Fix coalesce and fill

[kdnilsen]

It appears that there was an error in our c&f code that mishandled the case when a filll object bumps up against top, and top aligns with the start of a remembered set card.

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Progress

• [ ] Change must not contain extraneous whitespace
• [ ] Commit message must refer to an issue
• [ ] Change must be properly reviewed (1 review required, with at least 1 Committer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/shenandoah.git pull/414/head:pull/414
$ git checkout pull/414

Update a local copy of the PR:
$ git checkout pull/414
$ git pull https://git.openjdk.org/shenandoah.git pull/414/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 414

View PR using the GUI difftool:
$ git pr show -t 414

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/shenandoah/pull/414.diff

[kdnilsen]

I'm going to leave this as draft until I complete more testing. Publishing now in draft form for collaboration and discussion with other developers.

[bridgekeeper[bot]]

:wave: Welcome back kdnilsen! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk[bot]]

❗ This change is not yet ready to be integrated. See the Progress checklist in the description for automated requirements.

[kdnilsen]

FWIW, I have confirmed that the "problem" workload we have been debugging does emit the message: "KELVIN CONFIRMS PROBLEM"

[openjdk[bot]]

@kdnilsen this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout fix-coalesce-and-fill
git fetch https://git.openjdk.org/shenandoah.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[openjdk[bot]]

⚠️ @kdnilsen This pull request contains merges that bring in commits not present in the target repository. Since this is not a "merge style" pull request, these changes will be squashed when this pull request in integrated. If this is your intention, then please ignore this message. If you want to preserve the commit structure, you must change the title of this pull request to Merge <project>:<branch> where <project> is the name of another project in the OpenJDK organization (for example Merge jdk:master).

[bridgekeeper[bot]]

@kdnilsen This pull request has been inactive for more than 8 weeks and will be automatically closed if another 8 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[bridgekeeper[bot]]

@kdnilsen This pull request has been inactive for more than 16 weeks and will now be automatically closed. If you would like to continue working on this pull request in the future, feel free to reopen it! This can be done using the /open pull request command.