misc/irqbalance.policy.d/follow-affinity-hint.example

#!/bin/sh
# Do not edit this file, create your own policy script and make it
# executable for irqbalance process, you can use this file as an
# boilerplate.

SYS_DEV_PATH=$1
IRQ_NUM=$2

IRQ_PATH=/proc/irq/$IRQ_NUM
UEVENT_FILE=$SYS_DEV_PATH/uevent

# Scripts below is an example for banning certain IRQs from
# irqbalance and strictly apply their affinity_hint setting
[[ ! -e $UEVENT_FILE ]] && exit 1

# IRQs from following drivers will be handled by this script
# Driver names should be separated by space
AFFINITY_WHITELIST=""

while read line; do
    if [[ $line == "DRIVER="* ]] && \
        [[ " $AFFINITY_WHITELIST " == *" ${line#DRIVER=} "* ]]; then
        affinity_hint=$(cat $IRQ_PATH/affinity_hint 2>/dev/null)
        # Check if affinity_hint value have at least one bit set
        if [[ ! "$affinity_hint" =~ ^[0,]*$ ]]; then
            # Ban it from irqbalance so it won't get balanced,
			# we'll follow its affinity_hint setting
            echo "ban=true"
            # If the affinity_hint value is valid, kernel would set
            # the same value for smp_affinity. But force to set that
            # again in case the IRQ was balanced before.
            echo "$affinity_hint" > $IRQ_PATH/smp_affinity
            # Stop further script processing
            exit 0
        fi
    fi
done <<< "$(cat $UEVENT_FILE)"

exit 1