Re: [v5][PATCH 6/6] mm: vmscan: drain batch list during long operations

Dave Hansen
2013-06-04T15:24:41Z

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 _believe_ the only congestion_wait() left in there is a cgroup-related
one that we didn't think would cause very much harm.