From fa09303d2df4ef19b0bd5af65fa407ecacbf3b6a Mon Sep 17 00:00:00 2001
From: Christoph Lameter <clameter@schroedinger.engr.sgi.com>
Date: Wed, 25 Jul 2007 20:26:59 -0700
Subject: [PATCH] Fix up reclaim counters

Compound pages of an arbitrary order may now be on the LRU and
may be reclaimed.

Adjust the counting in vmscan.c to could the number of base
pages.

Also change the active and inactive accounting to do the same.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
---
 include/linux/mm_inline.h |   36 +++++++++++++++++++++++++++---------
 mm/vmscan.c               |   22 ++++++++++++----------
 2 files changed, 39 insertions(+), 19 deletions(-)

Index: linux-2.6/include/linux/mm_inline.h
===================================================================
--- linux-2.6.orig/include/linux/mm_inline.h	2007-08-27 19:22:13.000000000 -0700
+++ linux-2.6/include/linux/mm_inline.h	2007-08-27 21:08:27.000000000 -0700
@@ -2,39 +2,57 @@ static inline void
 add_page_to_active_list(struct zone *zone, struct page *page)
 {
 	list_add(&page->lru, &zone->active_list);
-	__inc_zone_state(zone, NR_ACTIVE);
+	if (!PageHead(page))
+		__inc_zone_state(zone, NR_ACTIVE);
+	else
+		__inc_zone_page_state(page, NR_ACTIVE);
 }
 
 static inline void
 add_page_to_inactive_list(struct zone *zone, struct page *page)
 {
 	list_add(&page->lru, &zone->inactive_list);
-	__inc_zone_state(zone, NR_INACTIVE);
+	if (!PageHead(page))
+		__inc_zone_state(zone, NR_INACTIVE);
+	else
+		__inc_zone_page_state(page, NR_INACTIVE);
 }
 
 static inline void
 del_page_from_active_list(struct zone *zone, struct page *page)
 {
 	list_del(&page->lru);
-	__dec_zone_state(zone, NR_ACTIVE);
+	if (!PageHead(page))
+		__dec_zone_state(zone, NR_ACTIVE);
+	else
+		__dec_zone_page_state(page, NR_ACTIVE);
 }
 
 static inline void
 del_page_from_inactive_list(struct zone *zone, struct page *page)
 {
 	list_del(&page->lru);
-	__dec_zone_state(zone, NR_INACTIVE);
+	if (!PageHead(page))
+		__dec_zone_state(zone, NR_INACTIVE);
+	else
+		__dec_zone_page_state(page, NR_INACTIVE);
 }
 
 static inline void
 del_page_from_lru(struct zone *zone, struct page *page)
 {
+	enum zone_stat_item counter = NR_ACTIVE;
+
 	list_del(&page->lru);
-	if (PageActive(page)) {
+	if (PageActive(page))
 		__ClearPageActive(page);
-		__dec_zone_state(zone, NR_ACTIVE);
-	} else {
-		__dec_zone_state(zone, NR_INACTIVE);
-	}
+	else
+		counter = NR_INACTIVE;
+
+	if (!PageHead(page))
+		__dec_zone_state(zone, counter);
+	else
+		__dec_zone_page_state(page, counter);
 }
 
+
Index: linux-2.6/mm/vmscan.c
===================================================================
--- linux-2.6.orig/mm/vmscan.c	2007-08-27 19:22:13.000000000 -0700
+++ linux-2.6/mm/vmscan.c	2007-08-27 21:08:27.000000000 -0700
@@ -466,14 +466,14 @@ static unsigned long shrink_page_list(st
 
 		VM_BUG_ON(PageActive(page));
 
-		sc->nr_scanned++;
+		sc->nr_scanned += compound_pages(page);
 
 		if (!sc->may_swap && page_mapped(page))
 			goto keep_locked;
 
 		/* Double the slab pressure for mapped and swapcache pages */
 		if (page_mapped(page) || PageSwapCache(page))
-			sc->nr_scanned++;
+			sc->nr_scanned += compound_pages(page);
 
 		may_enter_fs = (sc->gfp_mask & __GFP_FS) ||
 			(PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));
@@ -590,7 +590,7 @@ static unsigned long shrink_page_list(st
 
 free_it:
 		unlock_page(page);
-		nr_reclaimed++;
+		nr_reclaimed += compound_pages(page);
 		if (!pagevec_add(&freed_pvec, page))
 			__pagevec_release_nonlru(&freed_pvec);
 		continue;
@@ -682,22 +682,23 @@ static unsigned long isolate_lru_pages(u
 	unsigned long nr_taken = 0;
 	unsigned long scan;
 
-	for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
+	for (scan = 0; scan < nr_to_scan && !list_empty(src); ) {
 		struct page *page;
 		unsigned long pfn;
 		unsigned long end_pfn;
 		unsigned long page_pfn;
+		int pages;
 		int zone_id;
 
 		page = lru_to_page(src);
 		prefetchw_prev_lru_page(page, src, flags);
-
+		pages = compound_pages(page);
 		VM_BUG_ON(!PageLRU(page));
 
 		switch (__isolate_lru_page(page, mode)) {
 		case 0:
 			list_move(&page->lru, dst);
-			nr_taken++;
+			nr_taken += pages;
 			break;
 
 		case -EBUSY:
@@ -743,8 +744,8 @@ static unsigned long isolate_lru_pages(u
 			switch (__isolate_lru_page(cursor_page, mode)) {
 			case 0:
 				list_move(&cursor_page->lru, dst);
-				nr_taken++;
-				scan++;
+				nr_taken += compound_pages(cursor_page);
+				scan += compound_pages(cursor_page);
 				break;
 
 			case -EBUSY:
@@ -754,6 +755,7 @@ static unsigned long isolate_lru_pages(u
 				break;
 			}
 		}
+		scan += pages;
 	}
 
 	*scanned = scan;
@@ -1010,7 +1012,7 @@ force_reclaim_mapped:
 		ClearPageActive(page);
 
 		list_move(&page->lru, &zone->inactive_list);
-		pgmoved++;
+		pgmoved += compound_pages(page);
 		if (!pagevec_add(&pvec, page)) {
 			__mod_zone_page_state(zone, NR_INACTIVE, pgmoved);
 			spin_unlock_irq(&zone->lru_lock);
@@ -1038,7 +1040,7 @@ force_reclaim_mapped:
 		SetPageLRU(page);
 		VM_BUG_ON(!PageActive(page));
 		list_move(&page->lru, &zone->active_list);
-		pgmoved++;
+		pgmoved += compound_pages(page);
 		if (!pagevec_add(&pvec, page)) {
 			__mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
 			pgmoved = 0;