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      1 // Copyright 2012 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 CC_RESOURCES_PRIORITIZED_RESOURCE_MANAGER_H_
      6 #define CC_RESOURCES_PRIORITIZED_RESOURCE_MANAGER_H_
      7 
      8 #include <list>
      9 #include <vector>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/containers/hash_tables.h"
     13 #include "base/memory/scoped_ptr.h"
     14 #include "base/synchronization/lock.h"
     15 #include "cc/base/cc_export.h"
     16 #include "cc/resources/prioritized_resource.h"
     17 #include "cc/resources/priority_calculator.h"
     18 #include "cc/resources/resource.h"
     19 #include "cc/trees/proxy.h"
     20 #include "ui/gfx/size.h"
     21 
     22 #if defined(COMPILER_GCC)
     23 namespace BASE_HASH_NAMESPACE {
     24 template <> struct hash<cc::PrioritizedResource*> {
     25   size_t operator()(cc::PrioritizedResource* ptr) const {
     26     return hash<size_t>()(reinterpret_cast<size_t>(ptr));
     27   }
     28 };
     29 }  // namespace BASE_HASH_NAMESPACE
     30 #endif  // COMPILER
     31 
     32 namespace cc {
     33 
     34 class PriorityCalculator;
     35 class Proxy;
     36 
     37 class CC_EXPORT PrioritizedResourceManager {
     38  public:
     39   static scoped_ptr<PrioritizedResourceManager> Create(const Proxy* proxy) {
     40     return make_scoped_ptr(new PrioritizedResourceManager(proxy));
     41   }
     42   scoped_ptr<PrioritizedResource> CreateTexture(
     43       gfx::Size size, ResourceFormat format) {
     44     return make_scoped_ptr(new PrioritizedResource(this, size, format));
     45   }
     46   ~PrioritizedResourceManager();
     47 
     48   typedef std::list<PrioritizedResource::Backing*> BackingList;
     49 
     50   // TODO(epenner): (http://crbug.com/137094) This 64MB default is a straggler
     51   // from the old texture manager and is just to give us a default memory
     52   // allocation before we get a callback from the GPU memory manager. We
     53   // should probaby either:
     54   // - wait for the callback before rendering anything instead
     55   // - push this into the GPU memory manager somehow.
     56   static size_t DefaultMemoryAllocationLimit() { return 64 * 1024 * 1024; }
     57 
     58   // MemoryUseBytes() describes the number of bytes used by existing allocated
     59   // textures.
     60   size_t MemoryUseBytes() const { return memory_use_bytes_; }
     61   // MemoryAboveCutoffBytes() describes the number of bytes that
     62   // would be used if all textures that are above the cutoff were allocated.
     63   // MemoryUseBytes() <= MemoryAboveCutoffBytes() should always be true.
     64   size_t MemoryAboveCutoffBytes() const { return memory_above_cutoff_bytes_; }
     65   // MaxMemoryNeededBytes() describes the number of bytes that would be used
     66   // by textures if there were no limit on memory usage.
     67   size_t MaxMemoryNeededBytes() const { return max_memory_needed_bytes_; }
     68   size_t MemoryForSelfManagedTextures() const {
     69     return max_memory_limit_bytes_ - memory_available_bytes_;
     70   }
     71 
     72   void SetMaxMemoryLimitBytes(size_t bytes) { max_memory_limit_bytes_ = bytes; }
     73   size_t MaxMemoryLimitBytes() const { return max_memory_limit_bytes_; }
     74 
     75   // Sepecify a external priority cutoff. Only textures that have a strictly
     76   // higher priority than this cutoff will be allowed.
     77   void SetExternalPriorityCutoff(int priority_cutoff) {
     78     external_priority_cutoff_ = priority_cutoff;
     79   }
     80   int ExternalPriorityCutoff() const {
     81     return external_priority_cutoff_;
     82   }
     83 
     84   // Return the amount of texture memory required at particular cutoffs.
     85   size_t MemoryVisibleBytes() const;
     86   size_t MemoryVisibleAndNearbyBytes() const;
     87 
     88   void PrioritizeTextures();
     89   void ClearPriorities();
     90 
     91   // Delete contents textures' backing resources until they use only
     92   // limit_bytes bytes. This may be called on the impl thread while the main
     93   // thread is running. Returns true if resources are indeed evicted as a
     94   // result of this call.
     95   bool ReduceMemoryOnImplThread(size_t limit_bytes,
     96                                 int priority_cutoff,
     97                                 ResourceProvider* resource_provider);
     98 
     99   // Returns true if there exist any textures that are linked to backings that
    100   // have had their resources evicted. Only when we commit a tree that has no
    101   // textures linked to evicted backings may we allow drawing. After an
    102   // eviction, this will not become true until unlinkAndClearEvictedBackings
    103   // is called.
    104   bool LinkedEvictedBackingsExist() const;
    105 
    106   // Unlink the list of contents textures' backings from their owning textures
    107   // and delete the evicted backings' structures. This is called just before
    108   // updating layers, and is only ever called on the main thread.
    109   void UnlinkAndClearEvictedBackings();
    110 
    111   bool RequestLate(PrioritizedResource* texture);
    112 
    113   void ReduceWastedMemory(ResourceProvider* resource_provider);
    114   void ReduceMemory(ResourceProvider* resource_provider);
    115   void ClearAllMemory(ResourceProvider* resource_provider);
    116 
    117   void AcquireBackingTextureIfNeeded(PrioritizedResource* texture,
    118                                      ResourceProvider* resource_provider);
    119 
    120   void RegisterTexture(PrioritizedResource* texture);
    121   void UnregisterTexture(PrioritizedResource* texture);
    122   void ReturnBackingTexture(PrioritizedResource* texture);
    123 
    124   // Update all backings' priorities from their owning texture.
