On Wed, 4 Jun 2025 17:39:38 GMT, Markus Grönlund <mgron...@openjdk.org> wrote:
>> Johannes Bechberger has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> Readd lock
>
> src/hotspot/share/jfr/periodic/sampling/jfrCPUTimeThreadSampler.cpp line 300:
>
>> 298: if (!Atomic::cmpxchg(&_disenrolled, false, true)) {
>> 299: log_trace(jfr)("Disenrolling CPU thread sampler");
>> 300: if (Atomic::fetch_then_and(&_signal_handler_installed, false)) {
>
> fetch_then_and with false? Must be simpler way to express this? Like
> Atomic::load(&_signal_handler_installed)?
I also want to set it. Wanted to do a simple ::xchg, but this doesn't exist for
booleans.
> src/hotspot/share/jfr/periodic/sampling/jfrCPUTimeThreadSampler.cpp line 608:
>
>> 606: void JfrCPUSamplerThread::stop_signal_handlers() {
>> 607: // set the stop signal bit
>> 608: Atomic::or_then_fetch(&_active_signal_handlers, STOP_SIGNAL_BIT,
>> memory_order_acq_rel);
>
> Whatever was fetched is gone with the wind...
I didn't find an Atomic::or method
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2127120548
PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2127122509
