Quoting "David S. Miller" <davem@xxxxxxxxxx>:
> There are methods to eliminate the centrality of the
> port allocation locking.
>
> Basically, kill tcp_portalloc_lock and make the port rover be
> per-cpu.
Aha! Exactly what I started to do quite a while ago..
> The only tricky case is the "out of ports" situation. Because
> there is no centralized locking being used to serialize port
> allocation, it is difficult to be sure that the port space is truly
> exhausted.
I decided to use a stupid global flag to signal this..It did become
messy and I didnt finalize everything. Then my day job
intervened :). Still hoping for spare time*5 to complete
this if none comes up with something before then..
> Another idea, which doesn't eliminate the tcp_portalloc_lock but
> has other good SMP properties, is to apply a "cpu salt" to the
> port rover value. For example, shift the local cpu number into
> the upper parts of a 'u16', then 'xor' that with tcp_port_rover.
nice..any patch extant? :)
thanks,
Nivedita
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