Re: [PATCH 1/2] nilfs2: cleanup multi kmem_cache_{create,destroy} code

[Ryusuke Konishi <konishi.ryusuke-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org>]

On Tue, 6 Apr 2010 01:34:02 +0800, Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Hi KONISHI Ryusuke,
> 
> The following two patches are base on the tip of your nilfs2/for-next branch.
> A build and simple mount test has been passed.
> 
> Thanks,
> Li Hong
> 
> From 834d30bc730aab19f48474ad77733ef450e96e62 Mon Sep 17 00:00:00 2001
> From: Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Date: Tue, 6 Apr 2010 00:54:11 +0800
> Subject: [PATCH] nilfs2: cleanup multi kmem_cache_{create,destroy} code
> 
> This cleanup patch gives several improvements:
> 
>  - Moving all kmem_cache_{create_destroy} calls into one place, which removes
>  some small function calls, cleans up error check code and clarify the logic.
> 
>  - Mark all initial code in __init section.
> 
>  - Remove some very obvious comments.
> 
>  - Adjust some declarations.
> 
>  - Fix some space-tab issues.
> 
> Signed-off-by: Li Hong <lihong.hi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

OK, will queue it up.

Thanks,
Ryusuke Konishi

> ---
>  fs/nilfs2/btree.c   |   40 ----------------
>  fs/nilfs2/btree.h   |   23 ++++++++-
>  fs/nilfs2/segbuf.c  |   25 ----------
>  fs/nilfs2/segbuf.h  |    1 +
>  fs/nilfs2/segment.c |   36 --------------
>  fs/nilfs2/segment.h |    2 +
>  fs/nilfs2/super.c   |  128 ++++++++++++++++++++++++++------------------------
>  7 files changed, 90 insertions(+), 165 deletions(-)
> 
> diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
> index dcd4e1c..b27a342 100644
> --- a/fs/nilfs2/btree.c
> +++ b/fs/nilfs2/btree.c
> @@ -31,46 +31,6 @@
>  #include "alloc.h"
>  #include "dat.h"
>  
> -/**
> - * struct nilfs_btree_path - A path on which B-tree operations are executed
> - * @bp_bh: buffer head of node block
> - * @bp_sib_bh: buffer head of sibling node block
> - * @bp_index: index of child node
> - * @bp_oldreq: ptr end request for old ptr
> - * @bp_newreq: ptr alloc request for new ptr
> - * @bp_op: rebalance operation
> - */
> -struct nilfs_btree_path {
> -	struct buffer_head *bp_bh;
> -	struct buffer_head *bp_sib_bh;
> -	int bp_index;
> -	union nilfs_bmap_ptr_req bp_oldreq;
> -	union nilfs_bmap_ptr_req bp_newreq;
> -	struct nilfs_btnode_chkey_ctxt bp_ctxt;
> -	void (*bp_op)(struct nilfs_btree *, struct nilfs_btree_path *,
> -		      int, __u64 *, __u64 *);
> -};
> -
> -/*
> - * B-tree path operations
> - */
> -
> -static struct kmem_cache *nilfs_btree_path_cache;
> -
> -int __init nilfs_btree_path_cache_init(void)
> -{
> -	nilfs_btree_path_cache =
> -		kmem_cache_create("nilfs2_btree_path_cache",
> -				  sizeof(struct nilfs_btree_path) *
> -				  NILFS_BTREE_LEVEL_MAX, 0, 0, NULL);
> -	return (nilfs_btree_path_cache != NULL) ? 0 : -ENOMEM;
> -}
> -
> -void nilfs_btree_path_cache_destroy(void)
> -{
> -	kmem_cache_destroy(nilfs_btree_path_cache);
> -}
> -
>  static struct nilfs_btree_path *nilfs_btree_alloc_path(void)
>  {
>  	struct nilfs_btree_path *path;
> diff --git a/fs/nilfs2/btree.h b/fs/nilfs2/btree.h
> index 4b82d84..af638d5 100644
> --- a/fs/nilfs2/btree.h
> +++ b/fs/nilfs2/btree.h
> @@ -30,9 +30,6 @@
>  #include "btnode.h"
>  #include "bmap.h"
>  
> -struct nilfs_btree;
> -struct nilfs_btree_path;
> -
>  /**
>   * struct nilfs_btree - B-tree structure
