RESOLVED FIXED 285620
Revert use of separate megapage heap in libpas 
https://bugs.webkit.org/show_bug.cgi?id=285620
Summary Revert use of separate megapage heap in libpas
David Degazio
Reported Wednesday, January 8, 2025 6:48:16 PM UTC
https://bugs.webkit.org/show_bug.cgi?id=284338 introduced the notion of a megapage large heap per pas_heap, letting us allocate megapages for small/medium objects out of a distinct space from other large objects. Unfortunately this seems to have regressed HashSet-wasm startup in JetStream 2 by 10-20%, seemingly just due to the additional page faults we get from setting up these new heaps. Let's revert this for now, but add a profiling hook to measure how often this happens to revisit enabling this in the future.
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Radar WebKit Bug Importer
Comment 1 Wednesday, January 8, 2025 6:48:27 PM UTC
<rdar://problem/142561181>
David Degazio
Comment 2 Wednesday, January 8, 2025 7:04:48 PM UTC
Pull request: https://github.com/WebKit/WebKit/pull/38737
EWS
Comment 3 Wednesday, January 8, 2025 10:16:10 PM UTC
Committed 288613@main (6bed96b90169): <https://commits.webkit.org/288613@main> Reviewed commits have been landed. Closing PR #38737 and removing active labels.
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