From 494de90098784b8e2797598cefdd34188884ec2e Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 3 Jul 2008 05:27:51 +0100 Subject: [PATCH] Do not overwrite nr_zones on !NUMA when initialising zlcache_ptr The non-NUMA case of build_zonelist_cache() would initialize the zlcache_ptr for both node_zonelists[] to NULL. Which is problematic, since non-NUMA only has a single node_zonelists[] entry, and trying to zero the non-existent second one just overwrote the nr_zones field instead. As kswapd uses this value to determine what reclaim work is necessary, the result is that kswapd never reclaims. This causes processes to stall frequently in low-memory situations as they always direct reclaim. This patch initialises zlcache_ptr correctly. Signed-off-by: Mel Gorman Tested-by: Dan Williams [ Simplified patch a bit ] Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2f552955a02..f32fae3121f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2328,7 +2328,6 @@ static void build_zonelists(pg_data_t *pgdat) static void build_zonelist_cache(pg_data_t *pgdat) { pgdat->node_zonelists[0].zlcache_ptr = NULL; - pgdat->node_zonelists[1].zlcache_ptr = NULL; } #endif /* CONFIG_NUMA */ -- 2.20.1