mm, vmscan: remove highmem_file_pages

With the reintroduction of per-zone LRU stats, highmem_file_pages is
redundant so remove it.

[mgorman@techsingularity.net: wrong stat is being accumulated in highmem_dirtyable_memory]
  Link: http://lkml.kernel.org/r/20160725092324.GM10438@techsingularity.netLink: http://lkml.kernel.org/r/1469110261-7365-3-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 8 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 573d138fa7a5..7b5920a3500f 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -299,17 +299,13 @@ static unsigned long node_dirtyable_memory(struct pglist_data *pgdat)
 
         return nr_pages;
 }
-#ifdef CONFIG_HIGHMEM
-atomic_t highmem_file_pages;
-#endif
 
 static unsigned long highmem_dirtyable_memory(unsigned long total)
 {
 #ifdef CONFIG_HIGHMEM
         int node;
-        unsigned long x;
+        unsigned long x = 0;
         int i;
-        unsigned long dirtyable = 0;
 
         for_each_node_state(node, N_HIGH_MEMORY) {
                 for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
@@ -326,12 +322,12 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
                         nr_pages = zone_page_state(z, NR_FREE_PAGES);
                         /* watch for underflows */
                         nr_pages -= min(nr_pages, high_wmark_pages(z));
-                        dirtyable += nr_pages;
+                        nr_pages += zone_page_state(z, NR_ZONE_INACTIVE_FILE);
+                        nr_pages += zone_page_state(z, NR_ZONE_ACTIVE_FILE);
+                        x += nr_pages;
                 }
         }
 
-        x = dirtyable + atomic_read(&highmem_file_pages);
-
         /*
          * Unreclaimable memory (kernel memory or anonymous memory
          * without swap) can bring down the dirtyable pages below