From owner-cvs-src@FreeBSD.ORG Fri Jun 6 23:25:45 2008 Return-Path: Delivered-To: cvs-src@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DFDA81065672; Fri, 6 Jun 2008 23:25:45 +0000 (UTC) (envelope-from alc@cs.rice.edu) Received: from mail.cs.rice.edu (mail.cs.rice.edu [128.42.1.31]) by mx1.freebsd.org (Postfix) with ESMTP id C980D8FC16; Fri, 6 Jun 2008 23:25:45 +0000 (UTC) (envelope-from alc@cs.rice.edu) Received: from mail.cs.rice.edu (localhost.localdomain [127.0.0.1]) by mail.cs.rice.edu (Postfix) with ESMTP id 3BFD62C2D1F; Fri, 6 Jun 2008 18:06:08 -0500 (CDT) X-Virus-Scanned: by amavis-2.4.0 at mail.cs.rice.edu Received: from mail.cs.rice.edu ([127.0.0.1]) by mail.cs.rice.edu (mail.cs.rice.edu [127.0.0.1]) (amavisd-new, port 10024) with LMTP id B8froHUGxVgt; Fri, 6 Jun 2008 18:06:00 -0500 (CDT) Received: from [10.194.94.15] (nat-168-7-245-52.rice.edu [168.7.245.52]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.cs.rice.edu (Postfix) with ESMTP id 7BE642C2D0A; Fri, 6 Jun 2008 18:06:00 -0500 (CDT) Message-ID: <4849C2D0.9060704@cs.rice.edu> Date: Fri, 06 Jun 2008 18:05:52 -0500 From: Alan Cox User-Agent: Thunderbird 2.0.0.14 (Windows/20080421) MIME-Version: 1.0 To: Poul-Henning Kamp References: <1809.1212779481@critter.freebsd.dk> In-Reply-To: <1809.1212779481@critter.freebsd.dk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Alan Cox , cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/vm vm_page.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Jun 2008 23:25:46 -0000 Poul-Henning Kamp wrote: > In message <200806061838.m56Icu2E074642@repoman.freebsd.org>, Alan Cox writes: > >> alc 2008-06-06 18:38:43 UTC >> >> FreeBSD src repository >> >> Modified files: >> sys/vm vm_page.c >> Log: >> SVN rev 179623 on 2008-06-06 18:38:43Z by alc >> >> Essentially, neither madvise(..., MADV_DONTNEED) nor madvise(..., MADV_FREE) >> work. (Moreover, I don't believe that they have ever worked as intended.) >> > > I remember they did have a measurable but minor impact on performance > in systems which paged a lot, back when they were introduced, sort > of 1995-ish. But with the subsequent plunge in RAM prices they > never saw much use. > > After more thorough digging through CVS history, I now believe that MADV_DONTNEED worked properly between revision 1.70 (May 1996) and 1.76 (June 1996) of vm/vm_object.c. :-) It's more difficult to say for MADV_FREE. It may have been effective until 1999. Alan