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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>