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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef mozilla_layers_SurfacePoolCA_h
#define mozilla_layers_SurfacePoolCA_h
#include <IOSurface/IOSurface.h>
#include <deque>
#include <unordered_map>
#include "mozilla/Atomics.h"
#include "mozilla/DataMutex.h"
#include "mozilla/layers/SurfacePool.h"
#include "CFTypeRefPtr.h"
#include "nsISupportsImpl.h"
namespace mozilla {
namespace gl {
class MozFramebuffer;
} // namespace gl
namespace layers {
class SurfacePoolHandleCA;
struct SurfacePoolCAWrapperForGL;
// An implementation of SurfacePool for IOSurfaces and GL framebuffers.
// The goal of having this pool is to avoid creating and destroying IOSurfaces
// and framebuffers frequently, because doing so is expensive.
// SurfacePoolCA is threadsafe. All its data is wrapped inside LockedPool, and
// each access to LockedPool is guarded with a lock through DataMutex.
// The pool satisfies the following requirements:
// - It can be shared across windows, even across windows with different
// GLContexts.
// - The number of unused surfaces that are available for recycling is capped
// to a fixed value per pool, regardless of how many windows use that pool.
// - When all windows are closed (all handles are gone), no surfaces are kept
// alive (the pool is destroyed).
// - There is an explicit way of deleting GL resources for a GLContext so that
// it can happen at a deterministic time on the right thread.
// - Additionally, once a GLContext is no longer being used in any window
// (really: any pool handle), all surface-associated GL resources of that
// context are destroyed.
// - For every IOSurface, only one set of GL resources is in existence at any
// given time. We don't want there to be framebuffers in two different
// GLContexts for one surface.
// - We do not want to recycle an IOSurface that currently has GL resources of
// context A for a pool handle that uses context B.
// - We need to delay IOSurface recycling until the window server is done with
// the surface (`!IOSurfaceIsInUse(surf)`)
class SurfacePoolCA final : public SurfacePool {
// Get a handle for a new window. aGL can be nullptr.
RefPtr<SurfacePoolHandle> GetHandleForGL(gl::GLContext* aGL) override;
// Destroy all GL resources associated with aGL managed by this pool.
void DestroyGLResourcesForContext(gl::GLContext* aGL) override;
friend struct SurfacePoolCAWrapperForGL;
friend class SurfacePoolHandleCA;
friend RefPtr<SurfacePool> SurfacePool::Create(size_t aPoolSizeLimit);
explicit SurfacePoolCA(size_t aPoolSizeLimit);
~SurfacePoolCA() override;
// Get an existing surface of aSize from the pool or create a new surface.
// The returned surface is guaranteed not to be in use by the window server.
CFTypeRefPtr<IOSurfaceRef> ObtainSurfaceFromPool(const gfx::IntSize& aSize,
gl::GLContext* aGL);
// Place a surface that was previously obtained from this pool back into the
// pool. aSurface may or may not be in use by the window server.
void ReturnSurfaceToPool(CFTypeRefPtr<IOSurfaceRef> aSurface);
// Re-run checks whether the window server still uses IOSurfaces which are
// eligible for recycling. The purpose of the "generation" counter is to
// reduce the number of calls to IOSurfaceIsInUse in a scenario where many
// windows / handles are calling CollectPendingSurfaces in the same frame
// (i.e. multiple simultaneously-animating windows).
uint64_t CollectPendingSurfaces(uint64_t aCheckGenerationsUpTo);
// Enforce the pool size limit by evicting surfaces as necessary. This should
// happen at the end of the frame so that we can temporarily exceed the limit
// within a frame.
void EnforcePoolSizeLimit();
// Get or create the framebuffer for the given surface and GL context.
// The returned framebuffer handle will become invalid once
// DestroyGLResourcesForContext or DecrementGLContextHandleCount are called.
// The framebuffer's depth buffer (if present) may be shared between multiple
// framebuffers! Do not assume anything about the depth buffer's existing
// contents (i.e. clear it at the beginning of the draw), and do not
// interleave drawing commands to different framebuffers in such a way that
// the shared depth buffer could cause trouble.
