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Date: Tue, 18 Jun 2013 19:36:52 +0400
From: Kirill Tkhai <tkhai@...dex.ru>
To: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 1/2] sched: Add schedule_(raw_)spin_unlock and schedule_(raw_)spin_unlock_irq
Helpers for replacement repeating patterns:
1)spin_unlock(lock);
schedule();
2)spin_unlock_irq(lock);
schedule();
(The same for raw_spinlock_t)
This allows to prevent excess preempt_schedule(), which can happen on preemptible kernel.
Signed-off-by: Kirill Tkhai <tkhai@...dex.ru>
CC: Steven Rostedt <rostedt@...dmis.org>
CC: Ingo Molnar <mingo@...hat.com>
CC: Peter Zijlstra <peterz@...radead.org>
---
include/linux/sched.h | 37 +++++++++++++++++++++++++++++++++++++
include/linux/spinlock_api_smp.h | 21 +++++++++++++++++++++
include/linux/spinlock_api_up.h | 8 ++++++++
kernel/spinlock.c | 13 +++++++++++++
4 files changed, 79 insertions(+), 0 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8b10339..2020071 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -310,6 +310,43 @@ extern signed long schedule_timeout_uninterruptible(signed long timeout);
asmlinkage void schedule(void);
extern void schedule_preempt_disabled(void);
+/*
+ * schedule_raw_spin_unlock() -- should be used instead of pattern:
+ *
+ * raw_spin_unlock(lock);
+ * schedule();
+ *
+ * It's the same, but prevents preempt_schedule() call during the unlocking.
+ */
+static inline void schedule_raw_spin_unlock(raw_spinlock_t *lock)
+{
+ _raw_spin_unlock_no_resched(lock);
+ schedule();
+}
+
+/*
+ * schedule_raw_spin_unlock_irq() -- should be used instead of pattern:
+ *
+ * raw_spin_unlock_irq(lock);
+ * schedule();
+ *
+ * It's the same, but prevents preempt_schedule() call during the unlocking.
+ */
+static inline void schedule_raw_spin_unlock_irq(raw_spinlock_t *lock)
+{
+ _raw_spin_unlock_irq_no_resched(lock);
+ schedule();
+}
+
+static inline void schedule_spin_unlock(spinlock_t *lock)
+{
+ schedule_raw_spin_unlock(&lock->rlock);
+}
+static inline void schedule_spin_unlock_irq(spinlock_t *lock)
+{
+ schedule_raw_spin_unlock_irq(&lock->rlock);
+}
+
struct nsproxy;
struct user_namespace;
diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h
index 51df117..42dbdfe 100644
--- a/include/linux/spinlock_api_smp.h
+++ b/include/linux/spinlock_api_smp.h
@@ -42,6 +42,10 @@ void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock) __releases(lock);
void __lockfunc
_raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
__releases(lock);
+void __lockfunc
+_raw_spin_unlock_no_resched(raw_spinlock_t *lock) __releases(lock);
+void __lockfunc
+_raw_spin_unlock_irq_no_resched(raw_spinlock_t *lock) __releases(lock);
#ifdef CONFIG_INLINE_SPIN_LOCK
#define _raw_spin_lock(lock) __raw_spin_lock(lock)
@@ -69,6 +73,7 @@ _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
#ifndef CONFIG_UNINLINE_SPIN_UNLOCK
#define _raw_spin_unlock(lock) __raw_spin_unlock(lock)
+#define _raw_spin_unlock_no_resched(lock) __raw_spin_unlock_no_resched(lock)
#endif
#ifdef CONFIG_INLINE_SPIN_UNLOCK_BH
@@ -77,6 +82,7 @@ _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
#ifdef CONFIG_INLINE_SPIN_UNLOCK_IRQ
#define _raw_spin_unlock_irq(lock) __raw_spin_unlock_irq(lock)
+#define _raw_spin_unlock_irq_no_resched(lock) __raw_spin_unlock_irq_no_resched(lock)
#endif
#ifdef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
