GrResourceCache.cpp revision a79919883e275e7a5e00afc50be10cc721f6ba1d 
1
2/*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11#include "GrResourceCache.h"
12#include "GrResource.h"
13
14
15GrResourceKey::ResourceType GrResourceKey::GenerateResourceType() {
16    static int32_t gNextType = 0;
17
18    int32_t type = sk_atomic_inc(&gNextType);
19    if (type >= (1 << 8 * sizeof(ResourceType))) {
20        GrCrash("Too many Resource Types");
21    }
22
23    return static_cast<ResourceType>(type);
24}
25
26///////////////////////////////////////////////////////////////////////////////
27
28GrResourceEntry::GrResourceEntry(const GrResourceKey& key, GrResource* resource)
29        : fKey(key), fResource(resource) {
30    // we assume ownership of the resource, and will unref it when we die
31    GrAssert(resource);
32    resource->ref();
33}
34
35GrResourceEntry::~GrResourceEntry() {
36    fResource->setCacheEntry(NULL);
37    fResource->unref();
38}
39
40#if GR_DEBUG
41void GrResourceEntry::validate() const {
42    GrAssert(fResource);
43    GrAssert(fResource->getCacheEntry() == this);
44    fResource->validate();
45}
46#endif
47
48///////////////////////////////////////////////////////////////////////////////
49
50GrResourceCache::GrResourceCache(int maxCount, size_t maxBytes) :
51        fMaxCount(maxCount),
52        fMaxBytes(maxBytes) {
53#if GR_CACHE_STATS
54    fHighWaterEntryCount          = 0;
55    fHighWaterEntryBytes          = 0;
56    fHighWaterClientDetachedCount = 0;
57    fHighWaterClientDetachedBytes = 0;
58#endif
59
60    fEntryCount                   = 0;
61    fEntryBytes                   = 0;
62    fClientDetachedCount          = 0;
63    fClientDetachedBytes          = 0;
64
65    fPurging                      = false;
66
67    fOverbudgetCB                 = NULL;
68    fOverbudgetData               = NULL;
69}
70
71GrResourceCache::~GrResourceCache() {
72    GrAutoResourceCacheValidate atcv(this);
73
74    EntryList::Iter iter;
75
76    // Unlike the removeAll, here we really remove everything, including locked resources.
77    while (GrResourceEntry* entry = fList.head()) {
78        GrAutoResourceCacheValidate atcv(this);
79
80        // remove from our cache
81        fCache.remove(entry->fKey, entry);
82
83        // remove from our llist
84        this->internalDetach(entry);
85
86        delete entry;
87    }
88}
89
90void GrResourceCache::getLimits(int* maxResources, size_t* maxResourceBytes) const{
91    if (maxResources) {
92        *maxResources = fMaxCount;
93    }
94    if (maxResourceBytes) {
95        *maxResourceBytes = fMaxBytes;
96    }
97}
98
99void GrResourceCache::setLimits(int maxResources, size_t maxResourceBytes) {
100    bool smaller = (maxResources < fMaxCount) || (maxResourceBytes < fMaxBytes);
101
102    fMaxCount = maxResources;
103    fMaxBytes = maxResourceBytes;
104
105    if (smaller) {
106        this->purgeAsNeeded();
107    }
108}
109
110void GrResourceCache::internalDetach(GrResourceEntry* entry,
111                                     BudgetBehaviors behavior) {
112    fList.remove(entry);
113
114    // update our stats
115    if (kIgnore_BudgetBehavior == behavior) {
116        fClientDetachedCount += 1;
117        fClientDetachedBytes += entry->resource()->sizeInBytes();
118
119#if GR_CACHE_STATS
120        if (fHighWaterClientDetachedCount < fClientDetachedCount) {
121            fHighWaterClientDetachedCount = fClientDetachedCount;
122        }
123        if (fHighWaterClientDetachedBytes < fClientDetachedBytes) {
124            fHighWaterClientDetachedBytes = fClientDetachedBytes;
125        }
126#endif
127
128    } else {
129        GrAssert(kAccountFor_BudgetBehavior == behavior);
130
131        fEntryCount -= 1;
132        fEntryBytes -= entry->resource()->sizeInBytes();
133    }
134}
135
136void GrResourceCache::attachToHead(GrResourceEntry* entry,
137                                   BudgetBehaviors behavior) {
138    fList.addToHead(entry);
139
140    // update our stats
141    if (kIgnore_BudgetBehavior == behavior) {
142        fClientDetachedCount -= 1;
143        fClientDetachedBytes -= entry->resource()->sizeInBytes();
144    } else {
145        GrAssert(kAccountFor_BudgetBehavior == behavior);
146
147        fEntryCount += 1;
148        fEntryBytes += entry->resource()->sizeInBytes();
149
150#if GR_CACHE_STATS
151        if (fHighWaterEntryCount < fEntryCount) {
152            fHighWaterEntryCount = fEntryCount;
153        }
154        if (fHighWaterEntryBytes < fEntryBytes) {
155            fHighWaterEntryBytes = fEntryBytes;
156        }
157#endif
158    }
159}
160
161// This functor just searches for an entry with only a single ref (from
162// the texture cache itself). Presumably in this situation no one else
163// is relying on the texture.
