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Commit 92cf2118 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

sched/preempt: Merge preempt_mask.h into preempt.h 



preempt_mask.h defines all the preempt_count semantics and related
symbols: preempt, softirq, hardirq, nmi, preempt active, need resched,
etc...

preempt.h defines the accessors and mutators of preempt_count.

But there is a messy dependency game around those two header files:

	* preempt_mask.h includes preempt.h in order to access preempt_count()

	* preempt_mask.h defines all preempt_count semantic and symbols
	  except PREEMPT_NEED_RESCHED that is needed by asm/preempt.h
	  Thus we need to define it from preempt.h, right before including
	  asm/preempt.h, instead of defining it to preempt_mask.h with the
	  other preempt_count symbols. Therefore the preempt_count semantics
	  happen to be spread out.

	* We plan to introduce preempt_active_[enter,exit]() to consolidate
	  preempt_schedule*() code. But we'll need to access both preempt_count
	  mutators (preempt_count_add()) and preempt_count symbols
	  (PREEMPT_ACTIVE, PREEMPT_OFFSET). The usual place to define preempt
	  operations is in preempt.h but then we'll need symbols in
	  preempt_mask.h which already includes preempt.h. So we end up with
	  a ressource circle dependency.

Lets merge preempt_mask.h into preempt.h to solve these dependency issues.
This way we gather semantic symbols and operation definition of
preempt_count in a single file.

This is a dumb copy-paste merge. Further merge re-arrangments are
performed in a subsequent patch to ease review.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431441711-29753-2-git-send-email-fweisbec@gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent a22ae718

arch/m68k/include/asm/irqflags.h

+0 −3
Original line number Diff line number Diff line
@@ -2,9 +2,6 @@ 
#define _M68K_IRQFLAGS_H



#include <linux/types.h>

#ifdef CONFIG_MMU

#include <linux/preempt_mask.h>

#endif

#include <linux/preempt.h>

#include <asm/thread_info.h>

#include <asm/entry.h>

include/linux/bottom_half.h

+0 −1
Original line number Diff line number Diff line
@@ -2,7 +2,6 @@ 
#define _LINUX_BH_H



#include <linux/preempt.h>

#include <linux/preempt_mask.h>



#ifdef CONFIG_TRACE_IRQFLAGS

extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);

include/linux/hardirq.h

+1 −1
Original line number Diff line number Diff line 
#ifndef LINUX_HARDIRQ_H

#define LINUX_HARDIRQ_H



#include <linux/preempt_mask.h>

#include <linux/preempt.h>

#include <linux/lockdep.h>

#include <linux/ftrace_irq.h>

#include <linux/vtime.h>

include/linux/preempt.h

+111 −0
Original line number Diff line number Diff line
@@ -17,6 +17,117 @@ 


#include <asm/preempt.h>



/*

 * We put the hardirq and softirq counter into the preemption

 * counter. The bitmask has the following meaning:

 *

 * - bits 0-7 are the preemption count (max preemption depth: 256)

 * - bits 8-15 are the softirq count (max # of softirqs: 256)

 *

 * The hardirq count could in theory be the same as the number of

 * interrupts in the system, but we run all interrupt handlers with

 * interrupts disabled, so we cannot have nesting interrupts. Though

 * there are a few palaeontologic drivers which reenable interrupts in

 * the handler, so we need more than one bit here.

 *

 * PREEMPT_MASK:	0x000000ff

 * SOFTIRQ_MASK:	0x0000ff00

 * HARDIRQ_MASK:	0x000f0000

 *     NMI_MASK:	0x00100000

 * PREEMPT_ACTIVE:	0x00200000

 */

#define PREEMPT_BITS	8

#define SOFTIRQ_BITS	8

#define HARDIRQ_BITS	4

#define NMI_BITS	1



#define PREEMPT_SHIFT	0

#define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)

#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)

#define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)



#define __IRQ_MASK(x)	((1UL << (x))-1)



#define PREEMPT_MASK	(__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)

#define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)

#define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)

#define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)



#define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)

#define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)

#define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)

#define NMI_OFFSET	(1UL << NMI_SHIFT)



#define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)



#define PREEMPT_ACTIVE_BITS	1

#define PREEMPT_ACTIVE_SHIFT	(NMI_SHIFT + NMI_BITS)

#define PREEMPT_ACTIVE	(__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)



#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)

#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)

#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \

				 | NMI_MASK))



/*

 * Are we doing bottom half or hardware interrupt processing?

 * Are we in a softirq context? Interrupt context?

 * in_softirq - Are we currently processing softirq or have bh disabled?

 * in_serving_softirq - Are we currently processing softirq?

 */

#define in_irq()		(hardirq_count())

#define in_softirq()		(softirq_count())

#define in_interrupt()		(irq_count())

#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)



/*

 * Are we in NMI context?