Maybe<GLuint> GetFramebufferForSurface(CFTypeRefPtr<IOSurfaceRef> aSurface,
gl::GLContext* aGL,
bool aNeedsDepthBuffer);
// Called by the destructor of SurfacePoolCAWrapperForGL so that we can clear
// our weak reference to it and delete GL resources.
void OnWrapperDestroyed(gl::GLContext* aGL,
SurfacePoolCAWrapperForGL* aWrapper);
// The actual pool implementation lives in LockedPool, which is accessed in
// a thread-safe manner.
struct LockedPool {
explicit LockedPool(size_t aPoolSizeLimit);
LockedPool(LockedPool&&) = default;
RefPtr<SurfacePoolCAWrapperForGL> GetWrapperForGL(SurfacePoolCA* aPool,
gl::GLContext* aGL);
void DestroyGLResourcesForContext(gl::GLContext* aGL);
CFTypeRefPtr<IOSurfaceRef> ObtainSurfaceFromPool(const gfx::IntSize& aSize,
gl::GLContext* aGL);
void ReturnSurfaceToPool(CFTypeRefPtr<IOSurfaceRef> aSurface);
uint64_t CollectPendingSurfaces(uint64_t aCheckGenerationsUpTo);
void EnforcePoolSizeLimit();
Maybe<GLuint> GetFramebufferForSurface(CFTypeRefPtr<IOSurfaceRef> aSurface,
gl::GLContext* aGL,
bool aNeedsDepthBuffer);
void OnWrapperDestroyed(gl::GLContext* aGL,
SurfacePoolCAWrapperForGL* aWrapper);
uint64_t EstimateTotalMemory();
uint64_t mCollectionGeneration = 0;
struct GLResourcesForSurface {
RefPtr<gl::GLContext> mGLContext; // non-null
UniquePtr<gl::MozFramebuffer> mFramebuffer; // non-null
struct SurfacePoolEntry {
gfx::IntSize mSize;
CFTypeRefPtr<IOSurfaceRef> mIOSurface; // non-null
Maybe<GLResourcesForSurface> mGLResources;
struct PendingSurfaceEntry {
SurfacePoolEntry mEntry;
// The value of LockedPool::mCollectionGeneration at the time
// IOSurfaceIsInUse was last called for mEntry.mIOSurface.
uint64_t mPreviousCheckGeneration;
// The number of times an IOSurfaceIsInUse check has been performed.
uint64_t mCheckCount;
template <typename F>
void MutateEntryStorage(const char* aMutationType,
const gfx::IntSize& aSize, F aFn);
template <typename F>
void ForEachEntry(F aFn);
bool CanRecycleSurfaceForRequest(const SurfacePoolEntry& aEntry,
const gfx::IntSize& aSize,
gl::GLContext* aGL);
RefPtr<gl::DepthAndStencilBuffer> GetDepthBufferForSharing(
gl::GLContext* aGL, const gfx::IntSize& aSize);
UniquePtr<gl::MozFramebuffer> CreateFramebufferForTexture(
gl::GLContext* aGL, const gfx::IntSize& aSize, GLuint aTexture,
bool aNeedsDepthBuffer);
// Every IOSurface that is managed by the pool is wrapped in a
// SurfacePoolEntry object. Every entry is stored in one of three buckets at
// any given time: mInUseEntries, mPendingEntries, or mAvailableEntries. All
// mutations to these buckets are performed via calls to
// MutateEntryStorage(). Entries can move between the buckets in the
// following ways:
// [new]
// | Create
// v
// +----------------------------------------------------------------+
// | mInUseEntries |
// +------+------------------------------+--------------------------+
// | ^ | Start waiting for
// | | Recycle v
// | | +-----------------------------+
// | | | mPendingEntries |
// | | +--+--------------------+-----+
// | Retain | | Stop waiting for |
// v | v |
// +-------------------+-------------------------+ |
// | mAvailableEntries | |
// +-----------------------------+---------------+ |
// | Evict | Eject
// v v
// [destroyed] [destroyed]
// Each arrow corresponds to one invocation of MutateEntryStorage() with the
// arrow's label passed as the aMutationType string parameter.
