From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: James Bottomley <James.Bottomley@steeleye.com>
Cc: Russell King <rmk@arm.linux.org.uk>,
William Lee Irwin III <wli@holomorphy.com>,
Linux Arch list <linux-arch@vger.kernel.org>,
Jeff Garzik <jgarzik@pobox.com>,
Linus Torvalds <torvalds@osdl.org>,
David Woodhouse <dwmw2@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
Andrew Morton <akpm@osdl.org>, Andrea Arcangeli <andrea@suse.de>
Subject: Re: can device drivers return non-ram via vm_ops->nopage?
Date: Tue, 23 Mar 2004 08:50:30 +1100 [thread overview]
Message-ID: <1079992229.22190.29.camel@gaston> (raw)
In-Reply-To: <1079969221.1759.25.camel@mulgrave>
> I could see a point: since we can only keep one address space coherent,
> we cannot allow multiple mmappings of the same region. Thus, processes
> would be able to hand off the coherent mmap, but wouldn't be allowed
> simultaneously to map. the unmap API would be telling the arch that the
> mapping was free to be remapped.
You cannot have the mapping coherent in both kernel and user space ? Hrm,
I'm afraid drivers won't like that. The DRI will definitely be unhappy,
and while I don't think sound drivers need to tap the buffers from the
kernel mapping in normal cases, I'm pretty sure things like infiniband
or myrinet will have a problem too.
Ben.
next prev parent reply other threads:[~2004-03-22 22:07 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20040321204931.A11519@infradead.org>
[not found] ` <1079902670.17681.324.camel@imladris.demon.co.uk>
[not found] ` <Pine.LNX.4.58.0403211349340.1106@ppc970.osdl.org>
[not found] ` <20040321222327.D26708@flint.arm.linux.org.uk>
[not found] ` <405E1859.5030906@pobox.com>
[not found] ` <20040321225117.F26708@flint.arm.linux.org.uk>
[not found] ` <Pine.LNX.4.58.0403211504550.1106@ppc970.osdl.org>
[not found] ` <20040321234515.G26708@flint.arm.linux.org.uk>
[not found] ` <20040322002349.GZ2045@holomorphy.com>
[not found] ` <405E3387.1050505@pobox.com>
2004-03-22 3:45 ` can device drivers return non-ram via vm_ops->nopage? William Lee Irwin III
2004-03-22 4:41 ` James Bottomley
2004-03-22 4:46 ` William Lee Irwin III
2004-03-22 4:56 ` James Bottomley
2004-03-22 5:26 ` Benjamin Herrenschmidt
2004-03-22 11:58 ` Andrea Arcangeli
2004-03-22 12:05 ` Russell King
2004-03-22 12:34 ` Andrea Arcangeli
2004-03-22 9:30 ` Russell King
2004-03-22 15:04 ` James Bottomley
2004-03-22 15:15 ` Russell King
2004-03-22 15:27 ` James Bottomley
2004-03-22 21:50 ` Benjamin Herrenschmidt [this message]
2004-03-22 22:18 ` Jeff Garzik
2004-03-22 22:35 ` William Lee Irwin III
2004-03-22 23:57 ` Benjamin Herrenschmidt
2004-03-23 0:22 ` David Woodhouse
2004-03-23 2:07 ` William Lee Irwin III
2004-03-23 9:28 ` Russell King
2004-03-23 9:34 ` David Woodhouse
2004-03-23 10:04 ` Russell King
2004-03-23 10:05 ` William Lee Irwin III
2004-03-23 11:29 ` Benjamin Herrenschmidt
2004-03-23 11:35 ` Andrea Arcangeli
2004-03-23 11:44 ` William Lee Irwin III
2004-03-23 12:34 ` Andrea Arcangeli
2004-03-23 12:40 ` Russell King
2004-03-23 15:25 ` Linus Torvalds
2004-03-23 15:36 ` Andrea Arcangeli
2004-03-23 15:46 ` Linus Torvalds
2004-03-23 15:50 ` Russell King
2004-03-23 22:10 ` Benjamin Herrenschmidt
2004-03-25 20:25 ` Russell King
2004-03-28 10:17 ` Russell King
2004-03-23 12:49 ` William Lee Irwin III
2004-03-22 23:19 ` Russell King
2004-03-22 23:35 ` Jeff Garzik
2004-03-23 2:26 ` James Bottomley
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