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OpenCloudOS-Kernel/include/linux/preempt.h

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#ifndef __LINUX_PREEMPT_H
#define __LINUX_PREEMPT_H
/*
* include/linux/preempt.h - macros for accessing and manipulating
* preempt_count (used for kernel preemption, interrupt count, etc.)
*/
#include <linux/linkage.h>
[PATCH] sched: arch preempt notifier mechanism This adds a general mechanism whereby a task can request the scheduler to notify it whenever it is preempted or scheduled back in. This allows the task to swap any special-purpose registers like the fpu or Intel's VT registers. Signed-off-by: Avi Kivity <avi@qumranet.com> [ mingo@elte.hu: fixes, cleanups ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-26 19:40:43 +08:00
#include <linux/list.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
sched: Add NEED_RESCHED to the preempt_count In order to combine the preemption and need_resched test we need to fold the need_resched information into the preempt_count value. Since the NEED_RESCHED flag is set across CPUs this needs to be an atomic operation, however we very much want to avoid making preempt_count atomic, therefore we keep the existing TIF_NEED_RESCHED infrastructure in place but at 3 sites test it and fold its value into preempt_count; namely: - resched_task() when setting TIF_NEED_RESCHED on the current task - scheduler_ipi() when resched_task() sets TIF_NEED_RESCHED on a remote task it follows it up with a reschedule IPI and we can modify the cpu local preempt_count from there. - cpu_idle_loop() for when resched_task() found tsk_is_polling(). We use an inverted bitmask to indicate need_resched so that a 0 means both need_resched and !atomic. Also remove the barrier() in preempt_enable() between preempt_enable_no_resched() and preempt_check_resched() to avoid having to reload the preemption value and allow the compiler to use the flags of the previuos decrement. I couldn't come up with any sane reason for this barrier() to be there as preempt_enable_no_resched() already has a barrier() before doing the decrement. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-7a7m5qqbn5pmwnd4wko9u6da@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:55:31 +08:00
/*
* We use the MSB mostly because its available; see <linux/preempt_mask.h> for
* the other bits -- can't include that header due to inclusion hell.
*/
#define PREEMPT_NEED_RESCHED 0x80000000
sched, arch: Create asm/preempt.h In order to prepare to per-arch implementations of preempt_count move the required bits into an asm-generic header and use this for all archs. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-h5j0c1r3e3fk015m30h8f1zx@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:55:40 +08:00
#include <asm/preempt.h>
sched: Add NEED_RESCHED to the preempt_count In order to combine the preemption and need_resched test we need to fold the need_resched information into the preempt_count value. Since the NEED_RESCHED flag is set across CPUs this needs to be an atomic operation, however we very much want to avoid making preempt_count atomic, therefore we keep the existing TIF_NEED_RESCHED infrastructure in place but at 3 sites test it and fold its value into preempt_count; namely: - resched_task() when setting TIF_NEED_RESCHED on the current task - scheduler_ipi() when resched_task() sets TIF_NEED_RESCHED on a remote task it follows it up with a reschedule IPI and we can modify the cpu local preempt_count from there. - cpu_idle_loop() for when resched_task() found tsk_is_polling(). We use an inverted bitmask to indicate need_resched so that a 0 means both need_resched and !atomic. Also remove the barrier() in preempt_enable() between preempt_enable_no_resched() and preempt_check_resched() to avoid having to reload the preemption value and allow the compiler to use the flags of the previuos decrement. I couldn't come up with any sane reason for this barrier() to be there as preempt_enable_no_resched() already has a barrier() before doing the decrement. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-7a7m5qqbn5pmwnd4wko9u6da@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:55:31 +08:00
ftrace: trace preempt off critical timings Add preempt off timings. A lot of kernel core code is taken from the RT patch latency trace that was written by Ingo Molnar. This adds "preemptoff" and "preemptirqsoff" to /debugfs/tracing/available_tracers Now instead of just tracing irqs off, preemption off can be selected to be recorded. When this is selected, it shares the same files as irqs off timings. One can either trace preemption off, irqs off, or one or the other off. By echoing "preemptoff" into /debugfs/tracing/current_tracer, recording of preempt off only is performed. "irqsoff" will only record the time irqs are disabled, but "preemptirqsoff" will take the total time irqs or preemption are disabled. Runtime switching of these options is now supported by simpling echoing in the appropriate trace name into /debugfs/tracing/current_tracer. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:42 +08:00
#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
extern void preempt_count_add(int val);
extern void preempt_count_sub(int val);
#define preempt_count_dec_and_test() ({ preempt_count_sub(1); should_resched(); })
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#else
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_count_add(val) __preempt_count_add(val)
#define preempt_count_sub(val) __preempt_count_sub(val)
