On Mon 07-04-14 23:34:26, Mel Gorman wrote: > When it was introduced, zone_reclaim_mode made sense as NUMA distances > punished and workloads were generally partitioned to fit into a NUMA > node. NUMA machines are now common but few of the workloads are NUMA-aware > and it's routine to see major performance due to zone_reclaim_mode being > disabled but relatively few can identify the problem. > > Those that require zone_reclaim_mode are likely to be able to detect when > it needs to be enabled and tune appropriately so lets have a sensible > default for the bulk of users. > > Documentation/sysctl/vm.txt | 17 +++++++++-------- > include/linux/mmzone.h | 1 - > mm/page_alloc.c | 17 +---------------- > 3 files changed, 10 insertions(+), 25 deletions(-) Auto-enabling caused so many reports in the past that it is definitely much better to not be clever and let admins enable zone_reclaim where it is appropriate instead. For both patches. Acked-by: Michal Hocko <mhocko@xxxxxxx> -- Michal Hocko SUSE Labs -- 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>