From 754078eb45df8069f389f3371002e7e24962e1a2 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 19 May 2016 17:13:33 -0700 Subject: [PATCH] mm, page_alloc: use __dec_zone_state for order-0 page allocation __dec_zone_state is cheaper to use for removing an order-0 page as it has fewer conditions to check. The performance difference on a page allocator microbenchmark is; 4.6.0-rc2 4.6.0-rc2 optiter-v1r20 decstat-v1r20 Min alloc-odr0-1 382.00 ( 0.00%) 381.00 ( 0.26%) Min alloc-odr0-2 282.00 ( 0.00%) 275.00 ( 2.48%) Min alloc-odr0-4 233.00 ( 0.00%) 229.00 ( 1.72%) Min alloc-odr0-8 203.00 ( 0.00%) 199.00 ( 1.97%) Min alloc-odr0-16 188.00 ( 0.00%) 186.00 ( 1.06%) Min alloc-odr0-32 182.00 ( 0.00%) 179.00 ( 1.65%) Min alloc-odr0-64 177.00 ( 0.00%) 174.00 ( 1.69%) Min alloc-odr0-128 175.00 ( 0.00%) 172.00 ( 1.71%) Min alloc-odr0-256 184.00 ( 0.00%) 181.00 ( 1.63%) Min alloc-odr0-512 197.00 ( 0.00%) 193.00 ( 2.03%) Min alloc-odr0-1024 203.00 ( 0.00%) 201.00 ( 0.99%) Min alloc-odr0-2048 209.00 ( 0.00%) 206.00 ( 1.44%) Min alloc-odr0-4096 214.00 ( 0.00%) 212.00 ( 0.93%) Min alloc-odr0-8192 218.00 ( 0.00%) 215.00 ( 1.38%) Min alloc-odr0-16384 219.00 ( 0.00%) 216.00 ( 1.37%) Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Jesper Dangaard Brouer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 789e5f065e8d..8f6b6eab074f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2417,6 +2417,7 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, else page = list_first_entry(list, struct page, lru); + __dec_zone_state(zone, NR_ALLOC_BATCH); list_del(&page->lru); pcp->count--; } else { @@ -2438,11 +2439,11 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, spin_unlock(&zone->lock); if (!page) goto failed; + __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order)); __mod_zone_freepage_state(zone, -(1 << order), get_pcppage_migratetype(page)); } - __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order)); if (atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]) <= 0 && !test_bit(ZONE_FAIR_DEPLETED, &zone->flags)) set_bit(ZONE_FAIR_DEPLETED, &zone->flags); -- 2.20.1