#!/bin/sh
# Copyright (C) 2010 Chris "Pada" Kistner
# Modified by PacoLM to check only shared memory settings
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.

# NOTE: -f you find errors, check that coreutils are installed, if not, run the command below
# apt-get -y install coreutils bc

echo "--- Checking memory setting..."
page_size=$(getconf PAGE_SIZE)
mem_bytes=$(awk '/MemTotal:/ { printf "%0.f",$2 * 1024}' /proc/meminfo)
mb=1048576
mem_bytes_mb=$(expr $mem_bytes / $mb)
shmmax=$(echo "$mem_bytes * 0.90" | bc | cut -f 1 -d '.')
shmmax_mb=$(expr $shmmax / $mb)
shmall=$(expr $mem_bytes / $page_size)
shmmax_cur=$(sysctl -n kernel.shmmax)
shmmax_cur_mb=$(expr $shmmax_cur / $mb)
shmall_cur=$(sysctl -n kernel.shmall)
echo "-- Total memory = $mem_bytes B = $mem_bytes_mb MB"
echo "-- Page size = $page_size B"
echo "-- Current kernel.shmmax = $shmmax_cur B = $shmmax_cur_mb MB"
echo "-- Current kernel.shmall = $shmall_cur pages"
if [ "$shmmax" -eq "$shmmax_cur" ] && [ "$shmall" -eq "$shmall_cur" ]; then
   echo "-- Recommended shm values already set"
else
   echo "-- Recommended: kernel.shmmax = $shmmax B = $shmmax_mb MB"
   echo "-- Recommended: kernel.shmmall = $shmall pages"
fi
# Done
echo "--- Done."

--- Checking memory setting...
-- Total memory = 2121965568 B = 2023 MB
-- Page size = 4096 B
-- Current kernel.shmmax = 33554432 B = 32 MB
-- Current kernel.shmall = 2097152 pages
-- Recommended: kernel.shmmax = 1909769011 B = 1821 MB
-- Recommended: kernel.shmmall = 518058 pages
--- Done.