xpcom/base/PHCManager.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "PHCManager.h"
   8
   9 #include "PHC.h"
  10 #include "mozilla/Literals.h"
  11 #include "mozilla/Preferences.h"
  12 #include "mozilla/StaticPrefs_memory.h"
  13 #include "mozilla/Telemetry.h"
  14 #include "prsystem.h"
  15
  16 namespace mozilla {
  17
  18 using namespace phc;
  19
  20 static const char kPHCEnabledPref[] = "memory.phc.enabled";
  21 static const char kPHCMinRamMBPref[] = "memory.phc.min_ram_mb";
  22 static const char kPHCAvgDelayFirst[] = "memory.phc.avg_delay.first";
  23 static const char kPHCAvgDelayNormal[] = "memory.phc.avg_delay.normal";
  24 static const char kPHCAvgDelayPageRuse[] = "memory.phc.avg_delay.page_reuse";
  25
  26 // True if PHC has ever been enabled for this process.
  27 static bool sWasPHCEnabled = false;
  28
  29 static void UpdatePHCState() {
  30   size_t mem_size = PR_GetPhysicalMemorySize() / (1_MiB);
  31   size_t min_mem_size = StaticPrefs::memory_phc_min_ram_mb();
  32
  33   // Only enable PHC if there are at least 8GB of ram.  Note that we use
  34   // 1000 bytes per kilobyte rather than 1024.  Some 8GB machines will have
  35   // slightly lower actual RAM available after some hardware devices
  36   // reserve some.
  37   if (StaticPrefs::memory_phc_enabled() && mem_size >= min_mem_size) {
  38     // Set PHC probablities before enabling PHC so that the first allocation
  39     // delay gets used.
  40     SetPHCProbabilities(StaticPrefs::memory_phc_avg_delay_first(),
  41                         StaticPrefs::memory_phc_avg_delay_normal(),
  42                         StaticPrefs::memory_phc_avg_delay_page_reuse());
  43
  44     SetPHCState(Enabled);
  45     sWasPHCEnabled = true;
  46   } else {
  47     SetPHCState(OnlyFree);
  48   }
  49 }
  50
  51 static void PrefChangeCallback(const char* aPrefName, void* aNull) {
  52   MOZ_ASSERT((0 == strcmp(aPrefName, kPHCEnabledPref)) ||
  53              (0 == strcmp(aPrefName, kPHCMinRamMBPref)) ||
  54              (0 == strcmp(aPrefName, kPHCAvgDelayFirst)) ||
  55              (0 == strcmp(aPrefName, kPHCAvgDelayNormal)) ||
  56              (0 == strcmp(aPrefName, kPHCAvgDelayPageRuse)));
  57
  58   UpdatePHCState();
  59 }
  60
  61 void InitPHCState() {
  62   Preferences::RegisterCallback(PrefChangeCallback, kPHCEnabledPref);
  63   Preferences::RegisterCallback(PrefChangeCallback, kPHCMinRamMBPref);
  64   Preferences::RegisterCallback(PrefChangeCallback, kPHCAvgDelayFirst);
  65   Preferences::RegisterCallback(PrefChangeCallback, kPHCAvgDelayNormal);
  66   Preferences::RegisterCallback(PrefChangeCallback, kPHCAvgDelayPageRuse);
  67   UpdatePHCState();
  68 }
  69
  70 void ReportPHCTelemetry() {
  71   if (!sWasPHCEnabled) {
  72     return;
  73   }
  74
  75   MemoryUsage usage;
  76   PHCMemoryUsage(usage);
  77
  78   Accumulate(Telemetry::MEMORY_PHC_SLOP, usage.mFragmentationBytes);
  79
  80   PHCStats stats;
  81   GetPHCStats(stats);
  82
  83   Accumulate(Telemetry::MEMORY_PHC_SLOTS_ALLOCATED, stats.mSlotsAllocated);
  84   Accumulate(Telemetry::MEMORY_PHC_SLOTS_FREED, stats.mSlotsFreed);
  85   // There are also slots that are unused (neither free nor allocated) they
  86   // can be calculated by knowing the total number of slots.
  87 }
  88
  89 };  // namespace mozilla