Bug 220126 – [GPU Process]: Don't call flushDrawingContext() in the middle of recording drawing commands

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Said Abou-Hallawa]

Before using a single shared memory buffer for sending the DL items from WebP to GPUP, calling flushDrawingContext() was necessary to synchronize multiple ImageBuffers drawing. The single shared memory buffer guarantees the order of drawing is preserved even when an ImageBuffer is drawn into another ImageBuffer. So flushDrawingContext() should be called only when the drawing is finished and the backend of the ImageBuffer is about to be used.

[Said Abou-Hallawa]

<rdar://problem/72394086>

[Said Abou-Hallawa]

Created attachment 416720 [details]
Patch

[Wenson Hsieh]

Comment on attachment 416720 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=416720&action=review

> Source/WebCore/ChangeLog:8
> +        Avoid calling lushDrawingContext() except when the drawing is finished

Nit - flushDrawingContext()

> Source/WebCore/platform/graphics/displaylists/DisplayListRecorder.cpp:-185
> -    imageBuffer.flushDrawingContext();

Just to confirm — we don't need to call CGContextFlush for the previous canvas's remote image buffer either?

> Source/WebKit/WebProcess/GPU/graphics/RemoteImageBufferProxy.h:-387
> -    size_t m_itemCountInCurrentDisplayList { 0 };

Nice.

[Simon Fraser (smfr)]

Comment on attachment 416720 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=416720&action=review

>> Source/WebCore/platform/graphics/displaylists/DisplayListRecorder.cpp:-185
>> -    imageBuffer.flushDrawingContext();
> 
> Just to confirm — we don't need to call CGContextFlush for the previous canvas's remote image buffer either?

CG should take care of flushing when drawing one IOSurface-based CGContext into another.

[Said Abou-Hallawa]

Created attachment 416722 [details]
Patch

[Said Abou-Hallawa]

*** Bug 219558 has been marked as a duplicate of this bug. ***

[EWS]

Committed r271079: <https://trac.webkit.org/changeset/271079>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 416722 [details].