From 9d3c3354bb85bab4d865fe95039443f09a4c8394 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 22 Mar 2018 16:17:45 -0700 Subject: mm, thp: do not cause memcg oom for thp Commit 2516035499b9 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations") changed the page allocator to no longer detect thp allocations based on __GFP_NORETRY. It did not, however, modify the mem cgroup try_charge() path to avoid oom kill for either khugepaged collapsing or thp faulting. It is never expected to oom kill a process to allocate a hugepage for thp; reclaim is governed by the thp defrag mode and MADV_HUGEPAGE, but allocations (and charging) should fallback instead of oom killing processes. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803191409420.124411@chino.kir.corp.google.com Fixes: 2516035499b9 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations") Signed-off-by: David Rientjes Cc: "Kirill A. Shutemov" Cc: Michal Hocko Cc: Vlastimil Babka Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/khugepaged.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'mm/khugepaged.c') diff --git a/mm/khugepaged.c b/mm/khugepaged.c index c15da1ea7e63..e42568284e06 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -965,7 +965,9 @@ static void collapse_huge_page(struct mm_struct *mm, goto out_nolock; } - if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) { + /* Do not oom kill for khugepaged charges */ + if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp | __GFP_NORETRY, + &memcg, true))) { result = SCAN_CGROUP_CHARGE_FAIL; goto out_nolock; } @@ -1324,7 +1326,9 @@ static void collapse_shmem(struct mm_struct *mm, goto out; } - if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) { + /* Do not oom kill for khugepaged charges */ + if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp | __GFP_NORETRY, + &memcg, true))) { result = SCAN_CGROUP_CHARGE_FAIL; goto out; } -- cgit v1.2.3-55-g7522