Re: stalling IO regression since linux 5.12, through 5.18

[Ming Lei <ming.lei@redhat.com>]

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