Patch qemu in CI to fix madvise semantics.#3770
Merged
cfallin merged 1 commit intobytecodealliance:mainfrom Feb 7, 2022
Merged
Patch qemu in CI to fix madvise semantics.#3770cfallin merged 1 commit intobytecodealliance:mainfrom
cfallin merged 1 commit intobytecodealliance:mainfrom
Conversation
sunfishcode
reviewed
Feb 7, 2022
We currently skip some tests when running our qemu-based tests for aarch64 and s390x. Qemu has broken madvise(MADV_DONTNEED) semantics -- specifically, it just ignores madvise() [1]. We could continue to whack-a-mole the tests whenever we create new functionality that relies on madvise() semantics, but ideally we'd just have emulation that properly emulates! The earlier discussions on the qemu mailing list [2] had a proposed patch for this, but (i) this patch doesn't seem to apply cleanly anymore (it's 3.5 years old) and (ii) it's pretty complex due to the need to handle qemu's ability to emulate differing page sizes on host and guest. It turns out that we only really need this for CI when host and guest have the same page size (4KiB), so we *could* just pass the madvise()s through. I wouldn't expect such a patch to ever land upstream in qemu, but it satisfies our needs I think. So this PR modifies our CI setup to patch qemu before building it locally with a little one-off patch. [1] bytecodealliance#2518 (comment) [2] https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg05416.html
mpardesh
pushed a commit
to avanhatt/wasmtime
that referenced
this pull request
Mar 17, 2022
We currently skip some tests when running our qemu-based tests for aarch64 and s390x. Qemu has broken madvise(MADV_DONTNEED) semantics -- specifically, it just ignores madvise() [1]. We could continue to whack-a-mole the tests whenever we create new functionality that relies on madvise() semantics, but ideally we'd just have emulation that properly emulates! The earlier discussions on the qemu mailing list [2] had a proposed patch for this, but (i) this patch doesn't seem to apply cleanly anymore (it's 3.5 years old) and (ii) it's pretty complex due to the need to handle qemu's ability to emulate differing page sizes on host and guest. It turns out that we only really need this for CI when host and guest have the same page size (4KiB), so we *could* just pass the madvise()s through. I wouldn't expect such a patch to ever land upstream in qemu, but it satisfies our needs I think. So this PR modifies our CI setup to patch qemu before building it locally with a little one-off patch. [1] bytecodealliance#2518 (comment) [2] https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg05416.html
Closed
2 tasks
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
We currently skip some tests when running our qemu-based tests for
aarch64 and s390x. Qemu has broken madvise(MADV_DONTNEED) semantics --
specifically, it just ignores madvise() [1].
We could continue to whack-a-mole the tests whenever we create new
functionality that relies on madvise() semantics, but ideally we'd just
have emulation that properly emulates!
The earlier discussions on the qemu mailing list [2] had a proposed
patch for this, but (i) this patch doesn't seem to apply cleanly anymore
(it's 3.5 years old) and (ii) it's pretty complex due to the need to
handle qemu's ability to emulate differing page sizes on host and guest.
It turns out that we only really need this for CI when host and guest
have the same page size (4KiB), so we could just pass the madvise()s
through. I wouldn't expect such a patch to ever land upstream in qemu,
but it satisfies our needs I think. So this PR modifies our CI setup to
patch qemu before building it locally with a little one-off patch.
[1]
#2518 (comment)
[2]
https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg05416.html