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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-16 02:58:13 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-16 21:58:44 -0700 |
| commit | cd13539b8bc9ae884e6d8d9374c594adff4304e4 (patch) | |
| tree | 6adc13bc1dfe5da2480f5d2186e2719f5f2b713f | |
| parent | 94767632623c7bf5b16a0cf963ec93a8ad9acca4 (diff) | |
| download | op-kernel-dev-cd13539b8bc9ae884e6d8d9374c594adff4304e4.zip op-kernel-dev-cd13539b8bc9ae884e6d8d9374c594adff4304e4.tar.gz | |
net: shrinks struct net_device
commit ab95bfe01 (net: replace hooks in __netif_receive_skb) added
rx_handler at wrong place, between two cache line aligned objects,
creating a big hole (a full cache line)
Move rx_handler and rx_handler_data before rx_queue, filling existing
hole.
Move master field in the cache line(s) used in receive path.
This saves 64 bytes (or L1_CACHE_BYTES), and avoids two possible
cache misses in receive path.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/netdevice.h | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 8992fff..ec17887 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -918,10 +918,6 @@ struct net_device { unsigned short needed_headroom; unsigned short needed_tailroom; - struct net_device *master; /* Pointer to master device of a group, - * which this device is member of. - */ - /* Interface address info. */ unsigned char perm_addr[MAX_ADDR_LEN]; /* permanent hw address */ unsigned char addr_assign_type; /* hw address assignment type */ @@ -951,7 +947,7 @@ struct net_device { assign before registering */ /* - * Cache line mostly used on receive path (including eth_type_trans()) + * Cache lines mostly used on receive path (including eth_type_trans()) */ unsigned long last_rx; /* Time of last Rx * This should not be set in @@ -961,6 +957,10 @@ struct net_device { * avoid dirtying this cache line. */ + struct net_device *master; /* Pointer to master device of a group, + * which this device is member of. + */ + /* Interface address info used in eth_type_trans() */ unsigned char *dev_addr; /* hw address, (before bcast because most packets are @@ -980,10 +980,14 @@ struct net_device { unsigned int num_rx_queues; #endif - struct netdev_queue rx_queue; rx_handler_func_t *rx_handler; void *rx_handler_data; + struct netdev_queue rx_queue; /* use two cache lines */ + +/* + * Cache lines mostly used on transmit path + */ struct netdev_queue *_tx ____cacheline_aligned_in_smp; /* Number of TX queues allocated at alloc_netdev_mq() time */ @@ -997,9 +1001,7 @@ struct net_device { unsigned long tx_queue_len; /* Max frames per queue allowed */ spinlock_t tx_global_lock; -/* - * One part is mostly used on xmit path (device) - */ + /* These may be needed for future network-power-down code. */ /* |
