Re: [PATCH] net: fib: fix incorrect call_rcu_bh()

On Tue, 2012-08-07 at 09:34 -0700, Paul E. McKenney wrote:

On Tue, Aug 07, 2012 at 12:47:11PM +0200, Eric Dumazet wrote:

quoted

From: Eric Dumazet <edumazet@google.com>

After IP route cache removal, I believe rcu_bh() has very little use and
we should remove this RCU variant, since it adds some cycles in fast
path.

Do you mean remove all uses of RCU-bh globally and also removing the
implementation itself?  That would actually be a good thing, from my
perspective.

Yes I meant that there are now too few rcu_bh users, and that they
probably could switch to regular rcu.

We could then remove the implementation.

rcu_bh was needed because we could sit forever in softirq mode in one
cpu, and we needed to allocate/free dsts with RCU protection.