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Commit baa36046 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

cputime: Consolidate vtime handling on context switch 



The archs that implement virtual cputime accounting all
flush the cputime of a task when it gets descheduled
and sometimes set up some ground initialization for the
next task to account its cputime.

These archs all put their own hooks in their context
switch callbacks and handle the off-case themselves.

Consolidate this by creating a new account_switch_vtime()
callback called in generic code right after a context switch
and that these archs must implement to flush the prev task
cputime and initialize the next task cputime related state.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
parent 73fbec60

arch/ia64/include/asm/switch_to.h

+0 −8
Original line number Diff line number Diff line
@@ -30,13 +30,6 @@ extern struct task_struct *ia64_switch_to (void *next_task); 
extern void ia64_save_extra (struct task_struct *task);

extern void ia64_load_extra (struct task_struct *task);



#ifdef CONFIG_VIRT_CPU_ACCOUNTING

extern void ia64_account_on_switch (struct task_struct *prev, struct task_struct *next);

# define IA64_ACCOUNT_ON_SWITCH(p,n) ia64_account_on_switch(p,n)

#else

# define IA64_ACCOUNT_ON_SWITCH(p,n)

#endif



#ifdef CONFIG_PERFMON

  DECLARE_PER_CPU(unsigned long, pfm_syst_info);

# define PERFMON_IS_SYSWIDE() (__get_cpu_var(pfm_syst_info) & 0x1)
@@ -49,7 +42,6 @@ extern void ia64_account_on_switch (struct task_struct *prev, struct task_struct 
	 || PERFMON_IS_SYSWIDE())



#define __switch_to(prev,next,last) do {							 \

	IA64_ACCOUNT_ON_SWITCH(prev, next);							 \

	if (IA64_HAS_EXTRA_STATE(prev))								 \

		ia64_save_extra(prev);								 \

	if (IA64_HAS_EXTRA_STATE(next))								 \

arch/ia64/kernel/time.c

+2 −2
Original line number Diff line number Diff line
@@ -88,10 +88,10 @@ extern cputime_t cycle_to_cputime(u64 cyc); 
 * accumulated times to the current process, and to prepare accounting on

 * the next process.

 */

void ia64_account_on_switch(struct task_struct *prev, struct task_struct *next)

void account_switch_vtime(struct task_struct *prev)

{

	struct thread_info *pi = task_thread_info(prev);

	struct thread_info *ni = task_thread_info(next);

	struct thread_info *ni = task_thread_info(current);

	cputime_t delta_stime, delta_utime;

	__u64 now;

arch/powerpc/include/asm/time.h

+0 −6
Original line number Diff line number Diff line
@@ -197,12 +197,6 @@ struct cpu_usage { 


DECLARE_PER_CPU(struct cpu_usage, cpu_usage_array);



#if defined(CONFIG_VIRT_CPU_ACCOUNTING)

#define account_process_vtime(tsk)		account_process_tick(tsk, 0)

#else

#define account_process_vtime(tsk)		do { } while (0)

#endif



extern void secondary_cpu_time_init(void);



DECLARE_PER_CPU(u64, decrementers_next_tb);

arch/powerpc/kernel/process.c

+0 −3
Original line number Diff line number Diff line
@@ -514,9 +514,6 @@ struct task_struct *__switch_to(struct task_struct *prev, 


	local_irq_save(flags);



	account_system_vtime(current);

	account_process_vtime(current);



	/*

	 * We can't take a PMU exception inside _switch() since there is a

	 * window where the kernel stack SLB and the kernel stack are out

arch/powerpc/kernel/time.c

+6 −0
Original line number Diff line number Diff line
@@ -366,6 +366,12 @@ void account_process_tick(struct task_struct *tsk, int user_tick) 
	account_user_time(tsk, utime, utimescaled);

}



void account_switch_vtime(struct task_struct *prev)

{

	account_system_vtime(prev);

	account_process_tick(prev, 0);

}



#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */

#define calc_cputime_factors()

#endif