From 9d3c3354bb85bab4d865fe95039443f09a4c8394 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 22 Mar 2018 16:17:45 -0700 Subject: [PATCH] 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/huge_memory.c | 5 +++-- mm/khugepaged.c | 8 ++++++-- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 529cf36b7edb..5a68730eebd6 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -555,7 +555,8 @@ static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, VM_BUG_ON_PAGE(!PageCompound(page), page); - if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) { + if (mem_cgroup_try_charge(page, vma->vm_mm, gfp | __GFP_NORETRY, &memcg, + true)) { put_page(page); count_vm_event(THP_FAULT_FALLBACK); return VM_FAULT_FALLBACK; @@ -1316,7 +1317,7 @@ alloc: } if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, - huge_gfp, &memcg, true))) { + huge_gfp | __GFP_NORETRY, &memcg, true))) { put_page(new_page); split_huge_pmd(vma, vmf->pmd, vmf->address); if (page) 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; } -- 2.20.1