[PATCH] unpaged: unifdefed PageCompound

It looks like snd_xxx is not the only nopage to be using PageReserved as a way
of holding a high-order page together: which no longer works, but is masked by
our failure to free from VM_RESERVED areas.  We cannot fix that bug without
first substituting another way to hold the high-order page together, while
farming out the 0-order pages from within it.

That's just what PageCompound is designed for, but it's been kept under
CONFIG_HUGETLB_PAGE.  Remove the #ifdefs: which saves some space (out- of-line
put_page), doesn't slow down what most needs to be fast (already using
hugetlb), and unifies the way we handle high-order pages.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0986d19..9701210 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -311,8 +311,6 @@ struct page {
 
 extern void FASTCALL(__page_cache_release(struct page *));
 
-#ifdef CONFIG_HUGETLB_PAGE
-
 static inline int page_count(struct page *page)
 {
        if (PageCompound(page))
@@ -329,23 +327,6 @@ static inline void get_page(struct page *page)
 
 void put_page(struct page *page);
 
-#else          /* CONFIG_HUGETLB_PAGE */
-
-#define page_count(p)          (atomic_read(&(p)->_count) + 1)
-
-static inline void get_page(struct page *page)
-{
-       atomic_inc(&page->_count);
-}
-
-static inline void put_page(struct page *page)
-{
-       if (put_page_testzero(page))
-               __page_cache_release(page);
-}
-
-#endif         /* CONFIG_HUGETLB_PAGE */
-
 /*
  * Multiple processes may "see" the same page. E.g. for untouched
  * mappings of /dev/null, all processes see the same page full of

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index f34767c..343083f 100644 (file)
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -287,11 +287,7 @@ extern void __mod_page_state(unsigned long offset, unsigned long delta);
 #define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
 #define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
 
-#ifdef CONFIG_HUGETLB_PAGE
 #define PageCompound(page)     test_bit(PG_compound, &(page)->flags)
-#else
-#define PageCompound(page)     0
-#endif
 #define SetPageCompound(page)  set_bit(PG_compound, &(page)->flags)
 #define ClearPageCompound(page)        clear_bit(PG_compound, &(page)->flags)
 

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bd4de59..23b84c4 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -148,10 +148,6 @@ static void bad_page(const char *function, struct page *page)
        add_taint(TAINT_BAD_PAGE);
 }
 
-#ifndef CONFIG_HUGETLB_PAGE
-#define prep_compound_page(page, order) do { } while (0)
-#define destroy_compound_page(page, order) do { } while (0)
-#else
 /*
  * Higher-order pages are called "compound pages".  They are structured thusly:
  *
@@ -205,7 +201,6 @@ static void destroy_compound_page(struct page *page, unsigned long order)
                ClearPageCompound(p);
        }
 }
-#endif         /* CONFIG_HUGETLB_PAGE */
 
 /*
  * function for dealing with page's order in buddy system.

diff --git a/mm/swap.c b/mm/swap.c
index d09cf7f..73d3514 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -34,8 +34,6 @@
 /* How many pages do we try to swap or page in/out together? */
 int page_cluster;
 
-#ifdef CONFIG_HUGETLB_PAGE
-
 void put_page(struct page *page)
 {
        if (unlikely(PageCompound(page))) {
@@ -52,7 +50,6 @@ void put_page(struct page *page)
                __page_cache_release(page);
 }
 EXPORT_SYMBOL(put_page);
-#endif
 
 /*
  * Writeback is about to end against a page which has been marked for immediate