Messages in this thread | ![/](/images/icornerl.gif) | | From | KOSAKI Motohiro <> | Subject | Re: [PATCH 1/4] vmscan: delegate pageout io to flusher thread if current is kswapd | Date | Thu, 15 Apr 2010 17:26:27 +0900 (JST) |
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Cc to Johannes
> > > > On Apr 14, 2010, at 9:11 PM, KOSAKI Motohiro wrote: > > > > > Now, vmscan pageout() is one of IO throuput degression source. > > > Some IO workload makes very much order-0 allocation and reclaim > > > and pageout's 4K IOs are making annoying lots seeks. > > > > > > At least, kswapd can avoid such pageout() because kswapd don't > > > need to consider OOM-Killer situation. that's no risk. > > > > > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > > > > What's your opinion on trying to cluster the writes done by pageout, > > instead of not doing any paging out in kswapd? > > Something along these lines: > > Interesting. > So, I'd like to review your patch carefully. can you please give me one > day? :)
Hannes, if my remember is correct, you tried similar swap-cluster IO long time ago. now I can't remember why we didn't merged such patch. Do you remember anything?
> > > > > > Cluster writes to disk due to memory pressure. > > > > Write out logically adjacent pages to the one we're paging out > > so that we may get better IOs in these situations: > > These pages are likely to be contiguous on disk to the one we're > > writing out, so they should get merged into a single disk IO. > > > > Signed-off-by: Suleiman Souhlal <suleiman@google.com> > > > >
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