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

From: David Miller
Date: Tue Apr 14 2009 - 23:24:25 EST


From: Stephen Hemminger <shemminger@xxxxxxxxxx>
Date: Tue, 14 Apr 2009 14:13:51 -0700

> This is an alternative version of ip/ip6/arp tables locking using
> per-cpu locks. This avoids the overhead of synchronize_net() during
> update but still removes the expensive rwlock in earlier versions.
>
> The idea for this came from an earlier version done by Eric Dumazet.
> Locking is done per-cpu, the fast path locks on the current cpu
> and updates counters. The slow case involves acquiring the locks on
> all cpu's.
>
> The mutex that was added for 2.6.30 in xt_table is unnecessary since
> there already is a mutex for xt[af].mutex that is held.
>
> Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx>

Things seem to be winding down, good. :-)

I'll let Patrick McHardy merge this to me with his other pending
netfilter fixes.

Thanks!
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