This patch enables thp migration for mbind(2) and migrate_pages(2).

Signed-off-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
---
 mm/mempolicy.c | 94 ++++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 72 insertions(+), 22 deletions(-)

diff --git v4.5-rc5-mmotm-2016-02-24-16-18/mm/mempolicy.c 
v4.5-rc5-mmotm-2016-02-24-16-18_patched/mm/mempolicy.c
index 840a0ad..a9754dd 100644
--- v4.5-rc5-mmotm-2016-02-24-16-18/mm/mempolicy.c
+++ v4.5-rc5-mmotm-2016-02-24-16-18_patched/mm/mempolicy.c
@@ -94,6 +94,7 @@
 #include <linux/mm_inline.h>
 #include <linux/mmu_notifier.h>
 #include <linux/printk.h>
+#include <linux/swapops.h>
 
 #include <asm/tlbflush.h>
 #include <asm/uaccess.h>
@@ -487,6 +488,49 @@ static inline bool queue_pages_node_check(struct page 
*page,
        return node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT);
 }
 
+static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
+                               unsigned long end, struct mm_walk *walk)
+{
+       int ret = 0;
+       struct page *page;
+       struct queue_pages *qp = walk->private;
+       unsigned long flags;
+
+       if (unlikely(is_pmd_migration_entry(*pmd))) {
+               ret = 1;
+               goto unlock;
+       }
+       page = pmd_page(*pmd);
+       if (is_huge_zero_page(page)) {
+               spin_unlock(ptl);
+               split_huge_pmd(walk->vma, pmd, addr);
+               goto out;
+       }
+       if ((end - addr != HPAGE_PMD_SIZE) || !thp_migration_supported()) {
+               get_page(page);
+               spin_unlock(ptl);
+               lock_page(page);
+               ret = split_huge_page(page);
+               unlock_page(page);
+               put_page(page);
+               goto out;
+       }
+       if (queue_pages_node_check(page, qp)) {
+               ret = 1;
+               goto unlock;
+       }
+
+       ret = 1;
+       flags = qp->flags;
+       /* go to thp migration */
+       if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+               migrate_page_add(page, qp->pagelist, flags);
+unlock:
+       spin_unlock(ptl);
+out:
+       return ret;
+}
+
 /*
  * Scan through pages checking if pages follow certain conditions,
  * and move them to the pagelist if they do.
@@ -498,32 +542,19 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned 
long addr,
        struct page *page;
        struct queue_pages *qp = walk->private;
        unsigned long flags = qp->flags;
-       int nid, ret;
+       int ret;
        pte_t *pte;
        spinlock_t *ptl;
 
-       if (pmd_trans_huge(*pmd)) {
-               ptl = pmd_lock(walk->mm, pmd);
-               if (pmd_trans_huge(*pmd)) {
-                       page = pmd_page(*pmd);
-                       if (is_huge_zero_page(page)) {
-                               spin_unlock(ptl);
-                               split_huge_pmd(vma, pmd, addr);
-                       } else {
-                               get_page(page);
-                               spin_unlock(ptl);
-                               lock_page(page);
-                               ret = split_huge_page(page);
-                               unlock_page(page);
-                               put_page(page);
-                               if (ret)
-                                       return 0;
-                       }
-               } else {
-                       spin_unlock(ptl);
-               }
+       ptl = pmd_trans_huge_lock(pmd, vma);
+       if (ptl) {
+               ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
+               if (ret)
+                       return 0;
        }
 
+       if (pmd_trans_unstable(pmd))
+               return 0;
 retry:
        pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
        for (; addr != end; pte++, addr += PAGE_SIZE) {
@@ -980,7 +1011,17 @@ static struct page *new_node_page(struct page *page, 
unsigned long node, int **x
        if (PageHuge(page))
                return alloc_huge_page_node(page_hstate(compound_head(page)),
                                        node);
-       else
+       else if (thp_migration_supported() && PageTransHuge(page)) {
+               struct page *thp;
+
+               thp = alloc_pages_node(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(node, GFP_HIGHUSER_MOVABLE |
                                                    __GFP_THISNODE, 0);
 }
@@ -1146,6 +1187,15 @@ static struct page *new_page(struct page *page, unsigned 
long start, int **x)
        if (PageHuge(page)) {
                BUG_ON(!vma);
                return alloc_huge_page_noerr(vma, address, 1);
+       } else if (thp_migration_supported() && PageTransHuge(page)) {
+               struct page *thp;
+
+               thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
+                                        HPAGE_PMD_ORDER);
+               if (!thp)
+                       return NULL;
+               prep_transhuge_page(thp);
+               return thp;
        }
        /*
         * if !vma, alloc_page_vma() will use task or system default policy
-- 
2.7.0

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