On 08.01.20 15:40, Michal Hocko wrote: > On Mon 30-12-19 12:38:28, Kirill A. Shutemov wrote: >> memmap_init_zone() can be called on the ranges with holes during the >> boot. It will skip any non-valid PFNs one-by-one. It works fine as long >> as holes are not too big. >> >> But huge holes in the memory map causes a problem. It takes over 20 >> seconds to walk 32TiB hole. x86-64 with 5-level paging allows for much >> larger holes in the memory map which would practically hang the system. >> >> Deferred struct page init doesn't help here. It only works on the >> present ranges. >> >> Skipping non-present sections would fix the issue. > > Makes sense to me. > >> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > > That pfn inc back and forth is quite ugly TBH but whatever. Indeed, can we please rewrite the loop to fix that? -- Thanks, David / dhildenb
