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From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Linus Torvalds <torvalds@osdl.org>
Cc: David Miller <davem@davemloft.net>,
	nickpiggin@yahoo.com.au, ralf@linux-mips.org,
	Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	anemo@mba.ocn.ne.jp, linux-arch@vger.kernel.org,
	Martin Schwidefsky <schwidefsky@de.ibm.com>
Subject: Re: [PATCH 1/3] Fix COW D-cache aliasing on fork
Date: Fri, 20 Oct 2006 22:28:05 +0100	[thread overview]
Message-ID: <20061020212805.GG8894@flint.arm.linux.org.uk> (raw)
In-Reply-To: <Pine.LNX.4.64.0610201408070.3962@g5.osdl.org>

On Fri, Oct 20, 2006 at 02:12:11PM -0700, Linus Torvalds wrote:
> On Fri, 20 Oct 2006, Russell King wrote:
> > Well, looking at do_wp_page() I'm now quite concerned about ARM and COW.
> > I can't see how this code could _possibly_ work with a virtually indexed
> > cache as it stands.  Yet, the kernel does appear to work.
> 
> It really shouldn't need any extra code, exactly because by the time it 
> hits any page-fault, the caches had better be in sync with the physical 
> page contents _anyway_ (yes, being virtual, the caches will _duplicate_ 
> the contents, but since the pages are read-only, that aliasing should be 
> perfectly fine).

Oh, of course!  That explains why it actually works as expected!  Thanks
for filling back in that bit of swapped-out-years-ago-and-lost information.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

  reply	other threads:[~2006-10-20 21:28 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-19 16:35 [PATCH 1/3] Fix COW D-cache aliasing on fork Ralf Baechle
2006-10-19 16:35 ` [PATCH 2/3] Pass vma argument to copy_user_highpage() Ralf Baechle
2006-10-19 16:35 ` [PATCH 3/3] MIPS: Fix COW D-cache aliasing on fork Ralf Baechle
2006-10-22  2:32   ` Ralf Baechle
2006-10-19 17:46 ` [PATCH 1/3] " Nick Piggin
2006-10-19 18:13   ` Ralf Baechle
2006-10-19 18:48     ` Nick Piggin
2006-10-19 22:59     ` David Miller
2006-10-20 14:39       ` Nick Piggin
2006-10-20 15:49         ` Linus Torvalds
2006-10-20 15:57           ` Nick Piggin
2006-10-20 16:36             ` Linus Torvalds
2006-10-20 16:47               ` Nick Piggin
2006-10-20 17:16                 ` Linus Torvalds
2006-10-20 17:37                   ` Nick Piggin
2006-10-21  0:46                 ` Ralf Baechle
2006-10-20 19:36           ` David Miller
2006-10-20 19:54             ` Linus Torvalds
2006-10-20 19:58               ` David Miller
2006-10-20 20:10                 ` Linus Torvalds
2006-10-20 20:59                   ` Russell King
2006-10-20 21:06                     ` David Miller
2006-10-20 21:17                       ` Russell King
2006-10-20 21:30                         ` David Miller
2006-10-20 21:12                     ` Linus Torvalds
2006-10-20 21:28                       ` Russell King [this message]
2006-10-20 21:41                       ` Ralf Baechle
2006-10-21 16:28                         ` Atsushi Nemoto
2006-10-20 21:49                   ` Ralf Baechle
2006-10-20 22:02                     ` Linus Torvalds
2006-10-20 22:22                       ` David Miller
2006-10-20 22:51                         ` Ralf Baechle
2006-10-20 23:28                           ` Linus Torvalds
2006-10-21  0:06                             ` Ralf Baechle
2006-10-21  0:38                               ` Linus Torvalds
2006-10-21  1:29                                 ` Paul Mackerras
2006-10-21  2:11                                 ` David Miller
2006-10-21  2:37                                   ` Linus Torvalds
2006-10-21  2:46                                     ` David Miller
2006-10-21 18:27                                     ` Ralf Baechle
2006-10-22  1:34                                     ` Ralf Baechle
2006-12-02  9:49                                 ` Russell King
2006-10-23  8:50                   ` Martin Schwidefsky
2006-10-20 16:05         ` Ralf Baechle
2006-10-20 16:30           ` Nick Piggin
2006-10-20 19:23         ` David Miller

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