Dear RT Folks,
I'm pleased to announce the 3.6.9-rt21 release. 3.6.7-rt18, 3.6.8-rt19
and 3.6.9-rt20 are not announced updates to the respective 3.6.y
stable releases without any RT changes
Changes since 3.6.9-rt20:
* Fix the PREEMPT_LAZY implementation on ARM
* Fix the RCUTINY issues
* Fix a long standing scheduler bug (See commit log of
sched-enqueue-to-head.patch)
Known issues:
* There is still a possibility to get false positives from the NOHZ
idle softirq pending detector. It's rather complex to fix and I
have postponed it for a separate release. The warnings are
harmless and can be ignored for now.
The delta patch against 3.6.9-rt20 is appended below and can be found
here:
http://www.kernel.org/pub/linux/kernel/projects/rt/3.6/incr/patch-3.6.9-rt20-rt21.patch.xz
The RT patch against 3.6.9 can be found here:
http://www.kernel.org/pub/linux/kernel/projects/rt/3.6/patch-3.6.9-rt21.patch.xz
The split quilt queue is available at:
http://www.kernel.org/pub/linux/kernel/projects/rt/3.6/patches-3.6.9-rt21.tar.xz
Enjoy,
tglx
------------->
Index: linux-stable/arch/arm/kernel/entry-armv.S
===================================================================
--- linux-stable.orig/arch/arm/kernel/entry-armv.S
+++ linux-stable/arch/arm/kernel/entry-armv.S
@@ -216,17 +216,18 @@ __irq_svc:
#ifdef CONFIG_PREEMPT
get_thread_info tsk
ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
- ldr r0, [tsk, #TI_FLAGS] @ get flags
teq r8, #0 @ if preempt count != 0
- movne r0, #0 @ force flags to 0
- tst r0, #_TIF_NEED_RESCHED
- blne svc_preempt
- ldr r8, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count
+ bne 1f @ return from exeption
ldr r0, [tsk, #TI_FLAGS] @ get flags
+ tst r0, #_TIF_NEED_RESCHED @ if NEED_RESCHED is set
+ blne svc_preempt @ preempt!
+
+ ldr r8, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count
teq r8, #0 @ if preempt lazy count != 0
movne r0, #0 @ force flags to 0
tst r0, #_TIF_NEED_RESCHED_LAZY
blne svc_preempt
+1:
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
Index: linux-stable/kernel/Makefile
===================================================================
--- linux-stable.orig/kernel/Makefile
+++ linux-stable/kernel/Makefile
@@ -10,7 +10,7 @@ obj-y = fork.o exec_domain.o panic.o
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o \
hrtimer.o nsproxy.o srcu.o semaphore.o \
notifier.o ksysfs.o cred.o \
- async.o range.o groups.o lglock.o
+ async.o range.o groups.o lglock.o wait-simple.o
ifdef CONFIG_FUNCTION_TRACER
# Do not trace debug files and internal ftrace files
Index: linux-stable/kernel/rcutiny_plugin.h
===================================================================
--- linux-stable.orig/kernel/rcutiny_plugin.h
+++ linux-stable/kernel/rcutiny_plugin.h
@@ -26,6 +26,7 @@
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
+#include <linux/wait-simple.h>
/* Global control variables for rcupdate callback mechanism. */
struct rcu_ctrlblk {
@@ -260,7 +261,7 @@ static void show_tiny_preempt_stats(stru
/* Controls for rcu_kthread() kthread. */
static struct task_struct *rcu_kthread_task;
-static DECLARE_WAIT_QUEUE_HEAD(rcu_kthread_wq);
+static DEFINE_SWAIT_HEAD(rcu_kthread_wq);
static unsigned long have_rcu_kthread_work;
/*
@@ -710,7 +711,7 @@ void synchronize_rcu(void)
}
EXPORT_SYMBOL_GPL(synchronize_rcu);
-static DECLARE_WAIT_QUEUE_HEAD(sync_rcu_preempt_exp_wq);
+static DEFINE_SWAIT_HEAD(sync_rcu_preempt_exp_wq);
static unsigned long sync_rcu_preempt_exp_count;
static DEFINE_MUTEX(sync_rcu_preempt_exp_mutex);
@@ -732,7 +733,7 @@ static int rcu_preempted_readers_exp(voi
*/
static void rcu_report_exp_done(void)
{
- wake_up(&sync_rcu_preempt_exp_wq);
+ swait_wake(&sync_rcu_preempt_exp_wq);
}
/*
@@ -784,8 +785,8 @@ void synchronize_rcu_expedited(void)
} else {
rcu_initiate_boost();
local_irq_restore(flags);
- wait_event(sync_rcu_preempt_exp_wq,
- !rcu_preempted_readers_exp());
+ swait_event(sync_rcu_preempt_exp_wq,
+ !rcu_preempted_readers_exp());
}
/* Clean up and exit. */
@@ -855,7 +856,7 @@ static void invoke_rcu_callbacks(void)
