On Wed 14-08-19 16:28:21, David Hildenbrand wrote: > On 14.08.19 16:17, David Hildenbrand wrote: > > On 14.08.19 16:08, Michal Hocko wrote: > >> On Fri 09-08-19 14:56:59, David Hildenbrand wrote: > >>> Take care of nr_pages not being a power of two and start not being > >>> properly aligned. Essentially, what walk_system_ram_range() could provide > >>> to us. get_order() will round-up in case it's not a power of two. > >>> > >>> This should only apply to memory blocks that contain strange memory > >>> resources (especially with holes), not to ordinary DIMMs. > >> > >> I would really like to see an example of such setup before making the > >> code hard to read. Because I am not really sure something like that > >> exists at all. > > > > I don't have a real-live example at hand (founds this while exploring > > the code), however, the linked commit changed it without stating why it > > would be safe to do so. > > So, while I agree that "not a power of two" is rare, are you sure we > will only have holes that are aligned to 4MB (especially on x86)? No I am not saying that because I do not know. I am not aware of any such HW but that doesn't really mean anything. But I would like to see an example and have it archived in the changelog before we make the code more complicated. -- Michal Hocko SUSE Labs
