Date: Fri, 21 Dec 2012 09:38:01 -0800 From: Alfred Perlstein <bright@mu.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Ivan Voras <ivoras@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: Unmapped I/O Message-ID: <50D49E79.6090500@mu.org> In-Reply-To: <20121221120237.GF53644@kib.kiev.ua> References: <20121219135451.GU71906@kib.kiev.ua> <kauqfc$rau$1@ger.gmane.org> <20121220201523.GD53644@kib.kiev.ua> <CAF-QHFXdeG0ZHOp1L5TQ25t4maruz3=pmFEco0x8mMqcR-Mr=w@mail.gmail.com> <20121221120237.GF53644@kib.kiev.ua>
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On 12/21/12 4:02 AM, Konstantin Belousov wrote: > On Fri, Dec 21, 2012 at 12:52:35PM +0100, Ivan Voras wrote: >> On 20 December 2012 21:15, Konstantin Belousov <kostikbel@gmail.com> wrote: >> >>> Nothing is changed for existing GEOM classes, and it does not mean anything >>> for GEOM developers, unless she wants to change the GEOM class to handle >>> unmapped BIOs. >> Understood, but the intention of my question was: do you recommend >> GEOM classes should take the effort and implement unmapped BIOs >> whenever possible? > Depends. RAID 0 and RAID 1 can process unmapped BIOs without changes, > I am sure. For the class like RAID5, you would need a hardware > for it to be able to operate on the unmapped BIOs without requiring > the remap. There is indeed Intel IOAT, which I believe can do this. > > On the other hand, for encrypting classes like GELI it probably does not > make much sense to care, for the case of encryption done in software or > using AES-NI. *Raising my hand like the annoying kid in class* What about asking for the physaddr for such pages on dmap arches? by the way, thanks for this giant leap forward, it's going to help FreeBSD very much! -Alfred
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