{
have_rcu_kthread_work = 1;
if (rcu_kthread_task != NULL)
- wake_up(&rcu_kthread_wq);
+ swait_wake(&rcu_kthread_wq);
}
#ifdef CONFIG_RCU_TRACE
@@ -885,8 +886,8 @@ static int rcu_kthread(void *arg)
unsigned long flags;
for (;;) {
- wait_event_interruptible(rcu_kthread_wq,
- have_rcu_kthread_work != 0);
+ swait_event_interruptible(rcu_kthread_wq,
+ have_rcu_kthread_work != 0);
morework = rcu_boost();
local_irq_save(flags);
work = have_rcu_kthread_work;
Index: linux-stable/kernel/sched/core.c
===================================================================
--- linux-stable.orig/kernel/sched/core.c
+++ linux-stable/kernel/sched/core.c
@@ -4268,6 +4268,8 @@ void rt_mutex_setprio(struct task_struct
trace_sched_pi_setprio(p, prio);
oldprio = p->prio;
+ if (oldprio == prio)
+ goto out_unlock;
prev_class = p->sched_class;
on_rq = p->on_rq;
running = task_current(rq, p);
@@ -4618,6 +4620,13 @@ recheck:
task_rq_unlock(rq, p, &flags);
goto recheck;
}
+
+ p->sched_reset_on_fork = reset_on_fork;
+
+ oldprio = p->prio;
+ if (oldprio == param->sched_priority)
+ goto out;
+
on_rq = p->on_rq;
running = task_current(rq, p);
if (on_rq)
@@ -4625,18 +4634,17 @@ recheck:
if (running)
p->sched_class->put_prev_task(rq, p);
- p->sched_reset_on_fork = reset_on_fork;
-
- oldprio = p->prio;
prev_class = p->sched_class;
__setscheduler(rq, p, policy, param->sched_priority);
if (running)
p->sched_class->set_curr_task(rq);
if (on_rq)
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, oldprio < param->sched_priority ?
+ ENQUEUE_HEAD : 0);
check_class_changed(rq, p, prev_class, oldprio);
+out:
task_rq_unlock(rq, p, &flags);
rt_mutex_adjust_pi(p);
Index: linux-stable/localversion-rt
===================================================================
--- linux-stable.orig/localversion-rt
+++ linux-stable/localversion-rt
@@ -1 +1 @@
--rt20
+-rt21
Index: linux-stable/include/linux/wait-simple.h
===================================================================
--- /dev/null
+++ linux-stable/include/linux/wait-simple.h
@@ -0,0 +1,204 @@
+#ifndef _LINUX_WAIT_SIMPLE_H
+#define _LINUX_WAIT_SIMPLE_H
+
+#include <linux/spinlock.h>
+#include <linux/list.h>
+
+#include <asm/current.h>
+
+struct swaiter {
+ struct task_struct *task;
+ struct list_head node;
+};
+
+#define DEFINE_SWAITER(name) \
+ struct swaiter name = { \
+ .task = current, \
+ .node = LIST_HEAD_INIT((name).node), \
+ }
+
+struct swait_head {
+ raw_spinlock_t lock;
+ struct list_head list;
+};
+
+#define DEFINE_SWAIT_HEAD(name) \
+ struct swait_head name = { \
+ .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
+ .list = LIST_HEAD_INIT((name).list), \
+ }
+
+extern void __init_swait_head(struct swait_head *h, struct lock_class_key
*key);
+
+#define init_swait_head(swh) \
+ do { \
+ static struct lock_class_key __key; \
+ \
+ __init_swait_head((swh), &__key); \
+ } while (0)
+
+/*
+ * Waiter functions
+ */
+static inline bool swaiter_enqueued(struct swaiter *w)
+{
+ return w->task != NULL;
+}
+
+extern void swait_prepare(struct swait_head *head, struct swaiter *w, int
state);
+extern void swait_finish(struct swait_head *head, struct swaiter *w);
+
+/*
+ * Adds w to head->list. Must be called with head->lock locked.
+ */
+static inline void __swait_enqueue(struct swait_head *head, struct swaiter *w)
+{
+ list_add(&w->node, &head->list);
+}
+
+/*
+ * Removes w from head->list. Must be called with head->lock locked.
+ */
+static inline void __swait_dequeue(struct swaiter *w)
+{
+ list_del_init(&w->node);
+}
+
+/*
+ * Check whether a head has waiters enqueued
+ */
+static inline bool swait_head_has_waiters(struct swait_head *h)
+{
+ return !list_empty(&h->list);
+}
+
+/*
+ * Wakeup functions
+ */
+extern int __swait_wake(struct swait_head *head, unsigned int state);
+
+static inline int swait_wake(struct swait_head *head)
+{
+ return swait_head_has_waiters(head) ?
+ __swait_wake(head, TASK_NORMAL) : 0;
+}
+
+static inline int swait_wake_interruptible(struct swait_head *head)
+{
+ return swait_head_has_waiters(head) ?
