From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: dhylands@gmail.com, guinan@bluebutton.com, linux-kernel@vger.kernel.org
Subject: Re: get_user_pages() cache issues on ARM
Date: Sat, 30 Sep 2006 18:05:48 +0100 [thread overview]
Message-ID: <20060930170548.GA24949@flint.arm.linux.org.uk> (raw)
In-Reply-To: <E1GTiBq-0002i3-00@dorka.pomaz.szeredi.hu>
On Sat, Sep 30, 2006 at 06:59:50PM +0200, Miklos Szeredi wrote:
> Hi Russell,
>
> The get_user_pages() vs dcache coherency issue still seems to be
> unresolved on ARM.
>
> See flush_anon_page() and flush_kernel_dcache_page() in
> Documentation/cachetlb.txt and their implementation on PARISC.
>
> Can you please take a look at this?
I'm sorry, I don't think I have sufficient understanding of the Linux VM
to look at these issues anymore.
The questions I have are:
- where do these pages that get_user_pages() finds and calls flush_anon_page()
on come from?
- why is the current ARM flush_dcache_page() (which is also called after
flush_anon_page()) not sufficient?
- if we implement flush_anon_page() does that mean that we end up flushing
multiple times in some circumstances? If so, how do we avoid this?
I'm really serious - I no longer understand the Linux VM sufficiently to
get this stuff right.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
next prev parent reply other threads:[~2006-09-30 17:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-30 16:59 get_user_pages() cache issues on ARM Miklos Szeredi
2006-09-30 17:05 ` Russell King [this message]
2006-09-30 17:18 ` Miklos Szeredi
2006-10-07 13:13 ` James Bottomley
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