On Thu, 28 Jan 2021 06:52:21 +0100 Oscar Salvador <osalvador@xxxxxxx> wrote: > On Wed, Jan 27, 2021 at 03:36:41PM -0800, Mike Kravetz wrote: > > Yes, this patch is somewhat optional. It should be a minor improvement > > in cases where we are dealing with hpages in a non-migratable hstate. > > Although, I do not believe this is the common case. > > > > The real reason for even looking into this was a comment by Oscar. With > > the name change to HPageMigratable, it implies that the page is migratable. > > However, this is not the case if the page's hstate does not support migration. > > So, if we check the hstate when setting the flag we can eliminate those > > cases where the page is certainly not migratable. > > > > I don't really love this patch. It has minimal functional value. > > > > Oscar, what do you think about dropping this? > > Yeah, I remember this topic arose during a discussion of patch#2 in the > early versions, about whether the renaming to HPageMigratable made > sense. > > Back then I thought that we could have this in one place at fault-path [1], > which should have made this prettier, but it is not the case. > True is that the optimization is little, so I am fine with dropping this > patch. I've dropped it. > unmap_and_move_huge_page() fences off pages belonging to non-migratable > hstates. > > [1] https://patchwork.kernel.org/project/linux-mm/patch/20210120013049.311822-3-mike.kravetz@xxxxxxxxxx/#23914033
