#!/bin/sh

. ./hw_vars

if [ "$SwapTotal" -eq 0 ]; then
        echo "No swap space. Please setup swap before running $0" >&2
        exit 1
fi

[ -n "$unit_size" ] || unit_size=$((MemAvailable << 10))

TMP=/tmp

# start N detached processes and do write first to consume all memory
# then wait for SIGUSR1 to resume to do read
./usemem -n $nr_task -W -d -p $TMP/pidfile $((unit_size / nr_task))

# Now that the N detached processes are done, start another process
# to consume memory to push pages allocated by the first N processes
# to swap.
# Also, redirect its output to /dev/null so that it won't output any
# statistics related information
swapfree=$(grep SwapFree /proc/meminfo |awk '{print $2}')
swapfree=$((swapfree << 10))
pushsize=$(($swapfree < $unit_size ? $swapfree : $unit_size))
./usemem $pushsize >/dev/null
# do it again to push more memory to swap
./usemem $pushsize >/dev/null

# wake those detached processes up to do read
kill -USR1 `cat $TMP/pidfile`

any_pid_alive()
{
	local pidfile=$1
	for pid in $(cat $pidfile)
	do
		test -d /proc/$pid && return
	done
	return 1
}

# wait till those detached processes exit
while true
do
	sleep 5
	any_pid_alive $TMP/pidfile && continue
	break
done

rm $TMP/pidfile