From: Rik van Riel <riel@xxxxxxxxxx> This patch separately considers task and group affinities when searching for swap candidates during task NUMA placement. If tasks are not part of a group or the same group then the task weights are considered. Otherwise the group weights are compared. Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> --- kernel/sched/fair.c | 59 ++++++++++++++++++++++++++++++++--------------------- 1 file changed, 36 insertions(+), 23 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 58d1070..e7da6f2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1039,13 +1039,15 @@ static void task_numa_assign(struct task_numa_env *env, * 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, long imp) +static void task_numa_compare(struct task_numa_env *env, + long taskimp, long groupimp) { struct rq *src_rq = cpu_rq(env->src_cpu); struct rq *dst_rq = cpu_rq(env->dst_cpu); struct task_struct *cur; long dst_load, src_load; long load; + long imp = (groupimp > 0) ? groupimp : taskimp; rcu_read_lock(); cur = ACCESS_ONCE(dst_rq->curr); @@ -1064,10 +1066,19 @@ static void task_numa_compare(struct task_numa_env *env, long imp) if (!cpumask_test_cpu(env->src_cpu, tsk_cpus_allowed(cur))) goto unlock; - imp += task_weight(cur, env->src_nid) + - group_weight(cur, env->src_nid) - - task_weight(cur, env->dst_nid) - - group_weight(cur, env->dst_nid); + /* + * If dst and source tasks are in the same NUMA group, or not + * in any group then look only at task weights otherwise give + * priority to the group weights. + */ + if (!cur->numa_group || !env->p->numa_group || + cur->numa_group == env->p->numa_group) { + imp = taskimp + task_weight(cur, env->src_nid) - + task_weight(cur, env->dst_nid); + } else { + imp = groupimp + group_weight(cur, env->src_nid) - + group_weight(cur, env->dst_nid); + } } if (imp < env->best_imp) @@ -1117,7 +1128,8 @@ unlock: rcu_read_unlock(); } -static void task_numa_find_cpu(struct task_numa_env *env, long imp) +static void task_numa_find_cpu(struct task_numa_env *env, + long taskimp, long groupimp) { int cpu; @@ -1127,7 +1139,7 @@ static void task_numa_find_cpu(struct task_numa_env *env, long imp) continue; env->dst_cpu = cpu; - task_numa_compare(env, imp); + task_numa_compare(env, taskimp, groupimp); } } @@ -1146,9 +1158,9 @@ static int task_numa_migrate(struct task_struct *p) .best_cpu = -1 }; struct sched_domain *sd; - unsigned long weight; + unsigned long taskweight, groupweight; int nid, ret; - long imp; + long taskimp, groupimp; /* * Pick the lowest SD_NUMA domain, as that would have the smallest @@ -1163,15 +1175,17 @@ static int task_numa_migrate(struct task_struct *p) env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2; rcu_read_unlock(); - weight = task_weight(p, env.src_nid) + group_weight(p, env.src_nid); + taskweight = task_weight(p, env.src_nid); + groupweight = group_weight(p, env.src_nid); update_numa_stats(&env.src_stats, env.src_nid); env.dst_nid = p->numa_preferred_nid; - imp = task_weight(p, env.dst_nid) + group_weight(p, env.dst_nid) - weight; + taskimp = task_weight(p, env.dst_nid) - taskweight; + groupimp = group_weight(p, env.dst_nid) - groupweight; update_numa_stats(&env.dst_stats, env.dst_nid); /* If the preferred nid has capacity, try to use it. */ if (env.dst_stats.has_capacity) - task_numa_find_cpu(&env, imp); + task_numa_find_cpu(&env, taskimp, groupimp); /* No space available on the preferred nid. Look elsewhere. */ if (env.best_cpu == -1) { @@ -1180,13 +1194,14 @@ static int task_numa_migrate(struct task_struct *p) continue; /* Only consider nodes where both task and groups benefit */ - imp = task_weight(p, nid) + group_weight(p, nid) - weight; - if (imp < 0) + taskimp = task_weight(p, nid) - taskweight; + groupimp = group_weight(p, nid) - groupweight; + if (taskimp < 0 && groupimp < 0) continue; env.dst_nid = nid; update_numa_stats(&env.dst_stats, env.dst_nid); - task_numa_find_cpu(&env, imp); + task_numa_find_cpu(&env, taskimp, groupimp); } } @@ -4678,10 +4693,9 @@ static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env) if (dst_nid == p->numa_preferred_nid) return true; - /* After the task has settled, check if the new node is better. */ - if (p->numa_migrate_seq >= sysctl_numa_balancing_settle_count && - task_weight(p, dst_nid) + group_weight(p, dst_nid) > - task_weight(p, src_nid) + group_weight(p, src_nid)) + /* If both task and group weight improve, this move is a winner. */ + if (task_weight(p, dst_nid) > task_weight(p, src_nid) && + group_weight(p, dst_nid) > group_weight(p, src_nid)) return true; return false; @@ -4708,10 +4722,9 @@ static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env) if (src_nid == p->numa_preferred_nid) return true; - /* After the task has settled, check if the new node is worse. */ - if (p->numa_migrate_seq >= sysctl_numa_balancing_settle_count && - task_weight(p, dst_nid) + group_weight(p, dst_nid) < - task_weight(p, src_nid) + group_weight(p, src_nid)) + /* If either task or group weight get worse, don't do it. */ + if (task_weight(p, dst_nid) < task_weight(p, src_nid) || + group_weight(p, dst_nid) < group_weight(p, src_nid)) return true; return false; -- 1.8.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>