From owner-freebsd-hackers@FreeBSD.ORG Mon Jul 26 19:59:35 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D62DF106564A for ; Mon, 26 Jul 2010 19:59:35 +0000 (UTC) (envelope-from avg@freebsd.org) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 282C08FC15 for ; Mon, 26 Jul 2010 19:59:34 +0000 (UTC) Received: from porto.topspin.kiev.ua (porto-e.starpoint.kiev.ua [212.40.38.100]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id WAA29983; Mon, 26 Jul 2010 22:59:32 +0300 (EEST) (envelope-from avg@freebsd.org) Received: from localhost.topspin.kiev.ua ([127.0.0.1]) by porto.topspin.kiev.ua with esmtp (Exim 4.34 (FreeBSD)) id 1OdTpk-000HAo-HB; Mon, 26 Jul 2010 22:59:32 +0300 Message-ID: <4C4DE923.5030307@freebsd.org> Date: Mon, 26 Jul 2010 22:59:31 +0300 From: Andriy Gapon User-Agent: Thunderbird 2.0.0.24 (X11/20100603) MIME-Version: 1.0 To: RW References: <4C4B4BAB.3000005@freebsd.org> <20100725003144.3cfead39@gumby.homeunix.com> <4C4C0CD9.6000002@freebsd.org> <20100725144141.6f1f33cc@gumby.homeunix.com> <4C4C47FD.6080802@freebsd.org> <20100725212849.1e07f40c@gumby.homeunix.com> <4C4CA1DC.2050902@freebsd.org> <20100726185348.63ebf916@gumby.homeunix.com> In-Reply-To: <20100726185348.63ebf916@gumby.homeunix.com> X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@freebsd.org Subject: Re: pageout question X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Jul 2010 19:59:35 -0000 on 26/07/2010 20:53 RW said the following: > If after the first pass with light-paging the high watermark isn't > reached then the choices are > > 1) loop and immediately do a heavy-paging pass. > > 2) wait and let the daemon get woken-up for another light-paging pass - > only go to heavy-paging when this strategy isn't keeping up with demand. > > To me (2) is doing the right thing. It's trying to satisfy demand from > existing clean pages, and only paging heavily as a last resort. Well, based on my observations, if the first pass doesn't reach the high watermark, then we are in a high pressure situation and so we would have to do some heavy-lifting anyways. In my opinion, it's better to start doing more work at once than trying to pretend that situation would somehow resolve itself. -- Andriy Gapon