On 01.07.19 12:27, Michal Hocko wrote:

On Mon 01-07-19 11:36:44, Oscar Salvador wrote:

quoted

On Mon, Jul 01, 2019 at 10:51:44AM +0200, Michal Hocko wrote:

quoted

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?

Of course, we can also just use mem_blk->nid and rest assured that it
will never be called for memory blocks belonging to multiple nodes.

-- 

Thanks,

David / dhildenb