#define preempt_count_dec_and_test() __preempt_count_dec_and_test()
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#endif
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define __preempt_count_inc() __preempt_count_add(1)
#define __preempt_count_dec() __preempt_count_sub(1)
sched: Isolate preempt counting in its own config option Create a new CONFIG_PREEMPT_COUNT that handles the inc/dec of preempt count offset independently. So that the offset can be updated by preempt_disable() and preempt_enable() even without the need for CONFIG_PREEMPT beeing set. This prepares to make CONFIG_DEBUG_SPINLOCK_SLEEP working with !CONFIG_PREEMPT where it currently doesn't detect code that sleeps inside explicit preemption disabled sections. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
2011-06-08 07:13:27 +08:00
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_count_inc() preempt_count_add(1)
#define preempt_count_dec() preempt_count_sub(1)
sched: Isolate preempt counting in its own config option Create a new CONFIG_PREEMPT_COUNT that handles the inc/dec of preempt count offset independently. So that the offset can be updated by preempt_disable() and preempt_enable() even without the need for CONFIG_PREEMPT beeing set. This prepares to make CONFIG_DEBUG_SPINLOCK_SLEEP working with !CONFIG_PREEMPT where it currently doesn't detect code that sleeps inside explicit preemption disabled sections. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
2011-06-08 07:13:27 +08:00
#ifdef CONFIG_PREEMPT_COUNT
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#define preempt_disable() \
do { \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
preempt_count_inc(); \
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
barrier(); \
} while (0)
sched/rt: Document scheduler related skip-resched-check sites Create a distinction between scheduler related preempt_enable_no_resched() calls and the nearly one hundred other places in the kernel that do not want to reschedule, for one reason or another. This distinction matters for -rt, where the scheduler and the non-scheduler preempt models (and checks) are different. For upstream it's purely documentational. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-gs88fvx2mdv5psnzxnv575ke@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-21 20:32:17 +08:00
#define sched_preempt_enable_no_resched() \
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
do { \
barrier(); \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
preempt_count_dec(); \
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
} while (0)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
sched/rt: Document scheduler related skip-resched-check sites Create a distinction between scheduler related preempt_enable_no_resched() calls and the nearly one hundred other places in the kernel that do not want to reschedule, for one reason or another. This distinction matters for -rt, where the scheduler and the non-scheduler preempt models (and checks) are different. For upstream it's purely documentational. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-gs88fvx2mdv5psnzxnv575ke@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-21 20:32:17 +08:00
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#ifdef CONFIG_PREEMPT
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#define preempt_enable() \
do { \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
barrier(); \
if (unlikely(preempt_count_dec_and_test())) \
sched, x86: Optimize the preempt_schedule() call Remove the bloat of the C calling convention out of the preempt_enable() sites by creating an ASM wrapper which allows us to do an asm("call ___preempt_schedule") instead. calling.h bits by Andi Kleen Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-tk7xdi1cvvxewixzke8t8le1@git.kernel.org [ Fixed build error. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:51:00 +08:00
__preempt_schedule(); \
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
} while (0)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_check_resched() \
do { \
if (should_resched()) \
sched, x86: Optimize the preempt_schedule() call Remove the bloat of the C calling convention out of the preempt_enable() sites by creating an ASM wrapper which allows us to do an asm("call ___preempt_schedule") instead. calling.h bits by Andi Kleen Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-tk7xdi1cvvxewixzke8t8le1@git.kernel.org [ Fixed build error. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:51:00 +08:00
__preempt_schedule(); \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
} while (0)
#else
sched/preempt: Take away preempt_enable_no_resched() from modules Discourage drivers/modules to be creative with preemption. Sadly all is implemented in macros and inline so if they want to do evil they still can, but at least try and discourage some. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com> Cc: rui.zhang@intel.com Cc: jacob.jun.pan@linux.intel.com Cc: Mike Galbraith <bitbucket@online.de> Cc: hpa@zytor.com Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: lenb@kernel.org Cc: rjw@rjwysocki.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-fn7h6vu8wtgxk0ih402qcijx@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-20 23:52:19 +08:00
#define preempt_enable() \
do { \
barrier(); \
preempt_count_dec(); \
} while (0)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_check_resched() do { } while (0)
#endif
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
