zsmalloc: rename class stat mutators

A cosmetic change.

o Rename class_stat_inc() and class_stat_dec() to class_stat_add()
  and class_stat_sub() correspondingly. inc/dec are usually associated
  with +1/-1 modifications, while zsmlloc can modify stats by up
  to ->objs_per_zspage. Use add/sub (follow atomics naming).

o Rename zs_stat_get() to class_stat_read()
  get() is usually associated with ref-counting and is paired with put().
  zs_stat_get() simply reads class stat so rename to reflect it.
  (This also follows atomics naming).

Link: https://lkml.kernel.org/r/20240701031140.3756345-1-senozhatsky@chromium.orgSigned-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/zsmalloc.c

@@ -512,19 +512,19 @@ static int get_size_class_index(int size)
 	return min_t(int, ZS_SIZE_CLASSES - 1, idx);
 }
 
-static inline void class_stat_inc(struct size_class *class,
-				int type, unsigned long cnt)
+static inline void class_stat_add(struct size_class *class, int type,
+				  unsigned long cnt)
 {
 	class->stats.objs[type] += cnt;
 }
 
-static inline void class_stat_dec(struct size_class *class,
-				int type, unsigned long cnt)
+static inline void class_stat_sub(struct size_class *class, int type,
+				  unsigned long cnt)
 {
 	class->stats.objs[type] -= cnt;
 }
 
-static inline unsigned long zs_stat_get(struct size_class *class, int type)
+static inline unsigned long class_stat_read(struct size_class *class, int type)
 {
 	return class->stats.objs[type];
 }
@@ -576,12 +576,12 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
 
 		seq_printf(s, " %5u %5u ", i, class->size);
 		for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++) {
-			inuse_totals[fg] += zs_stat_get(class, fg);
-			seq_printf(s, "%9lu ", zs_stat_get(class, fg));
+			inuse_totals[fg] += class_stat_read(class, fg);
+			seq_printf(s, "%9lu ", class_stat_read(class, fg));
 		}
 
-		obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
-		obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
+		obj_allocated = class_stat_read(class, ZS_OBJS_ALLOCATED);
+		obj_used = class_stat_read(class, ZS_OBJS_INUSE);
 		freeable = zs_can_compact(class);
 		spin_unlock(&class->lock);
 
@@ -686,7 +686,7 @@ static void insert_zspage(struct size_class *class,
 				struct zspage *zspage,
 				int fullness)
 {
-	class_stat_inc(class, fullness, 1);
+	class_stat_add(class, fullness, 1);
 	list_add(&zspage->list, &class->fullness_list[fullness]);
 	zspage->fullness = fullness;
 }
@@ -702,7 +702,7 @@ static void remove_zspage(struct size_class *class, struct zspage *zspage)
 	VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
 
 	list_del_init(&zspage->list);
-	class_stat_dec(class, fullness, 1);
+	class_stat_sub(class, fullness, 1);
 }
 
 /*
@@ -858,7 +858,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
 
 	cache_free_zspage(pool, zspage);
 
-	class_stat_dec(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
+	class_stat_sub(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
 	atomic_long_sub(class->pages_per_zspage, &pool->pages_allocated);
 }
 
@@ -1374,7 +1374,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
 		obj_malloc(pool, zspage, handle);
 		/* Now move the zspage to another fullness group, if required */
 		fix_fullness_group(class, zspage);
-		class_stat_inc(class, ZS_OBJS_INUSE, 1);
+		class_stat_add(class, ZS_OBJS_INUSE, 1);
 
 		goto out;
 	}
@@ -1392,8 +1392,8 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
 	newfg = get_fullness_group(class, zspage);
 	insert_zspage(class, zspage, newfg);
 	atomic_long_add(class->pages_per_zspage, &pool->pages_allocated);
-	class_stat_inc(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
-	class_stat_inc(class, ZS_OBJS_INUSE, 1);
+	class_stat_add(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
+	class_stat_add(class, ZS_OBJS_INUSE, 1);
 
 	/* We completely set up zspage so mark them as movable */
 	SetZsPageMovable(pool, zspage);
@@ -1454,7 +1454,7 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
 	spin_lock(&class->lock);
 	read_unlock(&pool->migrate_lock);
 
-	class_stat_dec(class, ZS_OBJS_INUSE, 1);
+	class_stat_sub(class, ZS_OBJS_INUSE, 1);
 	obj_free(class->size, obj);
 
 	fullness = fix_fullness_group(class, zspage);
@@ -1880,7 +1880,7 @@ static void async_free_zspage(struct work_struct *work)
 
 		class = zspage_class(pool, zspage);
 		spin_lock(&class->lock);
-		class_stat_dec(class, ZS_INUSE_RATIO_0, 1);
+		class_stat_sub(class, ZS_INUSE_RATIO_0, 1);
 		__free_zspage(pool, class, zspage);
 		spin_unlock(&class->lock);
 	}
@@ -1923,8 +1923,8 @@ static inline void zs_flush_migration(struct zs_pool *pool) { }
 static unsigned long zs_can_compact(struct size_class *class)
 {
 	unsigned long obj_wasted;
-	unsigned long obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
-	unsigned long obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
+	unsigned long obj_allocated = class_stat_read(class, ZS_OBJS_ALLOCATED);
+	unsigned long obj_used = class_stat_read(class, ZS_OBJS_INUSE);
 
 	if (obj_allocated <= obj_used)
 		return 0;