This is a note to let you know that I've just added the patch titled
perf: Fix interrupt handler timing harness
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-fix-interrupt-handler-timing-harness.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e5302920da9ef23f9d19d4e9ac85704cc25bee7a Mon Sep 17 00:00:00 2001
From: Stephane Eranian <eranian@xxxxxxxxxx>
Date: Fri, 5 Jul 2013 00:30:11 +0200
Subject: perf: Fix interrupt handler timing harness
From: Stephane Eranian <eranian@xxxxxxxxxx>
commit e5302920da9ef23f9d19d4e9ac85704cc25bee7a upstream.
This patch fixes a serious bug in:
14c63f17b1fd perf: Drop sample rate when sampling is too slow
There was an misunderstanding on the API of the do_div()
macro. It returns the remainder of the division and this
was not what the function expected leading to disabling the
interrupt latency watchdog.
This patch also remove a duplicate assignment in
perf_sample_event_took().
Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: dave.hansen@xxxxxxxxxxxxxxx
Cc: ak@xxxxxxxxxxxxxxx
Cc: jolsa@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Weng Meiling <wengmeiling.weng@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -182,7 +182,7 @@ void update_perf_cpu_limits(void)
u64 tmp = perf_sample_period_ns;
tmp *= sysctl_perf_cpu_time_max_percent;
- tmp = do_div(tmp, 100);
+ do_div(tmp, 100);
atomic_set(&perf_sample_allowed_ns, tmp);
}
@@ -230,7 +230,7 @@ DEFINE_PER_CPU(u64, running_sample_lengt
void perf_sample_event_took(u64 sample_len_ns)
{
u64 avg_local_sample_len;
- u64 local_samples_len = __get_cpu_var(running_sample_length);
+ u64 local_samples_len;
if (atomic_read(&perf_sample_allowed_ns) == 0)
return;
Patches currently in stable-queue which might be from eranian@xxxxxxxxxx are
queue-3.10/perf-fix-interrupt-handler-timing-harness.patch
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