Date: Sat, 17 Apr 2010 16:08:57 -1000 (HST) From: Jeff Roberson <jroberson@jroberson.net> To: Scott Long <scottl@samsco.org> Cc: Attilio Rao <attilio@freebsd.org>, Poul-Henning Kamp <phk@phk.freebsd.dk>, Giovanni Trematerra <giovanni.trematerra@gmail.com>, freebsd-arch@freebsd.org Subject: Re: [PATCH] Syncer rewriting Message-ID: <alpine.BSF.2.00.1004171606410.1398@desktop> In-Reply-To: <F335207A-4AE3-4993-8CC7-16CCEE425BC4@samsco.org> References: <29917.1271406183@critter.freebsd.dk> <F335207A-4AE3-4993-8CC7-16CCEE425BC4@samsco.org>
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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" >
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