8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah #6316

zhengyu123 · 2021-11-09T15:08:32Z

JDK-8276205 fixed a bug that prevents concurrent code cache iteration, without holding CodeCache_lock. That causes register_nmethod() calls can go through during concurrent code cache iteration.

This is no a problem for new nmethod, cause it is not in cache cache snapshot for concurrent code cache iteration, but nmethod patching is. We can not allow nmethod patching during concurrent code cache iteration, should block it until iteration is completed.

Test:

hotspot_gc_shenandoah
Stress test on gc/stress/CriticalNativeStress.java

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Issue

JDK-8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah

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Aleksey Shipilev (@shipilev - Reviewer) ⚠️ Review applies to 8e07b34

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bridgekeeper · 2021-11-09T15:09:56Z

👋 Welcome back zgu! 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 · 2021-11-09T15:12:29Z

@zhengyu123 The following labels will be automatically applied to this pull request:

hotspot-gc
shenandoah

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mlbridge · 2021-11-09T16:09:56Z

Webrevs

shipilev · 2021-11-09T16:25:48Z

src/hotspot/share/gc/shenandoah/shenandoahNMethod.cpp

    data->update();
  } else {
+    // For a new nmethod, we can safely append it to the list, cause


Suggested change

// For a new nmethod, we can safely append it to the list, cause

// For a new nmethod, we can safely append it to the list, because

src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp

shipilev

I still do not understand about ShenandoahCodeRoots::unregister_nmethod here. You seem to have restored the assert in the nmethod-table (0248f1e), but surely the assert ShenandoahCodeRoots::unregister_nmethod can also be called at safepoint without CodeCache_lock held?

zhengyu123 · 2021-11-10T13:08:23Z

I still do not understand about ShenandoahCodeRoots::unregister_nmethod here. You seem to have restored the assert in the nmethod-table (0248f1e), but surely the assert ShenandoahCodeRoots::unregister_nmethod can also be called at safepoint without CodeCache_lock held?

It seems possible during STW unloading

I will take a further look in separate CR see if we can cleanup a bit.

shipilev · 2021-11-10T16:57:33Z

I still do not understand about ShenandoahCodeRoots::unregister_nmethod here. You seem to have restored the assert in the nmethod-table (0248f1e), but surely the assert ShenandoahCodeRoots::unregister_nmethod can also be called at safepoint without CodeCache_lock held?

It seems possible during STW unloading

I will take a further look in separate CR see if we can cleanup a bit.

Why further CR, though? I think current code is guaranteed to fail that new assert during STW unloading? If so, we need to keep assert_locked_or_safepoint intact.

zhengyu123 · 2021-11-10T17:10:02Z

I still do not understand about ShenandoahCodeRoots::unregister_nmethod here. You seem to have restored the assert in the nmethod-table (0248f1e), but surely the assert ShenandoahCodeRoots::unregister_nmethod can also be called at safepoint without CodeCache_lock held?

It seems possible during STW unloading
I will take a further look in separate CR see if we can cleanup a bit.

Why further CR, though? I think current code is guaranteed to fail that new assert during STW unloading? If so, we need to keep assert_locked_or_safepoint intact.

Oops, misread you comments. Previous reversion of the assertion was incomplete. Updated.

shipilev

Looks fine.

openjdk · 2021-11-10T17:16:27Z

@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:

8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah

Reviewed-by: 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 46 new commits pushed to the master branch:

ce3ed65: 8273154: Provide a JavadocTester method for non-overlapping, unordered output matching
f561d3c: 8276864: Update boot JDKs to 17.0.1 in GHA
38ec3a1: 8276672: Cannot build hsdis on WSL
55b36c6: 8276825: hotspot/runtime/SelectionResolution test errors
0f23c6a: 8276926: Use String.valueOf() when initializing File.separator and File.pathSeparator
a0b8445: 8276846: JDK-8273416 is incomplete for UseSSE=1
a3f710e: 8276215: Intrinsics matchers should handle native method flags better
0f463a7: 8276845: (fs) java/nio/file/spi/SetDefaultProvider.java fails on x86_32
e01d6d0: 8276679: Malformed Javadoc inline tags in JDK source in javax/swing
fd0a25e: 8276805: java/awt/print/PrinterJob/CheckPrivilege.java fails due to disabled SecurityManager
... and 36 more: https://git.openjdk.java.net/jdk/compare/ff6863c98dbd15c4f3920402eb0991727d1a380c...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.

zhengyu123 · 2021-11-11T00:13:57Z

/integrate

openjdk · 2021-11-11T00:15:02Z

Going to push as commit 73e6d7d.
Since your change was applied there have been 52 commits pushed to the master branch:

bce35ac: 8276775: ZonedDateTime/OffsetDateTime.toString return invalid ISO-8601 for years <= 1893
0c409ca: 8276186: Require getAvailableLocales() methods to include Locale.ROOT
df02daa: 8269986: Remove +3 from Symbol::identity_hash()
2374abd: 8276678: Malformed Javadoc inline tags in JDK source in com/sun/beans/decoder/DocumentHandler.java
67c2714: 8276889: Improve compatibility discussion in instanceKlass.cpp
a5c160c: 8267108: Alternate Subject.getSubject and doAs APIs that do not depend on Security Manager APIs
ce3ed65: 8273154: Provide a JavadocTester method for non-overlapping, unordered output matching
f561d3c: 8276864: Update boot JDKs to 17.0.1 in GHA
38ec3a1: 8276672: Cannot build hsdis on WSL
55b36c6: 8276825: hotspot/runtime/SelectionResolution test errors
... and 42 more: https://git.openjdk.java.net/jdk/compare/ff6863c98dbd15c4f3920402eb0991727d1a380c...master

Your commit was automatically rebased without conflicts.

openjdk · 2021-11-11T00:15:18Z

@zhengyu123 Pushed as commit 73e6d7d.

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

v0

a46bbab

openjdk bot added hotspot-gc hotspot-gc-dev@openjdk.org shenandoah shenandoah-dev@openjdk.org labels Nov 9, 2021

Zhengyu Gu added 2 commits November 9, 2021 10:35

Strength assert

2ec1f12

Consistent assert

aaebcb8

zhengyu123 marked this pull request as ready for review November 9, 2021 16:03

openjdk bot added the rfr Pull request is ready for review label Nov 9, 2021

shipilev reviewed Nov 9, 2021

View reviewed changes

Zhengyu Gu added 2 commits November 9, 2021 12:26

Fix comment as Aleksey suggested

d791ac5

Revert assertion for unregister_nmethod

0248f1e

shipilev suggested changes Nov 10, 2021

View reviewed changes

Fixed incomplete inversion

8e07b34

shipilev approved these changes Nov 10, 2021

View reviewed changes

Reverted wrong method

0a2ef51

openjdk bot added the ready Pull request is ready to be integrated label Nov 10, 2021

openjdk bot closed this Nov 11, 2021

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 Nov 11, 2021

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8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah #6316

8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah #6316

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openjdk bot commented Nov 11, 2021

	// For a new nmethod, we can safely append it to the list, cause
	// For a new nmethod, we can safely append it to the list, because

8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah #6316

8276801: gc/stress/CriticalNativeStress.java fails intermittently with Shenandoah #6316

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