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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_TILES_GPU_IMAGE_DECODE_CACHE_H_
#define CC_TILES_GPU_IMAGE_DECODE_CACHE_H_
#include <memory>
#include <unordered_map>
#include <vector>
#include "base/containers/mru_cache.h"
#include "base/memory/discardable_memory.h"
#include "base/memory/memory_coordinator_client.h"
#include "base/synchronization/lock.h"
#include "base/trace_event/memory_dump_provider.h"
#include "cc/cc_export.h"
#include "cc/tiles/image_decode_cache.h"
#include "third_party/skia/include/core/SkRefCnt.h"
#include "third_party/skia/include/gpu/gl/GrGLTypes.h"
namespace viz {
class RasterContextProvider;
}
namespace cc {
// OVERVIEW:
//
// GpuImageDecodeCache handles the decode and upload of images that will
// be used by Skia's GPU raster path. It also maintains a cache of these
// decoded/uploaded images for later re-use.
//
// Generally, when an image is required for raster, GpuImageDecodeCache
// creates two tasks, one to decode the image, and one to upload the image to
// the GPU. These tasks are completed before the raster task which depends on
// the image. We need to seperate decode and upload tasks, as decode can occur
// simultaneously on multiple threads, while upload requires the GL context
// lock must happen on our non-concurrent raster thread.
//
// Decoded and Uploaded image data share a single cache entry. Depending on how
// far we've progressed, this cache entry may contain CPU-side decoded data,
// GPU-side uploaded data, or both. CPU-side decoded data is stored in software
// discardable memory and is only locked for short periods of time (until the
// upload completes). Uploaded GPU data is stored in GPU discardable memory and
// remains locked for the duration of the raster tasks which depend on it.
//
// In cases where the size of locked GPU images exceeds our working set limits,
// we operate in an "at-raster" mode. In this mode, there are no decode/upload
// tasks, and images are decoded/uploaded as needed, immediately before being
// used in raster. Cache entries for at-raster tasks are marked as such, which
// prevents future tasks from taking a dependency on them and extending their
// lifetime longer than is necessary.
//
// RASTER-SCALE CACHING:
//
// In order to save memory, images which are going to be scaled may be uploaded
// at lower than original resolution. In these cases, we may later need to
// re-upload the image at a higher resolution. To handle multiple images of
// different scales being in use at the same time, we have a two-part caching
// system.
//
// The first cache, |persistent_cache_|, stores one ImageData per image id.
// These ImageDatas are not necessarily associated with a given DrawImage, and
// are saved (persisted) even when their ref-count reaches zero (assuming they
// fit in the current memory budget). This allows for future re-use of image
// resources.
//
// The second cache, |in_use_cache_|, stores one image data per DrawImage -
// this may be the same ImageData that is in the persistent_cache_. These
// cache entries are more transient and are deleted as soon as all refs to the
// given DrawImage are released (the image is no longer in-use).
//
// For examples of raster-scale caching, see https://goo.gl/0zCd9Z
//
// REF COUNTING:
//
// In dealing with the two caches in GpuImageDecodeCache, there are three
// ref-counting concepts in use:
// 1) ImageData upload/decode ref-counts.
// These ref-counts represent the overall number of references to the
// upload or decode portion of an ImageData. These ref-counts control
// both whether the upload/decode data can be freed, as well as whether an
// ImageData can be removed from the |persistent_cache_|. ImageDatas are
// only removed from the |persistent_cache_| if their upload/decode
// ref-counts are zero or if they are orphaned and replaced by a new entry.
// 2) InUseCacheEntry ref-counts.
// These ref-counts represent the number of references to an
// InUseCacheEntry from a specific DrawImage. When the InUseCacheEntry's
// ref-count reaches 0 it will be deleted.
// 3) scoped_refptr ref-counts.
// Because both the persistent_cache_ and the in_use_cache_ point at the
// same ImageDatas (and may need to keep these ImageDatas alive independent
// of each other), they hold ImageDatas by scoped_refptr. The scoped_refptr
// keeps an ImageData alive while it is present in either the
// |persistent_cache_| or |in_use_cache_|.
