Hot answers tagged memory
"hung tasks" are bugs that cause the kernel to leave a task stuck in uninterruptible "D" state. A task/process in that state cannot be killed, neither with kill -9. Your message in /var/log/messages means that the task 4123, obviously the mysql daemon is in that state since 120 seconds. That means the mysql daemon waits for ressources. Mostly the "D" state ...
you can pipe the output of ps and sort the column of memory depending on the requirement. ps aux | sort -r -k4
echo 0 > /proc/sys/kernel/hung_task_timeout_secs only silences the warning. Besides that it has no effect whatsoever. Any value above zero will cause this message to be issued whenever a task is blocked for that amount of time. The warning is given to indicate a problem with the system. In my experience it means that the process is blocked in kernel ...
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