From 2720bab50258782573df0f536681bece11e784f0 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 1 Jun 2017 08:55:12 -0700 Subject: [PATCH] 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: Bart Van Assche Reviewed-by: Eduardo Valentin Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei Signed-off-by: Jens Axboe --- 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}, -- 2.20.1