+ __swait_wake(head, TASK_INTERRUPTIBLE) : 0;
+}
+
+/*
+ * Event API
+ */
+
+#define __swait_event(wq, condition) \
+do { \
+ DEFINE_SWAITER(__wait); \
+ \
+ for (;;) { \
+ swait_prepare(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
+ if (condition) \
+ break; \
+ schedule(); \
+ } \
+ swait_finish(&wq, &__wait); \
+} while (0)
+
+/**
+ * swait_event - sleep until a condition gets true
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ *
+ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
+ * @condition evaluates to true. The @condition is checked each time
+ * the waitqueue @wq is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ */
+#define swait_event(wq, condition) \
+do { \
+ if (condition) \
+ break; \
+ __swait_event(wq, condition); \
+} while (0)
+
+#define __swait_event_interruptible(wq, condition, ret)
\
+do { \
+ DEFINE_SWAITER(__wait); \
+ \
+ for (;;) { \
+ swait_prepare(&wq, &__wait, TASK_INTERRUPTIBLE); \
+ if (condition) \
+ break; \
+ if (signal_pending(current)) { \
+ ret = -ERESTARTSYS; \
+ break; \
+ } \
+ schedule(); \
+ } \
+ swait_finish(&wq, &__wait); \
+} while (0)
+
+/**
+ * swait_event_interruptible - sleep until a condition gets true
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ *
+ * The process is put to sleep (TASK_INTERRUPTIBLE) until the
+ * @condition evaluates to true. The @condition is checked each time
+ * the waitqueue @wq is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ */
+#define swait_event_interruptible(wq, condition) \
+({ \
+ int __ret = 0; \
+ if (!(condition)) \
+ __swait_event_interruptible(wq, condition, __ret); \
+ __ret; \
+})
+
+#define __swait_event_timeout(wq, condition, ret) \
+do { \
+ DEFINE_SWAITER(__wait); \
+ \
+ for (;;) { \
+ swait_prepare(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
+ if (condition) \
+ break; \
+ ret = schedule_timeout(ret); \
+ if (!ret) \
+ break; \
+ } \
+ swait_finish(&wq, &__wait); \
+} while (0)
+
+/**
+ * swait_event_timeout - sleep until a condition gets true or a timeout elapses
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * @timeout: timeout, in jiffies
+ *
+ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
+ * @condition evaluates to true. The @condition is checked each time
+ * the waitqueue @wq is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ *
+ * The function returns 0 if the @timeout elapsed, and the remaining
+ * jiffies if the condition evaluated to true before the timeout elapsed.
+ */
+#define swait_event_timeout(wq, condition, timeout) \
+({ \
+ long __ret = timeout; \
+ if (!(condition)) \
+ __swait_event_timeout(wq, condition, __ret); \
+ __ret; \
+})
+
+#endif
Index: linux-stable/kernel/wait-simple.c
===================================================================
--- /dev/null
+++ linux-stable/kernel/wait-simple.c
@@ -0,0 +1,68 @@
+/*
+ * Simple waitqueues without fancy flags and callbacks
+ *
+ * (C) 2011 Thomas Gleixner <t...@linutronix.de>
+ *
+ * Based on kernel/wait.c
+ *
+ * For licencing details see kernel-base/COPYING
+ */
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/wait-simple.h>
+
+void __init_swait_head(struct swait_head *head, struct lock_class_key *key)
+{
+ raw_spin_lock_init(&head->lock);
+ lockdep_set_class(&head->lock, key);
+ INIT_LIST_HEAD(&head->list);
+}
+EXPORT_SYMBOL_GPL(__init_swait_head);
+
+void swait_prepare(struct swait_head *head, struct swaiter *w, int state)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&head->lock, flags);
+ w->task = current;
+ if (list_empty(&w->node))
+ __swait_enqueue(head, w);
+ set_current_state(state);
+ raw_spin_unlock_irqrestore(&head->lock, flags);
+}
+EXPORT_SYMBOL_GPL(swait_prepare);
+
+void swait_finish(struct swait_head *head, struct swaiter *w)
+{
+ unsigned long flags;
+
+ __set_current_state(TASK_RUNNING);
+ if (w->task) {
+ raw_spin_lock_irqsave(&head->lock, flags);
+ __swait_dequeue(w);
+ raw_spin_unlock_irqrestore(&head->lock, flags);
+ }
+}
+EXPORT_SYMBOL_GPL(swait_finish);
+
+int __swait_wake(struct swait_head *head, unsigned int state)
+{
+ struct swaiter *curr, *next;
+ unsigned long flags;
+ int woken = 0;
+
+ raw_spin_lock_irqsave(&head->lock, flags);
+
+ list_for_each_entry_safe(curr, next, &head->list, node) {
+ if (wake_up_state(curr->task, state)) {
+ __swait_dequeue(curr);
+ curr->task = NULL;
+ woken++;
+ }
+ }
+
+ raw_spin_unlock_irqrestore(&head->lock, flags);
+ return woken;
+}
+EXPORT_SYMBOL_GPL(__swait_wake);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
