From: Peter Horton <pdh@colonel-panic.org>
To: Jun Sun <jsun@mvista.com>
Cc: Bob Breuer <bbreuer@righthandtech.com>, linux-mips@linux-mips.org
Subject: Re: problems on D-cache alias in 2.4.22
Date: Tue, 18 May 2004 20:10:19 +0100 [thread overview]
Message-ID: <20040518191019.GA11007@skeleton-jack> (raw)
In-Reply-To: <20040518114519.C5390@mvista.com>
On Tue, May 18, 2004 at 11:45:19AM -0700, Jun Sun wrote:
>
> Like others suggested, this is not the right fix. flush_page_to_ram()
> is correctly nullified. Its job should be done somewhere else
> by other routines.
>
> Here are a couple of random ideas for finding the true root cause:
>
We know what the true root cause is :-)
IDE PIO fills the D-cache with the read data (write allocate) as it
copies it to the page cache.
The kernel maps the page cache page into user space ... BANG! possible
D-cache alias.
The kernel doesn't bother flushing the page cache page from the D-cache
as it's never accessed at it's page cache address.
The current fix in the Cobalt patches (2.4 & 2.6) just flushes the read
data out of the D-cache after every IDE insw()/insl(). This is the least
intrusive fix.
Some Sparc machines also see this problem.
P.
next prev parent reply other threads:[~2004-05-18 19:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-18 18:17 problems on D-cache alias in 2.4.22 Bob Breuer
2004-05-18 18:17 ` Bob Breuer
2004-05-18 18:45 ` Jun Sun
2004-05-18 19:10 ` Peter Horton [this message]
2004-05-18 19:50 ` Ralf Baechle
2004-05-18 18:24 ` Alan Cox
2004-05-18 21:21 ` Peter Horton
2004-05-18 22:25 ` Jun Sun
2004-05-18 23:29 ` Peter Horton
2004-05-18 20:02 ` Ralf Baechle
2004-05-18 20:10 ` Thiemo Seufer
-- strict thread matches above, loose matches on Subject: below --
2004-05-13 22:05 Bob Breuer
2004-05-13 22:05 ` Bob Breuer
2004-05-14 2:59 ` wuming
2004-05-14 7:52 ` Peter Horton
2004-05-15 0:12 ` Ralf Baechle
2004-05-15 12:31 ` Fuxin Zhang
2004-05-13 6:52 wuming
2004-05-14 7:45 ` Peter Horton
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