btrfs: add more __cold annotations

The __cold functions are placed to a special section, as they're
expected to be called rarely. This could help i-cache prefetches or help
compiler to decide which branches are more/less likely to be taken
without any other annotations needed.

Though we can't add more __exit annotations, it's still possible to add
__cold (that's also added with __exit). That way the following function
categories are tagged:

- printf wrappers, error messages
- exit helpers

Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/backref.c

@@ -170,7 +170,7 @@ int __init btrfs_prelim_ref_init(void)
 	return 0;
 }
 
-void btrfs_prelim_ref_exit(void)
+void __cold btrfs_prelim_ref_exit(void)
 {
 	kmem_cache_destroy(btrfs_prelim_ref_cache);
 }

fs/btrfs/backref.h

@@ -73,7 +73,7 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
 int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr);
 
 int __init btrfs_prelim_ref_init(void);
-void btrfs_prelim_ref_exit(void);
+void __cold btrfs_prelim_ref_exit(void);
 
 struct prelim_ref {
 	struct rb_node rbnode;

fs/btrfs/compression.c

@@ -1133,7 +1133,7 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
 	return ret;
 }
 
-void btrfs_exit_compress(void)
+void __cold btrfs_exit_compress(void)
 {
 	free_workspaces();
 }

fs/btrfs/compression.h

@@ -76,7 +76,7 @@ struct compressed_bio {
 };
 
 void __init btrfs_init_compress(void);
-void btrfs_exit_compress(void);
+void __cold btrfs_exit_compress(void);
 
 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
 			 u64 start, struct page **pages,

fs/btrfs/ctree.h

@@ -3204,7 +3204,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb);
 void btrfs_destroy_inode(struct inode *inode);
 int btrfs_drop_inode(struct inode *inode);
 int __init btrfs_init_cachep(void);
-void btrfs_destroy_cachep(void);
+void __cold btrfs_destroy_cachep(void);
 long btrfs_ioctl_trans_end(struct file *file);
 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
 			 struct btrfs_root *root, int *was_new);
@@ -3255,7 +3255,7 @@ ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen,
 
 /* file.c */
 int __init btrfs_auto_defrag_init(void);
-void btrfs_auto_defrag_exit(void);
+void __cold btrfs_auto_defrag_exit(void);
 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
 			   struct btrfs_inode *inode);
 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info);
@@ -3290,7 +3290,7 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 
 /* sysfs.c */
 int __init btrfs_init_sysfs(void);
-void btrfs_exit_sysfs(void);
+void __cold btrfs_exit_sysfs(void);
 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info);
 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info);
 
@@ -3302,13 +3302,14 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 			unsigned long new_flags);
 int btrfs_sync_fs(struct super_block *sb, int wait);
 
-static inline __printf(2, 3)
+static inline __printf(2, 3) __cold
 void btrfs_no_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 {
 }
 
 #ifdef CONFIG_PRINTK
 __printf(2, 3)
+__cold
 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...);
 #else
 #define btrfs_printk(fs_info, fmt, args...) \

fs/btrfs/delayed-inode.c

@@ -42,7 +42,7 @@ int __init btrfs_delayed_inode_init(void)
 	return 0;
 }
 
-void btrfs_delayed_inode_exit(void)
+void __cold btrfs_delayed_inode_exit(void)
 {
 	kmem_cache_destroy(delayed_node_cache);
 }

fs/btrfs/delayed-inode.h

@@ -149,7 +149,7 @@ int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
 
 /* for init */
 int __init btrfs_delayed_inode_init(void);
-void btrfs_delayed_inode_exit(void);
+void __cold btrfs_delayed_inode_exit(void);
 
 /* for debugging */
 void btrfs_assert_delayed_root_empty(struct btrfs_fs_info *fs_info);

fs/btrfs/delayed-ref.c

@@ -930,7 +930,7 @@ btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 byt
 	return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 }
 
-void btrfs_delayed_ref_exit(void)
+void __cold btrfs_delayed_ref_exit(void)
 {
 	kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 	kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);

fs/btrfs/delayed-ref.h

@@ -204,7 +204,7 @@ extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
 extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
 
 int __init btrfs_delayed_ref_init(void);
-void btrfs_delayed_ref_exit(void);
+void __cold btrfs_delayed_ref_exit(void);
 
 static inline struct btrfs_delayed_extent_op *
 btrfs_alloc_delayed_extent_op(void)

fs/btrfs/disk-io.c

@@ -110,7 +110,7 @@ int __init btrfs_end_io_wq_init(void)
 	return 0;
 }
 
-void btrfs_end_io_wq_exit(void)
+void __cold btrfs_end_io_wq_exit(void)
 {
 	kmem_cache_destroy(btrfs_end_io_wq_cache);
 }

