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authorAndrew Morton <akpm@osdl.org>2006-01-08 01:04:36 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:14:04 -0800
commit349aef0bc4c7f07d685c977e12d0e2d0b5d0e6db (patch)
tree6bb266ed8826bb4e7355a07a0092acb3d5d92647
parent59d9136b9844d3a0376d93c945ab280decedb323 (diff)
[PATCH] shrink struct page
Reduce the size of the pageframe for NR_CPUS>4, CONFIG_PREEMPT back to the minimal size by unionising both ->private and ->mapping with the pagetable lock. It uses an anonymous struct and hence requires gcc-3.x. Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/mm.h41
1 files changed, 22 insertions, 19 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7ff54242c5d..df80e63903b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -223,24 +223,27 @@ struct page {
* & limit reverse map searches.
*/
union {
- unsigned long private; /* Mapping-private opaque data:
- * usually used for buffer_heads
- * if PagePrivate set; used for
- * swp_entry_t if PageSwapCache
- * When page is free, this indicates
- * order in the buddy system.
- */
+ struct {
+ unsigned long private; /* Mapping-private opaque data:
+ * usually used for buffer_heads
+ * if PagePrivate set; used for
+ * swp_entry_t if PageSwapCache.
+ * When page is free, this
+ * indicates order in the buddy
+ * system.
+ */
+ struct address_space *mapping; /* If low bit clear, points to
+ * inode address_space, or NULL.
+ * If page mapped as anonymous
+ * memory, low bit is set, and
+ * it points to anon_vma object:
+ * see PAGE_MAPPING_ANON below.
+ */
+ };
#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
- spinlock_t ptl;
+ spinlock_t ptl;
#endif
- } u;
- struct address_space *mapping; /* If low bit clear, points to
- * inode address_space, or NULL.
- * If page mapped as anonymous
- * memory, low bit is set, and
- * it points to anon_vma object:
- * see PAGE_MAPPING_ANON below.
- */
+ };
pgoff_t index; /* Our offset within mapping. */
struct list_head lru; /* Pageout list, eg. active_list
* protected by zone->lru_lock !
@@ -261,8 +264,8 @@ struct page {
#endif /* WANT_PAGE_VIRTUAL */
};
-#define page_private(page) ((page)->u.private)
-#define set_page_private(page, v) ((page)->u.private = (v))
+#define page_private(page) ((page)->private)
+#define set_page_private(page, v) ((page)->private = (v))
/*
* FIXME: take this include out, include page-flags.h in
@@ -815,7 +818,7 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
* overflow into the next struct page (as it might with DEBUG_SPINLOCK).
* When freeing, reset page->mapping so free_pages_check won't complain.
*/
-#define __pte_lockptr(page) &((page)->u.ptl)
+#define __pte_lockptr(page) &((page)->ptl)
#define pte_lock_init(_page) do { \
spin_lock_init(__pte_lockptr(_page)); \
} while (0)