Line data Source code
1 : // Copyright 2015 the V8 project 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 "src/heap/memory-reducer.h"
6 :
7 : #include "src/flags.h"
8 : #include "src/heap/gc-tracer.h"
9 : #include "src/heap/heap-inl.h"
10 : #include "src/utils.h"
11 : #include "src/v8.h"
12 :
13 : namespace v8 {
14 : namespace internal {
15 :
16 : const int MemoryReducer::kLongDelayMs = 8000;
17 : const int MemoryReducer::kShortDelayMs = 500;
18 : const int MemoryReducer::kWatchdogDelayMs = 100000;
19 : const int MemoryReducer::kMaxNumberOfGCs = 3;
20 : const double MemoryReducer::kCommittedMemoryFactor = 1.1;
21 : const size_t MemoryReducer::kCommittedMemoryDelta = 10 * MB;
22 :
23 405 : MemoryReducer::TimerTask::TimerTask(MemoryReducer* memory_reducer)
24 : : CancelableTask(memory_reducer->heap()->isolate()),
25 405 : memory_reducer_(memory_reducer) {}
26 :
27 :
28 9 : void MemoryReducer::TimerTask::RunInternal() {
29 27 : Heap* heap = memory_reducer_->heap();
30 : Event event;
31 9 : double time_ms = heap->MonotonicallyIncreasingTimeInMs();
32 : heap->tracer()->SampleAllocation(time_ms, heap->NewSpaceAllocationCounter(),
33 9 : heap->OldGenerationAllocationCounter());
34 9 : bool low_allocation_rate = heap->HasLowAllocationRate();
35 9 : bool optimize_for_memory = heap->ShouldOptimizeForMemoryUsage();
36 9 : if (FLAG_trace_gc_verbose) {
37 : heap->isolate()->PrintWithTimestamp(
38 : "Memory reducer: %s, %s\n",
39 : low_allocation_rate ? "low alloc" : "high alloc",
40 0 : optimize_for_memory ? "background" : "foreground");
41 : }
42 9 : event.type = kTimer;
43 9 : event.time_ms = time_ms;
44 : // The memory reducer will start incremental markig if
45 : // 1) mutator is likely idle: js call rate is low and allocation rate is low.
46 : // 2) mutator is in background: optimize for memory flag is set.
47 : event.should_start_incremental_gc =
48 9 : low_allocation_rate || optimize_for_memory;
49 : event.can_start_incremental_gc =
50 13 : heap->incremental_marking()->IsStopped() &&
51 4 : (heap->incremental_marking()->CanBeActivated() || optimize_for_memory);
52 9 : event.committed_memory = heap->CommittedOldGenerationMemory();
53 9 : memory_reducer_->NotifyTimer(event);
54 9 : }
55 :
56 :
57 18 : void MemoryReducer::NotifyTimer(const Event& event) {
58 : DCHECK_EQ(kTimer, event.type);
59 : DCHECK_EQ(kWait, state_.action);
60 9 : state_ = Step(state_, event);
61 9 : if (state_.action == kRun) {
62 : DCHECK(heap()->incremental_marking()->IsStopped());
63 : DCHECK(FLAG_incremental_marking);
64 0 : if (FLAG_trace_gc_verbose) {
65 : heap()->isolate()->PrintWithTimestamp("Memory reducer: started GC #%d\n",
66 0 : state_.started_gcs);
67 : }
68 : heap()->StartIdleIncrementalMarking(
69 : GarbageCollectionReason::kMemoryReducer,
70 0 : kGCCallbackFlagCollectAllExternalMemory);
71 9 : } else if (state_.action == kWait) {
72 23 : if (!heap()->incremental_marking()->IsStopped() &&
73 5 : heap()->ShouldOptimizeForMemoryUsage()) {
74 : // Make progress with pending incremental marking if memory usage has
75 : // higher priority than latency. This is important for background tabs
76 : // that do not send idle notifications.
77 : const int kIncrementalMarkingDelayMs = 500;
78 0 : double deadline = heap()->MonotonicallyIncreasingTimeInMs() +
79 0 : kIncrementalMarkingDelayMs;
80 : heap()->incremental_marking()->AdvanceIncrementalMarking(
81 : deadline, IncrementalMarking::NO_GC_VIA_STACK_GUARD,
82 0 : StepOrigin::kTask);
83 : heap()->FinalizeIncrementalMarkingIfComplete(
84 0 : GarbageCollectionReason::kFinalizeMarkingViaTask);
85 : }
86 : // Re-schedule the timer.
87 9 : ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
88 9 : if (FLAG_trace_gc_verbose) {
89 : heap()->isolate()->PrintWithTimestamp(
90 : "Memory reducer: waiting for %.f ms\n",
91 0 : state_.next_gc_start_ms - event.time_ms);
92 : }
93 : }
94 9 : }
95 :
96 :
97 56800 : void MemoryReducer::NotifyMarkCompact(const Event& event) {
98 : DCHECK_EQ(kMarkCompact, event.type);
99 56800 : Action old_action = state_.action;
100 56800 : state_ = Step(state_, event);
101 56800 : if (old_action != kWait && state_.action == kWait) {
102 : // If we are transitioning to the WAIT state, start the timer.
