Re: Limitation of buffer allocation

["Stephen C. Tweedie" <sct@redhat.com>]

Hi,

On Fri, 17 Dec 1999 14:43:12 +0100, Peter Wurbs <wurbs@bbcom-hh.de>
said:

> If there is a ad-hoc requierement of a bigger memory block, this
> function seems to be unable to take away memory from the buffer cache.
> Thus alloc_skb returns null pointer, because it must be invoked with
> flag "GFP_ATOMIC" (sudden return if there is no memory available). As a
> result the driver runs into a faulty deadlocked state.

Yes, that's all working exactly as expected.

GFP_ATOMIC allocations are always expected to fail immediately if there
is insufficient memory available.  If you want to keep a
larger-than-normal amount of free space available for atomica
llocations, then increase the free pages count in
/proc/sys/vm/freepages. 

> Do you see problems in changing the values in /proc/sys/vm/freepages?

No, that's precisely what you are supposed to do!

--Stephen
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