halcanary@google.com | 2c7c7ee | 2013-12-05 18:31:42 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2013 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "SkDiscardableMemoryPool.h" |
| 9 | #include "SkOnce.h" |
| 10 | |
| 11 | // Note: |
| 12 | // A PoolDiscardableMemory is memory that is counted in a pool. |
| 13 | // A DiscardableMemoryPool is a pool of PoolDiscardableMemorys. |
| 14 | |
| 15 | /** |
| 16 | * A SkPoolDiscardableMemory is a SkDiscardableMemory that relies on |
| 17 | * a SkDiscardableMemoryPool object to manage the memory. |
| 18 | */ |
| 19 | class SkPoolDiscardableMemory : public SkDiscardableMemory { |
| 20 | public: |
| 21 | SkPoolDiscardableMemory(SkDiscardableMemoryPool* pool, |
| 22 | void* pointer, size_t bytes); |
| 23 | virtual ~SkPoolDiscardableMemory(); |
| 24 | virtual bool lock() SK_OVERRIDE; |
| 25 | virtual void* data() SK_OVERRIDE; |
| 26 | virtual void unlock() SK_OVERRIDE; |
| 27 | friend class SkDiscardableMemoryPool; |
| 28 | private: |
| 29 | SK_DECLARE_INTERNAL_LLIST_INTERFACE(SkPoolDiscardableMemory); |
| 30 | SkDiscardableMemoryPool* const fPool; |
| 31 | bool fLocked; |
| 32 | void* fPointer; |
| 33 | const size_t fBytes; |
| 34 | }; |
| 35 | |
| 36 | SkPoolDiscardableMemory::SkPoolDiscardableMemory(SkDiscardableMemoryPool* pool, |
| 37 | void* pointer, |
| 38 | size_t bytes) |
| 39 | : fPool(pool) |
| 40 | , fLocked(true) |
| 41 | , fPointer(pointer) |
| 42 | , fBytes(bytes) { |
| 43 | SkASSERT(fPool != NULL); |
| 44 | SkASSERT(fPointer != NULL); |
| 45 | SkASSERT(fBytes > 0); |
| 46 | fPool->ref(); |
| 47 | } |
| 48 | |
| 49 | SkPoolDiscardableMemory::~SkPoolDiscardableMemory() { |
reed@google.com | 1d0654f | 2013-12-12 22:37:32 +0000 | [diff] [blame^] | 50 | SkASSERT(!fLocked); // contract for SkDiscardableMemory |
halcanary@google.com | 2c7c7ee | 2013-12-05 18:31:42 +0000 | [diff] [blame] | 51 | fPool->free(this); |
| 52 | fPool->unref(); |
| 53 | } |
| 54 | |
| 55 | bool SkPoolDiscardableMemory::lock() { |
reed@google.com | 1d0654f | 2013-12-12 22:37:32 +0000 | [diff] [blame^] | 56 | SkASSERT(!fLocked); // contract for SkDiscardableMemory |
halcanary@google.com | 2c7c7ee | 2013-12-05 18:31:42 +0000 | [diff] [blame] | 57 | return fPool->lock(this); |
| 58 | } |
| 59 | |
| 60 | void* SkPoolDiscardableMemory::data() { |
reed@google.com | 1d0654f | 2013-12-12 22:37:32 +0000 | [diff] [blame^] | 61 | SkASSERT(fLocked); // contract for SkDiscardableMemory |
| 62 | return fPointer; |
halcanary@google.com | 2c7c7ee | 2013-12-05 18:31:42 +0000 | [diff] [blame] | 63 | } |
| 64 | |
| 65 | void SkPoolDiscardableMemory::unlock() { |
reed@google.com | 1d0654f | 2013-12-12 22:37:32 +0000 | [diff] [blame^] | 66 | SkASSERT(fLocked); // contract for SkDiscardableMemory |
halcanary@google.com | 2c7c7ee | 2013-12-05 18:31:42 +0000 | [diff] [blame] | 67 | fPool->unlock(this); |
| 68 | } |
| 69 | |
| 70 | //////////////////////////////////////////////////////////////////////////////// |
| 71 | |
| 72 | SkDiscardableMemoryPool::SkDiscardableMemoryPool(size_t budget, |
| 73 | SkBaseMutex* mutex) |
| 74 | : fMutex(mutex) |
| 75 | , fBudget(budget) |
| 76 | , fUsed(0) { |
| 77 | #if LAZY_CACHE_STATS |
| 78 | fCacheHits = 0; |
| 79 | fCacheMisses = 0; |
| 80 | #endif // LAZY_CACHE_STATS |
| 81 | } |
| 82 | SkDiscardableMemoryPool::~SkDiscardableMemoryPool() { |
| 83 | // SkPoolDiscardableMemory objects that belong to this pool are |
| 84 | // always deleted before deleting this pool since each one has a |
| 85 | // ref to the pool. |
| 86 | SkASSERT(fList.isEmpty()); |
| 87 | } |
| 88 | |
| 89 | void SkDiscardableMemoryPool::dumpDownTo(size_t budget) { |
| 90 | // assert((NULL = fMutex) || fMutex->isLocked()); |
| 91 | // TODO(halcanary) implement bool fMutex::isLocked(). |
| 92 | // WARNING: only call this function after aquiring lock. |
| 93 | if (fUsed <= budget) { |
| 94 | return; |
| 95 | } |
| 96 | typedef SkTInternalLList<SkPoolDiscardableMemory>::Iter Iter; |
| 97 | Iter iter; |
