From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161209AbcIWPy4 (ORCPT ); Fri, 23 Sep 2016 11:54:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50994 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966273AbcIWPyw (ORCPT ); Fri, 23 Sep 2016 11:54:52 -0400 Date: Fri, 23 Sep 2016 17:53:51 +0200 From: Oleg Nesterov To: Michal Hocko Cc: Robert Ho , pbonzini@redhat.com, akpm@linux-foundation.org, dan.j.williams@intel.com, dave.hansen@intel.com, guangrong.xiao@linux.intel.com, gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stefanha@redhat.com, yuhuang@redhat.com, linux-mm@kvack.org, ross.zwisler@linux.intel.com Subject: Re: [PATCH v3 1/2] mm, proc: Fix region lost in /proc/self/smaps Message-ID: <20160923155351.GA1584@redhat.com> References: <1474636354-25573-1-git-send-email-robert.hu@intel.com> <20160923135635.GB28734@redhat.com> <20160923145301.GU4478@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160923145301.GU4478@dhcp22.suse.cz> User-Agent: Mutt/1.5.18 (2008-05-17) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 23 Sep 2016 15:54:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/23, Michal Hocko wrote: > > On Fri 23-09-16 15:56:36, Oleg Nesterov wrote: > > > > I think we can simplify this patch. And imo make it better. How about > > it is certainly less subtle because it doesn't report "sub-vmas". > > > if (last_addr) { > > vma = find_vma(mm, last_addr - 1); > > if (vma && vma->vm_start <= last_addr) > > vma = m_next_vma(priv, vma); > > if (vma) > > return vma; > > } > > we would still miss a VMA if the last one got shrunk/split Not sure I understand what you mean... If the last one was split we probably should not report the new vma. Nevermind, in any case yes, sure, this can't "fix" other corner cases. > So definitely an improvement but > I guess we really want to document that only full reads provide a > consistent (at some moment in time) output. or all the threads were stopped. Agreed. And again, this applies to any file in /proc. Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Nesterov Subject: Re: [PATCH v3 1/2] mm, proc: Fix region lost in /proc/self/smaps Date: Fri, 23 Sep 2016 17:53:51 +0200 Message-ID: <20160923155351.GA1584@redhat.com> References: <1474636354-25573-1-git-send-email-robert.hu@intel.com> <20160923135635.GB28734@redhat.com> <20160923145301.GU4478@dhcp22.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Robert Ho , pbonzini@redhat.com, akpm@linux-foundation.org, dan.j.williams@intel.com, dave.hansen@intel.com, guangrong.xiao@linux.intel.com, gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stefanha@redhat.com, yuhuang@redhat.com, linux-mm@kvack.org, ross.zwisler@linux.intel.com To: Michal Hocko Return-path: Content-Disposition: inline In-Reply-To: <20160923145301.GU4478@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-Id: kvm.vger.kernel.org On 09/23, Michal Hocko wrote: > > On Fri 23-09-16 15:56:36, Oleg Nesterov wrote: > > > > I think we can simplify this patch. And imo make it better. How about > > it is certainly less subtle because it doesn't report "sub-vmas". > > > if (last_addr) { > > vma = find_vma(mm, last_addr - 1); > > if (vma && vma->vm_start <= last_addr) > > vma = m_next_vma(priv, vma); > > if (vma) > > return vma; > > } > > we would still miss a VMA if the last one got shrunk/split Not sure I understand what you mean... If the last one was split we probably should not report the new vma. Nevermind, in any case yes, sure, this can't "fix" other corner cases. > So definitely an improvement but > I guess we really want to document that only full reads provide a > consistent (at some moment in time) output. or all the threads were stopped. Agreed. And again, this applies to any file in /proc. Oleg. -- 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