[PATCH 3/4] sched,numa: store numa_group's preferred nid

[riel@redhat.com]

From: Rik van Riel <riel@redhat.com>

Store a numa_group's preferred nid. Used by the next patch to pull
workloads towards their preferred nodes.

Signed-off-by: Rik van Riel <riel@redhat.com>
Tested-by: Chegu Vinod <chegu_vinod@hp.com>
---
 kernel/sched/fair.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5925667..99cc829 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -864,6 +864,7 @@ struct numa_group {
 
 	spinlock_t lock; /* nr_tasks, tasks */
 	int nr_tasks;
+	int preferred_nid;
 	pid_t gid;
 	struct list_head task_list;
 
@@ -1642,6 +1643,7 @@ static void task_numa_placement(struct task_struct *p)
 
 	if (p->numa_group) {
 		update_numa_active_node_mask(p->numa_group);
+		p->numa_group->preferred_nid = max_group_nid;
 		/*
 		 * If the preferred task and group nids are different,
 		 * iterate over the nodes again to find the best place.
@@ -1701,6 +1703,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
 		spin_lock_init(&grp->lock);
 		INIT_LIST_HEAD(&grp->task_list);
 		grp->gid = p->pid;
+		grp->preferred_nid = -1;
 		/* Second half of the array tracks nids where faults happen */
 		grp->faults_cpu = grp->faults + NR_NUMA_HINT_FAULT_TYPES *
 						nr_node_ids;
-- 
1.8.5.3