linux-kernel - Re: stalling IO regression since linux 5.12, through 5.18

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Message-Id: <0f731b0a-fbd5-4e7b-a3df-0ed63360c1e0@www.fastmail.com>
Date:   Fri, 19 Aug 2022 15:20:25 -0400
From:   "Chris Murphy" <lists@...orremedies.com>
To:     "Ming Lei" <ming.lei@...hat.com>
Cc:     "Nikolay Borisov" <nborisov@...e.com>,
        "Jens Axboe" <axboe@...nel.dk>, "Jan Kara" <jack@...e.cz>,
        "Paolo Valente" <paolo.valente@...aro.org>,
        "Btrfs BTRFS" <linux-btrfs@...r.kernel.org>,
        Linux-RAID <linux-raid@...r.kernel.org>,
        linux-block <linux-block@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "Josef Bacik" <josef@...icpanda.com>
Subject: Re: stalling IO regression since linux 5.12, through 5.18



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