From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f72.google.com (mail-it0-f72.google.com [209.85.214.72]) by kanga.kvack.org (Postfix) with ESMTP id DF3536B0069 for ; Mon, 22 Aug 2016 04:30:18 -0400 (EDT) Received: by mail-it0-f72.google.com with SMTP id i64so133051093ith.0 for ; Mon, 22 Aug 2016 01:30:18 -0700 (PDT) Received: from smtprelay.hostedemail.com (smtprelay0150.hostedemail.com. [216.40.44.150]) by mx.google.com with ESMTPS id y140si18447489iof.226.2016.08.22.01.30.18 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 22 Aug 2016 01:30:18 -0700 (PDT) Message-ID: <1471854614.3746.46.camel@perches.com> Subject: Re: [PATCH 2/2] proc: task_mmu: Reduce output processing cpu time From: Joe Perches Date: Mon, 22 Aug 2016 01:30:14 -0700 In-Reply-To: <1471852859.3746.42.camel@perches.com> References: <2c1ea0d8f35fa5ddea477369b273d6d91c5bf2e2.1471679737.git.joe@perches.com> <20160822072414.GB13596@dhcp22.suse.cz> <1471852859.3746.42.camel@perches.com> Content-Type: text/plain; charset="ISO-8859-1" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-kernel@vger.kernel.org, Andrew Morton , Jann Horn , linux-mm@kvack.org On Mon, 2016-08-22 at 01:00 -0700, Joe Perches wrote: > On Mon, 2016-08-22 at 09:24 +0200, Michal Hocko wrote: > > On Sat 20-08-16 01:00:17, Joe Perches wrote: [] > > > static int proc_maps_open(struct inode *inode, struct file *file, > > > const struct seq_operations *ops, int psize) > > > { > > > - struct proc_maps_private *priv = __seq_open_private(file, ops, psize); > > > + struct proc_maps_private *priv; > > > + struct mm_struct *mm; > > > + > > > + mm = proc_mem_open(inode, PTRACE_MODE_READ); > > > + if (IS_ERR(mm)) > > > + return PTR_ERR(mm); > > > > > > + priv = __seq_open_private_bufsize(file, ops, psize, > > > + mm && mm->map_count ? > > > + mm->map_count * 0x300 : PAGE_SIZE); > > NAK to this! > > > > Seriously, this just gives any random user access to user > > defined amount of memory which not accounted, not reclaimable and a > > potential consumer of any higher order blocks. > I completely disagree here with your rationale here. And with further review and your comment above, I withdraw this patch. cheers, Joe -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932234AbcHVIaV (ORCPT ); Mon, 22 Aug 2016 04:30:21 -0400 Received: from smtprelay0251.hostedemail.com ([216.40.44.251]:40463 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932167AbcHVIaT (ORCPT ); Mon, 22 Aug 2016 04:30:19 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::,RULES_HIT:41:355:379:541:599:973:988:989:1260:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2110:2198:2199:2393:2559:2562:2731:2828:2901:2911:3138:3139:3140:3141:3142:3352:3622:3866:3867:3868:4321:4425:5007:9040:10004:10400:10450:10455:10848:11026:11232:11473:11658:11783:11914:12043:12296:12438:12517:12519:12740:13069:13153:13228:13311:13357:13439:13869:13894:14659:14721:19904:19999:21080:30005:30051:30054:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:4,LUA_SUMMARY:none X-HE-Tag: straw38_59be3cbbdc150 X-Filterd-Recvd-Size: 2058 Message-ID: <1471854614.3746.46.camel@perches.com> Subject: Re: [PATCH 2/2] proc: task_mmu: Reduce output processing cpu time From: Joe Perches To: Michal Hocko Cc: linux-kernel@vger.kernel.org, Andrew Morton , Jann Horn , linux-mm@kvack.org Date: Mon, 22 Aug 2016 01:30:14 -0700 In-Reply-To: <1471852859.3746.42.camel@perches.com> References: <2c1ea0d8f35fa5ddea477369b273d6d91c5bf2e2.1471679737.git.joe@perches.com> <20160822072414.GB13596@dhcp22.suse.cz> <1471852859.3746.42.camel@perches.com> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.18.5.2-0ubuntu3 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2016-08-22 at 01:00 -0700, Joe Perches wrote: > On Mon, 2016-08-22 at 09:24 +0200, Michal Hocko wrote: > > On Sat 20-08-16 01:00:17, Joe Perches wrote: [] > > > static int proc_maps_open(struct inode *inode, struct file *file, > > >   const struct seq_operations *ops, int psize) > > >  { > > > - struct proc_maps_private *priv = __seq_open_private(file, ops, psize); > > > + struct proc_maps_private *priv; > > > + struct mm_struct *mm; > > > + > > > + mm = proc_mem_open(inode, PTRACE_MODE_READ); > > > + if (IS_ERR(mm)) > > > + return PTR_ERR(mm); > > >   > > > + priv = __seq_open_private_bufsize(file, ops, psize, > > > +   mm && mm->map_count ? > > > +   mm->map_count * 0x300 : PAGE_SIZE); > > NAK to this! > > > > Seriously, this just gives any random user access to user > > defined amount of memory which not accounted, not reclaimable and a > > potential consumer of any higher order blocks. > I completely disagree here with your rationale here. And with further review and your comment above, I withdraw this patch. cheers, Joe