mm/vmstat: correct some wrong comments

Patch series "Cleanup for vmstat".

This series contains cleanups to remove unneeded return value, correct
wrong comment and simplify the array size calculation.  More details can
be found in the respective changelogs.

This patch (of 3):

Correct wrong fls(mem+1) to fls(mem)+1 and remove the duplicated comment
with quiet_vmstat().

Link: https://lkml.kernel.org/r/20210715122911.15700-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210715122911.15700-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmstat.c

@@ -204,7 +204,7 @@ int calculate_normal_threshold(struct zone *zone)
 	 *
 	 * Some sample thresholds:
 	 *
-	 * Threshold	Processors	(fls)	Zonesize	fls(mem+1)
+	 * Threshold	Processors	(fls)	Zonesize	fls(mem)+1
 	 * ------------------------------------------------------------------
 	 * 8		1		1	0.9-1 GB	4
 	 * 16		2		2	0.9-1 GB	4
@@ -1875,11 +1875,6 @@ static void vmstat_update(struct work_struct *w)
 	}
 }
 
-/*
- * Switch off vmstat processing and then fold all the remaining differentials
- * until the diffs stay at zero. The function is used by NOHZ and can only be
- * invoked when tick processing is not active.
- */
 /*
  * Check if the diffs for a certain cpu indicate that
  * an update is needed.