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 <zoltan.kiss@citrix.com> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xenproject.org Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Zoltan Kiss
committed by
David S. Miller
David S. Miller
parent
a37934fc0d
commit
f51de24356
@@ -44,6 +44,175 @@ static void unregister_hotplug_status_watch(struct backend_info *be);
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static void set_backend_state(struct backend_info *be,
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enum xenbus_state state);
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#ifdef CONFIG_DEBUG_FS
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struct dentry *xen_netback_dbg_root = NULL;
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static int xenvif_read_io_ring(struct seq_file *m, void *v)
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{
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struct xenvif_queue *queue = m->private;
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struct xen_netif_tx_back_ring *tx_ring = &queue->tx;
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struct xen_netif_rx_back_ring *rx_ring = &queue->rx;
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if (tx_ring->sring) {
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struct xen_netif_tx_sring *sring = tx_ring->sring;
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seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id,
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tx_ring->nr_ents);
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seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
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sring->req_prod,
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sring->req_prod - sring->rsp_prod,
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tx_ring->req_cons,
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tx_ring->req_cons - sring->rsp_prod,
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sring->req_event,
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sring->req_event - sring->rsp_prod);
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seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n",
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sring->rsp_prod,
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tx_ring->rsp_prod_pvt,
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tx_ring->rsp_prod_pvt - sring->rsp_prod,
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sring->rsp_event,
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sring->rsp_event - sring->rsp_prod);
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seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n",
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queue->pending_prod,
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queue->pending_cons,
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nr_pending_reqs(queue));
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seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n",
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queue->dealloc_prod,
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queue->dealloc_cons,
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queue->dealloc_prod - queue->dealloc_cons);
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}
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if (rx_ring->sring) {
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struct xen_netif_rx_sring *sring = rx_ring->sring;
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seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents);
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seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
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sring->req_prod,
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sring->req_prod - sring->rsp_prod,
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rx_ring->req_cons,
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rx_ring->req_cons - sring->rsp_prod,
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sring->req_event,
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sring->req_event - sring->rsp_prod);
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seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n",
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sring->rsp_prod,
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rx_ring->rsp_prod_pvt,
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rx_ring->rsp_prod_pvt - sring->rsp_prod,
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sring->rsp_event,
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sring->rsp_event - sring->rsp_prod);
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}
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seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n"
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"Credit timer_pending: %d, credit: %lu, usec: %lu\n"
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"remaining: %lu, expires: %lu, now: %lu\n",
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queue->napi.state, queue->napi.weight,
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skb_queue_len(&queue->tx_queue),
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timer_pending(&queue->credit_timeout),
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queue->credit_bytes,
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queue->credit_usec,
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queue->remaining_credit,
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queue->credit_timeout.expires,
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jiffies);
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return 0;
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}
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#define XENVIF_KICK_STR "kick"
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static ssize_t
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xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count,
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loff_t *ppos)
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{
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struct xenvif_queue *queue =
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((struct seq_file *)filp->private_data)->private;
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int len;
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char write[sizeof(XENVIF_KICK_STR)];
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/* don't allow partial writes and check the length */
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if (*ppos != 0)
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return 0;
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if (count < sizeof(XENVIF_KICK_STR) - 1)
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return -ENOSPC;
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len = simple_write_to_buffer(write,
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sizeof(write),
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ppos,
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buf,
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count);
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if (len < 0)
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return len;
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if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1))
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xenvif_interrupt(0, (void *)queue);
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else {
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pr_warn("Unknown command to io_ring_q%d. Available: kick\n",
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queue->id);
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count = -EINVAL;
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}
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return count;
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}
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static int xenvif_dump_open(struct inode *inode, struct file *filp)
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{
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int ret;
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void *queue = NULL;
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if (inode->i_private)
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queue = inode->i_private;
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ret = single_open(filp, xenvif_read_io_ring, queue);
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filp->f_mode |= FMODE_PWRITE;
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return ret;
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}
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static const struct file_operations xenvif_dbg_io_ring_ops_fops = {
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.owner = THIS_MODULE,
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.open = xenvif_dump_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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.write = xenvif_write_io_ring,
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};
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static void xenvif_debugfs_addif(struct xenvif_queue *queue)
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{
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struct dentry *pfile;
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struct xenvif *vif = queue->vif;
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int i;
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if (IS_ERR_OR_NULL(xen_netback_dbg_root))
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return;
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vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
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xen_netback_dbg_root);
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if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) {
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for (i = 0; i < vif->num_queues; ++i) {
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char filename[sizeof("io_ring_q") + 4];
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snprintf(filename, sizeof(filename), "io_ring_q%d", i);
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pfile = debugfs_create_file(filename,
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S_IRUSR | S_IWUSR,
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vif->xenvif_dbg_root,
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&vif->queues[i],
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&xenvif_dbg_io_ring_ops_fops);
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if (IS_ERR_OR_NULL(pfile))
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pr_warn("Creation of io_ring file returned %ld!\n",
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PTR_ERR(pfile));
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}
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} else
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netdev_warn(vif->dev,
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"Creation of vif debugfs dir returned %ld!\n",
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PTR_ERR(vif->xenvif_dbg_root));
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}
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static void xenvif_debugfs_delif(struct xenvif *vif)
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{
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if (IS_ERR_OR_NULL(xen_netback_dbg_root))
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return;
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if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root))
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debugfs_remove_recursive(vif->xenvif_dbg_root);
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vif->xenvif_dbg_root = NULL;
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}
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#endif /* CONFIG_DEBUG_FS */
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static int netback_remove(struct xenbus_device *dev)
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{
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struct backend_info *be = dev_get_drvdata(&dev->dev);
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@@ -246,8 +415,12 @@ static void backend_create_xenvif(struct backend_info *be)
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static void backend_disconnect(struct backend_info *be)
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{
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if (be->vif)
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if (be->vif) {
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#ifdef CONFIG_DEBUG_FS
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xenvif_debugfs_delif(be->vif);
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#endif /* CONFIG_DEBUG_FS */
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xenvif_disconnect(be->vif);
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}
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}
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static void backend_connect(struct backend_info *be)
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@@ -560,6 +733,9 @@ static void connect(struct backend_info *be)
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be->vif->num_queues = queue_index;
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goto err;
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}
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#ifdef CONFIG_DEBUG_FS
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xenvif_debugfs_addif(queue);
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#endif /* CONFIG_DEBUG_FS */
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}
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/* Initialisation completed, tell core driver the number of
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