Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel:
  sched: tune multi-core idle balancing
  sched: retune wake granularity
  sched: wakeup-buddy tasks are cache-hot
  sched: improve affine wakeups
  sched, net: socket wakeups are sync
  sched: clean up wakeup balancing, code flow
  sched: clean up wakeup balancing, rename variables
  sched: clean up wakeup balancing, move wake_affine()

6 files changed, 134 insertions, 77 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 11d8e9a74eff..3625fcaf5d0f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -929,6 +929,9 @@ struct sched_entity {
         u64                     vruntime;
         u64                     prev_sum_exec_runtime;
 
+        u64                     last_wakeup;
+        u64                     avg_overlap;
+
 #ifdef CONFIG_SCHEDSTATS
         u64                     wait_start;
         u64                     wait_max;
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 2352f46160d3..2d8dac8799cf 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -138,7 +138,6 @@
                                 | SD_BALANCE_FORK       \
                                 | SD_BALANCE_EXEC       \
                                 | SD_WAKE_AFFINE        \
-                                | SD_WAKE_IDLE          \
                                 | SD_SHARE_PKG_RESOURCES\
                                 | BALANCE_FOR_MC_POWER, \
         .last_balance           = jiffies,              \
diff --git a/kernel/sched.c b/kernel/sched.c
index d1ad69b270ca..3f7c5eb254e2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1396,6 +1396,12 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
 {
         s64 delta;
 
+        /*
+         * Buddy candidates are cache hot:
+         */
+        if (&p->se == cfs_rq_of(&p->se)->next)
+                return 1;
+
         if (p->sched_class != &fair_sched_class)
                 return 0;
 
@@ -1855,10 +1861,11 @@ out_activate:
                 schedstat_inc(p, se.nr_wakeups_remote);
         update_rq_clock(rq);
         activate_task(rq, p, 1);
-        check_preempt_curr(rq, p);
         success = 1;
 
 out_running:
+        check_preempt_curr(rq, p);
+
         p->state = TASK_RUNNING;
 #ifdef CONFIG_SMP
         if (p->sched_class->task_wake_up)
@@ -1892,6 +1899,8 @@ static void __sched_fork(struct task_struct *p)
         p->se.exec_start                = 0;
         p->se.sum_exec_runtime          = 0;
         p->se.prev_sum_exec_runtime     = 0;
+        p->se.last_wakeup               = 0;
+        p->se.avg_overlap               = 0;
 
 #ifdef CONFIG_SCHEDSTATS
         p->se.wait_start                = 0;
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 4b5e24cf2f4a..ef358ba07683 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -288,6 +288,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
         PN(se.exec_start);
         PN(se.vruntime);
         PN(se.sum_exec_runtime);
+        PN(se.avg_overlap);
 
         nr_switches = p->nvcsw + p->nivcsw;
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index f2cc59080efa..b85cac4b5e25 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -73,13 +73,13 @@ unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL;
 
 /*
  * SCHED_OTHER wake-up granularity.
- * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ * (default: 5 msec * (1 + ilog(ncpus)), units: nanoseconds)
  *
  * This option delays the preemption effects of decoupled workloads
  * and reduces their over-scheduling. Synchronous workloads will still
  * have immediate wakeup/sleep latencies.
  */
-unsigned int sysctl_sched_wakeup_granularity = 10000000UL;
+unsigned int sysctl_sched_wakeup_granularity = 5000000UL;
 
 const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
 
@@ -556,6 +556,21 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
         account_entity_enqueue(cfs_rq, se);
 }
 
