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 : #ifndef V8_HEAP_SCAVENGE_JOB_H_
6 : #define V8_HEAP_SCAVENGE_JOB_H_
7 :
8 : #include "src/cancelable-task.h"
9 : #include "src/globals.h"
10 : #include "src/heap/gc-tracer.h"
11 :
12 : namespace v8 {
13 : namespace internal {
14 :
15 : class Heap;
16 : class Isolate;
17 :
18 :
19 : // This class posts idle tasks and performs scavenges in the idle tasks.
20 : class V8_EXPORT_PRIVATE ScavengeJob {
21 : public:
22 18246 : class IdleTask : public CancelableIdleTask {
23 : public:
24 : explicit IdleTask(Isolate* isolate, ScavengeJob* job)
25 9123 : : CancelableIdleTask(isolate), job_(job) {}
26 : // CancelableIdleTask overrides.
27 : void RunInternal(double deadline_in_seconds) override;
28 :
29 : private:
30 : ScavengeJob* job_;
31 : };
32 :
33 : ScavengeJob()
34 : : idle_task_pending_(false),
35 : idle_task_rescheduled_(false),
36 60782 : bytes_allocated_since_the_last_task_(0) {}
37 :
38 : // Posts an idle task if the cumulative bytes allocated since the last
39 : // idle task exceed kBytesAllocatedBeforeNextIdleTask.
40 : void ScheduleIdleTaskIfNeeded(Heap* heap, int bytes_allocated);
41 :
42 : // Posts an idle task ignoring the bytes allocated, but makes sure
43 : // that the new idle task cannot reschedule again.
44 : // This prevents infinite rescheduling.
45 : void RescheduleIdleTask(Heap* heap);
46 :
47 : bool IdleTaskPending() { return idle_task_pending_; }
48 9082 : void NotifyIdleTask() { idle_task_pending_ = false; }
49 : bool IdleTaskRescheduled() { return idle_task_rescheduled_; }
50 :
51 : static bool ReachedIdleAllocationLimit(double scavenge_speed_in_bytes_per_ms,
52 : size_t new_space_size,
53 : size_t new_space_capacity);
54 :
55 : static bool EnoughIdleTimeForScavenge(double idle_time_ms,
56 : double scavenge_speed_in_bytes_per_ms,
57 : size_t new_space_size);
58 :
59 : // If we haven't recorded any scavenger events yet, we use a conservative
60 : // lower bound for the scavenger speed.
61 : static const int kInitialScavengeSpeedInBytesPerMs = 256 * KB;
62 : // Estimate of the average idle time that an idle task gets.
63 : static const int kAverageIdleTimeMs = 5;
64 : // The number of bytes to be allocated in new space before the next idle
65 : // task is posted.
66 : static const size_t kBytesAllocatedBeforeNextIdleTask = 512 * KB;
67 : // The minimum size of allocated new space objects to trigger a scavenge.
68 : static const size_t kMinAllocationLimit = 512 * KB;
69 : // The allocation limit cannot exceed this fraction of the new space capacity.
70 : static const double kMaxAllocationLimitAsFractionOfNewSpace;
71 :
72 : private:
73 : void ScheduleIdleTask(Heap* heap);
74 : bool idle_task_pending_;
75 : bool idle_task_rescheduled_;
76 : int bytes_allocated_since_the_last_task_;
77 : };
78 : } // namespace internal
79 : } // namespace v8
80 :
81 : #endif // V8_HEAP_SCAVENGE_JOB_H_
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