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From: "David S. Miller" <davem@redhat.com>
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Date: Wed, 27 Jun 2001 17:47:45 -0700 (PDT)
To: NIIBE Yutaka <gniibe@m17n.org>
Cc: "Stephen C. Tweedie" <sct@redhat.com>,
        Marcelo Tosatti <marcelo@conectiva.com.br>,
        lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] swapin flush cache bug
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NIIBE Yutaka writes:
 > (2) Page got swapped in asynchronously, possibly by read-ahead
 > 
 >            Swap in
 >    [ Page ] <---- [ Disk ]
 > 	   K
 > 
 >    The I/O from disk goes through kernel virtual address K.
 >    We have cache entries indexed by K.

The I/O completion must flush the cache, not the VM subsystem.

You must implement cache flushing at the DMA tranfer end point
to fix the problem you are describing.

Later,
David S. Miller
davem@redhat.com