[PATCH] sched: make idlest_group/cpu cpus_allowed-aware

Add relevant checks into find_idlest_group() and find_idlest_cpu() to make
them return only the groups that have allowed CPUs and allowed CPUs
respectively.

Signed-off-by: M.Baris Demiray <baris@labristeknoloji.com>
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index ef748e691608..bac23fb418f6 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -966,8 +966,11 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
                 int local_group;
                 int i;
 
+                /* Skip over this group if it has no CPUs allowed */
+                if (!cpus_intersects(group->cpumask, p->cpus_allowed))
+                        goto nextgroup;
+
                 local_group = cpu_isset(this_cpu, group->cpumask);
-                /* XXX: put a cpus allowed check */
 
                 /* Tally up the load of all CPUs in the group */
                 avg_load = 0;
@@ -992,6 +995,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
                         min_load = avg_load;
                         idlest = group;
                 }
+nextgroup:
                 group = group->next;
         } while (group != sd->groups);
 
@@ -1003,13 +1007,18 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
 /*
  * find_idlest_queue - find the idlest runqueue among the cpus in group.
  */
-static int find_idlest_cpu(struct sched_group *group, int this_cpu)
+static int find_idlest_cpu(struct sched_group *group,
+                        struct task_struct *p, int this_cpu)
 {
+        cpumask_t tmp;
         unsigned long load, min_load = ULONG_MAX;
         int idlest = -1;
         int i;
 
-        for_each_cpu_mask(i, group->cpumask) {
+        /* Traverse only the allowed CPUs */
+        cpus_and(tmp, group->cpumask, p->cpus_allowed);
+
+        for_each_cpu_mask(i, tmp) {
                 load = source_load(i, 0);
 
                 if (load < min_load || (load == min_load && i == this_cpu)) {
@@ -1052,7 +1061,7 @@ static int sched_balance_self(int cpu, int flag)
                 if (!group)
                         goto nextlevel;
 
-                new_cpu = find_idlest_cpu(group, cpu);
+                new_cpu = find_idlest_cpu(group, t, cpu);
                 if (new_cpu == -1 || new_cpu == cpu)
                         goto nextlevel;