From 2bdfe0baeca0e2750037b8fba71905c00ac3c515 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 26 Oct 2006 15:46:54 -0700 Subject: [PATCH] netpoll retry cleanup The netpoll beast was still not happy. If the beast got clogged pipes, it tended to stare blankly off in space for a long time. The problem couldn't be completely fixed because the beast talked with irq's disabled. But it could be made less painful and shorter. Signed-off-by: Stephen Hemminger --- include/linux/netpoll.h | 1 - net/core/netpoll.c | 71 +++++++++++++++++++++++-------------------------- 2 files changed, 33 insertions(+), 39 deletions(-) diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 93a8b76..c65d12e 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -28,7 +28,6 @@ struct netpoll_info { atomic_t refcnt; spinlock_t poll_lock; int poll_owner; - int tries; int rx_flags; spinlock_t rx_lock; struct netpoll *rx_np; /* netpoll that registered an rx_hook */ diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 93cb828..6b34c39 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -34,12 +34,12 @@ #define MAX_UDP_CHUNK 1460 #define MAX_SKBS 32 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2) -#define MAX_RETRIES 20000 static struct sk_buff_head skb_pool; static atomic_t trapped; +#define USEC_PER_POLL 50 #define NETPOLL_RX_ENABLED 1 #define NETPOLL_RX_DROP 2 @@ -72,6 +72,7 @@ static void queue_process(void *p) schedule_delayed_work(&npinfo->tx_work, HZ/10); return; } + netif_tx_unlock_bh(dev); } } @@ -244,50 +245,44 @@ repeat: static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) { - int status; - struct netpoll_info *npinfo; + int status = NETDEV_TX_BUSY; + unsigned long tries; + struct net_device *dev = np->dev; + struct netpoll_info *npinfo = np->dev->npinfo; + + if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { + __kfree_skb(skb); + return; + } + + /* don't get messages out of order, and no recursion */ + if ( !(np->drop == netpoll_queue && skb_queue_len(&npinfo->txq)) + && npinfo->poll_owner != smp_processor_id() + && netif_tx_trylock(dev)) { + + /* try until next clock tick */ + for(tries = jiffies_to_usecs(1)/USEC_PER_POLL; tries > 0; --tries) { + if (!netif_queue_stopped(dev)) + status = dev->hard_start_xmit(skb, dev); + + if (status == NETDEV_TX_OK) + break; - if (!np || !np->dev || !netif_running(np->dev)) { - __kfree_skb(skb); - return; - } + /* tickle device maybe there is some cleanup */ + netpoll_poll(np); - npinfo = np->dev->npinfo; + udelay(USEC_PER_POLL); + } + netif_tx_unlock(dev); + } - /* avoid recursion */ - if (npinfo->poll_owner == smp_processor_id() || - np->dev->xmit_lock_owner == smp_processor_id()) { + if (status != NETDEV_TX_OK) { + /* requeue for later */ if (np->drop) np->drop(skb); else __kfree_skb(skb); - return; } - - do { - npinfo->tries--; - netif_tx_lock(np->dev); - - /* - * network drivers do not expect to be called if the queue is - * stopped. - */ - status = NETDEV_TX_BUSY; - if (!netif_queue_stopped(np->dev)) - status = np->dev->hard_start_xmit(skb, np->dev); - - netif_tx_unlock(np->dev); - - /* success */ - if(!status) { - npinfo->tries = MAX_RETRIES; /* reset */ - return; - } - - /* transmit busy */ - netpoll_poll(np); - udelay(50); - } while (npinfo->tries > 0); } void netpoll_send_udp(struct netpoll *np, const char *msg, int len) @@ -649,7 +644,7 @@ int netpoll_setup(struct netpoll *np) npinfo->rx_np = NULL; spin_lock_init(&npinfo->poll_lock); npinfo->poll_owner = -1; - npinfo->tries = MAX_RETRIES; + spin_lock_init(&npinfo->rx_lock); skb_queue_head_init(&npinfo->arp_tx); skb_queue_head_init(&npinfo->txq); -- 2.7.4