Re: INFO: task hung in blk_queue_enter

From: Martin Steigerwald
Date: Sat Jun 02 2018 - 04:07:45 EST

Ming Lei - 02.06.18, 06:54:
> On Fri, Jun 01, 2018 at 10:31:13PM -0600, Jens Axboe wrote:
> > On 6/1/18 8:36 PM, Ming Lei wrote:
> > >> clear the bit when we need to, potentially even adding a debug
> > >> check to blk_queue_enter_live() that complains if the ref was
> > >> not already elevated. Though that would be expensive, compared
> > >> to the percpu inc now. Not saying the bit is necessarily the
> > >> best way forward, but I do like it a LOT more than adding an
> > >> argument to generic_make_request.> >
> > > We may introduce generic_make_request_with_ref() for
> > > blk_queue_split(), what do you think of the following patch?
> >
> > Functionally it'll work as well.
> If you are fine with this one, I'm glad to prepare for a normal one,
> so that we can save one precious bio flag, and the total number is
> just 13.

I am completely lost about what you are talking about.

That is fine with me, but in case there is anything to testâ let me
know. I do not promise quick responses tough, as I have been quite a bit
overwhelmed with stuff lately.

Currently I run 4.17-rc7 without any blk-mq related patches and it
appears to be free of hangs or stalls related to blk-mq.