On Mon, Oct 09, 2017 at 08:14:33PM +0200, Michal Hocko wrote: > On Mon 09-10-17 13:51:47, Pavel Tatashin wrote: > > I can go back to that approach, if Michal OK with it. But, that would > > mean that I would need to touch every single architecture that > > implements vmemmap_populate(), and also pass flags at least through > > these functions on every architectures (some have more than one > > decided by configs).: > > > > vmemmap_populate() > > vmemmap_populate_basepages() > > vmemmap_populate_hugepages() > > vmemmap_pte_populate() > > __vmemmap_alloc_block_buf() > > alloc_block_buf() > > vmemmap_alloc_block() > > > > IMO, while I understand that it looks strange that we must walk page > > table after creating it, it is a better approach: more enclosed as it > > effects kasan only, and more universal as it is in common code. > > While I understand that gfp mask approach might look better at first > sight this is by no means a general purpose API so I would rather be > pragmatic and have a smaller code footprint than a more general > interface. Kasan is pretty much a special case and doing a one time > initialization 2 pass thing is imho acceptable. If this turns out to be > impractical in future then let's fix it up but right now I would rather > go a simpler path. I think the simpler path for arm64 is really to say when we want the memory zeroing as opposed to exposing pmd_large/pud_large macros. Those are likely to grow more users too, but are difficult to use correctly as we have things like contiguous ptes that map to a granule smaller than a pmd. I proposed an alternative solution to Pavel already, but it could be made less general purpose by marking the function __meminit and only having it do anything if KASAN is compiled in. Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