| 98 | SkPoolDiscardableMemory* cur = iter.init(fList, Iter::kTail_IterStart); |
| 99 | while ((fUsed > budget) && (NULL != cur)) { |
| 100 | if (!cur->fLocked) { |
| 101 | SkPoolDiscardableMemory* dm = cur; |
| 102 | SkASSERT(dm->fPointer != NULL); |
| 103 | sk_free(dm->fPointer); |
| 104 | dm->fPointer = NULL; |
| 105 | SkASSERT(fUsed >= dm->fBytes); |
| 106 | fUsed -= dm->fBytes; |
| 107 | cur = iter.prev(); |
| 108 | // Purged DMs are taken out of the list. This saves times |
| 109 | // looking them up. Purged DMs are NOT deleted. |
| 110 | fList.remove(dm); |
| 111 | } else { |
| 112 | cur = iter.prev(); |
| 113 | } |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | SkDiscardableMemory* SkDiscardableMemoryPool::create(size_t bytes) { |
| 118 | void* addr = sk_malloc_flags(bytes, 0); |
| 119 | if (NULL == addr) { |
| 120 | return NULL; |
| 121 | } |
| 122 | SkPoolDiscardableMemory* dm = SkNEW_ARGS(SkPoolDiscardableMemory, |
| 123 | (this, addr, bytes)); |
| 124 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 125 | fList.addToHead(dm); |
| 126 | fUsed += bytes; |
| 127 | this->dumpDownTo(fBudget); |
| 128 | return dm; |
| 129 | } |
| 130 | |
| 131 | void SkDiscardableMemoryPool::free(SkPoolDiscardableMemory* dm) { |
| 132 | // This is called by dm's destructor. |
| 133 | if (dm->fPointer != NULL) { |
| 134 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 135 | sk_free(dm->fPointer); |
| 136 | dm->fPointer = NULL; |
| 137 | SkASSERT(fUsed >= dm->fBytes); |
| 138 | fUsed -= dm->fBytes; |
| 139 | fList.remove(dm); |
| 140 | } else { |
| 141 | SkASSERT(!fList.isInList(dm)); |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | bool SkDiscardableMemoryPool::lock(SkPoolDiscardableMemory* dm) { |
| 146 | SkASSERT(dm != NULL); |
| 147 | if (NULL == dm->fPointer) { |
| 148 | #if LAZY_CACHE_STATS |
| 149 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 150 | ++fCacheMisses; |
| 151 | #endif // LAZY_CACHE_STATS |
| 152 | return false; |
| 153 | } |
| 154 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 155 | if (NULL == dm->fPointer) { |
| 156 | // May have been purged while waiting for lock. |
| 157 | #if LAZY_CACHE_STATS |
| 158 | ++fCacheMisses; |
| 159 | #endif // LAZY_CACHE_STATS |
| 160 | return false; |
| 161 | } |
| 162 | dm->fLocked = true; |
| 163 | fList.remove(dm); |
| 164 | fList.addToHead(dm); |
| 165 | #if LAZY_CACHE_STATS |
| 166 | ++fCacheHits; |
| 167 | #endif // LAZY_CACHE_STATS |
| 168 | return true; |
| 169 | } |
| 170 | |
| 171 | void SkDiscardableMemoryPool::unlock(SkPoolDiscardableMemory* dm) { |
| 172 | SkASSERT(dm != NULL); |
| 173 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 174 | dm->fLocked = false; |
| 175 | this->dumpDownTo(fBudget); |
| 176 | } |
| 177 | |
| 178 | size_t SkDiscardableMemoryPool::getRAMUsed() { |
| 179 | return fUsed; |
| 180 | } |
| 181 | void SkDiscardableMemoryPool::setRAMBudget(size_t budget) { |
| 182 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 183 | fBudget = budget; |
| 184 | this->dumpDownTo(fBudget); |
| 185 | } |
| 186 | void SkDiscardableMemoryPool::dumpPool() { |
| 187 | SkAutoMutexAcquire autoMutexAcquire(fMutex); |
| 188 | this->dumpDownTo(0); |
| 189 | } |
| 190 | |
| 191 | //////////////////////////////////////////////////////////////////////////////// |
| 192 | SK_DECLARE_STATIC_MUTEX(gMutex); |
| 193 | static void create_pool(SkDiscardableMemoryPool** pool) { |
| 194 | SkASSERT(NULL == *pool); |
| 195 | *pool = SkNEW_ARGS(SkDiscardableMemoryPool, |
| 196 | (SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE, |
| 197 | &gMutex)); |
| 198 | } |
| 199 | SkDiscardableMemoryPool* SkGetGlobalDiscardableMemoryPool() { |
| 200 | static SkDiscardableMemoryPool* gPool(NULL); |
| 201 | SK_DECLARE_STATIC_ONCE(create_pool_once); |
| 202 | SkOnce(&create_pool_once, create_pool, &gPool); |
| 203 | SkASSERT(NULL != gPool); |
| 204 | return gPool; |
| 205 | } |
| 206 | |
| 207 | //////////////////////////////////////////////////////////////////////////////// |