From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx197.postini.com [74.125.245.197]) by kanga.kvack.org (Postfix) with SMTP id 3BC186B0034 for ; Tue, 11 Jun 2013 19:22:49 -0400 (EDT) Date: Tue, 11 Jun 2013 17:53:20 -0400 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [PATCH, RFC] mm: Implement RLIMIT_RSS Message-ID: <20130611215319.GA29368@logfs.org> References: <20130611182921.GB25941@logfs.org> <20130611211601.GA29426@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20130611211601.GA29426@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, 11 June 2013 17:16:01 -0400, Johannes Weiner wrote: > On Tue, Jun 11, 2013 at 02:29:21PM -0400, JA?rn Engel wrote: > > I've seen a couple of instances where people try to impose a vsize > > limit simply because there is no rss limit in Linux. The vsize limit > > is a horrible approximation and even this patch seems to be an > > improvement. > > > > Would there be strong opposition to actually supporting RLIMIT_RSS? > > This is trivial to exploit by creating the mappings first and > populating them later, so while it may cover some use cases, it does > not have the protection against malicious programs aspect that all the > other rlimits have. Hm. The use case I have is that an application wants to limit itself. It is effectively a special assert to catch memory leaks and the like. So malicious programs are not my immediate concern. Of course the moment Linux supports RLIMIT_RSS people will use it to limit malicious programs, no matter how many scary warning we put in. > The right place to enforce the limit is at the point of memory > allocation, which raises the question what to do when the limit is > exceeded in a page fault. Reclaim from the process's memory? Kill > it? > > I guess the answer to these questions is "memory cgroups", so that's > why there is no real motivation to implement RLIMIT_RSS separately... Lack of opposition would be enough for me. But I guess we need a bit more for a mergeable patch than I did and I only did the existing patch because it seemed easy, not because it is important. Will keep the patch in my junk code folder for now. JA?rn -- A surrounded army must be given a way out. -- Sun Tzu -- 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