    125   void PushTexturePrioritiesToBackings();
    126 
    127   // Mark all textures' backings as being in the drawing impl tree.
    128   void UpdateBackingsState(ResourceProvider* resource_provider);
    129 
    130   const Proxy* ProxyForDebug() const;
    131 
    132  private:
    133   friend class PrioritizedResourceTest;
    134 
    135   enum EvictionPolicy {
    136     EVICT_ONLY_RECYCLABLE,
    137     EVICT_ANYTHING,
    138   };
    139   enum UnlinkPolicy {
    140     DO_NOT_UNLINK_BACKINGS,
    141     UNLINK_BACKINGS,
    142   };
    143 
    144   // Compare textures. Highest priority first.
    145   static inline bool CompareTextures(PrioritizedResource* a,
    146                                      PrioritizedResource* b) {
    147     if (a->request_priority() == b->request_priority())
    148       return a < b;
    149     return PriorityCalculator::priority_is_higher(a->request_priority(),
    150                                                   b->request_priority());
    151   }
    152   // Compare backings. Lowest priority first.
    153   static inline bool CompareBackings(PrioritizedResource::Backing* a,
    154                                      PrioritizedResource::Backing* b) {
    155     // Make textures that can be recycled appear first.
    156     if (a->CanBeRecycledIfNotInExternalUse() !=
    157         b->CanBeRecycledIfNotInExternalUse())
    158       return (a->CanBeRecycledIfNotInExternalUse() >
    159               b->CanBeRecycledIfNotInExternalUse());
    160     // Then sort by being above or below the priority cutoff.
    161     if (a->was_above_priority_cutoff_at_last_priority_update() !=
    162         b->was_above_priority_cutoff_at_last_priority_update())
    163       return (a->was_above_priority_cutoff_at_last_priority_update() <
    164               b->was_above_priority_cutoff_at_last_priority_update());
    165     // Then sort by priority (note that backings that no longer have owners will
    166     // always have the lowest priority).
    167     if (a->request_priority_at_last_priority_update() !=
    168         b->request_priority_at_last_priority_update())
    169       return PriorityCalculator::priority_is_lower(
    170           a->request_priority_at_last_priority_update(),
    171           b->request_priority_at_last_priority_update());
    172     // Then sort by being in the impl tree versus being completely
    173     // unreferenced.
    174     if (a->in_drawing_impl_tree() != b->in_drawing_impl_tree())
    175       return (a->in_drawing_impl_tree() < b->in_drawing_impl_tree());
    176     // Finally, prefer to evict textures in the parent compositor because
    177     // they will otherwise take another roundtrip to the parent compositor
    178     // before they are evicted.
    179     if (a->in_parent_compositor() != b->in_parent_compositor())
    180       return (a->in_parent_compositor() > b->in_parent_compositor());
    181     return a < b;
    182   }
    183 
    184   explicit PrioritizedResourceManager(const Proxy* proxy);
    185 
    186   bool EvictBackingsToReduceMemory(size_t limit_bytes,
    187                                    int priority_cutoff,
    188                                    EvictionPolicy eviction_policy,
    189                                    UnlinkPolicy unlink_policy,
    190                                    ResourceProvider* resource_provider);
    191   PrioritizedResource::Backing* CreateBacking(
    192       gfx::Size size,
    193       ResourceFormat format,
    194       ResourceProvider* resource_provider);
    195   void EvictFirstBackingResource(ResourceProvider* resource_provider);
    196   void SortBackings();
    197 
    198   void AssertInvariants();
    199 
    200   size_t max_memory_limit_bytes_;
    201   // The priority cutoff based on memory pressure. This is not a strict
    202   // cutoff -- RequestLate allows textures with priority equal to this
    203   // cutoff to be allowed.
    204   int priority_cutoff_;
    205   // The priority cutoff based on external memory policy. This is a strict
    206   // cutoff -- no textures with priority equal to this cutoff will be allowed.
    207   int external_priority_cutoff_;
    208   size_t memory_use_bytes_;
    209   size_t memory_above_cutoff_bytes_;
    210   size_t max_memory_needed_bytes_;
    211   size_t memory_available_bytes_;
    212 
    213   typedef base::hash_set<PrioritizedResource*> TextureSet;
    214   typedef std::vector<PrioritizedResource*> TextureVector;
    215 
    216   const Proxy* proxy_;
    217 
    218   TextureSet textures_;
    219   // This list is always sorted in eviction order, with the exception the
    220   // newly-allocated or recycled textures at the very end of the tail that
    221   // are not sorted by priority.
    222   BackingList backings_;
    223   bool backings_tail_not_sorted_;
    224 
    225   // The list of backings that have been evicted, but may still be linked
    226   // to textures. This can be accessed concurrently by the main and impl
    227   // threads, and may only be accessed while holding evicted_backings_lock_.
    228   mutable base::Lock evicted_backings_lock_;
    229   BackingList evicted_backings_;
    230 
    231   TextureVector temp_texture_vector_;
    232 
    233   // Statistics about memory usage at priority cutoffs, computed at
    234   // PrioritizeTextures.
    235   size_t memory_visible_bytes_;
    236   size_t memory_visible_and_nearby_bytes_;
    237 
    238   // Statistics copied at the time of PushTexturePrioritiesToBackings.
    239   size_t memory_visible_last_pushed_bytes_;
    240   size_t memory_visible_and_nearby_last_pushed_bytes_;
    241 
    242   DISALLOW_COPY_AND_ASSIGN(PrioritizedResourceManager);
    243 };
    244 
    245 }  // namespace cc
    246 
    247 #endif  // CC_RESOURCES_PRIORITIZED_RESOURCE_MANAGER_H_
    248