[ANNOUNCE] 3.2.50-rt71

From: Steven Rostedt
Date: Wed Sep 11 2013 - 21:08:58 EST



Dear RT Folks,

I'm pleased to announce the 3.2.50-rt71 stable release.


You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

branch: v3.2-rt
Head SHA1: ce97f8430a19c032746d72f1addbc03c57acdce6


Or to build 3.2.50-rt71 directly, the following patches should be applied:

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.2.tar.xz

http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.2.50.xz

http://www.kernel.org/pub/linux/kernel/projects/rt/3.2/patch-3.2.50-rt71.patch.xz



You can also build from 3.2.50-rt70 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.2/incr/patch-3.2.50-rt70-rt71.patch.xz



Enjoy,

-- Steve


Changes from v3.2.50-rt70:

---

Ivo Sieben (1):
genirq: Set irq thread to RT priority on creation

Mike Galbraith (1):
x86/mce: fix mce timer interval

Paul Gortmaker (1):
list_bl.h: make list head locking RT safe

Sebastian Andrzej Siewior (4):
kernel/cpu: fix cpu down problem if kthread's cpu is going down
kernel/hotplug: restore original cpu mask oncpu/down
drm/i915: drop trace_i915_gem_ring_dispatch on rt
genirq: do not invoke the affinity callback via a workqueue

Steven Rostedt (5):
sched/workqueue: Only wake up idle workers if not blocked on sleeping spin lock
rt,ntp: Move call to schedule_delayed_work() to helper thread
hwlat-detector: Update hwlat_detector to add outer loop detection
hwlat-detector: Use trace_clock_local if available
hwlat-detector: Use thread instead of stop machine

Steven Rostedt (Red Hat) (2):
hwlat-detect/trace: Export trace_clock_local for hwlat-detector
Linux 3.2.50-rt71

Uwe Kleine-KÃnig (1):
list_bl.h: fix it for for !SMP && !DEBUG_SPINLOCK

Zhao Hongjiang (1):
timers: prepare for full preemption improve

----
arch/x86/kernel/cpu/mcheck/mce.c | 4 +-
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 2 +
drivers/misc/hwlat_detector.c | 117 +++++++++++++++++-----------
include/linux/interrupt.h | 1 +
include/linux/list_bl.h | 28 ++++++-
kernel/cpu.c | 29 ++++++-
kernel/irq/manage.c | 89 +++++++++++++++++++--
kernel/sched.c | 4 +-
kernel/time/ntp.c | 42 ++++++++++
kernel/timer.c | 8 +-
kernel/trace/trace_clock.c | 1 +
localversion-rt | 2 +-
12 files changed, 264 insertions(+), 63 deletions(-)
---------------------------
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 8ceb100..b08a373 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1139,7 +1139,7 @@ static enum hrtimer_restart mce_start_timer(struct hrtimer *timer)
*n = min(*n*2, round_jiffies_relative(check_interval*HZ));

hrtimer_forward(timer, timer->base->get_time(),
- ns_to_ktime(jiffies_to_usecs(*n) * 1000));
+ ns_to_ktime(jiffies_to_usecs(*n) * 1000ULL));
return HRTIMER_RESTART;
}

@@ -1435,7 +1435,7 @@ static void __mcheck_cpu_init_timer(void)
if (!*n)
return;

- hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(*n) * 1000),
+ hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(*n) * 1000ULL),
0 , HRTIMER_MODE_REL_PINNED);
}

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index b1bb734..8bef4a5 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1216,7 +1216,9 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
dev_priv->relative_constants_mode = mode;
}

+#ifndef CONFIG_PREEMPT_RT_BASE
trace_i915_gem_ring_dispatch(ring, seqno);
+#endif

exec_start = batch_obj->gtt_offset + args->batch_start_offset;
exec_len = args->batch_len;
diff --git a/drivers/misc/hwlat_detector.c b/drivers/misc/hwlat_detector.c
index b7b7c90..6f61d5f 100644
--- a/drivers/misc/hwlat_detector.c
+++ b/drivers/misc/hwlat_detector.c
@@ -41,7 +41,6 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/ring_buffer.h>
-#include <linux/stop_machine.h>
#include <linux/time.h>
#include <linux/hrtimer.h>
#include <linux/kthread.h>
@@ -51,6 +50,7 @@
#include <linux/version.h>
#include <linux/delay.h>
#include <linux/slab.h>
+#include <linux/trace_clock.h>

