Re: [PATCH 11/12] pid: rewrite task helper functions avoiding task->pid and task->tgid
Hi Richard,
Sorry, I already forgot the context, not sure I understand your email
correctly.
On 12/16, Richard Guy Briggs wrote:
On 13/08/26, Richard Guy Briggs wrote:
> On Thu, Aug 22, 2013 at 09:08:48PM +0200, Oleg Nesterov wrote:
> > On 08/20, Richard Guy Briggs wrote:
> > >
> > > static inline int is_global_init(struct task_struct *tsk)
> > > {
> > > - return tsk->pid == 1;
> > > + return task_pid_nr(tsk) == 1;
> > > }
> >
> > Probably it would be better to simply kill it. Almost every usage is
> > wrong.
>
> Can you be more clear? I don't follow. It should instead return a
> boolean. Usage of is_global_init() or task_pid_nr()?
>
> If is_global_init(), is that because they could be unaware of pid
> namespaces?
>
> If task_pid_nr(), is that for the same reason?
Oleg, I still don't understand your comment above. Kill what,
"is_global_init()"? If so, how is almost every usage of it wrong?
Because is_global_init() is only true for the main thread of /sbin/init.
Just look at oom_unkillable_task(). It tries to not kill init. But, say,
select_bad_process() can happily find a sub-thread of is_global_init()
and still kill it.
There are a number of functions that call is_global_init(). Might
any
of them be called from inside the namespace context of a container and
hence should return true?
Not sure I understand, but certainly some callers should check ->child_reaper
or SIGNAL_UNKILLABLE instead. Say, unhandled_signal().
> > > static inline bool is_idle_task(const struct
task_struct *p)
> > > {
> > > - return p->pid == 0;
> > > + return task_pid(p) == &init_struct_pid;
> > > }
> >
> > hmm. there should be a simpler check for this...
>
> Other than the original, this one is pretty simple. What did you have
> in mind?
I vaguely remember a clarification to this, but don't remember and can't
find it. What sort of simplification did you have in mind?
I do not remember ;) Most probably, I meant "it would be nice to find a
simpler check".
Oleg.