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1 // Copyright 2016 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 #ifndef BLIMP_CLIENT_APP_BLIMP_DISCARDABLE_MEMORY_ALLOCATOR_H_ | |
6 #define BLIMP_CLIENT_APP_BLIMP_DISCARDABLE_MEMORY_ALLOCATOR_H_ | |
7 | |
8 #include <list> | |
9 #include <memory> | |
10 | |
11 #include "base/macros.h" | |
12 #include "base/memory/discardable_memory_allocator.h" | |
13 #include "base/synchronization/lock.h" | |
14 | |
15 namespace blimp { | |
16 namespace client { | |
17 | |
18 // TODO(khushalsagar): See if we can share this implementation with html_viewer. | |
19 // A discardable memory allocator which will unallocate chunks on new | |
20 // allocations or as old chunks are unlocked. | |
21 class BlimpDiscardableMemoryAllocator : | |
22 public base::DiscardableMemoryAllocator { | |
23 public: | |
24 BlimpDiscardableMemoryAllocator(); | |
25 explicit BlimpDiscardableMemoryAllocator(size_t desired_max_memory); | |
26 ~BlimpDiscardableMemoryAllocator() override; | |
27 | |
28 // Overridden from DiscardableMemoryAllocator: | |
29 std::unique_ptr<base::DiscardableMemory> AllocateLockedDiscardableMemory( | |
30 size_t size) override; | |
31 | |
32 private: | |
33 class DiscardableMemoryChunkImpl; | |
34 friend class DiscardableMemoryChunkImpl; | |
35 | |
36 typedef std::list<DiscardableMemoryChunkImpl*> MemoryChunkList; | |
37 | |
38 // Called by DiscardableMemoryChunkImpl when they are unlocked. This puts them | |
39 // at the end of the live_unlocked_chunks_ list and passes an iterator to | |
40 // their position in the unlocked chunk list. | |
41 MemoryChunkList::iterator NotifyUnlocked( | |
42 DiscardableMemoryChunkImpl* chunk); | |
43 | |
44 // Called by DiscardableMemoryChunkImpl when they are locked. This removes the | |
45 // passed in unlocked chunk list. | |
46 void NotifyLocked(MemoryChunkList::iterator it); | |
47 | |
48 // Called by DiscardableMemoryChunkImpl when it's destructed. It must be | |
49 // unlocked, by definition. | |
50 void NotifyDestructed(MemoryChunkList::iterator it); | |
51 | |
52 // Unallocate unlocked chunks if the total live memory is higher than the | |
53 // desired max memory. | |
54 void FreeUnlockedChunksIfNeeded(); | |
55 | |
56 // The amount of memory we can allocate before we try to free unlocked | |
57 // chunks. We can go over this amount if all callers keep their discardable | |
58 // chunks locked. | |
59 const size_t desired_max_memory_; | |
60 | |
61 // Protects all members below, since this class can be called on the main | |
62 // thread and impl side painting raster threads. | |
63 base::Lock lock_; | |
64 | |
65 // A count of the sum of memory. Used to trigger discarding the oldest | |
66 // memory. | |
67 size_t total_live_memory_; | |
68 | |
69 // The number of locked chunks. | |
70 int locked_chunks_; | |
71 | |
72 // A linked list of unlocked allocated chunks so that the tail is most | |
73 // recently accessed chunks. | |
74 MemoryChunkList live_unlocked_chunks_; | |
75 | |
76 DISALLOW_COPY_AND_ASSIGN(BlimpDiscardableMemoryAllocator); | |
77 }; | |
78 | |
79 } // namespace client | |
80 } // namespace blimp | |
81 | |
82 #endif // BLIMP_CLIENT_APP_BLIMP_DISCARDABLE_MEMORY_ALLOCATOR_H_ | |
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