RFR: 8348960: [leyden] compiler/c1/TestConcurrentPatching.java is stuck [v3]

[Vladimir Ivanov]

On Fri, 31 Jan 2025 21:40:44 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> This is seen in GHA, and reproduces well on my machine as well:
>> 
>> 
>> $ CONF=linux-x86_64-server-fastdebug make images test TEST=compiler/c1/TestConcurrentPatching.java
>> <stuck, timeout>
>> 
>> 
>> Test runs with `-Xcomp`. gdb "thread apply all bt" shows the compilers are idle. Supplying `-XX:-UseLockFreeCompileQueues` makes the test pass. I believe there is a bug in `UseLockFreeCompileQueues` in leyden repo. 
>> 
>> The comment hopefully explains what happens here. This is a corner case that seems to reproduce on the test that runs `-Xcomp` with a very few compilations.
>> 
>> Additional testing:
>>  - [x] GHA
>>  - [x] Linux x86_64 server fastdebug, `compiler/c1/TestConcurrentPatching.java`, 100x
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Move the fix to CompileTask.get

Looks good.

src/hotspot/share/compiler/compileBroker.cpp line 421:

> 419:   assert(_lock->owned_by_self(), "must own lock");
> 420: 
> 421:   CompileTask* task;

I assume these changes aren't strictly needed (`_queue` is always drained under the lock).

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Marked as reviewed by vlivanov (Committer).

PR Review: https://git.openjdk.org/leyden/pull/30#pullrequestreview-2590609080
PR Review Comment: https://git.openjdk.org/leyden/pull/30#discussion_r1939787326