linux-stable/include/linux/vtime.h
Frederic Weisbecker 023e9deb51 context_tracking: Check static key on context_tracking_enabled_*cpu()
guest_enter() doesn't call context_tracking_enabled() before calling
context_tracking_enabled_this_cpu(). Therefore the guest code doesn't
benefit from the static key on the fast path.

Just make sure that context_tracking_enabled_*cpu() functions check
the static key by themselves to propagate the optimization.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J . Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Link: https://lkml.kernel.org/r/20191016025700.31277-11-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-29 10:01:16 +01:00

118 lines
3.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_KERNEL_VTIME_H
#define _LINUX_KERNEL_VTIME_H
#include <linux/context_tracking_state.h>
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
#include <asm/vtime.h>
#endif
struct task_struct;
/*
* vtime_accounting_enabled_this_cpu() definitions/declarations
*/
#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE)
static inline bool vtime_accounting_enabled_this_cpu(void) { return true; }
extern void vtime_task_switch(struct task_struct *prev);
#elif defined(CONFIG_VIRT_CPU_ACCOUNTING_GEN)
/*
* Checks if vtime is enabled on some CPU. Cputime readers want to be careful
* in that case and compute the tickless cputime.
* For now vtime state is tied to context tracking. We might want to decouple
* those later if necessary.
*/
static inline bool vtime_accounting_enabled(void)
{
return context_tracking_enabled();
}
static inline bool vtime_accounting_enabled_cpu(int cpu)
{
return context_tracking_enabled_cpu(cpu);
}
static inline bool vtime_accounting_enabled_this_cpu(void)
{
return context_tracking_enabled_this_cpu();
}
extern void vtime_task_switch_generic(struct task_struct *prev);
static inline void vtime_task_switch(struct task_struct *prev)
{
if (vtime_accounting_enabled_this_cpu())
vtime_task_switch_generic(prev);
}
#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
static inline bool vtime_accounting_enabled_cpu(int cpu) {return false; }
static inline bool vtime_accounting_enabled_this_cpu(void) { return false; }
static inline void vtime_task_switch(struct task_struct *prev) { }
#endif
/*
* Common vtime APIs
*/
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
extern void vtime_account_kernel(struct task_struct *tsk);
extern void vtime_account_idle(struct task_struct *tsk);
#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
static inline void vtime_account_kernel(struct task_struct *tsk) { }
#endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
extern void arch_vtime_task_switch(struct task_struct *tsk);
extern void vtime_user_enter(struct task_struct *tsk);
extern void vtime_user_exit(struct task_struct *tsk);
extern void vtime_guest_enter(struct task_struct *tsk);
extern void vtime_guest_exit(struct task_struct *tsk);
extern void vtime_init_idle(struct task_struct *tsk, int cpu);
#else /* !CONFIG_VIRT_CPU_ACCOUNTING_GEN */
static inline void vtime_user_enter(struct task_struct *tsk) { }
static inline void vtime_user_exit(struct task_struct *tsk) { }
static inline void vtime_guest_enter(struct task_struct *tsk) { }
static inline void vtime_guest_exit(struct task_struct *tsk) { }
static inline void vtime_init_idle(struct task_struct *tsk, int cpu) { }
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
extern void vtime_account_irq_enter(struct task_struct *tsk);
static inline void vtime_account_irq_exit(struct task_struct *tsk)
{
/* On hard|softirq exit we always account to hard|softirq cputime */
vtime_account_kernel(tsk);
}
extern void vtime_flush(struct task_struct *tsk);
#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
static inline void vtime_account_irq_enter(struct task_struct *tsk) { }
static inline void vtime_account_irq_exit(struct task_struct *tsk) { }
static inline void vtime_flush(struct task_struct *tsk) { }
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
extern void irqtime_account_irq(struct task_struct *tsk);
#else
static inline void irqtime_account_irq(struct task_struct *tsk) { }
#endif
static inline void account_irq_enter_time(struct task_struct *tsk)
{
vtime_account_irq_enter(tsk);
irqtime_account_irq(tsk);
}
static inline void account_irq_exit_time(struct task_struct *tsk)
{
vtime_account_irq_exit(tsk);
irqtime_account_irq(tsk);
}
#endif /* _LINUX_KERNEL_VTIME_H */