//
class CC_EXPORT GpuImageDecodeCache
: public ImageDecodeCache,
public base::trace_event::MemoryDumpProvider,
public base::MemoryCoordinatorClient {
public:
enum class DecodeTaskType { kPartOfUploadTask, kStandAloneDecodeTask };
explicit GpuImageDecodeCache(viz::RasterContextProvider* context,
bool use_transfer_cache,
SkColorType color_type,
size_t max_working_set_bytes);
~GpuImageDecodeCache() override;
// ImageDecodeCache overrides.
// Finds the existing uploaded image for the provided DrawImage. Creates an
// upload task to upload the image if an exsiting image does not exist.
TaskResult GetTaskForImageAndRef(const DrawImage& image,
const TracingInfo& tracing_info) override;
TaskResult GetOutOfRasterDecodeTaskForImageAndRef(
const DrawImage& image) override;
void UnrefImage(const DrawImage& image) override;
DecodedDrawImage GetDecodedImageForDraw(const DrawImage& draw_image) override;
void DrawWithImageFinished(const DrawImage& image,
const DecodedDrawImage& decoded_image) override;
void ReduceCacheUsage() override;
void SetShouldAggressivelyFreeResources(
bool aggressively_free_resources) override;
void ClearCache() override;
size_t GetMaximumMemoryLimitBytes() const override;
void NotifyImageUnused(const PaintImage::FrameKey& frame_key) override;
// MemoryDumpProvider overrides.
bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
base::trace_event::ProcessMemoryDump* pmd) override;
// base::MemoryCoordinatorClient overrides.
void OnMemoryStateChange(base::MemoryState state) override;
void OnPurgeMemory() override;
// Called by Decode / Upload tasks.
void DecodeImage(const DrawImage& image, TaskType task_type);
void UploadImage(const DrawImage& image);
// Called by Decode / Upload tasks when tasks are finished.
void OnImageDecodeTaskCompleted(const DrawImage& image,
DecodeTaskType task_type);
void OnImageUploadTaskCompleted(const DrawImage& image);
// For testing only.
void SetWorkingSetLimitForTesting(size_t limit) {
max_working_set_bytes_ = limit;
}
size_t GetWorkingSetBytesForTesting() const { return working_set_bytes_; }
size_t GetNumCacheEntriesForTesting() const {
return persistent_cache_.size();
}
size_t GetInUseCacheEntriesForTesting() const { return in_use_cache_.size(); }
size_t GetDrawImageSizeForTesting(const DrawImage& image);
void SetImageDecodingFailedForTesting(const DrawImage& image);
bool DiscardableIsLockedForTesting(const DrawImage& image);
bool IsInInUseCacheForTesting(const DrawImage& image) const;
private:
enum class DecodedDataMode { kGpu, kCpu, kTransferCache };
// Stores stats tracked by both DecodedImageData and UploadedImageData.
struct ImageDataBase {
ImageDataBase();
~ImageDataBase();
bool is_locked() const { return is_locked_; }
void OnSetLockedData(bool out_of_raster);
void OnResetData();
void OnLock();
void OnUnlock();
void mark_used() {
DCHECK(is_locked_);
usage_stats_.used = true;
}
uint32_t ref_count = 0;
// If non-null, this is the pending task to populate this data.
scoped_refptr<TileTask> task;
protected:
struct UsageStats {
int lock_count = 1;
bool used = false;
bool first_lock_out_of_raster = false;
bool first_lock_wasted = false;
};
// Returns the usage state (see cc file) for histogram logging.
int UsageState() const;
bool is_locked_ = false;
UsageStats usage_stats_;
};
// Stores the CPU-side decoded bits of an image and supporting fields.
struct DecodedImageData : public ImageDataBase {
DecodedImageData();
~DecodedImageData();
bool Lock();
void Unlock();
void SetLockedData(std::unique_ptr<base::DiscardableMemory> data,
sk_sp<SkImage> image,
bool out_of_raster);
void ResetData();
base::DiscardableMemory* data() const { return data_.get(); }
sk_sp<SkImage> image() const {
DCHECK(is_locked());
return image_;
}
bool decode_failure = false;
// Similar to |task|, but only is generated if there is no associated upload
// generated for this task (ie, this is an out-of-raster request for decode.
