[ANNOUNCE] 3.8.13-rt16

From: Steven Rostedt
Date: Wed Sep 11 2013 - 21:07:33 EST


Dear RT Folks,

I'm pleased to announce the 3.8.13-rt16 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: v3.8-rt
Head SHA1: 983a26769301b0e19ce787baf37a58ee73cd34f7


Or to build 3.8.13-rt16 directly, the following patches should be applied:

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.8.tar.xz

http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.8.13.xz

http://www.kernel.org/pub/linux/kernel/projects/rt/3.8/patch-3.8.13-rt16.patch.xz



You can also build from 3.8.13-rt15 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.8/incr/patch-3.8.13-rt15-rt16.patch.xz



Enjoy,

-- Steve


Changes from v3.8.13-rt15:

---

John Kacur (1):
hpsa: fix warning with smp_processor_id() in preemptible section

Sebastian Andrzej Siewior (2):
powerpc: 52xx: provide a default in mpc52xx_irqhost_map()
genirq: do not invoke the affinity callback via a workqueue

Steven Rostedt (4):
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 3.8.13-rt16

Thomas Gleixner (1):
sched: Distangle worker accounting from rqlock

----
arch/powerpc/platforms/52xx/mpc52xx_pic.c | 3 +-
drivers/misc/hwlat_detector.c | 117 ++++++++++++++++++-----------
drivers/scsi/hpsa.c | 2 +-
include/linux/interrupt.h | 1 +
kernel/irq/manage.c | 79 ++++++++++++++++++-
kernel/sched/core.c | 70 ++++-------------
kernel/time/ntp.c | 40 ++++++++++
kernel/trace/trace_clock.c | 1 +
kernel/workqueue.c | 63 +++++++---------
kernel/workqueue_sched.h | 5 +-
localversion-rt | 2 +-
11 files changed, 240 insertions(+), 143 deletions(-)
---------------------------
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_pic.c b/arch/powerpc/platforms/52xx/mpc52xx_pic.c
index b89ef65..b69221b 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_pic.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_pic.c
@@ -373,8 +373,9 @@ static int mpc52xx_irqhost_map(struct irq_domain *h, unsigned int virq,
case MPC52xx_IRQ_L1_PERP: irqchip = &mpc52xx_periph_irqchip; break;
case MPC52xx_IRQ_L1_SDMA: irqchip = &mpc52xx_sdma_irqchip; break;
case MPC52xx_IRQ_L1_CRIT:
+ default:
pr_warn("%s: Critical IRQ #%d is unsupported! Nopping it.\n",
- __func__, l2irq);
+ __func__, l1irq);
irq_set_chip(virq, &no_irq_chip);
return 0;
}
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/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 4f33806..80a44b1 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -583,7 +583,7 @@ static void set_performant_mode(struct ctlr_info *h, struct CommandList *c)
c->busaddr |= 1 | (h->blockFetchTable[c->Header.SGList] << 1);
if (likely(h->msix_vector))
c->Header.ReplyQueue =
- smp_processor_id() % h->nreply_queues;
+ raw_smp_processor_id() % h->nreply_queues;
}
}

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 11bdb1e..838d4bd 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -263,6 +263,7 @@ 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/kernel/irq/manage.c b/kernel/irq/manage.c
index 81a28dd..cf5b5f7 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -163,6 +163,62 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
return ret;
}

+#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);
@@ -181,7 +237,17 @@ 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);

@@ -222,10 +288,8 @@ 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;
@@ -247,6 +311,13 @@ 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
@@ -276,6 +347,8 @@ 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);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 505e08f..d7c1471 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1321,10 +1321,6 @@ static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
{
activate_task(rq, p, en_flags);
p->on_rq = 1;
-
- /* if a worker is waking up, notify workqueue */
- if (p->flags & PF_WQ_WORKER)
- wq_worker_waking_up(p, cpu_of(rq));
}

/*
@@ -1551,42 +1547,6 @@ out:
}

/**
- * try_to_wake_up_local - try to wake up a local task with rq lock held
- * @p: the thread to be awakened
- *
- * Put @p on the run-queue if it's not already there. The caller must
- * ensure that this_rq() is locked, @p is bound to this_rq() and not
- * the current task.
- */
-static void try_to_wake_up_local(struct task_struct *p)
-{
- struct rq *rq = task_rq(p);
-
- if (WARN_ON_ONCE(rq != this_rq()) ||
- WARN_ON_ONCE(p == current))
- return;
-
- lockdep_assert_held(&rq->lock);
-
- if (!raw_spin_trylock(&p->pi_lock)) {
- raw_spin_unlock(&rq->lock);
- raw_spin_lock(&p->pi_lock);
- raw_spin_lock(&rq->lock);
- }
-
- if (!(p->state & TASK_NORMAL))
- goto out;
-
- if (!p->on_rq)
- ttwu_activate(rq, p, ENQUEUE_WAKEUP);
-
- ttwu_do_wakeup(rq, p, 0);
- ttwu_stat(p, smp_processor_id(), 0);
-out:
- raw_spin_unlock(&p->pi_lock);
-}
-
-/**
* wake_up_process - Wake up a specific process
* @p: The process to be woken up.
*
@@ -3139,21 +3099,6 @@ need_resched:
} else {
deactivate_task(rq, prev, DEQUEUE_SLEEP);
prev->on_rq = 0;
-
- /*
- * 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 (prev->flags & PF_WQ_WORKER && !prev->saved_state) {
- struct task_struct *to_wakeup;
-
- to_wakeup = wq_worker_sleeping(prev, cpu);
- if (to_wakeup)
- try_to_wake_up_local(to_wakeup);
- }
}
switch_count = &prev->nvcsw;
}
@@ -3197,6 +3142,14 @@ static inline void sched_submit_work(struct task_struct *tsk)
{
if (!tsk->state || tsk_is_pi_blocked(tsk))
return;
+
+ /*
+ * If a worker went to sleep, notify and ask workqueue whether
+ * it wants to wake up a task to maintain concurrency.
+ */
+ if (tsk->flags & PF_WQ_WORKER)
+ wq_worker_sleeping(tsk);
+
/*
* If we are going to sleep and we have plugged IO queued,
* make sure to submit it to avoid deadlocks.
@@ -3205,12 +3158,19 @@ static inline void sched_submit_work(struct task_struct *tsk)
blk_schedule_flush_plug(tsk);
}

