From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 8D7BC6B003D for ; Thu, 7 May 2009 10:15:00 -0400 (EDT) Subject: Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen From: Peter Zijlstra In-Reply-To: References: <20090430072057.GA4663@eskimo.com> <20090430174536.d0f438dd.akpm@linux-foundation.org> <20090430205936.0f8b29fc@riellaptop.surriel.com> <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> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Thu, 07 May 2009 16:15:02 +0200 Message-Id: <1241705702.11251.156.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: Wu Fengguang , Andrew Morton , Rik van Riel , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , Elladan , Nick Piggin , Johannes Weiner , KOSAKI Motohiro List-ID: On Thu, 2009-05-07 at 09:39 -0400, Christoph Lameter wrote: > On Thu, 7 May 2009, Wu Fengguang wrote: > > > Introduce AS_EXEC to mark executables and their linked libraries, and to > > protect their referenced active pages from being deactivated. > > > We already have support for mlock(). How is this an improvement? This is > worse since the AS_EXEC pages stay on the active list and are continually > rescanned. It re-instates the young bit for PROT_EXEC pages, so that they will only be paged when they are really cold, or there is severe pressure. This simply gives them an edge over regular data. I don't think the extra scanning is a problem, since you rarely have huge amounts of executable pages around. mlock()'ing all code just doesn't sound like a good alternative. -- 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