Thanks,
Yi
>
> Some on-site information:
>
> >>> rwb.rq_depth.max_depth
> (unsigned int)48
> >>> rqw.inflight.counter.value_()
> 44
> >>> rqw.inflight.counter.value_()
> 35
> >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep
> (unsigned long)3
> >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep
> (unsigned long)2
> >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep
> (unsigned long)20
> >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep
> (unsigned long)12
>
> cat wb_normal
> 24
> cat wb_background
> 12
>
> To fix this issue, we can use max_depth in wbt_rqw_done(), so that
> the handling of wb_recent_wait by wbt_rqw_done() and get_limit()
> will also be consistent, which is more reasonable.
>
> Signed-off-by: Julian Sun <sunjunchao@xxxxxxxxxxxxx>
> Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism")
> ---
> block/blk-wbt.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/block/blk-wbt.c b/block/blk-wbt.c
> index a50d4cd55f41..d6a2782d442f 100644
> --- a/block/blk-wbt.c
> +++ b/block/blk-wbt.c
> @@ -210,6 +210,8 @@ static void wbt_rqw_done(struct rq_wb *rwb, struct rq_wait *rqw,
> else if (blk_queue_write_cache(rwb->rqos.disk->queue) &&
> !wb_recent_wait(rwb))
> limit = 0;
> + else if (wb_recent_wait(rwb))
> + limit = rwb->rq_depth.max_depth;
> else
> limit = rwb->wb_normal;
>
> --
> 2.20.1
>
>
