On Mon, 2015-03-02 at 20:40 +0100, Oleg Nesterov wrote: > Well, I forgot everything about this code, but let me ask anyway ;) > > On 03/02, Jason Low wrote:
> > @@ -222,13 +239,10 @@ void thread_group_cputimer(struct task_struct *tsk, > > struct task_cputime *times) > > * it. > > */ > > thread_group_cputime(tsk, &sum); > > - raw_spin_lock_irqsave(&cputimer->lock, flags); > > - cputimer->running = 1; > > - update_gt_cputime(&cputimer->cputime, &sum); > > - } else > > - raw_spin_lock_irqsave(&cputimer->lock, flags); > > - *times = cputimer->cputime; > > - raw_spin_unlock_irqrestore(&cputimer->lock, flags); > > + update_gt_cputime(cputimer, &sum); > > + ACCESS_ONCE(cputimer->running) = 1; > > WRITE_ONCE() looks better... Okay, I can update that. > but it is not clear to me why do we need it > at all. Peter suggested it here as we would now be updating the running field without the lock: https://lkml.org/lkml/2015/1/23/641 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
