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38d707c54d
The cpu_idle_type enum has the confusingly inverted property that 'not idle' is 1, and 'idle' is '0'. This resulted in a number of unnecessary complications in the code. Reverse the order, remove the CPU_NOT_IDLE type, and convert all code to a natural boolean form. It's much more readable: - enum cpu_idle_type idle = this_rq->idle_balance ? - CPU_IDLE : CPU_NOT_IDLE; - + enum cpu_idle_type idle = this_rq->idle_balance; -------------------------------- - if (env->idle == CPU_NOT_IDLE || !busiest->sum_nr_running) + if (!env->idle || !busiest->sum_nr_running) -------------------------------- And gets rid of the double negation in these usages: - if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1) + if (env->idle && env->src_rq->nr_running <= 1) Furthermore, this makes code much more obvious where there's differentiation between CPU_IDLE and CPU_NEWLY_IDLE. Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Valentin Schneider <vschneid@redhat.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: "Gautham R. Shenoy" <gautham.shenoy@amd.com> Link: https://lore.kernel.org/r/20240308105901.1096078-4-mingo@kernel.org
112 lines
2.4 KiB
C
112 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_IDLE_H
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#define _LINUX_SCHED_IDLE_H
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#include <linux/sched.h>
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enum cpu_idle_type {
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__CPU_NOT_IDLE = 0,
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CPU_IDLE,
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CPU_NEWLY_IDLE,
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CPU_MAX_IDLE_TYPES
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};
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#ifdef CONFIG_SMP
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extern void wake_up_if_idle(int cpu);
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#else
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static inline void wake_up_if_idle(int cpu) { }
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#endif
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/*
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* Idle thread specific functions to determine the need_resched
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* polling state.
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*/
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#ifdef TIF_POLLING_NRFLAG
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#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H
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static __always_inline void __current_set_polling(void)
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{
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arch_set_bit(TIF_POLLING_NRFLAG,
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(unsigned long *)(¤t_thread_info()->flags));
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}
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static __always_inline void __current_clr_polling(void)
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{
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arch_clear_bit(TIF_POLLING_NRFLAG,
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(unsigned long *)(¤t_thread_info()->flags));
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}
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#else
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static __always_inline void __current_set_polling(void)
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{
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set_bit(TIF_POLLING_NRFLAG,
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(unsigned long *)(¤t_thread_info()->flags));
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}
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static __always_inline void __current_clr_polling(void)
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{
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clear_bit(TIF_POLLING_NRFLAG,
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(unsigned long *)(¤t_thread_info()->flags));
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}
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#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H */
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static __always_inline bool __must_check current_set_polling_and_test(void)
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{
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__current_set_polling();
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/*
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* Polling state must be visible before we test NEED_RESCHED,
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* paired by resched_curr()
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*/
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smp_mb__after_atomic();
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return unlikely(tif_need_resched());
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}
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static __always_inline bool __must_check current_clr_polling_and_test(void)
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{
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__current_clr_polling();
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/*
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* Polling state must be visible before we test NEED_RESCHED,
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* paired by resched_curr()
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*/
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smp_mb__after_atomic();
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return unlikely(tif_need_resched());
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}
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#else
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static inline void __current_set_polling(void) { }
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static inline void __current_clr_polling(void) { }
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static inline bool __must_check current_set_polling_and_test(void)
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{
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return unlikely(tif_need_resched());
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}
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static inline bool __must_check current_clr_polling_and_test(void)
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{
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return unlikely(tif_need_resched());
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}
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#endif
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static __always_inline void current_clr_polling(void)
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{
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__current_clr_polling();
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/*
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* Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
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* Once the bit is cleared, we'll get IPIs with every new
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* TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
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* fold.
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*/
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smp_mb(); /* paired with resched_curr() */
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preempt_fold_need_resched();
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}
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#endif /* _LINUX_SCHED_IDLE_H */
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