hugetlb, rmap: add reverse mapping for hugepage

[pandora-kernel.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 54d42b0..aa3c517 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -18,6 +18,7 @@
 #include <linux/bootmem.h>
 #include <linux/sysfs.h>
 #include <linux/slab.h>
+#include <linux/rmap.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -220,6 +221,12 @@ static pgoff_t vma_hugecache_offset(struct hstate *h,
                        (vma->vm_pgoff >> huge_page_order(h));
 }
 
+pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
+                                    unsigned long address)
+{
+       return vma_hugecache_offset(hstate_vma(vma), vma, address);
+}
+
 /*
  * Return the size of the pages allocated when backing a VMA. In the majority
  * cases this will be same size as used by the page table entries.
@@ -552,6 +559,7 @@ static void free_huge_page(struct page *page)
        set_page_private(page, 0);
        page->mapping = NULL;
        BUG_ON(page_count(page));
+       BUG_ON(page_mapcount(page));
        INIT_LIST_HEAD(&page->lru);
 
        spin_lock(&hugetlb_lock);
@@ -2129,6 +2137,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
                        entry = huge_ptep_get(src_pte);
                        ptepage = pte_page(entry);
                        get_page(ptepage);
+                       page_dup_rmap(ptepage);
                        set_huge_pte_at(dst, addr, dst_pte, entry);
                }
                spin_unlock(&src->page_table_lock);
@@ -2207,6 +2216,7 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
        flush_tlb_range(vma, start, end);
        mmu_notifier_invalidate_range_end(mm, start, end);
        list_for_each_entry_safe(page, tmp, &page_list, lru) {
+               page_remove_rmap(page);
                list_del(&page->lru);
                put_page(page);
        }
@@ -2272,6 +2282,9 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
        return 1;
 }
 
+/*
+ * Hugetlb_cow() should be called with page lock of the original hugepage held.
+ */
 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
                        unsigned long address, pte_t *ptep, pte_t pte,
                        struct page *pagecache_page)
@@ -2286,8 +2299,11 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 retry_avoidcopy:
        /* If no-one else is actually using this page, avoid the copy
         * and just make the page writable */
-       avoidcopy = (page_count(old_page) == 1);
+       avoidcopy = (page_mapcount(old_page) == 1);
        if (avoidcopy) {
+               if (!trylock_page(old_page))
+                       if (PageAnon(old_page))
+                               page_move_anon_rmap(old_page, vma, address);
                set_huge_ptep_writable(vma, address, ptep);
                return 0;
        }
@@ -2338,6 +2354,13 @@ retry_avoidcopy:
                return -PTR_ERR(new_page);
        }
 
+       /*
+        * When the original hugepage is shared one, it does not have
+        * anon_vma prepared.
+        */
+       if (unlikely(anon_vma_prepare(vma)))
+               return VM_FAULT_OOM;
+
        copy_huge_page(new_page, old_page, address, vma);
        __SetPageUptodate(new_page);
 
@@ -2352,6 +2375,8 @@ retry_avoidcopy:
                huge_ptep_clear_flush(vma, address, ptep);
                set_huge_pte_at(mm, address, ptep,
                                make_huge_pte(vma, new_page, 1));
+               page_remove_rmap(old_page);
+               hugepage_add_anon_rmap(new_page, vma, address);
                /* Make the old page be freed below */
                new_page = old_page;
        }
@@ -2452,10 +2477,17 @@ retry:
                        spin_lock(&inode->i_lock);
                        inode->i_blocks += blocks_per_huge_page(h);
                        spin_unlock(&inode->i_lock);
+                       page_dup_rmap(page);
                } else {
                        lock_page(page);
-                       page->mapping = HUGETLB_POISON;
+                       if (unlikely(anon_vma_prepare(vma))) {
+                               ret = VM_FAULT_OOM;
+                               goto backout_unlocked;
+                       }
+                       hugepage_add_new_anon_rmap(page, vma, address);
                }
+       } else {
+               page_dup_rmap(page);
        }
 
        /*
@@ -2507,6 +2539,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
        pte_t *ptep;
        pte_t entry;
        int ret;
+       struct page *page = NULL;
        struct page *pagecache_page = NULL;
        static DEFINE_MUTEX(hugetlb_instantiation_mutex);
        struct hstate *h = hstate_vma(vma);
@@ -2548,6 +2581,11 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                                                                vma, address);
        }
 
+       if (!pagecache_page) {
+               page = pte_page(entry);
+               lock_page(page);
+       }
+
        spin_lock(&mm->page_table_lock);
        /* Check for a racing update before calling hugetlb_cow */
        if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
@@ -2573,6 +2611,8 @@ out_page_table_lock:
        if (pagecache_page) {
                unlock_page(pagecache_page);
                put_page(pagecache_page);
+       } else {
+               unlock_page(page);
        }
 
 out_mutex: