Reset JNI Addresses if FSD on restore (0.48) - #20122
Merged
Merged
Conversation
If debug is specified on restore, ensure that any proactively compiled JNI Methods are reset to their original address. JNI methods are not compiled under FSD, but they are compiled proactively in the checkpoint hook. However, if debug is specified on restore, all proactively compiled methods, except for JNI thunks, get invalidated. Thus, the extra field of the J9Method of a JNI method needs to get reset to whatever the VM initialized them to originally. This is necessary to ensure an environment that is consistent with FSD mode. The invalidation of proactively compiled non-JNI methods (which are non-FSD bodies) ensure that non-FSD code does not execute post-restore. At the checkpoint hook, only FSD bodies are on the stacks of the threads; although the compiler currently does not reuse these FSD bodies, they will continue to execute on restore until an OSR transition, but this is OK because they are already set up for involuntary OSR. The missing piece was the JNI methods, which this commit addresses. Signed-off-by: Irwin D'Souza <dsouzai.gh@gmail.com>
dsouzai
added this to the
Release 0.48 (Java 8, 11, 17, 21, 23) October refresh milestone
Contributor
Author
|
@mpirvu this is the 0.48 backport. fyi @TobiAjila |
Contributor
|
I will wait on this until tomorrow, so that the original fix goes through the nightly testing. |
Contributor
|
I verified that the this change is equivalent to the one in the master branch. |
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
If debug is specified on restore, ensure that any proactively compiled JNI Methods are reset to their original address.
JNI methods are not compiled under FSD, but they are compiled proactively in the checkpoint hook. However, if debug is specified on restore, all proactively compiled methods, except for JNI thunks, get invalidated. Thus, the extra field of the J9Method of a JNI method needs to get reset to whatever the VM initialized them to originally.
This is necessary to ensure an environment that is consistent with FSD mode. The invalidation of proactively compiled non-JNI methods (which are non-FSD bodies) ensure that non-FSD code does not execute post-restore. At the checkpoint hook, only FSD bodies are on the stacks of the threads; although the compiler currently does not reuse these FSD bodies, they will continue to execute on restore until an OSR transition, but this is OK because they are already set up for involuntary OSR. The missing piece was the JNI methods, which this commit addresses.
cherry-pick of #20108 (with a merge conflict fixed).