On Fri 22-05-15 18:29:00, Oleg Nesterov wrote:
> On 05/22, Michal Hocko wrote:
> >
> > On Thu 21-05-15 21:27:16, Oleg Nesterov wrote:
> > > On 05/20, Michal Hocko wrote:
> > > >
> > > > On Wed 20-05-15 19:53:02, Oleg Nesterov wrote:
> > > > >
> > > > > Yes, yes, the group leader can't go away until the whole thread-group dies.
> > > >
> > > > OK, then we should have a guarantee that mm->owner is always thread
> > > > group leader, right?
> > >
> > > No, please note that the exiting leader does exit_mm()->mm_update_next_owner()
> > > and this changes mm->owner.
> >
> > I am confused now. Yeah it changes the owner but the new one will be
> > again the thread group leader, right?
>
> Why?
>
> In the likely case (if CLONE_VM without CLONE_THREAD was not used) the
> last for_each_process() in mm_update_next_owner() will find another thread
> from the same group.
My understanding was that for_each_process will iterate only over
processes (represented by the thread group leaders). That was the reason
I was asking about thread group leader exiting before other threads.
I am sorry to ask again, but let me ask again. How would we get
!group_leader from p->{real_parent->}sibling or from for_each_process?
> Oh. I think mm_update_next_owner() needs some cleanups. Perhaps I'll send
> the patch today.
Please hold on, I have a patch to get rid of the owner altogether. I
will post it sometimes next week. Let's see whether this is a viable
option. If not then we can clean this up.
Thanks!
--
Michal Hocko
SUSE Labs
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>