8265148: StackWatermarkSet being updated during AsyncGetCallTrace by lmesnik · Pull Request #4217 · openjdk/jdk

lmesnik · 2021-05-27T04:01:17Z

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JDK-8265148: StackWatermarkSet being updated during AsyncGetCallTrace

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Stefan Karlsson (@stefank - Reviewer)
Erik Österlund (@fisk - Reviewer)

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bridgekeeper · 2021-05-27T04:02:06Z

👋 Welcome back lmesnik! 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 · 2021-05-27T04:03:58Z

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

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lmesnik · 2021-05-27T20:15:26Z

I verified that running sunflow with async-profiler crashed VM before the fix and finished successfully after the fix. I compared data for G1GC for older JDK before https://bugs.openjdk.java.net/browse/JDK-8253180 is implemented. The results look pretty similar.

mlbridge · 2021-05-27T20:20:22Z

Webrevs

00: Full (a4bd07d9)

dholmes-ora

Hi Leonid,

Someone familiar with Stackwatermarks will need to comment about the validity of doing this, my only comment is to document why it is being turned off.

Thanks,
David

dholmes-ora · 2021-05-27T23:07:02Z

src/hotspot/share/prims/forte.cpp

    int loop_count;
    int loop_max = MaxJavaStackTraceDepth * 2;
-    RegisterMap map(thread, false);
+    RegisterMap map(thread, false, false);


Can we add some comments as to what the false parameters mean please.

RegisterMap map(thread, false /* no update */, false /*no stackwatermark frame processing */);

Though it may be that a more elaborate block comment is needed to explain why we don't want stackwatermark frame processing.

Let me check with Erik if it makes sense to put more generic comments about the usage of stackwatermark frame processing in RegisterMap, frames etc. They can't be updated in an arbitrary thread state. It makes sense describe this info in stackwatermarking.

Let me check with Erik if it makes sense to put more generic comments about the usage of stackwatermark frame processing in RegisterMap, frames etc. They can't be updated in an arbitrary thread state. It makes sense describe this info in stackwatermarking.

You could say something generic like "StackWatermark can only be used when at points where the stack can be parsed by the GC", or something like that.

Thank you for your prompt response. I meant that it makes sense to update comments for RegisterMap to mention this. Currently, the doc says how to use it and how to disable update:
"Updating of the RegisterMap can be turned off by instantiating the
// register map as: RegisterMap map(thread, false);"
But it says nothing about why and how process_frames should be set.
It might make sense to put this info there so anyone could easily find and read it. I think it is better to put it there rather than in forte.cpp.

Thank you for your prompt response. I meant that it makes sense to update comments for RegisterMap to mention this. Currently, the doc says how to use it and how to disable update:

"Updating of the RegisterMap can be turned off by instantiating the

// register map as: RegisterMap map(thread, false);"

But it says nothing about why and how process_frames should be set.

It might make sense to put this info there so anyone could easily find and read it. I think it is better to put it there rather than in forte.cpp.

Yes I agree - that does make sense.

stefank

Looks good. Could you verify the fix with ZGC? G1 doesn't use it, so testing with G1 will only show that we don't hit the failing assert anymore.

openjdk · 2021-05-28T07:13:17Z

@lmesnik 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:

8265148: StackWatermarkSet being updated during AsyncGetCallTrace

Reviewed-by: stefank, eosterlund

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 24 new commits pushed to the master branch:

0c0ff7f: 8265309: com/sun/jndi/dns/ConfigTests/Timeout.java fails with "Address already in use" BindException
24bf35f: 8265367: [macos-aarch64] 3 java/net/httpclient/websocket tests fail with "IOException: No buffer space available"
1413f9e: 8241423: NUMA APIs fail to work in dockers due to dependent syscalls are disabled by default
1d2c7ac: 8267555: Fix class file version during redefinition after 8238048
97ec5ad: 8265753: Remove manual JavaThread transitions to blocked
6eb9114: 8266877: Missing local debug information when debugging JEP-330
0c9daa7: 8265029: Preserve SIZED characteristics on slice operations (skip, limit)
95b1fa7: 8267529: StringJoiner can create a String that breaks String::equals
7f52c50: 8182043: Access to Windows Large Icons
8a31c07: 8267886: ProblemList javax/management/remote/mandatory/connection/RMIConnector_NPETest.java
... and 14 more: https://git.openjdk.java.net/jdk/compare/6ffa3e66db55774673ce17be4f8f2d510abf8a84...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.

fisk

Looks good, but please test with ZGC before integrating.

lmesnik · 2021-06-01T02:56:28Z

I verified that async-profiles works with ZGC and data look reasonable.

lmesnik · 2021-06-01T18:05:27Z

/integrate

openjdk · 2021-06-01T18:06:36Z

@lmesnik Since your change was applied there have been 56 commits pushed to the master branch:

64ba2f0: 8265431: Add -fno-delete-null-pointer-checks to clang builds
d4b4cae: 8268023: Improve diagnostic for HandshakeFailureTest
9d8ad2e: 8267990: Revisit some uses of synchronized in the HttpClient API
36dc268: 8268036: ProblemList gtest/AsyncLogGtest.java
74b70a5: 8036580: CHA: improve default method support
20479c3: 8065760: CHA: Improve abstract method support
68f3b3a: 8267807: C2: Downcast receiver to target holder during inlining
1c7c0e1: 8267937: Wrong indentation in G1 gc+phases log for free cset subphases
ffd28c4: 8267947: CI: Preserve consistency between has_subklass() and is_subclass_of()
229a6e2: 8267095: Miscellaneous cleanups in vm.runtime.defmeth tests
... and 46 more: https://git.openjdk.java.net/jdk/compare/6ffa3e66db55774673ce17be4f8f2d510abf8a84...master

Your commit was automatically rebased without conflicts.

Pushed as commit 2b33835.

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

lmesnik added 2 commits May 26, 2021 20:59

8265148: StackWatermarkSet being updated during AsyncGetCallTrace

36573e7

space removed.

a4bd07d

openjdk bot added serviceability serviceability-dev@openjdk.org hotspot hotspot-dev@openjdk.org labels May 27, 2021

lmesnik marked this pull request as ready for review May 27, 2021 20:15

openjdk bot added the rfr Pull request is ready for review label May 27, 2021

dholmes-ora reviewed May 27, 2021

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stefank approved these changes May 28, 2021

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openjdk bot added the ready Pull request is ready to be integrated label May 28, 2021

fisk approved these changes May 28, 2021

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openjdk bot closed this Jun 1, 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 Jun 1, 2021

lmesnik deleted the 8265148 branch June 26, 2021 04:42

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