fs/btrfs/disk-io.h

@@ -153,7 +153,7 @@ struct extent_map *btree_get_extent(struct btrfs_inode *inode,
 		int create);
 int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
 int __init btrfs_end_io_wq_init(void);
-void btrfs_end_io_wq_exit(void);
+void __cold btrfs_end_io_wq_exit(void);
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 void btrfs_init_lockdep(void);

fs/btrfs/extent_io.c

@@ -187,7 +187,7 @@ int __init extent_io_init(void)
 	return -ENOMEM;
 }
 
-void extent_io_exit(void)
+void __cold extent_io_exit(void)
 {
 	btrfs_leak_debug_check();
 

fs/btrfs/extent_io.h

@@ -286,7 +286,7 @@ int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
 			  get_extent_t *get_extent, int mirror_num);
 int __init extent_io_init(void);
-void extent_io_exit(void);
+void __cold extent_io_exit(void);
 
 u64 count_range_bits(struct extent_io_tree *tree,
 		     u64 *start, u64 search_end,

fs/btrfs/extent_map.c

@@ -19,7 +19,7 @@ int __init extent_map_init(void)
 	return 0;
 }
 
-void extent_map_exit(void)
+void __cold extent_map_exit(void)
 {
 	kmem_cache_destroy(extent_map_cache);
 }

fs/btrfs/extent_map.h

@@ -86,7 +86,7 @@ void replace_extent_mapping(struct extent_map_tree *tree,
 struct extent_map *alloc_extent_map(void);
 void free_extent_map(struct extent_map *em);
 int __init extent_map_init(void);
-void extent_map_exit(void);
+void __cold extent_map_exit(void);
 int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
 void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
 struct extent_map *search_extent_mapping(struct extent_map_tree *tree,

fs/btrfs/file.c

@@ -3378,7 +3378,7 @@ const struct file_operations btrfs_file_operations = {
 	.dedupe_file_range = btrfs_dedupe_file_range,
 };
 
-void btrfs_auto_defrag_exit(void)
+void __cold btrfs_auto_defrag_exit(void)
 {
 	kmem_cache_destroy(btrfs_inode_defrag_cachep);
 }

fs/btrfs/inode.c

@@ -9478,7 +9478,7 @@ static void init_once(void *foo)
 	inode_init_once(&ei->vfs_inode);
 }
 
-void btrfs_destroy_cachep(void)
+void __cold btrfs_destroy_cachep(void)
 {
 	/*
 	 * Make sure all delayed rcu free inodes are flushed before we

fs/btrfs/ordered-data.c

@@ -1154,7 +1154,7 @@ int __init ordered_data_init(void)
 	return 0;
 }
 
-void ordered_data_exit(void)
+void __cold ordered_data_exit(void)
 {
 	kmem_cache_destroy(btrfs_ordered_extent_cache);
 }

fs/btrfs/ordered-data.h

@@ -217,5 +217,5 @@ void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *log, u64 transid);
 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid);
 int __init ordered_data_init(void);
-void ordered_data_exit(void);
+void __cold ordered_data_exit(void);
 #endif

fs/btrfs/send.c

@@ -270,6 +270,7 @@ struct name_cache_entry {
 	char name[];
 };
 
+__cold
 static void inconsistent_snapshot_error(struct send_ctx *sctx,
 					enum btrfs_compare_tree_result result,
 					const char *what)

fs/btrfs/super.c

@@ -2333,7 +2333,7 @@ static int __init btrfs_interface_init(void)
 	return misc_register(&btrfs_misc);
 }
 
-static void btrfs_interface_exit(void)
+static __cold void btrfs_interface_exit(void)
 {
 	misc_deregister(&btrfs_misc);
 }

fs/btrfs/sysfs.c

@@ -923,7 +923,7 @@ int __init btrfs_init_sysfs(void)
 	return ret;
 }
 
-void btrfs_exit_sysfs(void)
+void __cold btrfs_exit_sysfs(void)
 {
 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 	kset_unregister(btrfs_kset);

fs/btrfs/tree-checker.c

@@ -52,6 +52,7 @@
  * Allows callers to customize the output.
  */
 __printf(4, 5)
+__cold
 static void generic_err(const struct btrfs_fs_info *fs_info,
 			const struct extent_buffer *eb, int slot,
 			const char *fmt, ...)
@@ -76,6 +77,7 @@ static void generic_err(const struct btrfs_fs_info *fs_info,
  * offset has its own meaning.
  */
 __printf(4, 5)
+__cold
 static void file_extent_err(const struct btrfs_fs_info *fs_info,
 			    const struct extent_buffer *eb, int slot,
 			    const char *fmt, ...)
@@ -229,6 +231,7 @@ static int check_csum_item(struct btrfs_fs_info *fs_info,
  * which represents inode number
  */
 __printf(4, 5)
+__cold
 static void dir_item_err(const struct btrfs_fs_info *fs_info,
 			 const struct extent_buffer *eb, int slot,
 			 const char *fmt, ...)