neigh: Convert garbage collection from softirq to workqueue

Current neigh_periodic_timer() function is fired by timer IRQ, and
scans one hash bucket each round (very litle work in fact)

As we are supposed to scan whole hash table in 15 seconds, this means
neigh_periodic_timer() can be fired very often. (depending on the number
of concurrent hash entries we stored in this table)

Converting this to a workqueue permits scanning whole table, minimizing
icache pollution, and firing this work every 15 seconds, independantly
of hash table size.

This 15 seconds delay is not a hard number, as work is a deferrable one.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index d8d790e56d3d..18b69b6cecaf 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -24,6 +24,7 @@
 
 #include <linux/err.h>
 #include <linux/sysctl.h>
+#include <linux/workqueue.h>
 #include <net/rtnetlink.h>
 
 /*
@@ -167,7 +168,7 @@ struct neigh_table
         int                     gc_thresh2;
         int                     gc_thresh3;
         unsigned long           last_flush;
-        struct timer_list       gc_timer;
+        struct delayed_work     gc_work;
         struct timer_list       proxy_timer;
         struct sk_buff_head     proxy_queue;
         atomic_t                entries;
@@ -178,7 +179,6 @@ struct neigh_table
         struct neighbour        **hash_buckets;
         unsigned int            hash_mask;
         __u32                   hash_rnd;
-        unsigned int            hash_chain_gc;
         struct pneigh_entry     **phash_buckets;
 };