zsmalloc: show per fullness group class stats

We keep the old fullness (3/4 threshold) reporting in
zs_stats_size_show().  Switch from allmost full/empty stats to
fine-grained per inuse ratio (fullness group) reporting, which gives
signicantly more data on classes fragmentation.

Link: https://lkml.kernel.org/r/20230304034835.2082479-5-senozhatsky@chromium.orgSigned-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/zsmalloc.c

@@ -172,9 +172,7 @@
 enum fullness_group {
 	ZS_INUSE_RATIO_0,
 	ZS_INUSE_RATIO_10,
-	/* NOTE: 5 more fullness groups here */
-	ZS_INUSE_RATIO_70	= 7,
-	/* NOTE: 2 more fullness groups here */
+	/* NOTE: 8 more fullness groups here */
 	ZS_INUSE_RATIO_99       = 10,
 	ZS_INUSE_RATIO_100,
 	NR_FULLNESS_GROUPS,
@@ -621,23 +619,22 @@ static unsigned long zs_can_compact(struct size_class *class);
 
 static int zs_stats_size_show(struct seq_file *s, void *v)
 {
-	int i;
+	int i, fg;
 	struct zs_pool *pool = s->private;
 	struct size_class *class;
 	int objs_per_zspage;
-	unsigned long class_almost_full, class_almost_empty;
 	unsigned long obj_allocated, obj_used, pages_used, freeable;
-	unsigned long total_class_almost_full = 0, total_class_almost_empty = 0;
 	unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0;
 	unsigned long total_freeable = 0;
+	unsigned long inuse_totals[NR_FULLNESS_GROUPS] = {0, };
 
-	seq_printf(s, " %5s %5s %11s %12s %13s %10s %10s %16s %8s\n",
-			"class", "size", "almost_full", "almost_empty",
+	seq_printf(s, " %5s %5s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %13s %10s %10s %16s %8s\n",
+			"class", "size", "10%", "20%", "30%", "40%",
+			"50%", "60%", "70%", "80%", "90%", "99%", "100%",
 			"obj_allocated", "obj_used", "pages_used",
 			"pages_per_zspage", "freeable");
 
 	for (i = 0; i < ZS_SIZE_CLASSES; i++) {
-		int fg;
 
 		class = pool->size_class[i];
 
@@ -645,16 +642,12 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
 			continue;
 
 		spin_lock(&pool->lock);
-		class_almost_full = 0;
-		class_almost_empty = 0;
-		/*
-		 * Replicate old behaviour for almost_full and almost_empty
-		 * stats.
-		 */
-		for (fg = ZS_INUSE_RATIO_70; fg <= ZS_INUSE_RATIO_99; fg++)
-			class_almost_full += zs_stat_get(class, fg);
-		for (fg = ZS_INUSE_RATIO_10; fg < ZS_INUSE_RATIO_70; fg++)
-			class_almost_empty += zs_stat_get(class, fg);
+
+		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));
+		}
 
 		obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
 		obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
@@ -665,14 +658,10 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
 		pages_used = obj_allocated / objs_per_zspage *
 				class->pages_per_zspage;
 
-		seq_printf(s, " %5u %5u %11lu %12lu %13lu"
-				" %10lu %10lu %16d %8lu\n",
-			i, class->size, class_almost_full, class_almost_empty,
+		seq_printf(s, "%13lu %10lu %10lu %16d %8lu\n",
 			   obj_allocated, obj_used, pages_used,
 			   class->pages_per_zspage, freeable);
 
-		total_class_almost_full += class_almost_full;
-		total_class_almost_empty += class_almost_empty;
 		total_objs += obj_allocated;
 		total_used_objs += obj_used;
 		total_pages += pages_used;
@@ -680,10 +669,14 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
 	}
 
 	seq_puts(s, "\n");
-	seq_printf(s, " %5s %5s %11lu %12lu %13lu %10lu %10lu %16s %8lu\n",
-			"Total", "", total_class_almost_full,
-			total_class_almost_empty, total_objs,
-			total_used_objs, total_pages, "", total_freeable);
+	seq_printf(s, " %5s %5s ", "Total", "");
+
+	for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++)
+		seq_printf(s, "%9lu ", inuse_totals[fg]);
+
+	seq_printf(s, "%13lu %10lu %10lu %16s %8lu\n",
+		   total_objs, total_used_objs, total_pages, "",
+		   total_freeable);
 
 	return 0;
 }