2016-06-09 3:05 GMT+08:00 Rik van Riel <[email protected]>: > On Wed, 2016-06-08 at 11:05 +0800, Wanpeng Li wrote: >> >> @@ -681,12 +681,17 @@ static cputime_t vtime_delta(struct task_struct >> *tsk) >> static cputime_t get_vtime_delta(struct task_struct *tsk) >> { >> unsigned long now = READ_ONCE(jiffies); >> - unsigned long delta = now - tsk->vtime_snap; >> + cputime_t delta_time, steal_time; >> >> + steal_time = >> jiffies_to_cputime(steal_account_process_tick()); >> + delta_time = jiffies_to_cputime(now - tsk->vtime_snap); >> WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE); >> tsk->vtime_snap = now; >> >> - return jiffies_to_cputime(delta); >> + if (steal_time < delta_time) >> + delta_time -= steal_time; >> + >> + return delta_time; >> } > > This isn't right. > > If steal_time is equal to or larger than delta_time, > get_vtime_delta needs to return 0, not delta_time. > > Otherwise the same time will be counted twice.
Paolo also pointed out this yesterday, so his proposal looks good to you, right? Regards, Wanpeng Li
