On Wed, May 31, 2017 at 02:30:49PM -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>
> ---
> block/blk-mq-debugfs.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index 8b06a12c1461..fa0f624dfccd 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -370,6 +370,31 @@ 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;
> +};
> +
> +static void hctx_show_busy(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));
> +}
Not like dumping requests in ctx and requeue list, the dumped requests
here may have been released and the result may not be 100% reliable,
so suggest to add comment for this fact.
Otherwise, looks fine for me.
Thanks,
Ming
