Bug 226122 - [bmalloc] Rollout r276266 because WebKit processes are spending much more time in madvise
Summary: [bmalloc] Rollout r276266 because WebKit processes are spending much more tim...
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Michael Saboff
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2021-05-21 16:26 PDT by Michael Saboff
Modified: 2021-05-21 16:36 PDT (History)
1 user (show)

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Description Michael Saboff 2021-05-21 16:26:37 PDT 
The change for https://bugs.webkit.org/show_bug.cgi?id=224706 causes more calls to madvise.  The way that the bmalloc scavenger calls madvise(..., MADV_FREE_REUSABLE) to decommit ranges is conservative, in that it merges free pages with adjacent free pages.  When we decommit via madvise(), we decommit the whole free range, including pages that have already been decomitted.  Rolling out r276266 to do some automated testing.  At the same time, we'll work on changing the madvise() decommitting to be more precise.

Note that the committing of pages by calling madvise(..., MADV_FREE_REUSE), making them available for bmalloc to use, is precise.  We only call it when are going to use the pages in the range.
Comment 1 Michael Saboff 2021-05-21 16:26:56 PDT 
<rdar://78188389>
Comment 2 Michael Saboff 2021-05-21 16:36:51 PDT 
Committed r277898 (238032@main): <https://commits.webkit.org/238032@main>