From owner-freebsd-hackers Sat Jul 13 5:23:37 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1044E37B401 for ; Sat, 13 Jul 2002 05:23:35 -0700 (PDT) Received: from goose.mail.pas.earthlink.net (goose.mail.pas.earthlink.net [207.217.120.18]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9051043E5E for ; Sat, 13 Jul 2002 05:23:34 -0700 (PDT) (envelope-from tlambert2@mindspring.com) Received: from pool0019.cvx22-bradley.dialup.earthlink.net ([209.179.198.19] helo=mindspring.com) by goose.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 17TLvr-0007gZ-00; Sat, 13 Jul 2002 05:23:28 -0700 Message-ID: <3D301B93.F7CC4F1C@mindspring.com> Date: Sat, 13 Jul 2002 05:22:43 -0700 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: David Schultz Cc: Peter Wemm , Matthew Dillon , Sean Kelly , hackers@FreeBSD.ORG Subject: Re: swapoff? References: <20020713071911.GA1558@HAL9000.wox.org> <20020713073404.9869A3811@overcee.wemm.org> <20020713115746.GA2162@HAL9000.wox.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG David Schultz wrote: > The weight idea is very interesting. NetBSD does this using > priorities; all the swap devices of a given priority are filled > round robin before devices of lower priority, the idea being that > the slower ones are a last resort (e.g. NFS). On the other hand, > this design allows large and fast swap devices to start swapping > to death before the `backup' devices see any action. It isn't > clear to me whether priorities or "fill levels" are better. > (Certainly a hybrid is possible, that is, weights within priority > levels.) I like the idea of a moving average on time-from-request-to-service. 8-). Works great for Server Load Balancing, too. The moving average takes load into account, without explicit load notification (i.e. no need to have a load notification protocol between NFS clients and servers, etc.). > This may be a better project for me than swapoff in the immediate > future because I won't have to understand how to track down the > appropriate VM objects and handle them in a kosher manner. > Implementing weights/priorities will also involve dynamically > allocating struct swdevt's, which should be done anyway and will > only be harder after swapoff() is written. 8-). "Now that everyone is talking about it, better get my hacks in first, so that other people have to integrate with my changes, instead of the other way around"... Actually, I think it's a nice idea for an incremental project. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message