From: "Franck Bui-Huu" <vagabon.xyz@gmail.com>
To: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: linux-fbdev-devel@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC 2.6.19 1/1] fbdev,mm: hecuba/E-Ink fbdev driver v2
Date: Wed, 13 Dec 2006 09:38:26 +0100 [thread overview]
Message-ID: <cda58cb80612130038x6b81a00dv813d10726d495eda@mail.gmail.com> (raw)
In-Reply-To: <45a44e480612111554j1450f35ub4d9932e5cd32d4@mail.gmail.com>
On 12/12/06, Jaya Kumar <jayakumar.lkml@gmail.com> wrote:
> I think that PTEs set up by vmalloc are marked cacheable and via the
> above nopage end up as cacheable. I'm not doing DMA. So the accesses
> are through the cache so I don't think cache aliasing is an issue for
> this case. Please let me know if I misunderstood.
>
This issue is not related to DMA: there are 2 different virtual
addresses that can map the same physical address. If these 2 virtual
addresses use 2 different data cache entries then you have a cache
aliasing issue. In your case the 2 different virtual addresses are (1)
the one got by the kernel (returned by vmalloc) (2) the one got by the
application (returned by mmap).
Hope that helps.
--
Franck
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next prev parent reply other threads:[~2006-12-13 8:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-11 10:46 jayakumar.lkml
2006-12-11 16:37 ` Franck Bui-Huu
2006-12-11 23:54 ` Jaya Kumar
2006-12-13 8:38 ` Franck Bui-Huu [this message]
2006-12-17 4:25 ` Jaya Kumar
2006-12-20 8:50 ` Franck Bui-Huu
2006-12-22 9:57 ` Franck Bui-Huu
2006-12-28 3:53 ` Jaya Kumar
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