Re: [PATCH v2] s390/rwlock: Add contention tracepoints to rwlock slowpath

[sashiko-bot@kernel.org]

> Instrument arch_read_lock_wait() and arch_write_lock_wait() with
> trace_contention_begin() and trace_contention_end().
> 
> These tracepoints are used by lock contention analysis tools such as
> perf lock contention to identify contended rwlocks and measure wait
> times. The generic implementation in kernel/locking/qrwlock.c already
> emits the same events from its read and write slowpaths.
> 
> For arch_read_lock_wait(), the in_interrupt() fast-path is intentionally
> left outside the tracepoint scope. That path spins without entering the
> wait queue, so it does not represent queue-based contention and its
> duration is not comparable to the normal slowpath. This matches the
> behaviour of queued_read_lock_slowpath() in qrwlock.c.
> 
> The include for <trace/events/lock.h> is already present from
> commit ffa796cc1f45 ("s390/spinlock: Add contention tracepoints to
> lock slowpath").
> 
> Signed-off-by: Jan Polensky <japo@linux.ibm.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260908135843.1384367-1-japo@linux.ibm.com?part=1