diff options
author | Frederic Weisbecker <fweisbec@gmail.com> | 2012-12-16 20:00:34 +0100 |
---|---|---|
committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-01-27 20:35:47 +0100 |
commit | 6a61671bb2f3a1bd12cd17b8fca811a624782632 (patch) | |
tree | 0afc2915fb7e517472710a49a524510322dd5baa /include/linux/vtime.h | |
parent | c11f11fcbdb5be790c565aed46411486a7586afc (diff) | |
download | linux-stable-6a61671bb2f3a1bd12cd17b8fca811a624782632.tar.gz linux-stable-6a61671bb2f3a1bd12cd17b8fca811a624782632.tar.bz2 linux-stable-6a61671bb2f3a1bd12cd17b8fca811a624782632.zip |
cputime: Safely read cputime of full dynticks CPUs
While remotely reading the cputime of a task running in a
full dynticks CPU, the values stored in utime/stime fields
of struct task_struct may be stale. Its values may be those
of the last kernel <-> user transition time snapshot and
we need to add the tickless time spent since this snapshot.
To fix this, flush the cputime of the dynticks CPUs on
kernel <-> user transition and record the time / context
where we did this. Then on top of this snapshot and the current
time, perform the fixup on the reader side from task_times()
accessors.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[fixed kvm module related build errors]
Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Diffstat (limited to 'include/linux/vtime.h')
-rw-r--r-- | include/linux/vtime.h | 47 |
1 files changed, 23 insertions, 24 deletions
diff --git a/include/linux/vtime.h b/include/linux/vtime.h index bb50c3ca0d79..71a5782d8c59 100644 --- a/include/linux/vtime.h +++ b/include/linux/vtime.h @@ -8,35 +8,44 @@ extern void vtime_task_switch(struct task_struct *prev); extern void vtime_account_system(struct task_struct *tsk); extern void vtime_account_idle(struct task_struct *tsk); extern void vtime_account_user(struct task_struct *tsk); -extern void vtime_account(struct task_struct *tsk); +extern void vtime_account_irq_enter(struct task_struct *tsk); -#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN -extern bool vtime_accounting_enabled(void); -#else +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE static inline bool vtime_accounting_enabled(void) { return true; } #endif #else /* !CONFIG_VIRT_CPU_ACCOUNTING */ + static inline void vtime_task_switch(struct task_struct *prev) { } static inline void vtime_account_system(struct task_struct *tsk) { } static inline void vtime_account_user(struct task_struct *tsk) { } -static inline void vtime_account(struct task_struct *tsk) { } +static inline void vtime_account_irq_enter(struct task_struct *tsk) { } static inline bool vtime_accounting_enabled(void) { return false; } #endif #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN -static inline void arch_vtime_task_switch(struct task_struct *tsk) { } -static inline void vtime_user_enter(struct task_struct *tsk) -{ - vtime_account_system(tsk); -} +extern void arch_vtime_task_switch(struct task_struct *tsk); +extern void vtime_account_irq_exit(struct task_struct *tsk); +extern bool vtime_accounting_enabled(void); +extern void vtime_user_enter(struct task_struct *tsk); static inline void vtime_user_exit(struct task_struct *tsk) { vtime_account_user(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); #else +static inline void vtime_account_irq_exit(struct task_struct *tsk) +{ + /* On hard|softirq exit we always account to hard|softirq cputime */ + vtime_account_system(tsk); +} 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) { } #endif #ifdef CONFIG_IRQ_TIME_ACCOUNTING @@ -45,25 +54,15 @@ extern void irqtime_account_irq(struct task_struct *tsk); static inline void irqtime_account_irq(struct task_struct *tsk) { } #endif -static inline void vtime_account_irq_enter(struct task_struct *tsk) +static inline void account_irq_enter_time(struct task_struct *tsk) { - /* - * Hardirq can interrupt idle task anytime. So we need vtime_account() - * that performs the idle check in CONFIG_VIRT_CPU_ACCOUNTING. - * Softirq can also interrupt idle task directly if it calls - * local_bh_enable(). Such case probably don't exist but we never know. - * Ksoftirqd is not concerned because idle time is flushed on context - * switch. Softirqs in the end of hardirqs are also not a problem because - * the idle time is flushed on hardirq time already. - */ - vtime_account(tsk); + vtime_account_irq_enter(tsk); irqtime_account_irq(tsk); } -static inline void vtime_account_irq_exit(struct task_struct *tsk) +static inline void account_irq_exit_time(struct task_struct *tsk) { - /* On hard|softirq exit we always account to hard|softirq cputime */ - vtime_account_system(tsk); + vtime_account_irq_exit(tsk); irqtime_account_irq(tsk); } |