Image.h

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Hash : 36c3e0f5
Author :
Date : 2023-01-17T17:42:59

Implement "Shared Context Mutex" functionality.

Existing implementation uses single `GlobalMutex` for
- EGL calls
- GL calls for Contexts with concurrent access.

This CL introduces abstract `egl::ContextMutex` with two
implementations:
- SingleContextMutex;
- SharedContextMutex<Mutex>;

Note:
`std::mutex` is used in this commit. It is very easy to change mutex
type either at compile-time or at run-time (single type per Display).

When Context:
- is not Shared;
- does not use `EGLImage`s;
- does not use EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE
- does not use EGL_DISPLAY_SEMAPHORE_SHARE_GROUP_ANGLE
then it will be using `SingleContextMutex` with minimal overhead.

Before such Context is used as `shareContext` or uses `EGLImage`
its mutex replaced by `SharedContextMutex<Mutex>`.

The `GlobalMutex` is only used for EGL calls, while `egl::ContextMutex`
implementations for GL calls. Because some EGL calls use Context,
explicit `egl::ContextMutex` lock is required. This is implemented by
generating "egl_context_mutex_autogen.h" header, and insertion of
`ANGLE_EGL_SCOPED_CONTEXT_LOCK()` macro before `ANGLE_EGL_VALIDATE()`
in each EGL entry point. Implementation in "egl_context_lock_impl.h"
returns lock for required APIs. Special cases of `egl::ContextMutex`
lock handled separately. `std::unique_lock<>` is not used for
performance reasons.

`egl::ContextMutex` explicitly locked when capturing EGL calls.

Fixes EGLImage problem:
https://chromium.googlesource.com/angle/angle/+/e18240d136d15e5cdfa4fa4a6355ca21c8d807b6
Mark contexts as shared when importing EGL images.

Details:
- EGLImage inherits Context's mutex when created.
Mutex is used when the EGLImage accessed or destroyed.
- When EGLImage is used in Context with other `egl::ContextMutex`,
two mutexes are merged into one.
- After the mutex merge, Context Groups will remain separate,
but will not be able to run in parallel.

Fixes race when checking `context->isShared()` in the
`SCOPED_SHARE_CONTEXT_LOCK()` macro. One Context may start executing GL
call while not "Shared", but become "Shared" inside the call. New
(second) "Shared" Context may immediately start using GL and potentially
corrupt some "Shared" state.

Possible performance benefit: allows parallel execution in some cases,
when single `GlobalMutex` would block.

Important note:
Process of replacing the `SingleContextMutex` by
`SharedContextMutex<Mutex>` is not 100% safe. This mean that
original Context may still be using `SingleContextMutex` after
activating `SharedContextMutex<Mutex>`. However, this was always
the case before introduction of this CL. Old `Context::mShared`
member update was not synchronized in any way at all. In other
words, this solution does not 100% fix the original problem.
For 100% safe solution `SingleContextMutex` should not be used
(always pass `SharedContextMutex<Mutex>` to the `gl::Context`
constructor). See `lockAndActivateSharedContextMutex()` for more
details.

CL adds new build option:
angle_enable_shared_context_mutex = true

Behavior with other build options:
- When:
`angle_enable_shared_context_mutex` is disabled or
`angle_enable_share_context_lock` is disabled or
`angle_force_context_check_every_call` is enabled,
Contexts will always have `SingleContextMutex`, however it will be
only used in special cases. `SCOPED_SHARE_CONTEXT_LOCK()` will use
`GlobalMutex` when applicable.
- Otherwise, `SCOPED_SHARE_CONTEXT_LOCK()` will use `egl::ContextMutex`.

Some GFXBench "1080p Driver Overhead 2 Offscreen" performance numbers.
Tested on S906B (Samsung Galaxy S22+) on old ANGLE base:
https://chromium.googlesource.com/angle/angle/+/807c94ea85e046c6f279d081d99f0fb1bcf1191a
Capture/Replay: Adjust tests do adhere to capture limits

Each test result is an average frame number from 6 runs.

