linux_dsm_epyc7002/include/linux/sched/nohz.h
Peter Zijlstra 00357f5ec5 sched/nohz: Clean up nohz enter/exit
The primary observation is that nohz enter/exit is always from the
current CPU, therefore NOHZ_TICK_STOPPED does not in fact need to be
an atomic.

Secondary is that we appear to have 2 nearly identical hooks in the
nohz enter code, set_cpu_sd_state_idle() and
nohz_balance_enter_idle(). Fold the whole set_cpu_sd_state thing into
nohz_balance_{enter,exit}_idle.

Removes an atomic op from both enter and exit paths.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-09 07:59:19 +01:00

39 lines
1.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCHED_NOHZ_H
#define _LINUX_SCHED_NOHZ_H
/*
* This is the interface between the scheduler and nohz/dynticks:
*/
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
extern void cpu_load_update_nohz_start(void);
extern void cpu_load_update_nohz_stop(void);
#else
static inline void cpu_load_update_nohz_start(void) { }
static inline void cpu_load_update_nohz_stop(void) { }
#endif
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
extern void nohz_balance_enter_idle(int cpu);
extern int get_nohz_timer_target(void);
#else
static inline void nohz_balance_enter_idle(int cpu) { }
#endif
#ifdef CONFIG_NO_HZ_COMMON
void calc_load_nohz_start(void);
void calc_load_nohz_stop(void);
#else
static inline void calc_load_nohz_start(void) { }
static inline void calc_load_nohz_stop(void) { }
#endif /* CONFIG_NO_HZ_COMMON */
#if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
extern void wake_up_nohz_cpu(int cpu);
#else
static inline void wake_up_nohz_cpu(int cpu) { }
#endif
#endif /* _LINUX_SCHED_NOHZ_H */