From 1eb41bb07e568629805acb8455c44b6709819551 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Mon, 23 Sep 2019 15:37:16 -0700 Subject: [PATCH] mm, oom: consider present pages for the node size constrained_alloc() calculates the size of the oom domain by using node_spanned_pages which is incorrect because this is the full range of the physical memory range that the numa node occupies rather than the memory that backs that range which is represented by node_present_pages. Sparsely populated nodes (e.g. after memory hot remove or simply sparse due to memory layout) can have really a large difference between the two. This shouldn't really cause any real user observable problems because the oom calculates a ratio against totalpages and used memory cannot exceed present pages but it is confusing and wrong from code point of view. Link: http://lkml.kernel.org/r/20190829163443.899-1-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: David Hildenbrand Reviewed-by: David Hildenbrand Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/oom_kill.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1530fcc..c1d9496 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -287,7 +287,7 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc) !nodes_subset(node_states[N_MEMORY], *oc->nodemask)) { oc->totalpages = total_swap_pages; for_each_node_mask(nid, *oc->nodemask) - oc->totalpages += node_spanned_pages(nid); + oc->totalpages += node_present_pages(nid); return CONSTRAINT_MEMORY_POLICY; } @@ -300,7 +300,7 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc) if (cpuset_limited) { oc->totalpages = total_swap_pages; for_each_node_mask(nid, cpuset_current_mems_allowed) - oc->totalpages += node_spanned_pages(nid); + oc->totalpages += node_present_pages(nid); return CONSTRAINT_CPUSET; } return CONSTRAINT_NONE; -- 2.7.4