From: David Rientjes Date: Thu, 12 Apr 2012 22:51:58 +0000 (+1000) Subject: mm, thp: allow fallback when pte_alloc_one() fails for huge pmd X-Git-Tag: next-20120417~2^2~88 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0996d3431e003056087c4a81998fdfa80f7aaa29;p=karo-tx-linux.git mm, thp: allow fallback when pte_alloc_one() fails for huge pmd The transparent hugepages feature is careful to not invoke the oom killer when a hugepage cannot be allocated. pte_alloc_one() failing in __do_huge_pmd_anonymous_page(), however, currently results in VM_FAULT_OOM which invokes the pagefault oom killer to kill a memory-hogging task. This is unnecessary since it's possible to drop the reference to the hugepage and fallback to allocating a small page. Signed-off-by: David Rientjes Cc: Andrea Arcangeli Signed-off-by: Andrew Morton --- diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8ab2d24faae5..d7d7165156ca 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -640,11 +640,8 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, VM_BUG_ON(!PageCompound(page)); pgtable = pte_alloc_one(mm, haddr); - if (unlikely(!pgtable)) { - mem_cgroup_uncharge_page(page); - put_page(page); + if (unlikely(!pgtable)) return VM_FAULT_OOM; - } clear_huge_page(page, haddr, HPAGE_PMD_NR); __SetPageUptodate(page); @@ -723,8 +720,14 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, put_page(page); goto out; } + if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, + page))) { + mem_cgroup_uncharge_page(page); + put_page(page); + goto out; + } - return __do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page); + return 0; } out: /*