linux-kernel - [tip:perfcounters/core] perf_counter: fix hrtimer sampling

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Date:	Fri, 13 Mar 2009 16:09:43 GMT
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	a.p.zijlstra@...llo.nl, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:perfcounters/core] perf_counter: fix hrtimer sampling

Commit-ID:  a27cdc586523eec54717c8c56ff079b3869770d2
Gitweb:     http://git.kernel.org/tip/a27cdc586523eec54717c8c56ff079b3869770d2
Author:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Fri, 13 Mar 2009 16:43:47 +0100
Commit:     Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 13 Mar 2009 16:59:00 +0100

perf_counter: fix hrtimer sampling

Impact: fix deadlock with perfstat

Fix for the perfstat fubar..

We cannot unconditionally call hrtimer_cancel() without ever having done
hrtimer_init() on the thing.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
LKML-Reference: <1236959027.22447.149.camel@...ns>
Signed-off-by: Ingo Molnar <mingo@...e.hu>


---
 kernel/perf_counter.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 8d6ecfa..d6cc222 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1571,9 +1571,9 @@ static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
 	int cpu = raw_smp_processor_id();
 
 	atomic64_set(&hwc->prev_count, cpu_clock(cpu));
+	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hwc->hrtimer.function = perf_swcounter_hrtimer;
 	if (hwc->irq_period) {
-		hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-		hwc->hrtimer.function = perf_swcounter_hrtimer;
 		__hrtimer_start_range_ns(&hwc->hrtimer,
 				ns_to_ktime(hwc->irq_period), 0,
 				HRTIMER_MODE_REL, 0);
@@ -1635,9 +1635,9 @@ static int task_clock_perf_counter_enable(struct perf_counter *counter)
 	struct hw_perf_counter *hwc = &counter->hw;
 
 	atomic64_set(&hwc->prev_count, task_clock_perf_counter_val(counter, 0));
+	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hwc->hrtimer.function = perf_swcounter_hrtimer;
 	if (hwc->irq_period) {
-		hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-		hwc->hrtimer.function = perf_swcounter_hrtimer;
 		__hrtimer_start_range_ns(&hwc->hrtimer,
 				ns_to_ktime(hwc->irq_period), 0,
 				HRTIMER_MODE_REL, 0);
--
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