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SubjectRe: Strange interrupt behaviour
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MOLNAR Ingo <mingo@valerie.inf.elte.hu> writes:

> are there any 16k allocations needed in RL? We need ~25 iterations to get
> a proper 16k-goal swapout. Also, this is _worst case_, when the system
> gets 'out of balance'. An NFS server doing a static rate of 16k
> allocations/deallocations will keep the 16k pool properly populated. We
> get only this worst-case scenario when we get out of balance. (which
> probably means hard trashing anyway for a couple of minutes, so spending
> CPU cycles to get it right does not seem to be a bad move)

8K rsize/wsize NFS needs 16K allocation - because the network code needs to
reserve some space for the headers, so the actual size of the skbuff data
area is about 8K + 64bytes. The result is that kmalloc chooses the next
higher power-of-2 pool = 16K.

That is one of the main reasons why NFS sucks with low memory machines
currently.

-Andi

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