#!/bin/bash

LIMIT=

LOG_FILE="/data/logs/timing_dropcaches.log"

#定时清理系统内存

#https://blog.csdn.net/gaojinshan/article/details/40710369

used=`free -m | awk 'NR==2' | awk '{print $3}'`

free=`free -m | awk 'NR==2' | awk '{print $4}'`

echo "===========================" >> $LOG_FILE

date +"%Y-%m-%d %H:%M.%S" >> $LOG_FILE

echo "Memory usage | [Use：${used}MB][Free：${free}MB] | limit[${LIMIT}MB]" >> $LOG_FILE

# drop caches when the free memory less than 512M

if [ $free -le $LIMIT ] ; then

 #sync && echo  > /proc/sys/vm/drop_caches

 #sync && echo  > /proc/sys/vm/drop_caches

 sync && echo  > /proc/sys/vm/drop_caches

 echo "OK" >> $LOG_FILE

else

 echo "Not required" >> $LOG_FILE

fi

#每半小时检查内存使用情况，并清理一次内存
*/30 * * * *  /data/shell/timing_dropcaches.sh >> /data/logs/timing_dropcaches.log

#删除3天前的日志
0 1 * * * /usr/bin/find /data/logs/ -name *.log -mtime +3 | grep 2018 | xargs rm -Rf {} > /dev/null 2>&1