From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758262AbZELDBM (ORCPT ); Mon, 11 May 2009 23:01:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757609AbZELDA5 (ORCPT ); Mon, 11 May 2009 23:00:57 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:54979 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757570AbZELDA4 (ORCPT ); Mon, 11 May 2009 23:00:56 -0400 From: KOSAKI Motohiro To: Wu Fengguang Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , "hannes@cmpxchg.org" , "peterz@infradead.org" , "riel@redhat.com" , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "cl@linux-foundation.org" , "minchan.kim@gmail.com" In-Reply-To: <20090512025246.GC7518@localhost> References: <20090508125859.210a2a25.akpm@linux-foundation.org> <20090512025246.GC7518@localhost> Message-Id: <20090512120002.D616.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 12 May 2009 12:00:51 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > side effects > ------------ > > This patch is safe in general, it restores the pre-2.6.28 mmap() behavior > but in a much smaller and well targeted scope. > > One may worry about some one to abuse the PROT_EXEC heuristic. But as > Andrew Morton stated, there are other tricks to getting that sort of boost. > > Another concern is the PROT_EXEC mapped pages growing large in rare cases, > and therefore hurting reclaim efficiency. But a sane application targeted for > large audience will never use PROT_EXEC for data mappings. If some home made > application tries to abuse that bit, it shall be aware of the consequences, > which won't be disastrous even in the worst case. ok, I lose. if you can post good mesurement result, I'll ack this. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 08C2A6B005A for ; Mon, 11 May 2009 23:00:55 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n4C30s1d022490 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 12 May 2009 12:00:54 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id D925845DD83 for ; Tue, 12 May 2009 12:00:53 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 5DEA145DD81 for ; Tue, 12 May 2009 12:00:53 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3500A1DB8041 for ; Tue, 12 May 2009 12:00:53 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id B8D721DB803F for ; Tue, 12 May 2009 12:00:52 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen In-Reply-To: <20090512025246.GC7518@localhost> References: <20090508125859.210a2a25.akpm@linux-foundation.org> <20090512025246.GC7518@localhost> Message-Id: <20090512120002.D616.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 12 May 2009 12:00:51 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , "hannes@cmpxchg.org" , "peterz@infradead.org" , "riel@redhat.com" , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "cl@linux-foundation.org" , "minchan.kim@gmail.com" List-ID: > side effects > ------------ > > This patch is safe in general, it restores the pre-2.6.28 mmap() behavior > but in a much smaller and well targeted scope. > > One may worry about some one to abuse the PROT_EXEC heuristic. But as > Andrew Morton stated, there are other tricks to getting that sort of boost. > > Another concern is the PROT_EXEC mapped pages growing large in rare cases, > and therefore hurting reclaim efficiency. But a sane application targeted for > large audience will never use PROT_EXEC for data mappings. If some home made > application tries to abuse that bit, it shall be aware of the consequences, > which won't be disastrous even in the worst case. ok, I lose. if you can post good mesurement result, I'll ack this. -- 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