In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the s_shrink, so that it can be freed asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU read-side critical section when releasing the struct super_block. Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> --- fs/btrfs/super.c | 2 +- fs/kernfs/mount.c | 2 +- fs/proc/root.c | 2 +- fs/super.c | 37 +++++++++++++++++++++---------------- include/linux/fs.h | 2 +- 5 files changed, 25 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index f1dd172d8d5b..fad4ded26c80 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1513,7 +1513,7 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, error = -EBUSY; } else { snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); - shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name, + shrinker_debugfs_rename(s->s_shrink, "sb-%s:%s", fs_type->name, s->s_id); btrfs_sb(s)->bdev_holder = fs_type; error = btrfs_fill_super(s, fs_devices, data); diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index d49606accb07..2657ff1181f1 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -256,7 +256,7 @@ static int kernfs_fill_super(struct super_block *sb, struct kernfs_fs_context *k sb->s_time_gran = 1; /* sysfs dentries and inodes don't require IO to create */ - sb->s_shrink.seeks = 0; + sb->s_shrink->seeks = 0; /* get root inode, initialize and unlock it */ down_read(&kf_root->kernfs_rwsem); diff --git a/fs/proc/root.c b/fs/proc/root.c index a86e65a608da..22b78b28b477 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -188,7 +188,7 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc) s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; /* procfs dentries and inodes don't require IO to create */ - s->s_shrink.seeks = 0; + s->s_shrink->seeks = 0; pde_get(&proc_root); root_inode = proc_get_inode(s, &proc_root); diff --git a/fs/super.c b/fs/super.c index e781226e2880..04643fd80886 100644 --- a/fs/super.c +++ b/fs/super.c @@ -67,7 +67,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink, long dentries; long inodes; - sb = container_of(shrink, struct super_block, s_shrink); + sb = shrink->private_data; /* * Deadlock avoidance. We may hold various FS locks, and we don't want @@ -120,7 +120,7 @@ static unsigned long super_cache_count(struct shrinker *shrink, struct super_block *sb; long total_objects = 0; - sb = container_of(shrink, struct super_block, s_shrink); + sb = shrink->private_data; /* * We don't call trylock_super() here as it is a scalability bottleneck, @@ -182,7 +182,8 @@ static void destroy_unused_super(struct super_block *s) security_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); - free_prealloced_shrinker(&s->s_shrink); + if (s->s_shrink) + shrinker_free_non_registered(s->s_shrink); /* no delays needed */ destroy_super_work(&s->destroy_work); } @@ -259,16 +260,20 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, s->s_time_min = TIME64_MIN; s->s_time_max = TIME64_MAX; - s->s_shrink.seeks = DEFAULT_SEEKS; - s->s_shrink.scan_objects = super_cache_scan; - 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, "sb-%s", type->name)) + s->s_shrink = shrinker_alloc(SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE, + "sb-%s", type->name); + if (!s->s_shrink) goto fail; - if (list_lru_init_memcg(&s->s_dentry_lru, &s->s_shrink)) + + s->s_shrink->seeks = DEFAULT_SEEKS; + s->s_shrink->scan_objects = super_cache_scan; + s->s_shrink->count_objects = super_cache_count; + s->s_shrink->batch = 1024; + s->s_shrink->private_data = s; + + if (list_lru_init_memcg(&s->s_dentry_lru, s->s_shrink)) goto fail; - if (list_lru_init_memcg(&s->s_inode_lru, &s->s_shrink)) + if (list_lru_init_memcg(&s->s_inode_lru, s->s_shrink)) goto fail; return s; @@ -326,7 +331,7 @@ void deactivate_locked_super(struct super_block *s) { struct file_system_type *fs = s->s_type; if (atomic_dec_and_test(&s->s_active)) { - unregister_shrinker(&s->s_shrink); + shrinker_unregister(s->s_shrink); fs->kill_sb(s); /* @@ -599,7 +604,7 @@ struct super_block *sget_fc(struct fs_context *fc, hlist_add_head(&s->s_instances, &s->s_type->fs_supers); spin_unlock(&sb_lock); get_filesystem(s->s_type); - register_shrinker_prepared(&s->s_shrink); + shrinker_register(s->s_shrink); return s; share_extant_sb: @@ -678,7 +683,7 @@ struct super_block *sget(struct file_system_type *type, hlist_add_head(&s->s_instances, &type->fs_supers); spin_unlock(&sb_lock); get_filesystem(type); - register_shrinker_prepared(&s->s_shrink); + shrinker_register(s->s_shrink); return s; } EXPORT_SYMBOL(sget); @@ -1312,7 +1317,7 @@ int get_tree_bdev(struct fs_context *fc, down_write(&s->s_umount); } else { snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); - shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", + 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); @@ -1385,7 +1390,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, down_write(&s->s_umount); } else { snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); - shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", + 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); diff --git a/include/linux/fs.h b/include/linux/fs.h index b4dca987a5d8..92748fc368b2 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1231,7 +1231,7 @@ struct super_block { const struct dentry_operations *s_d_op; /* default d_op for dentries */ - struct shrinker s_shrink; /* per-sb shrinker handle */ + struct shrinker *s_shrink; /* per-sb shrinker handle */ /* Number of inodes with nlink == 0 but still referenced */ atomic_long_t s_remove_count; -- 2.30.2