From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 430236B027F for ; Mon, 26 Sep 2016 04:46:19 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id w84so76198141wmg.1 for ; Mon, 26 Sep 2016 01:46:19 -0700 (PDT) Received: from mail-wm0-f68.google.com (mail-wm0-f68.google.com. [74.125.82.68]) by mx.google.com with ESMTPS id l70si7614704wmg.18.2016.09.26.01.46.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Sep 2016 01:46:17 -0700 (PDT) Received: by mail-wm0-f68.google.com with SMTP id b184so12966441wma.3 for ; Mon, 26 Sep 2016 01:46:17 -0700 (PDT) Date: Mon, 26 Sep 2016 10:46:16 +0200 From: Michal Hocko Subject: Re: [PATCH v3 1/2] mm, proc: Fix region lost in /proc/self/smaps Message-ID: <20160926084616.GA28550@dhcp22.suse.cz> References: <1474636354-25573-1-git-send-email-robert.hu@intel.com> <20160923135635.GB28734@redhat.com> <20160923145301.GU4478@dhcp22.suse.cz> <20160923155351.GA1584@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160923155351.GA1584@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov 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 On Fri 23-09-16 17:53:51, Oleg Nesterov wrote: > 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. Right, VMA split is less of a problem. I meant to say that if the last_vma->vm_end got lower for whatever reason then we could miss a VMA right after. We actually might want to display such a VMA because it could be a completely new one. We just do not know whether it is a former split with enlarged VMA or a completely new one [ old VMA ] Hole [ VMA ] [ old VMA ][ New VMa ] [ VMA ] > Nevermind, in any case yes, sure, this can't "fix" other corner cases. Agreed, or at least I do not see an easy way for that. -- Michal Hocko SUSE Labs -- 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