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