+static void update_avg(u64 *avg, u64 sample)
+{
+        s64 diff = sample - *avg;
+        *avg += diff >> 3;
+}
+
+static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+        if (!se->last_wakeup)
+                return;
+
+        update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup);
+        se->last_wakeup = 0;
+}
+
 static void
 dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 {
@@ -566,6 +581,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 
         update_stats_dequeue(cfs_rq, se);
         if (sleep) {
+                update_avg_stats(cfs_rq, se);
 #ifdef CONFIG_SCHEDSTATS
                 if (entity_is_task(se)) {
                         struct task_struct *tsk = task_of(se);
@@ -980,96 +996,121 @@ static inline int wake_idle(int cpu, struct task_struct *p)
 #endif
 
 #ifdef CONFIG_SMP
-static int select_task_rq_fair(struct task_struct *p, int sync)
+
+static const struct sched_class fair_sched_class;
+
+static int
+wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq,
+            struct task_struct *p, int prev_cpu, int this_cpu, int sync,
+            int idx, unsigned long load, unsigned long this_load,
+            unsigned int imbalance)
 {
-        int cpu, this_cpu;
-        struct rq *rq;
-        struct sched_domain *sd, *this_sd = NULL;
-        int new_cpu;
+        struct task_struct *curr = this_rq->curr;
+        unsigned long tl = this_load;
+        unsigned long tl_per_task;
+
+        if (!(this_sd->flags & SD_WAKE_AFFINE))
+                return 0;
+
+        /*
+         * If the currently running task will sleep within
+         * a reasonable amount of time then attract this newly
+         * woken task:
+         */
+        if (sync && curr->sched_class == &fair_sched_class) {
+                if (curr->se.avg_overlap < sysctl_sched_migration_cost &&
+                                p->se.avg_overlap < sysctl_sched_migration_cost)
+                        return 1;
+        }
 
-        cpu      = task_cpu(p);
-        rq       = task_rq(p);
-        this_cpu = smp_processor_id();
-        new_cpu  = cpu;
+        schedstat_inc(p, se.nr_wakeups_affine_attempts);
+        tl_per_task = cpu_avg_load_per_task(this_cpu);
 
-        if (cpu == this_cpu)
-                goto out_set_cpu;
+        /*
+         * If sync wakeup then subtract the (maximum possible)
+         * effect of the currently running task from the load
+         * of the current CPU:
+         */
+        if (sync)
+                tl -= current->se.load.weight;
+
+        if ((tl <= load && tl + target_load(prev_cpu, idx) <= tl_per_task) ||
+                        100*(tl + p->se.load.weight) <= imbalance*load) {
+                /*
+                 * This domain has SD_WAKE_AFFINE and
+                 * p is cache cold in this domain, and
+                 * there is no bad imbalance.
+                 */
+                schedstat_inc(this_sd, ttwu_move_affine);
+                schedstat_inc(p, se.nr_wakeups_affine);
 
+                return 1;
+        }
+        return 0;
+}
+
+static int select_task_rq_fair(struct task_struct *p, int sync)
+{
+        struct sched_domain *sd, *this_sd = NULL;
+        int prev_cpu, this_cpu, new_cpu;
+        unsigned long load, this_load;
+        struct rq *rq, *this_rq;
+        unsigned int imbalance;
+        int idx;
+
+        prev_cpu        = task_cpu(p);
+        rq              = task_rq(p);
+        this_cpu        = smp_processor_id();
+        this_rq         = cpu_rq(this_cpu);
+        new_cpu         = prev_cpu;
+
+        /*
+         * 'this_sd' is the first domain that both
+         * this_cpu and prev_cpu are present in:
+         */
         for_each_domain(this_cpu, sd) {
-                if (cpu_isset(cpu, sd->span)) {
+                if (cpu_isset(prev_cpu, sd->span)) {
                         this_sd = sd;
                         break;
                 }
         }
 
         if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
-                goto out_set_cpu;
+                goto out;
 
