On Tue, Jun 04, 2013 at 04:31:15PM -0700, Dave Hansen wrote: > On 06/04/2013 04:23 PM, Minchan Kim wrote: > > On Tue, Jun 04, 2013 at 08:24:38AM -0700, Dave Hansen wrote: > >> On 06/03/2013 11:05 PM, Minchan Kim wrote: > >>>>> This ensures that we drain the batch if we are about to perform a > >>>>> pageout() or congestion_wait(), either of which will take some > >>>>> time. We expect this to help mitigate the worst of the latency > >>>>> increase that the batching could cause. > >>> Nice idea but I could see drain before pageout but congestion_wait? > >> > >> That comment managed to bitrot a bit :( > >> > >> The first version of these had the drain before pageout() only. Then, > >> Mel added a congestion_wait() call, and I modified the series to also > >> drain there. But, some other patches took the congestion_wait() back > >> out, so I took that drain back out. > > > > I am looking next-20130530 and it has still a congestion_wait. > > I'm confusing. :( > > > > > > if (PageWriteback(page)) { > > /* Case 1 above */ > > if (current_is_kswapd() && > > PageReclaim(page) && > > zone_is_reclaim_writeback(zone)) { > > congestion_wait(BLK_RW_ASYNC, HZ/10); > > zone_clear_flag(zone, ZONE_WRITEBACK); > >> > >> I _believe_ the only congestion_wait() left in there is a cgroup-related > >> one that we didn't think would cause very much harm. > > > > The congestion_wait I am seeing is not cgroup-related one. > > Yeah, sorry for the confusion. There's been a whole lot of activity in > there. My set is also done on top of a couple of fixes that Mel posted > later on, including this one: > > https://patchwork.kernel.org/patch/2619901/ > > *That* one removes the congestion_wait() you noticed. Thanks for the information. My nitpick just gets disappeared. -- Kind regards, Minchan Kim -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>