| Subject | Re: [PATCH 03/33] cputime: Generic on-demand virtual cputime accounting | From | Steven Rostedt <> | Date | Tue, 08 Jan 2013 15:23:31 -0500 |
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On Tue, 2013-01-08 at 03:08 +0100, Frederic Weisbecker wrote:
> +++ b/kernel/sched/cputime.c > @@ -3,6 +3,7 @@ > #include <linux/tsacct_kern.h> > #include <linux/kernel_stat.h> > #include <linux/static_key.h> > +#include <linux/context_tracking.h> > #include "sched.h" > > > @@ -495,10 +496,24 @@ void vtime_task_switch(struct task_struct *prev) > #ifndef __ARCH_HAS_VTIME_ACCOUNT > void vtime_account(struct task_struct *tsk) > { > - if (in_interrupt() || !is_idle_task(tsk)) > - vtime_account_system(tsk); > - else > - vtime_account_idle(tsk); > + if (!in_interrupt()) { > + /* > + * If we interrupted user, context_tracking_in_user() > + * is 1 because the context tracking don't hook
s/don't/doesn't/
> + * on irq entry/exit. This way we know if > + * we need to flush user time on kernel entry.
Also, the above comment is simply confusing. Why not just say something like:
Context tracking doesn't hook on irq entry/exit. The context will still be user context if the interrupt preempted user space.
No need to explain the implementation details of "context_tracing_in_user() is 1 ...".
-- Steve
> + */ > + if (context_tracking_in_user()) { > + vtime_account_user(tsk); > + return; > + } > + > + if (is_idle_task(tsk)) { > + vtime_account_idle(tsk); > + return; > + } > + } > + vtime_account_system(tsk); > } > EXPORT_SYMBOL_GPL(vtime_account); > #endif /* __ARCH_HAS_VTIME_ACCOUNT */ > @@ -587,3 +602,72 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime > cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st); > } > #endif
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