+static inline void sched_update_worker(struct task_struct *tsk)
+{
+ if (tsk->flags & PF_WQ_WORKER)
+ wq_worker_running(tsk);
+}
+
asmlinkage void __sched schedule(void)
{
struct task_struct *tsk = current;

sched_submit_work(tsk);
__schedule();
+ sched_update_worker(tsk);
}
EXPORT_SYMBOL(schedule);

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index bb1edfa..3e93516 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>
@@ -529,10 +530,49 @@ 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)
+{
+ 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)
{
schedule_delayed_work(&sync_cmos_work, 0);
}
+#endif /* CONFIG_PREEMPT_RT_FULL */

#else
static inline void notify_cmos_timer(void) { }
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/kernel/workqueue.c b/kernel/workqueue.c
index 99855b3..788b017 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -149,6 +149,7 @@ struct worker {
unsigned long last_active; /* L: last active timestamp */
unsigned int flags; /* X: flags */
int id; /* I: worker id */
+ int sleeping; /* None */

/* for rebinding worker to CPU */
struct work_struct rebind_work; /* L: for busy worker */
@@ -730,54 +731,45 @@ static void wake_up_worker(struct worker_pool *pool)
}

/**
- * wq_worker_waking_up - a worker is waking up
- * @task: task waking up
- * @cpu: CPU @task is waking up to
+ * wq_worker_running - a worker is running again
+ * @task: task returning from sleep
*
- * This function is called during try_to_wake_up() when a worker is
- * being awoken.
- *
- * CONTEXT:
- * spin_lock_irq(rq->lock)
+ * This function is called when a worker returns from schedule()
*/
-void wq_worker_waking_up(struct task_struct *task, unsigned int cpu)
+void wq_worker_running(struct task_struct *task)
{
struct worker *worker = kthread_data(task);

- if (!(worker->flags & WORKER_NOT_RUNNING)) {
- WARN_ON_ONCE(worker->pool->gcwq->cpu != cpu);
+ if (!worker->sleeping)
+ return;
+ if (!(worker->flags & WORKER_NOT_RUNNING))
atomic_inc(get_pool_nr_running(worker->pool));
- }
+ worker->sleeping = 0;
}

/**
* wq_worker_sleeping - a worker is going to sleep
* @task: task going to sleep
- * @cpu: CPU in question, must be the current CPU number
- *
- * This function is called during schedule() when a busy worker is
- * going to sleep. Worker on the same cpu can be woken up by
- * returning pointer to its task.
- *
- * CONTEXT:
- * spin_lock_irq(rq->lock)
- *
- * RETURNS:
- * Worker task on @cpu to wake up, %NULL if none.
+ * This function is called from schedule() when a busy worker is
+ * going to sleep.
*/
-struct task_struct *wq_worker_sleeping(struct task_struct *task,
- unsigned int cpu)
+void wq_worker_sleeping(struct task_struct *task)
{
- struct worker *worker = kthread_data(task), *to_wakeup = NULL;
- struct worker_pool *pool = worker->pool;
- atomic_t *nr_running = get_pool_nr_running(pool);
+ struct worker *next, *worker = kthread_data(task);
+ struct worker_pool *pool;
+ atomic_t *nr_running;

if (worker->flags & WORKER_NOT_RUNNING)
- return NULL;
+ return;
+
+ if (WARN_ON_ONCE(worker->sleeping))
+ return;

- /* this can only happen on the local cpu */
- BUG_ON(cpu != raw_smp_processor_id());
+ pool = worker->pool;
+ nr_running = get_pool_nr_running(pool);

+ worker->sleeping = 1;
+ spin_lock_irq(&pool->gcwq->lock);
/*
* The counterpart of the following dec_and_test, implied mb,
* worklist not empty test sequence is in insert_work().
@@ -789,9 +781,12 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task,
* manipulating idle_list, so dereferencing idle_list without gcwq
* lock is safe.
*/
- if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist))
- to_wakeup = first_worker(pool);
- return to_wakeup ? to_wakeup->task : NULL;
+ if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) {
+ next = first_worker(pool);
+ if (next)
+ wake_up_process(next->task);
+ }
+ spin_unlock_irq(&pool->gcwq->lock);
}

/**
diff --git a/kernel/workqueue_sched.h b/kernel/workqueue_sched.h
index 2d10fc9..3bf73e2 100644
--- a/kernel/workqueue_sched.h
+++ b/kernel/workqueue_sched.h
@@ -4,6 +4,5 @@
* Scheduler hooks for concurrency managed workqueue. Only to be
* included from sched.c and workqueue.c.
*/
-void wq_worker_waking_up(struct task_struct *task, unsigned int cpu);
-struct task_struct *wq_worker_sleeping(struct task_struct *task,
- unsigned int cpu);
+void wq_worker_running(struct task_struct *task);
+void wq_worker_sleeping(struct task_struct *task);
diff --git a/localversion-rt b/localversion-rt
index 18777ec..1199eba 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt15
+-rt16
--
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