Merge tag 'v3.6' into staging/for_v3.7

Linux 3.6

* tag 'v3.6': (562 commits)
  Linux 3.6
  vfs: dcache: fix deadlock in tree traversal
  mtdchar: fix offset overflow detection
  thp: avoid VM_BUG_ON page_count(page) false positives in __collapse_huge_page_copy
  iommu/amd: Fix wrong assumption in iommu-group specific code
  netdev: octeon: fix return value check in octeon_mgmt_init_phy()
  ALSA: snd-usb: fix next_packet_size calls for pause case
  inetpeer: fix token initialization
  qlcnic: Fix scheduling while atomic bug
  bnx2: Clean up remaining iounmap
  trivial select_parent documentation fix
  net: phy: smsc: Implement PHY config_init for LAN87xx
  smsc75xx: fix resume after device reset
  um: Preinclude include/linux/kern_levels.h
  um: Fix IPC on um
  netdev: pasemi: fix return value check in pasemi_mac_phy_init()
  team: fix return value check
  l2tp: fix return value check
  USB: Fix race condition when removing host controllers
  USB: ohci-at91: fix null pointer in ohci_hcd_at91_overcurrent_irq
  ...

1 files changed, 11 insertions, 62 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fbf1fd0..649c9f8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5304,27 +5304,17 @@ void idle_task_exit(void)
 }
 
 /*
- * While a dead CPU has no uninterruptible tasks queued at this point,
- * it might still have a nonzero ->nr_uninterruptible counter, because
- * for performance reasons the counter is not stricly tracking tasks to
- * their home CPUs. So we just add the counter to another CPU's counter,
- * to keep the global sum constant after CPU-down:
- */
-static void migrate_nr_uninterruptible(struct rq *rq_src)
-{
-	struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
-
-	rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
-	rq_src->nr_uninterruptible = 0;
-}
-
-/*
- * remove the tasks which were accounted by rq from calc_load_tasks.
+ * Since this CPU is going 'away' for a while, fold any nr_active delta
+ * we might have. Assumes we're called after migrate_tasks() so that the
+ * nr_active count is stable.
+ *
+ * Also see the comment "Global load-average calculations".
  */
-static void calc_global_load_remove(struct rq *rq)
+static void calc_load_migrate(struct rq *rq)
 {
-	atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
-	rq->calc_load_active = 0;
+	long delta = calc_load_fold_active(rq);
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
 }
 
 /*
@@ -5352,9 +5342,6 @@ static void migrate_tasks(unsigned int dead_cpu)
 	 */
 	rq->stop = NULL;
 
-	/* Ensure any throttled groups are reachable by pick_next_task */
-	unthrottle_offline_cfs_rqs(rq);
-
 	for ( ; ; ) {
 		/*
 		 * There's this thread running, bail when that's the only
@@ -5618,8 +5605,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
 		BUG_ON(rq->nr_running != 1); /* the migration thread */
 		raw_spin_unlock_irqrestore(&rq->lock, flags);
 
-		migrate_nr_uninterruptible(rq);
-		calc_global_load_remove(rq);
+		calc_load_migrate(rq);
 		break;
 #endif
 	}
@@ -6028,11 +6014,6 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu)
  * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
  * allows us to avoid some pointer chasing select_idle_sibling().
  *
- * Iterate domains and sched_groups downward, assigning CPUs to be
- * select_idle_sibling() hw buddy.  Cross-wiring hw makes bouncing
- * due to random perturbation self canceling, ie sw buddies pull
- * their counterpart to their CPU's hw counterpart.
- *
  * Also keep a unique ID per domain (we use the first cpu number in
  * the cpumask of the domain), this allows us to quickly tell if
  * two cpus are in the same cache domain, see cpus_share_cache().
@@ -6046,40 +6027,8 @@ static void update_top_cache_domain(int cpu)
 	int id = cpu;
 
 	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
-	if (sd) {
-		struct sched_domain *tmp = sd;
-		struct sched_group *sg, *prev;
-		bool right;
-
-		/*
-		 * Traverse to first CPU in group, and count hops
-		 * to cpu from there, switching direction on each
-		 * hop, never ever pointing the last CPU rightward.
-		 */
-		do {
-			id = cpumask_first(sched_domain_span(tmp));
-			prev = sg = tmp->groups;
-			right = 1;
-
-			while (cpumask_first(sched_group_cpus(sg)) != id)
-				sg = sg->next;
-
-			while (!cpumask_test_cpu(cpu, sched_group_cpus(sg))) {
-				prev = sg;
-				sg = sg->next;
-				right = !right;
-			}
-
-			/* A CPU went down, never point back to domain start. */
-			if (right && cpumask_first(sched_group_cpus(sg->next)) == id)
-				right = false;
-
-			sg = right ? sg->next : prev;
-			tmp->idle_buddy = cpumask_first(sched_group_cpus(sg));
-		} while ((tmp = tmp->child));
-
+	if (sd)
 		id = cpumask_first(sched_domain_span(sd));
-	}
 
 	rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
 	per_cpu(sd_llc_id, cpu) = id;