From d51d885bbb137cc8e1704e76be1846c5e0d5e8b4 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Wed, 6 Aug 2014 16:05:49 -0700 Subject: [PATCH] mm: huge_memory: use GFP_TRANSHUGE when charging huge pages Transparent huge page charges prefer falling back to regular pages rather than spending a lot of time in direct reclaim. Desired reclaim behavior is usually declared in the gfp mask, but THP charges use GFP_KERNEL and then rely on the fact that OOM is disabled for THP charges, and that OOM-disabled charges don't retry reclaim. Needless to say, this is anything but obvious and quite error prone. Convert THP charges to use GFP_TRANSHUGE instead, which implies __GFP_NORETRY, to indicate the low-latency requirement. Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Cc: Hugh Dickins Cc: Tejun Heo Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4b95ff4120f5..24e354c2b59e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -827,7 +827,7 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, count_vm_event(THP_FAULT_FALLBACK); return VM_FAULT_FALLBACK; } - if (unlikely(mem_cgroup_charge_anon(page, mm, GFP_KERNEL))) { + if (unlikely(mem_cgroup_charge_anon(page, mm, GFP_TRANSHUGE))) { put_page(page); count_vm_event(THP_FAULT_FALLBACK); return VM_FAULT_FALLBACK; @@ -1132,7 +1132,7 @@ alloc: goto out; } - if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL))) { + if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_TRANSHUGE))) { put_page(new_page); if (page) { split_huge_page(page); @@ -2399,7 +2399,7 @@ static void collapse_huge_page(struct mm_struct *mm, if (!new_page) return; - if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL))) + if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_TRANSHUGE))) return; /* -- 2.20.1