>   * @bt_bmap: bmap base structure
> @@ -41,6 +38,25 @@ struct nilfs_btree {
>  	struct nilfs_bmap bt_bmap;
>  };
>  
> +/**
> + * struct nilfs_btree_path - A path on which B-tree operations are executed
> + * @bp_bh: buffer head of node block
> + * @bp_sib_bh: buffer head of sibling node block
> + * @bp_index: index of child node
> + * @bp_oldreq: ptr end request for old ptr
> + * @bp_newreq: ptr alloc request for new ptr
> + * @bp_op: rebalance operation
> + */
> +struct nilfs_btree_path {
> +	struct buffer_head *bp_bh;
> +	struct buffer_head *bp_sib_bh;
> +	int bp_index;
> +	union nilfs_bmap_ptr_req bp_oldreq;
> +	union nilfs_bmap_ptr_req bp_newreq;
> +	struct nilfs_btnode_chkey_ctxt bp_ctxt;
> +	void (*bp_op)(struct nilfs_btree *, struct nilfs_btree_path *,
> +		      int, __u64 *, __u64 *);
> +};
>  
>  #define NILFS_BTREE_ROOT_SIZE		NILFS_BMAP_SIZE
>  #define NILFS_BTREE_ROOT_NCHILDREN_MAX					\
> @@ -57,6 +73,7 @@ struct nilfs_btree {
>  #define NILFS_BTREE_KEY_MIN	((__u64)0)
>  #define NILFS_BTREE_KEY_MAX	(~(__u64)0)
>  
> +extern struct kmem_cache *nilfs_btree_path_cache;
>  
>  int nilfs_btree_path_cache_init(void);
>  void nilfs_btree_path_cache_destroy(void);
> diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
> index 6129a43..4a4b433 100644
> --- a/fs/nilfs2/segbuf.c
> +++ b/fs/nilfs2/segbuf.c
> @@ -39,35 +39,10 @@ struct nilfs_write_info {
>  	sector_t		blocknr;
>  };
>  
> -
>  static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
>  			      struct the_nilfs *nilfs);
>  static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
>  
> -
> -static struct kmem_cache *nilfs_segbuf_cachep;
> -
> -static void nilfs_segbuf_init_once(void *obj)
> -{
> -	memset(obj, 0, sizeof(struct nilfs_segment_buffer));
> -}
> -
> -int __init nilfs_init_segbuf_cache(void)
> -{
> -	nilfs_segbuf_cachep =
> -		kmem_cache_create("nilfs2_segbuf_cache",
> -				  sizeof(struct nilfs_segment_buffer),
> -				  0, SLAB_RECLAIM_ACCOUNT,
> -				  nilfs_segbuf_init_once);
> -
> -	return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0;
> -}
> -
> -void nilfs_destroy_segbuf_cache(void)
> -{
> -	kmem_cache_destroy(nilfs_segbuf_cachep);
> -}
> -
>  struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
>  {
>  	struct nilfs_segment_buffer *segbuf;
> diff --git a/fs/nilfs2/segbuf.h b/fs/nilfs2/segbuf.h
> index 94dfd35..cad9c7c 100644
> --- a/fs/nilfs2/segbuf.h
> +++ b/fs/nilfs2/segbuf.h
> @@ -121,6 +121,7 @@ struct nilfs_segment_buffer {
>  		    b_assoc_buffers))
>  #define NILFS_SEGBUF_BH_IS_LAST(bh, head)  ((bh)->b_assoc_buffers.next == head)
>  
> +extern struct kmem_cache *nilfs_segbuf_cachep;
>  
>  int __init nilfs_init_segbuf_cache(void);
>  void nilfs_destroy_segbuf_cache(void);
> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> index c161d89..1138713 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -115,42 +115,6 @@ static void nilfs_dispose_list(struct nilfs_sb_info *, struct list_head *,
>  #define nilfs_cnt32_lt(a, b)  nilfs_cnt32_gt(b, a)
>  #define nilfs_cnt32_le(a, b)  nilfs_cnt32_ge(b, a)
>  
> -/*
> - * Transaction
> - */
> -static struct kmem_cache *nilfs_transaction_cachep;
> -
> -/**
> - * nilfs_init_transaction_cache - create a cache for nilfs_transaction_info
> - *
> - * nilfs_init_transaction_cache() creates a slab cache for the struct
> - * nilfs_transaction_info.
