From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pekka Enberg <penberg-bbCR+/B0CizivPeTLB3BmA@public.gmane.org>
Subject: Re: [Bug #13319] Page allocation failures with b43 and p54usb
Date: Mon, 8 Jun 2009 13:52:05 +0300
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To: Mel Gorman <mel-wPRd99KPJ+uzQB+pC5nmwQ@public.gmane.org>
Cc: Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Larry Finger <Larry.Finger-tQ5ms3gMjBLk1uMJSBkQmQ@public.gmane.org>, "Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>, Linux Kernel Mailing List <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Kernel Testers List <kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, KOSAKI Motohiro <kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>, Christoph Lameter <cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>

On Mon, Jun 8, 2009 at 1:17 PM, Mel Gorman<mel-wPRd99KPJ+uzQB+pC5nmwQ@public.gmane.org> wrote:
> Pekka, assuming the request size is 800 bytes, and SLUB is using order-1
> pages for allocations of that size, what happened order-1 allocations
> falling back to order-0 allocations as necessary. That logic exists,
> right? If so, could it be broken?

That logic is in allocate_slab() and if the higher order allocation
fails, we fall-back to struct kmem_cache ->min order. That in turn is
set up in calculate_sizes() to get_order(size) so it seems pretty
unlikely to me the allocation is 800 bytes. Of course, I could be
missing something here and there's a bug in oo_make() or oo_order().
Hmm.

                        Pekka