Messages in this thread | | | Date | Wed, 5 Jun 2013 08:23:15 +0900 | From | Minchan Kim <> | Subject | Re: [v5][PATCH 6/6] mm: vmscan: drain batch list during long operations |
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Hello Dave,
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.
I'd like to clear this confusing. Thanks.
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-- Kind regards, Minchan Kim
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