From 2561cc15e3816e4323f9e79a6890bff94c0bbec2 Mon Sep 17 00:00:00 2001 From: Zoltan Kiss Date: Mon, 11 Aug 2014 13:01:44 +0100 Subject: xen-netback: Don't deschedule NAPI when carrier off In the patch called "xen-netback: Turn off the carrier if the guest is not able to receive" NAPI was descheduled when the carrier was set off. That's not what most of the drivers do, and we don't have any specific reason to do so as well, so revert that change. Signed-off-by: Zoltan Kiss Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xenproject.org Acked-by: Wei Liu Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 48a55cda979b..bfd10cb9c8de 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -78,12 +78,8 @@ int xenvif_poll(struct napi_struct *napi, int budget) /* This vif is rogue, we pretend we've there is nothing to do * for this vif to deschedule it from NAPI. But this interface * will be turned off in thread context later. - * Also, if a guest doesn't post enough slots to receive data on one of - * its queues, the carrier goes down and NAPI is descheduled here so - * the guest can't send more packets until it's ready to receive. */ - if (unlikely(queue->vif->disabled || - !netif_carrier_ok(queue->vif->dev))) { + if (unlikely(queue->vif->disabled)) { napi_complete(napi); return 0; } -- cgit From ea2c5e134237eadc9924ce821ded678750024549 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Tue, 12 Aug 2014 11:48:06 +0100 Subject: xen-netback: move NAPI add/remove calls Originally netif_napi_add was in xenvif_init_queue and netif_napi_del was in xenvif_deinit_queue, while kthreads were handled in xenvif_connect and xenvif_disconnect. Move netif_napi_add and netif_napi_del to xenvif_connect and xenvif_disconnect so that they reside together with kthread operations. Signed-off-by: Wei Liu Cc: Ian Campbell Cc: Zoltan Kiss Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index bfd10cb9c8de..5f3d6c06fcf7 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -524,9 +524,6 @@ int xenvif_init_queue(struct xenvif_queue *queue) init_timer(&queue->rx_stalled); - netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll, - XENVIF_NAPI_WEIGHT); - return 0; } @@ -614,6 +611,9 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref, wake_up_process(queue->task); wake_up_process(queue->dealloc_task); + netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll, + XENVIF_NAPI_WEIGHT); + return 0; err_rx_unbind: @@ -672,6 +672,8 @@ void xenvif_disconnect(struct xenvif *vif) for (queue_index = 0; queue_index < num_queues; ++queue_index) { queue = &vif->queues[queue_index]; + netif_napi_del(&queue->napi); + if (queue->task) { del_timer_sync(&queue->rx_stalled); kthread_stop(queue->task); @@ -704,7 +706,6 @@ void xenvif_disconnect(struct xenvif *vif) void xenvif_deinit_queue(struct xenvif_queue *queue) { free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages); - netif_napi_del(&queue->napi); } void xenvif_free(struct xenvif *vif) -- cgit From a64bd934528e26e8956112e43a279fba2ee0634e Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Tue, 12 Aug 2014 11:48:07 +0100 Subject: xen-netback: don't stop dealloc kthread too early Reference count the number of packets in host stack, so that we don't stop the deallocation thread too early. If not, we can end up with xenvif_free permanently waiting for deallocation thread to unmap grefs. Reported-by: Thomas Leonard Signed-off-by: Wei Liu Cc: Ian Campbell Cc: Zoltan Kiss Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 5f3d6c06fcf7..0aaca902699a 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -43,6 +43,23 @@ #define XENVIF_QUEUE_LENGTH 32 #define XENVIF_NAPI_WEIGHT 64 +/* This function is used to set SKBTX_DEV_ZEROCOPY as well as + * increasing the inflight counter. We need to increase the inflight + * counter because core driver calls into xenvif_zerocopy_callback + * which calls xenvif_skb_zerocopy_complete. + */ +void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue, + struct sk_buff *skb) +{ + skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; + atomic_inc(&queue->inflight_packets); +} + +void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue) +{ + atomic_dec(&queue->inflight_packets); +} + static inline void xenvif_stop_queue(struct xenvif_queue *queue) { struct net_device *dev = queue->vif->dev; @@ -557,6 +574,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref, init_waitqueue_head(&queue->wq); init_waitqueue_head(&queue->dealloc_wq); + atomic_set(&queue->inflight_packets, 0); if (tx_evtchn == rx_evtchn) { /* feature-split-event-channels == 0 */ -- cgit From b1252858213f39700dac1bc3295b6e88f6cce24b Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Tue, 12 Aug 2014 11:48:08 +0100 Subject: xen-netback: remove loop waiting function The original implementation relies on a loop to check if all inflight packets are freed. Now we have proper reference counting, there's no need to use loop anymore. Signed-off-by: Wei Liu Cc: Ian Campbell Cc: Zoltan Kiss Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 29 ----------------------------- 1 file changed, 29 deletions(-) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 0aaca902699a..e29e15dca86e 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -660,25 +660,6 @@ void xenvif_carrier_off(struct xenvif *vif) rtnl_unlock(); } -static void xenvif_wait_unmap_timeout(struct xenvif_queue *queue, - unsigned int worst_case_skb_lifetime) -{ - int i, unmap_timeout = 0; - - for (i = 0; i < MAX_PENDING_REQS; ++i) { - if (queue->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) { - unmap_timeout++; - schedule_timeout(msecs_to_jiffies(1000)); - if (unmap_timeout > worst_case_skb_lifetime && - net_ratelimit()) - netdev_err(queue->vif->dev, - "Page still granted! Index: %x\n", - i); - i = -1; - } - } -} - void xenvif_disconnect(struct xenvif *vif) { struct xenvif_queue *queue = NULL; @@ -731,21 +712,11 @@ void xenvif_free(struct xenvif *vif) struct xenvif_queue *queue = NULL; unsigned int num_queues = vif->num_queues; unsigned int queue_index; - /* Here we want to avoid timeout messages if an skb can be legitimately - * stuck somewhere else. Realistically this could be an another vif's - * internal or QDisc queue. That another vif also has this - * rx_drain_timeout_msecs timeout, so give it time to drain out. - * Although if that other guest wakes up just before its timeout happens - * and takes only one skb from QDisc, it can hold onto other skbs for a - * longer period. - */ - unsigned int worst_case_skb_lifetime = (rx_drain_timeout_msecs/1000); unregister_netdev(vif->dev); for (queue_index = 0; queue_index < num_queues; ++queue_index) { queue = &vif->queues[queue_index]; - xenvif_wait_unmap_timeout(queue, worst_case_skb_lifetime); xenvif_deinit_queue(queue); } -- cgit