diff options
| -rw-r--r-- | kernel/sched/fair.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8c1ac01a10d5..fcc968669aea 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1707,7 +1707,7 @@ static bool load_too_imbalanced(long src_load, long dst_load, * into account that it might be best if task running on the dst_cpu should * be exchanged with the source task */ -static void task_numa_compare(struct task_numa_env *env, +static bool task_numa_compare(struct task_numa_env *env, long taskimp, long groupimp, bool maymove) { struct numa_group *cur_ng, *p_ng = deref_curr_numa_group(env->p); @@ -1718,9 +1718,10 @@ static void task_numa_compare(struct task_numa_env *env, int dist = env->dist; long moveimp = imp; long load; + bool stopsearch = false; if (READ_ONCE(dst_rq->numa_migrate_on)) - return; + return false; rcu_read_lock(); cur = rcu_dereference(dst_rq->curr); @@ -1731,8 +1732,10 @@ static void task_numa_compare(struct task_numa_env *env, * Because we have preemption enabled we can get migrated around and * end try selecting ourselves (current == env->p) as a swap candidate. */ - if (cur == env->p) + if (cur == env->p) { + stopsearch = true; goto unlock; + } if (!cur) { if (maymove && moveimp >= env->best_imp) @@ -1860,8 +1863,27 @@ assign: } task_numa_assign(env, cur, imp); + + /* + * If a move to idle is allowed because there is capacity or load + * balance improves then stop the search. While a better swap + * candidate may exist, a search is not free. + */ + if (maymove && !cur && env->best_cpu >= 0 && idle_cpu(env->best_cpu)) + stopsearch = true; + + /* + * If a swap candidate must be identified and the current best task + * moves its preferred node then stop the search. + */ + if (!maymove && env->best_task && + env->best_task->numa_preferred_nid == env->src_nid) { + stopsearch = true; + } unlock: rcu_read_unlock(); + + return stopsearch; } static void task_numa_find_cpu(struct task_numa_env *env, @@ -1916,7 +1938,8 @@ static void task_numa_find_cpu(struct task_numa_env *env, continue; env->dst_cpu = cpu; - task_numa_compare(env, taskimp, groupimp, maymove); + if (task_numa_compare(env, taskimp, groupimp, maymove)) + break; } } |