From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org,
Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Subject: Re: [PATCH 1/3] Fix COW D-cache aliasing on fork
Date: Fri, 20 Oct 2006 04:48:50 +1000 [thread overview]
Message-ID: <4537C892.4010000@yahoo.com.au> (raw)
In-Reply-To: <20061019181346.GA5421@linux-mips.org>
Ralf Baechle wrote:
> On Fri, Oct 20, 2006 at 03:46:35AM +1000, Nick Piggin wrote:
>
>
>>What about if you just flush the caches after write protecting all
>>COW pages? Would that work? Simpler? Better performance? (I don't know)
>
>
> That would require changing the order of cache flush and tlb flush. To
Can't we just move flush_cache_mm to below the copy_page_range, before
the flush_tlb_mm?
> keep certain architectures that require a valid translation in the TLB
> the cacheflush has to be done first. Not sure if those architectures need
> a writeable mapping for dirty cachelines - I think hypersparc was one
> of them.
If the cache is dirty, then the TLB must have a writeable mapping in it,
mustn't it? If there is an architecture where this isn't the case, then
the current code is broken anyway, because in your example the T2 thread
is dirtying data right before the mapping gets write protected anyway.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2006-10-19 18:48 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 [this message]
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
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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