From owner-cvs-all Sun Oct 10 18: 4:33 1999 Delivered-To: cvs-all@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id AC55914D27; Sun, 10 Oct 1999 18:04:15 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id SAA18509; Sun, 10 Oct 1999 18:04:12 -0700 (PDT) (envelope-from dillon) Date: Sun, 10 Oct 1999 18:04:12 -0700 (PDT) From: Matthew Dillon Message-Id: <199910110104.SAA18509@apollo.backplane.com> To: Poul-Henning Kamp Cc: Peter Wemm , "Daniel C. Sobral" , cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/vm vm_swap.c References: <15735.939576321@critter.freebsd.dk> Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk :> If you implement a means to create unassociated (i.e. no major/minor :> number at all) devices, the swap device can be converted to one :> internally. We aren't going to get rid of the cdevsw structure, though. :> Creating totally custom I/O interfaces is never a good idea. : :You don't need a dev_t, in fact one or two levels of indirection through :vnop/devsw can be ripped right out by calling swstrategy() directly. : :-- :Poul-Henning Kamp FreeBSD coreteam member We're not removing the device interface. It provides a reasonable abstraction and a nice demark between swap_pager.c and vm_swap.c, as well as potential flexibility that could be useful in the future Removing it will not save time or much in the way of code space. As far as the striping efficiency goes: The swap device abstraction is already massively tuned for I/O efficiency, nothing you could possibly do with a ccd or vinum will make it better. Additionally, there are complexities related not only to the swapon code, but to (potentially) future swapoff and prioritization calls that are not suited to other pre-existing abstractions (such as vinum or ccd). -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message