From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757808AbZEHWW7 (ORCPT ); Fri, 8 May 2009 18:22:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752136AbZEHWWv (ORCPT ); Fri, 8 May 2009 18:22:51 -0400 Received: from mx2.redhat.com ([66.187.237.31]:39580 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751481AbZEHWWu (ORCPT ); Fri, 8 May 2009 18:22:50 -0400 Message-ID: <4A04B021.10004@redhat.com> Date: Fri, 08 May 2009 18:20:17 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 2.0.0.17 (X11/20080915) MIME-Version: 1.0 To: Alan Cox CC: Andrew Morton , Wu Fengguang , hannes@cmpxchg.org, peterz@infradead.org, linux-kernel@vger.kernel.org, tytso@mit.edu, linux-mm@kvack.org, elladan@eskimo.com, npiggin@suse.de, cl@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, minchan.kim@gmail.com Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen References: <20090430181340.6f07421d.akpm@linux-foundation.org> <20090430215034.4748e615@riellaptop.surriel.com> <20090430195439.e02edc26.akpm@linux-foundation.org> <49FB01C1.6050204@redhat.com> <20090501123541.7983a8ae.akpm@linux-foundation.org> <20090503031539.GC5702@localhost> <1241432635.7620.4732.camel@twins> <20090507121101.GB20934@localhost> <20090507151039.GA2413@cmpxchg.org> <20090507134410.0618b308.akpm@linux-foundation.org> <20090508081608.GA25117@localhost> <20090508125859.210a2a25.akpm@linux-foundation.org> <20090508230045.5346bd32@lxorguk.ukuu.org.uk> In-Reply-To: <20090508230045.5346bd32@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: >> The patch seems reasonable but the changelog and the (non-existent) >> design documentation could do with a touch-up. > > Is it right that I as a user can do things like mmap my database > PROT_EXEC to get better database numbers by making other > stuff swap first ? Yes, but only if your SELinux policy allows you to mmap something that's both executable and writable at the same time. > You seem to be giving everyone a "nice my process up" hack. A user who wants to slow the system down has always been able to do so. I am not convinced that the potential disadvantages of giving mapped referenced executable file pages an extra round trip on the active file list outweighs the advantages of doing so for normal workloads. -- All rights reversed. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 4EA2E6B0098 for ; Fri, 8 May 2009 18:20:55 -0400 (EDT) Message-ID: <4A04B021.10004@redhat.com> Date: Fri, 08 May 2009 18:20:17 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen References: <20090430181340.6f07421d.akpm@linux-foundation.org> <20090430215034.4748e615@riellaptop.surriel.com> <20090430195439.e02edc26.akpm@linux-foundation.org> <49FB01C1.6050204@redhat.com> <20090501123541.7983a8ae.akpm@linux-foundation.org> <20090503031539.GC5702@localhost> <1241432635.7620.4732.camel@twins> <20090507121101.GB20934@localhost> <20090507151039.GA2413@cmpxchg.org> <20090507134410.0618b308.akpm@linux-foundation.org> <20090508081608.GA25117@localhost> <20090508125859.210a2a25.akpm@linux-foundation.org> <20090508230045.5346bd32@lxorguk.ukuu.org.uk> In-Reply-To: <20090508230045.5346bd32@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Alan Cox Cc: Andrew Morton , Wu Fengguang , hannes@cmpxchg.org, peterz@infradead.org, linux-kernel@vger.kernel.org, tytso@mit.edu, linux-mm@kvack.org, elladan@eskimo.com, npiggin@suse.de, cl@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, minchan.kim@gmail.com List-ID: Alan Cox wrote: >> The patch seems reasonable but the changelog and the (non-existent) >> design documentation could do with a touch-up. > > Is it right that I as a user can do things like mmap my database > PROT_EXEC to get better database numbers by making other > stuff swap first ? Yes, but only if your SELinux policy allows you to mmap something that's both executable and writable at the same time. > You seem to be giving everyone a "nice my process up" hack. A user who wants to slow the system down has always been able to do so. I am not convinced that the potential disadvantages of giving mapped referenced executable file pages an extra round trip on the active file list outweighs the advantages of doing so for normal workloads. -- 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