From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752780AbbCGUNa (ORCPT ); Sat, 7 Mar 2015 15:13:30 -0500 Received: from mail-ie0-f171.google.com ([209.85.223.171]:34588 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752592AbbCGUN1 (ORCPT ); Sat, 7 Mar 2015 15:13:27 -0500 MIME-Version: 1.0 In-Reply-To: <1425741651-29152-2-git-send-email-mgorman@suse.de> References: <1425741651-29152-1-git-send-email-mgorman@suse.de> <1425741651-29152-2-git-send-email-mgorman@suse.de> Date: Sat, 7 Mar 2015 12:13:27 -0800 X-Google-Sender-Auth: UxM394jCDzp0IGnwrumZnD6349Y Message-ID: Subject: Re: [PATCH 1/4] mm: thp: Return the correct value for change_huge_pmd From: Linus Torvalds To: Mel Gorman Cc: Dave Chinner , Andrew Morton , Ingo Molnar , Aneesh Kumar , Linux Kernel Mailing List , Linux-MM , xfs@oss.sgi.com, ppc-dev Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Looks obviously correct. The old code was just very wrong. Acked-by: Linus Torvalds Linus On Sat, Mar 7, 2015 at 7:20 AM, Mel Gorman wrote: > The wrong value is being returned by change_huge_pmd since commit > 10c1045f28e8 ("mm: numa: avoid unnecessary TLB flushes when setting > NUMA hinting entries") which allows a fallthrough that tries to adjust > non-existent PTEs. This patch corrects it. > > Signed-off-by: Mel Gorman > --- > mm/huge_memory.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index fc00c8cb5a82..194c0f019774 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1482,6 +1482,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, > > if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { > pmd_t entry; > + ret = 1; > > /* > * Avoid trapping faults against the zero page. The read-only > @@ -1490,11 +1491,10 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, > */ > if (prot_numa && is_huge_zero_pmd(*pmd)) { > spin_unlock(ptl); > - return 0; > + return ret; > } > > if (!prot_numa || !pmd_protnone(*pmd)) { > - ret = 1; > entry = pmdp_get_and_clear_notify(mm, addr, pmd); > entry = pmd_modify(entry, newprot); > ret = HPAGE_PMD_NR; > -- > 2.1.2 >