From owner-cvs-all Sun Sep 19 12: 9:36 1999 Delivered-To: cvs-all@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.40.131]) by hub.freebsd.org (Postfix) with ESMTP id C414015227; Sun, 19 Sep 1999 12:09:28 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.9.3/8.9.2) with ESMTP id VAA17521; Sun, 19 Sep 1999 21:07:00 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Matthew Dillon Cc: Matthew Jacob , dg@root.com, Greg Lehey , cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: User block device access In-reply-to: Your message of "Sun, 19 Sep 1999 12:00:26 PDT." <199909191900.MAA73792@apollo.backplane.com> Date: Sun, 19 Sep 1999 21:07:00 +0200 Message-ID: <17519.937768020@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk In message <199909191900.MAA73792@apollo.backplane.com>, Matthew Dillon writes: > In fact, a memory-mappable buffered block device with write-through would > be much, much more useful to a database then a character device, and I > think it's only a two line patch to make mmap() work, and probably a > four line patch to implement write-through. It would be virtually > unbeatable... use of mmap() removes the extra copy overhead, read-caching > takes the burden off the application, optional write-through gives you > instant feedback *AND* reblocking. I would even be willing to make the > write-through the default. > > That would give us an extremely powerful and useful buffered block device > implementation. Now that is the kind of attitude I like to work with: constructive and full of good ideas. Thankyou Matt! So you are saying that we could basically leave read/write as they are for cdevs and provide the buffer/cache mechanisms with mmap ? -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message