Dear RT Folks,

I'm pleased to announce the 3.0.7-rt20 release.

3.0.7-rt19 is an not announced intermediate release, which only
updates to 3.0.7. No rt changes except dropping patches which made it
into 3.0.7.

Changes from 3.0.7-rt19 to 3.0.7-rt20

 * Fix a long standing RT throttling problem with cgroups and
   RT_GROUP_SCHED (Peter Zijlstra, Thanks to Carsten Emde for
   providing the debug information!)

 * Minor fixes (Yong Zhang)

Delta patch against 3.0.7-rt19

 https://tglx.de/~tglx/rt/patch-3.0.7-rt19-rt20.patch.gz

also appended below.


Patch against 3.0.7 can be found here:

 https://tglx.de/~tglx/rt/patch-3.0.7-rt20.patch.gz


The split quilt queue is available at:

 https://tglx.de/~tglx/rt/patches-3.0.7-rt20.tar.gz

Known issues:

 Yong discovered a non critical cpuhotplug problem, which needs some
 more thought. Will try to address that in the next days as traveling
 allows (about to head to Prague for a long RTLWS/KS/LinuxCon/ELCE
 week).

Enjoy,

       tglx

--------------->
Index: linux-2.6/kernel/cpu.c
===================================================================

--- linux-2.6.orig/kernel/cpu.c
+++ linux-2.6/kernel/cpu.c

@@ -139,7 +139,7 @@ static int cpu_unplug_begin(unsigned int

       struct task_struct *tsk;

       init_completion(&hp->synced);
-       tsk = kthread_create(sync_unplug_thread, hp, "sync_unplug/%d\n", cpu);
+       tsk = kthread_create(sync_unplug_thread, hp, "sync_unplug/%d", cpu);
       if (IS_ERR(tsk))
               return (PTR_ERR(tsk));
       kthread_bind(tsk, cpu);
Index: linux-2.6/kernel/printk.c
===================================================================

--- linux-2.6.orig/kernel/printk.c
+++ linux-2.6/kernel/printk.c

@@ -1282,8 +1282,8 @@ void printk_tick(void)

 int printk_needs_cpu(int cpu)
 {
-       if (cpu_is_offline(cpu))
-               printk_tick();
+       if (unlikely(cpu_is_offline(cpu)))
+               __this_cpu_write(printk_pending, 0);
       return __this_cpu_read(printk_pending);
 }

Index: linux-2.6/kernel/sched_rt.c
===================================================================

--- linux-2.6.orig/kernel/sched_rt.c
+++ linux-2.6/kernel/sched_rt.c

@@ -556,12 +556,9 @@ static inline int balance_runtime(struct

 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 {
-       int i, idle = 1;
+       int i, idle = 1, throttled = 0;
       const struct cpumask *span;

-       if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
-               return 1;
-
       span = sched_rt_period_mask();
       for_each_cpu(i, span) {
               int enqueue = 0;

@@ -596,12 +593,17 @@ static int do_sched_rt_period_timer(stru

                       if (!rt_rq_throttled(rt_rq))
                               enqueue = 1;
               }
+               if (rt_rq->rt_throttled)
+                       throttled = 1;

               if (enqueue)
                       sched_rt_rq_enqueue(rt_rq);
               raw_spin_unlock(&rq->lock);
       }

+       if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
+               return 1;
+
       return idle;
 }

@@ -633,8 +635,24 @@ static int sched_rt_runtime_exceeded(str

               return 0;

       if (rt_rq->rt_time > runtime) {
-               rt_rq->rt_throttled = 1;
-               printk_once(KERN_WARNING "sched: RT throttling activated\n");
+               struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+               /*
+                * Don't actually throttle groups that have no runtime assigned
+                * but accrue some time due to boosting.
+                */
+               if (likely(rt_b->rt_runtime)) {
+                       rt_rq->rt_throttled = 1;
+                       printk_once(KERN_WARNING "sched: RT throttling activated\n");
+               } else {
+                       /*
+                        * In case we did anyway, make it go away,
+                        * replenishment is a joke, since it will replenish us
+                        * with exactly 0 ns.
+                        */
+                       rt_rq->rt_time = 0;
+               }
+
               if (rt_rq_throttled(rt_rq)) {
                       sched_rt_rq_dequeue(rt_rq);
                       return 1;

@@ -662,7 +680,8 @@ static void update_curr_rt(struct rq *rq

       if (unlikely((s64)delta_exec < 0))
               delta_exec = 0;

-       schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec));
+       schedstat_set(curr->se.statistics.exec_max,
+                     max(curr->se.statistics.exec_max, delta_exec));

       curr->se.sum_exec_runtime += delta_exec;
       account_group_exec_runtime(curr, delta_exec);
Index: linux-2.6/kernel/workqueue.c
===================================================================

--- linux-2.6.orig/kernel/workqueue.c
+++ linux-2.6/kernel/workqueue.c

@@ -3274,14 +3274,14 @@ static void flush_gcwq(struct global_cwq

       spin_unlock_irq(&gcwq->lock);

-       gcwq = get_gcwq(get_cpu());
+       gcwq = get_gcwq(get_cpu_light());
       spin_lock_irq(&gcwq->lock);
       list_for_each_entry_safe(work, nw, &non_affine_works, entry) {
               list_del_init(&work->entry);
               ___queue_work(get_work_cwq(work)->wq, gcwq, work);
       }
       spin_unlock_irq(&gcwq->lock);
-       put_cpu();
+       put_cpu_light();
 }

 static int __devinit workqueue_cpu_down_callback(struct notifier_block *nfb,
Index: linux-2.6/localversion-rt
===================================================================

--- linux-2.6.orig/localversion-rt
+++ linux-2.6/localversion-rt

@@ -1 +1 @@
--rt19
+-rt20
--

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