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Subject: Re: ZERO_PAGE() vs. loadable modules in Redhat 4.4 i386 kernels ...
From: Arjan van de Ven <arjan@infradead.org>
To: Casey Leedom <casey_leedom@yahoo.com>
Cc: linux-kernel@vger.kernel.org
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Organization: Intel International BV
Date: Wed, 27 Jun 2007 11:39:06 -0700
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On Wed, 2007-06-27 at 11:12 -0700, Casey Leedom wrote:
> Hello,
> 
>   I'm working on a driver that does a get_user_pages() for a DMA write.  We
> have a timeout on the DMA completion where we mark the pages as COW and return
> to the application so it can potentially generate more data in order to
> increase throughput, etc.  The problem is that when we traverse the
> PGT/PUD/PMD/PTE hierarchy to mark the pages, we sometime fault out when the PUD
> covering [0x80000000, 0xc0000000) comes out as zero when that entire region is
> covered by a single large malloc()'ed buffer.  

you forgot to attach your source code or provide a URL to it.....