#!/bin/bash

MEMORY=24576
## Calculate number of hugepages to allocate from memory (in MB)
HUGEPAGES="$(($MEMORY/$(($(grep Hugepagesize /proc/meminfo | awk '{print $2}')/1024))))"
## Node to allocate on (node1 for this VM)
NODESPATH=/sys/devices/system/node/node1

echo "Allocating hugepages..."
echo $HUGEPAGES > $NODESPATH/hugepages/hugepages-2048kB/nr_hugepages
ALLOC_PAGES=$(cat $NODESPATH/hugepages/hugepages-2048kB/nr_hugepages)

TRIES=0
while (( $ALLOC_PAGES != $HUGEPAGES && $TRIES < 1000 ))
do
    echo 1 > /proc/sys/vm/compact_memory            ## defrag ram
    echo $HUGEPAGES > $NODESPATH/hugepages/hugepages-2048kB/nr_hugepages
    ALLOC_PAGES=$(cat $NODESPATH/hugepages/hugepages-2048kB/nr_hugepages)
    echo "Succesfully allocated $ALLOC_PAGES / $HUGEPAGES"
    let TRIES+=1
done

if [ "$ALLOC_PAGES" -ne "$HUGEPAGES" ]
then
    echo "Not able to allocate all hugepages. Reverting..."
    echo 0 > $NODESPATH/hugepages/hugepages-2048kB/nr_hugepages
    exit 1
fi