On Thu, 18 Jul 2019, Vlastimil Babka wrote: > On 7/18/19 11:44 PM, Andrew Morton wrote: > > On Wed, 19 Jun 2019 09:28:42 -0700 Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> wrote: > > > >>> Sorry for replying rather late, and not in the v2 thread, but unlike > >>> Hugh I'm not convinced that we should include vma size/alignment in the > >>> test for reporting THPeligible, which was supposed to reflect > >>> administrative settings and madvise hints. I guess it's mostly a matter > >>> of personal feeling. But one objective distinction is that the admin > >>> settings and madvise do have an exact binary result for the whole VMA, > >>> while this check is more fuzzy - only part of the VMA's span might be > >>> properly sized+aligned, and THPeligible will be 1 for the whole VMA. > >> > >> I think THPeligible is used to tell us if the vma is suitable for > >> allocating THP. Both anonymous and shmem THP checks vma size/alignment > >> to decide to or not to allocate THP. > >> > >> And, if vma size/alignment is not checked, THPeligible may show "true" > >> for even 4K mapping. This doesn't make too much sense either. > > > > This discussion seems rather inconclusive. I'll merge up the patchset > > anyway. Vlastimil, if you think some changes are needed here then > > please let's get them sorted out over the next few weeks? > > Well, Hugh did ack it, albeit without commenting on this part. I don't > feel strongly enough about this for a nack. Right, I had no further comment: Yang and I agreed one way round, you thought the other way. I was more persuaded by Yang's 4kB example than by what you wrote; but not hugely excited either way. Hugh
