linux-kernel - [tip:perf/urgent] perf, x86: Use unlocked bitops

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Date:	Wed, 10 Mar 2010 13:11:47 GMT
From:	tip-bot for 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,
	acme@...radead.org, a.p.zijlstra@...llo.nl, tglx@...utronix.de,
	mingo@...e.hu
Subject: [tip:perf/urgent] perf, x86: Use unlocked bitops

Commit-ID:  34538ee77b39a12702e0f4c3ed9e8fa2dd5eb92c
Gitweb:     http://git.kernel.org/tip/34538ee77b39a12702e0f4c3ed9e8fa2dd5eb92c
Author:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Tue, 2 Mar 2010 21:16:55 +0100
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Wed, 10 Mar 2010 13:22:29 +0100

perf, x86: Use unlocked bitops

There is no concurrency on these variables, so don't use LOCK'ed ops.

As to the intel_pmu_handle_irq() status bit clean, nobody uses that so
remove it all together.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: paulus@...ba.org
Cc: eranian@...gle.com
Cc: robert.richter@....com
Cc: fweisbec@...il.com
Cc: Arnaldo Carvalho de Melo <acme@...radead.org>
LKML-Reference: <20100304140100.240023029@...llo.nl>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/kernel/cpu/perf_event.c       |    8 ++++----
 arch/x86/kernel/cpu/perf_event_amd.c   |    2 +-
 arch/x86/kernel/cpu/perf_event_intel.c |    1 -
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 2dd704f..01b1667 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -643,7 +643,7 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
 		if (test_bit(hwc->idx, used_mask))
 			break;
 
-		set_bit(hwc->idx, used_mask);
+		__set_bit(hwc->idx, used_mask);
 		if (assign)
 			assign[i] = hwc->idx;
 	}
@@ -692,7 +692,7 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
 			if (j == X86_PMC_IDX_MAX)
 				break;
 
-			set_bit(j, used_mask);
+			__set_bit(j, used_mask);
 
 			if (assign)
 				assign[i] = j;
@@ -842,7 +842,7 @@ void hw_perf_enable(void)
 			 * clear active_mask and events[] yet it preserves
 			 * idx
 			 */
-			set_bit(hwc->idx, cpuc->active_mask);
+			__set_bit(hwc->idx, cpuc->active_mask);
 			cpuc->events[hwc->idx] = event;
 
 			x86_pmu.enable(event);
@@ -1057,7 +1057,7 @@ static void x86_pmu_stop(struct perf_event *event)
 	 * Must be done before we disable, otherwise the nmi handler
 	 * could reenable again:
 	 */
-	clear_bit(idx, cpuc->active_mask);
+	__clear_bit(idx, cpuc->active_mask);
 	x86_pmu.disable(event);
 
 	/*
diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c
index 014528b..573458f 100644
--- a/arch/x86/kernel/cpu/perf_event_amd.c
+++ b/arch/x86/kernel/cpu/perf_event_amd.c
@@ -287,7 +287,7 @@ static struct amd_nb *amd_alloc_nb(int cpu, int nb_id)
 	 * initialize all possible NB constraints
 	 */
 	for (i = 0; i < x86_pmu.num_events; i++) {
-		set_bit(i, nb->event_constraints[i].idxmsk);
+		__set_bit(i, nb->event_constraints[i].idxmsk);
 		nb->event_constraints[i].weight = 1;
 	}
 	return nb;
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index a840948..d87421c 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -765,7 +765,6 @@ again:
 	for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
 		struct perf_event *event = cpuc->events[bit];
 
-		clear_bit(bit, (unsigned long *) &status);
 		if (!test_bit(bit, cpuc->active_mask))
 			continue;
 
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