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>

diff --git a/kernel/sched.c b/kernel/sched.c
index 5834c7fb79a5d45529fb2582e91121e5d61034b8..02d468844a91b79beb4975499a80d9703eaee9e2 100644 (file)
--- 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);