From: Gilad Ben-Yossef <gilad@benyossef.com>
To: Bhavana Nagendra <Bhavana.Nagendra@3dlabs.com>
Cc: Mike Galbraith <efault@gmx.de>, linux-kernel@vger.kernel.org
Subject: RE: Alloc and lock down large amounts of memory
Date: 21 Aug 2002 08:29:52 +0300 [thread overview]
Message-ID: <1029907792.19202.25.camel@gby.benyossef.com> (raw)
In-Reply-To: <23B25974812ED411B48200D0B774071701248C6A@exchusa03.intense3d.com>
On Tue, 2002-08-20 at 23:08, Bhavana Nagendra wrote:
> >
> > Curiosity: why do you want to do device DMA buffer
> > allocation from userland?
>
> Gilad, I looked at mm/memory.c and map_user_kiobuf() lets me
> map user memory into kernel memory and pins it down. A scatter
> gatter mapping (say, pci_map_sg()) will create a seemingly
> contiguous buffer for DMA purposes. Does that sound right to you?
Can your device actually use scatter gather (has 'virtual bus addresses'
or can get the buffer in several chunks?) Can the device actually DMA
all the memory in the system?
In short, I have no idea. :-)
Gilad.
--
Gilad Ben-Yossef <gilad@benyossef.com>
http://benyossef.com
"Money talks, bullshit walks and GNU awks."
-- Shachar "Sun" Shemesh, debt collector for the GNU/Yakuza
next prev parent reply other threads:[~2002-08-21 5:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-20 20:08 Bhavana Nagendra
2002-08-20 20:47 ` Richard B. Johnson
[not found] ` <Pine.LNX.3.95.1020820163301.27264A-100000@chaos.analogic.c om>
2002-08-21 4:43 ` Mike Galbraith
2002-08-21 5:29 ` Gilad Ben-Yossef [this message]
[not found] <23B25974812ED411B48200D0B774071701248C6A@exchusa03.intense 3d.com>
2002-08-21 4:31 ` Mike Galbraith
2002-08-21 13:29 ` Roland Kuhn
2002-08-21 14:35 ` Mike Galbraith
-- strict thread matches above, loose matches on Subject: below --
2002-08-20 14:51 Bhavana Nagendra
2002-08-21 5:27 ` Gilad Ben-Yossef
2002-08-16 14:38 Bhavana Nagendra
2002-08-18 12:09 ` Gilad Ben-Yossef
2002-08-18 12:18 ` Alan Cox
2002-08-18 22:45 ` Gilad Ben-Yossef
2002-08-18 12:19 ` Gilad Ben-Yossef
2002-08-19 12:06 ` Bhavana Nagendra
2002-08-20 5:38 ` Gilad Ben-Yossef
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