mm: migrate: move_pages() supports thp migration

This patch enables thp migration for move_pages(2).

Link: http://lkml.kernel.org/r/20170717193955.20207-10-zi.yan@sent.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 32 insertions, 13 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index bf5366a2176b..1088cef6ef8b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -185,8 +185,8 @@ void putback_movable_pages(struct list_head *l)
                         unlock_page(page);
                         put_page(page);
                 } else {
-                        dec_node_page_state(page, NR_ISOLATED_ANON +
-                                        page_is_file_cache(page));
+                        mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
+                                        page_is_file_cache(page), -hpage_nr_pages(page));
                         putback_lru_page(page);
                 }
         }
@@ -1146,8 +1146,8 @@ out:
                  * as __PageMovable
                  */
                 if (likely(!__PageMovable(page)))
-                        dec_node_page_state(page, NR_ISOLATED_ANON +
-                                        page_is_file_cache(page));
+                        mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
+                                        page_is_file_cache(page), -hpage_nr_pages(page));
         }
 
         /*
@@ -1421,7 +1421,17 @@ 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);
 }
@@ -1448,6 +1458,8 @@ 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;
+                struct page *head;
+                unsigned int follflags;
 
                 err = -EFAULT;
                 vma = find_vma(mm, pp->addr);
@@ -1455,8 +1467,10 @@ 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_DUMP;
+                if (!thp_migration_supported())
+                        follflags |= FOLL_SPLIT;
+                page = follow_page(vma, pp->addr, follflags);
 
                 err = PTR_ERR(page);
                 if (IS_ERR(page))
@@ -1466,7 +1480,6 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
                 if (!page)
                         goto set_status;
 
-                pp->page = page;
                 err = page_to_nid(page);
 
                 if (err == pp->node)
@@ -1481,16 +1494,22 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
                         goto put_and_set;
 
                 if (PageHuge(page)) {
-                        if (PageHead(page))
+                        if (PageHead(page)) {
                                 isolate_huge_page(page, &pagelist);
+                                err = 0;
+                                pp->page = page;
+                        }
                         goto put_and_set;
                 }
 
-                err = isolate_lru_page(page);
+                pp->page = compound_head(page);
+                head = compound_head(page);
+                err = isolate_lru_page(head);
                 if (!err) {
-                        list_add_tail(&page->lru, &pagelist);
-                        inc_node_page_state(page, NR_ISOLATED_ANON +
-                                            page_is_file_cache(page));
+                        list_add_tail(&head->lru, &pagelist);
+                        mod_node_page_state(page_pgdat(head),
+                                NR_ISOLATED_ANON + page_is_file_cache(head),
+                                hpage_nr_pages(head));
                 }
 put_and_set:
                 /*