On Mon, 16 Jun 2014, Naoya Horiguchi wrote: > On Sun, Jun 15, 2014 at 05:19:29PM -0700, Hugh Dickins wrote: > > > > Hold on, that restriction of hugepage migration was marked for stable > > 3.12+, whereas this is marked for stable 2.6.36+ (a glance at my old > > trees suggests 2.6.37+, but you may know better - perhaps hugepage > > migration got backported to 2.6.36-stable, though hardly seems > > stable material). > > Sorry, I misinterpreted one thing. > I thought hugepage migration was merged at 2.6.36 because git-describe > shows v2.6.36-rc7-73-g290408d4a2 for commit 290408d4a2 "hugetlb: hugepage > migration core." But actually that's merged at commit f1ebdd60cc, or > v2.6.36-5792-gf1ebdd60cc73. So this is 2.6.37 stuff. > > Originally hugepage migration was used only for soft offlining in > mm/memory-failure.c which is available only in x86_64, so we implicitly > assumed that hugepage migration was restricted to x86_64. > At 3.12, hugepage migration became available for numa APIs like mbind(), > which are used for other architectures, so the restriction with > hugepage_migration_supported() became necessary since then. > This is the reason why the disablement was marked for 3.12+. > This patch are helpful before extension in 3.12, so it should be marked 2.6.37+. That all makes sense to me now: thanks a lot for explaining the history. Hugh -- 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>