Allocalting > 4M

Roger Larsson roger.larsson at norran.net
Thu Sep 28 06:58:26 EST 2006


On Wednesday 27 September 2006 22:34, Rune Torgersen wrote:
> We have an embedded board with 1G of memory.
>
> 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.

There is a 'bigphysmem' patch for 2.4 that might help. There might be
alternative solutions to this problem, they should refere to bigphysmem
- might help when googling...

/RogerL



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