These functions compile to ~60 bytes of machine code each. With this .config: http://busybox.net/~vda/kernel_config there are 617 calls to netif_tx_stop_queue() and 49 calls to netif_tx_stop_all_queues() in vmlinux. Code size is reduced by 27 kbytes: text data bss dec hex filename 82426986 22255416 20627456 125309858 77813a2 vmlinux.before 82399481 22255416 20627456 125282353 777a831 vmlinux It may seem strange that a seemingly simple code like one in netif_tx_stop_queue() compiles to ~60 bytes of code. Well, it's true. Here's its disassembly: netif_tx_stop_queue: e8 b0 15 4d 00 callq <__fentry__> 48 85 ff test %rdi,%rdi 75 25 jne <netif_tx_stop_queue+0x2f> 55 push %rbp be 7a 18 00 00 mov $0x187a,%esi 48 c7 c7 50 59 d8 85 mov $.rodata+0x1d85950,%rdi 48 89 e5 mov %rsp,%rbp e8 54 5a 7d fd callq <warn_slowpath_null> 48 c7 c7 5f 59 d8 85 mov $.rodata+0x1d8595f,%rdi 31 c0 xor %eax,%eax e8 b0 47 48 00 callq <printk> eb 09 jmp <netif_tx_stop_queue+0x38> f0 80 8f e0 01 00 00 01 lock orb $0x1,0x1e0(%rdi) c3 retq 5d pop %rbp c3 retq This causes gcc to auto-deinline it before this patch, but with 203 separate copies in each module which uses this function: $ nm --size-sort vmlinux.before | grep -e ' netif_tx_stop_queue$' | wc -l 203 Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx> CC: David S. Miller <davem@xxxxxxxxxxxxx> CC: Jiri Pirko <jpirko@xxxxxxxxxx> CC: linux-kernel@xxxxxxxxxxxxxxx CC: netdev@xxxxxxxxxxxxxxx CC: netfilter-devel@xxxxxxxxxxxxxxx --- include/linux/netdevice.h | 19 ++----------------- net/core/dev.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+), 17 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index dcf6ec2..f650d16 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2546,14 +2546,7 @@ static inline void netif_tx_wake_all_queues(struct net_device *dev) } } -static inline void netif_tx_stop_queue(struct netdev_queue *dev_queue) -{ - if (WARN_ON(!dev_queue)) { - pr_info("netif_stop_queue() cannot be called before register_netdev()\n"); - return; - } - set_bit(__QUEUE_STATE_DRV_XOFF, &dev_queue->state); -} +void netif_tx_stop_queue(struct netdev_queue *dev_queue); /** * netif_stop_queue - stop transmitted packets @@ -2567,15 +2560,7 @@ static inline void netif_stop_queue(struct net_device *dev) netif_tx_stop_queue(netdev_get_tx_queue(dev, 0)); } -static inline void netif_tx_stop_all_queues(struct net_device *dev) -{ - unsigned int i; - - for (i = 0; i < dev->num_tx_queues; i++) { - struct netdev_queue *txq = netdev_get_tx_queue(dev, i); - netif_tx_stop_queue(txq); - } -} +void netif_tx_stop_all_queues(struct net_device *dev); static inline bool netif_tx_queue_stopped(const struct netdev_queue *dev_queue) { diff --git a/net/core/dev.c b/net/core/dev.c index 962ee9d..569031f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6261,6 +6261,27 @@ static int netif_alloc_netdev_queues(struct net_device *dev) return 0; } +void netif_tx_stop_queue(struct netdev_queue *dev_queue) +{ + if (WARN_ON(!dev_queue)) { + pr_info("netif_stop_queue() cannot be called before register_netdev()\n"); + return; + } + set_bit(__QUEUE_STATE_DRV_XOFF, &dev_queue->state); +} +EXPORT_SYMBOL(netif_tx_stop_queue); + +void netif_tx_stop_all_queues(struct net_device *dev) +{ + unsigned int i; + + for (i = 0; i < dev->num_tx_queues; i++) { + struct netdev_queue *txq = netdev_get_tx_queue(dev, i); + netif_tx_stop_queue(txq); + } +} +EXPORT_SYMBOL(netif_tx_stop_all_queues); + /** * register_netdevice - register a network device * @dev: device to register -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
