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Date: Fri, 15 Dec 2006 00:50:38 -0800
From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: Allocate aligned memory
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Marc Lörner 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 = (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 chunk 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.

-- Suleiman