From: Christoph Lameter If a zone is unpopulated then we do not need to check for pages that are to be drained and also not for vm counters that may need to be updated. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton --- mm/page_alloc.c | 5 ++++- mm/vmstat.c | 3 +++ 2 files changed, 7 insertions(+), 1 deletion(-) diff -puN mm/page_alloc.c~do-not-check-unpopulated-zones-for-draining-and-counter mm/page_alloc.c --- a/mm/page_alloc.c~do-not-check-unpopulated-zones-for-draining-and-counter +++ a/mm/page_alloc.c @@ -633,7 +633,7 @@ static int rmqueue_bulk(struct zone *zon #ifdef CONFIG_NUMA /* * Called from the slab reaper to drain pagesets on a particular node that - * belong to the currently executing processor. + * belongs to the currently executing processor. * Note that this function must be called with the thread pinned to * a single processor. */ @@ -647,6 +647,9 @@ void drain_node_pages(int nodeid) struct zone *zone = NODE_DATA(nodeid)->node_zones + z; struct per_cpu_pageset *pset; + if (!populated_zone(zone)) + continue; + pset = zone_pcp(zone, smp_processor_id()); for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) { struct per_cpu_pages *pcp; diff -puN mm/vmstat.c~do-not-check-unpopulated-zones-for-draining-and-counter mm/vmstat.c --- a/mm/vmstat.c~do-not-check-unpopulated-zones-for-draining-and-counter +++ a/mm/vmstat.c @@ -268,6 +268,9 @@ void refresh_cpu_vm_stats(int cpu) for_each_zone(zone) { struct per_cpu_pageset *pcp; + if (!populated_zone(zone)) + continue; + pcp = zone_pcp(zone, cpu); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) _