Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Two scheduler debugging fixes"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix 'schedstats=enable' cmdline option
  sched/debug: Fix /proc/sched_debug regression

3 files changed, 28 insertions, 16 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7f2cae4620c7..385c947482e1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2253,9 +2253,11 @@ int sysctl_numa_balancing(struct ctl_table *table, int write,
 #endif
 #endif
 
+#ifdef CONFIG_SCHEDSTATS
+
 DEFINE_STATIC_KEY_FALSE(sched_schedstats);
+static bool __initdata __sched_schedstats = false;
 
-#ifdef CONFIG_SCHEDSTATS
 static void set_schedstats(bool enabled)
 {
         if (enabled)
@@ -2278,11 +2280,16 @@ static int __init setup_schedstats(char *str)
         if (!str)
                 goto out;
 
+        /*
+         * This code is called before jump labels have been set up, so we can't
+         * change the static branch directly just yet.  Instead set a temporary
+         * variable so init_schedstats() can do it later.
+         */
         if (!strcmp(str, "enable")) {
-                set_schedstats(true);
+                __sched_schedstats = true;
                 ret = 1;
         } else if (!strcmp(str, "disable")) {
-                set_schedstats(false);
+                __sched_schedstats = false;
                 ret = 1;
         }
 out:
@@ -2293,6 +2300,11 @@ out:
 }
 __setup("schedstats=", setup_schedstats);
 
+static void __init init_schedstats(void)
+{
+        set_schedstats(__sched_schedstats);
+}
+
 #ifdef CONFIG_PROC_SYSCTL
 int sysctl_schedstats(struct ctl_table *table, int write,
                          void __user *buffer, size_t *lenp, loff_t *ppos)
@@ -2313,8 +2325,10 @@ int sysctl_schedstats(struct ctl_table *table, int write,
                 set_schedstats(state);
         return err;
 }
-#endif
-#endif
+#endif /* CONFIG_PROC_SYSCTL */
+#else  /* !CONFIG_SCHEDSTATS */
+static inline void init_schedstats(void) {}
+#endif /* CONFIG_SCHEDSTATS */
 
 /*
  * fork()/clone()-time setup:
@@ -7487,6 +7501,8 @@ void __init sched_init(void)
 #endif
         init_sched_fair_class();
 
+        init_schedstats();
+
         scheduler_running = 1;
 }
 
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index cf905f655ba1..0368c393a336 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -427,19 +427,12 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
                 SPLIT_NS(p->se.vruntime),
                 (long long)(p->nvcsw + p->nivcsw),
                 p->prio);
-#ifdef CONFIG_SCHEDSTATS
-        if (schedstat_enabled()) {
-                SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld",
-                        SPLIT_NS(p->se.statistics.wait_sum),
-                        SPLIT_NS(p->se.sum_exec_runtime),
-                        SPLIT_NS(p->se.statistics.sum_sleep_runtime));
-        }
-#else
+
         SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld",
-                0LL, 0L,
+                SPLIT_NS(schedstat_val(p, se.statistics.wait_sum)),
                 SPLIT_NS(p->se.sum_exec_runtime),
-                0LL, 0L);
-#endif
+                SPLIT_NS(schedstat_val(p, se.statistics.sum_sleep_runtime)));
+
 #ifdef CONFIG_NUMA_BALANCING
         SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
 #endif
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 70b3b6a20fb0..78955cbea31c 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -33,6 +33,8 @@ rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
 # define schedstat_inc(rq, field)       do { if (schedstat_enabled()) { (rq)->field++; } } while (0)
 # define schedstat_add(rq, field, amt)  do { if (schedstat_enabled()) { (rq)->field += (amt); } } while (0)
 # define schedstat_set(var, val)        do { if (schedstat_enabled()) { var = (val); } } while (0)
+# define schedstat_val(rq, field)       ((schedstat_enabled()) ? (rq)->field : 0)
+
 #else /* !CONFIG_SCHEDSTATS */
 static inline void
 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
@@ -47,6 +49,7 @@ rq_sched_info_depart(struct rq *rq, unsigned long long delta)
 # define schedstat_inc(rq, field)       do { } while (0)
 # define schedstat_add(rq, field, amt)  do { } while (0)
 # define schedstat_set(var, val)        do { } while (0)
+# define schedstat_val(rq, field)       0
 #endif
 
 #ifdef CONFIG_SCHED_INFO