[tip:perf/core] perf_event: Initialize data.period in perf_swevent_hrtimer()

[tip-bot for Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>]

Commit-ID:  59d069eb5ae9b033ed1c124c92e1532c4a958991
Gitweb:     http://git.kernel.org/tip/59d069eb5ae9b033ed1c124c92e1532c4a958991
Author:     Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
AuthorDate: Tue, 1 Dec 2009 17:30:08 +0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 1 Dec 2009 11:19:07 +0100

perf_event: Initialize data.period in perf_swevent_hrtimer()

In current code in perf_swevent_hrtimer(), data.period is not
initialized, The result is obvious wrong:

 # ./perf record -f -e cpu-clock make
 # ./perf report
 # Samples: 1740
 #
 # Overhead   Command                                   ......
 # ........  ........  ..........................................
 #
   1025422183050275328.00%        sh  libc-2.9.90.so ...
   1025422183050275328.00%      perl  libperl.so     ...
   1025422168240043264.00%      perl  [kernel]       ...
   1025422030011210752.00%      perl  [kernel]       ...

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org>
LKML-Reference: <4B14E220.2050107@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/perf_event.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 0b9ca2d..040ee51 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4010,6 +4010,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 	event->pmu->read(event);
 
 	data.addr = 0;
+	data.period = event->hw.last_period;
 	regs = get_irq_regs();
 	/*
 	 * In case we exclude kernel IPs or are somehow not in interrupt