inetpeer: restore small inet_peer structures

Addition of rcu_head to struct inet_peer added 16bytes on 64bit arches.

Thats a bit unfortunate, since old size was exactly 64 bytes.

This can be solved, using an union between this rcu_head an four fields,
that are normally used only when a refcount is taken on inet_peer.
rcu_head is used only when refcnt=-1, right before structure freeing.

Add a inet_peer_refcheck() function to check this assertion for a while.

We can bring back SLAB_HWCACHE_ALIGN qualifier in kmem cache creation.

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/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 349249fad2db..9ffa24b9a804 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -64,7 +64,7 @@
  *                 usually under some other lock to prevent node disappearing
  *              dtime: unused node list lock
  *              v4daddr: unchangeable
- *              ip_id_count: idlock
+ *              ip_id_count: atomic value (no lock needed)
  */
 
 static struct kmem_cache *peer_cachep __read_mostly;
@@ -129,7 +129,7 @@ void __init inet_initpeers(void)
 
         peer_cachep = kmem_cache_create("inet_peer_cache",
                         sizeof(struct inet_peer),
-                        0, SLAB_PANIC,
+                        0, SLAB_HWCACHE_ALIGN | SLAB_PANIC,
                         NULL);
 
         /* All the timers, started at system startup tend