Re: [PATCH] block: fix fio jobs for 027 and add cgroup support

[Omar Sandoval <osandov@osandov.com>]

On Fri, Mar 29, 2019 at 03:14:32PM -0700, Dennis Zhou wrote:
> Previously, the test was broken as "$fio_jobs" was considered as a
> string instead of additional parameters. This is fixed here.
> 
> Second, there was an issue with earlier kernels when request lists
> existed such that request_queues were never being cleaned up because
> non-root blkgs took a reference on the queue. However, blkgs were being
> cleaned up after the last reference to the request_queue was put back.
> This creates a blktest cgroup for the fio jobs to utilize and should be
> useful for catching this scenario in the future.
> 
> Signed-off-by: Dennis Zhou <dennis@kernel.org>

Would it be valuable to test this both in a cgroup and not in a cgroup?

>  tests/block/027 | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/block/027 b/tests/block/027
> index b480016..36e88b4 100755
> --- a/tests/block/027
> +++ b/tests/block/027
> @@ -26,6 +26,13 @@ scsi_debug_stress_remove() {
>  		return
>  	fi
>  
> +	_init_cgroup2
> +
> +	# setup cgroups
> +	echo "+io" > "/sys/fs/cgroup/cgroup.subtree_control"
> +	echo "+io" > "$CGROUP2_DIR/cgroup.subtree_control"
> +	mkdir "$CGROUP2_DIR/fast"
> +

Why is this called "fast"?

>  	# set higher aio limit
>  	echo 524288 > /proc/sys/fs/aio-max-nr
>  
> @@ -45,13 +52,13 @@ scsi_debug_stress_remove() {
>  		((cnt++))
>  	done
>  
> -	local num_jobs=4 runtime=21
> +	local num_jobs=4 runtime=12
>  	fio --rw=randread --size=128G --direct=1 --ioengine=libaio \
>  		--iodepth=2048 --numjobs=$num_jobs --bs=4k \
>  		--group_reporting=1 --group_reporting=1 --runtime=$runtime \
> -		--loops=10000 "$fio_jobs" > "$FULL" 2>&1 &
> +		--loops=10000 --cgroup=blktests/fast $fio_jobs > "$FULL" 2>&1 &
>  
> -	sleep 7
> +	sleep 6

Is there any particular reason you changed the run time and sleep time
and added the sleep at the end?

>  	local device_path
>  	for dev in "${SCSI_DEBUG_DEVICES[@]}"; do
>  		# shutdown devices in progress
> @@ -61,6 +68,10 @@ scsi_debug_stress_remove() {
>  
>  	wait
>  
> +	sleep 10
> +
> +	_exit_cgroup2
> +
>  	_exit_scsi_debug
>  }
>  
> -- 
> 2.17.1
>