From owner-freebsd-hackers@FreeBSD.ORG  Fri Dec 15 09:19:44 2006
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From: Hans Petter Selasky <hselasky@c2i.net>
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Date: Fri, 15 Dec 2006 10:19:20 +0100
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Cc: Suleiman Souhlal <ssouhlal@freebsd.org>,
	Marc =?iso-8859-1?q?L=F6rner?= <marc.loerner@hob.de>
Subject: Re: Allocate aligned memory
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On Friday 15 December 2006 09:50, Suleiman Souhlal wrote:
> Marc L=F6rner wrote:
> > Hello all,
> >
> > I want to allocate 120KB of memory thats aligned to 32KB.
> > I already saw/found the function contigmalloc, now my question is, why
> > following functioncall never does return with an resulting address,
> > instead null is returned?
> >
> > unsigned long *p =3D (unsigned long*)
> >  contigmalloc(120*1024, M_DEVBUF, M_WAITOK, 0, (1<<22), 32*1024,
> > 1024*1024);
>
> Have you considered the fact that there might be no 32K-aligned 120KB chu=
nk
> of memory in the range you specified?
>
> My suggestion is to make the your high limit (currently 1 << 22) MUCH
> higher, if possible. Also, getting rid of the 1MB boundary might help.
>

PS: contigmalloc is on the way out. Please use "man bus_dma" instead. For a=
n=20
example see:

http://www.turbocat.net/~hselasky/isdn4bsd/sources/src/sys/dev/usb/usb_subr=
=2Ec

And the function "usbd_mem_alloc_sub()".

=2D-HPS