patch-2_6_7-vs1_9_1_12

[linux-2.6.git] / include / linux / rmap.h

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 5f9b35f..e314834 100644 (file)
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -2,41 +2,108 @@
 #define _LINUX_RMAP_H
 /*
  * Declarations for Reverse Mapping functions in mm/rmap.c
- * Its structures are declared within that file.
  */
 
 #include <linux/config.h>
-#include <linux/linkage.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
 
-#define rmap_lock(page) \
+#define page_map_lock(page) \
        bit_spin_lock(PG_maplock, (unsigned long *)&(page)->flags)
-#define rmap_unlock(page) \
+#define page_map_unlock(page) \
        bit_spin_unlock(PG_maplock, (unsigned long *)&(page)->flags)
 
+/*
+ * The anon_vma heads a list of private "related" vmas, to scan if
+ * an anonymous page pointing to this anon_vma needs to be unmapped:
+ * the vmas on the list will be related by forking, or by splitting.
+ *
+ * Since vmas come and go as they are split and merged (particularly
+ * in mprotect), the mapping field of an anonymous page cannot point
+ * directly to a vma: instead it points to an anon_vma, on whose list
+ * the related vmas can be easily linked or unlinked.
+ *
+ * After unlinking the last vma on the list, we must garbage collect
+ * the anon_vma object itself: we're guaranteed no page can be
+ * pointing to this anon_vma once its vma list is empty.
+ */
+struct anon_vma {
+       spinlock_t lock;        /* Serialize access to vma list */
+       struct list_head head;  /* List of private "related" vmas */
+};
+
 #ifdef CONFIG_MMU
 
-struct pte_chain;
-struct pte_chain *pte_chain_alloc(int gfp_flags);
-void __pte_chain_free(struct pte_chain *pte_chain);
+extern kmem_cache_t *anon_vma_cachep;
+
+static inline struct anon_vma *anon_vma_alloc(void)
+{
+       return kmem_cache_alloc(anon_vma_cachep, SLAB_KERNEL);
+}
+
+static inline void anon_vma_free(struct anon_vma *anon_vma)
+{
+       kmem_cache_free(anon_vma_cachep, anon_vma);
+}
+
+static inline void anon_vma_lock(struct vm_area_struct *vma)
+{
+       struct anon_vma *anon_vma = vma->anon_vma;
+       if (anon_vma)
+               spin_lock(&anon_vma->lock);
+}
 
-static inline void pte_chain_free(struct pte_chain *pte_chain)
+static inline void anon_vma_unlock(struct vm_area_struct *vma)
 {
-       if (pte_chain)
-               __pte_chain_free(pte_chain);
+       struct anon_vma *anon_vma = vma->anon_vma;
+       if (anon_vma)
+               spin_unlock(&anon_vma->lock);
 }
 
-struct pte_chain * fastcall
-       page_add_rmap(struct page *, pte_t *, struct pte_chain *);
-void fastcall page_remove_rmap(struct page *, pte_t *);
+/*
+ * anon_vma helper functions.
+ */
+void anon_vma_init(void);      /* create anon_vma_cachep */
+int  anon_vma_prepare(struct vm_area_struct *);
+void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
+void anon_vma_unlink(struct vm_area_struct *);
+void anon_vma_link(struct vm_area_struct *);
+void __anon_vma_link(struct vm_area_struct *);
+
+/*
+ * rmap interfaces called when adding or removing pte of page
+ */
+void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
+void page_add_file_rmap(struct page *);
+void page_remove_rmap(struct page *);
+
+/**
+ * page_dup_rmap - duplicate pte mapping to a page
+ * @page:      the page to add the mapping to
+ *
+ * For copy_page_range only: minimal extract from page_add_rmap,
+ * avoiding unnecessary tests (already checked) so it's quicker.
+ */
+static inline void page_dup_rmap(struct page *page)
+{
+       page_map_lock(page);
+       page->mapcount++;
+       page_map_unlock(page);
+}
 
 /*
  * Called from mm/vmscan.c to handle paging out
  */
-int fastcall page_referenced(struct page *);
-int fastcall try_to_unmap(struct page *);
+int page_referenced(struct page *);
+int try_to_unmap(struct page *);
 
 #else  /* !CONFIG_MMU */
 
+#define anon_vma_init()                do {} while (0)
+#define anon_vma_prepare(vma)  (0)
+#define anon_vma_link(vma)     do {} while (0)
+
 #define page_referenced(page)  TestClearPageReferenced(page)
 #define try_to_unmap(page)     SWAP_FAIL