023e9deb51
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>
119 lines
3.6 KiB
C
119 lines
3.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_KERNEL_VTIME_H
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#define _LINUX_KERNEL_VTIME_H
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#include <linux/context_tracking_state.h>
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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#include <asm/vtime.h>
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#endif
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struct task_struct;
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/*
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* vtime_accounting_enabled_this_cpu() definitions/declarations
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*/
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#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE)
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static inline bool vtime_accounting_enabled_this_cpu(void) { return true; }
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extern void vtime_task_switch(struct task_struct *prev);
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#elif defined(CONFIG_VIRT_CPU_ACCOUNTING_GEN)
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/*
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* Checks if vtime is enabled on some CPU. Cputime readers want to be careful
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* in that case and compute the tickless cputime.
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* For now vtime state is tied to context tracking. We might want to decouple
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* those later if necessary.
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*/
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static inline bool vtime_accounting_enabled(void)
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{
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return context_tracking_enabled();
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}
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static inline bool vtime_accounting_enabled_cpu(int cpu)
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{
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return context_tracking_enabled_cpu(cpu);
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}
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static inline bool vtime_accounting_enabled_this_cpu(void)
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{
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return context_tracking_enabled_this_cpu();
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}
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extern void vtime_task_switch_generic(struct task_struct *prev);
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static inline void vtime_task_switch(struct task_struct *prev)
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{
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if (vtime_accounting_enabled_this_cpu())
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vtime_task_switch_generic(prev);
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}
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#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
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static inline bool vtime_accounting_enabled_cpu(int cpu) {return false; }
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static inline bool vtime_accounting_enabled_this_cpu(void) { return false; }
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static inline void vtime_task_switch(struct task_struct *prev) { }
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#endif
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/*
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* Common vtime APIs
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*/
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING
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extern void vtime_account_kernel(struct task_struct *tsk);
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extern void vtime_account_idle(struct task_struct *tsk);
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#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
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static inline void vtime_account_kernel(struct task_struct *tsk) { }
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#endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
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extern void arch_vtime_task_switch(struct task_struct *tsk);
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extern void vtime_user_enter(struct task_struct *tsk);
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extern void vtime_user_exit(struct task_struct *tsk);
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extern void vtime_guest_enter(struct task_struct *tsk);
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extern void vtime_guest_exit(struct task_struct *tsk);
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extern void vtime_init_idle(struct task_struct *tsk, int cpu);
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#else /* !CONFIG_VIRT_CPU_ACCOUNTING_GEN */
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static inline void vtime_user_enter(struct task_struct *tsk) { }
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static inline void vtime_user_exit(struct task_struct *tsk) { }
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static inline void vtime_guest_enter(struct task_struct *tsk) { }
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static inline void vtime_guest_exit(struct task_struct *tsk) { }
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static inline void vtime_init_idle(struct task_struct *tsk, int cpu) { }
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#endif
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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extern void vtime_account_irq_enter(struct task_struct *tsk);
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static inline void vtime_account_irq_exit(struct task_struct *tsk)
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{
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/* On hard|softirq exit we always account to hard|softirq cputime */
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vtime_account_kernel(tsk);
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}
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extern void vtime_flush(struct task_struct *tsk);
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#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
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static inline void vtime_account_irq_enter(struct task_struct *tsk) { }
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static inline void vtime_account_irq_exit(struct task_struct *tsk) { }
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static inline void vtime_flush(struct task_struct *tsk) { }
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#endif
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#ifdef CONFIG_IRQ_TIME_ACCOUNTING
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extern void irqtime_account_irq(struct task_struct *tsk);
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#else
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static inline void irqtime_account_irq(struct task_struct *tsk) { }
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#endif
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static inline void account_irq_enter_time(struct task_struct *tsk)
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{
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vtime_account_irq_enter(tsk);
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irqtime_account_irq(tsk);
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}
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static inline void account_irq_exit_time(struct task_struct *tsk)
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{
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vtime_account_irq_exit(tsk);
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irqtime_account_irq(tsk);
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}
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#endif /* _LINUX_KERNEL_VTIME_H */
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