Re: linux/kernel/sched.c: context_switch().

From: fabio de francesco
Date: Wed Sep 08 2010 - 09:23:41 EST


On Wednesday 08 September 2010 15:10:49 you wrote:
> Long day? Do you mean likely(!mm) actually means unlikely(0)?

No, no. I am sorry for my poor English. I mean:"likely(!mm)" is like
"likely(0)".

> On 8 September 2010 20:08, fabio de francesco <fabio@xxxxxxxxxxx> wrote:
> > There must be something I am missing in sched.c at context_switch()
> > function definition.
> >
> > There I can read the following code:
> >
> > static inline void
> > context_switch(struct rq *rq, struct task_struct *prev,
> > struct task_struct *next)
> > {
> > ...
> > struct mm_struct *mm;
> > mm = next->mm;
> > if (likely(!mm)) {
> > next->active_mm = oldmm;
> > atomic_inc(&oldmm->mm_count);
> > enter_lazy_tlb(oldmm, next);
> > } else
> > switch_mm(oldmm, mm, next);
> > ...
> > }
> >
> > May someone please explain why the mm pointer is likely supposed to be
> > NULL?
> >
> > Thanks in advance.
> >
> > fabio
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