On 05/26/2017 01:38 AM, 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 <[email protected]> > Cc: Christoph Hellwig <[email protected]> > Cc: Hannes Reinecke <[email protected]> > Cc: Omar Sandoval <[email protected]> > Cc: Ming Lei <[email protected]> > --- > block/blk-mq-debugfs.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c > index 8b06a12c1461..70a2b955afee 100644 > --- a/block/blk-mq-debugfs.c > +++ b/block/blk-mq-debugfs.c > @@ -370,6 +370,30 @@ static const struct seq_operations hctx_dispatch_seq_ops > = { > .show = blk_mq_debugfs_rq_show, > }; > > +struct show_busy_ctx { > + 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_ctx *ctx = data; > + > + if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == ctx->hctx && > + test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) > + blk_mq_debugfs_rq_show(ctx->m, &rq->queuelist); > +} > + > +static int hctx_busy_show(void *data, struct seq_file *m) > +{ > + struct blk_mq_hw_ctx *hctx = data; > + struct show_busy_ctx ctx = { .m = m, .hctx = hctx }; > + > + blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy, &ctx); > + > + return 0; > +} > + > static int hctx_ctx_map_show(void *data, struct seq_file *m) > { > struct blk_mq_hw_ctx *hctx = data; > @@ -705,6 +729,7 @@ 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}, > Hmm. I wonder if this is going to work as intended; 'busy' might be changing rapidly, so the busy_iter might be giving us unintended results. Have you checked?
Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
