From: Eugene Surovegin <ebs@ebshome.net>
To: Shawn Jin <shawnxjin@gmail.com>
Cc: ppcembed <linuxppc-embedded@ozlabs.org>
Subject: Re: DMA consistent allocation is limited to 2MB on 2.6.11 for ppc440?
Date: Wed, 18 May 2005 18:24:04 -0700 [thread overview]
Message-ID: <20050519012404.GA11587@gate.ebshome.net> (raw)
In-Reply-To: <c3d0340b050518175411c484e3@mail.gmail.com>
On Wed, May 18, 2005 at 05:54:39PM -0700, Shawn Jin wrote:
> The page table 'consistent_pte' covers the uncached DMA consistent
> allocation space. Its size is only one page, each page has 512 PTEs.
> That means only 2MB memory are available for DMA. For some
> applications this is not enough. So how to eliminate this limitation?
No, _all_ physical memory is available for DMA. "consistent" pool is
used for small non-cached allocations, e.g. buffer descriptors, etc.
Don't use it for actual data buffers.
--
Eugene
next prev parent reply other threads:[~2005-05-19 1:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-19 0:54 DMA consistent allocation is limited to 2MB on 2.6.11 for ppc440? Shawn Jin
2005-05-19 1:24 ` Eugene Surovegin [this message]
2005-05-19 1:52 ` Shawn Jin
2005-05-19 2:09 ` Eugene Surovegin
2005-05-20 18:12 ` Shawn Jin
2005-05-20 20:16 ` Matt Porter
2005-05-20 23:51 ` Shawn Jin
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