Re: [PATCH resend^2] mm: increase RECLAIM_DISTANCE to 30

From: Rob Mueller
Date: Tue Apr 12 2011 - 20:27:04 EST

Recently, Robert Mueller reported zone_reclaim_mode doesn't work
properly on his new NUMA server (Dual Xeon E5520 + Intel S5520UR MB).
He is using Cyrus IMAPd and it's built on a very traditional
single-process model.

Let's add Robert to the cc to see if this is still an issue, it hasn't
been re-reported in over six months.

We definitely still set this in /etc/sysctl.conf on every imap server machine:

vm.zone_reclaim_mode = 0

I believe it still defaults to 1 otherwise. What I haven't tested is if leaving it at 1 still causes problems. It definitely DID previously cause big problems (I think that was around 2.6.34 or so).

I'll try changing it to 1 on a machine for 4 hours, see if it makes a noticeable difference and report back.


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