From: Omar Sandoval <osandov@xxxxxx>
This can be used to diagnose freeze-related hangs.
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
---
block/blk-mq-debugfs.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index f6d917977b33..1459546788da 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -29,6 +29,26 @@ struct blk_mq_debugfs_attr {
const struct file_operations *fops;
};
+static int queue_freeze_depth_show(struct seq_file *m, void *v)
+{
+ struct request_queue *q = m->private;
+
+ seq_printf(m, "%d\n", atomic_read(&q->mq_freeze_depth));
+ return 0;
+}
+
+static int queue_freeze_depth_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, queue_freeze_depth_show, inode->i_private);
+}
+
+static const struct file_operations queue_freeze_depth_fops = {
+ .open = queue_freeze_depth_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
static int blk_mq_debugfs_seq_open(struct inode *inode, struct file *file,
const struct seq_operations *ops)
{
@@ -636,6 +656,11 @@ static const struct file_operations ctx_completed_fops = {
.release = single_release,
};
+static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
+ {"freeze_depth", 0400, &queue_freeze_depth_fops},
+ {},
+};
+
static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
{"state", 0400, &hctx_state_fops},
{"flags", 0400, &hctx_flags_fops},
@@ -753,6 +778,9 @@ int blk_mq_debugfs_register_hctxs(struct request_queue *q)
if (!q->mq_debugfs_dir)
goto err;
+ if (!debugfs_create_files(q->mq_debugfs_dir, q, blk_mq_debugfs_queue_attrs))
+ return -ENOMEM;
+
queue_for_each_hw_ctx(q, hctx, i) {
if (blk_mq_debugfs_register_hctx(q, hctx))
goto err;
--
2.12.0
