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blk-mq-debugfs: Show busy requests

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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@sandisk.com>
Reviewed-by: Eduardo 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: Jens Axboe <axboe@fb.com>
This commit is contained in:
Bart Van Assche 2017-06-01 08:55:12 -07:00 committed by Jens Axboe
parent 8ef1a19103
commit 2720bab502
1 changed files with 31 additions and 0 deletions
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31
block/blk-mq-debugfs.c
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@ -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},