From: Marc Singer <elf@buici.com>
To: Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: DMA memory, split_page, BUG_ON(PageCompound()), sound
Date: Sat, 8 Jul 2006 17:07:03 -0700 [thread overview]
Message-ID: <20060709000703.GA9806@cerise.buici.com> (raw)
I'm investigating why I am triggering a BUG_ON in split_page() when I
use the sound subsystems dma memory allocation aide.
The crux of the problem appears to be that snd_malloc_dev_pages()
passes __GFP_COMP into dma_alloc_coherent(). On the ARM and several
other architectures, the dma allocation code calls split_page () with
pages allocated with this flag which, in turn, triggers the BUG_ON()
check for the CompoundPage flag.
So, the questions are these: Who is doing the wrong thing? Should the
snd_malloc_dev_pages() call drop the __GFP_COMP flag? Should
split_page() allow the page to be compound? Should __GFP_COMP be 0 on
ARM and other architectures that don't support compound pages?
next reply other threads:[~2006-07-09 0:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-09 0:07 Marc Singer [this message]
2006-07-09 3:26 ` Nick Piggin
2006-07-10 2:51 ` Marc Singer
2006-07-10 6:59 ` Nick Piggin
2006-07-10 16:26 ` Russell King
2006-07-10 17:34 ` Nick Piggin
2006-07-10 22:27 ` Marc Singer
2006-07-11 2:51 ` Marc Singer
2006-07-12 10:32 ` Russell King
2006-07-13 13:30 ` Takashi Iwai
2006-07-13 13:38 ` Nick Piggin
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