Messages in this thread | | | From | Gerrit Huizenga <> | Subject | Re: [patch 02/38] CKRM e18: Processor Delay Accounting | Date | Thu, 23 Jun 2005 13:44:49 -0700 |
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On Thu, 23 Jun 2005 11:37:32 +0200, Ingo Molnar wrote: > > * Ingo Molnar <mingo@elte.hu> wrote: > > > > > * Gerrit Huizenga <gh@us.ibm.com> wrote: > > > > > +#ifdef CONFIG_DELAY_ACCT > > > +int task_running_sys(struct task_struct *p) > > > +{ > > > + return task_is_running(p); > > > +} > > > +EXPORT_SYMBOL_GPL(task_running_sys); > > > +#endif > > > > why is this function defined, and why is it exported?
This was exported so it could be used in the classification engine which is a loadable module which determines how and when tasks join classes. There are two classification engines - a basic one (RBCE) and a more advanced one (CRBCE). The latter allows a user to set some basic rules on how newly created tasks will join a class.
> this: > > +#define task_is_running(p) (this_rq() == task_rq(p)) > > is totally bogus. What you are checking is not whether 'the task is > running', but it is a complex way of doing p->thread_info->cpu == > smp_processor_id(). This, combined with: > > + if (pdata == NULL) > + /* some wierdo race condition .. simply ignore */ > + continue; > + if (thread->state == TASK_RUNNING) { > + if (task_running_sys(thread)) { > + atomic_inc((atomic_t *) & > + (PSAMPLE(pdata)->cpu_running)); > + run++; > + } else { > + atomic_inc((atomic_t *) & > + (PSAMPLE(pdata)->cpu_waiting)); > + wait++; > + } > + } > > yields completely incorrect code, and bogus data. If your goal is to > sample executing-on-cpu vs. on-runqueue-waiting-to-run states then you > should use the already existing task_curr(p) call. > > Ingo
I'll clean this up later this afternoon and regen a patch.
thanks!
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