Stream: git-wasmtime

Topic: wasmtime / PR #3757 memfd: Reduce some syscalls in the on...

Wasmtime GitHub notifications bot (Feb 02 2022 at 21:09):

alexcrichton opened PR #3757 from less-mprotect to main:

This tweaks the internal organization of the MemFdSlot to avoid some
syscalls in the default case as well as opportunistically in the pooling
case. The two cases added here are:

• A MemFdSlot is now created with a specified initial size. For
  pooling this is 0 but for the on-demand case this can be non-zero.

• When instantiate is called with no prior image and the sizes match
  (as will be the case for on-demand allocation) then mprotect is
  skipped entirely.

• In the clear_and_remain-ready case the mprotect is skipped if the
  heap wasn't grown at all.

This should avoid ever using mprotect unnecessarily and makes the
ranges we mprotect a bit smaller as well.

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Wasmtime GitHub notifications bot (Feb 02 2022 at 21:09):

alexcrichton requested cfallin for a review on PR #3757.

Wasmtime GitHub notifications bot (Feb 02 2022 at 21:13):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Feb 02 2022 at 21:13):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Feb 02 2022 at 21:13):

cfallin created PR review comment:

s/should be of have/should have/

Wasmtime GitHub notifications bot (Feb 02 2022 at 21:19):

alexcrichton updated PR #3757 from less-mprotect to main.

Wasmtime GitHub notifications bot (Feb 02 2022 at 22:09):

alexcrichton merged PR #3757.

Last updated: Dec 06 2025 at 06:05 UTC