linux-kernel - [PATCH 6/7] mm: page_alloc: Only account batch allocations requests that are eligible

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Date:	Fri, 13 Dec 2013 14:10:06 +0000
From:	Mel Gorman <mgorman@...e.de>
To:	Johannes Weiner <hannes@...xchg.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Dave Hansen <dave.hansen@...el.com>,
	Rik van Riel <riel@...hat.com>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>, Mel Gorman <mgorman@...e.de>
Subject: [PATCH 6/7] mm: page_alloc: Only account batch allocations requests that are eligible

Not signed off. Johannes, was the intent really to decrement the batch
counts regardless of whether the policy was being enforced or not?

---
 mm/page_alloc.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c2a2229..bf49918 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1547,7 +1547,6 @@ again:
 					  get_pageblock_migratetype(page));
 	}
 
-	__mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
 	__count_zone_vm_events(PGALLOC, zone, 1 << order);
 	zone_statistics(preferred_zone, zone, gfp_flags);
 	local_irq_restore(flags);
@@ -1923,7 +1922,8 @@ int sysctl_zone_distribute_mode_handler(ctl_table *table, int write,
  * other zones.
  */
 static bool zone_distribute_age(gfp_t gfp_mask, struct zone *preferred_zone,
-				struct zone *zone, int alloc_flags)
+				struct zone *zone, int alloc_flags,
+				bool *distrib_eligible)
 {
 	bool zone_is_local;
 	bool is_file, is_slab, is_anon;
@@ -1977,6 +1977,8 @@ static bool zone_distribute_age(gfp_t gfp_mask, struct zone *preferred_zone,
 	return true;
 
 check_batch:
+	*distrib_eligible = true;
+
 	/* Distribute to the next zone if this zone has exhausted its batch */
 	if (zone_page_state(zone, NR_ALLOC_BATCH) <= 0)
 		return true;
@@ -2000,6 +2002,7 @@ get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
 	nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
 	int zlc_active = 0;		/* set if using zonelist_cache */
 	int did_zlc_setup = 0;		/* just call zlc_setup() one time */
+	bool distrib_eligible = false;
 
 	classzone_idx = zone_idx(preferred_zone);
 zonelist_scan:
@@ -2023,7 +2026,7 @@ zonelist_scan:
 
 		/* Distribute pages to ensure fair page aging */
 		if (zone_distribute_age(gfp_mask, preferred_zone, zone,
-					alloc_flags))
+				alloc_flags, &distrib_eligible))
 			continue;
 
 		/*
@@ -2119,8 +2122,11 @@ zonelist_scan:
 try_this_zone:
 		page = buffered_rmqueue(preferred_zone, zone, order,
 						gfp_mask, migratetype);
-		if (page)
+		if (page) {
+			if (distrib_eligible)
+				__mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
 			break;
+		}
 this_zone_full:
 		if (IS_ENABLED(CONFIG_NUMA))
 			zlc_mark_zone_full(zonelist, z);
-- 
1.8.4

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