From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx188.postini.com [74.125.245.188]) by kanga.kvack.org (Postfix) with SMTP id B288E6B004A for ; Mon, 2 Apr 2012 21:30:25 -0400 (EDT) Received: by mail-iy0-f169.google.com with SMTP id r24so6557991iaj.14 for ; Mon, 02 Apr 2012 18:30:25 -0700 (PDT) Date: Mon, 2 Apr 2012 18:30:23 -0700 (PDT) From: David Rientjes Subject: [patch 2/2] mm, thp: allow fallback when pte_alloc_one() fails for huge pmd In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Andrea Arcangeli , linux-mm@kvack.org 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 --- mm/huge_memory.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c --- 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: /* -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org