Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [resend][PATCH] mm: increase RECLAIM_DISTANCE to 30 | Date | Tue, 12 Oct 2010 13:07:35 +0900 (JST) |
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> On Tue, 12 Oct 2010, KOSAKI Motohiro wrote: > > > > It doesn't determine what the maximum latency to that memory is, it relies > > > on whatever was defined in the SLIT; the only semantics of that distance > > > comes from the ACPI spec that states those distances are relative to the > > > local distance of 10. > > > > Right. but do we need to consider fake SLIT case? I know actually such bogus > > slit are there. but I haven't seen such fake SLIT made serious trouble. > > > > If we can make the assumption that the SLIT entries are truly > representative of the latencies and are adhering to the semantics > presented in the ACPI spec, then this means the VM prefers to do zone > reclaim rather than from other nodes when the latter is 3x more costly. > > That's fine by me, as I've mentioned we've done this for a couple years > because we've had to explicitly disable zone_reclaim_mode for such > configurations. If that's the policy decision that's been made, though, > we _could_ measure the cost at boot and set zone_reclaim_mode depending on > the measured latency rather than relying on the SLIT at all in this case.
ok, got it. thanks.
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