164class GrTFindUnreffedFunctor {
165public:
166    bool operator()(const GrResourceEntry* entry) const {
167        return 1 == entry->resource()->getRefCnt();
168    }
169};
170
171GrResource* GrResourceCache::find(const GrResourceKey& key, uint32_t ownershipFlags) {
172    GrAutoResourceCacheValidate atcv(this);
173
174    GrResourceEntry* entry = NULL;
175
176    if (ownershipFlags & kNoOtherOwners_OwnershipFlag) {
177        GrTFindUnreffedFunctor functor;
178
179        entry = fCache.find<GrTFindUnreffedFunctor>(key, functor);
180    } else {
181        entry = fCache.find(key);
182    }
183
184    if (NULL == entry) {
185        return NULL;
186    }
187
188    if (ownershipFlags & kHide_OwnershipFlag) {
189        this->makeExclusive(entry);
190    } else {
191        // Make this resource MRU
192        this->internalDetach(entry);
193        this->attachToHead(entry);
194    }
195
196    return entry->fResource;
197}
198
199bool GrResourceCache::hasKey(const GrResourceKey& key) const {
200    return NULL != fCache.find(key);
201}
202
203void GrResourceCache::addResource(const GrResourceKey& key,
204                                  GrResource* resource,
205                                  uint32_t ownershipFlags) {
206    GrAssert(NULL == resource->getCacheEntry());
207    // we don't expect to create new resources during a purge. In theory
208    // this could cause purgeAsNeeded() into an infinite loop (e.g.
209    // each resource destroyed creates and locks 2 resources and
210    // unlocks 1 thereby causing a new purge).
211    GrAssert(!fPurging);
212    GrAutoResourceCacheValidate atcv(this);
213
214    GrResourceEntry* entry = SkNEW_ARGS(GrResourceEntry, (key, resource));
215    resource->setCacheEntry(entry);
216
217    this->attachToHead(entry);
218    fCache.insert(key, entry);
219
220    if (ownershipFlags & kHide_OwnershipFlag) {
221        this->makeExclusive(entry);
222    }
223
224}
225
226void GrResourceCache::makeExclusive(GrResourceEntry* entry) {
227    GrAutoResourceCacheValidate atcv(this);
228
229    // When scratch textures are detached (to hide them from future finds) they
230    // still count against the resource budget
231    this->internalDetach(entry, kIgnore_BudgetBehavior);
232    fCache.remove(entry->key(), entry);
233
234#if GR_DEBUG
235    fExclusiveList.addToHead(entry);
236#endif
237}
238
239void GrResourceCache::removeInvalidResource(GrResourceEntry* entry) {
240    // If the resource went invalid while it was detached then purge it
241    // This can happen when a 3D context was lost,
242    // the client called GrContext::contextDestroyed() to notify Gr,
243    // and then later an SkGpuDevice's destructor releases its backing
244    // texture (which was invalidated at contextDestroyed time).
