/*

 * Copyright (c) 2001, 2018, 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 "jvm.h"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "runtime/arguments.hpp"

#include "runtime/java.hpp"

#include "runtime/mutex.hpp"

#include "runtime/mutexLocker.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;

int                      PerfMemory::_initialized = false;

PerfDataPrologue*        PerfMemory::_prologue = NULL;

bool                     PerfMemory::_destroyed = false;

void perfMemory_init() {

  if (!UsePerfData) return;

  PerfMemory::initialize();

}

void perfMemory_exit() {

  if (!UsePerfData) return;

  if (!PerfMemory::is_usable()) 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 (is_initialized())

    // 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,

                          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,

                            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;

  Atomic::release_store(&_initialized, 1);

}

void PerfMemory::destroy() {

  if (!is_usable()) 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=<n>

    //   - decrease the maximum string constant length with

    //     -XX:PerfMaxStringConstLength=<n>

    //

    if (PrintMiscellaneous && Verbose) {

      warning("PerfMemory Overflow Occurred.\n"

              "\tCapacity = " SIZE_FORMAT " bytes"

              "  Used = " SIZE_FORMAT " bytes"

              "  Overflow = " INT32_FORMAT " bytes"

              "\n\tUse -XX:PerfDataMemorySize=<size> 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();

  }

  _destroyed = true;

}

// 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(is_usable(), "called before init or after destroy");

  // 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;

  assert(is_usable(), "called before init or after destroy");

  _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;

}

bool PerfMemory::is_initialized() {

  return Atomic::load_acquire(&_initialized) != 0;

}