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authorRoman Gushchin <roman.gushchin@linux.dev>2022-05-31 20:22:24 -0700
committerakpm <akpm@linux-foundation.org>2022-07-03 18:08:40 -0700
commite33c267ab70de4249d22d7eab1cc7d68a889bac2 (patch)
tree625ae2ff52e80b8a602acd0d459e781893495bdb /fs/super.c
parent5035ebc644aec92d55d1bbfe042f35341e4bffb5 (diff)
downloadlinux-e33c267ab70de4249d22d7eab1cc7d68a889bac2.tar.gz
mm: shrinkers: provide shrinkers with names
Currently shrinkers are anonymous objects.  For debugging purposes they
can be identified by count/scan function names, but it's not always
useful: e.g.  for superblock's shrinkers it's nice to have at least an
idea of to which superblock the shrinker belongs.

This commit adds names to shrinkers.  register_shrinker() and
prealloc_shrinker() functions are extended to take a format and arguments
to master a name.

In some cases it's not possible to determine a good name at the time when
a shrinker is allocated.  For such cases shrinker_debugfs_rename() is
provided.

The expected format is:
    <subsystem>-<shrinker_type>[:<instance>]-<id>
For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair.

After this change the shrinker debugfs directory looks like:
  $ cd /sys/kernel/debug/shrinker/
  $ ls
    dquota-cache-16     sb-devpts-28     sb-proc-47       sb-tmpfs-42
    mm-shadow-18        sb-devtmpfs-5    sb-proc-48       sb-tmpfs-43
    mm-zspool:zram0-34  sb-hugetlbfs-17  sb-pstore-31     sb-tmpfs-44
    rcu-kfree-0         sb-hugetlbfs-33  sb-rootfs-2      sb-tmpfs-49
    sb-aio-20           sb-iomem-12      sb-securityfs-6  sb-tracefs-13
    sb-anon_inodefs-15  sb-mqueue-21     sb-selinuxfs-22  sb-xfs:vda1-36
    sb-bdev-3           sb-nsfs-4        sb-sockfs-8      sb-zsmalloc-19
    sb-bpf-32           sb-pipefs-14     sb-sysfs-26      thp-deferred_split-10
    sb-btrfs:vda2-24    sb-proc-25       sb-tmpfs-1       thp-zero-9
    sb-cgroup2-30       sb-proc-39       sb-tmpfs-27      xfs-buf:vda1-37
    sb-configfs-23      sb-proc-41       sb-tmpfs-29      xfs-inodegc:vda1-38
    sb-dax-11           sb-proc-45       sb-tmpfs-35
    sb-debugfs-7        sb-proc-46       sb-tmpfs-40

[roman.gushchin@linux.dev: fix build warnings]
  Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle
  Reported-by: kernel test robot <lkp@intel.com>
Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/super.c')
-rw-r--r--fs/super.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/super.c b/fs/super.c
index 60f57c7bc0a6..4fca6657f442 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -265,7 +265,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
 	s->s_shrink.count_objects = super_cache_count;
 	s->s_shrink.batch = 1024;
 	s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE;
-	if (prealloc_shrinker(&s->s_shrink))
+	if (prealloc_shrinker(&s->s_shrink, "sb-%s", type->name))
 		goto fail;
 	if (list_lru_init_memcg(&s->s_dentry_lru, &s->s_shrink))
 		goto fail;
@@ -1288,6 +1288,8 @@ int get_tree_bdev(struct fs_context *fc,
 	} else {
 		s->s_mode = mode;
 		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
+		shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s",
+					fc->fs_type->name, s->s_id);
 		sb_set_blocksize(s, block_size(bdev));
 		error = fill_super(s, fc);
 		if (error) {
@@ -1363,6 +1365,8 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 	} else {
 		s->s_mode = mode;
 		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
+		shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s",
+					fs_type->name, s->s_id);
 		sb_set_blocksize(s, block_size(bdev));
 		error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
 		if (error) {