 */

#define in_nmi()	(preempt_count() & NMI_MASK)



#if defined(CONFIG_PREEMPT_COUNT)

# define PREEMPT_CHECK_OFFSET 1

#else

# define PREEMPT_CHECK_OFFSET 0

#endif



/*

 * The preempt_count offset needed for things like:

 *

 *  spin_lock_bh()

 *

 * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and

 * softirqs, such that unlock sequences of:

 *

 *  spin_unlock();

 *  local_bh_enable();

 *

 * Work as expected.

 */

#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_CHECK_OFFSET)



/*

 * Are we running in atomic context?  WARNING: this macro cannot

 * always detect atomic context; in particular, it cannot know about

 * held spinlocks in non-preemptible kernels.  Thus it should not be

 * used in the general case to determine whether sleeping is possible.

 * Do not use in_atomic() in driver code.

 */

#define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != 0)



/*

 * Check whether we were atomic before we did preempt_disable():

 * (used by the scheduler, *after* releasing the kernel lock)

 */

#define in_atomic_preempt_off() \

		((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)



#ifdef CONFIG_PREEMPT_COUNT

# define preemptible()	(preempt_count() == 0 && !irqs_disabled())

#else

# define preemptible()	0

#endif



#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)

extern void preempt_count_add(int val);

extern void preempt_count_sub(int val);

include/linux/preempt_mask.h

deleted100644 → 0
+0 −117
Original line number Diff line number Diff line 
#ifndef LINUX_PREEMPT_MASK_H

#define LINUX_PREEMPT_MASK_H



#include <linux/preempt.h>



/*

 * We put the hardirq and softirq counter into the preemption

 * counter. The bitmask has the following meaning:

 *

 * - bits 0-7 are the preemption count (max preemption depth: 256)

 * - bits 8-15 are the softirq count (max # of softirqs: 256)

 *

 * The hardirq count could in theory be the same as the number of

 * interrupts in the system, but we run all interrupt handlers with

 * interrupts disabled, so we cannot have nesting interrupts. Though

 * there are a few palaeontologic drivers which reenable interrupts in

 * the handler, so we need more than one bit here.

 *

 * PREEMPT_MASK:	0x000000ff

 * SOFTIRQ_MASK:	0x0000ff00

 * HARDIRQ_MASK:	0x000f0000

 *     NMI_MASK:	0x00100000

 * PREEMPT_ACTIVE:	0x00200000

 */

#define PREEMPT_BITS	8

#define SOFTIRQ_BITS	8

#define HARDIRQ_BITS	4

#define NMI_BITS	1



#define PREEMPT_SHIFT	0

#define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)

#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)

#define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)



#define __IRQ_MASK(x)	((1UL << (x))-1)



#define PREEMPT_MASK	(__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)

#define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)

#define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)

#define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)



#define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)

#define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)

#define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)

#define NMI_OFFSET	(1UL << NMI_SHIFT)



#define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)



#define PREEMPT_ACTIVE_BITS	1

#define PREEMPT_ACTIVE_SHIFT	(NMI_SHIFT + NMI_BITS)

#define PREEMPT_ACTIVE	(__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)



#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)

#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)

#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \

				 | NMI_MASK))



/*

 * Are we doing bottom half or hardware interrupt processing?

 * Are we in a softirq context? Interrupt context?

 * in_softirq - Are we currently processing softirq or have bh disabled?

 * in_serving_softirq - Are we currently processing softirq?

 */

#define in_irq()		(hardirq_count())

#define in_softirq()		(softirq_count())

#define in_interrupt()		(irq_count())

#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)



/*

 * Are we in NMI context?

 */

#define in_nmi()	(preempt_count() & NMI_MASK)



#if defined(CONFIG_PREEMPT_COUNT)

# define PREEMPT_CHECK_OFFSET 1

#else

# define PREEMPT_CHECK_OFFSET 0

#endif



/*

 * The preempt_count offset needed for things like:

 *

 *  spin_lock_bh()

 *

 * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and

 * softirqs, such that unlock sequences of:

 *

 *  spin_unlock();

 *  local_bh_enable();

 *

 * Work as expected.

 */

#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_CHECK_OFFSET)



/*

 * Are we running in atomic context?  WARNING: this macro cannot

 * always detect atomic context; in particular, it cannot know about

 * held spinlocks in non-preemptible kernels.  Thus it should not be

 * used in the general case to determine whether sleeping is possible.

 * Do not use in_atomic() in driver code.

 */

#define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != 0)



/*

 * Check whether we were atomic before we did preempt_disable():

 * (used by the scheduler, *after* releasing the kernel lock)

 */

#define in_atomic_preempt_off() \

		((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)



#ifdef CONFIG_PREEMPT_COUNT

# define preemptible()	(preempt_count() == 0 && !irqs_disabled())

#else

# define preemptible()	0

#endif



#endif /* LINUX_PREEMPT_MASK_H */