From: Andi Kleen <ak@muc.de>
To: hpa@zytor.com (H. Peter Anvin)
Cc: linux-kernel@vger.kernel.org
Subject: Re: chasing the four level page table
Date: Sat, 15 Jan 2005 05:24:54 +0100 [thread overview]
Message-ID: <m1brbrwc89.fsf@muc.de> (raw)
In-Reply-To: <csa0kn$4eg$1@terminus.zytor.com> (H. Peter Anvin's message of "Sat, 15 Jan 2005 02:54:15 +0000 (UTC)")
hpa@zytor.com (H. Peter Anvin) writes:
>
> There seems to be at least two classes of device drivers -- graphics
> and RDMA -- which have a genuine need to DMA user pages, after
> appropriate locking, of course.
And block devices with O_DIRECT and network devices. We supported that
fine for years with get_user_pages.
The issue with DRM is just that it does something more different:
it wants to get at a AGP page outside get_user_pages doesn't work for
this because the AGP hole is often outside mem_map. For that a
nice helper is missing.
I'm not 100% we really want a helper because it's rather obscure
requirement, unlikely to be useful for others, and it may be better
to keep it in DRM.
-Andi
next prev parent reply other threads:[~2005-01-15 4:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-06 17:17 chasing the four level page table Jon Smirl
2005-01-06 18:12 ` Andi Kleen
2005-01-06 18:36 ` Jon Smirl
2005-01-06 19:38 ` Andi Kleen
2005-01-06 20:05 ` Jon Smirl
2005-01-06 21:41 ` Dave Jones
2005-01-08 5:22 ` Jon Smirl
2005-01-15 2:54 ` H. Peter Anvin
2005-01-15 3:37 ` Roland Dreier
2005-01-15 4:24 ` Andi Kleen [this message]
2005-01-15 5:59 ` Jon Smirl
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