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locking: Apply contention tracepoints in the slow path

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Adding the lock contention tracepoints in various lock function slow
paths.  Note that each arch can define spinlock differently, I only
added it only to the generic qspinlock for now.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Link: https://lkml.kernel.org/r/20220322185709.141236-3-namhyung@kernel.org
This commit is contained in:
Namhyung Kim 2022-03-22 11:57:09 -07:00 • committed by Peter Zijlstra
parent 16edd9b511
commit ee042be16c
8 changed files with 63 additions and 1 deletions
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7
kernel/locking/rwbase_rt.c
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@ -112,6 +112,8 @@ static int __sched __rwbase_read_lock(struct rwbase_rt *rwb,
* Reader2 to call up_read(), which might be unbound.
*/
trace_contention_begin(rwb, LCB_F_RT | LCB_F_READ);
/*
* For rwlocks this returns 0 unconditionally, so the below
* !ret conditionals are optimized out.
@ -130,6 +132,8 @@ static int __sched __rwbase_read_lock(struct rwbase_rt *rwb,
raw_spin_unlock_irq(&rtm->wait_lock);
if (!ret)
rwbase_rtmutex_unlock(rtm);
trace_contention_end(rwb, ret);
return ret;
}
@ -247,11 +251,13 @@ static int __sched rwbase_write_lock(struct rwbase_rt *rwb,
goto out_unlock;
rwbase_set_and_save_current_state(state);
trace_contention_begin(rwb, LCB_F_RT | LCB_F_WRITE);
for (;;) {
/* Optimized out for rwlocks */
if (rwbase_signal_pending_state(state, current)) {
rwbase_restore_current_state();
__rwbase_write_unlock(rwb, 0, flags);
trace_contention_end(rwb, -EINTR);
return -EINTR;
}
@ -265,6 +271,7 @@ static int __sched rwbase_write_lock(struct rwbase_rt *rwb,
set_current_state(state);
}
rwbase_restore_current_state();
trace_contention_end(rwb, 0);
out_unlock:
raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);