Re: [PATCH 1/2] generic: fsstress with cpu offlining

[Zorro Lang <zlang@redhat.com>]

On Tue, Aug 17, 2021 at 04:53:19PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> Exercise filesystem operations when we're taking CPUs online and offline
> throughout the test.

Just ask, is this test cover something (commits)?

> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  tests/generic/726     |   71 +++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/726.out |    2 +
>  2 files changed, 73 insertions(+)
>  create mode 100755 tests/generic/726
>  create mode 100644 tests/generic/726.out
> 
> 
> diff --git a/tests/generic/726 b/tests/generic/726
> new file mode 100755
> index 00000000..4b072b7f
> --- /dev/null
> +++ b/tests/generic/726
> @@ -0,0 +1,71 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2021 Oracle, Inc.  All Rights Reserved.
> +#
> +# FS QA Test No. 726
> +#
> +# Run an all-writes fsstress run with multiple threads while exercising CPU
> +# hotplugging to shake out bugs in the write path.
> +#
> +. ./common/preamble
> +_begin_fstest auto rw
> +
> +# Override the default cleanup function.
> +_cleanup()
> +{
> +	cd /
> +	rm -f $tmp.*
> +	$KILLALL_PROG -9 fsstress > /dev/null 2>&1

At least there's "exercise_cpu_hotplug &", should we wait at here? Even we removed
$tmp.hotplug, can't make sure the process is over.

> +	for i in "$sysfs_cpu_dir/"cpu*/online; do
> +		echo 1 > "$i" 2>/dev/null
> +	done
> +}
> +
> +exercise_cpu_hotplug()
> +{
> +	while [ -e $sentinel_file ]; do
> +		local idx=$(( RANDOM % nr_hotplug_cpus ))
> +		local cpu="${hotplug_cpus[idx]}"
> +		local action=$(( RANDOM % 2 ))
> +
> +		echo "$action" > "$sysfs_cpu_dir/cpu$cpu/online" 2>/dev/null
> +		sleep 0.5
> +	done
> +}
> +
> +# Import common functions.
> +
> +# Modify as appropriate.

Two useless comments at here?

> +_supported_fs generic
> +
> +sysfs_cpu_dir="/sys/devices/system/cpu"
> +
> +# Figure out which CPU(s) support hotplug.
> +nrcpus=$(getconf _NPROCESSORS_CONF)
> +hotplug_cpus=()
> +for ((i = 0; i < nrcpus; i++ )); do
> +	test -e "$sysfs_cpu_dir/cpu$i/online" && hotplug_cpus+=("$i")
> +done
> +nr_hotplug_cpus="${#hotplug_cpus[@]}"
> +test "$nr_hotplug_cpus" -gt 0 || _notrun "CPU hotplugging not supported"

Is that worth being a helper?

> +
> +_require_scratch
> +_require_command "$KILLALL_PROG" "killall"
> +
> +echo "Silence is golden."
> +
> +_scratch_mkfs > $seqres.full 2>&1
> +_scratch_mount >> $seqres.full 2>&1
> +
> +sentinel_file=$tmp.hotplug
> +touch $sentinel_file
> +exercise_cpu_hotplug &
> +
> +nr_cpus=$((LOAD_FACTOR * 4))
> +nr_ops=$((10000 * nr_cpus * TIME_FACTOR))
> +$FSSTRESS_PROG $FSSTRESS_AVOID -w -d $SCRATCH_MNT -n $nr_ops -p $nr_cpus >> $seqres.full
> +rm -f $sentinel_file
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/726.out b/tests/generic/726.out
> new file mode 100644
> index 00000000..6839f8ce
> --- /dev/null
> +++ b/tests/generic/726.out
> @@ -0,0 +1,2 @@
> +QA output created by 726
> +Silence is golden.
>