thp: setup huge zero page on non-write page fault

[firefly-linux-kernel-4.4.55.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index 89341b658bd06b05d908f8becfef7fe0d904b808..50c5b8f3a359b611a22e1e3715dd816880e4651e 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -910,25 +910,29 @@ static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
 static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
                        struct shmem_inode_info *info, pgoff_t index)
 {
-       struct mempolicy mpol, *spol;
        struct vm_area_struct pvma;
-
-       spol = mpol_cond_copy(&mpol,
-                       mpol_shared_policy_lookup(&info->policy, index));
+       struct page *page;
 
        /* Create a pseudo vma that just contains the policy */
        pvma.vm_start = 0;
        /* Bias interleave by inode number to distribute better across nodes */
        pvma.vm_pgoff = index + info->vfs_inode.i_ino;
        pvma.vm_ops = NULL;
-       pvma.vm_policy = spol;
-       return swapin_readahead(swap, gfp, &pvma, 0);
+       pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
+
+       page = swapin_readahead(swap, gfp, &pvma, 0);
+
+       /* Drop reference taken by mpol_shared_policy_lookup() */
+       mpol_cond_put(pvma.vm_policy);
+
+       return page;
 }
 
 static struct page *shmem_alloc_page(gfp_t gfp,
                        struct shmem_inode_info *info, pgoff_t index)
 {
        struct vm_area_struct pvma;
+       struct page *page;
 
        /* Create a pseudo vma that just contains the policy */
        pvma.vm_start = 0;
@@ -937,10 +941,12 @@ static struct page *shmem_alloc_page(gfp_t gfp,
        pvma.vm_ops = NULL;
        pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
 
-       /*
-        * alloc_page_vma() will drop the shared policy reference
-        */
-       return alloc_page_vma(gfp, &pvma, 0);
+       page = alloc_page_vma(gfp, &pvma, 0);
+
+       /* Drop reference taken by mpol_shared_policy_lookup() */
+       mpol_cond_put(pvma.vm_policy);
+
+       return page;
 }
 #else /* !CONFIG_NUMA */
 #ifdef CONFIG_TMPFS