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Commit ba040653 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf/x86/intel: Simplify put_exclusive_constraints() 



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: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 8736e548

arch/x86/kernel/cpu/perf_event_intel.c

+15 −14
Original line number Diff line number Diff line
@@ -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
@@ -2141,30 +2140,32 @@ 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)

			WRITE_ONCE(excl_cntrs->has_exclusive[tid], 0);

	}



	/*

	 * If event was actually assigned, then mark the counter state as

	 * unused now.

	 */

	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

		 * conditional.

		 */

		if (!xl->sched_started)

		raw_spin_lock_irqsave(&excl_cntrs->lock, flags);

			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);

			raw_spin_unlock(&excl_cntrs->lock);

	}

}



static void