Re: stalling IO regression since linux 5.12, through 5.18

[Chris Murphy]

On Thu, Aug 18, 2022, at 1:24 AM, Ming Lei wrote:
> On Thu, Aug 18, 2022 at 12:27:04AM -0400, Chris Murphy wrote:
>> 
>> 
>> On Thu, Aug 18, 2022, at 12:18 AM, Chris Murphy wrote:
>> > On Thu, Aug 18, 2022, at 12:12 AM, Chris Murphy wrote:
>> >> On Wed, Aug 17, 2022, at 11:41 PM, Ming Lei wrote:
>> >>
>> >>> OK, can you post the blk-mq debugfs log after you trigger it on v5.17?
>> 
>> Same boot, 3rd log. But the load is above 300 so I kinda need to sysrq+b soon.
>> 
>> https://drive.google.com/file/d/1375H558kqPTdng439rvG6LuXXWPXLToo/view?usp=sharing
>> 
>
> Also please test the following one too:
>
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 5ee62b95f3e5..d01c64be08e2 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1991,7 +1991,8 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx 
> *hctx, struct list_head *list,
>  		if (!needs_restart ||
>  		    (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
>  			blk_mq_run_hw_queue(hctx, true);
> -		else if (needs_restart && needs_resource)
> +		else if (needs_restart && (needs_resource ||
> +					blk_mq_is_shared_tags(hctx->flags)))
>  			blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
> 
>  		blk_mq_update_dispatch_busy(hctx, true);
>


With just this patch on top of 5.17.0, it still hangs. I've captured block debugfs log:
https://drive.google.com/file/d/1ic4YHxoL9RrCdy_5FNdGfh_q_J3d_Ft0/view?usp=sharing



-- 
Chris Murphy