From: "Imran Badr" <imran.badr@cavium.com>
To: "'Ralf Baechle'" <ralf@linux-mips.org>,
"'Alan Cox'" <alan@lxorguk.ukuu.org.uk>
Cc: <linux-kernel@vger.kernel.org>
Subject: RE: Cache coherency and snooping
Date: Tue, 13 Aug 2002 17:19:56 -0700 [thread overview]
Message-ID: <0a9c01c24328$5205f470$9e10a8c0@IMRANPC> (raw)
In-Reply-To: <20020814020825.A11382@linux-mips.org>
Thanks Ralf and Alan,
What if I allocate memory at boot-time using alloc_bootmem*(..)?
Imran.
-----Original Message-----
From: Ralf Baechle [mailto:ralf@linux-mips.org]
Sent: Tuesday, August 13, 2002 5:08 PM
To: Imran Badr
Cc: linux-kernel@vger.kernel.org
Subject: Re: Cache coherency and snooping
On Tue, Aug 13, 2002 at 04:22:31PM -0700, Imran Badr wrote:
> How can I define a certain region of memory so that it is never cached? I
> want to use non-cached region of memory to communicate to my PCI device to
> avoid system overhead in cache snooping.
On every sane platform the hardware performs better at keeping the
coherency than software ever could. Don't even think about it unless
you for some reason absolutely must disable caching. Aside and as Alan
already mentioned the allocation of uncached memory isn't supported.
Ralf
next prev parent reply other threads:[~2002-08-14 0:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-13 22:57 patch 04/38: SUNRPC: support for GSSD client Kendrick M. Smith
2002-08-13 22:57 ` Kendrick M. Smith
2002-08-13 23:22 ` Cache coherency and snooping Imran Badr
2002-08-13 23:38 ` Alan Cox
2002-08-14 0:08 ` Ralf Baechle
2002-08-14 0:19 ` Imran Badr [this message]
2002-08-14 0:29 ` Ralf Baechle
2002-08-14 1:00 ` Imran Badr
2002-08-14 1:38 ` Rik van Riel
2002-08-14 1:56 ` Imran Badr
2002-08-14 8:16 ` Ralf Baechle
2002-08-14 9:00 ` David S. Miller
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