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Subject: Re: using kmalloc
To: dmaas@dcine.com (Dan Maas)
Date: Wed, 20 Mar 2002 10:27:09 +0000 (GMT)
Cc: cvaka_kernel@yahoo.com (chiranjeevi vaka), linux-kernel@vger.kernel.org
In-Reply-To: <010101c1cfd3$8a87cfd0$1a02a8c0@allyourbase> from "Dan Maas" at Mar 20, 2002 12:53:20 AM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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> To allocate more memory, use vmalloc(), which allocates and maps physically
> disjoint pages into a virtually-contiguous region. Be careful when doing DMA
> to a vmalloc() area, since it is not physically contiguous and exists only
> in the kernel's virtual memory map... Also I believe vmalloc()ed memory is
> only accessible from (the context of) the process in which it was allocated
> (?).

vmalloc memory is accessible everywhere. You can't allocate it during 
interrupts or tasklets, and you will get deadlocks if you allocate it in the
write out path of a file system/disk driver.

Alan
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