Commit a2029240 authored May 11, 2015 by Denys Vlasenko Committed by David S. Miller May 12, 2015

net: deinline netif_tx_stop_all_queues(), remove WARN_ON in netif_tx_stop_queue()

These functions compile to 60 bytes of machine code each.
With this .config: http://busybox.net/~vda/kernel_config


there are 617 calls of netif_tx_stop_queue()
and 49 calls of netif_tx_stop_all_queues() in vmlinux.

To fix this, remove WARN_ON in netif_tx_stop_queue()
as suggested by davem, and deinline netif_tx_stop_all_queues().

Change in code size is about 20k:

   text      data      bss       dec     hex filename
82426986 22255416 20627456 125309858 77813a2 vmlinux.before
82406248 22255416 20627456 125289120 777c2a0 vmlinux

gcc-4.7.2 still creates deinlined version of netif_tx_stop_queue
sometimes:

$ nm --size-sort vmlinux | grep netif_tx_stop_queue | wc -l
190

ffffffff81b558a8 <netif_tx_stop_queue>:
ffffffff81b558a8:       55                      push   %rbp
ffffffff81b558a9:       48 89 e5                mov    %rsp,%rbp
ffffffff81b558ac:       f0 80 8f e0 01 00 00    lock orb $0x1,0x1e0(%rdi)
ffffffff81b558b3:       01
ffffffff81b558b4:       5d                      pop    %rbp
ffffffff81b558b5:       c3                      retq

This needs additional fixing.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Alexei Starovoitov <alexei.starovoitov@gmail.com>
CC: Alexander Duyck <alexander.duyck@gmail.com>
CC: Joe Perches <joe@perches.com>
CC: David S. Miller <davem@davemloft.net>
CC: Jiri Pirko <jpirko@redhat.com>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
CC: netfilter-devel@vger.kernel.org
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b5082083

include/linux/netdevice.h

+1 −13

Original line number	Diff line number	Diff line
		@@ -2559,10 +2559,6 @@ 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);
		}

		@@ -2578,15 +2574,7 @@ 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)
		{

net/core/dev.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -6301,6 +6301,17 @@ static int netif_alloc_netdev_queues(struct net_device *dev)
		return 0;
		}

		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