#define preempt_disable_notrace() \
do { \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
__preempt_count_inc(); \
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
barrier(); \
} while (0)
#define preempt_enable_no_resched_notrace() \
do { \
barrier(); \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
__preempt_count_dec(); \
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
} while (0)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#ifdef CONFIG_PREEMPT
sched, x86: Optimize the preempt_schedule() call Remove the bloat of the C calling convention out of the preempt_enable() sites by creating an ASM wrapper which allows us to do an asm("call ___preempt_schedule") instead. calling.h bits by Andi Kleen Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-tk7xdi1cvvxewixzke8t8le1@git.kernel.org [ Fixed build error. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:51:00 +08:00
#ifndef CONFIG_CONTEXT_TRACKING
#define __preempt_schedule_context() __preempt_schedule()
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#endif
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
#define preempt_enable_notrace() \
do { \
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
barrier(); \
if (unlikely(__preempt_count_dec_and_test())) \
sched, x86: Optimize the preempt_schedule() call Remove the bloat of the C calling convention out of the preempt_enable() sites by creating an ASM wrapper which allows us to do an asm("call ___preempt_schedule") instead. calling.h bits by Andi Kleen Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-tk7xdi1cvvxewixzke8t8le1@git.kernel.org [ Fixed build error. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-14 20:51:00 +08:00
__preempt_schedule_context(); \
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
} while (0)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#else
sched/preempt: Take away preempt_enable_no_resched() from modules Discourage drivers/modules to be creative with preemption. Sadly all is implemented in macros and inline so if they want to do evil they still can, but at least try and discourage some. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com> Cc: rui.zhang@intel.com Cc: jacob.jun.pan@linux.intel.com Cc: Mike Galbraith <bitbucket@online.de> Cc: hpa@zytor.com Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: lenb@kernel.org Cc: rjw@rjwysocki.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-fn7h6vu8wtgxk0ih402qcijx@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-20 23:52:19 +08:00
#define preempt_enable_notrace() \
do { \
barrier(); \
__preempt_count_dec(); \
} while (0)
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#endif
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
sched: Isolate preempt counting in its own config option Create a new CONFIG_PREEMPT_COUNT that handles the inc/dec of preempt count offset independently. So that the offset can be updated by preempt_disable() and preempt_enable() even without the need for CONFIG_PREEMPT beeing set. This prepares to make CONFIG_DEBUG_SPINLOCK_SLEEP working with !CONFIG_PREEMPT where it currently doesn't detect code that sleeps inside explicit preemption disabled sections. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
2011-06-08 07:13:27 +08:00
#else /* !CONFIG_PREEMPT_COUNT */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
spinlocks and preemption points need to be at least compiler barriers In UP and non-preempt respectively, the spinlocks and preemption disable/enable points are stubbed out entirely, because there is no regular code that can ever hit the kind of concurrency they are meant to protect against. However, while there is no regular code that can cause scheduling, we _do_ end up having some exceptional (literally!) code that can do so, and that we need to make sure does not ever get moved into the critical region by the compiler. In particular, get_user() and put_user() is generally implemented as inline asm statements (even if the inline asm may then make a call instruction to call out-of-line), and can obviously cause a page fault and IO as a result. If that inline asm has been scheduled into the middle of a preemption-safe (or spinlock-protected) code region, we obviously lose. Now, admittedly this is *very* unlikely to actually ever happen, and we've not seen examples of actual bugs related to this. But partly exactly because it's so hard to trigger and the resulting bug is so subtle, we should be extra careful to get this right. So make sure that even when preemption is disabled, and we don't have to generate any actual *code* to explicitly tell the system that we are in a preemption-disabled region, we need to at least tell the compiler not to move things around the critical region. This patch grew out of the same discussion that caused commits 79e5f05edcbf ("ARC: Add implicit compiler barrier to raw_local_irq* functions") and 3e2e0d2c222b ("tile: comment assumption about __insn_mtspr for <asm/irqflags.h>") to come about. Note for stable: use discretion when/if applying this. As mentioned, this bug may never have actually bitten anybody, and gcc may never have done the required code motion for it to possibly ever trigger in practice. Cc: stable@vger.kernel.org Cc: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-10 01:48:33 +08:00
/*
* Even if we don't have any preemption, we need preempt disable/enable
* to be barriers, so that we don't have things like get_user/put_user
* that can cause faults and scheduling migrate into our preempt-protected
* region.
