From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id DE7116B0006 for ; Wed, 18 Apr 2018 05:03:18 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id i8-v6so724522plt.8 for ; Wed, 18 Apr 2018 02:03:18 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 9-v6si861372plb.415.2018.04.18.02.03.17 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 18 Apr 2018 02:03:17 -0700 (PDT) Date: Wed, 18 Apr 2018 11:03:14 +0200 From: Michal Hocko Subject: Re: [v4 PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct Message-ID: <20180418090314.GU17484@dhcp22.suse.cz> References: <1523730291-109696-1-git-send-email-yang.shi@linux.alibaba.com> <20180418080555.GR17484@dhcp22.suse.cz> <20180418090217.GG19578@uranus.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180418090217.GG19578@uranus.lan> Sender: owner-linux-mm@kvack.org List-ID: To: Cyrill Gorcunov Cc: Yang Shi , adobriyan@gmail.com, willy@infradead.org, mguzik@redhat.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed 18-04-18 12:02:17, Cyrill Gorcunov wrote: > On Wed, Apr 18, 2018 at 10:05:55AM +0200, Michal Hocko wrote: > > > > Yes, looks good to me. As mentioned in other emails prctl_set_mm_map > > really deserves a comment explaining why we are doing the down_read > > > > What about something like the following? > > " > > arg_lock protects concurent updates but we still need mmap_sem for read > > to exclude races with do_brk. > > " > > Acked-by: Michal Hocko > > Yes, thanks! Andrew, could you slightly update the changelog please? No, I meant it to be a comment in the _code_. -- Michal Hocko SUSE Labs