解决ubuntu18下桌面经常卡死的问题

1 准备一个定时释放内存的命令：freemem.sh

# vim freemem.sh
  
#!/bin/bash
used=`free -m | awk 'NR==2' | awk '{print $3}'`
free=`free -m | awk 'NR==2' | awk '{print $4}'`
 
filename=/var/log/mem.log
filesize=`ls -l $filename | awk '{ print $5 }'`
maxsize=$((1024*2))
if [ $filesize -gt $maxsize ]
then
    sudo rm $filename
else
    echo ""
fi
 
 
echo "===========================" >> /var/log/mem.log
date >> /var/log/mem.log
echo "Memory usage | [Use：${used}MB][Free：${free}MB]" >> /var/log/mem.log
  
if [ $free -le 100 ] ; then
                sync && echo 1 > /proc/sys/vm/drop_cach
                sync && echo 2 > /proc/sys/vm/drop_caches
                sync && echo 3 > /proc/sys/vm/drop_caches
                echo "OK" >> /var/log/mem.log
else
                echo "Not required" >> /var/log/mem.log
fi

2 将执行任务写入定时任务

sudo crontab -e
 
结尾添加：
*/1 * * * *  sudo sh /home/dxs/software/freemem.sh
## 意思是：设置每1min执行一次，会自动写入之前脚本里指定的log 

3 重新启动定时任务

重启服务：
sudo service cron restart
 
=============================
修改rsyslog
 
sudo vim /etc/rsyslog.d/50-default.conf
 
cron.*              /var/log/cron.log    #将cron前面的注释符去掉 
 
重启rsyslog
 
sudo  service rsyslog  restart
sudo service cron restart
 
查看crontab日志
 
 tail -f /var/log/cron.log