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authorLars Ellenberg <lars.ellenberg@linbit.com>2014-05-06 17:02:05 +0400
committerPhilipp Reisner <philipp.reisner@linbit.com>2014-07-10 20:35:18 +0400
commit944410e97cfcec38369eeb5f77d0e8da91d68afb (patch)
tree486f49038fa17542d14cda8028a9b122cf1df94a /drivers/block/drbd/drbd_debugfs.c
parentf418815f7adad4917e92e9d11fdc1ca21cd616a1 (diff)
downloadlinux-944410e97cfcec38369eeb5f77d0e8da91d68afb.tar.xz
drbd: debugfs: add callback_history
Add a per-connection worker thread callback_history with timing details, call site and callback function. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd/drbd_debugfs.c')
-rw-r--r--drivers/block/drbd/drbd_debugfs.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_debugfs.c b/drivers/block/drbd/drbd_debugfs.c
index 12d072d9751f..230d9e1fc85c 100644
--- a/drivers/block/drbd/drbd_debugfs.c
+++ b/drivers/block/drbd/drbd_debugfs.c
@@ -521,6 +521,77 @@ void drbd_debugfs_resource_cleanup(struct drbd_resource *resource)
drbd_debugfs_remove(&resource->debugfs_res);
}
+static void seq_print_one_timing_detail(struct seq_file *m,
+ const struct drbd_thread_timing_details *tdp,
+ unsigned long now)
+{
+ struct drbd_thread_timing_details td;
+ /* No locking...
+ * use temporary assignment to get at consistent data. */
+ do {
+ td = *tdp;
+ } while (td.cb_nr != tdp->cb_nr);
+ if (!td.cb_addr)
+ return;
+ seq_printf(m, "%u\t%d\t%s:%u\t%ps\n",
+ td.cb_nr,
+ jiffies_to_msecs(now - td.start_jif),
+ td.caller_fn, td.line,
+ td.cb_addr);
+}
+
+static void seq_print_timing_details(struct seq_file *m,
+ const char *title,
+ unsigned int cb_nr, struct drbd_thread_timing_details *tdp, unsigned long now)
+{
+ unsigned int start_idx;
+ unsigned int i;
+
+ seq_printf(m, "%s\n", title);
+ /* If not much is going on, this will result in natural ordering.
+ * If it is very busy, we will possibly skip events, or even see wrap
+ * arounds, which could only be avoided with locking.
+ */
+ start_idx = cb_nr % DRBD_THREAD_DETAILS_HIST;
+ for (i = start_idx; i < DRBD_THREAD_DETAILS_HIST; i++)
+ seq_print_one_timing_detail(m, tdp+i, now);
+ for (i = 0; i < start_idx; i++)
+ seq_print_one_timing_detail(m, tdp+i, now);
+}
+
+static int callback_history_show(struct seq_file *m, void *ignored)
+{
+ struct drbd_connection *connection = m->private;
+ unsigned long jif = jiffies;
+
+ seq_puts(m, "n\tage\tcallsite\tfn\n");
+ seq_print_timing_details(m, "worker", connection->w_cb_nr, connection->w_timing_details, jif);
+ seq_print_timing_details(m, "receiver", connection->r_cb_nr, connection->r_timing_details, jif);
+ return 0;
+}
+
+static int callback_history_open(struct inode *inode, struct file *file)
+{
+ struct drbd_connection *connection = inode->i_private;
+ return drbd_single_open(file, callback_history_show, connection,
+ &connection->kref, drbd_destroy_connection);
+}
+
+static int callback_history_release(struct inode *inode, struct file *file)
+{
+ struct drbd_connection *connection = inode->i_private;
+ kref_put(&connection->kref, drbd_destroy_connection);
+ return single_release(inode, file);
+}
+
+static const struct file_operations connection_callback_history_fops = {
+ .owner = THIS_MODULE,
+ .open = callback_history_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = callback_history_release,
+};
+
void drbd_debugfs_connection_add(struct drbd_connection *connection)
{
struct dentry *conns_dir = connection->resource->debugfs_res_connections;
@@ -535,6 +606,13 @@ void drbd_debugfs_connection_add(struct drbd_connection *connection)
if (IS_ERR_OR_NULL(dentry))
goto fail;
connection->debugfs_conn = dentry;
+
+ dentry = debugfs_create_file("callback_history", S_IRUSR|S_IRGRP,
+ connection->debugfs_conn, connection,
+ &connection_callback_history_fops);
+ if (IS_ERR_OR_NULL(dentry))
+ goto fail;
+ connection->debugfs_conn_callback_history = dentry;
return;
fail: