sched/preempt: Use CONFIG_PREEMPTION where appropriate
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the preemption code, scheduler and init task over to use CONFIG_PREEMPTION. That's the first step towards RT in that area. The more complex changes are coming separately. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20190726212124.117528401@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -78,11 +78,11 @@ static __always_inline bool should_resched(int preempt_offset)
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tif_need_resched());
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}
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPTION
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extern asmlinkage void preempt_schedule(void);
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#define __preempt_schedule() preempt_schedule()
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extern asmlinkage void preempt_schedule_notrace(void);
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#define __preempt_schedule_notrace() preempt_schedule_notrace()
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#endif /* CONFIG_PREEMPT */
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#endif /* CONFIG_PREEMPTION */
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#endif /* __ASM_PREEMPT_H */
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@ -182,7 +182,7 @@ do { \
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#define preemptible() (preempt_count() == 0 && !irqs_disabled())
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPTION
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#define preempt_enable() \
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do { \
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barrier(); \
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@ -203,7 +203,7 @@ do { \
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__preempt_schedule(); \
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} while (0)
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#else /* !CONFIG_PREEMPT */
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#else /* !CONFIG_PREEMPTION */
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#define preempt_enable() \
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do { \
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barrier(); \
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@ -217,7 +217,7 @@ do { \
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} while (0)
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#define preempt_check_resched() do { } while (0)
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#endif /* CONFIG_PREEMPT */
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#endif /* CONFIG_PREEMPTION */
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#define preempt_disable_notrace() \
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do { \
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@ -1767,7 +1767,7 @@ static inline int test_tsk_need_resched(struct task_struct *tsk)
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* value indicates whether a reschedule was done in fact.
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* cond_resched_lock() will drop the spinlock before scheduling,
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*/
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#ifndef CONFIG_PREEMPT
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#ifndef CONFIG_PREEMPTION
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extern int _cond_resched(void);
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#else
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static inline int _cond_resched(void) { return 0; }
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@ -1796,12 +1796,12 @@ static inline void cond_resched_rcu(void)
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/*
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* Does a critical section need to be broken due to another
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* task waiting?: (technically does not depend on CONFIG_PREEMPT,
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* task waiting?: (technically does not depend on CONFIG_PREEMPTION,
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* but a general need for low latency)
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*/
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static inline int spin_needbreak(spinlock_t *lock)
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{
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPTION
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return spin_is_contended(lock);
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#else
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return 0;
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@ -174,7 +174,7 @@ struct task_struct init_task
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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.ret_stack = NULL,
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#endif
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#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPT)
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#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPTION)
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.trace_recursion = 0,
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#endif
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#ifdef CONFIG_LIVEPATCH
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@ -433,7 +433,7 @@ noinline void __ref rest_init(void)
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/*
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* Enable might_sleep() and smp_processor_id() checks.
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* They cannot be enabled earlier because with CONFIG_PREEMPT=y
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* They cannot be enabled earlier because with CONFIG_PREEMPTION=y
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* kernel_thread() would trigger might_sleep() splats. With
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* CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
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* already, but it's stuck on the kthreadd_done completion.
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@ -3581,7 +3581,7 @@ static inline void sched_tick_start(int cpu) { }
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static inline void sched_tick_stop(int cpu) { }
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#endif
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#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
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#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
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defined(CONFIG_TRACE_PREEMPT_TOGGLE))
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/*
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* If the value passed in is equal to the current preempt count
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@ -3782,7 +3782,7 @@ again:
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* task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
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* called on the nearest possible occasion:
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*
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* - If the kernel is preemptible (CONFIG_PREEMPT=y):
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* - If the kernel is preemptible (CONFIG_PREEMPTION=y):
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*
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* - in syscall or exception context, at the next outmost
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* preempt_enable(). (this might be as soon as the wake_up()'s
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@ -3791,7 +3791,7 @@ again:
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* - in IRQ context, return from interrupt-handler to
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* preemptible context
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*
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* - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
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* - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
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* then at the next:
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*
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* - cond_resched() call
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@ -4033,7 +4033,7 @@ static void __sched notrace preempt_schedule_common(void)
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} while (need_resched());
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}
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPTION
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/*
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* this is the entry point to schedule() from in-kernel preemption
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* off of preempt_enable. Kernel preemptions off return from interrupt
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@ -4105,7 +4105,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
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}
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EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
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#endif /* CONFIG_PREEMPT */
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#endif /* CONFIG_PREEMPTION */
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/*
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* this is the entry point to schedule() from kernel preemption
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@ -5416,7 +5416,7 @@ SYSCALL_DEFINE0(sched_yield)
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return 0;
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}
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#ifndef CONFIG_PREEMPT
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#ifndef CONFIG_PREEMPTION
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int __sched _cond_resched(void)
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{
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if (should_resched(0)) {
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@ -5433,7 +5433,7 @@ EXPORT_SYMBOL(_cond_resched);
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* __cond_resched_lock() - if a reschedule is pending, drop the given lock,
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* call schedule, and on return reacquire the lock.
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*
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* This works OK both with and without CONFIG_PREEMPT. We do strange low-level
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* This works OK both with and without CONFIG_PREEMPTION. We do strange low-level
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* operations here to prevent schedule() from being called twice (once via
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* spin_unlock(), once by hand).
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*/
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@ -7430,7 +7430,7 @@ static int detach_tasks(struct lb_env *env)
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detached++;
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env->imbalance -= load;
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPTION
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/*
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* NEWIDLE balancing is a source of latency, so preemptible
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* kernels will stop after the first task is detached to minimize
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@ -1943,7 +1943,7 @@ unsigned long arch_scale_freq_capacity(int cpu)
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#endif
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#ifdef CONFIG_SMP
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPTION
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static inline void double_rq_lock(struct rq *rq1, struct rq *rq2);
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@ -1995,7 +1995,7 @@ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
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return ret;
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}
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#endif /* CONFIG_PREEMPT */
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#endif /* CONFIG_PREEMPTION */
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/*
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* double_lock_balance - lock the busiest runqueue, this_rq is locked already.
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