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authorLeesoo Ahn <lsahn@ooseel.net>2023-01-06 13:49:49 +0300
committerDavid S. Miller <davem@davemloft.net>2023-01-09 10:23:54 +0300
commitfb59bf28cd638a0b8671bf90b6692fea4898d207 (patch)
tree3ba09d4ed9ffa305b95184d75b6e02b9259bd0e8 /drivers/net
parent9cb8bae3d17b517abba74c13dd0327653b9142a4 (diff)
downloadlinux-fb59bf28cd638a0b8671bf90b6692fea4898d207.tar.xz
usbnet: optimize usbnet_bh() to reduce CPU load
The current source pushes skb into dev-done queue by calling skb_dequeue_tail() and then pop it by skb_dequeue() to branch to rx_cleanup state for freeing urb/skb in usbnet_bh(). It takes extra CPU load, 2.21% (skb_queue_tail) as follows, - 11.58% 0.26% swapper [k] usbnet_bh - 11.32% usbnet_bh - 6.43% skb_dequeue 6.34% _raw_spin_unlock_irqrestore - 2.21% skb_queue_tail 2.19% _raw_spin_unlock_irqrestore - 1.68% consume_skb - 0.97% kfree_skbmem 0.80% kmem_cache_free 0.53% skb_release_data To reduce the extra CPU load use return values to call helper function usb_free_skb() to free the resources instead of calling skb_queue_tail() and skb_dequeue() for push and pop respectively. - 7.87% 0.25% swapper [k] usbnet_bh - 7.62% usbnet_bh - 4.81% skb_dequeue 4.74% _raw_spin_unlock_irqrestore - 1.75% consume_skb - 0.98% kfree_skbmem 0.78% kmem_cache_free 0.58% skb_release_data 0.53% smsc95xx_rx_fixup Signed-off-by: Leesoo Ahn <lsahn@ooseel.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/usb/usbnet.c29
1 files changed, 17 insertions, 12 deletions
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 64a9a80b2309..283ffddda821 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -555,32 +555,30 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
/*-------------------------------------------------------------------------*/
-static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
+static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
{
if (dev->driver_info->rx_fixup &&
!dev->driver_info->rx_fixup (dev, skb)) {
/* With RX_ASSEMBLE, rx_fixup() must update counters */
if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
dev->net->stats.rx_errors++;
- goto done;
+ return -EPROTO;
}
// else network stack removes extra byte if we forced a short packet
/* all data was already cloned from skb inside the driver */
if (dev->driver_info->flags & FLAG_MULTI_PACKET)
- goto done;
+ return -EALREADY;
if (skb->len < ETH_HLEN) {
dev->net->stats.rx_errors++;
dev->net->stats.rx_length_errors++;
netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
- } else {
- usbnet_skb_return(dev, skb);
- return;
+ return -EPROTO;
}
-done:
- skb_queue_tail(&dev->done, skb);
+ usbnet_skb_return(dev, skb);
+ return 0;
}
/*-------------------------------------------------------------------------*/
@@ -1514,6 +1512,14 @@ err:
return ret;
}
+static inline void usb_free_skb(struct sk_buff *skb)
+{
+ struct skb_data *entry = (struct skb_data *)skb->cb;
+
+ usb_free_urb(entry->urb);
+ dev_kfree_skb(skb);
+}
+
/*-------------------------------------------------------------------------*/
// tasklet (work deferred from completions, in_irq) or timer
@@ -1528,15 +1534,14 @@ static void usbnet_bh (struct timer_list *t)
entry = (struct skb_data *) skb->cb;
switch (entry->state) {
case rx_done:
- entry->state = rx_cleanup;
- rx_process (dev, skb);
+ if (rx_process(dev, skb))
+ usb_free_skb(skb);
continue;
case tx_done:
kfree(entry->urb->sg);
fallthrough;
case rx_cleanup:
- usb_free_urb (entry->urb);
- dev_kfree_skb (skb);
+ usb_free_skb(skb);
continue;
default:
netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);