mm: move most file-based accounting to the node

There are now a number of accounting oddities such as mapped file pages
being accounted for on the node while the total number of file pages are
accounted on the zone.  This can be coped with to some extent but it's
confusing so this patch moves the relevant file-based accounted.  Due to
throttling logic in the page allocator for reliable OOM detection, it is
still necessary to track dirty and writeback pages on a per-zone basis.

[mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting]
  Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index f7c0fb9..f97591d 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -498,20 +498,12 @@
  */
 bool node_dirty_ok(struct pglist_data *pgdat)
 {
-	int z;
 	unsigned long limit = node_dirty_limit(pgdat);
 	unsigned long nr_pages = 0;
 
-	for (z = 0; z < MAX_NR_ZONES; z++) {
-		struct zone *zone = pgdat->node_zones + z;
-
-		if (!populated_zone(zone))
-			continue;
-
-		nr_pages += zone_page_state(zone, NR_FILE_DIRTY);
-		nr_pages += zone_page_state(zone, NR_UNSTABLE_NFS);
-		nr_pages += zone_page_state(zone, NR_WRITEBACK);
-	}
+	nr_pages += node_page_state(pgdat, NR_FILE_DIRTY);
+	nr_pages += node_page_state(pgdat, NR_UNSTABLE_NFS);
+	nr_pages += node_page_state(pgdat, NR_WRITEBACK);
 
 	return nr_pages <= limit;
 }
@@ -1601,10 +1593,10 @@
 		 * written to the server's write cache, but has not yet
 		 * been flushed to permanent storage.
 		 */
-		nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
-					global_page_state(NR_UNSTABLE_NFS);
+		nr_reclaimable = global_node_page_state(NR_FILE_DIRTY) +
+					global_node_page_state(NR_UNSTABLE_NFS);
 		gdtc->avail = global_dirtyable_memory();
-		gdtc->dirty = nr_reclaimable + global_page_state(NR_WRITEBACK);
+		gdtc->dirty = nr_reclaimable + global_node_page_state(NR_WRITEBACK);
 
 		domain_dirty_limits(gdtc);
 
@@ -1941,8 +1933,8 @@
 	 * as we're trying to decide whether to put more under writeback.
 	 */
 	gdtc->avail = global_dirtyable_memory();
-	gdtc->dirty = global_page_state(NR_FILE_DIRTY) +
-		      global_page_state(NR_UNSTABLE_NFS);
+	gdtc->dirty = global_node_page_state(NR_FILE_DIRTY) +
+		      global_node_page_state(NR_UNSTABLE_NFS);
 	domain_dirty_limits(gdtc);
 
 	if (gdtc->dirty > gdtc->bg_thresh)
@@ -1986,8 +1978,8 @@
                  */
                 dirty_thresh += dirty_thresh / 10;      /* wheeee... */
 
-                if (global_page_state(NR_UNSTABLE_NFS) +
-			global_page_state(NR_WRITEBACK) <= dirty_thresh)
+                if (global_node_page_state(NR_UNSTABLE_NFS) +
+			global_node_page_state(NR_WRITEBACK) <= dirty_thresh)
                         	break;
                 congestion_wait(BLK_RW_ASYNC, HZ/10);
 
@@ -2015,8 +2007,8 @@
 void laptop_mode_timer_fn(unsigned long data)
 {
 	struct request_queue *q = (struct request_queue *)data;
-	int nr_pages = global_page_state(NR_FILE_DIRTY) +
-		global_page_state(NR_UNSTABLE_NFS);
+	int nr_pages = global_node_page_state(NR_FILE_DIRTY) +
+		global_node_page_state(NR_UNSTABLE_NFS);
 	struct bdi_writeback *wb;
 
 	/*
@@ -2467,7 +2459,8 @@
 		wb = inode_to_wb(inode);
 
 		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_DIRTY);
-		__inc_zone_page_state(page, NR_FILE_DIRTY);
+		__inc_node_page_state(page, NR_FILE_DIRTY);
+		__inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 		__inc_zone_page_state(page, NR_DIRTIED);
 		__inc_wb_stat(wb, WB_RECLAIMABLE);
 		__inc_wb_stat(wb, WB_DIRTIED);
@@ -2488,7 +2481,8 @@
 {
 	if (mapping_cap_account_dirty(mapping)) {
 		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
-		dec_zone_page_state(page, NR_FILE_DIRTY);
+		dec_node_page_state(page, NR_FILE_DIRTY);
+		dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 		dec_wb_stat(wb, WB_RECLAIMABLE);
 		task_io_account_cancelled_write(PAGE_SIZE);
 	}
@@ -2744,7 +2738,8 @@
 		wb = unlocked_inode_to_wb_begin(inode, &locked);
 		if (TestClearPageDirty(page)) {
 			mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
-			dec_zone_page_state(page, NR_FILE_DIRTY);
+			dec_node_page_state(page, NR_FILE_DIRTY);
+			dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 			dec_wb_stat(wb, WB_RECLAIMABLE);
 			ret = 1;
 		}
@@ -2790,7 +2785,8 @@
 	}
 	if (ret) {
 		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
-		dec_zone_page_state(page, NR_WRITEBACK);
+		dec_node_page_state(page, NR_WRITEBACK);
+		dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 		inc_zone_page_state(page, NR_WRITTEN);
 	}
 	unlock_page_memcg(page);
@@ -2844,7 +2840,8 @@
 	}
 	if (!ret) {
 		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
-		inc_zone_page_state(page, NR_WRITEBACK);
+		inc_node_page_state(page, NR_WRITEBACK);
+		inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 	}
 	unlock_page_memcg(page);
 	return ret;