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Message-Id: <1367291838-5490-5-git-send-email-kosaki.motohiro@gmail.com>
Date: Mon, 29 Apr 2013 23:17:12 -0400
From: kosaki.motohiro@...il.com
To: linux-kernel@...r.kernel.org
Cc: Olivier Langlois <olivier@...llion01.com>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Steven Rostedt <rostedt@...dmis.org>,
David Miller <davem@...emloft.net>,
Thomas Gleixner <tglx@...utronix.de>,
Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Subject: [PATCH 04/10] posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting
From: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
When tsk->signal->cputimer->running is 1, signal->cputimer and
tsk->sum_sched_runtime increase the same pace. update_curr() increase
both account.
However, there is one exeception. When thread exiting, __exit_signal()
turns over task's sum_shced_runtime to sig->sum_sched_runtime. but it
doesn't stop signal->cputimer accounting.
This inconsistency makes too early POSIX timer wakeup. Fix it.
Signed-off-by: Olivier Langlois <olivier@...llion01.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
---
kernel/sched/stats.h | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 2ef90a5..5a0cfc4 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -225,6 +225,13 @@ static inline void account_group_exec_runtime(struct task_struct *tsk,
if (!cputimer->running)
return;
+ /*
+ * After turning over se.sum_exec_runtime to sig->sum_sched_runtime
+ * in __exit_signal(), we must not account exec_runtime for consistency.
+ */
+ if (unlikely(!tsk->sighand))
+ return;
+
raw_spin_lock(&cputimer->lock);
cputimer->cputime.sum_exec_runtime += ns;
raw_spin_unlock(&cputimer->lock);
--
1.7.1
--
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