Re: [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap

From: Oscar Salvador
Date: Thu Sep 27 2018 - 08:25:42 EST


On Thu, Sep 27, 2018 at 01:09:26PM +0200, Michal Hocko wrote:
> > So there were a few things I wasn't sure we could pull outside of the
> > hotplug lock. One specific example is the bits related to resizing the pgdat
> > and zone. I wanted to avoid pulling those bits outside of the hotplug lock.
>
> Why would that be a problem. There are dedicated locks for resizing.

True is that move_pfn_range_to_zone() manages the locks for pgdat/zone resizing,
but it also takes care of calling init_currently_empty_zone() in case the zone is empty.
Could not that be a problem if we take move_pfn_range_to_zone() out of the lock?

--
Oscar Salvador
SUSE L3