Re: [PATCH v3 10/11] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail

[Michal Hocko]

On Mon 15-07-19 13:10:33, David Hildenbrand wrote:
> On 01.07.19 12:27, Michal Hocko wrote:
> > On Mon 01-07-19 11:36:44, Oscar Salvador wrote:
> >> On Mon, Jul 01, 2019 at 10:51:44AM +0200, Michal Hocko wrote:
> >>> Yeah, we do not allow to offline multi zone (node) ranges so the current
> >>> code seems to be over engineered.
> >>>
> >>> Anyway, I am wondering why do we have to strictly check for already
> >>> removed nodes links. Is the sysfs code going to complain we we try to
> >>> remove again?
> >>
> >> No, sysfs will silently "fail" if the symlink has already been removed.
> >> At least that is what I saw last time I played with it.
> >>
> >> I guess the question is what if sysfs handling changes in the future
> >> and starts dropping warnings when trying to remove a symlink is not there.
> >> Maybe that is unlikely to happen?
> > 
> > And maybe we handle it then rather than have a static allocation that
> > everybody with hotremove configured has to pay for.
> > 
> 
> So what's the suggestion? Dropping the nodemask_t completely and calling
> sysfs_remove_link() on already potentially removed links?

Yes. In a follow up patch.
-- 
Michal Hocko
SUSE Labs