On 17.12.2013 22:23, Mel Gorman wrote:
On Tue, Dec 17, 2013 at 04:07:35PM +0100, Zlatko Calusic wrote:
On 13.12.2013 15:10, Mel Gorman wrote:
Kicked this another bit today. It's still a bit half-baked but it restores
the historical performance and leaves the door open at the end for playing
nice with distributing file pages between nodes. Finishing this series
depends on whether we are going to make the remote node behaviour of the
fair zone allocation policy configurable or redefine MPOL_LOCAL. I'm in
favour of the configurable option because the default can be redefined and
tested while giving users a "compat" mode if we discover the new default
behaviour sucks for some workload.
I'll start a 5-day test of this patchset in a few hours, unless you
can send an updated one in the meantime. I intend to test it on a
rather boring 4GB x86_64 machine that before Johannes' work had lots
of trouble balancing zones. Would you recommend to use the default
settings, i.e. don't mess with tunables at this point?
For me at least I would prefer you tested v3 of the series with the
default settings of not interleaving file-backed pages on remote nodes
by default. Johannes might request testing with that knob enabled if the
machine is NUMA although I doubt it is with 4G of RAM.
Tested v3 on UMA machine, with default setting. I see no regression, no
issues whatsoever. From what I understand, this whole series is about
fixing issues noticed on NUMA, so I wish you good luck with that (no
such hardware here). Just be extra careful not to disturb finally very
well balanced MM on more common machines (and especially those equipped
with 4GB RAM). And once again thank you Johannes for your work, you did
a great job.
Tested-by: Zlatko Calusic <zcalusic@xxxxxxxxxxx>
--
Zlatko
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