From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752662AbdKFMMZ (ORCPT ); Mon, 6 Nov 2017 07:12:25 -0500 Received: from mx2.suse.de ([195.135.220.15]:58677 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752076AbdKFMMY (ORCPT ); Mon, 6 Nov 2017 07:12:24 -0500 Date: Mon, 6 Nov 2017 13:12:22 +0100 From: Michal Hocko To: Peter Zijlstra Cc: Bart Van Assche , "yang.s@alibaba-inc.com" , "akpm@linux-foundation.org" , "joe@perches.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "mingo@redhat.com" Subject: Re: [PATCH] mm: use in_atomic() in print_vma_addr() Message-ID: <20171106121222.nnzrr4cb7s7y5h74@dhcp22.suse.cz> References: <1509572313-102989-1-git-send-email-yang.s@alibaba-inc.com> <20171102075744.whhxjmqbdkfaxghd@dhcp22.suse.cz> <20171103110245.7049460a05cc18c7e8a9feb2@linux-foundation.org> <1509739786.2473.33.camel@wdc.com> <20171105081946.yr2pvalbegxygcky@dhcp22.suse.cz> <20171106100558.GD3165@worktop.lehotels.local> <20171106104354.2jlgd2m4j4gxx4qo@dhcp22.suse.cz> <20171106120025.GH3165@worktop.lehotels.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171106120025.GH3165@worktop.lehotels.local> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 06-11-17 13:00:25, Peter Zijlstra wrote: > On Mon, Nov 06, 2017 at 11:43:54AM +0100, Michal Hocko wrote: > > > Yes the comment is very much accurate. > > > > Which suggests that print_vma_addr might be problematic, right? > > Shouldn't we do trylock on mmap_sem instead? > > Yes that's complete rubbish. trylock will get spurious failures to print > when the lock is contended. Yes, but I guess that it is acceptable to to not print the state under that condition. -- Michal Hocko SUSE Labs