diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index b66602ad7b33..b7ca5bf9acfc 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -80,6 +80,10 @@ config HOTPLUG_CPU can be controlled through /sys/devices/system/cpu/cpu#. Say N if you want to disable CPU hotplug. +config DEFAULT_MIGRATION_COST + int + default "1000000" + config MATHEMU bool "IEEE FPU emulation" depends on MARCH_G5 diff --git a/kernel/sched.c b/kernel/sched.c index 66d957227de9..12d291bf3379 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5058,7 +5058,18 @@ static void init_sched_build_groups(struct sched_group groups[], cpumask_t span, #define MAX_DOMAIN_DISTANCE 32 static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] = - { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = -1LL }; + { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = +/* + * Architectures may override the migration cost and thus avoid + * boot-time calibration. Unit is nanoseconds. Mostly useful for + * virtualized hardware: + */ +#ifdef CONFIG_DEFAULT_MIGRATION_COST + CONFIG_DEFAULT_MIGRATION_COST +#else + -1LL +#endif +}; /* * Allow override of migration cost - in units of microseconds.