SingleContextMutex 6579 ( +0.13%)
(old) GetContextLock() (mShared is false) 6570

Forced `mShared = true` or NOT using `SingleContextMutex`.

SharedContextMutex<std::mutex> FORCE 5061 (-22.97%)
(old) GetContextLock() FORCE 4766 (-27.46%)

Bug: angleproject:6957
Bug: chromium:1336126
Change-Id: Idcd919f9d4bf482b9ae489bd8b4415ec96048e32
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4374545
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

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src/libANGLE/Image.h

//
// Copyright 2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// Image.h: Defines the egl::Image class representing the EGLimage object.

#ifndef LIBANGLE_IMAGE_H_
#define LIBANGLE_IMAGE_H_

#include "common/FastVector.h"
#include "common/angleutils.h"
#include "libANGLE/AttributeMap.h"
#include "libANGLE/Debug.h"
#include "libANGLE/Error.h"
#include "libANGLE/FramebufferAttachment.h"
#include "libANGLE/RefCountObject.h"
#include "libANGLE/formatutils.h"

namespace rx
{
class EGLImplFactory;
class ImageImpl;
class ExternalImageSiblingImpl;

// Used for distinguishing dirty bit messages from gl::Texture/rx::TexureImpl/gl::Image.
constexpr size_t kTextureImageImplObserverMessageIndex = 0;
constexpr size_t kTextureImageSiblingMessageIndex      = 1;
}  // namespace rx

namespace egl
{
class Image;
class Display;
class ContextMutex;

// Only currently Renderbuffers and Textures can be bound with images. This makes the relationship
// explicit, and also ensures that an image sibling can determine if it's been initialized or not,
// which is important for the robust resource init extension with Textures and EGLImages.
class ImageSibling : public gl::FramebufferAttachmentObject
{
  public:
    ImageSibling();
    ~ImageSibling() override;

    bool isEGLImageTarget() const;
    gl::InitState sourceEGLImageInitState() const;
    void setSourceEGLImageInitState(gl::InitState initState) const;

    bool isRenderable(const gl::Context *context,
                      GLenum binding,
                      const gl::ImageIndex &imageIndex) const override;
    bool isYUV() const override;
    bool isExternalImageWithoutIndividualSync() const override;
    bool hasFrontBufferUsage() const override;
    bool hasProtectedContent() const override;

  protected:
    // Set the image target of this sibling
    void setTargetImage(const gl::Context *context, egl::Image *imageTarget);

    // Orphan all EGL image sources and targets
    angle::Result orphanImages(const gl::Context *context,
                               RefCountObjectReleaser<Image> *outReleaseImage);

    void notifySiblings(angle::SubjectMessage message);

  private:
    friend class Image;

    // Called from Image only to add a new source image
    void addImageSource(egl::Image *imageSource);

    // Called from Image only to remove a source image when the Image is being deleted
    void removeImageSource(egl::Image *imageSource);

    static constexpr size_t kSourcesOfSetSize = 2;
    angle::FlatUnorderedSet<Image *, kSourcesOfSetSize> mSourcesOf;
    BindingPointer<Image> mTargetOf;
};

// Wrapper for EGLImage sources that are not owned by ANGLE, these often have to do
// platform-specific queries for format and size information.
class ExternalImageSibling : public ImageSibling
{
  public:
    ExternalImageSibling(rx::EGLImplFactory *factory,
                         const gl::Context *context,
                         EGLenum target,
                         EGLClientBuffer buffer,
                         const AttributeMap &attribs);
    ~ExternalImageSibling() override;

    void onDestroy(const egl::Display *display);

