/* * Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "logging/log.hpp" #include "memory/allocation.inline.hpp" #include "prims/jvm.h" #include "runtime/arguments.hpp" #include "runtime/java.hpp" #include "runtime/mutex.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/orderAccess.inline.hpp" #include "runtime/os.hpp" #include "runtime/perfData.hpp" #include "runtime/perfMemory.hpp" #include "runtime/safepoint.hpp" #include "runtime/statSampler.hpp" #include "utilities/align.hpp" #include "utilities/globalDefinitions.hpp" // Prefix of performance data file. const char PERFDATA_NAME[] = "hsperfdata"; // Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating // character will be included in the sizeof(PERFDATA_NAME) operation. static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) + UINT_CHARS + 1; char* PerfMemory::_start = NULL; char* PerfMemory::_end = NULL; char* PerfMemory::_top = NULL; size_t PerfMemory::_capacity = 0; jint PerfMemory::_initialized = false; PerfDataPrologue* PerfMemory::_prologue = NULL; void perfMemory_init() { if (!UsePerfData) return; PerfMemory::initialize(); } void perfMemory_exit() { if (!UsePerfData) return; if (!PerfMemory::is_initialized()) return; // Only destroy PerfData objects if we're at a safepoint and the // StatSampler is not active. Otherwise, we risk removing PerfData // objects that are currently being used by running JavaThreads // or the StatSampler. This method is invoked while we are not at // a safepoint during a VM abort so leaving the PerfData objects // around may also help diagnose the failure. In rare cases, // PerfData objects are used in parallel with a safepoint. See // the work around in PerfDataManager::destroy(). // if (SafepointSynchronize::is_at_safepoint() && !StatSampler::is_active()) { PerfDataManager::destroy(); } // Remove the persistent external resources, if any. This method // does not unmap or invalidate any virtual memory allocated during // initialization. // PerfMemory::destroy(); } void PerfMemory::initialize() { if (_prologue != NULL) // initialization already performed return; size_t capacity = align_up(PerfDataMemorySize, os::vm_allocation_granularity()); log_debug(perf, memops)("PerfDataMemorySize = " SIZE_FORMAT "," " os::vm_allocation_granularity = %d," " adjusted size = " SIZE_FORMAT "\n", PerfDataMemorySize, os::vm_allocation_granularity(), capacity); // allocate PerfData memory region create_memory_region(capacity); if (_start == NULL) { // the PerfMemory region could not be created as desired. Rather // than terminating the JVM, we revert to creating the instrumentation // on the C heap. When running in this mode, external monitoring // clients cannot attach to and monitor this JVM. // // the warning is issued only in debug mode in order to avoid // additional output to the stdout or stderr output streams. // if (PrintMiscellaneous && Verbose) { warning("Could not create PerfData Memory region, reverting to malloc"); } _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue, mtInternal); } else { // the PerfMemory region was created as expected. log_debug(perf, memops)("PerfMemory created: address = " INTPTR_FORMAT "," " size = " SIZE_FORMAT "\n", p2i(_start), _capacity); _prologue = (PerfDataPrologue *)_start; _end = _start + _capacity; _top = _start + sizeof(PerfDataPrologue); } assert(_prologue != NULL, "prologue pointer must be initialized"); #ifdef VM_LITTLE_ENDIAN _prologue->magic = (jint)0xc0c0feca; _prologue->byte_order = PERFDATA_LITTLE_ENDIAN; #else _prologue->magic = (jint)0xcafec0c0; _prologue->byte_order = PERFDATA_BIG_ENDIAN; #endif _prologue->major_version = PERFDATA_MAJOR_VERSION; _prologue->minor_version = PERFDATA_MINOR_VERSION; _prologue->accessible = 0; _prologue->entry_offset = sizeof(PerfDataPrologue); _prologue->num_entries = 0; _prologue->used = 0; _prologue->overflow = 0; _prologue->mod_time_stamp = 0; OrderAccess::release_store(&_initialized, 1); } void PerfMemory::destroy() { if (_prologue == NULL) return; if (_start != NULL && _prologue->overflow != 0) { // This state indicates that the contiguous memory region exists and // that it wasn't large enough to hold all the counters. In this case, // we output a warning message to the user on exit if the -XX:+Verbose // flag is set (a debug only flag). External monitoring tools can detect // this condition by monitoring the _prologue->overflow word. // // There are two tunables that can help resolve this issue: // - increase the size of the PerfMemory with -XX:PerfDataMemorySize= // - decrease the maximum string constant length with // -XX:PerfMaxStringConstLength= // if (PrintMiscellaneous && Verbose) { warning("PerfMemory Overflow Occurred.\n" "\tCapacity = " SIZE_FORMAT " bytes" " Used = " SIZE_FORMAT " bytes" " Overflow = " INT32_FORMAT " bytes" "\n\tUse -XX:PerfDataMemorySize= to specify larger size.", PerfMemory::capacity(), PerfMemory::used(), _prologue->overflow); } } if (_start != NULL) { // this state indicates that the contiguous memory region was successfully // and that persistent resources may need to be cleaned up. This is // expected to be the typical condition. // delete_memory_region(); } _start = NULL; _end = NULL; _top = NULL; _prologue = NULL; _capacity = 0; } // allocate an aligned block of memory from the PerfData memory // region. This method assumes that the PerfData memory region // was aligned on a double word boundary when created. // char* PerfMemory::alloc(size_t size) { if (!UsePerfData) return NULL; MutexLocker ml(PerfDataMemAlloc_lock); assert(_prologue != NULL, "called before initialization"); // check that there is enough memory for this request if ((_top + size) >= _end) { _prologue->overflow += (jint)size; return NULL; } char* result = _top; _top += size; assert(contains(result), "PerfData memory pointer out of range"); _prologue->used = (jint)used(); _prologue->num_entries = _prologue->num_entries + 1; return result; } void PerfMemory::mark_updated() { if (!UsePerfData) return; _prologue->mod_time_stamp = os::elapsed_counter(); } // Returns the complete path including the file name of performance data file. // Caller is expected to release the allocated memory. char* PerfMemory::get_perfdata_file_path() { char* dest_file = NULL; if (PerfDataSaveFile != NULL) { // dest_file_name stores the validated file name if file_name // contains %p which will be replaced by pid. dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN, mtInternal); if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile), dest_file, JVM_MAXPATHLEN)) { FREE_C_HEAP_ARRAY(char, dest_file); if (PrintMiscellaneous && Verbose) { warning("Invalid performance data file path name specified, "\ "fall back to a default name"); } } else { return dest_file; } } // create the name of the file for retaining the instrumentation memory. dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN, mtInternal); jio_snprintf(dest_file, PERFDATA_FILENAME_LEN, "%s_%d", PERFDATA_NAME, os::current_process_id()); return dest_file; }