#define BUF_SIZE_DEFAULT 262144UL /* 8K*(sizeof(entry)) */
#define BUF_FLAGS (RB_FL_OVERWRITE) /* no block on full */
@@ -106,7 +106,6 @@ struct data; /* Global state */
/* Sampling functions */
static int __buffer_add_sample(struct sample *sample);
static struct sample *buffer_get_sample(struct sample *sample);
-static int get_sample(void *unused);

/* Threading and state */
static int kthread_fn(void *unused);
@@ -143,11 +142,12 @@ static void detector_exit(void);
struct sample {
u64 seqnum; /* unique sequence */
u64 duration; /* ktime delta */
+ u64 outer_duration; /* ktime delta (outer loop) */
struct timespec timestamp; /* wall time */
unsigned long lost;
};

-/* keep the global state somewhere. Mostly used under stop_machine. */
+/* keep the global state somewhere. */
static struct data {

struct mutex lock; /* protect changes */
@@ -170,7 +170,7 @@ static struct data {
* @sample: The new latency sample value
*
* This receives a new latency sample and records it in a global ring buffer.
- * No additional locking is used in this case - suited for stop_machine use.
+ * No additional locking is used in this case.
*/
static int __buffer_add_sample(struct sample *sample)
{
@@ -210,29 +210,60 @@ static struct sample *buffer_get_sample(struct sample *sample)
return sample;
}

+#ifndef CONFIG_TRACING
+#define time_type ktime_t
+#define time_get() ktime_get()
+#define time_to_us(x) ktime_to_us(x)
+#define time_sub(a, b) ktime_sub(a, b)
+#define init_time(a, b) (a).tv64 = b
+#define time_u64(a) (a).tv64
+#else
+#define time_type u64
+#define time_get() trace_clock_local()
+#define time_to_us(x) div_u64(x, 1000)
+#define time_sub(a, b) ((a) - (b))
+#define init_time(a, b) a = b
+#define time_u64(a) a
+#endif
/**
* get_sample - sample the CPU TSC and look for likely hardware latencies
- * @unused: This is not used but is a part of the stop_machine API
*
* Used to repeatedly capture the CPU TSC (or similar), looking for potential
- * hardware-induced latency. Called under stop_machine, with data.lock held.
+ * hardware-induced latency. Called with interrupts disabled and with data.lock held.
*/
-static int get_sample(void *unused)
+static int get_sample(void)
{
- ktime_t start, t1, t2;
+ time_type start, t1, t2, last_t2;
s64 diff, total = 0;
u64 sample = 0;
- int ret = 1;
+ u64 outer_sample = 0;
+ int ret = -1;

- start = ktime_get(); /* start timestamp */
+ init_time(last_t2, 0);
+ start = time_get(); /* start timestamp */

do {

- t1 = ktime_get(); /* we'll look for a discontinuity */
- t2 = ktime_get();
+ t1 = time_get(); /* we'll look for a discontinuity */
+ t2 = time_get();
+
+ if (time_u64(last_t2)) {
+ /* Check the delta from the outer loop (t2 to next t1) */
+ diff = time_to_us(time_sub(t1, last_t2));
+ /* This shouldn't happen */
+ if (diff < 0) {
+ printk(KERN_ERR BANNER "time running backwards\n");
+ goto out;
+ }
+ if (diff > outer_sample)
+ outer_sample = diff;
+ }
+ last_t2 = t2;
+
+ total = time_to_us(time_sub(t2, start)); /* sample width */

- total = ktime_to_us(ktime_sub(t2, start)); /* sample width */
- diff = ktime_to_us(ktime_sub(t2, t1)); /* current diff */
+ /* This checks the inner loop (t1 to t2) */
+ diff = time_to_us(time_sub(t2, t1)); /* current diff */

/* This shouldn't happen */
if (diff < 0) {
@@ -245,13 +276,18 @@ static int get_sample(void *unused)

} while (total <= data.sample_width);

+ ret = 0;
+
/* If we exceed the threshold value, we have found a hardware latency */
- if (sample > data.threshold) {
+ if (sample > data.threshold || outer_sample > data.threshold) {
struct sample s;

+ ret = 1;
+
data.count++;
s.seqnum = data.count;
s.duration = sample;
+ s.outer_duration = outer_sample;
s.timestamp = CURRENT_TIME;
__buffer_add_sample(&s);

@@ -260,7 +296,6 @@ static int get_sample(void *unused)
data.max_sample = sample;
}