// Stores the entries for surfaces that are in use by NativeLayerCA, i.e. an
// entry is inside mInUseEntries between calls to ObtainSurfaceFromPool()
// and ReturnSurfaceToPool().
std::unordered_map<CFTypeRefPtr<IOSurfaceRef>, SurfacePoolEntry>
// Stores entries which are no longer in use by NativeLayerCA but are still
// in use by the window server, i.e. for which
// IOSurfaceIsInUse(pendingSurfaceEntry.mEntry.mIOSurface.get()) still
// returns true. These entries are checked once per frame inside
// CollectPendingSurfaces(), and returned to mAvailableEntries once the
// window server is done.
nsTArray<PendingSurfaceEntry> mPendingEntries;
// Stores entries which are available for recycling. These entries are not
// in use by a NativeLayerCA or by the window server.
nsTArray<SurfacePoolEntry> mAvailableEntries;
// Keeps weak references to SurfacePoolCAWrapperForGL instances.
// For each GLContext* value (including nullptr), only one wrapper can
// exist at any time. The wrapper keeps a strong reference to us and
// notifies us when it gets destroyed. At that point we can call
// DestroyGLResourcesForContext because we know no other SurfaceHandles for
// that context exist.
std::unordered_map<gl::GLContext*, SurfacePoolCAWrapperForGL*> mWrappers;
size_t mPoolSizeLimit = 0;
struct DepthBufferEntry {
RefPtr<gl::GLContext> mGLContext;
gfx::IntSize mSize;
WeakPtr<gl::DepthAndStencilBuffer> mBuffer;
nsTArray<DepthBufferEntry> mDepthBuffers;
DataMutex<LockedPool> mPool;
// One process-wide instance per (SurfacePoolCA*, GLContext*) pair.
// Keeps the SurfacePool alive, and the SurfacePool has a weak reference to the
// wrapper so that it can ensure that there's only one wrapper for it per
// GLContext* at any time.
struct SurfacePoolCAWrapperForGL {
const RefPtr<SurfacePoolCA> mPool; // non-null
const RefPtr<gl::GLContext> mGL; // can be null
SurfacePoolCAWrapperForGL(SurfacePoolCA* aPool, gl::GLContext* aGL)
: mPool(aPool), mGL(aGL) {}
~SurfacePoolCAWrapperForGL() { mPool->OnWrapperDestroyed(mGL, this); }
// A surface pool handle that is stored on NativeLayerCA and keeps the
// SurfacePool alive.
class SurfacePoolHandleCA final : public SurfacePoolHandle {
SurfacePoolHandleCA* AsSurfacePoolHandleCA() override { return this; }
const auto& gl() { return mPoolWrapper->mGL; }
CFTypeRefPtr<IOSurfaceRef> ObtainSurfaceFromPool(const gfx::IntSize& aSize);
void ReturnSurfaceToPool(CFTypeRefPtr<IOSurfaceRef> aSurface);
Maybe<GLuint> GetFramebufferForSurface(CFTypeRefPtr<IOSurfaceRef> aSurface,
bool aNeedsDepthBuffer);
RefPtr<SurfacePool> Pool() override { return mPoolWrapper->mPool; }
void OnBeginFrame() override;
void OnEndFrame() override;
friend class SurfacePoolCA;
SurfacePoolHandleCA(RefPtr<SurfacePoolCAWrapperForGL>&& aPoolWrapper,
uint64_t aCurrentCollectionGeneration);
~SurfacePoolHandleCA() override;
const RefPtr<SurfacePoolCAWrapperForGL> mPoolWrapper;
DataMutex<uint64_t> mPreviousFrameCollectionGeneration;
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_SurfacePoolCA_h