103 217 : ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
104 : }
105 56800 : if (old_action == kRun) {
106 0 : if (FLAG_trace_gc_verbose) {
107 : heap()->isolate()->PrintWithTimestamp(
108 : "Memory reducer: finished GC #%d (%s)\n", state_.started_gcs,
109 0 : state_.action == kWait ? "will do more" : "done");
110 : }
111 : }
112 56800 : }
113 :
114 1387 : void MemoryReducer::NotifyPossibleGarbage(const Event& event) {
115 : DCHECK_EQ(kPossibleGarbage, event.type);
116 1387 : Action old_action = state_.action;
117 1387 : state_ = Step(state_, event);
118 1387 : if (old_action != kWait && state_.action == kWait) {
119 : // If we are transitioning to the WAIT state, start the timer.
120 179 : ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
121 : }
122 1387 : }
123 :
124 :
125 0 : bool MemoryReducer::WatchdogGC(const State& state, const Event& event) {
126 15 : return state.last_gc_time_ms != 0 &&
127 7 : event.time_ms > state.last_gc_time_ms + kWatchdogDelayMs;
128 : }
129 :
130 :
131 : // For specification of this function see the comment for MemoryReducer class.
132 58226 : MemoryReducer::State MemoryReducer::Step(const State& state,
133 : const Event& event) {
134 58226 : if (!FLAG_incremental_marking || !FLAG_memory_reducer) {
135 328 : return State(kDone, 0, 0, state.last_gc_time_ms, 0);
136 : }
137 57898 : switch (state.action) {
138 : case kDone:
139 55652 : if (event.type == kTimer) {
140 3 : return state;
141 55649 : } else if (event.type == kMarkCompact) {
142 110938 : if (event.committed_memory <
143 55469 : Max(static_cast<size_t>(state.committed_memory_at_last_run *
144 : kCommittedMemoryFactor),
145 110938 : state.committed_memory_at_last_run + kCommittedMemoryDelta)) {
146 55249 : return state;
147 : } else {
148 : return State(kWait, 0, event.time_ms + kLongDelayMs,
149 : event.type == kMarkCompact ? event.time_ms
150 : : state.last_gc_time_ms,
151 220 : 0);
152 : }
153 : } else {
154 : DCHECK_EQ(kPossibleGarbage, event.type);
155 : return State(
156 : kWait, 0, event.time_ms + kLongDelayMs,
157 : event.type == kMarkCompact ? event.time_ms : state.last_gc_time_ms,
158 180 : 0);
159 : }
160 : case kWait:
161 2238 : switch (event.type) {
162 : case kPossibleGarbage:
163 1204 : return state;
164 : case kTimer:
165 19 : if (state.started_gcs >= kMaxNumberOfGCs) {
166 : return State(kDone, kMaxNumberOfGCs, 0.0, state.last_gc_time_ms,
167 3 : event.committed_memory);
168 32 : } else if (event.can_start_incremental_gc &&
169 8 : (event.should_start_incremental_gc ||
170 : WatchdogGC(state, event))) {
171 3 : if (state.next_gc_start_ms <= event.time_ms) {
172 : return State(kRun, state.started_gcs + 1, 0.0,
173 2 : state.last_gc_time_ms, 0);
174 : } else {
175 1 : return state;
176 : }
177 : } else {
178 : return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs,
179 13 : state.last_gc_time_ms, 0);
180 : }
181 : case kMarkCompact:
182 : return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs,
183 1015 : event.time_ms, 0);
184 : }
185 : case kRun:
186 8 : if (event.type != kMarkCompact) {
187 4 : return state;
188 : } else {
189 4 : if (state.started_gcs < kMaxNumberOfGCs &&
190 2 : (event.next_gc_likely_to_collect_more || state.started_gcs == 1)) {
191 : return State(kWait, state.started_gcs, event.time_ms + kShortDelayMs,
192 2 : event.time_ms, 0);
193 : } else {
194 : return State(kDone, kMaxNumberOfGCs, 0.0, event.time_ms,
195 2 : event.committed_memory);
196 : }
197 : }
198 : }
199 0 : UNREACHABLE();
200 : }
201 :
202 :
203 405 : void MemoryReducer::ScheduleTimer(double time_ms, double delay_ms) {
204 : DCHECK_LT(0, delay_ms);
205 : // Leave some room for precision error in task scheduler.
206 : const double kSlackMs = 100;
207 : v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(heap()->isolate());
208 405 : auto timer_task = new MemoryReducer::TimerTask(this);
209 405 : V8::GetCurrentPlatform()->CallDelayedOnForegroundThread(
210 405 : isolate, timer_task, (delay_ms + kSlackMs) / 1000.0);
211 405 : }
212 :
213 53365 : void MemoryReducer::TearDown() { state_ = State(kDone, 0, 0, 0.0, 0); }
214 :
215 : } // namespace internal
216 : } // namespace v8
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