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Date: Tue, 12 Nov 2002 12:49:50 -0200 (BRST)
From: Rik van Riel <riel@conectiva.com.br>
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To: "David S. Miller" <davem@redhat.com>
cc: hugh@veritas.com, <akpm@digeo.com>, <dmccr@us.ibm.com>,
       <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] flush_cache_page while pte valid 
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On Mon, 11 Nov 2002, David S. Miller wrote:
>    From: Hugh Dickins <hugh@veritas.com>
>    Date: Tue, 12 Nov 2002 06:53:04 +0000 (GMT)
>
>    Thanks for shedding light on that; but I'm still wondering if there
>    might be data loss if userspace modifies the page in the tiny window
>    between correctly positioned flush_cache_page and pte invalidation?
>
> The flush merely writes back the data, a copy-back operation, fully L2
> cache coherent.  All cpus will see correct data if an intermittant
> store occurs.

The CPUs will, but the harddisk might not.

We really need to get this right in the swapout path.

regards,

Rik
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