From: David Howells <dhowells@redhat.com>
To: Matt Mackall <mpm@selenic.com>
Cc: torvalds@osdl.org, akpm@osdl.org, davidm@snapgear.com,
linux-kernel@vger.kernel.org, uclinux-dev@uclinux.org
Subject: Re: [PATCH 17/20] FRV: Better mmap support in uClinux
Date: Fri, 19 Nov 2004 16:26:43 +0000 [thread overview]
Message-ID: <13104.1100881603@redhat.com> (raw)
In-Reply-To: <20041119052936.GE8040@waste.org>
> > (3) Files (and blockdevs) cannot be mapped shared since it is not
> > really possible to honour this by writing any changes back to the
> > backing device.
>
> [way behind on email]
>
> I think this could be done at msync, munmap and exit time? You end up
> flushing the entire mapping, but it's still correct (and POSIX
> compliant).
Don't forget write() too. If someone does a write, that would have to be
written over the mapping too. Obviously this is not impossible.
> And, if you wanted to be really clever, you could store a hash of each
> page to detect changes and avoid the extra I/O.
It'd probably have to be something like an md5 sum.
Okay, technically, we could probably emulate it, but is it worth it? I think
it's something to bear in mind for another time.
More to the point, perhaps, is making shared memory stuff work.
David
next prev parent reply other threads:[~2004-11-19 16:27 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20040401020550.GG3150@beast>
[not found] ` <76b4a884-2c3c-11d9-91a1-0002b3163499@redhat.com>
2004-11-01 19:30 ` [PATCH 3/14] FRV: Fujitsu FR-V arch documentation dhowells
2004-11-01 19:30 ` [PATCH 4/14] FRV: Bitops fixes dhowells
2004-11-02 8:19 ` Andrew Morton
2004-11-01 19:30 ` [PATCH 7/14] FRV: GDB stub dependent additional BUG()'s dhowells
2004-11-02 9:34 ` Christoph Hellwig
2004-11-02 16:09 ` David Howells
2004-11-03 10:39 ` Christoph Hellwig
2004-11-03 13:41 ` David Howells
2004-11-01 19:30 ` [PATCH 9/14] FRV: CONFIG_MMU fixes dhowells
2004-11-02 9:43 ` Christoph Hellwig
2004-11-03 15:06 ` David Howells
2004-11-03 15:13 ` Christoph Hellwig
2004-11-03 15:30 ` David Howells
2004-11-01 19:30 ` [PATCH 11/14] FRV: Add FDPIC ELF binary format driver dhowells
2004-11-02 8:18 ` Andrew Morton
2004-11-02 11:07 ` Andrew Morton
2004-11-02 16:47 ` David Howells
2004-11-02 17:23 ` Andi Kleen
2004-11-01 19:30 ` [PATCH 5/14] FRV: Fork fixes dhowells
2004-11-01 19:30 ` [PATCH 8/14] FRV: GP-REL data support dhowells
2004-11-02 8:18 ` Andrew Morton
2004-11-02 9:48 ` Christoph Hellwig
2004-11-02 16:34 ` David Howells
2004-11-03 10:42 ` Christoph Hellwig
2004-11-01 19:30 ` [PATCH 6/14] FRV: IDE fixes dhowells
2004-11-01 22:53 ` Alan Cox
2004-11-02 0:13 ` Bartlomiej Zolnierkiewicz
2004-11-02 10:57 ` David Howells
2004-11-01 19:30 ` [PATCH 10/14] FRV: Make calibrate_delay() optional dhowells
2004-11-02 0:06 ` john stultz
2004-11-02 11:01 ` David Howells
2004-11-02 8:17 ` Andrew Morton
2004-11-02 9:36 ` Christoph Hellwig
2004-11-02 16:29 ` David Howells
2004-11-03 10:40 ` Christoph Hellwig
2004-11-01 19:30 ` [PATCH 12/14] FRV: Generate more useful debug info dhowells
2004-11-02 0:29 ` Andrew Morton