- ret = 0;
out:
return ret;
}
@@ -270,32 +305,30 @@ out:
* @unused: A required part of the kthread API.
*
* Used to periodically sample the CPU TSC via a call to get_sample. We
- * use stop_machine, whith does (intentionally) introduce latency since we
+ * disable interrupts, which does (intentionally) introduce latency since we
* need to ensure nothing else might be running (and thus pre-empting).
* Obviously this should never be used in production environments.
*
- * stop_machine will schedule us typically only on CPU0 which is fine for
- * almost every real-world hardware latency situation - but we might later
- * generalize this if we find there are any actualy systems with alternate
- * SMI delivery or other non CPU0 hardware latencies.
+ * Currently this runs on which ever CPU it was scheduled on, but most
+ * real-worald hardware latency situations occur across several CPUs,
+ * but we might later generalize this if we find there are any actualy
+ * systems with alternate SMI delivery or other hardware latencies.
*/
static int kthread_fn(void *unused)
{
- int err = 0;
- u64 interval = 0;
+ int ret;
+ u64 interval;

while (!kthread_should_stop()) {

mutex_lock(&data.lock);

- err = stop_machine(get_sample, unused, 0);
- if (err) {
- /* Houston, we have a problem */
- mutex_unlock(&data.lock);
- goto err_out;
- }
+ local_irq_disable();
+ ret = get_sample();
+ local_irq_enable();

- wake_up(&data.wq); /* wake up reader(s) */
+ if (ret > 0)
+ wake_up(&data.wq); /* wake up reader(s) */

interval = data.sample_window - data.sample_width;
do_div(interval, USEC_PER_MSEC); /* modifies interval value */
@@ -303,15 +336,10 @@ static int kthread_fn(void *unused)
mutex_unlock(&data.lock);

if (msleep_interruptible(interval))
- goto out;
+ break;
}
- goto out;
-err_out:
- printk(KERN_ERR BANNER "could not call stop_machine, disabling\n");
- enabled = 0;
-out:
- return err;

+ return 0;
}

/**
@@ -407,8 +435,7 @@ out:
* This function provides a generic read implementation for the global state
* "data" structure debugfs filesystem entries. It would be nice to use
* simple_attr_read directly, but we need to make sure that the data.lock
- * spinlock is held during the actual read (even though we likely won't ever
- * actually race here as the updater runs under a stop_machine context).
+ * is held during the actual read.
*/
static ssize_t simple_data_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos, const u64 *entry)
@@ -443,8 +470,7 @@ static ssize_t simple_data_read(struct file *filp, char __user *ubuf,
* This function provides a generic write implementation for the global state
* "data" structure debugfs filesystem entries. It would be nice to use
* simple_attr_write directly, but we need to make sure that the data.lock
- * spinlock is held during the actual write (even though we likely won't ever
- * actually race here as the updater runs under a stop_machine context).
+ * is held during the actual write.
*/
static ssize_t simple_data_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos, u64 *entry)
@@ -738,10 +764,11 @@ static ssize_t debug_sample_fread(struct file *filp, char __user *ubuf,
}
}

- len = snprintf(buf, sizeof(buf), "%010lu.%010lu\t%llu\n",
- sample->timestamp.tv_sec,
- sample->timestamp.tv_nsec,
- sample->duration);
+ len = snprintf(buf, sizeof(buf), "%010lu.%010lu\t%llu\t%llu\n",
+ sample->timestamp.tv_sec,
+ sample->timestamp.tv_nsec,
+ sample->duration,
+ sample->outer_duration);


/* handling partial reads is more trouble than it's worth */
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f70a65b..42f79fb 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -271,6 +271,7 @@ struct irq_affinity_notify {
unsigned int irq;
struct kref kref;
struct work_struct work;
+ struct list_head list;
void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
void (*release)(struct kref *ref);
};
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
index 31f9d75..becd7a6 100644
--- a/include/linux/list_bl.h
+++ b/include/linux/list_bl.h
@@ -2,6 +2,7 @@
#define _LINUX_LIST_BL_H

#include <linux/list.h>
+#include <linux/spinlock.h>
#include <linux/bit_spinlock.h>

