On Wed, Sep 16, 2020 at 08:34:11PM +0200, David Hildenbrand wrote: > @@ -1523,7 +1524,13 @@ void __free_pages_core(struct page *page, unsigned int order) > > atomic_long_add(nr_pages, &page_zone(page)->managed_pages); > set_page_refcounted(page); > - __free_pages(page, order); > + > + /* > + * Bypass PCP and place fresh pages right to the tail, primarily > + * relevant for memory onlining. > + */ > + page_ref_dec(page); > + __free_pages_ok(page, order, FOP_TO_TAIL); Sorry, I must be missing something obvious here, but I am a bit confused here. I get the part of placing them at the tail so rmqueue_bulk() won't find them, but I do not get why we decrement page's refcount. IIUC, its refcount will be 0, but why do we want to do that? Another thing a bit unrelated... we mess three times with page's refcount (two before this patch). Why do we have this dance in place? Thanks -- Oscar Salvador SUSE L3
