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From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc-embedded@ozlabs.org
Subject: Re: Allocalting > 4M
Date: Wed, 27 Sep 2006 23:00:16 +0200
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Am Wednesday 27 September 2006 22:34 schrieb Rune Torgersen:
> Is there any way, short of using mem= on kernel command line and
> reserving memory, to allocate more than 4M of contigous physical memory?
> We're trying to allocalte a 8M buffer for use in some DMA transfers for
> a bank of DSP's.
> We were using get_Free_pages to allocate the meory before we made the
> buffer bigger. It seems that get_free_pages cannot allocate more than
> 2^10 pages (4M on ppc)
> I also tried alloc_bootmem, but it fails also.

alloc_bootmem is supposed to handle this case, but you can only call
that very early in your code, before the buddy allocator kicks in
(free_all_bootmem()). Maybe you should just check why it fails for you.

	Arnd <><