Merge branch 'akpm-current/current'

[karo-tx-linux.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a7b4e310bf42524338ee2504d21843cdd0abeab9..d594d89365ed4db7745c56fcb11b83c61bbd2c8e 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -414,15 +414,45 @@ static inline int page_count(struct page *page)
        return atomic_read(&compound_head(page)->_count);
 }
 
+#ifdef CONFIG_HUGETLB_PAGE
+extern int PageHeadHuge(struct page *page_head);
+#else /* CONFIG_HUGETLB_PAGE */
+static inline int PageHeadHuge(struct page *page_head)
+{
+       return 0;
+}
+#endif /* CONFIG_HUGETLB_PAGE */
+
+static inline bool __compound_tail_refcounted(struct page *page)
+{
+       return !PageSlab(page) && !PageHeadHuge(page);
+}
+
+/*
+ * This takes a head page as parameter and tells if the
+ * tail page reference counting can be skipped.
+ *
+ * For this to be safe, PageSlab and PageHeadHuge must remain true on
+ * any given page where they return true here, until all tail pins
+ * have been released.
+ */
+static inline bool compound_tail_refcounted(struct page *page)
+{
+       VM_BUG_ON(!PageHead(page));
+       return __compound_tail_refcounted(page);
+}
+
 static inline void get_huge_page_tail(struct page *page)
 {
        /*
         * __split_huge_page_refcount() cannot run
         * from under us.
+        * In turn no need of compound_trans_head here.
         */
        VM_BUG_ON(page_mapcount(page) < 0);
        VM_BUG_ON(atomic_read(&page->_count) != 0);
-       atomic_inc(&page->_mapcount);
+       if (compound_tail_refcounted(compound_head(page)))
+               atomic_inc(&page->_mapcount);
 }
 
 extern bool __get_page_tail(struct page *page);
@@ -1318,6 +1348,7 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
 
 #if USE_SPLIT_PTE_PTLOCKS
 #if BLOATED_SPINLOCKS
+void __init ptlock_cache_init(void);
 extern bool ptlock_alloc(struct page *page);
 extern void ptlock_free(struct page *page);
 
@@ -1326,6 +1357,7 @@ static inline spinlock_t *ptlock_ptr(struct page *page)
        return page->ptl;
 }
 #else /* BLOATED_SPINLOCKS */
+static inline void ptlock_cache_init(void) {}
 static inline bool ptlock_alloc(struct page *page)
 {
        return true;
@@ -1378,10 +1410,17 @@ static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
 {
        return &mm->page_table_lock;
 }
+static inline void ptlock_cache_init(void) {}
 static inline bool ptlock_init(struct page *page) { return true; }
 static inline void pte_lock_deinit(struct page *page) {}
 #endif /* USE_SPLIT_PTE_PTLOCKS */
 
+static inline void pgtable_init(void)
+{
+       ptlock_cache_init();
+       pgtable_cache_init();
+}
+
 static inline bool pgtable_page_ctor(struct page *page)
 {
        inc_zone_page_state(page, NR_PAGETABLE);