mm: mempolicy: mbind and migrate_pages support thp migration

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

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>

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8e89aa8ea7d6c7ff128a671e3fdf9ed4127517c6..0fa665dabd43c6ac9f3c072954cd65aba3afc48e 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -97,6 +97,7 @@
 #include <linux/mm_inline.h>
 #include <linux/mmu_notifier.h>
 #include <linux/printk.h>
+#include <linux/swapops.h>
 
 #include <asm/tlbflush.h>
 #include <linux/uaccess.h>
@@ -426,6 +427,49 @@ static inline bool queue_pages_required(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, false, NULL);
+               goto out;
+       }
+       if (!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_required(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.
@@ -437,30 +481,15 @@ 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, false, NULL);
-                       } 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))
@@ -481,7 +510,7 @@ retry:
                        continue;
                if (!queue_pages_required(page, qp))
                        continue;
-               if (PageTransCompound(page)) {
+               if (PageTransCompound(page) && !thp_migration_supported()) {
                        get_page(page);
                        pte_unmap_unlock(pte, ptl);
                        lock_page(page);
@@ -893,19 +922,21 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 
 #ifdef CONFIG_MIGRATION
 /*
- * page migration
+ * page migration, thp tail pages can be passed.
  */
 static void migrate_page_add(struct page *page, struct list_head *pagelist,
                                unsigned long flags)
 {
+       struct page *head = compound_head(page);
        /*
         * Avoid migrating a page that is shared with others.
         */
-       if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
-               if (!isolate_lru_page(page)) {
-                       list_add_tail(&page->lru, pagelist);
-                       inc_node_page_state(page, NR_ISOLATED_ANON +
-                                           page_is_file_cache(page));
+       if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(head) == 1) {
+               if (!isolate_lru_page(head)) {
+                       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));
                }
        }
 }
@@ -915,7 +946,17 @@ 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),
+                       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);
 }
@@ -1081,6 +1122,15 @@ 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