On Fri, Mar 26, 2021 at 09:52:58AM +0100, David Hildenbrand wrote: > Might have to set fully spanned section online. (vmemmap >= SECTION_SIZE) Hi David, could you elaborate on this a bit? > Something else to note: > > > We'll not call the memory notifier (e.g., MEM_ONLINE) for the vmemmap. The > result is that > > 1. We won't allocate extended struct pages for the range. Don't think this > is really problematic (pages are never allocated/freed, so I guess we don't > care - like ZONE_DEVICE code). > > 2. We won't allocate kasan shadow memory. We most probably have to do it > explicitly via kasan_add_zero_shadow()/kasan_remove_zero_shadow(), see > mm/memremap.c:pagemap_range() > > > Further a locking rework might be necessary. We hold the device hotplug > lock, but not the memory hotplug lock. E.g., for get_online_mems(). Might > have to move that out online_pages. I will have a look and see how it goes. -- Oscar Salvador SUSE L3
