vmscan: use atomic-long for shrinker batching

[pandora-kernel.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3b3e3b8..4baadd1 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -10,6 +10,7 @@
 #include <linux/mmzone.h>
 #include <linux/rbtree.h>
 #include <linux/prio_tree.h>
+#include <linux/atomic.h>
 #include <linux/debug_locks.h>
 #include <linux/mm_types.h>
 #include <linux/range.h>
@@ -356,36 +357,50 @@ static inline struct page *compound_head(struct page *page)
        return page;
 }
 
+/*
+ * The atomic page->_mapcount, starts from -1: so that transitions
+ * both from it and to it can be tracked, using atomic_inc_and_test
+ * and atomic_add_negative(-1).
+ */
+static inline void reset_page_mapcount(struct page *page)
+{
+       atomic_set(&(page)->_mapcount, -1);
+}
+
+static inline int page_mapcount(struct page *page)
+{
+       return atomic_read(&(page)->_mapcount) + 1;
+}
+
 static inline int page_count(struct page *page)
 {
        return atomic_read(&compound_head(page)->_count);
 }
 
+static inline void get_huge_page_tail(struct page *page)
+{
+       /*
+        * __split_huge_page_refcount() cannot run
+        * from under us.
+        */
+       VM_BUG_ON(page_mapcount(page) < 0);
+       VM_BUG_ON(atomic_read(&page->_count) != 0);
+       atomic_inc(&page->_mapcount);
+}
+
+extern bool __get_page_tail(struct page *page);
+
 static inline void get_page(struct page *page)
 {
+       if (unlikely(PageTail(page)))
+               if (likely(__get_page_tail(page)))
+                       return;
        /*
         * Getting a normal page or the head of a compound page
-        * requires to already have an elevated page->_count. Only if
-        * we're getting a tail page, the elevated page->_count is
-        * required only in the head page, so for tail pages the
-        * bugcheck only verifies that the page->_count isn't
-        * negative.
+        * requires to already have an elevated page->_count.
         */
-       VM_BUG_ON(atomic_read(&page->_count) < !PageTail(page));
+       VM_BUG_ON(atomic_read(&page->_count) <= 0);
        atomic_inc(&page->_count);
-       /*
-        * Getting a tail page will elevate both the head and tail
-        * page->_count(s).
-        */
-       if (unlikely(PageTail(page))) {
-               /*
-                * This is safe only because
-                * __split_huge_page_refcount can't run under
-                * get_page().
-                */
-               VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
-               atomic_inc(&page->first_page->_count);
-       }
 }
 
 static inline struct page *virt_to_head_page(const void *x)
@@ -803,21 +818,6 @@ static inline pgoff_t page_index(struct page *page)
        return page->index;
 }
 
-/*
- * The atomic page->_mapcount, like _count, starts from -1:
- * so that transitions both from it and to it can be tracked,
- * using atomic_inc_and_test and atomic_add_negative(-1).
- */
-static inline void reset_page_mapcount(struct page *page)
-{
-       atomic_set(&(page)->_mapcount, -1);
-}
-
-static inline int page_mapcount(struct page *page)
-{
-       return atomic_read(&(page)->_mapcount) + 1;
-}
-
 /*
  * Return true if this page is mapped into pagetables.
  */