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8254320: Shenandoah: C2 native LRB should activate for non-cset objects #580

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8254320: Shenandoah: C2 native LRB should activate for non-cset objects #580

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rkennke
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@rkennke rkennke commented Oct 9, 2020 •
edited by openjdk bot

In C2 native-LRB, we don't call the slow-path when the reference is not in cset. However, it may need to return NULL for non-cset objects too, in order to prevent accidental ressurrection of referenced object.

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  • JDK-8254320: Shenandoah: C2 native LRB should activate for non-cset objects

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$ git fetch https://git.openjdk.java.net/jdk pull/580/head:pull/580
$ git checkout pull/580

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bridgekeeper bot commented Oct 9, 2020

👋 Welcome back rkennke! 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 openjdk bot added the rfr Pull request is ready for review label Oct 9, 2020
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openjdk bot commented Oct 9, 2020

@rkennke The following labels will be automatically applied to this pull request:

  • hotspot-gc
  • shenandoah

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

@openjdk openjdk bot added hotspot-gc hotspot-gc-dev@openjdk.org shenandoah shenandoah-dev@openjdk.org labels Oct 9, 2020
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mlbridge bot commented Oct 9, 2020 •
edited

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rwestrel
rwestrel approved these changes Oct 12, 2020
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Looks good to me.

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openjdk bot commented Oct 12, 2020 •
edited

@rkennke 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:

8254320: Shenandoah: C2 native LRB should activate for non-cset objects

Reviewed-by: roland, shade

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 22 new commits pushed to the master branch:

  • 295a44a: 8254558: Remove unimplemented Arguments::do_pd_flag_adjustments
  • 0fab73e: 8254560: Shenandoah: Concurrent Strong Roots logging is incorrect
  • 638f910: 8254559: Remove unimplemented JVMFlag::get_locked_message_ext
  • 0ec1d63: 8253117: Replace HTML tables in javadoc summaries with CSS grid elements
  • 54bbe76: 8251544: CTW: C2 fails with assert(no_dead_loop) failed: dead loop detected
  • 13fe054: 8253588: C1: assert(false) failed: unknown register on x86_32 only with -XX:+TraceLinearScanLevel=4
  • 59378a1: 8254164: G1 only removes self forwarding pointers for last collection set increment
  • bf46acf: 8254028: G1 incorrectly updates scan_top for collection set regions during preparation of evacuation
  • a2bb4c6: 8254314: Shenandoah: null checks in c2 should not skip over native load barrier
  • c73a0ff: 8252105: Parallel heap inspection for ZCollectedHeap
  • ... and 12 more: https://git.openjdk.java.net/jdk/compare/52e45a36771641609d8b8531ababe3bfb710ba61...master

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 master branch, type /integrate in a new comment.

@openjdk openjdk bot added the ready Pull request is ready to be integrated label Oct 12, 2020
shipilev
shipilev approved these changes Oct 12, 2020
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A minor documentation nit. Otherwise is fine.

src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
@@ -1342,11 +1342,17 @@ void ShenandoahBarrierC2Support::pin_and_expand(PhaseIdealLoop* phase) {
// Test for in-cset.
// Wires !in_cset(obj) to slot 2 of region and phis
Node* not_cset_ctrl = NULL;
test_in_cset(ctrl, not_cset_ctrl, val, raw_mem, phase);
if (!lrb->is_native()) {
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I think it deserves a comment why LRB-native is special.

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Yup, I added a comment there. Thanks!

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rkennke commented Oct 12, 2020

/integrate

@openjdk openjdk bot closed this Oct 12, 2020
@openjdk openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Oct 12, 2020
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openjdk bot commented Oct 12, 2020

@rkennke Since your change was applied there have been 22 commits pushed to the master branch:

  • 295a44a: 8254558: Remove unimplemented Arguments::do_pd_flag_adjustments
  • 0fab73e: 8254560: Shenandoah: Concurrent Strong Roots logging is incorrect
  • 638f910: 8254559: Remove unimplemented JVMFlag::get_locked_message_ext
  • 0ec1d63: 8253117: Replace HTML tables in javadoc summaries with CSS grid elements
  • 54bbe76: 8251544: CTW: C2 fails with assert(no_dead_loop) failed: dead loop detected
  • 13fe054: 8253588: C1: assert(false) failed: unknown register on x86_32 only with -XX:+TraceLinearScanLevel=4
  • 59378a1: 8254164: G1 only removes self forwarding pointers for last collection set increment
  • bf46acf: 8254028: G1 incorrectly updates scan_top for collection set regions during preparation of evacuation
  • a2bb4c6: 8254314: Shenandoah: null checks in c2 should not skip over native load barrier
  • c73a0ff: 8252105: Parallel heap inspection for ZCollectedHeap
  • ... and 12 more: https://git.openjdk.java.net/jdk/compare/52e45a36771641609d8b8531ababe3bfb710ba61...master

Your commit was automatically rebased without conflicts.

Pushed as commit dfe8ba6.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

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@shipilev shipilev shipilev approved these changes

@rwestrel rwestrel rwestrel approved these changes

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