From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yk0-f170.google.com (mail-yk0-f170.google.com [209.85.160.170]) by kanga.kvack.org (Postfix) with ESMTP id C30FE6B0009 for ; Mon, 18 Jan 2016 21:43:37 -0500 (EST) Received: by mail-yk0-f170.google.com with SMTP id a85so555625863ykb.1 for ; Mon, 18 Jan 2016 18:43:37 -0800 (PST) Received: from mail-yk0-x229.google.com (mail-yk0-x229.google.com. [2607:f8b0:4002:c07::229]) by mx.google.com with ESMTPS id q128si16225220ywe.171.2016.01.18.18.43.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Jan 2016 18:43:37 -0800 (PST) Received: by mail-yk0-x229.google.com with SMTP id k129so611017671yke.0 for ; Mon, 18 Jan 2016 18:43:37 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <1453125834-16546-1-git-send-email-liangchen.linux@gmail.com> Date: Tue, 19 Jan 2016 10:43:36 +0800 Message-ID: Subject: Re: [PATCH] mm:mempolicy: skip VM_HUGETLB and VM_MIXEDMAP VMA for lazy mbind From: Gavin Guo Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: SeongJae Park Cc: Liang Chen , n-horiguchi@ah.jp.nec.com, linux-mm@kvack.org, riel@redhat.com, Mel Gorman , Andrew Morton , linux-kernel Hi SeongJae, On Tue, Jan 19, 2016 at 9:12 AM, SeongJae Park wrote: > Hello Liang, > > Just trivial comment below. > > On Mon, 18 Jan 2016, Liang Chen wrote: > >> VM_HUGETLB and VM_MIXEDMAP vma needs to be excluded to avoid compound >> pages being marked for migration and unexpected COWs when handling >> hugetlb fault. >> >> Thanks to Naoya Horiguchi for reminding me on these checks. >> >> Signed-off-by: Liang Chen >> Signed-off-by: Gavin Guo >> --- >> mm/mempolicy.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/mm/mempolicy.c b/mm/mempolicy.c >> index 436ff411..415de70 100644 >> --- a/mm/mempolicy.c >> +++ b/mm/mempolicy.c >> @@ -610,8 +610,9 @@ 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_migratable(vma) && >> - vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) >> + if (vma_migratable(vma) && !is_vm_hugetlb_page(vma) && >> + (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) >> && >> + !(vma->vm_flags & VM_MIXEDMAP)) > > > Isn't there exists few unnecessary parenthesis? IMHO, it makes me hard to > read the code. > > How about below code, instead? > > + if (vma_migratable(vma) && !is_vm_hugetlb_page(vma) && > + vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE) && Thanks for your suggestion, it's good for the above. However, it should be a typo for the following and I think you mean: ~vma->vm_flags & VM_MIXEDMAP Even though the result is correct, I feel it's a bit of ambiguous for people to understand and away from it's original meaning. > + !vma->vm_flags & VM_MIXEDMAP) > > > Thanks, > SeongJae Park. > >> 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 >> > -- 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