From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: <linux-kernel@vger.kernel.org>, <linux-xfs@oss.sgi.com>
Subject: Re: %u-order allocation failed
Date: Sun, 7 Oct 2001 13:12:02 +0200 [thread overview]
Message-ID: <20011007111202.17296@smtp.wanadoo.fr> (raw)
In-Reply-To: <Pine.LNX.3.96.1011007003227.18004B-100000@artax.karlin.mff.cuni.cz>
In-Reply-To: <Pine.LNX.3.96.1011007003227.18004B-100000@artax.karlin.mff.cuni.cz>
>
>You are right. Code that allocates more than page and expects it to be
>physicaly contignuous is broken by design. Even rewrite the driver or
>allocate memory on boot. It will be very hard to audit all drivers for it.
Well, the problem here is not code. Some piece of hardware just can't
scatter gather, or in some case, they can, but the scatter/gather list
itself has to be contiguous and can be larger than a page.
The fact that kmalloc returns physically contiguous memory is a feature
and can't be modified that easily. If you intend to do so, then you need
different GFP flags, for example a GFP_CONTIGUOUS flag, and then make
sure that drivers allocating DMA memory use that new flag.
Ben.
next prev parent reply other threads:[~2001-10-07 11:12 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-10-05 11:07 %u-order allocation failed Krzysztof Rusocki
2001-10-05 11:59 ` Rik van Riel
2001-10-05 20:18 ` Seth Mos
2001-10-05 20:22 ` Rik van Riel
2001-10-05 20:31 ` Seth Mos
2001-10-05 20:43 ` Steve Lord
2001-10-05 21:09 ` Seth Mos
2001-10-05 22:06 ` David Schwartz
2001-10-05 22:16 ` Seth Mos
2001-10-06 14:00 ` Mikulas Patocka
2001-10-06 14:03 ` Rik van Riel
2001-10-06 14:44 ` Mikulas Patocka
2001-10-06 15:31 ` Mikulas Patocka
2001-10-06 19:05 ` Mikulas Patocka
2001-10-06 16:58 ` Rik van Riel
2001-10-06 17:48 ` Mikulas Patocka
2001-10-06 18:12 ` Anton Blanchard
2001-10-06 19:07 ` Mikulas Patocka
2001-10-06 20:13 ` Benjamin Herrenschmidt
2001-10-06 22:34 ` Mikulas Patocka
2001-10-07 1:23 ` Rik van Riel
2001-10-07 11:12 ` Benjamin Herrenschmidt [this message]
2001-10-06 21:13 ` Alan Cox
2001-10-06 22:31 ` Mikulas Patocka
2001-10-06 22:42 ` Alan Cox
2001-10-06 22:58 ` Mikulas Patocka
[not found] ` <Pine.LNX.3.96.1011007003803.18004D-100000@artax.karlin.mff.cuni .cz>
2001-10-06 23:36 ` Alex Bligh - linux-kernel
[not found] ` <Pine.LNX.3.96.1011007002406.18004A-100000@artax.karlin.mff.cuni .cz>
2001-10-06 23:34 ` Alex Bligh - linux-kernel
2001-10-07 7:35 ` Pavel Machek
[not found] ` <Pine.LNX.3.96.1011006164044.29342B-200000@artax.karlin.mff.cuni .cz>
2001-10-06 17:59 ` Alex Bligh - linux-kernel
2001-10-06 19:13 ` Mikulas Patocka
2001-10-06 19:22 ` arjan
2001-10-06 22:36 ` Mikulas Patocka
[not found] ` <Pine.LNX.3.96.1011006210743.7808D-100000@artax.karlin.mff.cuni. cz>
2001-10-06 23:26 ` Alex Bligh - linux-kernel
2001-10-07 18:30 ` Eric W. Biederman
2001-10-08 15:01 ` Alex Bligh - linux-kernel
2001-10-07 18:32 ` Eric W. Biederman
2001-10-07 9:40 ` Alan Cox
2001-10-07 12:28 ` Mikulas Patocka
2001-10-07 14:12 ` Alan Cox
2001-10-07 15:42 ` Mikulas Patocka
2001-10-07 22:01 ` Alan Cox
2001-10-08 15:08 ` Alex Bligh - linux-kernel
2001-10-08 16:44 ` Pavel Machek
2001-10-08 22:21 ` Mikulas Patocka
2001-10-08 21:16 ` David Lang
[not found] ` <Pine.LNX.3.96.1011009001720.20446A-100000@artax.karlin.mff.cuni .cz>
2001-10-08 22:53 ` Alex Bligh - linux-kernel
2001-10-08 23:31 ` Mikulas Patocka
2001-10-08 23:44 ` Alan Cox
2001-10-08 23:46 ` Mikulas Patocka
2001-10-09 9:45 ` Pavel Machek
2001-10-08 23:48 ` Linus Torvalds
2001-10-08 23:54 ` Mikulas Patocka
2001-10-09 11:48 ` Rik van Riel
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