On Sun, Sep 05, 2021 at 10:48:15PM +0800, Eryu Guan wrote:

On Tue, Aug 31, 2021 at 05:11:50PM -0700, Darrick J. Wong wrote:

quoted

From: Darrick J. Wong <djwong@kernel.org>

Exercise filesystem operations when we're taking CPUs online and offline
throughout the test.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 tests/generic/726     |   69 +++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/726.out |    2 +
 2 files changed, 71 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..cb709795
--- /dev/null
+++ b/tests/generic/726

@@ -0,0 +1,69 @@
+#! /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 stress
+
+# Override the default cleanup function.
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+	$KILLALL_PROG -9 fsstress > /dev/null 2>&1
+	wait	# for exercise_cpu_hotplug subprocess
+	for i in "$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$cpu/online" 2>/dev/null
+		sleep 0.5
+	done
+}
+
+_supported_fs generic
+
+sysfs_cpu_dir="/sys/devices/system/cpu"
+
+# Figure out which CPU(s) support hotplug.
+nrcpus=$(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 "$nr_hotplug_cpus" -gt 0 || _notrun "CPU hotplugging not supported"
+
+_require_scratch
+_require_command "$KILLALL_PROG" "killall"
+
+echo "Silence is golden."
+
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1

I think we could just run fsstress against a dir in $TEST_DIR?

Ok.

quoted

+
+sentinel_file=$tmp.hotplug
+touch $sentinel_file
+exercise_cpu_hotplug &
+
+nr_cpus=$((LOAD_FACTOR * nr_hotplug_cpus))

We'd better to cap nr_cpu just in case we're testing on a system with
1024 cpus and taking very long time for fsstress to finish.

Not sure why that matters, but I'll cap the number of IO thread at one
per hotpluggable CPU if we go over 1024.

--D

Thanks,
Eryu

quoted

+nr_ops=$((25000 * TIME_FACTOR))
+$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.