/*
@@ -32,13 +33,22 @@

struct hlist_bl_head {
struct hlist_bl_node *first;
+#ifdef CONFIG_PREEMPT_RT_BASE
+ raw_spinlock_t lock;
+#endif
};

struct hlist_bl_node {
struct hlist_bl_node *next, **pprev;
};
-#define INIT_HLIST_BL_HEAD(ptr) \
- ((ptr)->first = NULL)
+
+static inline void INIT_HLIST_BL_HEAD(struct hlist_bl_head *h)
+{
+ h->first = NULL;
+#ifdef CONFIG_PREEMPT_RT_BASE
+ raw_spin_lock_init(&h->lock);
+#endif
+}

static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h)
{
@@ -117,12 +127,26 @@ static inline void hlist_bl_del_init(struct hlist_bl_node *n)

static inline void hlist_bl_lock(struct hlist_bl_head *b)
{
+#ifndef CONFIG_PREEMPT_RT_BASE
bit_spin_lock(0, (unsigned long *)b);
+#else
+ raw_spin_lock(&b->lock);
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+ __set_bit(0, (unsigned long *)b);
+#endif
+#endif
}

static inline void hlist_bl_unlock(struct hlist_bl_head *b)
{
+#ifndef CONFIG_PREEMPT_RT_BASE
__bit_spin_unlock(0, (unsigned long *)b);
+#else
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+ __clear_bit(0, (unsigned long *)b);
+#endif
+ raw_spin_unlock(&b->lock);
+#endif
}

/**
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 5ef0c31..063c2bb 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -78,6 +78,7 @@ struct hotplug_pcp {
int refcount;
int grab_lock;
struct completion synced;
+ struct completion unplug_wait;
#ifdef CONFIG_PREEMPT_RT_FULL
spinlock_t lock;
#else
@@ -175,6 +176,7 @@ static int sync_unplug_thread(void *data)
{
struct hotplug_pcp *hp = data;

+ wait_for_completion(&hp->unplug_wait);
preempt_disable();
hp->unplug = current;
wait_for_pinned_cpus(hp);
@@ -240,6 +242,14 @@ static void __cpu_unplug_sync(struct hotplug_pcp *hp)
wait_for_completion(&hp->synced);
}

+static void __cpu_unplug_wait(unsigned int cpu)
+{
+ struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
+
+ complete(&hp->unplug_wait);
+ wait_for_completion(&hp->synced);
+}
+
/*
* Start the sync_unplug_thread on the target cpu and wait for it to
* complete.
@@ -263,6 +273,7 @@ static int cpu_unplug_begin(unsigned int cpu)
tell_sched_cpu_down_begin(cpu);

init_completion(&hp->synced);
+ init_completion(&hp->unplug_wait);

hp->sync_tsk = kthread_create(sync_unplug_thread, hp, "sync_unplug/%d", cpu);
if (IS_ERR(hp->sync_tsk)) {
@@ -278,8 +289,7 @@ static int cpu_unplug_begin(unsigned int cpu)
* wait for tasks that are going to enter these sections and
* we must not have them block.
*/
- __cpu_unplug_sync(hp);
-
+ wake_up_process(hp->sync_tsk);
return 0;
}

@@ -508,6 +518,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
.hcpu = hcpu,
};
cpumask_var_t cpumask;
+ cpumask_var_t cpumask_org;

if (num_online_cpus() == 1)
return -EBUSY;
@@ -518,6 +529,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
/* Move the downtaker off the unplug cpu */
if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
return -ENOMEM;
+ if (!alloc_cpumask_var(&cpumask_org, GFP_KERNEL)) {
+ free_cpumask_var(cpumask);
+ return -ENOMEM;
+ }
+
+ cpumask_copy(cpumask_org, tsk_cpus_allowed(current));
cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu));
set_cpus_allowed_ptr(current, cpumask);
free_cpumask_var(cpumask);
@@ -526,7 +543,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
if (mycpu == cpu) {
printk(KERN_ERR "Yuck! Still on unplug CPU\n!");
migrate_enable();
- return -EBUSY;
+ err = -EBUSY;
+ goto restore_cpus;
}

cpu_hotplug_begin();
@@ -545,6 +563,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
goto out_release;
}

+ __cpu_unplug_wait(cpu);
+
/* Notifiers are done. Don't let any more tasks pin this CPU. */
cpu_unplug_sync(cpu);

@@ -582,6 +602,9 @@ out_cancel:
cpu_hotplug_done();
if (!err)
cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
+restore_cpus:
+ set_cpus_allowed_ptr(current, cpumask_org);
+ free_cpumask_var(cpumask_org);
return err;
}

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index b3c753e..88a4ff5 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -141,6 +141,62 @@ static inline void
irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
#endif

