[PATCH v1 10/11] mm: migrate: move_pages() supports thp migration

[Naoya Horiguchi]

This patch enables thp migration for move_pages(2).

Signed-off-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
---
 mm/migrate.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git v4.5-rc5-mmotm-2016-02-24-16-18/mm/migrate.c 
v4.5-rc5-mmotm-2016-02-24-16-18_patched/mm/migrate.c
index 31bc724..5653d49 100644
--- v4.5-rc5-mmotm-2016-02-24-16-18/mm/migrate.c
+++ v4.5-rc5-mmotm-2016-02-24-16-18_patched/mm/migrate.c
@@ -1240,7 +1240,17 @@ static struct page *new_page_node(struct page *p, 
unsigned long private,
        if (PageHuge(p))
                return alloc_huge_page_node(page_hstate(compound_head(p)),
                                        pm->node);
-       else
+       else if (thp_migration_supported() && PageTransHuge(p)) {
+               struct page *thp;
+
+               thp = alloc_pages_node(pm->node,
+                       (GFP_TRANSHUGE | __GFP_THISNODE) & ~__GFP_RECLAIM,
+                       HPAGE_PMD_ORDER);
+               if (!thp)
+                       return NULL;
+               prep_transhuge_page(thp);
+               return thp;
+       } else
                return __alloc_pages_node(pm->node,
                                GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, 0);
 }
@@ -1267,6 +1277,7 @@ static int do_move_page_to_node_array(struct mm_struct 
*mm,
        for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
                struct vm_area_struct *vma;
                struct page *page;
+               unsigned int follflags;
 
                err = -EFAULT;
                vma = find_vma(mm, pp->addr);
@@ -1274,8 +1285,10 @@ static int do_move_page_to_node_array(struct mm_struct 
*mm,
                        goto set_status;
 
                /* FOLL_DUMP to ignore special (like zero) pages */
-               page = follow_page(vma, pp->addr,
-                               FOLL_GET | FOLL_SPLIT | FOLL_DUMP);
+               follflags = FOLL_GET | FOLL_SPLIT | FOLL_DUMP;
+               if (thp_migration_supported())
+                       follflags &= ~FOLL_SPLIT;
+               page = follow_page(vma, pp->addr, follflags);
 
                err = PTR_ERR(page);
                if (IS_ERR(page))
@@ -1303,6 +1316,11 @@ static int do_move_page_to_node_array(struct mm_struct 
*mm,
                        if (PageHead(page))
                                isolate_huge_page(page, &pagelist);
                        goto put_and_set;
+               } else if (PageTransCompound(page)) {
+                       if (PageTail(page)) {
+                               err = pp->node;
+                               goto put_and_set;
+                       }
                }
 
                err = isolate_lru_page(page);
-- 
2.7.0