#!/bin/bash

# SPDX-FileCopyrightText: Copyright (c) 2019-2020 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: BSD-3-Clause
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
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# 3. Neither the name of the copyright holder nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


# Minimum available memory limit (in MB)
threshold=150

# Check time interval (in sec)
interval=300

mem_warning()
{
	while : ; do
		available="$(free -m | awk '/Mem:/{print $7}')"

		if [ "${available}" -lt "${threshold}" ]; then
			free_mem="$(free -m|awk '/^Mem:/{print $4}')"
			buffers="$(free -m|awk '/^Mem:/{print $6}')"
			message="Memory available for new process: ${available} MB\n"
			message="${message} free ${free_mem} MB, buffers/cache ${buffers} MB"
			xusers=($(who|grep -E "\(:[0-9](\.[0-9])*\)"|awk '{print $1$5}'|sort -u))
			for xuser in "${xusers}"; do
			    name=(${xuser/(/ })
			    display=${name[1]/)/}
			    dbus_address=unix:path=/run/user/$(id -u ${name[0]})/bus
			    sudo -u "${name[0]}" display="${display}" \
				    DBUS_SESSION_BUS_ADDRESS="${dbus_address}" PATH="${PATH}" \
				    notify-send "Low Memory Warning" "${message}"
			done
		fi
		sleep "${interval}"
	done
}

# Read Total memory size
total_mem=$(free -g|awk '/^Mem:/{print $2}')

# If RAM size is less than 8 GB, mem_warning will be invoked
if [ "${total_mem}" -lt 8 ]; then
	mem_warning
fi