mm, vmscan: Do not wait for page writeback for GFP_NOFS allocations

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index de73c9d144e1c7b66efebb91130e65b08771eed4..d9bc87ca062bf8caaaa7c5a0be44cbef2c0e0a5d 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2328,6 +2328,31 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma,
                update_mmu_cache(vma, address, ptep);
 }
 
+static int is_hugetlb_entry_migration(pte_t pte)
+{
+       swp_entry_t swp;
+
+       if (huge_pte_none(pte) || pte_present(pte))
+               return 0;
+       swp = pte_to_swp_entry(pte);
+       if (non_swap_entry(swp) && is_migration_entry(swp))
+               return 1;
+       else
+               return 0;
+}
+
+static int is_hugetlb_entry_hwpoisoned(pte_t pte)
+{
+       swp_entry_t swp;
+
+       if (huge_pte_none(pte) || pte_present(pte))
+               return 0;
+       swp = pte_to_swp_entry(pte);
+       if (non_swap_entry(swp) && is_hwpoison_entry(swp))
+               return 1;
+       else
+               return 0;
+}
 
 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
                            struct vm_area_struct *vma)
@@ -2355,7 +2380,24 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 
                spin_lock(&dst->page_table_lock);
                spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
-               if (!huge_pte_none(huge_ptep_get(src_pte))) {
+               entry = huge_ptep_get(src_pte);
+               if (huge_pte_none(entry)) { /* skip none entry */
+                       ;
+               } else if (unlikely(is_hugetlb_entry_migration(entry) ||
+                                   is_hugetlb_entry_hwpoisoned(entry))) {
+                       swp_entry_t swp_entry = pte_to_swp_entry(entry);
+
+                       if (is_write_migration_entry(swp_entry) && cow) {
+                               /*
+                                * COW mappings require pages in both
+                                * parent and child to be set to read.
+                                */
+                               make_migration_entry_read(&swp_entry);
+                               entry = swp_entry_to_pte(swp_entry);
+                               set_huge_pte_at(src, addr, src_pte, entry);
+                       }
+                       set_huge_pte_at(dst, addr, dst_pte, entry);
+               } else {
                        if (cow)
                                huge_ptep_set_wrprotect(src, addr, src_pte);
                        entry = huge_ptep_get(src_pte);
@@ -2373,32 +2415,6 @@ nomem:
        return -ENOMEM;
 }
 
-static int is_hugetlb_entry_migration(pte_t pte)
-{
-       swp_entry_t swp;
-
-       if (huge_pte_none(pte) || pte_present(pte))
-               return 0;
-       swp = pte_to_swp_entry(pte);
-       if (non_swap_entry(swp) && is_migration_entry(swp))
-               return 1;
-       else
-               return 0;
-}
-
-static int is_hugetlb_entry_hwpoisoned(pte_t pte)
-{
-       swp_entry_t swp;
-
-       if (huge_pte_none(pte) || pte_present(pte))
-               return 0;
-       swp = pte_to_swp_entry(pte);
-       if (non_swap_entry(swp) && is_hwpoison_entry(swp))
-               return 1;
-       else
-               return 0;
-}
-
 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
                            unsigned long start, unsigned long end,
                            struct page *ref_page)
@@ -2435,9 +2451,10 @@ again:
                        continue;
 
                /*
-                * HWPoisoned hugepage is already unmapped and dropped reference
+                * Migrating hugepage or HWPoisoned hugepage is already
+                * unmapped and its refcount is dropped, so just clear pte here.
                 */
-               if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
+               if (unlikely(!pte_present(pte))) {
                        huge_pte_clear(mm, address, ptep);
                        continue;
                }