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authorSebastian Siewior <bigeasy@linutronix.de>2013-12-12 10:15:59 +0100
committerDavid S. Miller <davem@davemloft.net>2013-12-12 15:35:09 -0500
commita0a9663dd2146d54339237764e1bfc60e8a39328 (patch)
treeba691d621e527466f5a2a3e47135f35948b167a1
parentf280e89ad6a29d9969cb6b216123c798e1689bc4 (diff)
net: make neigh_priv_len in struct net_device 16bit instead of 8bit
neigh_priv_len is defined as u8. With all debug enabled struct ipoib_neigh has 200 bytes. The largest part is sk_buff_head with 96 bytes and here the spinlock with 72 bytes. The size value still fits in this u8 leaving some room for more. On -RT struct ipoib_neigh put on weight and has 392 bytes. The main reason is sk_buff_head with 288 and the fatty here is spinlock with 192 bytes. This does no longer fit into into neigh_priv_len and gcc complains. This patch changes neigh_priv_len from being 8bit to 16bit. Since the following element (dev_id) is 16bit followed by a spinlock which is aligned, the struct remains with a total size of 3200 (allmodconfig) / 2048 (with as much debug off as possible) bytes on x86-64. On x86-32 the struct is 1856 (allmodconfig) / 1216 (with as much debug off as possible) bytes long. The numbers were gained with and without the patch to prove that this change does not increase the size of the struct. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netdevice.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7f0ed423a360..d9a550bf3e8e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1255,7 +1255,7 @@ struct net_device {
unsigned char perm_addr[MAX_ADDR_LEN]; /* permanent hw address */
unsigned char addr_assign_type; /* hw address assignment type */
unsigned char addr_len; /* hardware address length */
- unsigned char neigh_priv_len;
+ unsigned short neigh_priv_len;
unsigned short dev_id; /* Used to differentiate devices
* that share the same link
* layer address