Messages in this thread | | | Date | Tue, 8 Apr 2014 09:14:43 +0200 | From | Andres Freund <> | Subject | Re: [PATCH 1/2] mm: Disable zone_reclaim_mode by default |
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Hi,
On 2014-04-07 23:34:27 +0100, Mel Gorman wrote: > zone_reclaim_mode causes processes to prefer reclaiming memory from local > node instead of spilling over to other nodes. This made sense initially when > NUMA machines were almost exclusively HPC and the workload was partitioned > into nodes. The NUMA penalties were sufficiently high to justify reclaiming > the memory. On current machines and workloads it is often the case that > zone_reclaim_mode destroys performance but not all users know how to detect > this. Favour the common case and disable it by default. Users that are > sophisticated enough to know they need zone_reclaim_mode will detect it.
Unsurprisingly I am in favor of this.
> Documentation/sysctl/vm.txt | 17 +++++++++-------- > mm/page_alloc.c | 2 -- > 2 files changed, 9 insertions(+), 10 deletions(-)
But I think linux/topology.h's comment about RECLAIM_DISTANCE should be adapted as well.
Thanks,
Andres
-- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
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