On Wed, 4 Jun 2025 13:55:06 GMT, Patricio Chilano Mateo
<pchilanom...@openjdk.org> wrote:
>> Johannes Bechberger has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> Fix build
>
> src/hotspot/share/jfr/periodic/sampling/jfrCPUTimeThreadSampler.cpp line 330:
>
>> 328: void JfrCPUSamplerThread::stackwalk_threads_in_native() {
>> 329: ResourceMark rm;
>> 330: MutexLocker tlock(Threads_lock);
>
> What exactly are we guarding against by holding the `Threads_lock`? Seems
> `ThreadsListHandle` should be enough.
You're right.
> src/hotspot/share/jfr/periodic/sampling/jfrCPUTimeThreadSampler.cpp line 584:
>
>> 582: sev.sigev_notify = SIGEV_THREAD_ID;
>> 583: sev.sigev_signo = SIG;
>> 584: sev.sigev_value.sival_ptr = &t;
>
> Why setting the address of `t` which is a local variable here?
Because this is how the API works. You store the location where the timer
should be stored.
See https://www.man7.org/linux/man-pages/man2/timer_create.2.html for more
information.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2126741491
PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2126735519
