From owner-freebsd-arch@FreeBSD.ORG Sun Apr 18 02:37:30 2010 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 172D2106566C for ; Sun, 18 Apr 2010 02:37:29 +0000 (UTC) (envelope-from jroberson@jroberson.net) Received: from mail-gy0-f182.google.com (mail-gy0-f182.google.com [209.85.160.182]) by mx1.freebsd.org (Postfix) with ESMTP id 8FA558FC08 for ; Sun, 18 Apr 2010 02:37:29 +0000 (UTC) Received: by gyh20 with SMTP id 20so2071855gyh.13 for ; Sat, 17 Apr 2010 19:37:28 -0700 (PDT) Received: by 10.101.5.29 with SMTP id h29mr9519022ani.40.1271556537016; Sat, 17 Apr 2010 19:08:57 -0700 (PDT) Received: from [10.0.1.198] (udp022762uds.hawaiiantel.net [72.234.79.107]) by mx.google.com with ESMTPS id y6sm29683557ana.5.2010.04.17.19.08.54 (version=SSLv3 cipher=RC4-MD5); Sat, 17 Apr 2010 19:08:55 -0700 (PDT) Date: Sat, 17 Apr 2010 16:08:57 -1000 (HST) From: Jeff Roberson X-X-Sender: jroberson@desktop To: Scott Long In-Reply-To: Message-ID: References: <29917.1271406183@critter.freebsd.dk> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: Attilio Rao , Poul-Henning Kamp , Giovanni Trematerra , freebsd-arch@freebsd.org Subject: Re: [PATCH] Syncer rewriting X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Apr 2010 02:37:30 -0000 On Sat, 17 Apr 2010, Scott Long wrote: > On Apr 16, 2010, at 2:23 AM, Poul-Henning Kamp wrote: >> >> >>> - The standard syncer may be further improved getting rid of the >>> bufobj. It should actually handle a list of vnodes rather than a list >>> of bufobj. However similar optimizations may be done after the patch >>> is ready to enter the tree. >> >> That would be the wrong direction: we need the bufobj because for instance >> a RAID5 geom module does not have a vnode for the parity data. >> >> If you force the syncer to only work on vnodes, then we need a parallel >> mechanism for non-filesystem disk users. > > It's been 5-6 (7?) years since you invented the bufobj, but I still haven't seen > anything in GEOM use it as you suggest. You used to have a saying about > premature optimization... I'd like to see Attilio's work move forward despite this. > I tend to agree. I also think the syncer is inherently a vnode centric operation. RAID5 should have its own rules and optimizations for managing its dirty data. It would have to anyway to keep the disk state consistent. Wouldn't it be a write through cache anyway and only keep clean data in core? Thanks, Jeff > Scott > > _______________________________________________ > freebsd-arch@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org" >