Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid free slab cache under spinlock

[Jaegeuk Kim]

Hi Chao,

One minor thing as below.

2014-03-29 (í), 11:29 +0800, Chao Yu:
> Move kmem_cache_free out of spinlock protection region for better performance.
> 
> Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
> ---
>  fs/f2fs/checkpoint.c |   27 +++++++++++++++++----------
>  fs/f2fs/node.c       |   15 ++++++++++++++-
>  2 files changed, 31 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index a80be51..d877f46 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -347,10 +347,11 @@ void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
>  	list_for_each_entry(orphan, head, list) {
>  		if (orphan->ino == ino) {
>  			list_del(&orphan->list);
> -			kmem_cache_free(orphan_entry_slab, orphan);
>  			f2fs_bug_on(sbi->n_orphans == 0);
>  			sbi->n_orphans--;
> -			break;
> +			spin_unlock(&sbi->orphan_inode_lock);
> +			kmem_cache_free(orphan_entry_slab, orphan);
> +			return;
>  		}
>  	}
>  	spin_unlock(&sbi->orphan_inode_lock);
> @@ -577,6 +578,7 @@ void set_dirty_dir_page(struct inode *inode, struct page *page)
>  {
>  	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
>  	struct dir_inode_entry *new;
> +	int ret = 0;
>  
>  	if (!S_ISDIR(inode->i_mode))
>  		return;
> @@ -586,12 +588,13 @@ void set_dirty_dir_page(struct inode *inode, struct page *page)
>  	INIT_LIST_HEAD(&new->list);
>  
>  	spin_lock(&sbi->dir_inode_lock);
> -	if (__add_dirty_inode(inode, new))
> -		kmem_cache_free(inode_entry_slab, new);
> -
> +	ret = __add_dirty_inode(inode, new);
>  	inode_inc_dirty_dents(inode);
>  	SetPagePrivate(page);
>  	spin_unlock(&sbi->dir_inode_lock);
> +
> +	if (ret)
> +		kmem_cache_free(inode_entry_slab, new);
>  }
>  
>  void add_dirty_dir_inode(struct inode *inode)
> @@ -599,20 +602,22 @@ void add_dirty_dir_inode(struct inode *inode)
>  	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
>  	struct dir_inode_entry *new =
>  			f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
> +	int ret = 0;
>  
>  	new->inode = inode;
>  	INIT_LIST_HEAD(&new->list);
>  
>  	spin_lock(&sbi->dir_inode_lock);
> -	if (__add_dirty_inode(inode, new))
> -		kmem_cache_free(inode_entry_slab, new);
> +	ret = __add_dirty_inode(inode, new);
>  	spin_unlock(&sbi->dir_inode_lock);
> +
> +	if (ret)
> +		kmem_cache_free(inode_entry_slab, new);
>  }
>  
>  void remove_dirty_dir_inode(struct inode *inode)
>  {
>  	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
> -
>  	struct list_head *this, *head;
>  
>  	if (!S_ISDIR(inode->i_mode))
> @@ -630,13 +635,15 @@ void remove_dirty_dir_inode(struct inode *inode)
>  		entry = list_entry(this, struct dir_inode_entry, list);
>  		if (entry->inode == inode) {
>  			list_del(&entry->list);
> -			kmem_cache_free(inode_entry_slab, entry);
>  			stat_dec_dirty_dir(sbi);
> -			break;
> +			spin_unlock(&sbi->dir_inode_lock);
> +			kmem_cache_free(inode_entry_slab, entry);
> +			goto done;
>  		}
>  	}
>  	spin_unlock(&sbi->dir_inode_lock);
>  
> +done:
>  	/* Only from the recovery routine */
>  	if (is_inode_flag_set(F2FS_I(inode), FI_DELAY_IPUT)) {
>  		clear_inode_flag(F2FS_I(inode), FI_DELAY_IPUT);
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index eced8d7..0021056 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1314,7 +1314,6 @@ static void __del_from_free_nid_list(struct f2fs_nm_info *nm_i,
>  {
>  	list_del(&i->list);
>  	radix_tree_delete(&nm_i->free_nid_root, i->nid);
> -	kmem_cache_free(free_nid_slab, i);
>  }
>  
>  static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
> @@ -1361,13 +1360,19 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
>  static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
>  {
>  	struct free_nid *i;
> +	bool need_free = false;
> +
>  	spin_lock(&nm_i->free_nid_list_lock);
>  	i = __lookup_free_nid_list(nm_i, nid);
>  	if (i && i->state == NID_NEW) {
>  		__del_from_free_nid_list(nm_i, i);
>  		nm_i->fcnt--;
> +		need_free = true;
>  	}
>  	spin_unlock(&nm_i->free_nid_list_lock);
> +
> +	if (need_free)
> +		kmem_cache_free(free_nid_slab, i);
>  }
>  
>  static void scan_nat_page(struct f2fs_nm_info *nm_i,
> @@ -1492,6 +1497,8 @@ void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
>  	f2fs_bug_on(!i || i->state != NID_ALLOC);
>  	__del_from_free_nid_list(nm_i, i);
>  	spin_unlock(&nm_i->free_nid_list_lock);
> +
> +	kmem_cache_free(free_nid_slab, i);
>  }
>  
>  /*
> @@ -1501,6 +1508,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
>  {
>  	struct f2fs_nm_info *nm_i = NM_I(sbi);
>  	struct free_nid *i;
> +	bool need_free = false;
>  
>  	if (!nid)
>  		return;
> @@ -1510,11 +1518,15 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
>  	f2fs_bug_on(!i || i->state != NID_ALLOC);
>  	if (!available_free_memory(nm_i, FREE_NIDS)) {
>  		__del_from_free_nid_list(nm_i, i);
> +		need_free = true;
>  	} else {
>  		i->state = NID_NEW;
>  		nm_i->fcnt++;
>  	}
>  	spin_unlock(&nm_i->free_nid_list_lock);
> +
> +	if (need_free)
> +		kmem_cache_free(free_nid_slab, i);
>  }
>  
>  void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
> @@ -1926,6 +1938,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
>  		f2fs_bug_on(i->state == NID_ALLOC);
>  		__del_from_free_nid_list(nm_i, i);
>  		nm_i->fcnt--;
> +		kmem_cache_free(free_nid_slab, i);

It seems that we need to do this too.

               spin_unlock(&nm_i->free_nid_list_lock);
               kmem_cache_free(free_nid_slab, i);
               spin_lock(&nm_i->free_nid_list_lock);

Right?

>  	}
>  	f2fs_bug_on(nm_i->fcnt);
>  	spin_unlock(&nm_i->free_nid_list_lock);

-- 
Jaegeuk Kim
Samsung

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