commit 064ec1ba73635e352dedfbcc0ab993b0c4369fa4
author Morten Stenshorne <mstensho@chromium.org> Wed Aug 16 21:06:05 2023
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Aug 16 21:06:05 2023
tree 633a0faa39844851926234e5a8495f35c961744b
parent 3426bf6e8f2eb618d09608b4379ee73f2c4c31a9

Skip fragment item pre-allocation inside block fragmentation.

When in block fragmentation (and the fragmentainer size is known), we'd
greatly over-estimate the number of fragment items to be added to the
builder.

This lead to an out-of-memory situation, presumably because oilpan
didn't get around to collecting all the large temporary buffers before
it was too late (at least one such buffer would be allocated per
fragmentainer).

The test included is just a perf test, which is about 3.5 times faster
than before. Writing a test that would crash without this fix would be
super-slow also with the fix included, so this is the best we can do, as
far as I can tell.

Bug: 1471849
Change-Id: I3c1c2757349da9508657984b7d371f9243f5809b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4782829
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1184376}