245    fClientDetachedCount -= 1;
246    fEntryCount -= 1;
247    size_t size = entry->resource()->sizeInBytes();
248    fClientDetachedBytes -= size;
249    fEntryBytes -= size;
250}
251
252void GrResourceCache::makeNonExclusive(GrResourceEntry* entry) {
253    GrAutoResourceCacheValidate atcv(this);
254
255#if GR_DEBUG
256    fExclusiveList.remove(entry);
257#endif
258
259    if (entry->resource()->isValid()) {
260        // Since scratch textures still count against the cache budget even
261        // when they have been removed from the cache, re-adding them doesn't
262        // alter the budget information.
263        attachToHead(entry, kIgnore_BudgetBehavior);
264        fCache.insert(entry->key(), entry);
265    } else {
266        this->removeInvalidResource(entry);
267    }
268}
269
270/**
271 * Destroying a resource may potentially trigger the unlock of additional
272 * resources which in turn will trigger a nested purge. We block the nested
273 * purge using the fPurging variable. However, the initial purge will keep
274 * looping until either all resources in the cache are unlocked or we've met
275 * the budget. There is an assertion in createAndLock to check against a
276 * resource's destructor inserting new resources into the cache. If these
277 * new resources were unlocked before purgeAsNeeded completed it could
278 * potentially make purgeAsNeeded loop infinitely.
279 *
280 * extraCount and extraBytes are added to the current resource totals to account
281 * for incoming resources (e.g., GrContext is about to add 10MB split between
282 * 10 textures).
283 */
284void GrResourceCache::purgeAsNeeded(int extraCount, size_t extraBytes) {
285    if (fPurging) {
286        return;
287    }
288
289    fPurging = true;
290
291    this->internalPurge(extraCount, extraBytes);
292    if (((fEntryCount+extraCount) > fMaxCount ||
293        (fEntryBytes+extraBytes) > fMaxBytes) &&
294        NULL != fOverbudgetCB) {
295        // Despite the purge we're still over budget. See if Ganesh can
296        // release some resources and purge again.
297        if ((*fOverbudgetCB)(fOverbudgetData)) {
298            this->internalPurge(extraCount, extraBytes);
299        }
300    }
301
302    fPurging = false;
303}
304
305void GrResourceCache::internalPurge(int extraCount, size_t extraBytes) {
306    SkASSERT(fPurging);
307
308    bool withinBudget = false;
309    bool changed = false;
310
311    // The purging process is repeated several times since one pass
312    // may free up other resources
313    do {
314        EntryList::Iter iter;
315
316        changed = false;
317
318        // Note: the following code relies on the fact that the
319        // doubly linked list doesn't invalidate its data/pointers
320        // outside of the specific area where a deletion occurs (e.g.,
321        // in internalDetach)
322        GrResourceEntry* entry = iter.init(fList, EntryList::Iter::kTail_IterStart);
323
324        while (NULL != entry) {
325            GrAutoResourceCacheValidate atcv(this);
326
327            if ((fEntryCount+extraCount) <= fMaxCount &&
328                (fEntryBytes+extraBytes) <= fMaxBytes) {
329                withinBudget = true;
330                break;
331            }
332
333            GrResourceEntry* prev = iter.prev();
334            if (1 == entry->fResource->getRefCnt()) {
335                changed = true;
336
337                // remove from our cache
338                fCache.remove(entry->key(), entry);
339
340                // remove from our llist
341                this->internalDetach(entry);
342                delete entry;
343            }
344            entry = prev;
345        }
346    } while (!withinBudget && changed);
347}
348
349void GrResourceCache::purgeAllUnlocked() {
350    GrAutoResourceCacheValidate atcv(this);
351
352    // we can have one GrResource holding a lock on another
353    // so we don't want to just do a simple loop kicking each
354    // entry out. Instead change the budget and purge.
355
356    int savedMaxBytes = fMaxBytes;
357    int savedMaxCount = fMaxCount;
358    fMaxBytes = (size_t) -1;
359    fMaxCount = 0;
360    this->purgeAsNeeded();
361
362#if GR_DEBUG
363    GrAssert(fExclusiveList.countEntries() == fClientDetachedCount);
364    GrAssert(countBytes(fExclusiveList) == fClientDetachedBytes);
365    if (!fCache.count()) {
366        // Items may have been detached from the cache (such as the backing
367        // texture for an SkGpuDevice). The above purge would not have removed
368        // them.
