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From: William Lee Irwin III <wli@holomorphy.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Andrea Arcangeli <andrea@suse.de>,
	linux-kernel@vger.kernel.org, torvalds@osdl.org
Subject: Re: can device drivers return non-ram via vm_ops->nopage?
Date: Sat, 20 Mar 2004 12:50:53 -0800	[thread overview]
Message-ID: <20040320205053.GJ2045@holomorphy.com> (raw)
In-Reply-To: <20040320121345.2a80e6a0.akpm@osdl.org>

On Sat, Mar 20, 2004 at 12:13:45PM -0800, Andrew Morton wrote:
> I agree that ->nopage implementations should not be doing what that driver
> is doing.  ->nopage is defined to return a page*: it's crazy to be
> returning someting from there which isn't covered by mem_map[].
> I just don't think it's important enough to be able to cope with
> non-mem_map[] "memory" in do_no_page(), so I agree that requiring ->mmap()
> to synchronously instantiate the pte's and retaining the debug check in
> do_no_page() is a good idea.

There are other reasons for doing it, e.g. unusual TLB attributes
and/or unusual pagetable structures backing the virtual region. I don't
see anyone standing up and screaming for more functionality than cache
coherency and/or disablement now, so as far as I'm concerned,
remap_area_pages() (or rmk's stuff) kills the issue.


-- wli

  parent reply	other threads:[~2004-03-20 20:51 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-20 13:30 can device drivers return non-ram via vm_ops->nopage? Andrea Arcangeli
2004-03-20 14:40 ` William Lee Irwin III
2004-03-20 15:06   ` Andrea Arcangeli
2004-03-20 15:27     ` William Lee Irwin III
2004-03-20 15:44     ` Russell King
2004-03-20 15:57       ` Andrea Arcangeli
2004-03-20 16:15         ` Russell King
2004-03-20 16:25           ` Andrea Arcangeli
2004-03-20 16:57             ` William Lee Irwin III
2004-03-20 17:48             ` Andrea Arcangeli
2004-03-20 19:03               ` Andrea Arcangeli
2004-03-20 15:58       ` Jaroslav Kysela
2004-03-20 16:09         ` Russell King
2004-03-20 19:44           ` Jaroslav Kysela
2004-03-20 22:23             ` Russell King
2004-03-20 22:45               ` William Lee Irwin III
2004-03-20 23:54                 ` Russell King
2004-03-21  0:22                   ` Zwane Mwaikambo
2004-03-22  4:46                     ` Benjamin Herrenschmidt
2004-03-22 18:23                       ` Richard Curnow
2004-03-21  0:23                   ` William Lee Irwin III
2004-03-21  9:52                   ` Arjan van de Ven
2004-03-21 10:39                   ` Jaroslav Kysela
2004-03-22  4:43             ` Benjamin Herrenschmidt
2004-03-20 20:13     ` Andrew Morton
2004-03-20 20:28       ` Andrea Arcangeli
2004-03-20 20:50       ` William Lee Irwin III [this message]
2004-03-20 22:26         ` Russell King
2004-03-20 22:45           ` William Lee Irwin III
2004-03-21 20:45             ` David Woodhouse
2004-03-21 20:49               ` Christoph Hellwig
2004-03-21 20:57                 ` David Woodhouse
2004-03-21 21:53                   ` Linus Torvalds
2004-03-21 22:17                     ` Jeff Garzik
2004-03-21 22:23                     ` David Woodhouse
2004-03-21 22:23                     ` Russell King
2004-03-21 22:34                       ` Jeff Garzik
2004-03-21 22:42                         ` David Woodhouse
2004-03-21 23:06                           ` Jeff Garzik
2004-03-21 22:51                         ` Russell King
2004-03-21 23:09                           ` Jeff Garzik
2004-03-21 23:11                           ` Linus Torvalds
2004-03-21 23:22                             ` Jeff Garzik
2004-03-21 23:51                               ` Linus Torvalds
2004-03-21 23:58                                 ` Russell King
2004-03-22  0:34                                   ` Andrea Arcangeli
2004-03-22  3:05                                     ` Linus Torvalds
2004-03-23 17:59                                   ` Andy Whitcroft
2004-03-23 17:58                                     ` David Woodhouse
2004-03-23 18:11                                     ` William Lee Irwin III
2004-03-22  0:02                                 ` David Woodhouse
2004-03-22  3:28                                   ` Linus Torvalds
2004-03-22  0:10                                 ` Jeff Garzik
2004-03-22  0:20                                   ` Russell King
2004-03-22  0:33                                     ` Jeff Garzik
2004-03-22  4:57                                     ` Benjamin Herrenschmidt
2004-03-21 23:45                             ` Russell King
2004-03-22  0:23                               ` William Lee Irwin III
2004-03-22  0:29                                 ` Jeff Garzik
2004-03-22  1:28                                   ` William Lee Irwin III
2004-03-22  6:36           ` William Lee Irwin III
2004-03-20 17:39 ` Linus Torvalds
2004-03-20 17:56   ` Andrea Arcangeli
2004-03-20 18:22   ` William Lee Irwin III
2004-03-21  3:13   ` Chris Wedgwood
2004-03-21  6:23     ` Christoph Hellwig
2004-03-21  7:00       ` Chris Wedgwood

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