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@xxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Omar Sandoval <osandov@xxxxxx>
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> Cc: Eduardo Valentin <eduval@xxxxxxxxxx>
> ---
> 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,
> + ¶ms);
> +
> + 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@xxxxxxxxxx>
Thanks,
Ming
