[PATCH 1/3] mm: Minor clean-up of page flags in mm/page_alloc.c v5

Russ Anderson
2008-05-16T19:22:45Z

Move the definition of the groups of bits to page-flags.h.

The purpose of this clean up is that the next patch will
conditionally add a page flag to the groups. Doing that
in a header file is cleaner than adding #ifdefs to the
C code.

Signed-off-by: Russ Anderson <rja@sgi.com>

---
include/linux/page-flags.h | 23 +++++++++++++++++++++++
mm/page_alloc.c | 34 +++-------------------------------
2 files changed, 26 insertions(+), 31 deletions(-)

Index: linus/mm/page_alloc.c
=================================--- linus.orig/mm/page_alloc.c 2008-05-15 12:58:58.429776893 -0500
+++ linus/mm/page_alloc.c 2008-05-16 12:25:20.494096186 -0500
@@ -237,16 +237,7 @@ static void bad_page(struct page *page)
printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
KERN_EMERG "Backtrace:\n");
dump_stack();
- page->flags &= ~(1 << PG_lru |
- 1 << PG_private |
- 1 << PG_locked |
- 1 << PG_active |
- 1 << PG_dirty |
- 1 << PG_reclaim |
- 1 << PG_slab |
- 1 << PG_swapcache |
- 1 << PG_writeback |
- 1 << PG_buddy );
+ page->flags &= ~PAGE_FLAGS_CLEAR_WHEN_BAD;
set_page_count(page, 0);
reset_page_mapcount(page);
page->mapping = NULL;
@@ -463,16 +454,7 @@ static inline int free_pages_check(struc
(page->mapping != NULL) |
(page_get_page_cgroup(page) != NULL) |
(page_count(page) != 0) |
- (page->flags & (
- 1 << PG_lru |
- 1 << PG_private |
- 1 << PG_locked |
- 1 << PG_active |
- 1 << PG_slab |
- 1 << PG_swapcache |
- 1 << PG_writeback |
- 1 << PG_reserved |
- 1 << PG_buddy ))))
+ (page->flags & PAGE_FLAGS_CHECK_AT_FREE)))
bad_page(page);
if (PageDirty(page))
__ClearPageDirty(page);
@@ -616,17 +598,7 @@ static int prep_new_page(struct page *pa
(page->mapping != NULL) |
(page_get_page_cgroup(page) != NULL) |
(page_count(page) != 0) |
- (page->flags & (
- 1 << PG_lru |
- 1 << PG_private |
- 1 << PG_locked |
- 1 << PG_active |
- 1 << PG_dirty |
- 1 << PG_slab |
- 1 << PG_swapcache |
- 1 << PG_writeback |
- 1 << PG_reserved |
- 1 << PG_buddy ))))
+ (page->flags & PAGE_FLAGS_CHECK_AT_PREP)))
bad_page(page);

/*
Index: linus/include/linux/page-flags.h
=================================--- linus.orig/include/linux/page-flags.h 2008-05-15 12:58:26.265815299 -0500
+++ linus/include/linux/page-flags.h 2008-05-16 12:25:20.494096186 -0500
@@ -306,5 +306,28 @@ static inline void __ClearPageTail(struc
}

#endif /* !PAGEFLAGS_EXTENDED */
+
+#define PAGE_FLAGS (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
+ 1 << PG_buddy | 1 << PG_writeback | \
+ 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active)
+
+/*
+ * Flags checked in bad_page(). Pages on the free list should not have
+ * these flags set. It they are, there is a problem.
+ */
+#define PAGE_FLAGS_CLEAR_WHEN_BAD (PAGE_FLAGS | 1 << PG_reclaim | 1 << PG_dirty)
+
+/*
+ * Flags checked when a page is freed. Pages being freed should not have
+ * these flags set. It they are, there is a problem.
+ */
+#define PAGE_FLAGS_CHECK_AT_FREE (PAGE_FLAGS | 1 << PG_reserved)
+
+/*
+ * Flags checked when a page is freed. Pages being freed should not have
+ * these flags set. It they are, there is a problem.
+ */
+#define PAGE_FLAGS_CHECK_AT_PREP (PAGE_FLAGS | 1 << PG_reserved | 1 << PG_dirty)
+
#endif /* !__GENERATING_BOUNDS_H */
#endif /* PAGE_FLAGS_H */