base/memory/memory_pressure_monitor_mac.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/memory/memory_pressure_monitor_mac.h"
   6
   7 #include <dlfcn.h>
   8 #include <sys/sysctl.h>
   9
  10 #include "base/mac/mac_util.h"
  11
  12 namespace base {
  13 namespace mac {
  14
  15 MemoryPressureListener::MemoryPressureLevel
  16 MemoryPressureMonitor::MemoryPressureLevelForMacMemoryPressure(
  17     int mac_memory_pressure) {
  18   switch (mac_memory_pressure) {
  19     case DISPATCH_MEMORYPRESSURE_NORMAL:
  20       return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
  21     case DISPATCH_MEMORYPRESSURE_WARN:
  22       return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE;
  23     case DISPATCH_MEMORYPRESSURE_CRITICAL:
  24       return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL;
  25   }
  26   return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
  27 }
  28
  29 void MemoryPressureMonitor::NotifyMemoryPressureChanged(
  30     dispatch_source_s* event_source) {
  31   int mac_memory_pressure = dispatch_source_get_data(event_source);
  32   MemoryPressureListener::MemoryPressureLevel memory_pressure_level =
  33       MemoryPressureLevelForMacMemoryPressure(mac_memory_pressure);
  34   MemoryPressureListener::NotifyMemoryPressure(memory_pressure_level);
  35 }
  36
  37 MemoryPressureMonitor::MemoryPressureMonitor()
  38   : memory_level_event_source_(nullptr) {
  39   // _dispatch_source_type_memorypressure is not available prior to 10.9.
  40   dispatch_source_type_t dispatch_source_memorypressure =
  41       static_cast<dispatch_source_type_t>
  42           (dlsym(RTLD_NEXT, "_dispatch_source_type_memorypressure"));
  43   if (dispatch_source_memorypressure) {
  44     // The MemoryPressureListener doesn't want to know about transitions to
  45     // MEMORY_PRESSURE_LEVEL_NONE so don't watch for
  46     // DISPATCH_MEMORYPRESSURE_NORMAL notifications.
  47     memory_level_event_source_.reset(
  48         dispatch_source_create(dispatch_source_memorypressure, 0,
  49                                DISPATCH_MEMORYPRESSURE_WARN |
  50                                    DISPATCH_MEMORYPRESSURE_CRITICAL,
  51                                dispatch_get_global_queue(
  52                                    DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)));
  53
  54     dispatch_source_set_event_handler(memory_level_event_source_.get(), ^{
  55         NotifyMemoryPressureChanged(memory_level_event_source_.get());
  56     });
  57     dispatch_retain(memory_level_event_source_.get());
  58     dispatch_resume(memory_level_event_source_.get());
  59   }
  60 }
  61
  62 MemoryPressureMonitor::~MemoryPressureMonitor() {
  63 }
  64
  65 MemoryPressureListener::MemoryPressureLevel
  66 MemoryPressureMonitor::GetCurrentPressureLevel() const {
  67   if (base::mac::IsOSMountainLionOrEarlier()) {
  68     return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
  69   }
  70   int mac_memory_pressure;
  71   size_t length = sizeof(int);
  72   sysctlbyname("kern.memorystatus_vm_pressure_level", &mac_memory_pressure,
  73                &length, nullptr, 0);
  74   return MemoryPressureLevelForMacMemoryPressure(mac_memory_pressure);
  75 }
  76
  77 }  // namespace mac
  78 }  // namespace base