[NET]: Reorder some hot fields of struct net_device
Place them on separate cache lines in SMP to lower memory bouncing
between multiple CPU accessing the device.
- One part is mostly used on receive path (including
eth_type_trans()) (poll_list, poll, quota, weight, last_rx,
dev_addr, broadcast)
- One part is mostly used on queue transmit path (qdisc)
(queue_lock, qdisc, qdisc_sleeping, qdisc_list, tx_queue_len)
- One part is mostly used on xmit path (device)
(xmit_lock, xmit_lock_owner, priv, hard_start_xmit, trans_start)
'features' is placed outside of these hot points, in a location that
may be shared by all cpus (because mostly read)
name_hlist is moved close to name[IFNAMSIZ] to speedup __dev_get_by_name()
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
David S. Miller
parent
2d7ceece08
commit
9356b8fc07
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@ -265,6 +265,8 @@ struct net_device
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* the interface.
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*/
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char name[IFNAMSIZ];
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/* device name hash chain */
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struct hlist_node name_hlist;
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/*
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* I/O specific fields
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@ -292,6 +294,21 @@ struct net_device
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/* ------- Fields preinitialized in Space.c finish here ------- */
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/* Net device features */
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unsigned long features;
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#define NETIF_F_SG 1 /* Scatter/gather IO. */
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#define NETIF_F_IP_CSUM 2 /* Can checksum only TCP/UDP over IPv4. */
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#define NETIF_F_NO_CSUM 4 /* Does not require checksum. F.e. loopack. */
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#define NETIF_F_HW_CSUM 8 /* Can checksum all the packets. */
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#define NETIF_F_HIGHDMA 32 /* Can DMA to high memory. */
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#define NETIF_F_FRAGLIST 64 /* Scatter/gather IO. */
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#define NETIF_F_HW_VLAN_TX 128 /* Transmit VLAN hw acceleration */
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#define NETIF_F_HW_VLAN_RX 256 /* Receive VLAN hw acceleration */
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#define NETIF_F_HW_VLAN_FILTER 512 /* Receive filtering on VLAN */
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#define NETIF_F_VLAN_CHALLENGED 1024 /* Device cannot handle VLAN packets */
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#define NETIF_F_TSO 2048 /* Can offload TCP/IP segmentation */
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#define NETIF_F_LLTX 4096 /* LockLess TX */
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struct net_device *next_sched;
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/* Interface index. Unique device identifier */
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@ -316,9 +333,6 @@ struct net_device
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* will (read: may be cleaned up at will).
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*/
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/* These may be needed for future network-power-down code. */
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unsigned long trans_start; /* Time (in jiffies) of last Tx */
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unsigned long last_rx; /* Time of last Rx */
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unsigned short flags; /* interface flags (a la BSD) */
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unsigned short gflags;
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@ -328,15 +342,12 @@ struct net_device
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unsigned mtu; /* interface MTU value */
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unsigned short type; /* interface hardware type */
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unsigned short hard_header_len; /* hardware hdr length */
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void *priv; /* pointer to private data */
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struct net_device *master; /* Pointer to master device of a group,
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* which this device is member of.
