From: Rik van Riel <riel@xxxxxxxxxx> The faults_from statistics are used to maintain an active_nodes nodemask per numa_group. This allows us to be smarter about when to do numa migrations. Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> --- kernel/sched/fair.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 89b5217..91b8f11 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -869,6 +869,7 @@ struct numa_group { struct list_head task_list; struct rcu_head rcu; + nodemask_t active_nodes; unsigned long total_faults; unsigned long *faults_from; unsigned long faults[0]; @@ -1228,6 +1229,34 @@ static void numa_migrate_preferred(struct task_struct *p) task_numa_migrate(p); } +static void update_numa_active_node_mask(struct task_struct *p) +{ + unsigned long faults, max_faults = 0; + struct numa_group *numa_group = p->numa_group; + int nid; + + for_each_online_node(nid) { + faults = numa_group->faults_from[task_faults_idx(nid, 0)] + + numa_group->faults_from[task_faults_idx(nid, 1)]; + if (faults > max_faults) + max_faults = faults; + } + + /* + * Mark any node where more than 40% of the faults + * (half minus some hysteresis) as part of this + * group's active nodes. + */ + for_each_online_node(nid) { + faults = numa_group->faults_from[task_faults_idx(nid, 0)] + + numa_group->faults_from[task_faults_idx(nid, 1)]; + if (faults > max_faults * 4 / 10) + node_set(nid, numa_group->active_nodes); + else + node_clear(nid, numa_group->active_nodes); + } +} + /* * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS * increments. The more local the fault statistics are, the higher the scan @@ -1387,6 +1416,8 @@ static void task_numa_placement(struct task_struct *p) } } + update_numa_active_node_mask(p); + spin_unlock(group_lock); } @@ -1433,6 +1464,8 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags, /* Second half of the array tracks where faults come from */ grp->faults_from = grp->faults + 2 * nr_node_ids; + node_set(task_node(current), grp->active_nodes); + for (i = 0; i < 4*nr_node_ids; i++) grp->faults[i] = p->numa_faults[i]; -- 1.8.3.1 -- 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>