@@ -153,6 +159,13 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock)
preempt_enable();
}
+static inline void __raw_spin_unlock_no_resched(raw_spinlock_t *lock)
+{
+ spin_release(&lock->dep_map, 1, _RET_IP_);
+ do_raw_spin_unlock(lock);
+ preempt_enable_no_resched();
+}
+
static inline void __raw_spin_unlock_irqrestore(raw_spinlock_t *lock,
unsigned long flags)
{
@@ -170,6 +183,14 @@ static inline void __raw_spin_unlock_irq(raw_spinlock_t *lock)
preempt_enable();
}
+static inline void __raw_spin_unlock_irq_no_resched(raw_spinlock_t *lock)
+{
+ spin_release(&lock->dep_map, 1, _RET_IP_);
+ do_raw_spin_unlock(lock);
+ local_irq_enable();
+ preempt_enable_no_resched();
+}
+
static inline void __raw_spin_unlock_bh(raw_spinlock_t *lock)
{
spin_release(&lock->dep_map, 1, _RET_IP_);
diff --git a/include/linux/spinlock_api_up.h b/include/linux/spinlock_api_up.h
index af1f472..82280da 100644
--- a/include/linux/spinlock_api_up.h
+++ b/include/linux/spinlock_api_up.h
@@ -39,6 +39,9 @@
#define __UNLOCK(lock) \
do { preempt_enable(); __release(lock); (void)(lock); } while (0)
+#define __UNLOCK_NO_RESCHED(lock) \
+ do { preempt_enable_no_resched(); __release(lock); (void)(lock); } while (0)
+
#define __UNLOCK_BH(lock) \
do { preempt_enable_no_resched(); local_bh_enable(); \
__release(lock); (void)(lock); } while (0)
@@ -46,6 +49,9 @@
#define __UNLOCK_IRQ(lock) \
do { local_irq_enable(); __UNLOCK(lock); } while (0)
+#define __UNLOCK_IRQ_NO_RESCHED(lock) \
+ do { local_irq_enable(); __UNLOCK_NO_RESCHED(lock); } while (0)
+
#define __UNLOCK_IRQRESTORE(lock, flags) \
do { local_irq_restore(flags); __UNLOCK(lock); } while (0)
@@ -67,12 +73,14 @@
#define _raw_write_trylock(lock) ({ __LOCK(lock); 1; })
#define _raw_spin_trylock_bh(lock) ({ __LOCK_BH(lock); 1; })
#define _raw_spin_unlock(lock) __UNLOCK(lock)
+#define _raw_spin_unlock_no_resched(lock) __UNLOCK_NO_RESCHED(lock)
#define _raw_read_unlock(lock) __UNLOCK(lock)
#define _raw_write_unlock(lock) __UNLOCK(lock)
#define _raw_spin_unlock_bh(lock) __UNLOCK_BH(lock)
#define _raw_write_unlock_bh(lock) __UNLOCK_BH(lock)
#define _raw_read_unlock_bh(lock) __UNLOCK_BH(lock)
#define _raw_spin_unlock_irq(lock) __UNLOCK_IRQ(lock)
+#define _raw_spin_unlock_irq_no_resched(lock) __UNLOCK_IRQ_NO_RESCHED(lock)
#define _raw_read_unlock_irq(lock) __UNLOCK_IRQ(lock)
#define _raw_write_unlock_irq(lock) __UNLOCK_IRQ(lock)
#define _raw_spin_unlock_irqrestore(lock, flags) \
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index 5cdd806..218058f 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -169,6 +169,13 @@ void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
__raw_spin_unlock(lock);
}
EXPORT_SYMBOL(_raw_spin_unlock);
+
+void __lockfunc _raw_spin_unlock_no_resched(raw_spinlock_t *lock)
+{
+ __raw_spin_unlock_no_resched(lock);
+}
+EXPORT_SYMBOL(_raw_spin_unlock_no_resched);
+
#endif
#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
@@ -185,6 +192,12 @@ void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
__raw_spin_unlock_irq(lock);
}
EXPORT_SYMBOL(_raw_spin_unlock_irq);
+
+void __lockfunc _raw_spin_unlock_irq_no_resched(raw_spinlock_t *lock)
+{
+ __raw_spin_unlock_irq_no_resched(lock);
+}
+EXPORT_SYMBOL(_raw_spin_unlock_irq_no_resched);
#endif
#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
--
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