mm: page_alloc: calculate classzone_idx once from the zonelist ref

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>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 34 insertions, 25 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 09345ab7fb63..8f785b1534a3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1916,11 +1916,10 @@ 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 */
@@ -1928,7 +1927,6 @@ get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
         bool consider_zone_dirty = (alloc_flags & ALLOC_WMARK_LOW) &&
                                 (gfp_mask & __GFP_WRITE);
 
-        classzone_idx = zone_idx(preferred_zone);
 zonelist_scan:
         /*
          * Scan zonelist, looking for a zone with enough free.
@@ -2186,7 +2184,7 @@ 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;
 
@@ -2204,7 +2202,7 @@ __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;
 
@@ -2239,7 +2237,7 @@ 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, enum migrate_mode mode,
+        int classzone_idx, int migratetype, enum migrate_mode mode,
         bool *contended_compaction, bool *deferred_compaction,
         unsigned long *did_some_progress)
 {
@@ -2267,7 +2265,7 @@ __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);
@@ -2299,7 +2297,8 @@ static inline 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, enum migrate_mode mode, bool *contended_compaction,
+        int classzone_idx, int migratetype,
+        enum migrate_mode mode, bool *contended_compaction,
         bool *deferred_compaction, unsigned long *did_some_progress)
 {
         return NULL;
@@ -2339,7 +2338,7 @@ 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;
@@ -2357,7 +2356,8 @@ 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
@@ -2380,14 +2380,14 @@ 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);
@@ -2488,7 +2488,7 @@ 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;
@@ -2537,15 +2537,18 @@ restart:
          * Find the true preferred zone if the allocation is unconstrained by
          * cpusets.
          */
-        if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
-                first_zones_zonelist(zonelist, high_zoneidx, NULL,
-                                        &preferred_zone);
+        if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
+                struct zoneref *preferred_zoneref;
+                preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
+                                NULL, &preferred_zone);
+                classzone_idx = zonelist_zone_idx(preferred_zoneref);
+        }
 
 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;
 
@@ -2560,7 +2563,7 @@ 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;
                 }
@@ -2591,7 +2594,8 @@ rebalance:
          */
         page = __alloc_pages_direct_compact(gfp_mask, order, zonelist,
                                         high_zoneidx, nodemask, alloc_flags,
-                                        preferred_zone, migratetype,
+                                        preferred_zone,
+                                        classzone_idx, migratetype,
                                         migration_mode, &contended_compaction,
                                         &deferred_compaction,
                                         &did_some_progress);
@@ -2621,7 +2625,8 @@ rebalance:
                                         zonelist, high_zoneidx,
                                         nodemask,
                                         alloc_flags, preferred_zone,
-                                        migratetype, &did_some_progress);
+                                        classzone_idx, migratetype,
+                                        &did_some_progress);
         if (page)
                 goto got_pg;
 
@@ -2640,7 +2645,7 @@ rebalance:
                         page = __alloc_pages_may_oom(gfp_mask, order,
                                         zonelist, high_zoneidx,
                                         nodemask, preferred_zone,
-                                        migratetype);
+                                        classzone_idx, migratetype);
                         if (page)
                                 goto got_pg;
 
@@ -2681,7 +2686,8 @@ rebalance:
                  */
                 page = __alloc_pages_direct_compact(gfp_mask, order, zonelist,
                                         high_zoneidx, nodemask, alloc_flags,
-                                        preferred_zone, migratetype,
+                                        preferred_zone,
+                                        classzone_idx, migratetype,
                                         migration_mode, &contended_compaction,
                                         &deferred_compaction,
                                         &did_some_progress);
@@ -2708,10 +2714,12 @@ __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;
+        int classzone_idx;
 
         gfp_mask &= gfp_allowed_mask;
 
@@ -2734,11 +2742,12 @@ 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)
@@ -2748,7 +2757,7 @@ 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
@@ -2774,7 +2783,7 @@ 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);