*/
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_disable() barrier()
spinlocks and preemption points need to be at least compiler barriers In UP and non-preempt respectively, the spinlocks and preemption disable/enable points are stubbed out entirely, because there is no regular code that can ever hit the kind of concurrency they are meant to protect against. However, while there is no regular code that can cause scheduling, we _do_ end up having some exceptional (literally!) code that can do so, and that we need to make sure does not ever get moved into the critical region by the compiler. In particular, get_user() and put_user() is generally implemented as inline asm statements (even if the inline asm may then make a call instruction to call out-of-line), and can obviously cause a page fault and IO as a result. If that inline asm has been scheduled into the middle of a preemption-safe (or spinlock-protected) code region, we obviously lose. Now, admittedly this is *very* unlikely to actually ever happen, and we've not seen examples of actual bugs related to this. But partly exactly because it's so hard to trigger and the resulting bug is so subtle, we should be extra careful to get this right. So make sure that even when preemption is disabled, and we don't have to generate any actual *code* to explicitly tell the system that we are in a preemption-disabled region, we need to at least tell the compiler not to move things around the critical region. This patch grew out of the same discussion that caused commits 79e5f05edcbf ("ARC: Add implicit compiler barrier to raw_local_irq* functions") and 3e2e0d2c222b ("tile: comment assumption about __insn_mtspr for <asm/irqflags.h>") to come about. Note for stable: use discretion when/if applying this. As mentioned, this bug may never have actually bitten anybody, and gcc may never have done the required code motion for it to possibly ever trigger in practice. Cc: stable@vger.kernel.org Cc: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-10 01:48:33 +08:00
#define sched_preempt_enable_no_resched() barrier()
sched: Extract the basic add/sub preempt_count modifiers Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-10 18:15:23 +08:00
#define preempt_enable_no_resched() barrier()
#define preempt_enable() barrier()
#define preempt_check_resched() do { } while (0)
spinlocks and preemption points need to be at least compiler barriers In UP and non-preempt respectively, the spinlocks and preemption disable/enable points are stubbed out entirely, because there is no regular code that can ever hit the kind of concurrency they are meant to protect against. However, while there is no regular code that can cause scheduling, we _do_ end up having some exceptional (literally!) code that can do so, and that we need to make sure does not ever get moved into the critical region by the compiler. In particular, get_user() and put_user() is generally implemented as inline asm statements (even if the inline asm may then make a call instruction to call out-of-line), and can obviously cause a page fault and IO as a result. If that inline asm has been scheduled into the middle of a preemption-safe (or spinlock-protected) code region, we obviously lose. Now, admittedly this is *very* unlikely to actually ever happen, and we've not seen examples of actual bugs related to this. But partly exactly because it's so hard to trigger and the resulting bug is so subtle, we should be extra careful to get this right. So make sure that even when preemption is disabled, and we don't have to generate any actual *code* to explicitly tell the system that we are in a preemption-disabled region, we need to at least tell the compiler not to move things around the critical region. This patch grew out of the same discussion that caused commits 79e5f05edcbf ("ARC: Add implicit compiler barrier to raw_local_irq* functions") and 3e2e0d2c222b ("tile: comment assumption about __insn_mtspr for <asm/irqflags.h>") to come about. Note for stable: use discretion when/if applying this. As mentioned, this bug may never have actually bitten anybody, and gcc may never have done the required code motion for it to possibly ever trigger in practice. Cc: stable@vger.kernel.org Cc: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-10 01:48:33 +08:00
#define preempt_disable_notrace() barrier()
#define preempt_enable_no_resched_notrace() barrier()
#define preempt_enable_notrace() barrier()
ftrace: add preempt_enable/disable notrace macros The tracer may need to call preempt_enable and disable functions for time keeping and such. The trace gets ugly when we see these functions show up for all traces. To make the output cleaner this patch adds preempt_enable_notrace and preempt_disable_notrace to be used by tracer (and debugging) functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-13 03:20:41 +08:00
sched: Isolate preempt counting in its own config option Create a new CONFIG_PREEMPT_COUNT that handles the inc/dec of preempt count offset independently. So that the offset can be updated by preempt_disable() and preempt_enable() even without the need for CONFIG_PREEMPT beeing set. This prepares to make CONFIG_DEBUG_SPINLOCK_SLEEP working with !CONFIG_PREEMPT where it currently doesn't detect code that sleeps inside explicit preemption disabled sections. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
2011-06-08 07:13:27 +08:00
#endif /* CONFIG_PREEMPT_COUNT */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
sched/preempt: Take away preempt_enable_no_resched() from modules Discourage drivers/modules to be creative with preemption. Sadly all is implemented in macros and inline so if they want to do evil they still can, but at least try and discourage some. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com> Cc: rui.zhang@intel.com Cc: jacob.jun.pan@linux.intel.com Cc: Mike Galbraith <bitbucket@online.de> Cc: hpa@zytor.com Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: lenb@kernel.org Cc: rjw@rjwysocki.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-fn7h6vu8wtgxk0ih402qcijx@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-20 23:52:19 +08:00
#ifdef MODULE
/*
* Modules have no business playing preemption tricks.
