mm/vmsan: fix some typos in comment

There are some typos, fix them.

s/regsitration/registration
s/santity/sanity
s/decremeting/decrementing
Signed-off-by: Ethon Paul <ethp@qq.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200411071544.16222-1-ethp@qq.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -682,7 +682,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
 		freed += ret;
 		/*
 		 * Bail out if someone want to register a new shrinker to
-		 * prevent the regsitration from being stalled for long periods
+		 * prevent the registration from being stalled for long periods
 		 * by parallel ongoing shrinking.
 		 */
 		if (rwsem_is_contended(&shrinker_rwsem)) {
@@ -1613,7 +1613,7 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode)
 
 /*
  * Update LRU sizes after isolating pages. The LRU size updates must
- * be complete before mem_cgroup_update_lru_size due to a santity check.
+ * be complete before mem_cgroup_update_lru_size due to a sanity check.
  */
 static __always_inline void update_lru_sizes(struct lruvec *lruvec,
 			enum lru_list lru, unsigned long *nr_zone_taken)
@@ -2371,7 +2371,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 
 			/*
 			 * Minimally target SWAP_CLUSTER_MAX pages to keep
-			 * reclaim moving forwards, avoiding decremeting
+			 * reclaim moving forwards, avoiding decrementing
 			 * sc->priority further than desirable.
 			 */
 			scan = max(scan, SWAP_CLUSTER_MAX);