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authorBart Van Assche <bart.vanassche@sandisk.com>2017-06-01 18:55:12 +0300
committerJens Axboe <axboe@fb.com>2017-06-01 22:02:59 +0300
commit2720bab50258782573df0f536681bece11e784f0 (patch)
tree06a2527f7094bc2da1e4fbb681db28743d6fa804 /block/blk-mq-debugfs.c
parent8ef1a191038c138d5675933cd69d47747d0d396b (diff)
downloadlinux-2720bab50258782573df0f536681bece11e784f0.tar.xz
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 <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>
Diffstat (limited to 'block/blk-mq-debugfs.c')
-rw-r--r--block/blk-mq-debugfs.c31
1 files changed, 31 insertions, 0 deletions
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,
+ &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},