From: KOSAKI Motohiro <[email protected]> When tsk->signal->cputimer->running is 1, signal->cputimer and tsk->sum_sched_runtime increase at the same pace because update_curr() increases both accounting.
However, there is one exception. 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 POSIX timer wake up too early. This patch fixes it. Cc: Thomas Gleixner <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Ingo Molnar <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Signed-off-by: Olivier Langlois <[email protected]> Signed-off-by: KOSAKI Motohiro <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
