On Wed 24-03-21 13:23:47, David Hildenbrand wrote: > On 24.03.21 13:10, Michal Hocko wrote: > > On Wed 24-03-21 13:03:29, Michal Hocko wrote: > > > On Wed 24-03-21 11:12:59, Oscar Salvador wrote: > > [...] > > > > an additional remark > > > > > > - online_pages()->move_pfn_range_to_zone(): Accounts for node/zone's spanned pages > > > > - online_pages()->zone->present_pages += nr_pages; > > > > I am pretty sure you shouldn't account vmmemmap pages to the target zone > > in some cases - e.g. vmemmap cannot be part of the movable zone, can it? > > So this would be yet another special casing. This patch has got it wrong > > unless I have missed some special casing. > > > > It's a bit unfortunate that we have to discuss the very basic design > decisions again. It would be great to have those basic design decisions layed out in the changelog. > @Oscar, maybe you can share the links where we discussed all this and add > some of it to the patch description. > > I think what we have right here is good enough for an initial version, from > where on we can improve things without having to modify calling code. I have to say I really dislike vmemmap proliferation into {on,off}lining. It just doesn't belong there from a layering POV. All this code should care about is to hand over pages to the allocator and make them visible. Is that a sufficient concern to nack the whole thing? No, I do not think so. But I do not see any particular rush to have this work needs to be merged ASAP. -- Michal Hocko SUSE Labs