Wasmtime GitHub notifications bot (Feb 16 2022 at 22:25): Wasmtime GitHub notifications bot (Feb 16 2022 at 22:25):alexcrichton opened PR #3819 from less-memory-on-compile to main:
Previously memfd-based image construction had a hard limit of a 1GB
memory image but this mean that tiny wasm modules could allocate up to
1GB of memory which became a bit excessive especially in terms of memory
usage during fuzzing. To fix this the conversion to a static memory
image has been updated to first do a conversion to paged memory
initialization, which is sparse, followed by a second conversion to
static memory initialization.The sparse construction for the paged step should make it such that the
upper/lower bounds of the initialization image are easily computed, and
then afterwards this limit can be checked against some heuristics to
determine if we're willing to commit to building up a whole static image
for that module. The heuristics have been tweaked from "must be less
than 1GB" to one of two conditions must be true:
Either the total memory image size is at most twice the size of the
original paged data itself.Otherwise the memory image size must be smaller than a reasonable
threshold, currently 1MB.We'll likely need to tweak this over time and it's still possible to
cause a lot of extra memory consumption, but for now this should be
enough to appease the fuzzers.Closes #3815
<!--
Please ensure that the following steps are all taken care of before submitting
the PR.
[ ] This has been discussed in issue #..., or if not, please tell us why
here.[ ] A short description of what this does, why it is needed; if the
description becomes long, the matter should probably be discussed in an issue
first.[ ] This PR contains test cases, if meaningful.
- [ ] A reviewer from the core maintainer team has been assigned for this PR.
If you don't know who could review this, please indicate so. The list of
suggested reviewers on the right can help you.Please ensure all communication adheres to the code of conduct.
-->
Wasmtime GitHub notifications bot (Feb 16 2022 at 23:08):cfallin submitted PR review.
Wasmtime GitHub notifications bot (Feb 16 2022 at 23:08):cfallin submitted PR review.
Wasmtime GitHub notifications bot (Feb 16 2022 at 23:08):cfallin created PR review comment:
Constant for this?
Wasmtime GitHub notifications bot (Feb 16 2022 at 23:08):cfallin created PR review comment:
s/theortetically/theoretically/
Wasmtime GitHub notifications bot (Feb 17 2022 at 15:33):alexcrichton updated PR #3819 from less-memory-on-compile to main.
Wasmtime GitHub notifications bot (Feb 17 2022 at 16:37):alexcrichton merged PR #3819.
Last updated: Nov 22 2024 at 16:03 UTC