1 files changed, 62 insertions, 9 deletions

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5f38c460367e..0db8037e2725 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -48,9 +48,6 @@
  * struct page (these bits with information) are always mapped into kernel
  * address space...
  *
- * PG_buddy is set to indicate that the page is free and in the buddy system
- * (see mm/page_alloc.c).
- *
  * PG_hwpoison indicates that a page got corrupted in hardware and contains
  * data with incorrect ECC bits that triggered a machine check. Accessing is
  * not safe since it may cause another machine check. Don't touch!
@@ -96,7 +93,6 @@ enum pageflags {
         PG_swapcache,           /* Swap page: swp_entry_t in private */
         PG_mappedtodisk,        /* Has blocks allocated on-disk */
         PG_reclaim,             /* To be reclaimed asap */
-        PG_buddy,               /* Page is free, on buddy lists */
         PG_swapbacked,          /* Page is backed by RAM/swap */
         PG_unevictable,         /* Page is "unevictable"  */
 #ifdef CONFIG_MMU
@@ -108,6 +104,9 @@ enum pageflags {
 #ifdef CONFIG_MEMORY_FAILURE
         PG_hwpoison,            /* hardware poisoned page. Don't touch */
 #endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        PG_compound_lock,
+#endif
         __NR_PAGEFLAGS,
 
         /* Filesystems */
@@ -198,7 +197,7 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 struct page;    /* forward declaration */
 
 TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked)
-PAGEFLAG(Error, error)
+PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
 PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
 PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
 PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
@@ -230,7 +229,6 @@ PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
  * risky: they bypass page accounting.
  */
 TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
-__PAGEFLAG(Buddy, buddy)
 PAGEFLAG(MappedToDisk, mappedtodisk)
 
 /* PG_readahead is only used for file reads; PG_reclaim is only for writes */
@@ -344,7 +342,7 @@ static inline void set_page_writeback(struct page *page)
  * tests can be used in performance sensitive paths. PageCompound is
  * generally not used in hot code paths.
  */
-__PAGEFLAG(Head, head)
+__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
 __PAGEFLAG(Tail, tail)
 
 static inline int PageCompound(struct page *page)
@@ -352,6 +350,13 @@ static inline int PageCompound(struct page *page)
         return page->flags & ((1L << PG_head) | (1L << PG_tail));
 
 }
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline void ClearPageCompound(struct page *page)
+{
+        BUG_ON(!PageHead(page));
+        ClearPageHead(page);
+}
+#endif
 #else
 /*
  * Reduce page flag use as much as possible by overlapping
@@ -389,14 +394,61 @@ static inline void __ClearPageTail(struct page *page)
         page->flags &= ~PG_head_tail_mask;
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline void ClearPageCompound(struct page *page)
+{
+        BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound));
+        clear_bit(PG_compound, &page->flags);
+}
+#endif
+
 #endif /* !PAGEFLAGS_EXTENDED */
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * PageHuge() only returns true for hugetlbfs pages, but not for
+ * normal or transparent huge pages.
+ *
+ * PageTransHuge() returns true for both transparent huge and
+ * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
+ * called only in the core VM paths where hugetlbfs pages can't exist.
+ */
+static inline int PageTransHuge(struct page *page)
+{
+        VM_BUG_ON(PageTail(page));
+        return PageHead(page);
+}
+
+static inline int PageTransCompound(struct page *page)
+{
+        return PageCompound(page);
+}
+
+#else
+
+static inline int PageTransHuge(struct page *page)
+{
+        return 0;
+}
+
+static inline int PageTransCompound(struct page *page)
+{
+        return 0;
+}
+#endif
+
 #ifdef CONFIG_MMU
 #define __PG_MLOCKED            (1 << PG_mlocked)
 #else
 #define __PG_MLOCKED            0
 #endif
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define __PG_COMPOUND_LOCK              (1 << PG_compound_lock)
+#else
+#define __PG_COMPOUND_LOCK              0
+#endif
+
 /*
  * Flags checked when a page is freed.  Pages being freed should not have
  * these flags set.  It they are, there is a problem.
@@ -404,9 +456,10 @@ static inline void __ClearPageTail(struct page *page)
 #define PAGE_FLAGS_CHECK_AT_FREE \
         (1 << PG_lru     | 1 << PG_locked    | \
          1 << PG_private | 1 << PG_private_2 | \
-         1 << PG_buddy   | 1 << PG_writeback | 1 << PG_reserved | \
+         1 << PG_writeback | 1 << PG_reserved | \
          1 << PG_slab    | 1 << PG_swapcache | 1 << PG_active | \
-         1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON)
+         1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \
+         __PG_COMPOUND_LOCK)
 
 /*
  * Flags checked when a page is prepped for return by the page allocator.