sched: dynamically update the root-domain span/online maps

The baseline code statically builds the span maps when the domain is formed.
Previous attempts at dynamically updating the maps caused a suspend-to-ram
regression, which should now be fixed.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
CC: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 19 insertions, 12 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 5834c7fb79a5..02d468844a91 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -359,8 +359,6 @@ struct rt_rq {
  * exclusive cpuset is created, we also create and attach a new root-domain
  * object.
  *
- * By default the system creates a single root-domain with all cpus as
- * members (mimicking the global state we have today).
  */
 struct root_domain {
         atomic_t refcount;
@@ -375,6 +373,10 @@ struct root_domain {
         atomic_t rto_count;
 };
 
+/*
+ * By default the system creates a single root-domain with all cpus as
+ * members (mimicking the global state we have today).
+ */
 static struct root_domain def_root_domain;
 
 #endif
@@ -5859,6 +5861,9 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd)
                                 class->leave_domain(rq);
                 }
 
+                cpu_clear(rq->cpu, old_rd->span);
+                cpu_clear(rq->cpu, old_rd->online);
+
                 if (atomic_dec_and_test(&old_rd->refcount))
                         kfree(old_rd);
         }
@@ -5866,6 +5871,10 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd)
         atomic_inc(&rd->refcount);
         rq->rd = rd;
 
+        cpu_set(rq->cpu, rd->span);
+        if (cpu_isset(rq->cpu, cpu_online_map))
+                cpu_set(rq->cpu, rd->online);
+
         for (class = sched_class_highest; class; class = class->next) {
                 if (class->join_domain)
                         class->join_domain(rq);
@@ -5874,23 +5883,21 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd)
         spin_unlock_irqrestore(&rq->lock, flags);
 }
 
-static void init_rootdomain(struct root_domain *rd, const cpumask_t *map)
+static void init_rootdomain(struct root_domain *rd)
 {
         memset(rd, 0, sizeof(*rd));
 
-        rd->span = *map;
-        cpus_and(rd->online, rd->span, cpu_online_map);
+        cpus_clear(rd->span);
+        cpus_clear(rd->online);
 }
 
 static void init_defrootdomain(void)
 {
-        cpumask_t cpus = CPU_MASK_ALL;
-
-        init_rootdomain(&def_root_domain, &cpus);
+        init_rootdomain(&def_root_domain);
         atomic_set(&def_root_domain.refcount, 1);
 }
 
-static struct root_domain *alloc_rootdomain(const cpumask_t *map)
+static struct root_domain *alloc_rootdomain(void)
 {
         struct root_domain *rd;
 
@@ -5898,7 +5905,7 @@ static struct root_domain *alloc_rootdomain(const cpumask_t *map)
         if (!rd)
                 return NULL;
 
-        init_rootdomain(rd, map);
+        init_rootdomain(rd);
 
         return rd;
 }
@@ -6319,7 +6326,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
         sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
 #endif
 
-        rd = alloc_rootdomain(cpu_map);
+        rd = alloc_rootdomain();
         if (!rd) {
                 printk(KERN_WARNING "Cannot alloc root domain\n");
                 return -ENOMEM;
@@ -6894,7 +6901,6 @@ void __init sched_init(void)
 #ifdef CONFIG_SMP
                 rq->sd = NULL;
                 rq->rd = NULL;
-                rq_attach_root(rq, &def_root_domain);
                 rq->active_balance = 0;
                 rq->next_balance = jiffies;
                 rq->push_cpu = 0;
@@ -6903,6 +6909,7 @@ void __init sched_init(void)
                 INIT_LIST_HEAD(&rq->migration_queue);
                 rq->rt.highest_prio = MAX_RT_PRIO;
                 rq->rt.overloaded = 0;
+                rq_attach_root(rq, &def_root_domain);
 #endif
                 atomic_set(&rq->nr_iowait, 0);