On 08/22/18 21:17, Jens Axboe wrote:

quoted

So the obvious suspect is the new return of UINT_MAX from get_limit() to
__wbt_wait(). I first suspected that I mispatched something, but it's all
like in mainline or your tree. Even the recently moved-around atomic loop
inside rq_wait_inc_below() is 1:1 the same and looks like it should.
Now building mainline and see where that leads me.

So mainline + your tree's last 4 patches works fine, as suspected.
It's all me, as usual.

I wonder if it's a signedness thing? Can you try and see if using INT_MAX
instead changes anything?

Beat me to it while I was rebooting ;-)
Exactly what I also found a minute ago:

$diff -rup linux-4.18.4/block/blk-rq-qos.c linux/block/blk-rq-qos.c
..
-bool rq_wait_inc_below(struct rq_wait *rq_wait, int limit)
+bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit)
..

Moo! Patching now.

cheers
Holger