> - *
> - * Return Value: On success, it returns 0. On error, one of the following
> - * negative error code is returned.
> - *
> - * %-ENOMEM - Insufficient memory available.
> - */
> -int nilfs_init_transaction_cache(void)
> -{
> -	nilfs_transaction_cachep =
> -		kmem_cache_create("nilfs2_transaction_cache",
> -				  sizeof(struct nilfs_transaction_info),
> -				  0, SLAB_RECLAIM_ACCOUNT, NULL);
> -	return (nilfs_transaction_cachep == NULL) ? -ENOMEM : 0;
> -}
> -
> -/**
> - * nilfs_destroy_transaction_cache - destroy the cache for transaction info
> - *
> - * nilfs_destroy_transaction_cache() frees the slab cache for the struct
> - * nilfs_transaction_info.
> - */
> -void nilfs_destroy_transaction_cache(void)
> -{
> -	kmem_cache_destroy(nilfs_transaction_cachep);
> -}
> -
>  static int nilfs_prepare_segment_lock(struct nilfs_transaction_info *ti)
>  {
>  	struct nilfs_transaction_info *cur_ti = current->journal_info;
> diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
> index 82dfd6a..2de218b 100644
> --- a/fs/nilfs2/segment.h
> +++ b/fs/nilfs2/segment.h
> @@ -219,6 +219,8 @@ enum {
>   */
>  #define NILFS_SC_DEFAULT_WATERMARK  3600
>  
> +/* super.c */
> +extern struct kmem_cache *nilfs_transaction_cachep;
>  
>  /* segment.c */
>  extern int nilfs_init_transaction_cache(void);
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index aa1ad6c..2e767bc 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -67,6 +67,11 @@ MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
>  		   "(NILFS)");
>  MODULE_LICENSE("GPL");
>  
> +struct kmem_cache *nilfs_inode_cachep;
> +struct kmem_cache *nilfs_transaction_cachep;
> +struct kmem_cache *nilfs_segbuf_cachep;
> +struct kmem_cache *nilfs_btree_path_cache;
> +
>  static int nilfs_remount(struct super_block *sb, int *flags, char *data);
>  
>  /**
> @@ -129,7 +134,6 @@ void nilfs_warning(struct super_block *sb, const char *function,
>  	va_end(args);
>  }
>  
> -static struct kmem_cache *nilfs_inode_cachep;
>  
>  struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
>  {
> @@ -155,34 +159,6 @@ void nilfs_destroy_inode(struct inode *inode)
>  	kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
>  }
>  
> -static void init_once(void *obj)
> -{
> -	struct nilfs_inode_info *ii = obj;
> -
> -	INIT_LIST_HEAD(&ii->i_dirty);
> -#ifdef CONFIG_NILFS_XATTR
> -	init_rwsem(&ii->xattr_sem);
> -#endif
> -	nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
> -	ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
> -	inode_init_once(&ii->vfs_inode);
> -}
> -
> -static int nilfs_init_inode_cache(void)
> -{
> -	nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
> -					       sizeof(struct nilfs_inode_info),
> -					       0, SLAB_RECLAIM_ACCOUNT,
> -					       init_once);
> -
> -	return (nilfs_inode_cachep == NULL) ? -ENOMEM : 0;
> -}
> -
> -static inline void nilfs_destroy_inode_cache(void)
> -{
> -	kmem_cache_destroy(nilfs_inode_cachep);
> -}
> -
>  static void nilfs_clear_inode(struct inode *inode)
>  {
>  	struct nilfs_inode_info *ii = NILFS_I(inode);
> @@ -1138,54 +1114,84 @@ struct file_system_type nilfs_fs_type = {
