Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 4 Aug 2004 17:02:05 -0700 (PDT) | From | Shantanu Goel <> | Subject | Re: [VM PATCH 2.6.8-rc1] Prevent excessive scanning of lower zone |
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Hi Andrew,
--- Andrew Morton <akpm@osdl.org> wrote:
> Shantanu Goel <sgoel01@yahoo.com> wrote: > > > > I emailed this a few weeks back to the list but it > > seems to have gotten lost... > > It came through. I was unable to reproduce the > disproportional scanning > rate on almost exactly the same setup, so I parked > the problem for a while. > > I do agree with the analysis though. The problem > _could_ occur. I dunno > why it happens for you and not for me... >
Actually, the analysis turned out to be not entirely correct. I think I have identified the offending code. Please see attached patch. It makes kswapd() skip zones which contain greater than "pages_high" pages.
Machine setup is the same as before. 2x2.0Ghz Xeon w/HT, memory 256M (manually pegged). I see this lopsided lower zone scanning on a dual Opteron machine as well.
Attached are the kernbench results for stock 2.6.8-rc1 and 2.6.8-rc1 with patch.
Thanks, Shantanu
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