1804772 - nsIFrame::GetStartPageValue/nsIFrame::GetEndPageValue are slow with very large page counts with CSS named pages enabled

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect, P2)

Description

[Emily McDonough [:alaskanemily]]

This is the same underlying problem as Bug 1803861. We can fix this by copying over the PageValuesProperty frame property when creating continuations.

We might want to investigate sharing a single PageValues struct for all continuations, or ref-counting the struct and possibly also sharing it for entire subtrees as a followup.

Comment 1

[Emily McDonough [:alaskanemily]]

Attachment: Bug 1804772 - Make nsIFrame::GetStartPageValue/nsIFrame::GetEndPageValue constant complexity by copying over the PageValuesProperty value when creating frame continuations.

This was causing layout/generic/crashtests/1683126.html to timeout with named
pages enabled.

It is possible for a frame's PageValues struct to have both the start and end
values be set to null as further children are added. In that case, we can
avoid doing an extra allocation for each of that frame's continuations, as a
small optimization.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4af3a83487c7
Make nsIFrame::GetStartPageValue/nsIFrame::GetEndPageValue constant complexity by copying over the PageValuesProperty value when creating frame continuations. r=dholbert

Comment 3

[Atila Butkovits]

Backed out for causing build bustages at nsCSSFrameConstructor.cpp.

Backout link: https://hg.mozilla.org/integration/autoland/rev/a70682a5774d93c9f14f858736e9df1beed89b85

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=4af3a83487c70770875d39ba7df3e766aa15ecbe&selectedTaskRun=Fcq-oN7VQ96SQnzlXYqR6w.0

Failure log: https://treeherder.mozilla.org/logviewer?job_id=399077276&repo=autoland&lineNumber=22325

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b2fdd07b21f5
Make nsIFrame::GetStartPageValue/nsIFrame::GetEndPageValue constant complexity by copying over the PageValuesProperty value when creating frame continuations. r=dholbert

Comment 5

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/b2fdd07b21f5