Re: [GIT PULL] MM updates for 6.7-rc1

From: Andrew Morton
Date: Wed Nov 01 2023 - 17:57:02 EST


On Wed, 1 Nov 2023 14:54:47 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> vs bcachefs tree
> https://lkml.kernel.org/r/20230913093553.4290421e@xxxxxxxxxxxxxxxx
> I shall send Stephen's conversion patch in reply to this email.

From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Subject: bcachefs: convert to dynamically allocated shrinkers
Date: Tue, 12 Sep 2023 11:27:22 +1000

Link: https://lkml.kernel.org/r/20230913093553.4290421e@xxxxxxxxxxxxxxxx
Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Reviewed-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

fs/bcachefs/btree_cache.c | 22 ++++++++++++----------
fs/bcachefs/btree_key_cache.c | 21 ++++++++++++---------
fs/bcachefs/btree_types.h | 4 ++--
fs/bcachefs/fs.c | 2 +-
fs/bcachefs/sysfs.c | 2 +-
5 files changed, 28 insertions(+), 23 deletions(-)

--- a/fs/bcachefs/btree_cache.c~bcachefs-convert-to-dynamically-allocated-shrinkers
+++ a/fs/bcachefs/btree_cache.c
@@ -285,8 +285,7 @@ static int btree_node_write_and_reclaim(
static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
- struct bch_fs *c = container_of(shrink, struct bch_fs,
- btree_cache.shrink);
+ struct bch_fs *c = shrink->private_data;
struct btree_cache *bc = &c->btree_cache;
struct btree *b, *t;
unsigned long nr = sc->nr_to_scan;
@@ -384,8 +383,7 @@ out_nounlock:
static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
struct shrink_control *sc)
{
- struct bch_fs *c = container_of(shrink, struct bch_fs,
- btree_cache.shrink);
+ struct bch_fs *c = shrink->private_data;
struct btree_cache *bc = &c->btree_cache;

if (bch2_btree_shrinker_disabled)
@@ -400,7 +398,7 @@ void bch2_fs_btree_cache_exit(struct bch
struct btree *b;
unsigned i, flags;

- unregister_shrinker(&bc->shrink);
+ shrinker_free(bc->shrink);

/* vfree() can allocate memory: */
flags = memalloc_nofs_save();
@@ -454,6 +452,7 @@ void bch2_fs_btree_cache_exit(struct bch
int bch2_fs_btree_cache_init(struct bch_fs *c)
{
struct btree_cache *bc = &c->btree_cache;
+ struct shrinker *shrink;
unsigned i;
int ret = 0;

@@ -473,12 +472,15 @@ int bch2_fs_btree_cache_init(struct bch_

mutex_init(&c->verify_lock);

- bc->shrink.count_objects = bch2_btree_cache_count;
- bc->shrink.scan_objects = bch2_btree_cache_scan;
- bc->shrink.seeks = 4;
- ret = register_shrinker(&bc->shrink, "%s/btree_cache", c->name);
- if (ret)
+ shrink = shrinker_alloc(0, "%s/btree_cache", c->name);
+ if (!shrink)
goto err;
+ bc->shrink = shrink;
+ shrink->count_objects = bch2_btree_cache_count;
+ shrink->scan_objects = bch2_btree_cache_scan;
+ shrink->seeks = 4;
+ shrink->private_data = c;
+ shrinker_register(shrink);

return 0;
err:
--- a/fs/bcachefs/btree_key_cache.c~bcachefs-convert-to-dynamically-allocated-shrinkers
+++ a/fs/bcachefs/btree_key_cache.c
@@ -834,8 +834,7 @@ void bch2_btree_key_cache_drop(struct bt
static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
- struct bch_fs *c = container_of(shrink, struct bch_fs,
- btree_key_cache.shrink);
+ struct bch_fs *c = shrink->private_data;
struct btree_key_cache *bc = &c->btree_key_cache;
struct bucket_table *tbl;
struct bkey_cached *ck, *t;
@@ -932,8 +931,7 @@ out:
static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
struct shrink_control *sc)
{
- struct bch_fs *c = container_of(shrink, struct bch_fs,
- btree_key_cache.shrink);
+ struct bch_fs *c = shrink->private_data;
struct btree_key_cache *bc = &c->btree_key_cache;
long nr = atomic_long_read(&bc->nr_keys) -
atomic_long_read(&bc->nr_dirty);
@@ -953,7 +951,7 @@ void bch2_fs_btree_key_cache_exit(struct
int cpu;
#endif

- unregister_shrinker(&bc->shrink);
+ shrinker_free(bc->shrink);

mutex_lock(&bc->lock);

@@ -1027,6 +1025,7 @@ void bch2_fs_btree_key_cache_init_early(
int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
{
struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+ struct shrinker *shrink;

#ifdef __KERNEL__
bc->pcpu_freed = alloc_percpu(struct btree_key_cache_freelist);
@@ -1039,11 +1038,15 @@ int bch2_fs_btree_key_cache_init(struct

bc->table_init_done = true;

- bc->shrink.seeks = 0;
- bc->shrink.count_objects = bch2_btree_key_cache_count;
- bc->shrink.scan_objects = bch2_btree_key_cache_scan;
- if (register_shrinker(&bc->shrink, "%s/btree_key_cache", c->name))
+ shrink = shrinker_alloc(0, "%s/btree_key_cache", c->name);
+ if (!shrink)
return -BCH_ERR_ENOMEM_fs_btree_cache_init;
+ bc->shrink = shrink;
+ shrink->seeks = 0;
+ shrink->count_objects = bch2_btree_key_cache_count;
+ shrink->scan_objects = bch2_btree_key_cache_scan;
+ shrink->private_data = c;
+ shrinker_register(shrink);
return 0;
}

--- a/fs/bcachefs/btree_types.h~bcachefs-convert-to-dynamically-allocated-shrinkers
+++ a/fs/bcachefs/btree_types.h
@@ -163,7 +163,7 @@ struct btree_cache {
unsigned used;
unsigned reserve;
atomic_t dirty;
- struct shrinker shrink;
+ struct shrinker *shrink;

/*
* If we need to allocate memory for a new btree node and that
@@ -321,7 +321,7 @@ struct btree_key_cache {
bool table_init_done;
struct list_head freed_pcpu;
struct list_head freed_nonpcpu;
- struct shrinker shrink;
+ struct shrinker *shrink;
unsigned shrink_iter;
struct btree_key_cache_freelist __percpu *pcpu_freed;

--- a/fs/bcachefs/fs.c~bcachefs-convert-to-dynamically-allocated-shrinkers
+++ a/fs/bcachefs/fs.c
@@ -1904,7 +1904,7 @@ got_sb:
sb->s_flags |= SB_POSIXACL;
#endif

- sb->s_shrink.seeks = 0;
+ sb->s_shrink->seeks = 0;

vinode = bch2_vfs_inode_get(c, BCACHEFS_ROOT_SUBVOL_INUM);
ret = PTR_ERR_OR_ZERO(vinode);
--- a/fs/bcachefs/sysfs.c~bcachefs-convert-to-dynamically-allocated-shrinkers
+++ a/fs/bcachefs/sysfs.c
@@ -494,7 +494,7 @@ STORE(bch2_fs)

sc.gfp_mask = GFP_KERNEL;
sc.nr_to_scan = strtoul_or_return(buf);
- c->btree_cache.shrink.scan_objects(&c->btree_cache.shrink, &sc);
+ c->btree_cache.shrink->scan_objects(c->btree_cache.shrink, &sc);
}

if (attr == &sysfs_btree_wakeup)
_