scoped_refptr<TileTask> stand_alone_task;
private:
void ReportUsageStats() const;
std::unique_ptr<base::DiscardableMemory> data_;
sk_sp<SkImage> image_;
};
// Stores the GPU-side image and supporting fields.
struct UploadedImageData : public ImageDataBase {
UploadedImageData();
~UploadedImageData();
void SetImage(sk_sp<SkImage> image);
void SetTransferCacheId(uint32_t id);
void Reset();
// If in image mode.
const sk_sp<SkImage>& image() const {
DCHECK(mode_ == Mode::kSkImage || mode_ == Mode::kNone);
return image_;
}
GrGLuint gl_id() const {
DCHECK(mode_ == Mode::kSkImage || mode_ == Mode::kNone);
return gl_id_;
}
// If in transfer cache mode.
base::Optional<uint32_t> transfer_cache_id() const {
DCHECK(mode_ == Mode::kTransferCache || mode_ == Mode::kNone);
return transfer_cache_id_;
}
// True if the image is counting against our working set limits.
bool budgeted = false;
private:
// Used for internal DCHECKs only.
enum class Mode {
kNone,
kSkImage,
kTransferCache,
};
void ReportUsageStats() const;
Mode mode_ = Mode::kNone;
// Used if |mode_| == kSkImage.
// May be null if image not yet uploaded / prepared.
sk_sp<SkImage> image_;
GrGLuint gl_id_ = 0;
// Used if |mode_| == kTransferCache.
base::Optional<uint32_t> transfer_cache_id_;
};
struct ImageData : public base::RefCountedThreadSafe<ImageData> {
ImageData(DecodedDataMode mode,
size_t size,
const gfx::ColorSpace& target_color_space,
SkFilterQuality quality,
int mip_level);
bool IsGpuOrTransferCache() const;
bool HasUploadedData() const;
const DecodedDataMode mode;
const size_t size;
gfx::ColorSpace target_color_space;
SkFilterQuality quality;
int mip_level;
bool is_at_raster = false;
// If true, this image is no longer in our |persistent_cache_| and will be
// deleted as soon as its ref count reaches zero.
bool is_orphaned = false;
DecodedImageData decode;
UploadedImageData upload;
private:
friend class base::RefCountedThreadSafe<ImageData>;
~ImageData();
};
// A ref-count and ImageData, used to associate the ImageData with a specific
// DrawImage in the |in_use_cache_|.
struct InUseCacheEntry {
explicit InUseCacheEntry(scoped_refptr<ImageData> image_data);
InUseCacheEntry(const InUseCacheEntry& other);
InUseCacheEntry(InUseCacheEntry&& other);
~InUseCacheEntry();
uint32_t ref_count = 0;
scoped_refptr<ImageData> image_data;
};
// Uniquely identifies (without collisions) a specific DrawImage for use in
// the |in_use_cache_|.
struct InUseCacheKeyHash;
struct InUseCacheKey {
static InUseCacheKey FromDrawImage(const DrawImage& draw_image);
bool operator==(const InUseCacheKey& other) const;
private:
friend struct GpuImageDecodeCache::InUseCacheKeyHash;
explicit InUseCacheKey(const DrawImage& draw_image);
PaintImage::FrameKey frame_key;
int mip_level;
SkFilterQuality filter_quality;
gfx::ColorSpace target_color_space;
};
struct InUseCacheKeyHash {
size_t operator()(const InUseCacheKey&) const;
};
// All private functions should only be called while holding |lock_|. Some
// functions also require the |context_| lock. These are indicated by
// additional comments.
// Similar to GetTaskForImageAndRef, but gets the dependent decode task
// rather than the upload task, if necessary.
scoped_refptr<TileTask> GetImageDecodeTaskAndRef(
const DrawImage& image,
const TracingInfo& tracing_info,
DecodeTaskType task_type);
// Note that this function behaves as if it was public (all of the same locks
// need to be acquired).
