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perf/x86/amd: Rework northbridge event constraints handler

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Code simplification. No functional changes.

Signed-off-by: Robert Richter <rric@kernel.org>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Stephane 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Robert Richter 2013-02-06 11:26:24 -06:00 committed by Ingo Molnar
parent f2b4367a69
commit 2c53c3dd0b
1 changed files with 25 additions and 41 deletions
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66
arch/x86/kernel/cpu/perf_event_amd.c
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@ -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];
}
return &emptyconstraint;
if (new == -1)
return &emptyconstraint;
return &nb->event_constraints[new];
}
static struct amd_nb *amd_alloc_nb(int cpu)