+#ifdef CONFIG_PREEMPT_RT_FULL
+static void _irq_affinity_notify(struct irq_affinity_notify *notify);
+static struct task_struct *set_affinity_helper;
+static LIST_HEAD(affinity_list);
+static DEFINE_RAW_SPINLOCK(affinity_list_lock);
+
+static int set_affinity_thread(void *unused)
+{
+ while (1) {
+ struct irq_affinity_notify *notify;
+ int empty;
+
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ raw_spin_lock_irq(&affinity_list_lock);
+ empty = list_empty(&affinity_list);
+ raw_spin_unlock_irq(&affinity_list_lock);
+
+ if (empty)
+ schedule();
+ if (kthread_should_stop())
+ break;
+ set_current_state(TASK_RUNNING);
+try_next:
+ notify = NULL;
+
+ raw_spin_lock_irq(&affinity_list_lock);
+ if (!list_empty(&affinity_list)) {
+ notify = list_first_entry(&affinity_list,
+ struct irq_affinity_notify, list);
+ list_del_init(&notify->list);
+ }
+ raw_spin_unlock_irq(&affinity_list_lock);
+
+ if (!notify)
+ continue;
+ _irq_affinity_notify(notify);
+ goto try_next;
+ }
+ return 0;
+}
+
+static void init_helper_thread(void)
+{
+ if (set_affinity_helper)
+ return;
+ set_affinity_helper = kthread_run(set_affinity_thread, NULL,
+ "affinity-cb");
+ WARN_ON(IS_ERR(set_affinity_helper));
+}
+#else
+
+static inline void init_helper_thread(void) { }
+
+#endif
+
int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
{
struct irq_chip *chip = irq_data_get_irq_chip(data);
@@ -166,7 +222,17 @@ int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)

if (desc->affinity_notify) {
kref_get(&desc->affinity_notify->kref);
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+ raw_spin_lock(&affinity_list_lock);
+ if (list_empty(&desc->affinity_notify->list))
+ list_add_tail(&affinity_list,
+ &desc->affinity_notify->list);
+ raw_spin_unlock(&affinity_list_lock);
+ wake_up_process(set_affinity_helper);
+#else
schedule_work(&desc->affinity_notify->work);
+#endif
}
irqd_set(data, IRQD_AFFINITY_SET);

@@ -207,10 +273,8 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
}
EXPORT_SYMBOL_GPL(irq_set_affinity_hint);

-static void irq_affinity_notify(struct work_struct *work)
+static void _irq_affinity_notify(struct irq_affinity_notify *notify)
{
- struct irq_affinity_notify *notify =
- container_of(work, struct irq_affinity_notify, work);
struct irq_desc *desc = irq_to_desc(notify->irq);
cpumask_var_t cpumask;
unsigned long flags;
@@ -232,6 +296,13 @@ out:
kref_put(&notify->kref, notify->release);
}

+static void irq_affinity_notify(struct work_struct *work)
+{
+ struct irq_affinity_notify *notify =
+ container_of(work, struct irq_affinity_notify, work);
+ _irq_affinity_notify(notify);
+}
+
/**
* irq_set_affinity_notifier - control notification of IRQ affinity changes
* @irq: Interrupt for which to enable/disable notification
@@ -261,6 +332,8 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
notify->irq = irq;
kref_init(&notify->kref);
INIT_WORK(&notify->work, irq_affinity_notify);
+ INIT_LIST_HEAD(&notify->list);
+ init_helper_thread();
}

raw_spin_lock_irqsave(&desc->lock, flags);
@@ -783,9 +856,6 @@ static irqreturn_t irq_thread_fn(struct irq_desc *desc,
*/
static int irq_thread(void *data)
{
- static const struct sched_param param = {
- .sched_priority = MAX_USER_RT_PRIO/2,
- };
struct irqaction *action = data;
struct irq_desc *desc = irq_to_desc(action->irq);
irqreturn_t (*handler_fn)(struct irq_desc *desc,
@@ -798,7 +868,6 @@ static int irq_thread(void *data)
else
handler_fn = irq_thread_fn;

