From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Li Yang <leoli@freescale.com>
Cc: linuxppc-dev@ozlabs.org, paulus@samba.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/mm: setting mmaped page cache property through device tree
Date: Fri, 04 Dec 2009 13:37:37 +1100 [thread overview]
Message-ID: <1259894257.2076.1244.camel@pasglop> (raw)
In-Reply-To: <2a27d3730912010334q24bf0e06g84839aae131475ec@mail.gmail.com>
On Tue, 2009-12-01 at 19:34 +0800, Li Yang wrote:
> The scenario for the second case is to pre-allocate some memory to a
> certain application or device (probably through mem=XXX kernel
> parameter or limit through device tree). The memory is not known to
> kernel, but fully managed by the application/device. We need being
> able to map the region cachable for better performance.
>
> > trying to achieve here ? We can find a solution though it might
> involve
> > a specific driver to handle that memory.
>
> Right, but what the user to kernel API should be used? Is it ok to
> use the O_SYNC flag as I previously proposed?
If it's cachable, why don't you write yourself a little driver that
allocates memory maps it to userspace and provides you with the physical
addresses and problem solved ?
Cheers,
Ben.
prev parent reply other threads:[~2009-12-04 2:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-01 10:30 [PATCH] powerpc/mm: setting mmaped page cache property through device tree Li Yang
2009-12-01 10:58 ` Benjamin Herrenschmidt
2009-12-01 11:34 ` Li Yang
2009-12-01 14:35 ` Segher Boessenkool
2009-12-02 6:25 ` Li Yang
2009-12-03 4:15 ` Segher Boessenkool
2009-12-03 6:15 ` Li Yang
2009-12-04 2:38 ` Benjamin Herrenschmidt
2009-12-04 2:37 ` Benjamin Herrenschmidt [this message]
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