From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966911AbbLPRn4 (ORCPT ); Wed, 16 Dec 2015 12:43:56 -0500 Received: from mail-lb0-f177.google.com ([209.85.217.177]:34652 "EHLO mail-lb0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966900AbbLPRnx (ORCPT ); Wed, 16 Dec 2015 12:43:53 -0500 Date: Wed, 16 Dec 2015 19:43:49 +0200 From: "Kirill A. Shutemov" To: Oleg Nesterov Cc: Andrew Morton , "Kirill A. Shutemov" , Naoya Horiguchi , Cyrill Gorcunov , linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() Message-ID: <20151216174348.GA19144@node.shutemov.name> References: <20151216172632.GA7589@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151216172632.GA7589@redhat.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 16, 2015 at 06:26:32PM +0100, Oleg Nesterov wrote: > clear_soft_dirty_pmd() is called by clear_refs_write(CLEAR_REFS_SOFT_DIRTY), > VM_SOFTDIRTY was already cleared before walk_page_range(). Not only that, We shouldn't [generally] change vm_flags without exclusive mmap_sem and we have only down_read() here. > Signed-off-by: Oleg Nesterov Acked-by: Kirill A. Shutemov > --- > fs/proc/task_mmu.c | 3 --- > 1 files changed, 0 insertions(+), 3 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 187b3b5..1a02b15 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -817,9 +817,6 @@ static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma, > pmd = pmd_wrprotect(pmd); > pmd = pmd_clear_soft_dirty(pmd); > > - if (vma->vm_flags & VM_SOFTDIRTY) > - vma->vm_flags &= ~VM_SOFTDIRTY; > - > set_pmd_at(vma->vm_mm, addr, pmdp, pmd); > } > #else > -- > 1.5.5.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Kirill A. Shutemov