From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 599996B003D for ; Fri, 8 May 2009 12:04:52 -0400 (EDT) Message-ID: <4A04580B.5050501@redhat.com> Date: Fri, 08 May 2009 12:04:27 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen References: <20090501123541.7983a8ae.akpm@linux-foundation.org> <20090503031539.GC5702@localhost> <1241432635.7620.4732.camel@twins> <20090507121101.GB20934@localhost> <1241705702.11251.156.camel@twins> <1241712000.18617.7.camel@lts-notebook> <4A03164D.90203@redhat.com> <20090508034054.GB1202@eskimo.com> In-Reply-To: <20090508034054.GB1202@eskimo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Elladan Cc: Christoph Lameter , Lee Schermerhorn , Peter Zijlstra , Wu Fengguang , Andrew Morton , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , Nick Piggin , Johannes Weiner , KOSAKI Motohiro List-ID: Elladan wrote: >> Nobody (except you) is proposing that we completely disable >> the eviction of executable pages. I believe that your idea >> could easily lead to a denial of service attack, with a user >> creating a very large executable file and mmaping it. >> >> Giving executable pages some priority over other file cache >> pages is nowhere near as dangerous wrt. unexpected side effects >> and should work just as well. > > I don't think this sort of DOS is relevant for a single user or trusted user > system. Which not all systems are, meaning that the mechanism Christoph proposes can never be enabled by default and would have to be tweaked by the user. I prefer code that should work just as well 99% of the time, but can be enabled by default for everybody. That way people automatically get the benefit. -- All rights reversed. -- 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