Re: [PATCH] netfilter: revised locking for x_tables

From: Linus Torvalds
Date: Tue Apr 28 2009 - 13:06:23 EST




Ack.

It could do with the update from Eric about how non-current CPU writelocks
only require preemp-disable around get_counters() (and then the
local_bh_disable() only around the current-CPU case).

I _think_ get_counters() is the only case that can use that optimization,
but it's quite possible that it's worth doing especially for machines with
lots of cores, if BH latency is an issue (and it might be).

Of course, for the lots-and-lots of cores case, even the preemption
disable might be an issue. And then it really does get much more
complicated. At that point, you probably want the RCU thing.

Linus
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