[webkit-changes] [WebKit/WebKit] 4d14bf: RemoteImageBufferProxyFlushState::waitForDidFlush...

[mattwoodrow]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 4d14bfb53b47c472855523961299fea0b882c062
      https://github.com/WebKit/WebKit/commit/4d14bfb53b47c472855523961299fea0b882c062
  Author: Matt Woodrow <mattwoodrow at apple.com>
  Date:   2023-05-01 (Mon, 01 May 2023)

  Changed paths:
    M Source/WebKit/GPUProcess/graphics/RemoteDisplayListRecorder.cpp
    M Source/WebKit/GPUProcess/graphics/RemoteDisplayListRecorder.h
    M Source/WebKit/GPUProcess/graphics/RemoteDisplayListRecorder.messages.in
    M Source/WebKit/GPUProcess/graphics/RemoteRenderingBackend.cpp
    M Source/WebKit/GPUProcess/graphics/RemoteRenderingBackend.h
    M Source/WebKit/WebProcess/GPU/graphics/RemoteDisplayListRecorderProxy.cpp
    M Source/WebKit/WebProcess/GPU/graphics/RemoteDisplayListRecorderProxy.h
    M Source/WebKit/WebProcess/GPU/graphics/RemoteImageBufferProxy.cpp
    M Source/WebKit/WebProcess/GPU/graphics/RemoteImageBufferProxy.h
    M Source/WebKit/WebProcess/GPU/graphics/RemoteRenderingBackendProxy.cpp
    M Source/WebKit/WebProcess/GPU/graphics/RemoteRenderingBackendProxy.h
    M Source/WebKit/WebProcess/GPU/graphics/RemoteRenderingBackendProxy.messages.in

  Log Message:
  -----------
   RemoteImageBufferProxyFlushState::waitForDidFlushOnSecondaryThread blocks on a task running on the main thread.
https://bugs.webkit.org/show_bug.cgi?id=256073
<rdar://108642579>

Reviewed by Simon Fraser.

We attempt to wait for flushes of RemoteImageBufferProxy on a background thread, but the 'didFlush' IPC message is received on the main thread.

This can mean it gets delayed (and we don't know the flush is completed) if the main thread is otherwise busy. This delays first-paint on CPLT.

This change passes a Semphore across to the GPUP instead of the flush identifier, and we signal it when the flush is completed rather than sending a return 'didFlush' message.
The WebProcess waits on each flush Semaphore in a background WorkQueue, and then processes the equivalent of 'didFlush' asynchronously and notifies the condition variable to wake any waiting threads.

waitForDidFlushWithTimeout is removed, and all waiters now use the waitForDidFlushOnSecondaryThread code path (renamed) since all waiters are now 'secondary' WRT the flushing WorkQueue.

Synchronous flushes now use a proper synchronous IPC message, rather than relying on async + wait.

* Source/WebKit/GPUProcess/graphics/RemoteDisplayListRecorder.cpp:
(WebKit::RemoteDisplayListRecorder::flushContext):
(WebKit::RemoteDisplayListRecorder::flushContextSync):
* Source/WebKit/GPUProcess/graphics/RemoteDisplayListRecorder.h:
* Source/WebKit/GPUProcess/graphics/RemoteDisplayListRecorder.messages.in:
* Source/WebKit/GPUProcess/graphics/RemoteRenderingBackend.cpp:
(WebKit::RemoteRenderingBackend::didFlush): Deleted.
* Source/WebKit/GPUProcess/graphics/RemoteRenderingBackend.h:
* Source/WebKit/WebProcess/GPU/graphics/RemoteDisplayListRecorderProxy.cpp:
(WebKit::RemoteDisplayListRecorderProxy::sendSync):
(WebKit::RemoteDisplayListRecorderProxy::flushContext):
(WebKit::RemoteDisplayListRecorderProxy::flushContextSync):
* Source/WebKit/WebProcess/GPU/graphics/RemoteDisplayListRecorderProxy.h:
* Source/WebKit/WebProcess/GPU/graphics/RemoteImageBufferProxy.cpp:
(WebKit::RemoteImageBufferProxy::flushDrawingContext):
(WebKit::RemoteImageBufferProxy::flushDrawingContextAsync):
(WebKit::RemoteImageBufferProxyFlushState::waitForDidFlush):
(WebKit::RemoteImageBufferProxy::waitForDidFlushWithTimeout): Deleted.
(WebKit::RemoteImageBufferProxyFlushState::waitForDidFlushOnSecondaryThread): Deleted.
* Source/WebKit/WebProcess/GPU/graphics/RemoteImageBufferProxy.h:
* Source/WebKit/WebProcess/GPU/graphics/RemoteRenderingBackendProxy.cpp:
(WebKit::RemoteRenderingBackendProxy::RemoteRenderingBackendProxy):
(WebKit::RemoteRenderingBackendProxy::disconnectGPUProcess):
(WebKit::RemoteRenderingBackendProxy::addPendingFlush):
(WebKit::RemoteRenderingBackendProxy::waitForDidFlush): Deleted.
(WebKit::RemoteRenderingBackendProxy::didFlush): Deleted.
* Source/WebKit/WebProcess/GPU/graphics/RemoteRenderingBackendProxy.h:
* Source/WebKit/WebProcess/GPU/graphics/RemoteRenderingBackendProxy.messages.in:

Canonical link: https://commits.webkit.org/263572@main