linux-kernel - [tip:perf/core] perf_event: x86: Deduplicate the disable code

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Message-ID: <tip-2e8418736dff9c6fdadb2f87dcc2087cebf32167@git.kernel.org>
Date:	Fri, 29 Jan 2010 09:29:37 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, eranian@...gle.com, hpa@...or.com,
	mingo@...hat.com, a.p.zijlstra@...llo.nl, tglx@...utronix.de,
	mingo@...e.hu
Subject: [tip:perf/core] perf_event: x86: Deduplicate the disable code

Commit-ID:  2e8418736dff9c6fdadb2f87dcc2087cebf32167
Gitweb:     http://git.kernel.org/tip/2e8418736dff9c6fdadb2f87dcc2087cebf32167
Author:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Mon, 25 Jan 2010 15:58:43 +0100
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 29 Jan 2010 09:01:45 +0100

perf_event: x86: Deduplicate the disable code

Share the meat of the x86_pmu_disable() code with hw_perf_enable().

Also remove the barrier() from that code, since I could not convince
myself we actually need it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Stephane Eranian <eranian@...gle.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/kernel/cpu/perf_event.c |   29 +++++++++++++----------------
 1 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index fdbe248..07fa0c2 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1401,6 +1401,8 @@ static inline void x86_assign_hw_event(struct perf_event *event,
 	}
 }
 
+static void __x86_pmu_disable(struct perf_event *event, struct cpu_hw_events *cpuc);
+
 void hw_perf_enable(void)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -1426,13 +1428,7 @@ void hw_perf_enable(void)
 			if (hwc->idx == -1 || hwc->idx == cpuc->assign[i])
 				continue;
 
-			x86_pmu.disable(hwc, hwc->idx);
-
-			clear_bit(hwc->idx, cpuc->active_mask);
-			barrier();
-			cpuc->events[hwc->idx] = NULL;
-
-			x86_perf_event_update(event, hwc, hwc->idx);
+			__x86_pmu_disable(event, cpuc);
 
 			hwc->idx = -1;
 		}
@@ -1822,11 +1818,10 @@ static void intel_pmu_drain_bts_buffer(struct cpu_hw_events *cpuc)
 	event->pending_kill = POLL_IN;
 }
 
-static void x86_pmu_disable(struct perf_event *event)
+static void __x86_pmu_disable(struct perf_event *event, struct cpu_hw_events *cpuc)
 {
-	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 	struct hw_perf_event *hwc = &event->hw;
-	int i, idx = hwc->idx;
+	int idx = hwc->idx;
 
 	/*
 	 * Must be done before we disable, otherwise the nmi handler
@@ -1836,12 +1831,6 @@ static void x86_pmu_disable(struct perf_event *event)
 	x86_pmu.disable(hwc, idx);
 
 	/*
-	 * Make sure the cleared pointer becomes visible before we
-	 * (potentially) free the event:
-	 */
-	barrier();
-
-	/*
 	 * Drain the remaining delta count out of a event
 	 * that we are disabling:
 	 */
@@ -1852,6 +1841,14 @@ static void x86_pmu_disable(struct perf_event *event)
 		intel_pmu_drain_bts_buffer(cpuc);
 
 	cpuc->events[idx] = NULL;
+}
+
+static void x86_pmu_disable(struct perf_event *event)
+{
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+	int i;
+
+	__x86_pmu_disable(event, cpuc);
 
 	for (i = 0; i < cpuc->n_events; i++) {
 		if (event == cpuc->event_list[i]) {
--
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