43 lines
1.4 KiB
Plaintext
43 lines
1.4 KiB
Plaintext
|
#!/bin/bash
|
||
|
|
# This util helps to reduce the workload of kdump service restarting
|
||
|
|
# on udev event. When hotplugging memory / CPU, multiple udev
|
||
|
|
# events may be triggered concurrently, and obviously, we don't want
|
||
|
|
# to restart kdump service for each event.
|
||
|
|
|
||
|
|
# This script will be called by udev, and make sure kdump service is
|
||
|
|
# restart after all events we are watching are settled.
|
||
|
|
|
||
|
|
# On each call, this script will update try to aquire the $throttle_lock
|
||
|
|
# The first instance acquired the file lock will keep waiting for events
|
||
|
|
# to settle and then reload kdump. Other instances will just exit
|
||
|
|
# In this way, we can make sure kdump service is restarted immediately
|
||
|
|
# and for exactly once after udev events are settled.
|
||
|
|
|
||
|
|
throttle_lock="/var/lock/kdump-udev-throttle"
|
||
|
|
|
||
|
|
exec 9>$throttle_lock
|
||
|
|
if [ $? -ne 0 ]; then
|
||
|
|
echo "Failed to create the lock file! Fallback to non-throttled kdump service restart"
|
||
|
|
/bin/kdumpctl reload
|
||
|
|
exit 1
|
||
|
|
fi
|
||
|
|
|
||
|
|
flock -n 9
|
||
|
|
if [ $? -ne 0 ]; then
|
||
|
|
echo "Throttling kdump restart for concurrent udev event"
|
||
|
|
exit 0
|
||
|
|
fi
|
||
|
|
|
||
|
|
# Wait for at least 1 second, at most 4 seconds for udev to settle
|
||
|
|
# Idealy we will have a less than 1 second lag between udev events settle
|
||
|
|
# and kdump reload
|
||
|
|
sleep 1 && udevadm settle --timeout 3
|
||
|
|
|
||
|
|
# Release the lock, /bin/kdumpctl will block and make the process
|
||
|
|
# holding two locks at the same time and we might miss some events
|
||
|
|
exec 9>&-
|
||
|
|
|
||
|
|
/bin/kdumpctl reload
|
||
|
|
|
||
|
|
exit 0
|