[PATCH 11/11] Use pageblock flags for anti-fragmentation

[Mel Gorman <mel@csn.ul.ie>]

This patch alters anti-fragmentation to use the pageblock bits for tracking
the reclaimability of a block of pages.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---

 include/linux/pageblock-flags.h |    4 ++++
 mm/page_alloc.c                 |   22 ++++++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc4-mm1-102_remove_antifrag_pageflags/include/linux/pageblock-flags.h linux-2.6.19-rc4-mm1-103_antifrag_pageblock_bits/include/linux/pageblock-flags.h
--- linux-2.6.19-rc4-mm1-102_remove_antifrag_pageflags/include/linux/pageblock-flags.h	2006-10-31 17:42:25.000000000 +0000
+++ linux-2.6.19-rc4-mm1-103_antifrag_pageblock_bits/include/linux/pageblock-flags.h	2006-10-31 18:25:54.000000000 +0000
@@ -27,6 +27,10 @@
 
 /* Bit indices that affect a whole block of pages */
 enum pageblock_bits {
+#ifdef CONFIG_PAGEALLOC_ANTIFRAG
+	PB_rclmtype,
+	PB_rclmtype_end = (PB_rclmtype + 2) - 1, /* 2 bits for rclm types */
+#endif
 	NR_PAGEBLOCK_BITS
 };
 
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc4-mm1-102_remove_antifrag_pageflags/mm/page_alloc.c linux-2.6.19-rc4-mm1-103_antifrag_pageblock_bits/mm/page_alloc.c
--- linux-2.6.19-rc4-mm1-102_remove_antifrag_pageflags/mm/page_alloc.c	2006-10-31 17:44:48.000000000 +0000
+++ linux-2.6.19-rc4-mm1-103_antifrag_pageblock_bits/mm/page_alloc.c	2006-10-31 18:24:48.000000000 +0000
@@ -140,8 +140,15 @@ static unsigned long __initdata dma_rese
 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
 
 #ifdef CONFIG_PAGEALLOC_ANTIFRAG
-static inline int get_page_rclmtype(struct page *page)
+static inline int get_pageblock_rclmtype(struct page *page)
 {
+	return get_pageblock_flags_group(page, PB_rclmtype, PB_rclmtype_end);
+}
+
+static void set_pageblock_rclmtype(struct page *page, int rclmtype)
+{
+	set_pageblock_flags_group(page, (unsigned long)rclmtype,
+						PB_rclmtype, PB_rclmtype_end);
 }
 
 static inline int gfpflags_to_rclmtype(gfp_t gfp_flags)
@@ -153,11 +161,13 @@ static inline int gfpflags_to_rclmtype(g
 		((gfp_flags & __GFP_KERNRCLM) != 0);
 }
 #else
-static inline int get_page_rclmtype(struct page *page)
+static inline int get_pageblock_rclmtype(struct page *page)
 {
 	return RCLM_NORCLM;
 }
 
+static inline void set_pageblock_rclmtype(struct page *page, int rclmtype) {}
+
 static inline int gfpflags_to_rclmtype(gfp_t gfp_flags)
 {
 	return RCLM_NORCLM;
@@ -433,7 +443,7 @@ static inline void __free_one_page(struc
 {
 	unsigned long page_idx;
 	int order_size = 1 << order;
-	int rclmtype = get_page_rclmtype(page);
+	int rclmtype = get_pageblock_rclmtype(page);
 
 	if (unlikely(PageCompound(page)))
 		destroy_compound_page(page, order);
@@ -713,6 +723,7 @@ int move_freepages_block(struct zone *zo
 	if (page_zone(page) != page_zone(end_page))
 		return 0;
 
+	set_pageblock_rclmtype(start_page, rclmtype);
 	return move_freepages(zone, start_page, end_page, rclmtype);
 }
 
@@ -825,6 +836,10 @@ static struct page *__rmqueue(struct zon
 			split_count[rclmtype]++;
 
 		expand(zone, page, order, current_order, area, rclmtype);
+
+		if (current_order == MAX_ORDER - 1)
+			set_pageblock_rclmtype(page, rclmtype);
+
 		goto got_page;
 	}
 
@@ -1003,7 +1018,7 @@ void drain_all_local_pages(void) {}
 static void fastcall free_hot_cold_page(struct page *page, int cold)
 {
 	struct zone *zone = page_zone(page);
-	int pindex = get_page_rclmtype(page);
+	int pindex = get_pageblock_rclmtype(page);
 	struct per_cpu_pages *pcp;
 	unsigned long flags;
 

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