2004-11-02 11:21 ` David Howells
2004-11-03 1:48 ` Linus Torvalds
2004-11-03 1:52 ` Linus Torvalds
2004-11-03 13:38 ` David Howells
2004-11-03 15:32 ` Linus Torvalds
2004-11-03 20:40 ` Florian Weimer
2004-11-03 20:42 ` Linus Torvalds
2004-11-12 14:57 ` Daniel Jacobowitz
2004-11-12 15:15 ` David Howells
2004-11-12 15:20 ` Daniel Jacobowitz
2004-11-01 19:30 ` [PATCH 14/14] FRV: Better mmap support in uClinux dhowells
2004-11-02 9:54 ` Christoph Hellwig
2004-11-02 16:43 ` David Howells
2004-11-03 10:45 ` Christoph Hellwig
2004-11-01 19:30 ` [PATCH 13/14] FRV: Convert extern inline -> static inline dhowells
2004-11-02 0:21 ` [PATCH 1/14] FRV: Fujitsu FR-V CPU arch implementation Andrew Morton
2004-11-04 11:54 ` David Howells
[not found] ` <200411011930.iA1JUKFH023161@warthog.cambridge.redhat.com>
2004-11-02 23:24 ` [uClinux-dev] [PATCH 2/14] FRV: Fujitsu FR-V arch include files Christoph Hellwig
2004-11-03 17:26 ` David Howells
2004-11-02 23:46 ` [uClinux-dev] [PATCH 1/14] FRV: Fujitsu FR-V CPU arch implementation Christoph Hellwig
2004-11-03 19:46 ` David Howells
2004-11-03 20:32 ` Christoph Hellwig
2004-11-08 14:34 ` [PATCH 1/20] FRV: Fujitsu FR-V CPU arch maintainer record dhowells
2004-11-08 14:34 ` [PATCH 2/20] FRV: Fujitsu FR-V arch documentation dhowells
2004-11-08 14:34 ` [PATCH 3/20] FRV: Fujitsu FR-V CPU arch implementation part 1 dhowells
2004-11-08 14:34 ` [PATCH 4/20] FRV: Fujitsu FR-V CPU arch implementation part 2 dhowells
2004-11-08 14:34 ` [PATCH 7/20] FRV: Fujitsu FR-V CPU arch implementation part 5 dhowells
2004-11-09 15:09 ` Geert Uytterhoeven
2004-11-08 14:34 ` [PATCH 6/20] FRV: Fujitsu FR-V CPU arch implementation part 4 dhowells
2004-11-08 14:34 ` [PATCH 5/20] FRV: Fujitsu FR-V CPU arch implementation part 3 dhowells
2004-11-08 14:34 ` [PATCH 9/20] FRV: Fujitsu FR-V CPU arch implementation part 7 dhowells
2004-11-08 14:34 ` [PATCH 11/20] FRV: Fujitsu FR-V CPU arch implementation part 9 dhowells
2004-11-08 14:34 ` [PATCH 10/20] FRV: Fujitsu FR-V CPU arch implementation part 8 dhowells
2004-11-08 14:34 ` [PATCH 8/20] FRV: Fujitsu FR-V CPU arch implementation part 6 dhowells
2004-11-08 14:34 ` [PATCH 16/20] FRV: Make calibrate_delay() optional dhowells
2004-11-08 14:34 ` [PATCH 15/20] FRV: Fujitsu FR-V arch include files dhowells
2004-11-08 14:34 ` [PATCH 14/20] " dhowells
2004-11-08 14:34 ` [PATCH 13/20] " dhowells
2004-11-08 14:34 ` [PATCH 18/20] FRV: procfs changes for nommu changes dhowells
2004-11-08 14:34 ` [PATCH 19/20] FRV: change setup_arg_pages() to take stack pointer dhowells
2004-11-08 14:34 ` [PATCH 17/20] FRV: Better mmap support in uClinux dhowells
2004-11-09 12:57 ` Christoph Hellwig
2004-11-09 13:55 ` David Howells
2004-11-09 14:02 ` Christoph Hellwig
2004-11-19 5:29 ` Matt Mackall
2004-11-19 16:26 ` David Howells [this message]
2004-11-19 16:56 ` Matt Mackall
2004-11-19 17:06 ` David Howells
2004-11-19 17:42 ` Linus Torvalds
2004-11-08 14:34 ` [PATCH 20/20] FRV: Add FDPIC ELF binary format driver dhowells
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