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Commit 2c53c3dd authored by Robert Richter's avatar Robert Richter Committed by Ingo Molnar
Browse files

perf/x86/amd: Rework northbridge event constraints handler 



Code simplification. No functional changes.

Signed-off-by: default avatarRobert Richter <rric@kernel.org>
Signed-off-by: default avatarJacob Shin <jacob.shin@amd.com>
Acked-by: default avatarStephane Eranian <eranian@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Robert Richter <rric@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1360171589-6381-2-git-send-email-jacob.shin@amd.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent f2b4367a

arch/x86/kernel/cpu/perf_event_amd.c

+26 −42
Original line number Diff line number Diff line
@@ -256,9 +256,8 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) 
{

	struct hw_perf_event *hwc = &event->hw;

	struct amd_nb *nb = cpuc->amd_nb;

	struct perf_event *old = NULL;

	int max = x86_pmu.num_counters;

	int i, j, k = -1;

	struct perf_event *old;

	int idx, new = -1;



	/*

	 * if not NB event or no NB, then no constraints
@@ -276,48 +275,33 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) 
	 * because of successive calls to x86_schedule_events() from

	 * hw_perf_group_sched_in() without hw_perf_enable()

	 */

	for (i = 0; i < max; i++) {

		/*

		 * keep track of first free slot

		 */

		if (k == -1 && !nb->owners[i])

			k = i;

	for (idx = 0; idx < x86_pmu.num_counters; idx++) {

		if (new == -1 || hwc->idx == idx)

			/* assign free slot, prefer hwc->idx */

			old = cmpxchg(nb->owners + idx, NULL, event);

		else if (nb->owners[idx] == event)

			/* event already present */

			old = event;

		else

			continue;



		if (old && old != event)

			continue;



		/* reassign to this slot */

		if (new != -1)

			cmpxchg(nb->owners + new, event, NULL);

		new = idx;



		/* already present, reuse */

		if (nb->owners[i] == event)

			goto done;

	}

	/*

	 * not present, so grab a new slot

	 * starting either at:

	 */

	if (hwc->idx != -1) {

		/* previous assignment */

		i = hwc->idx;

	} else if (k != -1) {

		/* start from free slot found */

		i = k;

	} else {

		/*

		 * event not found, no slot found in

		 * first pass, try again from the

		 * beginning

		 */

		i = 0;

	}

	j = i;

	do {

		old = cmpxchg(nb->owners+i, NULL, event);

		if (!old)

		if (old == event)

			break;

		if (++i == max)

			i = 0;

	} while (i != j);

done:

	if (!old)

		return &nb->event_constraints[i];

	}



	if (new == -1)

		return &emptyconstraint;



	return &nb->event_constraints[new];

}



static struct amd_nb *amd_alloc_nb(int cpu)