Merge pull request #3 from Stefsinn/master

Adding scripts for auto-allocation of HugePages

fstab.txt

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+
+#
+# /etc/fstab: static file system information
+#
+# HugePages
+hugetlbfs       /dev/hugepages/2M     hugetlbfs     mode=1770,gid=994,pagesize=2M   0 0
+hugetlbfs       /dev/hugepages/1G     hugetlbfs     mode=1770,gid=994,pagesize=1G   0 0

libvirt_hooks/hooks/alloc_hugepages.sh

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+#! /bin/bash
+#
+# Author: 
+#
+# This hook automatically (un-)allocates static HugePages when starting/stopping a VM.
+# This file depends on the Passthrough POST hook helper script found in this repo.
+# Place this script in BOTH these directories (or symlink it): 
+# $SYSCONFDIR/libvirt/hooks/qemu.d/your_vm/prepare/begin/
+# $SYSCONFDIR/libvirt/hooks/qemu.d/your_vm/release/end/
+# $SYSCONFDIR usually is /etc/libvirt.
+# Set the files as executable through `chmod +x`.
+#
+# Also make sure to configure your VM's XML file and /etc/fstab or this script won't work.
+
+# Get size of VM-Memory and HugePages
+XML_PATH=/etc/libvirt/qemu/$1.xml
+MEM_HOST=$(grep 'MemAvailable' /proc/meminfo | grep -ohE '[[:digit:]]+')    # Available host memory
+MEM_GUEST=$(grep '<memory unit' $XML_PATH    | grep -ohE '[[:digit:]]+')    # VM memory to be allocated
+HPG_SIZE=$(grep '<page size' $XML_PATH       | grep -ohE '[[:digit:]]+')    # HugePage size
+
+function allocPages {
+    # Define path and current amount of HugePages
+    HPG_PATH=/sys/devices/system/node/node0/hugepages/hugepages-"$HPG_SIZE"kB/nr_hugepages
+    HPG_CURRENT=$(cat $HPG_PATH)
+
+    # Allocate HugePages
+    ((HPG_NEW = HPG_CURRENT + MEM_GUEST / HPG_SIZE ))
+    echo $HPG_NEW > $HPG_PATH
+}
+
+function prepMemory {
+    # Prepare memory for allocation
+    echo 1 > /proc/sys/vm/compact_memory
+    #echo 3 > /proc/sys/vm/drop_caches
+    #echo 1 > /proc/sys/vm/overcommit_memory
+}
+
+# If VM fits into memory, then allocate HugePages
+if (($MEM_GUEST < $MEM_HOST)); then
+    allocPages
+fi

libvirt_hooks/hooks/unalloc_hugepages.sh

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+#! /bin/bash
+#
+# Author: 
+#
+# This hook automatically (un-)allocates static HugePages when starting/stopping a VM.
+# This file depends on the Passthrough POST hook helper script found in this repo.
+# Place this script in BOTH these directories (or symlink it): 
+# $SYSCONFDIR/libvirt/hooks/qemu.d/your_vm/prepare/begin/
+# $SYSCONFDIR/libvirt/hooks/qemu.d/your_vm/release/end/
+# $SYSCONFDIR usually is /etc/libvirt.
+# Set the files as executable through `chmod +x`.
+#
+# Also make sure to configure your VM's XML file and /etc/fstab or this script won't work.
+
+# Get size of VM-Memory and HugePages
+XML_PATH=/etc/libvirt/qemu/$1.xml
+MEM_GUEST=$(grep '<memory unit' $XML_PATH    | grep -ohE '[[:digit:]]+')    # VM memory to be allocated
+HPG_SIZE=$(grep '<page size' $XML_PATH       | grep -ohE '[[:digit:]]+')    # HugePage size
+
+function unallocPages {
+    # Define path and current amount of HugePages
+    HPG_PATH=/sys/devices/system/node/node0/hugepages/hugepages-"$HPG_SIZE"kB/nr_hugepages
+    HPG_CURRENT=$(cat $HPG_PATH)
+
+    # Unallocate HugePages
+    ((HPG_NEW = HPG_CURRENT - MEM_GUEST / HPG_SIZE ))
+    echo $HPG_NEW > $HPG_PATH
+}
+
+# Call function to unallocate HugePages
+unallocPages