369        GrAssert(fEntryCount == fClientDetachedCount);
370        GrAssert(fEntryBytes == fClientDetachedBytes);
371        GrAssert(fList.isEmpty());
372    }
373#endif
374
375    fMaxBytes = savedMaxBytes;
376    fMaxCount = savedMaxCount;
377}
378
379///////////////////////////////////////////////////////////////////////////////
380
381#if GR_DEBUG
382size_t GrResourceCache::countBytes(const EntryList& list) {
383    size_t bytes = 0;
384
385    EntryList::Iter iter;
386
387    const GrResourceEntry* entry = iter.init(const_cast<EntryList&>(list),
388                                             EntryList::Iter::kTail_IterStart);
389
390    for ( ; NULL != entry; entry = iter.prev()) {
391        bytes += entry->resource()->sizeInBytes();
392    }
393    return bytes;
394}
395
396static bool both_zero_or_nonzero(int count, size_t bytes) {
397    return (count == 0 && bytes == 0) || (count > 0 && bytes > 0);
398}
399
400void GrResourceCache::validate() const {
401    fList.validate();
402    fExclusiveList.validate();
403    GrAssert(both_zero_or_nonzero(fEntryCount, fEntryBytes));
404    GrAssert(both_zero_or_nonzero(fClientDetachedCount, fClientDetachedBytes));
405    GrAssert(fClientDetachedBytes <= fEntryBytes);
406    GrAssert(fClientDetachedCount <= fEntryCount);
407    GrAssert((fEntryCount - fClientDetachedCount) == fCache.count());
408
409    fCache.validate();
410
411
412    EntryList::Iter iter;
413
414    // check that the exclusively held entries are okay
415    const GrResourceEntry* entry = iter.init(const_cast<EntryList&>(fExclusiveList),
416                                             EntryList::Iter::kHead_IterStart);
417
418    for ( ; NULL != entry; entry = iter.next()) {
419        entry->validate();
420    }
421
422    // check that the shareable entries are okay
423    entry = iter.init(const_cast<EntryList&>(fList), EntryList::Iter::kHead_IterStart);
424
425    int count = 0;
426    for ( ; NULL != entry; entry = iter.next()) {
427        entry->validate();
428        GrAssert(fCache.find(entry->key()));
429        count += 1;
430    }
431    GrAssert(count == fEntryCount - fClientDetachedCount);
432
433    size_t bytes = countBytes(fList);
434    GrAssert(bytes == fEntryBytes  - fClientDetachedBytes);
435
436    bytes = countBytes(fExclusiveList);
437    GrAssert(bytes == fClientDetachedBytes);
438
439    GrAssert(fList.countEntries() == fEntryCount - fClientDetachedCount);
440
441    GrAssert(fExclusiveList.countEntries() == fClientDetachedCount);
442}
443#endif // GR_DEBUG
444
445#if GR_CACHE_STATS
446
447void GrResourceCache::printStats() {
448    int locked = 0;
449
450    EntryList::Iter iter;
451
452    GrResourceEntry* entry = iter.init(fList, EntryList::Iter::kTail_IterStart);
453
454    for ( ; NULL != entry; entry = iter.prev()) {
455        if (entry->fResource->getRefCnt() > 1) {
456            ++locked;
457        }
458    }
459
460    SkDebugf("Budget: %d items %d bytes\n", fMaxCount, fMaxBytes);
461    SkDebugf("\t\tEntry Count: current %d (%d locked) high %d\n",
462                fEntryCount, locked, fHighWaterEntryCount);
463    SkDebugf("\t\tEntry Bytes: current %d high %d\n",
464                fEntryBytes, fHighWaterEntryBytes);
465    SkDebugf("\t\tDetached Entry Count: current %d high %d\n",
466                fClientDetachedCount, fHighWaterClientDetachedCount);
467    SkDebugf("\t\tDetached Bytes: current %d high %d\n",
468                fClientDetachedBytes, fHighWaterClientDetachedBytes);
469}
470
471#endif
472
473///////////////////////////////////////////////////////////////////////////////
474