Merge branch 'sched/urgent' into sched/core

Merge in fixes before we queue up dependent bits, to avoid conflicts.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

5 files changed, 20 insertions, 70 deletions

diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
index 0984a21076a3..0f1bacb005a4 100644
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -110,6 +110,9 @@ out_fail:
 
 bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
 {
+        if (!sysctl_sched_autogroup_enabled)
+                return false;
+
         if (tg != &root_task_group)
                 return false;
 
@@ -143,15 +146,11 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag)
 
         p->signal->autogroup = autogroup_kref_get(ag);
 
-        if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))
-                goto out;
-
         t = p;
         do {
                 sched_move_task(t);
         } while_each_thread(p, t);
 
-out:
         unlock_task_sighand(p, &flags);
         autogroup_kref_put(prev);
 }
@@ -159,8 +158,11 @@ out:
 /* Allocates GFP_KERNEL, cannot be called under any spinlock */
 void sched_autogroup_create_attach(struct task_struct *p)
 {
-        struct autogroup *ag = autogroup_create();
+        struct autogroup *ag;
 
+        if (!sysctl_sched_autogroup_enabled)
+                return;
+        ag = autogroup_create();
         autogroup_move_group(p, ag);
         /* drop extra reference added by autogroup_create() */
         autogroup_kref_put(ag);
@@ -176,11 +178,15 @@ EXPORT_SYMBOL(sched_autogroup_detach);
 
 void sched_autogroup_fork(struct signal_struct *sig)
 {
+        if (!sysctl_sched_autogroup_enabled)
+                return;
         sig->autogroup = autogroup_task_get(current);
 }
 
 void sched_autogroup_exit(struct signal_struct *sig)
 {
+        if (!sysctl_sched_autogroup_enabled)
+                return;
         autogroup_kref_put(sig->autogroup);
 }
 
@@ -193,58 +199,6 @@ static int __init setup_autogroup(char *str)
 
 __setup("noautogroup", setup_autogroup);
 
-#ifdef CONFIG_PROC_FS
-
-int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
-{
-        static unsigned long next = INITIAL_JIFFIES;
-        struct autogroup *ag;
-        int err;
-
-        if (nice < -20 || nice > 19)
-                return -EINVAL;
-
-        err = security_task_setnice(current, nice);
-        if (err)
-                return err;
-
-        if (nice < 0 && !can_nice(current, nice))
-                return -EPERM;
-
-        /* this is a heavy operation taking global locks.. */
-        if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
-                return -EAGAIN;
-
-        next = HZ / 10 + jiffies;
-        ag = autogroup_task_get(p);
-
-        down_write(&ag->lock);
-        err = sched_group_set_shares(ag->tg, prio_to_weight[nice + 20]);
-        if (!err)
-                ag->nice = nice;
-        up_write(&ag->lock);
-
-        autogroup_kref_put(ag);
-
-        return err;
-}
-
-void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
-{
-        struct autogroup *ag = autogroup_task_get(p);
-
-        if (!task_group_is_autogroup(ag->tg))
-                goto out;
-
-        down_read(&ag->lock);
-        seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
-        up_read(&ag->lock);
-
-out:
-        autogroup_kref_put(ag);
-}
-#endif /* CONFIG_PROC_FS */
-
 #ifdef CONFIG_SCHED_DEBUG
 int autogroup_path(struct task_group *tg, char *buf, int buflen)
 {
diff --git a/kernel/sched/auto_group.h b/kernel/sched/auto_group.h
index 8bd047142816..4552c6bf79d2 100644
--- a/kernel/sched/auto_group.h
+++ b/kernel/sched/auto_group.h
@@ -4,11 +4,6 @@
 #include <linux/rwsem.h>
 
 struct autogroup {
-        /*
-         * reference doesn't mean how many thread attach to this
-         * autogroup now. It just stands for the number of task
-         * could use this autogroup.
-         */
         struct kref             kref;
         struct task_group       *tg;
         struct rw_semaphore     lock;
@@ -29,9 +24,7 @@ extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg);
 static inline struct task_group *
 autogroup_task_group(struct task_struct *p, struct task_group *tg)
 {
-        int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
-
-        if (enabled && task_wants_autogroup(p, tg))
+        if (task_wants_autogroup(p, tg))
                 return p->signal->autogroup->tg;
 
         return tg;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a319d56c7605..59e072b2db97 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3330,7 +3330,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
          * Batch and idle tasks do not preempt non-idle tasks (their preemption
          * is driven by the tick):
          */
-        if (unlikely(p->policy != SCHED_NORMAL))
+        if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION))
                 return;
 
         find_matching_se(&se, &pse);
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index eebefcad7027..e68e69ab917d 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -32,6 +32,11 @@ SCHED_FEAT(LAST_BUDDY, true)
 SCHED_FEAT(CACHE_HOT_BUDDY, true)
 
 /*
+ * Allow wakeup-time preemption of the current task:
+ */
+SCHED_FEAT(WAKEUP_PREEMPTION, true)
+
+/*
  * Use arch dependent cpu power functions
  */
 SCHED_FEAT(ARCH_POWER, true)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 26f65eaa01f9..b0fa5ad09873 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -367,10 +367,8 @@ static struct ctl_table kern_table[] = {
                 .procname       = "sched_autogroup_enabled",
                 .data           = &sysctl_sched_autogroup_enabled,
                 .maxlen         = sizeof(unsigned int),
-                .mode           = 0644,
-                .proc_handler   = proc_dointvec_minmax,
-                .extra1         = &zero,
-                .extra2         = &one,
+                .mode           = 0444,
+                .proc_handler   = proc_dointvec,
         },
 #endif
 #ifdef CONFIG_CFS_BANDWIDTH