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Subject[PATCH] net: deinline netif_tx_stop_all_queues(), remove WARN_ON in netif_tx_stop_queue()
Date
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
---
include/linux/netdevice.h | 14 +-------------
net/core/dev.c | 11 +++++++++++
2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index dcf6ec2..536169e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2548,10 +2548,6 @@ 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);
}

@@ -2567,15 +2563,7 @@ 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..11e0128 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6261,6 +6261,17 @@ 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
--
1.8.1.4


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