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*/
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/* Interface address info. */
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unsigned char broadcast[MAX_ADDR_LEN]; /* hw bcast add */
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unsigned char dev_addr[MAX_ADDR_LEN]; /* hw address */
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unsigned char perm_addr[MAX_ADDR_LEN]; /* permanent hw address */
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unsigned char addr_len; /* hardware address length */
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unsigned short dev_id; /* for shared network cards */
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@ -346,8 +357,6 @@ struct net_device
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int promiscuity;
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int allmulti;
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int watchdog_timeo;
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struct timer_list watchdog_timer;
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/* Protocol specific pointers */
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@ -358,32 +367,62 @@ struct net_device
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void *ec_ptr; /* Econet specific data */
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void *ax25_ptr; /* AX.25 specific data */
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struct list_head poll_list; /* Link to poll list */
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/*
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* Cache line mostly used on receive path (including eth_type_trans())
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*/
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struct list_head poll_list ____cacheline_aligned_in_smp;
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/* Link to poll list */
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int (*poll) (struct net_device *dev, int *quota);
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int quota;
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int weight;
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unsigned long last_rx; /* Time of last Rx */
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/* Interface address info used in eth_type_trans() */
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unsigned char dev_addr[MAX_ADDR_LEN]; /* hw address, (before bcast
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because most packets are unicast) */
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unsigned char broadcast[MAX_ADDR_LEN]; /* hw bcast add */
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/*
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* Cache line mostly used on queue transmit path (qdisc)
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*/
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/* device queue lock */
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spinlock_t queue_lock ____cacheline_aligned_in_smp;
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struct Qdisc *qdisc;
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struct Qdisc *qdisc_sleeping;
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struct Qdisc *qdisc_ingress;
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struct list_head qdisc_list;
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unsigned long tx_queue_len; /* Max frames per queue allowed */
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/* ingress path synchronizer */
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spinlock_t ingress_lock;
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struct Qdisc *qdisc_ingress;
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/*
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* One part is mostly used on xmit path (device)
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*/
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/* hard_start_xmit synchronizer */
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spinlock_t xmit_lock;
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spinlock_t xmit_lock ____cacheline_aligned_in_smp;
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/* cpu id of processor entered to hard_start_xmit or -1,
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if nobody entered there.
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*/
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int xmit_lock_owner;
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/* device queue lock */
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spinlock_t queue_lock;
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void *priv; /* pointer to private data */
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int (*hard_start_xmit) (struct sk_buff *skb,
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struct net_device *dev);
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/* These may be needed for future network-power-down code. */
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unsigned long trans_start; /* Time (in jiffies) of last Tx */
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int watchdog_timeo; /* used by dev_watchdog() */
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struct timer_list watchdog_timer;
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/*
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* refcnt is a very hot point, so align it on SMP
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*/
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/* Number of references to this device */
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atomic_t refcnt;
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atomic_t refcnt ____cacheline_aligned_in_smp;
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/* delayed register/unregister */
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struct list_head todo_list;
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/* device name hash chain */
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struct hlist_node name_hlist;
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/* device index hash chain */
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struct hlist_node index_hlist;
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@ -396,21 +435,6 @@ struct net_device
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NETREG_RELEASED, /* called free_netdev */
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} reg_state;
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/* Net device features */
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unsigned long features;
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#define NETIF_F_SG 1 /* Scatter/gather IO. */
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#define NETIF_F_IP_CSUM 2 /* Can checksum only TCP/UDP over IPv4. */
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#define NETIF_F_NO_CSUM 4 /* Does not require checksum. F.e. loopack. */
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#define NETIF_F_HW_CSUM 8 /* Can checksum all the packets. */
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#define NETIF_F_HIGHDMA 32 /* Can DMA to high memory. */
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#define NETIF_F_FRAGLIST 64 /* Scatter/gather IO. */
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#define NETIF_F_HW_VLAN_TX 128 /* Transmit VLAN hw acceleration */
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#define NETIF_F_HW_VLAN_RX 256 /* Receive VLAN hw acceleration */
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#define NETIF_F_HW_VLAN_FILTER 512 /* Receive filtering on VLAN */
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#define NETIF_F_VLAN_CHALLENGED 1024 /* Device cannot handle VLAN packets */
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#define NETIF_F_TSO 2048 /* Can offload TCP/IP segmentation */
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#define NETIF_F_LLTX 4096 /* LockLess TX */
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/* Called after device is detached from network. */
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void (*uninit)(struct net_device *dev);
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/* Called after last user reference disappears. */
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@ -419,10 +443,7 @@ struct net_device
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/* Pointers to interface service routines. */
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int (*open)(struct net_device *dev);
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int (*stop)(struct net_device *dev);
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int (*hard_start_xmit) (struct sk_buff *skb,
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struct net_device *dev);
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#define HAVE_NETDEV_POLL
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int (*poll) (struct net_device *dev, int *quota);
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int (*hard_header) (struct sk_buff *skb,
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struct net_device *dev,
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unsigned short type,
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