From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 8456E6B0005 for ; Wed, 6 Jan 2016 22:52:49 -0500 (EST) Received: by mail-pa0-f47.google.com with SMTP id cy9so247663765pac.0 for ; Wed, 06 Jan 2016 19:52:49 -0800 (PST) Received: from mail-pa0-x243.google.com (mail-pa0-x243.google.com. [2607:f8b0:400e:c03::243]) by mx.google.com with ESMTPS id bx1si52514120pab.57.2016.01.06.19.52.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Jan 2016 19:52:48 -0800 (PST) Received: by mail-pa0-x243.google.com with SMTP id pv5so20160483pac.0 for ; Wed, 06 Jan 2016 19:52:48 -0800 (PST) From: Liang Chen Subject: [PATCH V2] mm: mempolicy: skip non-migratable VMAs when setting MPOL_MF_LAZY Date: Thu, 7 Jan 2016 11:52:38 +0800 Message-Id: <1452138758-30031-1-git-send-email-liangchen.linux@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: riel@redhat.com Cc: mgorman@suse.de, akpm@linux-foundation.org, linux-mm@kvack.org, n-horiguchi@ah.jp.nec.com, linux-kernel@vger.kernel.org, Liang Chen , Gavin Guo MPOL_MF_LAZY is not visible from userspace since 'commit a720094ded8c ("mm: mempolicy: Hide MPOL_NOOP and MPOL_MF_LAZY from userspace for now")' , but it should still skip non-migratable VMAs such as VM_IO, VM_PFNMAP, and VM_HUGETLB VMAs, and avoid useless overhead of minor faults. Signed-off-by: Liang Chen Signed-off-by: Gavin Guo --- Changes since v2: - Add more description into the changelog We have been evaluating the enablement of MPOL_MF_LAZY again, and found this issue. And we decided to push this patch upstream no matter if we finally determine to propose re-enablement of MPOL_MF_LAZY or not. Since it can be a potential problem even if MPOL_MF_LAZY is not enabled this time. --- mm/mempolicy.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 87a1779..436ff411 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -610,7 +610,8 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, if (flags & MPOL_MF_LAZY) { /* Similar to task_numa_work, skip inaccessible VMAs */ - if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) + if (vma_migratable(vma) && + vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) change_prot_numa(vma, start, endvma); return 1; } -- 1.9.1 -- 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/ . Don't email: email@kvack.org