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Date:   Thu, 18 Aug 2022 13:24:49 +0800
From:   Ming Lei <ming.lei@redhat.com>
To:     Chris Murphy <lists@colorremedies.com>
Cc:     Nikolay Borisov <nborisov@suse.com>, Jens Axboe <axboe@kernel.dk>,
        Jan Kara <jack@suse.cz>,
        Paolo Valente <paolo.valente@linaro.org>,
        Btrfs BTRFS <linux-btrfs@vger.kernel.org>,
        Linux-RAID <linux-raid@vger.kernel.org>,
        linux-block <linux-block@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Josef Bacik <josef@toxicpanda.com>
Subject: Re: stalling IO regression since linux 5.12, through 5.18
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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);


Thanks,
Ming