Merge alloc_hugepages, and unalloc_hugepages into one script, add checks and logging

libvirt_hooks/hooks/alloc_hugepages.sh

@@ -1,39 +0,0 @@
-#! /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 > $HPG_PATH
-}
-
-function prepMemory {
-    # Prepare memory for allocation
-    echo 1 > /proc/sys/vm/compact_memory
-}
-
-# If VM fits into memory, then allocate HugePages
-if (($MEM_GUEST < $MEM_HOST)); then
-    allocPages
-fi

libvirt_hooks/hooks/hugepages.sh

@@ -0,0 +1,67 @@
+#! /bin/bash
+#
+# Author: Stefsinn (https://github.com/Stefsinn)
+#
+# This hook automatically un-allocates static HugePages when stopping a VM.
+# This file depends on the PassthroughPOST hook helper script found here:
+# https://github.com/PassthroughPOST/VFIO-Tools/tree/master/libvirt_hooks
+# 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.
+# Get inputs from libvirt
+GUEST_NAME="$1"
+GUEST_ACTION="$2/$3"
+# Get path to guest XML
+XML_PATH="/etc/libvirt/qemu/$GUEST_NAME.xml"
+# Get guest HugePage size
+HPG_SIZE=$(grep '<page size' "$XML_PATH" | grep -ohE '[[:digit:]]+')
+# Set path to HugePages
+HPG_PATH="/sys/devices/system/node/node0/hugepages"
+# Get current number of HugePages
+HPG_CURRENT=$(cat "${HPG_PATH}/hugepages-${HPG_SIZE}kB/nr_hugepages")
+# Get amount of memory used by the guest
+GUEST_MEM=$(grep '<memory unit' "$XML_PATH" | grep -ohE '[[:digit:]]+')
+
+# We define functions here named for each step libvirt calls the hook against
+#   respectively. These will be ran after checks pass at the end of the script.
+function prepare/begin {
+  # Allocate HugePages
+  ((HPG_NEW = HPG_CURRENT + GUEST_MEM / HPG_SIZE ))
+  echo "$HPG_NEW" > "$HPG_PATH"
+  kmessageNotify "Allocating ${GUEST_MEM}kB of HugePages for VM ${GUEST_NAME}"
+}
+
+function release/end {
+	# Unallocate HugePages
+	((HPG_NEW = HPG_CURRENT - GUEST_MEM / HPG_SIZE ))
+	echo "$HPG_NEW" > "$HPG_PATH"
+  kmessageNotify "Releasing ${GUEST_MEM}kB of HugePages for VM ${GUEST_NAME}"
+}
+
+function kmessageNotify {
+  MESSAGE="$1"
+  while read -r line; do
+    echo "libvirt_qemu hugepages: ${line}" > /dev/kmsg 2>&1
+  done < <(echo "${MESSAGE}")
+}
+
+# Do some checks before continuing
+if [[ $HPG_SIZE -eq 0 ]]; then
+  # Break if HugePage size is 0
+  echo "ERROR: HugePage size cannot be 0." >&2
+  exit 1
+elif [[ -z $GUEST_MEM ]]; then
+  echo "ERROR: Can't determine guest's memory allocation" >&2
+  exit 1
+elif [[ ! -d "$HPG_PATH"  ]]; then
+  # Break if HugePages path doesn't exist
+  echo "ERROR: ${HPG_PATH} does not exist. (HugePages disabled in kernel?)" >&2
+  exit 1
+elif [[ -z $HPG_SIZE ]]; then
+  # This exits silently if HugePages appear disabled for a guest
+  exit 0
+fi
+
+# All checks passed, continue
+${GUEST_ACTION}

libvirt_hooks/hooks/unalloc_hugepages.sh

@@ -1,33 +0,0 @@
-#! /bin/bash
-#
-# Author: Stefsinn (https://github.com/Stefsinn)
-#
-# This hook automatically un-allocates static HugePages when stopping a VM.
-# This file depends on the PassthroughPOST hook helper script found here:
-# https://github.com/PassthroughPOST/VFIO-Tools/tree/master/libvirt_hooks
-# 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/
-# $SYSCONFDIR usually is /etc/libvirt.
-# Get path to guest XML
-XML_PATH="/etc/libvirt/qemu/${1}.xml"
-# Get guest HugePage size
-HPG_SIZE=$(grep '<page size' "$XML_PATH" | grep -ohE '[[:digit:]]+')
-# Set path to HugePages
-HPG_PATH="/sys/devices/system/node/node0/hugepages"
-
-function unallocPages {
-	# VM memory to be allocated
-	MEM_GUEST=$(grep '<memory unit' "$XML_PATH" | grep -ohE '[[:digit:]]+')
-	# Current number of HugePages
-	HPG_CURRENT=$(cat "${HPG_PATH}/hugepages-${HPG_SIZE}kB/nr_hugepages")
-
-	# Unallocate HugePages
-	((HPG_NEW = HPG_CURRENT - MEM_GUEST / HPG_SIZE ))
-	echo "$HPG_NEW" > "$HPG_PATH"
-}
-
-# Call function to unallocate HugePages if HugePage count is greater than 0
-if [[ HPG_SIZE -gt 0 ]]; then
-	unallocPages
-fi