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>
diff --git a/drivers/block/drbd/drbd_debugfs.c b/drivers/block/drbd/drbd_debugfs.c
index 12d072d..230d9e1 100644
--- a/drivers/block/drbd/drbd_debugfs.c
+++ b/drivers/block/drbd/drbd_debugfs.c
@@ -521,6 +521,77 @@
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 @@
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:
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 30ed430..1a00001 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -697,6 +697,15 @@
cpumask_var_t cpu_mask;
};
+struct drbd_thread_timing_details
+{
+ unsigned long start_jif;
+ void *cb_addr;
+ const char *caller_fn;
+ unsigned int line;
+ unsigned int cb_nr;
+};
+
struct drbd_connection {
struct list_head connections;
struct drbd_resource *resource;
@@ -759,6 +768,12 @@
/* sender side */
struct drbd_work_queue sender_work;
+#define DRBD_THREAD_DETAILS_HIST 16
+ unsigned int w_cb_nr; /* keeps counting up */
+ unsigned int r_cb_nr; /* keeps counting up */
+ struct drbd_thread_timing_details w_timing_details[DRBD_THREAD_DETAILS_HIST];
+ struct drbd_thread_timing_details r_timing_details[DRBD_THREAD_DETAILS_HIST];
+
struct {
/* whether this sender thread
* has processed a single write yet. */
@@ -774,6 +789,17 @@
} send;
};
+void __update_timing_details(
+ struct drbd_thread_timing_details *tdp,
+ unsigned int *cb_nr,
+ void *cb,
+ const char *fn, const unsigned int line);
+
+#define update_worker_timing_details(c, cb) \
+ __update_timing_details(c->w_timing_details, &c->w_cb_nr, cb, __func__ , __LINE__ )
+#define update_receiver_timing_details(c, cb) \
+ __update_timing_details(c->r_timing_details, &c->r_cb_nr, cb, __func__ , __LINE__ )
+
struct submit_worker {
struct workqueue_struct *wq;
struct work_struct worker;
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 9f6ed24..f972988 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2682,9 +2682,11 @@
list_add_tail(&peer_req->w.list, &device->read_ee);
spin_unlock_irq(&device->resource->req_lock);
+ update_receiver_timing_details(connection, drbd_rs_should_slow_down);
if (device->state.peer != R_PRIMARY
&& drbd_rs_should_slow_down(device, sector, false))
schedule_timeout_uninterruptible(HZ/10);
+ update_receiver_timing_details(connection, drbd_rs_begin_io);
if (drbd_rs_begin_io(device, sector))
goto out_free_e;
@@ -2692,6 +2694,7 @@
atomic_add(size >> 9, &device->rs_sect_ev);
submit:
+ update_receiver_timing_details(connection, drbd_submit_peer_request);
inc_unacked(device);
if (drbd_submit_peer_request(device, peer_req, READ, fault_type) == 0)
return 0;
@@ -4601,6 +4604,7 @@
struct data_cmd *cmd;
drbd_thread_current_set_cpu(&connection->receiver);
+ update_receiver_timing_details(connection, drbd_recv_header);
if (drbd_recv_header(connection, &pi))
goto err_out;
@@ -4619,12 +4623,14 @@
}
if (shs) {
+ update_receiver_timing_details(connection, drbd_recv_all_warn);
err = drbd_recv_all_warn(connection, pi.data, shs);
if (err)
goto err_out;
pi.size -= shs;
}
+ update_receiver_timing_details(connection, cmd->fn);
err = cmd->fn(connection, &pi);
if (err) {
drbd_err(connection, "error receiving %s, e: %d l: %d!\n",
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index b908e9b..50776b3 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1905,6 +1905,29 @@
return 0;
}
+/* only called from drbd_worker thread, no locking */
+void __update_timing_details(
+ struct drbd_thread_timing_details *tdp,
+ unsigned int *cb_nr,
+ void *cb,
+ const char *fn, const unsigned int line)
+{
+ unsigned int i = *cb_nr % DRBD_THREAD_DETAILS_HIST;
+ struct drbd_thread_timing_details *td = tdp + i;
+
+ td->start_jif = jiffies;
+ td->cb_addr = cb;
+ td->caller_fn = fn;
+ td->line = line;
+ td->cb_nr = *cb_nr;
+
+ i = (i+1) % DRBD_THREAD_DETAILS_HIST;
+ td = tdp + i;
+ memset(td, 0, sizeof(*td));
+
+ ++(*cb_nr);
+}
+
#define WORK_PENDING(work_bit, todo) (todo & (1UL << work_bit))
static void do_device_work(struct drbd_device *device, const unsigned long todo)
{
@@ -2076,11 +2099,15 @@
while (get_t_state(thi) == RUNNING) {
drbd_thread_current_set_cpu(thi);
- if (list_empty(&work_list))
+ if (list_empty(&work_list)) {
+ update_worker_timing_details(connection, wait_for_work);
wait_for_work(connection, &work_list);
+ }
- if (test_and_clear_bit(DEVICE_WORK_PENDING, &connection->flags))
+ if (test_and_clear_bit(DEVICE_WORK_PENDING, &connection->flags)) {
+ update_worker_timing_details(connection, do_unqueued_work);
do_unqueued_work(connection);
+ }
if (signal_pending(current)) {
flush_signals(current);
@@ -2097,6 +2124,7 @@
while (!list_empty(&work_list)) {
w = list_first_entry(&work_list, struct drbd_work, list);
list_del_init(&w->list);
+ update_worker_timing_details(connection, w->cb);
if (w->cb(w, connection->cstate < C_WF_REPORT_PARAMS) == 0)
continue;
if (connection->cstate >= C_WF_REPORT_PARAMS)
@@ -2105,11 +2133,14 @@
}
do {
- if (test_and_clear_bit(DEVICE_WORK_PENDING, &connection->flags))
+ if (test_and_clear_bit(DEVICE_WORK_PENDING, &connection->flags)) {
+ update_worker_timing_details(connection, do_unqueued_work);
do_unqueued_work(connection);
+ }
while (!list_empty(&work_list)) {
w = list_first_entry(&work_list, struct drbd_work, list);
list_del_init(&w->list);
+ update_worker_timing_details(connection, w->cb);
w->cb(w, 1);
}
dequeue_work_batch(&connection->sender_work, &work_list);
