Re: [PATCH V6 0/3] blk-mq: fix blk_mq_alloc_request_hctx

On Thu, Jul 22, 2021 at 10:06:51PM +0000, Wen Xiong wrote:

   > Wen Xiong has verified V4 in her nvmef test.

   >>FWIW, I am testing this series right now. I observe hanging I/Os
   >>again, but I am not totally sure if my test setup is working
   >>properly. Working on it. I'll keep you posted.
    

 I built the latest upstream(v5.14-rc2) + Ming's V6 + Daniel's V3: didn't work.

Hi Wenxiong,

V6 is basically same with V4, can you figure out where the failure
comes?(v5.14-rc2, V6 or Daniel's V3) 

I verified that V6 works as expected by tracing blk_mq_update_queue_map():

#!/usr/bin/bpftrace
#include <linux/blk-mq.h>
kprobe:blk_mq_update_queue_map
{
	@in_map[tid]=1;
	@set[tid] = (struct blk_mq_tag_set *)arg0;
	@ms[tid] = kstack;
}

kretprobe:blk_mq_update_queue_map
/@in_map[tid]==1/
{
	$s = @set[tid];
	$m = (struct blk_mq_queue_map *)$s->map;

	printf("%s %d: %s queues %d use_managed_irq %d\n",
		comm, pid, @ms[tid], $s->nr_hw_queues, $m->use_managed_irq);
}


Thanks,
Ming