>  	.fs_flags = FS_REQUIRES_DEV,
>  };
>  
> -static int __init init_nilfs_fs(void)
> +static void nilfs_inode_init_once(void *obj)
>  {
> -	int err;
> -
> -	err = nilfs_init_inode_cache();
> -	if (err)
> -		goto failed;
> +	struct nilfs_inode_info *ii = obj;
>  
> -	err = nilfs_init_transaction_cache();
> -	if (err)
> -		goto failed_inode_cache;
> +	INIT_LIST_HEAD(&ii->i_dirty);
> +#ifdef CONFIG_NILFS_XATTR
> +	init_rwsem(&ii->xattr_sem);
> +#endif
> +	nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
> +	ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
> +	inode_init_once(&ii->vfs_inode);
> +}
>  
> -	err = nilfs_init_segbuf_cache();
> -	if (err)
> -		goto failed_transaction_cache;
> +static void nilfs_segbuf_init_once(void *obj)
> +{
> +	memset(obj, 0, sizeof(struct nilfs_segment_buffer));
> +}
>  
> -	err = nilfs_btree_path_cache_init();
> -	if (err)
> -		goto failed_segbuf_cache;
> +static void nilfs_destroy_cachep(void)
> +{
> +	 if (nilfs_inode_cachep)
> +		kmem_cache_destroy(nilfs_inode_cachep);
> +	 if (nilfs_transaction_cachep)
> +		kmem_cache_destroy(nilfs_transaction_cachep);
> +	 if (nilfs_segbuf_cachep)
> +		kmem_cache_destroy(nilfs_segbuf_cachep);
> +	 if (nilfs_btree_path_cache)
> +		kmem_cache_destroy(nilfs_btree_path_cache);
> +}
>  
> -	err = register_filesystem(&nilfs_fs_type);
> -	if (err)
> -		goto failed_btree_path_cache;
> +static int __init nilfs_init_cachep(void)
> +{
> +	nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
> +			sizeof(struct nilfs_inode_info), 0,
> +			SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
> +	if (!nilfs_inode_cachep)
> +		goto fail;
> +
> +	nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
> +			sizeof(struct nilfs_transaction_info), 0,
> +			SLAB_RECLAIM_ACCOUNT, NULL);
> +	if (!nilfs_transaction_cachep)
> +		goto fail;
> +
> +	nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
> +			sizeof(struct nilfs_segment_buffer), 0,
> +			SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
> +	if (!nilfs_segbuf_cachep)
> +		goto fail;
> +
> +	nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
> +			sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
> +			0, 0, NULL);
> +	if (!nilfs_btree_path_cache)
> +		goto fail;
>  
>  	return 0;
>  
> - failed_btree_path_cache:
> -	nilfs_btree_path_cache_destroy();
> -
> - failed_segbuf_cache:
> -	nilfs_destroy_segbuf_cache();
> +fail:
> +	nilfs_destroy_cachep();
> +	return -ENOMEM;
> +}
>  
> - failed_transaction_cache:
> -	nilfs_destroy_transaction_cache();
> +static int __init init_nilfs_fs(void)
> +{
> +	int err;
>  
> - failed_inode_cache:
> -	nilfs_destroy_inode_cache();
> +	err = nilfs_init_cachep();
> +	if (err)
> +		return err;
>  
> - failed:
> +	err = register_filesystem(&nilfs_fs_type);
>  	return err;
>  }
>  
>  static void __exit exit_nilfs_fs(void)
>  {
> -	nilfs_destroy_segbuf_cache();
> -	nilfs_destroy_transaction_cache();
> -	nilfs_destroy_inode_cache();
> -	nilfs_btree_path_cache_destroy();
> +	nilfs_destroy_cachep();
>  	unregister_filesystem(&nilfs_fs_type);
>  }
>  
> -- 
> 1.6.3.3
> 
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