[PATCH 22/25] Update NR_FREE_PAGES only as necessary

Mel Gorman
2009-04-20T22:20:16Z

When pages are being freed to the buddy allocator, the zone
NR_FREE_PAGES counter must be updated. In the case of bulk per-cpu page
freeing, it's updated once per page. This retouches cache lines more
than necessary. Update the counters one per per-cpu bulk free.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
---
mm/page_alloc.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e61867e..6bcaf08 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -460,7 +460,6 @@ static inline void __free_one_page(struct page *page,
int migratetype)
{
unsigned long page_idx;
- int order_size = 1 << order;

if (unlikely(PageCompound(page)))
if (unlikely(destroy_compound_page(page, order)))
@@ -470,10 +469,9 @@ static inline void __free_one_page(struct page *page,

page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);

- VM_BUG_ON(page_idx & (order_size - 1));
+ VM_BUG_ON(page_idx & ((1 << order) - 1));
VM_BUG_ON(bad_range(zone, page));

- __mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
while (order < MAX_ORDER-1) {
unsigned long combined_idx;
struct page *buddy;
@@ -528,6 +526,8 @@ static void free_pages_bulk(struct zone *zone, int count,
spin_lock(&zone->lock);
zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
zone->pages_scanned = 0;
+
+ __mod_zone_page_state(zone, NR_FREE_PAGES, count);
while (count--) {
struct page *page;

@@ -546,6 +546,8 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
spin_lock(&zone->lock);
zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
zone->pages_scanned = 0;
+
+ __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
__free_one_page(page, zone, order, migratetype);
spin_unlock(&zone->lock);
}
@@ -690,7 +692,6 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
list_del(&page->lru);
rmv_page_order(page);
area->nr_free--;
- __mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
expand(zone, page, order, current_order, area, migratetype);
return page;
}
@@ -830,8 +831,6 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
/* Remove the page from the freelists */
list_del(&page->lru);
rmv_page_order(page);
- __mod_zone_page_state(zone, NR_FREE_PAGES,
- -(1UL << order));

if (current_order == pageblock_order)
set_pageblock_migratetype(page,
@@ -905,6 +904,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
set_page_private(page, migratetype);
list = &page->lru;
}
+ __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
spin_unlock(&zone->lock);
return i;
}
--
1.5.6.5