On Wed, 2011-09-07 at 10:37 +0800, Wu Fengguang wrote: > On Tue, Sep 06, 2011 at 10:22:48PM +0800, Peter Zijlstra wrote: > > On Sun, 2011-09-04 at 09:53 +0800, Wu Fengguang wrote: > > > +++ linux-next/mm/page-writeback.c 2011-08-31 14:40:58.000000000 +0800 > > > @@ -1067,6 +1067,9 @@ static void balance_dirty_pages(struct a > > > nr_dirty, bdi_thresh, bdi_dirty, > > > start_time); > > > > > > + if (unlikely(!dirty_exceeded && bdi_async_underrun(bdi))) > > > + break; > > > + > > > dirty_ratelimit = bdi->dirty_ratelimit; > > > pos_ratio = bdi_position_ratio(bdi, dirty_thresh, > > > background_thresh, nr_dirty, > > > > So dirty_exceeded looks like: > > > > > > 1109 dirty_exceeded = (bdi_dirty > bdi_thresh) || > > 1110 (nr_dirty > dirty_thresh); > > > > Would it make sense to write it as: > > > > if (nr_dirty > dirty_thresh || > > (nr_dirty > freerun && bdi_dirty > bdi_thresh)) > > dirty_exceeded = 1; > > > > So that we don't actually throttle bdi thingies when we're still in the > > freerun area? > > Sounds not necessary -- (nr_dirty > freerun) is implicitly true > because there is a big break early in the loop: > > if (nr_dirty > freerun) > break; Ah, totally didn't see that. Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href