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From: Scott Long <scottl@samsco.org>
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Date: Sat, 17 Apr 2010 16:49:36 -0600
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To: Poul-Henning Kamp <phk@phk.freebsd.dk>
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Cc: Attilio Rao <attilio@freebsd.org>,
	Giovanni Trematerra <giovanni.trematerra@gmail.com>,
	freebsd-arch@freebsd.org
Subject: Re: [PATCH] Syncer rewriting 
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On Apr 16, 2010, at 2:23 AM, Poul-Henning Kamp wrote:
>=20
>=20
>> - 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.
>=20
> 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.
>=20
> 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.

Scott