On Wed, Jan 12, 2022 at 12:31:10PM +0100, David Hildenbrand wrote: > > > > > Looking at stuff like this, I can't help but think that a: > > > > #define PageOffline PageUnaccepted > > > > and some other renaming would be a fine idea. I get that the Offline > > bit can be reused, but I'm not sure that the "Offline" *naming* should > > be reused. What you're doing here is logically distinct from existing > > offlining. > > Yes, or using a new pagetype bit to make the distinction clearer. > Especially the function names like maybe_set_page_offline() et. Al are > confusing IMHO. They are all about accepting unaccepted memory ... and > should express that. "Unaccepted" is UEFI treminology and I'm not sure we want to expose core-mm to it. Power/S390/ARM may have a different name for the same concept. Offline/online is neutral terminology, familiar to MM developers. What if I change accept->online in function names and document the meaning properly? > I assume PageOffline() will be set only on the first sub-page of a > high-order PageBuddy() page, correct? > > Then we'll have to monitor all PageOffline() users such that they can > actually deal with PageBuddy() pages spanning *multiple* base pages for > a PageBuddy() page. For now it's clear that if a page is PageOffline(), > it cannot be PageBuddy() and cannot span more than one base page. > E.g., fs/proc/kcore.c:read_kcore() assumes that PageOffline() is set on > individual base pages. Right, pages that offline from hotplug POV are never on page allocator's free lists, so it cannot ever step on them. -- Kirill A. Shutemov