*/
#undef sched_preempt_enable_no_resched
#undef preempt_enable_no_resched
#undef preempt_enable_no_resched_notrace
#undef preempt_check_resched
#endif
sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding With various drivers wanting to inject idle time; we get people calling idle routines outside of the idle loop proper. Therefore we need to be extra careful about not missing TIF_NEED_RESCHED -> PREEMPT_NEED_RESCHED propagations. While looking at this, I also realized there's a small window in the existing idle loop where we can miss TIF_NEED_RESCHED; when it hits right after the tif_need_resched() test at the end of the loop but right before the need_resched() test at the start of the loop. So move preempt_fold_need_resched() out of the loop where we're guaranteed to have TIF_NEED_RESCHED set. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-x9jgh45oeayzajz2mjt0y7d6@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-20 19:22:37 +08:00
#define preempt_set_need_resched() \
do { \
set_preempt_need_resched(); \
} while (0)
#define preempt_fold_need_resched() \
do { \
if (tif_need_resched()) \
set_preempt_need_resched(); \
} while (0)
[PATCH] sched: arch preempt notifier mechanism This adds a general mechanism whereby a task can request the scheduler to notify it whenever it is preempted or scheduled back in. This allows the task to swap any special-purpose registers like the fpu or Intel's VT registers. Signed-off-by: Avi Kivity <avi@qumranet.com> [ mingo@elte.hu: fixes, cleanups ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-26 19:40:43 +08:00
#ifdef CONFIG_PREEMPT_NOTIFIERS
struct preempt_notifier;
/**
* preempt_ops - notifiers called when a task is preempted and rescheduled
* @sched_in: we're about to be rescheduled:
* notifier: struct preempt_notifier for the task being scheduled
* cpu: cpu we're scheduled on
* @sched_out: we've just been preempted
* notifier: struct preempt_notifier for the task being preempted
* next: the task that's kicking us out
sched: Revert 498657a478c60be092208422fefa9c7b248729c2 498657a478c60be092208422fefa9c7b248729c2 incorrectly assumed that preempt wasn't disabled around context_switch() and thus was fixing imaginary problem. It also broke KVM because it depended on ->sched_in() to be called with irq enabled so that it can do smp calls from there. Revert the incorrect commit and add comment describing different contexts under with the two callbacks are invoked. Avi: spotted transposed in/out in the added comment. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Avi Kivity <avi@redhat.com> Cc: peterz@infradead.org Cc: efault@gmx.de Cc: rusty@rustcorp.com.au LKML-Reference: <1259726212-30259-2-git-send-email-tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-02 11:56:46 +08:00
*
* Please note that sched_in and out are called under different
* contexts. sched_out is called with rq lock held and irq disabled
* while sched_in is called without rq lock and irq enabled. This
* difference is intentional and depended upon by its users.
[PATCH] sched: arch preempt notifier mechanism This adds a general mechanism whereby a task can request the scheduler to notify it whenever it is preempted or scheduled back in. This allows the task to swap any special-purpose registers like the fpu or Intel's VT registers. Signed-off-by: Avi Kivity <avi@qumranet.com> [ mingo@elte.hu: fixes, cleanups ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-26 19:40:43 +08:00
*/
struct preempt_ops {
void (*sched_in)(struct preempt_notifier *notifier, int cpu);
void (*sched_out)(struct preempt_notifier *notifier,
struct task_struct *next);
};
/**
* preempt_notifier - key for installing preemption notifiers
* @link: internal use
* @ops: defines the notifier functions to be called
*
* Usually used in conjunction with container_of().
*/
struct preempt_notifier {
struct hlist_node link;
struct preempt_ops *ops;
};
void preempt_notifier_register(struct preempt_notifier *notifier);
void preempt_notifier_unregister(struct preempt_notifier *notifier);
static inline void preempt_notifier_init(struct preempt_notifier *notifier,
struct preempt_ops *ops)
{
INIT_HLIST_NODE(&notifier->link);
notifier->ops = ops;
}
#endif
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#endif /* __LINUX_PREEMPT_H */