TaskResult GetTaskForImageAndRefInternal(const DrawImage& image,
const TracingInfo& tracing_info,
DecodeTaskType task_type);
void RefImageDecode(const DrawImage& draw_image);
void UnrefImageDecode(const DrawImage& draw_image);
void RefImage(const DrawImage& draw_image);
void UnrefImageInternal(const DrawImage& draw_image);
// Called any time the ownership of an object changed. This includes changes
// to ref-count or to orphaned status.
void OwnershipChanged(const DrawImage& draw_image, ImageData* image_data);
// Ensures that the working set can hold an element of |required_size|,
// freeing unreferenced cache entries to make room.
bool EnsureCapacity(size_t required_size);
bool CanFitInWorkingSet(size_t size) const;
bool ExceedsPreferredCount() const;
void DecodeImageIfNecessary(const DrawImage& draw_image,
ImageData* image_data,
TaskType task_type);
scoped_refptr<GpuImageDecodeCache::ImageData> CreateImageData(
const DrawImage& image);
SkImageInfo CreateImageInfoForDrawImage(const DrawImage& draw_image,
int upload_scale_mip_level) const;
// Finds the ImageData that should be used for the given DrawImage. Looks
// first in the |in_use_cache_|, and then in the |persistent_cache_|.
ImageData* GetImageDataForDrawImage(const DrawImage& image);
// Returns true if the given ImageData can be used to draw the specified
// DrawImage.
bool IsCompatible(const ImageData* image_data,
const DrawImage& draw_image) const;
// Helper to delete an image and remove it from the cache. Ensures that
// the image is unlocked and Skia cleanup is handled on the right thread.
void DeleteImage(ImageData* image_data);
// Helper to unlock an image, indicating that it is no longer actively
// being used. An image must be locked via TryLockImage below before it
// can be used again.
void UnlockImage(ImageData* image_data);
// Attempts to lock an image for use. If locking fails (the image is deleted
// on the service side), this function will delete the local reference to the
// image and return false.
enum class HaveContextLock { kYes, kNo };
bool TryLockImage(HaveContextLock have_context_lock,
const DrawImage& draw_image,
ImageData* data);
// Requires that the |context_| lock be held when calling.
void UploadImageIfNecessary(const DrawImage& draw_image,
ImageData* image_data);
// Runs pending operations that required the |context_| lock to be held, but
// were queued up during a time when the |context_| lock was unavailable.
// These including deleting, unlocking, and locking textures.
void RunPendingContextThreadOperations();
bool SupportsColorSpaces() const;
void CheckContextLockAcquiredIfNecessary();
const SkColorType color_type_;
const bool use_transfer_cache_ = false;
viz::RasterContextProvider* context_;
int max_texture_size_ = 0;
// All members below this point must only be accessed while holding |lock_|.
// The exception are const members like |normal_max_cache_bytes_| that can
// be accessed without a lock since they are thread safe.
base::Lock lock_;
// |persistent_cache_| represents the long-lived cache, keeping a certain
// budget of ImageDatas alive even when their ref count reaches zero.
using PersistentCache = base::HashingMRUCache<PaintImage::FrameKey,
scoped_refptr<ImageData>,
PaintImage::FrameKeyHash>;
PersistentCache persistent_cache_;
// |in_use_cache_| represents the in-use (short-lived) cache. Entries are
// cleaned up as soon as their ref count reaches zero.
using InUseCache =
std::unordered_map<InUseCacheKey, InUseCacheEntry, InUseCacheKeyHash>;
InUseCache in_use_cache_;
size_t max_working_set_bytes_ = 0;
size_t working_set_bytes_ = 0;
base::MemoryState memory_state_ = base::MemoryState::NORMAL;
bool aggressively_freeing_resources_ = false;
// We can't modify GPU backed SkImages without holding the context lock, so
// we queue up operations to run the next time the lock is held.
std::vector<SkImage*> images_pending_complete_lock_;
std::vector<SkImage*> images_pending_unlock_;
std::vector<sk_sp<SkImage>> images_pending_deletion_;
std::vector<uint32_t> ids_pending_unlock_;
std::vector<uint32_t> ids_pending_deletion_;
// Records the maximum number of items in the cache over the lifetime of the
// cache. This is updated anytime we are requested to reduce cache usage.
size_t lifetime_max_items_in_cache_ = 0u;
};
} // namespace cc
#endif // CC_TILES_GPU_IMAGE_DECODE_CACHE_H_