[webkit-changes] [WebKit/WebKit] b7a8c3: DisplayList::ItemBuffer wastes a lot of vector cap...

[Simon Fraser]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: b7a8c3d2ff8941fbd9204e941c71212866492697
      https://github.com/WebKit/WebKit/commit/b7a8c3d2ff8941fbd9204e941c71212866492697
  Author: Simon Fraser <simon.fraser at apple.com>
  Date:   2023-02-04 (Sat, 04 Feb 2023)

  Changed paths:
    M Source/WebCore/platform/graphics/displaylists/DisplayListItemBuffer.h

  Log Message:
  -----------
  DisplayList::ItemBuffer wastes a lot of vector capacity
https://bugs.webkit.org/show_bug.cgi?id=251700
<rdar://problem/105011333>

Reviewed by Wenson Hsieh.

The Vector<ItemBufferHandle, 2> ItemBuffer::m_readOnlyBuffers gets allocated for every GlyphDisplayListCache
entry, but is never used there. It's also very rarely used with GPU process rendering (I never saw use of
m_readOnlyBuffers running MotionMark), so give it default capacity 0, and capacity 2 when it does get allocated.

* Source/WebCore/platform/graphics/displaylists/DisplayListItemBuffer.h:

Canonical link: https://commits.webkit.org/259861@main