From: NIIBE Yutaka <gniibe@m17n.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: rmk@arm.linux.org.uk (Russell King),
marcelo@conectiva.com.br (Marcelo Tosatti),
torvalds@transmeta.com (Linus Torvalds),
linux-kernel@vger.kernel.org (lkml)
Subject: Re: [PATCH] swapin flush cache bug
Date: Wed, 14 Feb 2001 11:08:07 +0900 (JST) [thread overview]
Message-ID: <200102140208.LAA18226@mule.m17n.org> (raw)
In-Reply-To: <E14Sdb6-0001V5-00@the-village.bc.nu>
In-Reply-To: <200102131053.TAA11808@mule.m17n.org> <E14Sdb6-0001V5-00@the-village.bc.nu>
Alan Cox wrote:
> Ok we need to handle that case a bit more intelligently so those flushes dont
> get into other ports code paths.
Possibly at fs/buffer.c:end_buffer_io_async?
We need to flush the cache when I/O was READ or READA. Is there any
way for end_buffer_io_async to distinguish which I/O (READ or WRITE)
has been done?
--------------------------------------
Problem with write-back cache.
(1) Page got swapped out
Swap out
[ Disk ] <---- P [ Page ]
(2) Page got swapped in asynchronously, possibly by read-ahead
Swap in
[ Disk ] ----> P [ Page ]
K
The I/O from disk goes through kernel virtual address K.
We have cache entries indexed by K.
(3) Page fault occurs at user space U
[ Disk ] P [ Page ] <----- U
K
The control goes to do_swap_page, found the page at
lookup_swap_cache.
If K and U indexes differently, we have cache alias issues,
we need to flush the entries indexed by K.
--
next prev parent reply other threads:[~2001-02-14 2:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-02-12 23:21 [PATCH] swapin flush cache bug Marcelo Tosatti
2001-02-13 9:50 ` Russell King
2001-02-13 10:53 ` NIIBE Yutaka
2001-02-13 11:16 ` Russell King
2001-02-13 11:26 ` Alan Cox
2001-02-13 23:50 ` NIIBE Yutaka
2001-02-14 2:08 ` NIIBE Yutaka [this message]
2001-02-14 10:12 ` Marcelo Tosatti
2001-06-27 0:51 ` NIIBE Yutaka
2001-06-27 10:11 ` Marcelo Tosatti
2001-06-28 0:42 ` David S. Miller
2001-06-28 0:07 ` NIIBE Yutaka
2001-06-27 22:41 ` Marcelo Tosatti
2001-06-28 0:23 ` Stephen C. Tweedie
2001-06-28 0:47 ` David S. Miller
2001-06-28 1:10 ` David S. Miller
2001-06-29 14:18 ` NIIBE Yutaka
2001-07-02 22:47 ` Cache issues David S. Miller
2001-06-28 0:41 ` [PATCH] swapin flush cache bug NIIBE Yutaka
2001-06-28 1:04 ` NIIBE Yutaka
2001-07-02 11:23 ` Cache issues NIIBE Yutaka
2001-07-03 0:04 ` NIIBE Yutaka
2001-06-28 0:46 ` [PATCH] swapin flush cache bug David S. Miller
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