Re: Slab allocators: Define common size limitations

From: Geert Uytterhoeven
Date: Thu May 17 2007 - 04:45:21 EST


On Wed, 16 May 2007, Arnd Bergmann wrote:
> On Wednesday 16 May 2007, Geert Uytterhoeven wrote:
> > What are the changes a large allocation will actually succeed?
> > Is there an alignment rule for large allocations?
> >
> > E.g. for one of the PS3 drivers I need a physically contiguous 256 KiB-aligned
> > block of 256 KiB. Currently I'm using __alloc_bootmem() for that, but maybe
> > kmalloc() becomes a suitable alternative now?
>
> kmalloc is limited to 128KiB on most architectures. Normally there is no
> need to use it anyway, just use __get_free_pages(). It will generally
> succeed at early boot time, but not after the system has been running
> for some time.

Exactly my understanding. And __get_free_pages() returns PAGE_SIZE-aligned
memory. So I'll keep the current code.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- Sony Network and Software Technology Center Europe (NSCE)
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