mm: add NR_ZSMALLOC to vmstat

zram is very popular for some of the embedded world (e.g., TV, mobile
phones).  On those system, zsmalloc's consumed memory size is never
trivial (one of example from real product system, total memory: 800M,
zsmalloc consumed: 150M), so we have used this out of tree patch to
monitor system memory behavior via /proc/vmstat.

With zsmalloc in vmstat, it helps in tracking down system behavior due
to memory usage.

[minchan@kernel.org: zsmalloc: follow up zsmalloc vmstat]
  Link: http://lkml.kernel.org/r/20160607091737.GC23435@bbox
[akpm@linux-foundation.org: fix build with CONFIG_ZSMALLOC=m]
Link: http://lkml.kernel.org/r/1464919731-13255-1-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Chanho Min <chanho.min@lge.com>
Cc: Chan Gyun Jeong <chan.jeong@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 6b6986a02aa0..e4e8081b160b 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1007,6 +1007,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
                 next = get_next_page(page);
                 reset_page(page);
                 unlock_page(page);
+                dec_zone_page_state(page, NR_ZSPAGES);
                 put_page(page);
                 page = next;
         } while (page != NULL);
@@ -1137,11 +1138,15 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
 
                 page = alloc_page(gfp);
                 if (!page) {
-                        while (--i >= 0)
+                        while (--i >= 0) {
+                                dec_zone_page_state(pages[i], NR_ZSPAGES);
                                 __free_page(pages[i]);
+                        }
                         cache_free_zspage(pool, zspage);
                         return NULL;
                 }
+
+                inc_zone_page_state(page, NR_ZSPAGES);
                 pages[i] = page;
         }