Messages in this thread | | | Date | Wed, 31 Aug 2011 09:11:02 +0200 | From | Stefan Priebe - Profihost AG <> | Subject | Re: slow performance on disk/network i/o full speed after drop_caches |
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Hi Fengguang, Hi Yanhai,
> you're abssolutely corect zone_reclaim_mode is on - but why? > There must be some linux software which switches it on. > > ~# grep 'zone_reclaim_mode' /etc/sysctl.* -r -i > ~# > > also > ~# grep 'zone_reclaim_mode' /etc/sysctl.* -r -i > ~# > > tells us nothing. > > I've then read this: > > "zone_reclaim_mode is set during bootup to 1 if it is determined that > pages from remote zones will cause a measurable performance reduction. > The page allocator will then reclaim easily reusable pages (those page > cache pages that are currently not used) before allocating off node pages." > > Why does the kernel do that here in our case on these machines.
Can nobody help why the kernel in this case set it to 1?
Stefan
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