diff options
| -rw-r--r-- | kernel/sched/fair.c | 89 | ||||
| -rw-r--r-- | kernel/sched/features.h | 18 |
2 files changed, 30 insertions, 77 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 98b2b961df33..43ee84f05d1e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5670,72 +5670,39 @@ static int task_hot(struct task_struct *p, struct lb_env *env) #ifdef CONFIG_NUMA_BALANCING /* - * Returns true if the destination node is the preferred node. - * Needs to match fbq_classify_rq(): if there is a runnable task - * that is not on its preferred node, we should identify it. + * Returns 1, if task migration degrades locality + * Returns 0, if task migration improves locality i.e migration preferred. + * Returns -1, if task migration is not affected by locality. */ -static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env) +static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) { struct numa_group *numa_group = rcu_dereference(p->numa_group); unsigned long src_faults, dst_faults; int src_nid, dst_nid; - if (!sched_feat(NUMA) || !sched_feat(NUMA_FAVOUR_HIGHER) || - !p->numa_faults || !(env->sd->flags & SD_NUMA)) { - return false; - } - - src_nid = cpu_to_node(env->src_cpu); - dst_nid = cpu_to_node(env->dst_cpu); - - if (src_nid == dst_nid) - return false; - - /* Encourage migration to the preferred node. */ - if (dst_nid == p->numa_preferred_nid) - return true; - - /* Migrating away from the preferred node is bad. */ - if (src_nid == p->numa_preferred_nid) - return false; - - if (numa_group) { - src_faults = group_faults(p, src_nid); - dst_faults = group_faults(p, dst_nid); - } else { - src_faults = task_faults(p, src_nid); - dst_faults = task_faults(p, dst_nid); - } - - return dst_faults > src_faults; -} - - -static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env) -{ - struct numa_group *numa_group = rcu_dereference(p->numa_group); - unsigned long src_faults, dst_faults; - int src_nid, dst_nid; - - if (!sched_feat(NUMA) || !sched_feat(NUMA_RESIST_LOWER)) - return false; - if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) - return false; + return -1; + + if (!sched_feat(NUMA)) + return -1; src_nid = cpu_to_node(env->src_cpu); dst_nid = cpu_to_node(env->dst_cpu); if (src_nid == dst_nid) - return false; + return -1; - /* Migrating away from the preferred node is bad. */ - if (src_nid == p->numa_preferred_nid) - return true; + /* Migrating away from the preferred node is always bad. */ + if (src_nid == p->numa_preferred_nid) { + if (env->src_rq->nr_running > env->src_rq->nr_preferred_running) + return 1; + else + return -1; + } /* Encourage migration to the preferred node. */ if (dst_nid == p->numa_preferred_nid) - return false; + return 0; if (numa_group) { src_faults = group_faults(p, src_nid); @@ -5749,16 +5716,10 @@ static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env) } #else -static inline bool migrate_improves_locality(struct task_struct *p, +static inline int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) { - return false; -} - -static inline bool migrate_degrades_locality(struct task_struct *p, - struct lb_env *env) -{ - return false; + return -1; } #endif @@ -5768,7 +5729,7 @@ static inline bool migrate_degrades_locality(struct task_struct *p, static int can_migrate_task(struct task_struct *p, struct lb_env *env) { - int tsk_cache_hot = 0; + int tsk_cache_hot; lockdep_assert_held(&env->src_rq->lock); @@ -5826,13 +5787,13 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) * 2) task is cache cold, or * 3) too many balance attempts have failed. */ - tsk_cache_hot = task_hot(p, env); - if (!tsk_cache_hot) - tsk_cache_hot = migrate_degrades_locality(p, env); + tsk_cache_hot = migrate_degrades_locality(p, env); + if (tsk_cache_hot == -1) + tsk_cache_hot = task_hot(p, env); - if (migrate_improves_locality(p, env) || !tsk_cache_hot || + if (tsk_cache_hot <= 0 || env->sd->nr_balance_failed > env->sd->cache_nice_tries) { - if (tsk_cache_hot) { + if (tsk_cache_hot == 1) { schedstat_inc(env->sd, lb_hot_gained[env->idle]); schedstat_inc(p, se.statistics.nr_forced_migrations); } diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 91e33cd485f6..83a50e7ca533 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -79,20 +79,12 @@ SCHED_FEAT(LB_MIN, false) * numa_balancing= */ #ifdef CONFIG_NUMA_BALANCING -SCHED_FEAT(NUMA, false) /* - * NUMA_FAVOUR_HIGHER will favor moving tasks towards nodes where a - * higher number of hinting faults are recorded during active load - * balancing. + * NUMA will favor moving tasks towards nodes where a higher number of + * hinting faults are recorded during active load balancing. It will + * resist moving tasks towards nodes where a lower number of hinting + * faults have been recorded. */ -SCHED_FEAT(NUMA_FAVOUR_HIGHER, true) - -/* - * NUMA_RESIST_LOWER will resist moving tasks towards nodes where a - * lower number of hinting faults have been recorded. As this has - * the potential to prevent a task ever migrating to a new node - * due to CPU overload it is disabled by default. - */ -SCHED_FEAT(NUMA_RESIST_LOWER, false) +SCHED_FEAT(NUMA, true) #endif |