From: David Woodhouse <dwmw2@infradead.org>
To: Roland Dreier <roland@topspin.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: PCI DMA to small buffers on cache-incoherent arch
Date: Tue, 11 Jun 2002 15:04:26 +0100 [thread overview]
Message-ID: <28713.1023804266@redhat.com> (raw)
In-Reply-To: <52y9dn86k5.fsf@topspin.com>
roland@topspin.com said:
> Replying to myself.... Anyway, I realized that even my idea above is
> wrong. I don't see _any_ safe way to share a cache line between a DMA
> buffer and other data. Access to the cache line might pull the cache
> line back in and write it back at any time, which could corrupt the
> DMA'ed data. I don't see a way to hide the existence of cache lines
> etc. from the driver.
Access to a cache line can't be shared safely. Disable the cache for that
page while its ownership is in doubt and you can happily share the RAM
though. If we find another CPU which fetches cache lines preemptively, we
may have to do that anyway.
--
dwmw2
next prev parent reply other threads:[~2002-06-11 14:04 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-06-08 20:38 PCI DMA to small buffers on cache-incoherent arch Roland Dreier
2002-06-08 13:58 ` Anton Blanchard
2002-06-09 0:52 ` Roland Dreier
2002-06-08 23:03 ` David S. Miller
2002-06-09 0:40 ` Roland Dreier
2002-06-09 0:53 ` David S. Miller
2002-06-09 1:26 ` Roland Dreier
2002-06-09 5:29 ` David S. Miller
2002-06-09 6:16 ` Roland Dreier
2002-06-10 16:03 ` Roland Dreier
2002-06-11 14:04 ` David Woodhouse [this message]
2002-06-09 6:45 ` Oliver Neukum
2002-06-10 4:24 ` David S. Miller
2002-06-10 10:00 ` Oliver Neukum
2002-06-10 10:24 ` David S. Miller
2002-06-09 9:51 ` Paul Mackerras
2002-06-09 10:54 ` Benjamin Herrenschmidt
2002-06-10 4:27 ` David S. Miller
2002-06-10 15:59 ` Roland Dreier
2002-06-10 17:03 ` Tom Rini
2002-06-10 17:22 ` Oliver Neukum
2002-06-10 17:29 ` Tom Rini
2002-06-10 17:39 ` Oliver Neukum
2002-06-10 19:03 ` Roland Dreier
2002-06-10 19:14 ` Tom Rini
2002-06-10 19:21 ` Roland Dreier
2002-06-10 19:26 ` Tom Rini
2002-06-10 17:57 ` Russell King
2002-06-10 17:28 ` Roland Dreier
2002-06-10 18:07 ` William Jhun
2002-06-10 18:29 ` William Jhun
2002-06-10 18:33 ` Mark Zealey
2002-06-10 18:44 ` Oliver Neukum
2002-06-11 3:10 ` David S. Miller
2002-06-11 4:04 ` Roland Dreier
2002-06-11 4:16 ` Brad Hards
2002-06-11 4:24 ` Roland Dreier
2002-06-11 4:24 ` David S. Miller
2002-06-11 4:21 ` David S. Miller
2002-06-11 4:39 ` Roland Dreier
2002-06-11 4:38 ` David S. Miller
2002-06-11 6:23 ` Oliver Neukum
2002-06-11 6:38 ` David S. Miller
2002-06-11 7:38 ` Oliver Neukum
2002-06-11 7:36 ` David S. Miller
2002-06-11 7:43 ` David S. Miller
2002-06-11 8:07 ` Oliver Neukum
2002-06-11 8:15 ` David S. Miller
2002-06-11 12:06 ` Oliver Neukum
2002-06-11 12:04 ` David S. Miller
2002-06-11 14:23 ` Oliver Neukum
2002-06-14 4:14 ` David S. Miller
2002-06-11 18:26 ` Roland Dreier
2002-06-11 17:29 ` Benjamin Herrenschmidt
2002-06-12 12:02 ` Oliver Neukum
2002-06-11 20:06 ` Benjamin Herrenschmidt
2002-06-12 12:02 ` David S. Miller
2002-06-11 23:00 ` Thunder from the hill
2002-06-11 23:56 ` Roland Dreier
2002-06-12 0:09 ` Thunder from the hill
2002-06-11 15:57 ` William Jhun
2002-06-12 9:06 ` Pavel Machek
2002-06-12 20:16 ` David S. Miller
2002-06-12 11:47 ` David S. Miller
2002-06-12 12:08 ` Oliver Neukum
2002-06-14 4:41 ` David S. Miller
2002-06-12 16:09 ` William Jhun
2002-06-09 1:30 ` Albert D. Cahalan
2002-06-09 5:29 ` David S. Miller
2002-06-09 6:33 ` Albert D. Cahalan
2002-06-09 6:50 ` Oliver Neukum
2002-06-09 6:57 ` Albert D. Cahalan
2002-06-09 7:15 ` Oliver Neukum
2002-06-09 8:48 ` Russell King
2002-06-09 15:42 ` Albert D. Cahalan
2002-06-09 23:26 ` Oliver Neukum
-- strict thread matches above, loose matches on Subject: below --
2002-06-11 5:31 David Brownell
2002-06-11 5:44 ` David S. Miller
2002-06-11 15:12 ` David Brownell
2002-06-11 15:44 ` Oliver Neukum
2002-06-12 3:25 ` David S. Miller
2002-06-11 17:33 ` Benjamin Herrenschmidt
2002-06-12 9:42 ` David S. Miller
2002-06-12 14:14 ` David Brownell
2002-06-12 15:00 ` Benjamin Herrenschmidt
2002-06-12 18:44 ` Roland Dreier
2002-06-12 19:13 ` David Brownell
2002-06-12 19:58 ` Oliver Neukum
2002-06-12 22:51 ` David S. Miller
2002-06-12 23:17 ` Oliver Neukum
2002-06-13 4:57 ` David Brownell
2002-06-12 22:46 ` David S. Miller
2002-06-13 5:13 ` David Brownell
2002-06-13 9:38 ` David S. Miller
2002-06-12 22:50 ` David S. Miller
2002-06-12 6:25 ` David Brownell
2002-06-12 6:24 ` David S. Miller
2002-06-12 7:06 ` David Brownell
2002-06-12 9:22 ` David S. Miller
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