         /*
          * Check for affine wakeup and passive balancing possibilities.
          */
-        if (this_sd) {
-                int idx = this_sd->wake_idx;
-                unsigned int imbalance;
-                unsigned long load, this_load;
-
-                imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
-
-                load = source_load(cpu, idx);
-                this_load = target_load(this_cpu, idx);
-
-                new_cpu = this_cpu; /* Wake to this CPU if we can */
-
-                if (this_sd->flags & SD_WAKE_AFFINE) {
-                        unsigned long tl = this_load;
-                        unsigned long tl_per_task;
-
-                        /*
-                         * Attract cache-cold tasks on sync wakeups:
-                         */
-                        if (sync && !task_hot(p, rq->clock, this_sd))
-                                goto out_set_cpu;
-
-                        schedstat_inc(p, se.nr_wakeups_affine_attempts);
-                        tl_per_task = cpu_avg_load_per_task(this_cpu);
-
-                        /*
-                         * If sync wakeup then subtract the (maximum possible)
-                         * effect of the currently running task from the load
-                         * of the current CPU:
-                         */
-                        if (sync)
-                                tl -= current->se.load.weight;
-
-                        if ((tl <= load &&
-                                tl + target_load(cpu, idx) <= tl_per_task) ||
-                               100*(tl + p->se.load.weight) <= imbalance*load) {
-                                /*
-                                 * This domain has SD_WAKE_AFFINE and
-                                 * p is cache cold in this domain, and
-                                 * there is no bad imbalance.
-                                 */
-                                schedstat_inc(this_sd, ttwu_move_affine);
-                                schedstat_inc(p, se.nr_wakeups_affine);
-                                goto out_set_cpu;
-                        }
-                }
+        if (!this_sd)
+                goto out;
 
-                /*
-                 * Start passive balancing when half the imbalance_pct
-                 * limit is reached.
-                 */
-                if (this_sd->flags & SD_WAKE_BALANCE) {
-                        if (imbalance*this_load <= 100*load) {
-                                schedstat_inc(this_sd, ttwu_move_balance);
-                                schedstat_inc(p, se.nr_wakeups_passive);
-                                goto out_set_cpu;
-                        }
+        idx = this_sd->wake_idx;
+
+        imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
+
+        load = source_load(prev_cpu, idx);
+        this_load = target_load(this_cpu, idx);
+
+        if (wake_affine(rq, this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx,
+                                     load, this_load, imbalance))
+                return this_cpu;
+
+        if (prev_cpu == this_cpu)
+                goto out;
+
+        /*
+         * Start passive balancing when half the imbalance_pct
+         * limit is reached.
+         */
+        if (this_sd->flags & SD_WAKE_BALANCE) {
+                if (imbalance*this_load <= 100*load) {
+                        schedstat_inc(this_sd, ttwu_move_balance);
+                        schedstat_inc(p, se.nr_wakeups_passive);
+                        return this_cpu;
                 }
         }
 
-        new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
-out_set_cpu:
+out:
         return wake_idle(new_cpu, p);
 }
 #endif /* CONFIG_SMP */
@@ -1092,6 +1133,10 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
                 return;
         }
 
+        se->last_wakeup = se->sum_exec_runtime;
+        if (unlikely(se == pse))
+                return;
+
         cfs_rq_of(pse)->next = pse;
 
         /*
diff --git a/net/core/sock.c b/net/core/sock.c
index 09cb3a74de7f..2654c147c004 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1621,7 +1621,7 @@ static void sock_def_readable(struct sock *sk, int len)
 {
         read_lock(&sk->sk_callback_lock);
         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
-                wake_up_interruptible(sk->sk_sleep);
+                wake_up_interruptible_sync(sk->sk_sleep);
         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
         read_unlock(&sk->sk_callback_lock);
 }
@@ -1635,7 +1635,7 @@ static void sock_def_write_space(struct sock *sk)
          */
         if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
                 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
-                        wake_up_interruptible(sk->sk_sleep);
+                        wake_up_interruptible_sync(sk->sk_sleep);
 
                 /* Should agree with poll, otherwise some programs break */
                 if (sock_writeable(sk))