From: Zi Yan <zi....@cs.rutgers.edu> In [1], Andrea reported that during memory hotplug/hot remove prep_transhuge_page() is called incorrectly on non-THP pages for migration, when THP is on but THP migration is not enabled. This leads to a bad state of target pages for migration.
This patch fixes it by only calling prep_transhuge_page() when we are certain that the target page is THP. [1] https://lkml.org/lkml/2017/11/20/411 Cc: sta...@vger.kernel.org # v4.14 Fixes: 8135d8926c08 ("mm: memory_hotplug: memory hotremove supports thp migration") Reported-by: Andrea Reale <a...@linux.vnet.ibm.com> Signed-off-by: Zi Yan <zi....@cs.rutgers.edu> Cc: Naoya Horiguchi <n-horigu...@ah.jp.nec.com> Cc: "Jérôme Glisse" <jgli...@redhat.com> --- include/linux/migrate.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 895ec0c4942e..a2246cf670ba 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -54,7 +54,7 @@ static inline struct page *new_page_nodemask(struct page *page, new_page = __alloc_pages_nodemask(gfp_mask, order, preferred_nid, nodemask); - if (new_page && PageTransHuge(page)) + if (new_page && PageTransHuge(new_page)) prep_transhuge_page(new_page); return new_page; -- 2.14.2
