[PATCH 06/16] mm: page_alloc: Calculate classzone_idx once from the zonelist ref

[Mel Gorman <mgorman@suse.de>]

There is no need to calculate zone_idx(preferred_zone) multiple times
or use the pgdat to figure it out.

Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 mm/page_alloc.c | 43 ++++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3f2a9dd..88a6dac 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1893,17 +1893,15 @@ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
 static struct page *
 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
 		struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
-		struct zone *preferred_zone, int migratetype)
+		struct zone *preferred_zone, int classzone_idx, int migratetype)
 {
 	struct zoneref *z;
 	struct page *page = NULL;
-	int classzone_idx;
 	struct zone *zone;
 	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 */
 
-	classzone_idx = zone_idx(preferred_zone);
 zonelist_scan:
 	/*
 	 * Scan zonelist, looking for a zone with enough free.
@@ -2160,7 +2158,7 @@ static inline struct page *
 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 	struct zonelist *zonelist, enum zone_type high_zoneidx,
 	nodemask_t *nodemask, struct zone *preferred_zone,
-	int migratetype)
+	int classzone_idx, int migratetype)
 {
 	struct page *page;
 
@@ -2178,7 +2176,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
 		order, zonelist, high_zoneidx,
 		ALLOC_WMARK_HIGH|ALLOC_CPUSET,
-		preferred_zone, migratetype);
+		preferred_zone, classzone_idx, migratetype);
 	if (page)
 		goto out;
 
@@ -2213,7 +2211,7 @@ static struct page *
 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
 	struct zonelist *zonelist, enum zone_type high_zoneidx,
 	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
-	int migratetype, bool sync_migration,
+	int classzone_idx, int migratetype, bool sync_migration,
 	bool *contended_compaction, bool *deferred_compaction,
 	unsigned long *did_some_progress)
 {
@@ -2241,7 +2239,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
 		page = get_page_from_freelist(gfp_mask, nodemask,
 				order, zonelist, high_zoneidx,
 				alloc_flags & ~ALLOC_NO_WATERMARKS,
-				preferred_zone, migratetype);
+				preferred_zone, classzone_idx, migratetype);
 		if (page) {
 			preferred_zone->compact_blockskip_flush = false;
 			compaction_defer_reset(preferred_zone, order, true);
@@ -2314,7 +2312,7 @@ static inline struct page *
 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
 	struct zonelist *zonelist, enum zone_type high_zoneidx,
 	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
-	int migratetype, unsigned long *did_some_progress)
+	int classzone_idx, int migratetype, unsigned long *did_some_progress)
 {
 	struct page *page = NULL;
 	bool drained = false;
@@ -2332,7 +2330,8 @@ retry:
 	page = get_page_from_freelist(gfp_mask, nodemask, order,
 					zonelist, high_zoneidx,
 					alloc_flags & ~ALLOC_NO_WATERMARKS,
-					preferred_zone, migratetype);
+					preferred_zone, classzone_idx,
+					migratetype);
 
 	/*
 	 * If an allocation failed after direct reclaim, it could be because
@@ -2355,14 +2354,14 @@ static inline struct page *
 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
 	struct zonelist *zonelist, enum zone_type high_zoneidx,
 	nodemask_t *nodemask, struct zone *preferred_zone,
-	int migratetype)
+	int classzone_idx, int migratetype)
 {
 	struct page *page;
 
 	do {
 		page = get_page_from_freelist(gfp_mask, nodemask, order,
 			zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
-			preferred_zone, migratetype);
+			preferred_zone, classzone_idx, migratetype);
 
 		if (!page && gfp_mask & __GFP_NOFAIL)
 			wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
@@ -2463,7 +2462,7 @@ static inline struct page *
 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 	struct zonelist *zonelist, enum zone_type high_zoneidx,
 	nodemask_t *nodemask, struct zone *preferred_zone,
-	int migratetype)
+	int classzone_idx, int migratetype)
 {
 	const gfp_t wait = gfp_mask & __GFP_WAIT;
 	struct page *page = NULL;
@@ -2520,7 +2519,7 @@ rebalance:
 	/* This is the last chance, in general, before the goto nopage. */
 	page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
 			high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
-			preferred_zone, migratetype);
+			preferred_zone, classzone_idx, migratetype);
 	if (page)
 		goto got_pg;
 
