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Commit 2720bab5 authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

blk-mq-debugfs: Show busy requests 



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: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: default avatarEduardo Valentin <eduval@amazon.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>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 8ef1a191

block/blk-mq-debugfs.c

+31 −0
Original line number Diff line number Diff line
@@ -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},