memory_usage.sh

#!/bin/bash
# Destription: testing memory usage
# Example:	sh memory_usage.sh 500M | sh memory_usage.sh 1G | sh memory_usage.sh release

FILE_NAME=`basename $0`
memsize=$2
function usage(){
	echo "Usage:$FILE_NAME consume memory_size|release ------ the value of memory_size like 100M 2G and etc"
	echo "Example: $FILE_NAME consume 1G"
	echo "	       $FILE_NAME release"	
}
function consume(){
	if [ -d /tmp/memory ]; then
		echo "/tmp/memory already exists"
	else
		mkdir /tmp/memory
	fi
	mount -t tmpfs -o size=$1 tmpfs /tmp/memory
	dd if=/dev/zero of=/tmp/memory/block
}
function release(){
	rm /tmp/memory/block;ret=$?
	if [ $ret != 0 ]; then
		echo "remove memory data failed"
		return $ret
	fi

	umount /tmp/memory;ret=$?
	if [ $ret != 0 ]; then
		echo "umount memory filedir failed"
		return $ret
	fi

	rmdir /tmp/memory;ret=$?
	if [ $ret != 0 ]; then
		echo "remove memory filedir failed"
		return $ret
	fi
}
function main(){
	case "$1" in
		consume) consume $memsize;;
		release) release;;
		      *) usage;exit 1;;
	esac
}
main $*