From f51de24356e49e4dcb5095e87717065580912120 Mon Sep 17 00:00:00 2001 From: Zoltan Kiss Date: Tue, 8 Jul 2014 19:49:14 +0100 Subject: [PATCH] xen-netback: Adding debugfs "io_ring_qX" files This patch adds debugfs capabilities to netback. There used to be a similar patch floating around for classic kernel, but it used procfs. It is based on a very similar blkback patch. It creates xen-netback/[vifname]/io_ring_q[queueno] files, reading them output various ring variables etc. Writing "kick" into it imitates an interrupt happened, it can be useful to check whether the ring is just stalled due to a missed interrupt. Signed-off-by: Zoltan Kiss Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xenproject.org Signed-off-by: David S. Miller --- drivers/net/xen-netback/common.h | 11 ++ drivers/net/xen-netback/interface.c | 2 +- drivers/net/xen-netback/netback.c | 11 ++ drivers/net/xen-netback/xenbus.c | 178 +++++++++++++++++++++++++++- 4 files changed, 200 insertions(+), 2 deletions(-) diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 2532ce85d718..28c98229e95f 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -44,6 +44,7 @@ #include #include #include +#include typedef unsigned int pending_ring_idx_t; #define INVALID_PENDING_RING_IDX (~0U) @@ -224,6 +225,10 @@ struct xenvif { struct xenvif_queue *queues; unsigned int num_queues; /* active queues, resource allocated */ +#ifdef CONFIG_DEBUG_FS + struct dentry *xenvif_dbg_root; +#endif + /* Miscellaneous private stuff. */ struct net_device *dev; }; @@ -297,10 +302,16 @@ static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue) /* Callback from stack when TX packet can be released */ void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success); +irqreturn_t xenvif_interrupt(int irq, void *dev_id); + extern bool separate_tx_rx_irq; extern unsigned int rx_drain_timeout_msecs; extern unsigned int rx_drain_timeout_jiffies; extern unsigned int xenvif_max_queues; +#ifdef CONFIG_DEBUG_FS +extern struct dentry *xen_netback_dbg_root; +#endif + #endif /* __XEN_NETBACK__COMMON_H__ */ diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 9e97c7ca0ddd..ef75b45e5085 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -102,7 +102,7 @@ static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } -static irqreturn_t xenvif_interrupt(int irq, void *dev_id) +irqreturn_t xenvif_interrupt(int irq, void *dev_id) { xenvif_tx_interrupt(irq, dev_id); xenvif_rx_interrupt(irq, dev_id); diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 1844a47636b6..77127ca08ca4 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1987,6 +1987,13 @@ static int __init netback_init(void) rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs); +#ifdef CONFIG_DEBUG_FS + xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL); + if (IS_ERR_OR_NULL(xen_netback_dbg_root)) + pr_warn("Init of debugfs returned %ld!\n", + PTR_ERR(xen_netback_dbg_root)); +#endif /* CONFIG_DEBUG_FS */ + return 0; failed_init: @@ -1997,6 +2004,10 @@ module_init(netback_init); static void __exit netback_fini(void) { +#ifdef CONFIG_DEBUG_FS + if (!IS_ERR_OR_NULL(xen_netback_dbg_root)) + debugfs_remove_recursive(xen_netback_dbg_root); +#endif /* CONFIG_DEBUG_FS */ xenvif_xenbus_fini(); } module_exit(netback_fini); diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 3d85acd84bad..580517d857bf 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -44,6 +44,175 @@ static void unregister_hotplug_status_watch(struct backend_info *be); static void set_backend_state(struct backend_info *be, enum xenbus_state state); +#ifdef CONFIG_DEBUG_FS +struct dentry *xen_netback_dbg_root = NULL; + +static int xenvif_read_io_ring(struct seq_file *m, void *v) +{ + struct xenvif_queue *queue = m->private; + struct xen_netif_tx_back_ring *tx_ring = &queue->tx; + struct xen_netif_rx_back_ring *rx_ring = &queue->rx; + + if (tx_ring->sring) { + struct xen_netif_tx_sring *sring = tx_ring->sring; + + seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id, + tx_ring->nr_ents); + seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n", + sring->req_prod, + sring->req_prod - sring->rsp_prod, + tx_ring->req_cons, + tx_ring->req_cons - sring->rsp_prod, + sring->req_event, + sring->req_event - sring->rsp_prod); + seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n", + sring->rsp_prod, + tx_ring->rsp_prod_pvt, + tx_ring->rsp_prod_pvt - sring->rsp_prod, + sring->rsp_event, + sring->rsp_event - sring->rsp_prod); + seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n", + queue->pending_prod, + queue->pending_cons, + nr_pending_reqs(queue)); + seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n", + queue->dealloc_prod, + queue->dealloc_cons, + queue->dealloc_prod - queue->dealloc_cons); + } + + if (rx_ring->sring) { + struct xen_netif_rx_sring *sring = rx_ring->sring; + + seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents); + seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n", + sring->req_prod, + sring->req_prod - sring->rsp_prod, + rx_ring->req_cons, + rx_ring->req_cons - sring->rsp_prod, + sring->req_event, + sring->req_event - sring->rsp_prod); + seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n", + sring->rsp_prod, + rx_ring->rsp_prod_pvt, + rx_ring->rsp_prod_pvt - sring->rsp_prod, + sring->rsp_event, + sring->rsp_event - sring->rsp_prod); + } + + seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n" + "Credit timer_pending: %d, credit: %lu, usec: %lu\n" + "remaining: %lu, expires: %lu, now: %lu\n", + queue->napi.state, queue->napi.weight, + skb_queue_len(&queue->tx_queue), + timer_pending(&queue->credit_timeout), + queue->credit_bytes, + queue->credit_usec, + queue->remaining_credit, + queue->credit_timeout.expires, + jiffies); + + return 0; +} + +#define XENVIF_KICK_STR "kick" + +static ssize_t +xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count, + loff_t *ppos) +{ + struct xenvif_queue *queue = + ((struct seq_file *)filp->private_data)->private; + int len; + char write[sizeof(XENVIF_KICK_STR)]; + + /* don't allow partial writes and check the length */ + if (*ppos != 0) + return 0; + if (count < sizeof(XENVIF_KICK_STR) - 1) + return -ENOSPC; + + len = simple_write_to_buffer(write, + sizeof(write), + ppos, + buf, + count); + if (len < 0) + return len; + + if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1)) + xenvif_interrupt(0, (void *)queue); + else { + pr_warn("Unknown command to io_ring_q%d. Available: kick\n", + queue->id); + count = -EINVAL; + } + return count; +} + +static int xenvif_dump_open(struct inode *inode, struct file *filp) +{ + int ret; + void *queue = NULL; + + if (inode->i_private) + queue = inode->i_private; + ret = single_open(filp, xenvif_read_io_ring, queue); + filp->f_mode |= FMODE_PWRITE; + return ret; +} + +static const struct file_operations xenvif_dbg_io_ring_ops_fops = { + .owner = THIS_MODULE, + .open = xenvif_dump_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .write = xenvif_write_io_ring, +}; + +static void xenvif_debugfs_addif(struct xenvif_queue *queue) +{ + struct dentry *pfile; + struct xenvif *vif = queue->vif; + int i; + + if (IS_ERR_OR_NULL(xen_netback_dbg_root)) + return; + + vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name, + xen_netback_dbg_root); + if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) { + for (i = 0; i < vif->num_queues; ++i) { + char filename[sizeof("io_ring_q") + 4]; + + snprintf(filename, sizeof(filename), "io_ring_q%d", i); + pfile = debugfs_create_file(filename, + S_IRUSR | S_IWUSR, + vif->xenvif_dbg_root, + &vif->queues[i], + &xenvif_dbg_io_ring_ops_fops); + if (IS_ERR_OR_NULL(pfile)) + pr_warn("Creation of io_ring file returned %ld!\n", + PTR_ERR(pfile)); + } + } else + netdev_warn(vif->dev, + "Creation of vif debugfs dir returned %ld!\n", + PTR_ERR(vif->xenvif_dbg_root)); +} + +static void xenvif_debugfs_delif(struct xenvif *vif) +{ + if (IS_ERR_OR_NULL(xen_netback_dbg_root)) + return; + + if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) + debugfs_remove_recursive(vif->xenvif_dbg_root); + vif->xenvif_dbg_root = NULL; +} +#endif /* CONFIG_DEBUG_FS */ + static int netback_remove(struct xenbus_device *dev) { struct backend_info *be = dev_get_drvdata(&dev->dev); @@ -246,8 +415,12 @@ static void backend_create_xenvif(struct backend_info *be) static void backend_disconnect(struct backend_info *be) { - if (be->vif) + if (be->vif) { +#ifdef CONFIG_DEBUG_FS + xenvif_debugfs_delif(be->vif); +#endif /* CONFIG_DEBUG_FS */ xenvif_disconnect(be->vif); + } } static void backend_connect(struct backend_info *be) @@ -560,6 +733,9 @@ static void connect(struct backend_info *be) be->vif->num_queues = queue_index; goto err; } +#ifdef CONFIG_DEBUG_FS + xenvif_debugfs_addif(queue); +#endif /* CONFIG_DEBUG_FS */ } /* Initialisation completed, tell core driver the number of -- 2.30.2