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Subject[RFC] [PATCH 5/5] Dynamically allocated pageflags - PageBuddy conversion.
Date
Convert PageBuddy to dynamically allocate pageflags.

Again, not sure that we'd actually want to apply this, but it demonstrates
that the implementation is usable.

Signed-off-by: Nigel Cunningham <nigel@nigel.suspend2.net>

include/linux/page-flags.h | 8 ++++----
mm/dyn_pageflags.c | 2 ++
mm/page_alloc.c | 12 ++++++------
3 files changed, 12 insertions(+), 10 deletions(-)
diff -ruNp 923-page-buddy-pageflags.patch-old/include/linux/page-flags.h 923-page-buddy-pageflags.patch-new/include/linux/page-flags.h
--- 923-page-buddy-pageflags.patch-old/include/linux/page-flags.h 2007-07-23 22:13:44.000000000 +1000
+++ 923-page-buddy-pageflags.patch-new/include/linux/page-flags.h 2007-07-23 19:48:40.000000000 +1000
@@ -87,7 +87,6 @@
#define PG_swapcache 15 /* Swap page: swp_entry_t in private */

#define PG_reclaim 17 /* To be reclaimed asap */
-#define PG_buddy 19 /* Page is free, on buddy lists */

/* PG_owner_priv_1 users should have descriptive aliases */
#define PG_checked PG_owner_priv_1 /* Used by some filesystems */
@@ -213,9 +212,10 @@ extern struct dyn_pageflags dyn_Slab_map
ret; \
})

-#define PageBuddy(page) test_bit(PG_buddy, &(page)->flags)
-#define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags)
-#define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags)
+extern struct dyn_pageflags dyn_Buddy_map;
+#define PageBuddy(page) test_dynpageflag(&dyn_Buddy_map, page)
+#define __SetPageBuddy(page) set_dynpageflag(&dyn_Buddy_map, page)
+#define __ClearPageBuddy(page) clear_dynpageflag(&dyn_Buddy_map, page)

extern struct dyn_pageflags dyn_MappedToDisk_map;
#define PageMappedToDisk(page) test_dynpageflag(&dyn_MappedToDisk_map, page)
diff -ruNp 923-page-buddy-pageflags.patch-old/mm/dyn_pageflags.c 923-page-buddy-pageflags.patch-new/mm/dyn_pageflags.c
--- 923-page-buddy-pageflags.patch-old/mm/dyn_pageflags.c 2007-07-23 22:13:44.000000000 +1000
+++ 923-page-buddy-pageflags.patch-new/mm/dyn_pageflags.c 2007-07-23 22:11:10.000000000 +1000
@@ -115,6 +115,7 @@ static int dyn_pageflags_debug = 0;

DECLARE_DYN_PAGEFLAGS(dyn_MappedToDisk_map);
DECLARE_DYN_PAGEFLAGS(dyn_Slab_map);
+DECLARE_DYN_PAGEFLAGS(dyn_Buddy_map);
#ifdef CONFIG_SWAP
DECLARE_DYN_PAGEFLAGS(dyn_SwapCache_map);
#endif
@@ -246,6 +247,7 @@ void __init dyn_pageflags_init(void)

/* Allocate the slab map early and not sparse. */
BUG_ON(allocate_dyn_pageflags(&dyn_Slab_map, 0));
+ BUG_ON(allocate_dyn_pageflags(&dyn_Buddy_map, 0));
}

/**
diff -ruNp 923-page-buddy-pageflags.patch-old/mm/page_alloc.c 923-page-buddy-pageflags.patch-new/mm/page_alloc.c
--- 923-page-buddy-pageflags.patch-old/mm/page_alloc.c 2007-07-23 22:13:44.000000000 +1000
+++ 923-page-buddy-pageflags.patch-new/mm/page_alloc.c 2007-07-23 19:48:40.000000000 +1000
@@ -204,9 +204,9 @@ static void bad_page(struct page *page)
1 << PG_dirty |
1 << PG_reclaim |
1 << PG_swapcache |
- 1 << PG_writeback |
- 1 << PG_buddy );
+ 1 << PG_writeback);
__ClearPageSlab(page);
+ __ClearPageBuddy(page);
set_page_count(page, 0);
reset_page_mapcount(page);
page->mapping = NULL;
@@ -434,6 +434,7 @@ static inline int free_pages_check(struc
(page->mapping != NULL) |
(page_count(page) != 0) |
(PageSlab(page)) |
+ (PageBuddy(page)) |
(page->flags & (
1 << PG_lru |
1 << PG_private |
@@ -441,8 +442,7 @@ static inline int free_pages_check(struc
1 << PG_active |
1 << PG_swapcache |
1 << PG_writeback |
- 1 << PG_reserved |
- 1 << PG_buddy ))))
+ 1 << PG_reserved))))
bad_page(page);
/*
* PageReclaim == PageTail. It is only an error
@@ -588,6 +588,7 @@ static int prep_new_page(struct page *pa
(page->mapping != NULL) |
(page_count(page) != 0) |
(PageSlab(page)) |
+ (PageBuddy(page)) |
(page->flags & (
1 << PG_lru |
1 << PG_private |
@@ -597,8 +598,7 @@ static int prep_new_page(struct page *pa
1 << PG_reclaim |
1 << PG_swapcache |
1 << PG_writeback |
- 1 << PG_reserved |
- 1 << PG_buddy ))))
+ 1 << PG_reserved))))
bad_page(page);

/*
-
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