src/hotspot/share/memory/metaspaceCounters.cpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * version 2 for more details (a copy is included in the LICENSE file that
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#include "memory/metaspace.hpp"
#include "memory/metaspaceCounters.hpp"
#include "memory/metaspaceStats.hpp"
#include "memory/metaspaceUtils.hpp"
#include "memory/resourceArea.hpp"
#include "runtime/globals.hpp"
#include "runtime/perfData.hpp"
#include "utilities/exceptions.hpp"

class MetaspacePerfCounters {
  friend class VMStructs;
  PerfVariable*      _capacity;
  PerfVariable*      _used;
  PerfVariable*      _max_capacity;

  PerfVariable* create_variable(const char *ns, const char *name, size_t value, TRAPS) {
    const char *path = PerfDataManager::counter_name(ns, name);
    return PerfDataManager::create_variable(SUN_GC, path, PerfData::U_Bytes, value, THREAD);
  }

  void create_constant(const char *ns, const char *name, size_t value, TRAPS) {
    const char *path = PerfDataManager::counter_name(ns, name);
    PerfDataManager::create_constant(SUN_GC, path, PerfData::U_Bytes, value, THREAD);
  }

 public:
  MetaspacePerfCounters() : _capacity(nullptr), _used(nullptr), _max_capacity(nullptr) {}

  void initialize(const char* ns) {
    assert(_capacity == nullptr, "Only initialize once");
    EXCEPTION_MARK;
    ResourceMark rm;

    create_constant(ns, "minCapacity", 0, THREAD); // min_capacity makes little sense in the context of metaspace
    _capacity = create_variable(ns, "capacity", 0, THREAD);
    _max_capacity = create_variable(ns, "maxCapacity", 0, THREAD);
    _used = create_variable(ns, "used", 0, THREAD);
  }

  void update(const MetaspaceStats& stats) {
    _capacity->set_value(stats.committed());
    _max_capacity->set_value(stats.reserved());
    _used->set_value(stats.used());
  }
};

static MetaspacePerfCounters g_meta_space_perf_counters; // class + nonclass
static MetaspacePerfCounters g_class_space_perf_counters;

void MetaspaceCounters::initialize_performance_counters() {
  if (UsePerfData) {
    g_meta_space_perf_counters.initialize("metaspace");
    g_class_space_perf_counters.initialize("compressedclassspace");
    update_performance_counters();
  }
}

void MetaspaceCounters::update_performance_counters() {
  if (UsePerfData) {
    g_meta_space_perf_counters.update(MetaspaceUtils::get_combined_statistics());
    g_class_space_perf_counters.update(MetaspaceUtils::get_statistics(Metaspace::ClassType));
  }
}