8255765: Shenandoah: Isolate concurrent, degenerated and full GC #1964
Conversation
…JDK-8255019-sh-mark
|
@zhengyu123 this pull request can not be integrated into git checkout JDK-8255765-isolate-gcs
git fetch https://git.openjdk.java.net/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push |
openjdk
bot
added
the
merge-conflict
openjdk
bot
removed
the
merge-conflict
Webrevs
|
|
@shipilev should also look at this. |
|
@zhengyu123 This change now passes all automated pre-integration checks. ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details. After integration, the commit message for the final commit will be: You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed. At the time when this comment was updated there had been 31 new commits pushed to the
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details. ➡️ To integrate this PR with the above commit message to the |
|
/integrate |
openjdk
bot
added
integrated
|
@zhengyu123 Since your change was applied there have been 31 commits pushed to the
Your commit was automatically rebased without conflicts. Pushed as commit 34eb8b3. 💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored. |
The purpose of this patch is to isolate concurrent, degenerated and full gc implementation, so that, makes each GC implementation more straightforward and clean, and improves readability.
Current implementation emphasis code sharing, e.g. degenerated GC reuses concurrent GC's ops. It was not a problem in the beginning, when they actually behave similarly. Since concurrent GC moved root processing into concurrent phases, code started to diverge, we started to put bandages to make the shared ops work for both concurrent and degenerated GC, that made code hard to read and error prone.
The patch breaks up GCs into 3 (mainly just concurrent and degenerated GC, as full GC already standalone) easy to identify and understand classes (ShenandoahConcurrentGC, ShenandoahDegeneratedGC and ShenandoahMarkCompactGC), subclasses of ShenandoahGC class.
The three GCs still keep vmop/entry/op paradigm, but encapsulate GC control flow inside their own classes, as ShenandoahMarkCompact GC already does. So that, concurrent and degenerated GC no longer share ops and op implementations no longer need to consider other GC modes, which results in simplifying implementation and improving readability. Code sharing is achieved via helper methods provided by ShenandoahHeap.
Test:
Progress
Issue
Reviewers
Download
$ git fetch https://git.openjdk.java.net/jdk pull/1964/head:pull/1964$ git checkout pull/1964