- sched_setscheduler(current, SCHED_FIFO, &param);
current->irqaction = action;

while (!irq_wait_for_interrupt(action)) {
@@ -961,6 +1030,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
*/
if (new->thread_fn && !nested) {
struct task_struct *t;
+ static const struct sched_param param = {
+ .sched_priority = MAX_USER_RT_PRIO/2,
+ };

t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
new->name);
@@ -968,6 +1040,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
ret = PTR_ERR(t);
goto out_mput;
}
+
+ sched_setscheduler(t, SCHED_FIFO, &param);
+
/*
* We keep the reference to the task struct even if
* the thread dies to avoid that the interrupt code
diff --git a/kernel/sched.c b/kernel/sched.c
index dbd9a43..4c37a42 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4803,8 +4803,10 @@ static inline void sched_submit_work(struct task_struct *tsk)
/*
* If a worker went to sleep, notify and ask workqueue whether
* it wants to wake up a task to maintain concurrency.
+ * Only call wake up if prev isn't blocked on a sleeping
+ * spin lock.
*/
- if (tsk->flags & PF_WQ_WORKER)
+ if (tsk->flags & PF_WQ_WORKER && !tsk->saved_state)
wq_worker_sleeping(tsk);

/*
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 4b63943..7d5241e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -10,6 +10,7 @@
#include <linux/workqueue.h>
#include <linux/hrtimer.h>
#include <linux/jiffies.h>
+#include <linux/kthread.h>
#include <linux/math64.h>
#include <linux/timex.h>
#include <linux/time.h>
@@ -490,11 +491,52 @@ static void sync_cmos_clock(struct work_struct *work)
schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
}

+#ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * RT can not call schedule_delayed_work from real interrupt context.
+ * Need to make a thread to do the real work.
+ */
+static struct task_struct *cmos_delay_thread;
+static bool do_cmos_delay;
+
+static int run_cmos_delay(void *ignore)
+{
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (do_cmos_delay) {
+ do_cmos_delay = false;
+ schedule_delayed_work(&sync_cmos_work, 0);
+ }
+ schedule();
+ }
+ __set_current_state(TASK_RUNNING);
+ return 0;
+}
+
+static void notify_cmos_timer(void)
+{
+ if (!no_sync_cmos_clock) {
+ do_cmos_delay = true;
+ /* Make visible before waking up process */
+ smp_wmb();
+ wake_up_process(cmos_delay_thread);
+ }
+}
+
+static __init int create_cmos_delay_thread(void)
+{
+ cmos_delay_thread = kthread_run(run_cmos_delay, NULL, "kcmosdelayd");
+ BUG_ON(!cmos_delay_thread);
+ return 0;
+}
+early_initcall(create_cmos_delay_thread);
+#else
static void notify_cmos_timer(void)
{
if (!no_sync_cmos_clock)
schedule_delayed_work(&sync_cmos_work, 0);
}
+#endif /* CONFIG_PREEMPT_RT_FULL */

#else
static inline void notify_cmos_timer(void) { }
diff --git a/kernel/timer.c b/kernel/timer.c
index 2f114d1..7fa30e0 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -76,7 +76,9 @@ struct tvec_root {
struct tvec_base {
spinlock_t lock;
struct timer_list *running_timer;
+#ifdef CONFIG_PREEMPT_RT_FULL
wait_queue_head_t wait_for_running_timer;
+#endif
unsigned long timer_jiffies;
unsigned long next_timer;
struct tvec_root tv1;
@@ -930,7 +932,7 @@ static void wait_for_running_timer(struct timer_list *timer)
base->running_timer != timer);
}

-# define wakeup_timer_waiters(b) wake_up(&(b)->wait_for_tunning_timer)
+# define wakeup_timer_waiters(b) wake_up(&(b)->wait_for_running_timer)
#else
static inline void wait_for_running_timer(struct timer_list *timer)
{
@@ -1183,7 +1185,7 @@ static inline void __run_timers(struct tvec_base *base)
spin_lock_irq(&base->lock);
}
}
- wake_up(&base->wait_for_running_timer);
+ wakeup_timer_waiters(base);
spin_unlock_irq(&base->lock);
}

@@ -1706,7 +1708,9 @@ static int __cpuinit init_timers_cpu(int cpu)
base = &boot_tvec_bases;
}
spin_lock_init(&base->lock);
+#ifdef CONFIG_PREEMPT_RT_FULL
init_waitqueue_head(&base->wait_for_running_timer);
+#endif
tvec_base_done[cpu] = 1;
} else {
base = per_cpu(tvec_bases, cpu);
diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c
index 3947835..1bbb1b2 100644
--- a/kernel/trace/trace_clock.c
+++ b/kernel/trace/trace_clock.c
@@ -44,6 +44,7 @@ u64 notrace trace_clock_local(void)

return clock;
}
+EXPORT_SYMBOL_GPL(trace_clock_local);

/*
* trace_clock(): 'between' trace clock. Not completely serialized,
diff --git a/localversion-rt b/localversion-rt
index f36b5d4..f38a3cc 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt70
+-rt71
--
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