On 5/13/23 8:12 AM, Tian Lan wrote: > From: Tian Lan <tian.lan@xxxxxxxxxxxx> > > The nr_active counter continues to increase over time which causes the > blk_mq_get_tag to hang until the thread is rescheduled to a different > core despite there are still tags available. > > kernel-stack > > INFO: task inboundIOReacto:3014879 blocked for more than 2 seconds > Not tainted 6.1.15-amd64 #1 Debian 6.1.15~debian11 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:inboundIOReacto state:D stack:0 pid:3014879 ppid:4557 flags:0x00000000 > Call Trace: > <TASK> > __schedule+0x351/0xa20 > scheduler+0x5d/0xe0 > io_schedule+0x42/0x70 > blk_mq_get_tag+0x11a/0x2a0 > ? dequeue_task_stop+0x70/0x70 > __blk_mq_alloc_requests+0x191/0x2e0 > > kprobe output showing RQF_MQ_INFLIGHT bit is not cleared before > __blk_mq_free_request being called. > > 320 320 kworker/29:1H __blk_mq_free_request rq_flags 0x220c0 in-flight 1 > b'__blk_mq_free_request+0x1 [kernel]' > b'bt_iter+0x50 [kernel]' > b'blk_mq_queue_tag_busy_iter+0x318 [kernel]' > b'blk_mq_timeout_work+0x7c [kernel]' > b'process_one_work+0x1c4 [kernel]' > b'worker_thread+0x4d [kernel]' > b'kthread+0xe6 [kernel]' > b'ret_from_fork+0x1f [kernel]' > > Signed-off-by: Tian Lan <tian.lan@xxxxxxxxxxxx> > --- > block/blk-mq.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 9c8dc70020bc..5b374fab169c 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1593,6 +1593,9 @@ void blk_mq_put_rq_ref(struct request *rq) > if (rq->end_io(rq, 0) == RQ_END_IO_FREE) > blk_mq_free_request(rq); > } else if (req_ref_put_and_test(rq)) { > + if (rq->rq_flags & RQF_MQ_INFLIGHT) > + __blk_mq_dec_active_requests(rq->mq_hctx) > + > __blk_mq_free_request(rq); > } > } The fact that you didn't even compile this not withstanding, why not just move the existing check from blk_mq_free_request() to __blk_mq_free_request()? -- Jens Axboe