[v3,3/4] blk-mq-debugfs: Show busy requests
diff mbox

Message ID 20170601155513.26712-4-bart.vanassche@sandisk.com
State New
Headers show

Commit Message

Bart Van Assche June 1, 2017, 3:55 p.m. UTC
Requests that got stuck in a block driver are neither on
blk_mq_ctx.rq_list nor on any hw dispatch queue. Make these
visible in debugfs through the "busy" attribute.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
---
 block/blk-mq-debugfs.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

Comments

Ming Lei June 2, 2017, 2:07 a.m. UTC | #1
On Thu, Jun 01, 2017 at 08:55:12AM -0700, Bart Van Assche wrote:
> Requests that got stuck in a block driver are neither on
> blk_mq_ctx.rq_list nor on any hw dispatch queue. Make these
> visible in debugfs through the "busy" attribute.
> 
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Omar Sandoval <osandov@fb.com>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Eduardo Valentin <eduval@amazon.com>
> ---
>  block/blk-mq-debugfs.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index 8b06a12c1461..90c454bbaf92 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -370,6 +370,36 @@ static const struct seq_operations hctx_dispatch_seq_ops = {
>  	.show	= blk_mq_debugfs_rq_show,
>  };
>  
> +struct show_busy_params {
> +	struct seq_file		*m;
> +	struct blk_mq_hw_ctx	*hctx;
> +};
> +
> +/*
> + * Note: the state of a request may change while this function is in progress,
> + * e.g. due to a concurrent blk_mq_finish_request() call.
> + */
> +static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
> +{
> +	const struct show_busy_params *params = data;
> +
> +	if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == params->hctx &&
> +	    test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
> +		__blk_mq_debugfs_rq_show(params->m,
> +					 list_entry_rq(&rq->queuelist));
> +}
> +
> +static int hctx_busy_show(void *data, struct seq_file *m)
> +{
> +	struct blk_mq_hw_ctx *hctx = data;
> +	struct show_busy_params params = { .m = m, .hctx = hctx };
> +
> +	blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
> +				&params);
> +
> +	return 0;
> +}
> +
>  static int hctx_ctx_map_show(void *data, struct seq_file *m)
>  {
>  	struct blk_mq_hw_ctx *hctx = data;
> @@ -705,6 +735,7 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
>  	{"state", 0400, hctx_state_show},
>  	{"flags", 0400, hctx_flags_show},
>  	{"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
> +	{"busy", 0400, hctx_busy_show},
>  	{"ctx_map", 0400, hctx_ctx_map_show},
>  	{"tags", 0400, hctx_tags_show},
>  	{"tags_bitmap", 0400, hctx_tags_bitmap_show},
> -- 
> 2.12.2
> 

Reviewed-by: Ming Lei <ming.lei@redhat.com>

Thanks,
Ming

Patch
diff mbox

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 8b06a12c1461..90c454bbaf92 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -370,6 +370,36 @@  static const struct seq_operations hctx_dispatch_seq_ops = {
 	.show	= blk_mq_debugfs_rq_show,
 };
 
+struct show_busy_params {
+	struct seq_file		*m;
+	struct blk_mq_hw_ctx	*hctx;
+};
+
+/*
+ * Note: the state of a request may change while this function is in progress,
+ * e.g. due to a concurrent blk_mq_finish_request() call.
+ */
+static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
+{
+	const struct show_busy_params *params = data;
+
+	if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == params->hctx &&
+	    test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
+		__blk_mq_debugfs_rq_show(params->m,
+					 list_entry_rq(&rq->queuelist));
+}
+
+static int hctx_busy_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+	struct show_busy_params params = { .m = m, .hctx = hctx };
+
+	blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
+				&params);
+
+	return 0;
+}
+
 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 {
 	struct blk_mq_hw_ctx *hctx = data;
@@ -705,6 +735,7 @@  static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 	{"state", 0400, hctx_state_show},
 	{"flags", 0400, hctx_flags_show},
 	{"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
+	{"busy", 0400, hctx_busy_show},
 	{"ctx_map", 0400, hctx_ctx_map_show},
 	{"tags", 0400, hctx_tags_show},
 	{"tags_bitmap", 0400, hctx_tags_bitmap_show},