1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
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 "mozilla/AvailableMemoryTracker.h"
8
9 #if defined(XP_WIN)
10 # include "mozilla/WindowsVersion.h"
11 #endif
12
13 #include "nsIObserver.h"
14 #include "nsIObserverService.h"
15 #include "nsIRunnable.h"
16 #include "nsISupports.h"
17 #include "nsThreadUtils.h"
18 #include "nsXULAppAPI.h"
19
20 #include "mozilla/Mutex.h"
21 #include "mozilla/ResultExtensions.h"
22 #include "mozilla/Services.h"
23
24 #if defined(MOZ_MEMORY)
25 # include "mozmemory.h"
26 #endif // MOZ_MEMORY
27
28 using namespace mozilla;
29
30 namespace {
31
32 #if defined(XP_WIN)
33
34 # if (NTDDI_VERSION < NTDDI_WINBLUE) || \
35 (NTDDI_VERSION == NTDDI_WINBLUE && !defined(WINBLUE_KBSPRING14))
36 // Definitions for heap optimization that require the Windows SDK to target the
37 // Windows 8.1 Update
38 static const HEAP_INFORMATION_CLASS HeapOptimizeResources =
39 static_cast<HEAP_INFORMATION_CLASS>(3);
40
41 static const DWORD HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION = 1;
42
43 typedef struct _HEAP_OPTIMIZE_RESOURCES_INFORMATION {
44 DWORD Version;
45 DWORD Flags;
46 } HEAP_OPTIMIZE_RESOURCES_INFORMATION, *PHEAP_OPTIMIZE_RESOURCES_INFORMATION;
47 # endif
48
49 Atomic<uint32_t, MemoryOrdering::Relaxed> sNumLowPhysicalMemEvents;
50
LowMemoryEventsPhysicalDistinguishedAmount()51 static int64_t LowMemoryEventsPhysicalDistinguishedAmount() {
52 return sNumLowPhysicalMemEvents;
53 }
54
55 class LowEventsReporter final : public nsIMemoryReporter {
~LowEventsReporter()56 ~LowEventsReporter() {}
57
58 public:
59 NS_DECL_ISUPPORTS
60
CollectReports(nsIHandleReportCallback * aHandleReport,nsISupports * aData,bool aAnonymize)61 NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
62 nsISupports* aData, bool aAnonymize) override {
63 // clang-format off
64 MOZ_COLLECT_REPORT(
65 "low-memory-events/physical", KIND_OTHER, UNITS_COUNT_CUMULATIVE,
66 LowMemoryEventsPhysicalDistinguishedAmount(),
67 "Number of low-physical-memory events fired since startup. We fire such an "
68 "event when a windows low memory resource notification is signaled. The "
69 "machine will start to page if it runs out of physical memory. This may "
70 "cause it to run slowly, but it shouldn't cause it to crash.");
71 // clang-format on
72
73 return NS_OK;
74 }
75 };
76
77 NS_IMPL_ISUPPORTS(LowEventsReporter, nsIMemoryReporter)
78
79 #endif // defined(XP_WIN)
80
81 /**
82 * This runnable is executed in response to a memory-pressure event; we spin
83 * the event-loop when receiving the memory-pressure event in the hope that
84 * other observers will synchronously free some memory that we'll be able to
85 * purge here.
86 */
87 class nsJemallocFreeDirtyPagesRunnable final : public Runnable {
88 ~nsJemallocFreeDirtyPagesRunnable() = default;
89
90 #if defined(XP_WIN)
91 void OptimizeSystemHeap();
92 #endif
93
94 public:
95 NS_DECL_NSIRUNNABLE
96
nsJemallocFreeDirtyPagesRunnable()97 nsJemallocFreeDirtyPagesRunnable()
98 : Runnable("nsJemallocFreeDirtyPagesRunnable") {}
99 };
100
101 NS_IMETHODIMP
Run()102 nsJemallocFreeDirtyPagesRunnable::Run() {
103 MOZ_ASSERT(NS_IsMainThread());
104
105 #if defined(MOZ_MEMORY)
106 jemalloc_free_dirty_pages();
107 #endif
108
109 #if defined(XP_WIN)
110 OptimizeSystemHeap();
111 #endif
112
113 return NS_OK;
114 }
115
116 #if defined(XP_WIN)
OptimizeSystemHeap()117 void nsJemallocFreeDirtyPagesRunnable::OptimizeSystemHeap() {
118 // HeapSetInformation exists prior to Windows 8.1, but the
119 // HeapOptimizeResources information class does not.
120 if (IsWin8Point1OrLater()) {
121 HEAP_OPTIMIZE_RESOURCES_INFORMATION heapOptInfo = {
122 HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION};
123
124 ::HeapSetInformation(nullptr, HeapOptimizeResources, &heapOptInfo,
125 sizeof(heapOptInfo));
126 }
127 }
128 #endif // defined(XP_WIN)
129
130 /**
131 * The memory pressure watcher is used for listening to memory-pressure events
132 * and reacting upon them. We use one instance per process currently only for
133 * cleaning up dirty unused pages held by jemalloc.
134 */
135 class nsMemoryPressureWatcher final : public nsIObserver {
136 ~nsMemoryPressureWatcher() = default;
137
138 public:
139 NS_DECL_ISUPPORTS
140 NS_DECL_NSIOBSERVER
141
142 void Init();
143 };
144
NS_IMPL_ISUPPORTS(nsMemoryPressureWatcher,nsIObserver)145 NS_IMPL_ISUPPORTS(nsMemoryPressureWatcher, nsIObserver)
146
147 /**
148 * Initialize and subscribe to the memory-pressure events. We subscribe to the
149 * observer service in this method and not in the constructor because we need
150 * to hold a strong reference to 'this' before calling the observer service.
151 */
152 void nsMemoryPressureWatcher::Init() {
153 nsCOMPtr<nsIObserverService> os = services::GetObserverService();
154
155 if (os) {
156 os->AddObserver(this, "memory-pressure", /* ownsWeak */ false);
157 }
158 }
159
160 /**
161 * Reacts to all types of memory-pressure events, launches a runnable to
162 * free dirty pages held by jemalloc.
163 */
164 NS_IMETHODIMP
Observe(nsISupports * aSubject,const char * aTopic,const char16_t * aData)165 nsMemoryPressureWatcher::Observe(nsISupports* aSubject, const char* aTopic,
166 const char16_t* aData) {
167 MOZ_ASSERT(!strcmp(aTopic, "memory-pressure"), "Unknown topic");
168
169 nsCOMPtr<nsIRunnable> runnable = new nsJemallocFreeDirtyPagesRunnable();
170
171 NS_DispatchToMainThread(runnable);
172
173 return NS_OK;
174 }
175
176 } // namespace
177
178 namespace mozilla {
179 namespace AvailableMemoryTracker {
180
Init()181 void Init() {
182 // The watchers are held alive by the observer service.
183 RefPtr<nsMemoryPressureWatcher> watcher = new nsMemoryPressureWatcher();
184 watcher->Init();
185
186 #if defined(XP_WIN)
187 RegisterLowMemoryEventsPhysicalDistinguishedAmount(
188 LowMemoryEventsPhysicalDistinguishedAmount);
189 #endif // defined(XP_WIN)
190 }
191
192 } // namespace AvailableMemoryTracker
193 } // namespace mozilla
194