Re: [PATCH] netfilter: use per-cpu spinlock rather than RCU (v3)

David Miller
2009-04-17T08:07:42Z

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Thu, 16 Apr 2009 22:40:32 -0700

> I completely agree that this RCU is absolutely -not- 2.6.30 material. ;-)

I don't understand why we're writing such complicated code.

Oh I see why, it's because not every arch uses the generic SMP helpers
yet :-)

Because if they did universally, we could solve this problem so
simply, by merely sending a remote softirq to every online cpu. Once
those all complete we have enough of a quiesce period, every cpu must
have exited any netfilter packet processing code path they were in.

And we could know they complete using an atomic counter or something.