[PATCH 10/10] fs: super_cache_to_text()

[Kent Overstreet <kent.overstreet@linux.dev>]

Implement shrinker.to_text() for the superblock shrinker: print out nr
of dentries and inodes, total and shrinkable.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/super.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/super.c b/fs/super.c
index 5b0fea6ff1cd..d3e43127e311 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -36,6 +36,7 @@
 #include <linux/lockdep.h>
 #include <linux/user_namespace.h>
 #include <linux/fs_context.h>
+#include <linux/seq_buf.h>
 #include <uapi/linux/mount.h>
 #include "internal.h"
 
@@ -270,6 +271,16 @@ static unsigned long super_cache_count(struct shrinker *shrink,
 	return total_objects;
 }
 
+static void super_cache_to_text(struct seq_buf *out, struct shrinker *shrink)
+{
+	struct super_block *sb = shrink->private_data;
+
+	seq_buf_printf(out, "inodes:   total %zu shrinkable %lu\n",
+		       per_cpu_sum(sb->s_inodes_nr), list_lru_count(&sb->s_inode_lru));
+	seq_buf_printf(out, "dentries: toal %zu shrinkbale %lu\n",
+		       per_cpu_sum(sb->s_dentry_nr), list_lru_count(&sb->s_dentry_lru));
+}
+
 static void destroy_super_work(struct work_struct *work)
 {
 	struct super_block *s = container_of(work, struct super_block,
@@ -394,6 +405,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
 
 	s->s_shrink->scan_objects = super_cache_scan;
 	s->s_shrink->count_objects = super_cache_count;
+	s->s_shrink->to_text = super_cache_to_text;
 	s->s_shrink->batch = 1024;
 	s->s_shrink->private_data = s;
 
-- 
2.45.2