mm: remove zone_lru_lock() function, access ->lru_lock directly

We have common pattern to access lru_lock from a page pointer:
	zone_lru_lock(page_zone(page))

Which is silly, because it unfolds to this:
	&NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]->zone_pgdat->lru_lock
while we can simply do
	&NODE_DATA(page_to_nid(page))->lru_lock

Remove zone_lru_lock() function, since it's only complicate things.  Use
'page_pgdat(page)->lru_lock' pattern instead.

[aryabinin@virtuozzo.com: a slightly better version of __split_huge_page()]
  Link: http://lkml.kernel.org/r/20190301121651.7741-1-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/20190228083329.31892-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 7 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 1cc871da3fda..e054276cf397 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -775,6 +775,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
                         unsigned long end_pfn, isolate_mode_t isolate_mode)
 {
         struct zone *zone = cc->zone;
+        pg_data_t *pgdat = zone->zone_pgdat;
         unsigned long nr_scanned = 0, nr_isolated = 0;
         struct lruvec *lruvec;
         unsigned long flags = 0;
@@ -839,8 +840,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
                  * if contended.
                  */
                 if (!(low_pfn % SWAP_CLUSTER_MAX)
-                    && compact_unlock_should_abort(zone_lru_lock(zone), flags,
-                                                                &locked, cc))
+                    && compact_unlock_should_abort(&pgdat->lru_lock,
+                                            flags, &locked, cc))
                         break;
 
                 if (!pfn_valid_within(low_pfn))
@@ -910,7 +911,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
                         if (unlikely(__PageMovable(page)) &&
                                         !PageIsolated(page)) {
                                 if (locked) {
-                                        spin_unlock_irqrestore(zone_lru_lock(zone),
+                                        spin_unlock_irqrestore(&pgdat->lru_lock,
                                                                         flags);
                                         locked = false;
                                 }
@@ -940,7 +941,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
                 /* If we already hold the lock, we can skip some rechecking */
                 if (!locked) {
-                        locked = compact_lock_irqsave(zone_lru_lock(zone),
+                        locked = compact_lock_irqsave(&pgdat->lru_lock,
                                                                 &flags, cc);
 
                         /* Try get exclusive access under lock */
@@ -965,7 +966,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
                         }
                 }
 
-                lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+                lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
                 /* Try isolate the page */
                 if (__isolate_lru_page(page, isolate_mode) != 0)
@@ -1007,7 +1008,7 @@ isolate_fail:
                  */
                 if (nr_isolated) {
                         if (locked) {
-                                spin_unlock_irqrestore(zone_lru_lock(zone), flags);
+                                spin_unlock_irqrestore(&pgdat->lru_lock, flags);
                                 locked = false;
                         }
                         putback_movable_pages(&cc->migratepages);
@@ -1034,7 +1035,7 @@ isolate_fail:
 
 isolate_abort:
         if (locked)
-                spin_unlock_irqrestore(zone_lru_lock(zone), flags);
+                spin_unlock_irqrestore(&pgdat->lru_lock, flags);
 
         /*
          * Updated the cached scanner pfn once the pageblock has been scanned