diff options
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 377c77b35751..2e8aadeac3a7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8762,6 +8762,16 @@ static bool update_pick_idlest(struct sched_group *idlest, } /* + * Allow a NUMA imbalance if busy CPUs is less than 25% of the domain. + * This is an approximation as the number of running tasks may not be + * related to the number of busy CPUs due to sched_setaffinity. + */ +static inline bool allow_numa_imbalance(int dst_running, int dst_weight) +{ + return (dst_running < (dst_weight >> 2)); +} + +/* * find_idlest_group() finds and returns the least busy CPU group within the * domain. * @@ -8893,7 +8903,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) * a real need of migration, periodic load balance will * take care of it. */ - if (local_sgs.idle_cpus) + if (allow_numa_imbalance(local_sgs.sum_nr_running, sd->span_weight)) return NULL; } @@ -9000,11 +9010,14 @@ next_group: static inline long adjust_numa_imbalance(int imbalance, int dst_running, int dst_weight) { + if (!allow_numa_imbalance(dst_running, dst_weight)) + return imbalance; + /* * Allow a small imbalance based on a simple pair of communicating * tasks that remain local when the destination is lightly loaded. */ - if (dst_running < (dst_weight >> 2) && imbalance <= NUMA_IMBALANCE_MIN) + if (imbalance <= NUMA_IMBALANCE_MIN) return 0; return imbalance; |