From: Gerd Hoffmann <kraxel@suse.de>
To: Muli Ben-Yehuda <mulix@mulix.org>
Cc: "Magenheimer,
Dan (HP Labs Fort Collins)" <dan.magenheimer@hp.com>,
xen-devel <xen-devel@lists.xensource.com>,
okrieg@us.ibm.com
Subject: Re: VP problematic for backend drivers on IA64?
Date: Wed, 25 Jan 2006 17:24:56 +0100 [thread overview]
Message-ID: <43D7A658.4020105@suse.de> (raw)
In-Reply-To: <20060125143732.GE24849@granada.merseine.nu>
Hi,
> I think it's a pretty ugly hack; struct page has a very specific
> meaning in Linux. Minimizing changes in Linux by subverting this
> meaning does not strike me as the right thing to do.
Well, not exactly nice indeed, but any other solution involves touching
all block drivers ...
> at all - Linux is never going to look at the page (kmap it). Having
Depends. If it's actually DMA'ing directly it doesn't, which should be
true in 99% of all cases. But there are some corner cases: If the
block layer needs bounce buffers it will attempt to kmap() the page to
copy the data. The same is true for drivers which don't DMA (floppy.c
for example).
cheers,
Gerd
--
Gerd 'just married' Hoffmann <kraxel@suse.de>
I'm the hacker formerly known as Gerd Knorr.
http://www.suse.de/~kraxel/just-married.jpeg
next prev parent reply other threads:[~2006-01-25 16:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-20 1:55 VP problematic for backend drivers on IA64? Muli Ben-Yehuda
2006-01-25 10:29 ` Gerd Hoffmann
2006-01-25 14:37 ` Muli Ben-Yehuda
2006-01-25 16:24 ` Gerd Hoffmann [this message]
2006-01-25 16:46 ` Muli Ben-Yehuda
2006-01-25 16:56 ` Keir Fraser
2006-01-25 17:54 ` Muli Ben-Yehuda
-- strict thread matches above, loose matches on Subject: below --
2006-01-20 17:08 Magenheimer, Dan (HP Labs Fort Collins)
2006-01-20 22:17 ` Muli Ben-Yehuda
2006-01-22 22:45 Magenheimer, Dan (HP Labs Fort Collins)
2006-01-24 23:42 Ian Pratt
2006-01-25 0:02 Magenheimer, Dan (HP Labs Fort Collins)
2006-01-25 0:16 ` Muli Ben-Yehuda
2006-01-25 1:35 Ian Pratt
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