[tip:perf/urgent] perf, x86: Fix x86_pmu_start

tip-bot for Peter Zijlstra
2010-03-10T13:12:52Z

Commit-ID: c08053e627d23490a03431285b78b7a5b617fbad
Gitweb: http://git.kernel.org/tip/c08053e627d23490a03431285b78b7a5b617fbad
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Sat, 6 Mar 2010 13:19:24 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 10 Mar 2010 13:22:30 +0100

perf, x86: Fix x86_pmu_start

pmu::start should undo pmu::stop, make it so.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/perf_event.c | 23 ++++++++++-------------
1 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 01b1667..9757b96 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -785,6 +785,7 @@ static inline int match_prev_assignment(struct hw_perf_event *hwc,
hwc->last_tag == cpuc->tags[i];
}

+static int x86_pmu_start(struct perf_event *event);
static void x86_pmu_stop(struct perf_event *event);

void hw_perf_enable(void)
@@ -833,20 +834,10 @@ void hw_perf_enable(void)
event = cpuc->event_list[i];
hwc = &event->hw;

- if (hwc->idx == -1) {
+ if (hwc->idx == -1)
x86_assign_hw_event(event, cpuc, i);
- x86_perf_event_set_period(event);
- }
- /*
- * need to mark as active because x86_pmu_disable()
- * clear active_mask and events[] yet it preserves
- * idx
- */
- __set_bit(hwc->idx, cpuc->active_mask);
- cpuc->events[hwc->idx] = event;

- x86_pmu.enable(event);
- perf_event_update_userpage(event);
+ x86_pmu_start(event);
}
cpuc->n_added = 0;
perf_events_lapic_init();
@@ -975,11 +966,17 @@ static int x86_pmu_enable(struct perf_event *event)

static int x86_pmu_start(struct perf_event *event)
{
- if (event->hw.idx == -1)
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int idx = event->hw.idx;
+
+ if (idx == -1)
return -EAGAIN;

x86_perf_event_set_period(event);
+ cpuc->events[idx] = event;
+ __set_bit(idx, cpuc->active_mask);
x86_pmu.enable(event);
+ perf_event_update_userpage(event);

return 0;
}