areas; they shall be as large as the largest allocation 6036 // and aligned to the largest alignment we will be testing. 6037 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6038 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6039 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6040 -1, 0); 6041 assert(mapping1 != MAP_FAILED, "should work"); 6042 6043 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6044 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6045 -1, 0); 6046 assert(mapping2 != MAP_FAILED, "should work"); 6047 6048 // Unmap the first mapping, but leave the second mapping intact: the first 6049 // mapping will serve as a value for a "good" req_addr (case 2). The second 6050 // mapping, still intact, as "bad" req_addr (case 3). 6051 ::munmap(mapping1, mapping_size); 6052 6053 // Case 1 6054 test_log("%s, req_addr NULL:", __FUNCTION__); 6055 test_log("size align result"); 6056 6057 for (int i = 0; i < num_sizes; i++) { 6058 const size_t size = sizes[i]; 6059 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6060 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6061 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6062 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6063 if (p != NULL) { 6064 assert(is_aligned(p, alignment), "must be"); 6065 small_page_write(p, size); 6066 os::Linux::release_memory_special_huge_tlbfs(p, size); 6067 } 6068 } 6069 } 6070 6071 // Case 2 6072 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6073 test_log("size align req_addr result"); 6074 6075 for (int i = 0; i < num_sizes; i++) { 6076 const size_t size = sizes[i]; 6077 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6078 char* const req_addr = align_up(mapping1, alignment); 6079 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6080 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6081 size, alignment, p2i(req_addr), p2i(p), 6082 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6083 if (p != NULL) { 6084 assert(p == req_addr, "must be"); 6085 small_page_write(p, size); 6086 os::Linux::release_memory_special_huge_tlbfs(p, size); 6087 } 6088 } 6089 } 6090 6091 // Case 3 6092 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6093 test_log("size align req_addr result"); 6094 6095 for (int i = 0; i < num_sizes; i++) { 6096 const size_t size = sizes[i]; 6097 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6098 char* const req_addr = align_up(mapping2, alignment); 6099 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6100 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6101 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6102 // as the area around req_addr contains already existing mappings, the API should always 6103 // return NULL (as per contract, it cannot return another address) 6104 assert(p == NULL, "must be"); 6105 } 6106 } 6107 6108 ::munmap(mapping2, mapping_size); 6109 6110 } 6111 6112 static void test_reserve_memory_special_huge_tlbfs() { 6113 if (!UseHugeTLBFS) { 6114 return; 6115 } 6116 6117 test_reserve_memory_special_huge_tlbfs_only(); 6118 test_reserve_memory_special_huge_tlbfs_mixed(); 6119 } 6120 6121 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6122 if (!UseSHM) { 6123 return; 6124 } 6125 6126 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6127 6128 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6129 6130 if (addr != NULL) { 6131 assert(is_aligned(addr, alignment), "Check"); 6132 assert(is_aligned(addr, os::large_page_size()), "Check"); 6133 6134 small_page_write(addr, size); 6135 6136 os::Linux::release_memory_special_shm(addr, size); 6137 } 6138 } 6139 6140 static void test_reserve_memory_special_shm() { 6141 size_t lp = os::large_page_size(); 6142 size_t ag = os::vm_allocation_granularity(); 6143 6144 for (size_t size = ag; size < lp * 3; size += ag) { 6145 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6146 test_reserve_memory_special_shm(size, alignment); 6147 } 6148 } 6149 } 6150 6151 static void test() { 6152 test_reserve_memory_special_huge_tlbfs(); 6153 test_reserve_memory_special_shm(); 6154 } 6155 }; 6156 6157 void TestReserveMemorySpecial_test() { 6158 TestReserveMemorySpecial::test(); 6159 } 6160 6161 #endif