    Error initialize(const Display *display, const gl::Context *context);

    gl::Extents getAttachmentSize(const gl::ImageIndex &imageIndex) const override;
    gl::Format getAttachmentFormat(GLenum binding, const gl::ImageIndex &imageIndex) const override;
    GLsizei getAttachmentSamples(const gl::ImageIndex &imageIndex) const override;
    GLuint getLevelCount() const;
    bool isRenderable(const gl::Context *context,
                      GLenum binding,
                      const gl::ImageIndex &imageIndex) const override;
    bool isTextureable(const gl::Context *context) const;
    bool isYUV() const override;
    bool hasFrontBufferUsage() const override;
    bool isCubeMap() const;
    bool hasProtectedContent() const override;

    void onAttach(const gl::Context *context, rx::UniqueSerial framebufferSerial) override;
    void onDetach(const gl::Context *context, rx::UniqueSerial framebufferSerial) override;
    GLuint getId() const override;

    gl::InitState initState(GLenum binding, const gl::ImageIndex &imageIndex) const override;
    void setInitState(GLenum binding,
                      const gl::ImageIndex &imageIndex,
                      gl::InitState initState) override;

    rx::ExternalImageSiblingImpl *getImplementation() const;

  protected:
    rx::FramebufferAttachmentObjectImpl *getAttachmentImpl() const override;

  private:
    // ObserverInterface implementation.
    void onSubjectStateChange(angle::SubjectIndex index, angle::SubjectMessage message) override;

    std::unique_ptr<rx::ExternalImageSiblingImpl> mImplementation;
    angle::ObserverBinding mImplObserverBinding;
};

struct ImageState : private angle::NonCopyable
{
    ImageState(ImageID id, EGLenum target, ImageSibling *buffer, const AttributeMap &attribs);
    ~ImageState();

    ImageID id;

    EGLLabelKHR label;
    EGLenum target;
    gl::ImageIndex imageIndex;
    ImageSibling *source;

    gl::Format format;
    bool yuv;
    bool cubeMap;
    gl::Extents size;
    size_t samples;
    GLuint levelCount;
    EGLenum colorspace;
    bool hasProtectedContent;

    mutable std::mutex targetsLock;

    static constexpr size_t kTargetsSetSize = 2;
    angle::FlatUnorderedSet<ImageSibling *, kTargetsSetSize> targets;
};

class Image final : public RefCountObject, public LabeledObject
{
  public:
    Image(rx::EGLImplFactory *factory,
          ImageID id,
          const gl::Context *context,
          EGLenum target,
          ImageSibling *buffer,
          const AttributeMap &attribs);

    void onDestroy(const Display *display) override;
    ~Image() override;

    ImageID id() const { return mState.id; }

    void setLabel(EGLLabelKHR label) override;
    EGLLabelKHR getLabel() const override;

    const gl::Format &getFormat() const;
    bool isRenderable(const gl::Context *context) const;
    bool isTexturable(const gl::Context *context) const;
    bool isYUV() const;
    bool isExternalImageWithoutIndividualSync() const;
    bool hasFrontBufferUsage() const;
    // Returns true only if the eglImage contains a complete cubemap
    bool isCubeMap() const;
    size_t getWidth() const;
    size_t getHeight() const;
    const gl::Extents &getExtents() const;
    bool isLayered() const;
    size_t getSamples() const;
    GLuint getLevelCount() const;
    bool hasProtectedContent() const;

    Error initialize(const Display *display, const gl::Context *context);

    rx::ImageImpl *getImplementation() const;

    bool orphaned() const;
    gl::InitState sourceInitState() const;
    void setInitState(gl::InitState initState);

    Error exportVkImage(void *vkImage, void *vkImageCreateInfo);

    ContextMutex *getSharedContextMutex() const { return mSharedContextMutex; }

  private:
    friend class ImageSibling;

    // Called from ImageSibling only notify the image that a new target sibling exists for state
    // tracking.
    void addTargetSibling(ImageSibling *sibling);

    // Called from ImageSibling only to notify the image that a sibling (source or target) has
    // been respecified and state tracking should be updated.
    angle::Result orphanSibling(const gl::Context *context, ImageSibling *sibling);

    void notifySiblings(const ImageSibling *notifier, angle::SubjectMessage message);

    ImageState mState;
    rx::ImageImpl *mImplementation;
    bool mOrphanedAndNeedsInit;
    bool mIsTexturable = false;
    bool mIsRenderable = false;

    ContextMutex *mSharedContextMutex;  // Reference counted
};
}  // namespace egl

#endif  // LIBANGLE_IMAGE_H_

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