linux-kernel - [PATCH perf/core/urgent] perf, x86: Handle in flight IRQs on P4 platform

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Date:	Wed, 29 Sep 2010 23:01:38 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	mingo@...e.hu
Cc:	linux-kernel@...r.kernel.org, fweisbec@...il.com,
	peterz@...radead.org, Cyrill Gorcunov <gorcunov@...il.com>,
	Cyrill Gorcunov <gorcunov@...nvz.org>,
	Robert Richter <robert.richter@....com>,
	Lin Ming <ming.m.lin@...el.com>,
	Don Zickus <dzickus@...hat.com>
Subject: [PATCH perf/core/urgent] perf, x86: Handle in flight IRQs on P4 platform

From: Cyrill Gorcunov <gorcunov@...il.com>

Stephane reported we've forgot to guard the P4 platform
against spurious in-flight performance IRQs. Fix it.

[ the patch is a complement to commit 63e6be6d98e1 ]

Reported-by: Stephane Eranian <eranian@...gle.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@...nvz.org>
CC: Robert Richter <robert.richter@....com>
CC: Lin Ming <ming.m.lin@...el.com>
Signed-off-by: Don Zickus <dzickus@...hat.com>
---
 arch/x86/kernel/cpu/perf_event_p4.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index b560db3..2490151 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -660,8 +660,12 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
 	for (idx = 0; idx < x86_pmu.num_counters; idx++) {
 		int overflow;
 
-		if (!test_bit(idx, cpuc->active_mask))
+		if (!test_bit(idx, cpuc->active_mask)) {
+			/* catch in-flight IRQs */
+			if (__test_and_clear_bit(idx, cpuc->running))
+				handled++;
 			continue;
+		}
 
 		event = cpuc->events[idx];
 		hwc = &event->hw;
-- 
1.7.2.3

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