From owner-freebsd-current Mon Dec 4 16: 9:11 2000 From owner-freebsd-current@FreeBSD.ORG Mon Dec 4 16:09:09 2000 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 9B14D37B400 for ; Mon, 4 Dec 2000 16:09:08 -0800 (PST) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id QAA20858; Mon, 4 Dec 2000 16:05:22 -0800 (PST) Message-Id: <200012050005.QAA20858@implode.root.com> To: Bernd Walter Cc: janb@cs.utep.edu, freebsd-current@FreeBSD.ORG Subject: Re: current paging strategy In-reply-to: Your message of "Sun, 05 Nov 2000 17:57:46 +0100." <20001105175745.A42346@cicely8.cicely.de> From: David Greenman Reply-To: dg@root.com Date: Mon, 04 Dec 2000 16:05:22 -0800 Sender: dg@implode.root.com Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >On Thu, Nov 02, 2000 at 12:45:30AM -0800, David Greenman wrote: >> >Interesting. THis needs about two bytes per page for the counter? >> >> Actually, we found that a single byte per page was sufficient. Pages tended >> to be either heavily accessed or rarely accessed. Even in the unusual case >> where all pages are frequently accessed, the page reclaim rate (and thus >> adjustment rate of the page references count) increases high enough to still >> provide for a decent distribution of the counters and for the page LOU to be >> effective. > >One byte sounds good for i386. >Maybe it makes sense to have it 4 or 8 byte on risc platforms. >I wonder if it's a critical path and if there are more of this in >the kernel source. No, space consumption of the vm_page data structure is by far the greatest concern. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message