From fa41b900c30b45fab03783724932dc30cd46a6be Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 22 Mar 2018 16:17:31 -0700 Subject: mm/thp: do not wait for lock_page() in deferred_split_scan() deferred_split_scan() gets called from reclaim path. Waiting for page lock may lead to deadlock there. Replace lock_page() with trylock_page() and skip the page if we failed to lock it. We will get to the page on the next scan. Link: http://lkml.kernel.org/r/20180315150747.31945-1-kirill.shutemov@linux.intel.com Fixes: 9a982250f773 ("thp: introduce deferred_split_huge_page()") Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 87ab9b8f56b5..529cf36b7edb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2783,11 +2783,13 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, list_for_each_safe(pos, next, &list) { page = list_entry((void *)pos, struct page, mapping); - lock_page(page); + if (!trylock_page(page)) + goto next; /* split_huge_page() removes page from list on success */ if (!split_huge_page(page)) split++; unlock_page(page); +next: put_page(page); } -- cgit v1.2.1 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/huge_memory.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'mm/huge_memory.c') 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) -- cgit v1.2.1