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perf/x86/intel: Simplify put_exclusive_constraints()

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Don't bother with taking locks if we're not actually going to do
anything. Also, drop the _irqsave(), this is very much only called
from IRQ-disabled context.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2015-05-22 11:36:13 +02:00 committed by Ingo Molnar
parent 8736e548db
commit ba040653b4
1 changed files with 15 additions and 14 deletions
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29
arch/x86/kernel/cpu/perf_event_intel.c
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@ -2130,7 +2130,6 @@ static void intel_put_excl_constraints(struct cpu_hw_events *cpuc,
struct intel_excl_cntrs *excl_cntrs = cpuc->excl_cntrs;
int tid = cpuc->excl_thread_id;
struct intel_excl_states *xl;
unsigned long flags = 0; /* keep compiler happy */
/*
* nothing needed if in group validation mode
@ -2141,7 +2140,6 @@ static void intel_put_excl_constraints(struct cpu_hw_events *cpuc,
if (WARN_ON_ONCE(!excl_cntrs))
return;
xl = &excl_cntrs->states[tid];
if (hwc->flags & PERF_X86_EVENT_EXCL_ACCT) {
hwc->flags &= ~PERF_X86_EVENT_EXCL_ACCT;
if (!--cpuc->n_excl)
@ -2149,22 +2147,25 @@ static void intel_put_excl_constraints(struct cpu_hw_events *cpuc,
}
/*
* put_constraint may be called from x86_schedule_events()
* which already has the lock held so here make locking
* conditional
* If event was actually assigned, then mark the counter state as
* unused now.
*/
if (!xl->sched_started)
raw_spin_lock_irqsave(&excl_cntrs->lock, flags);
if (hwc->idx >= 0) {
xl = &excl_cntrs->states[tid];
/*
* put_constraint may be called from x86_schedule_events()
* which already has the lock held so here make locking
* conditional.
*/
if (!xl->sched_started)
raw_spin_lock(&excl_cntrs->lock);
/*
* if event was actually assigned, then mark the
* counter state as unused now
*/
if (hwc->idx >= 0)
xl->state[hwc->idx] = INTEL_EXCL_UNUSED;
if (!xl->sched_started)
raw_spin_unlock_irqrestore(&excl_cntrs->lock, flags);
if (!xl->sched_started)
raw_spin_unlock(&excl_cntrs->lock);
}
}
static void