Messages in this thread | | | Date | Thu, 15 Jul 2004 02:04:38 +0200 | From | Andrea Arcangeli <> | Subject | Re: VM Problems in 2.6.7 (Too active OOM Killer) |
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On Wed, Jul 14, 2004 at 04:47:04PM -0700, Peter Zaitsev wrote: > To be honest I do not really understand this OOM without swap problem at > all, why is it possible to move pages from ZONE_NORMAL to swap but not > to other zones ?
the oom without swap you reproduced is not related to ZONE_NORMAL shortage. The pages in ZONE_NORMAL never goes into swap.
the ZONE_NORMAL oom is a separate issue from the oom killing you reproduced. with 2.6.7 if you were hitting the ZONE_NORMAL shortage your machine would lockup and it would never oom-kill anything (Andrew just changed that in kernel CVS, so thanks to that change a ZONE_NORMAL shortage will not deadlock anymore in 2.6.8, but OTOH in 2.6.8 adding swap will not be enough anymore to workaround the oom-killing you reproduced).
About the ZONE_NORMAL shortage without swap, rather than running cpu-cache-hungry memcopies from lowmemzone to highmem (or even worse to pass through swap like it happens in 2.6 mainline with swap enabled), I believe it's better to reserve some ram in the lowmem zone, 800M of ram on a 32G box should be a cheap price to pay compared to the cpu/IO cost involved in moving memory around during the bench. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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