@@ -2535,7 +2534,7 @@ rebalance:
 
 		page = __alloc_pages_high_priority(gfp_mask, order,
 				zonelist, high_zoneidx, nodemask,
-				preferred_zone, migratetype);
+				preferred_zone, classzone_idx, migratetype);
 		if (page) {
 			goto got_pg;
 		}
@@ -2568,6 +2567,7 @@ rebalance:
 					zonelist, high_zoneidx,
 					nodemask,
 					alloc_flags, preferred_zone,
+					classzone_idx,
 					migratetype, sync_migration,
 					&contended_compaction,
 					&deferred_compaction,
@@ -2591,7 +2591,8 @@ rebalance:
 					zonelist, high_zoneidx,
 					nodemask,
 					alloc_flags, preferred_zone,
-					migratetype, &did_some_progress);
+					classzone_idx, migratetype,
+					&did_some_progress);
 	if (page)
 		goto got_pg;
 
@@ -2610,7 +2611,7 @@ rebalance:
 			page = __alloc_pages_may_oom(gfp_mask, order,
 					zonelist, high_zoneidx,
 					nodemask, preferred_zone,
-					migratetype);
+					classzone_idx, migratetype);
 			if (page)
 				goto got_pg;
 
@@ -2653,6 +2654,7 @@ rebalance:
 					zonelist, high_zoneidx,
 					nodemask,
 					alloc_flags, preferred_zone,
+					classzone_idx,
 					migratetype, sync_migration,
 					&contended_compaction,
 					&deferred_compaction,
@@ -2680,11 +2682,13 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 {
 	enum zone_type high_zoneidx = gfp_zone(gfp_mask);
 	struct zone *preferred_zone;
+	struct zoneref *preferred_zoneref;
 	struct page *page = NULL;
 	int migratetype = allocflags_to_migratetype(gfp_mask);
 	unsigned int cpuset_mems_cookie;
 	int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET|ALLOC_FAIR;
 	struct mem_cgroup *memcg = NULL;
+	int classzone_idx;
 
 	gfp_mask &= gfp_allowed_mask;
 
@@ -2714,11 +2718,12 @@ retry_cpuset:
 	cpuset_mems_cookie = read_mems_allowed_begin();
 
 	/* The preferred zone is used for statistics later */
-	first_zones_zonelist(zonelist, high_zoneidx,
+	preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
 				nodemask ? : &cpuset_current_mems_allowed,
 				&preferred_zone);
 	if (!preferred_zone)
 		goto out;
+	classzone_idx = zonelist_zone_idx(preferred_zoneref);
 
 #ifdef CONFIG_CMA
 	if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
@@ -2728,7 +2733,7 @@ retry:
 	/* First allocation attempt */
 	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
 			zonelist, high_zoneidx, alloc_flags,
-			preferred_zone, migratetype);
+			preferred_zone, classzone_idx, migratetype);
 	if (unlikely(!page)) {
 		/*
 		 * The first pass makes sure allocations are spread
@@ -2754,7 +2759,7 @@ retry:
 		gfp_mask = memalloc_noio_flags(gfp_mask);
 		page = __alloc_pages_slowpath(gfp_mask, order,
 				zonelist, high_zoneidx, nodemask,
-				preferred_zone, migratetype);
+				preferred_zone, classzone_idx, migratetype);
 	}
 
 	trace_mm_page_alloc(page, order, gfp_mask, migratetype);
-- 
1.8.4.5

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