David Miller wrote:

From: Andi Kleen <redacted>
Date: Thu, 28 Aug 2008 09:45:36 +0200

quoted

quoted

When scanning route cache hash table, we can avoid taking locks for empty 
buckets.

I'm not sure it's worth it in this case.  A rcu_read_lock() is a nop
(on non preemptible kernel) to very cheap (non atomic increment/decrement in 
cached task_struct) 

It's not one, it's at least two such increments, plus function calls,
state checks, etc. since this is rcu_read_lock_bh().

I'm very happy to see some progress on this and this leading to even more 
optimalizations elsewhere,

Thanks guys!

Regards,

Hans


p.s.

Can I please be removed from the CC, thanks!