linux-kernel - Re: [PATCH v4 03/12] ext4: factor out __es_alloc_extent() and __es_free

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Message-ID: <20230503142807.uzp4d3apt2abbpmg@quack3>
Date:   Wed, 3 May 2023 16:28:07 +0200
From:   Jan Kara <jack@...e.cz>
To:     Baokun Li <libaokun1@...wei.com>
Cc:     linux-ext4@...r.kernel.org, tytso@....edu,
        adilger.kernel@...ger.ca, jack@...e.cz, ritesh.list@...il.com,
        linux-kernel@...r.kernel.org, yi.zhang@...wei.com,
        yangerkun@...wei.com, yukuai3@...wei.com
Subject: Re: [PATCH v4 03/12] ext4: factor out __es_alloc_extent() and
 __es_free_extent()

On Mon 24-04-23 11:38:37, Baokun Li wrote:
> Factor out __es_alloc_extent() and __es_free_extent(), which only allocate
> and free extent_status in these two helpers.
> 
> The ext4_es_alloc_extent() function is split into __es_alloc_extent()
> and ext4_es_init_extent(). In __es_alloc_extent() we allocate memory using
> GFP_KERNEL | __GFP_NOFAIL | __GFP_ZERO if the memory allocation cannot
> fail, otherwise we use GFP_ATOMIC. and the ext4_es_init_extent() is used to
> initialize extent_status and update related variables after a successful
> allocation.
> 
> This is to prepare for the use of pre-allocated extent_status later.
> 
> Signed-off-by: Baokun Li <libaokun1@...wei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/extents_status.c | 30 +++++++++++++++++++-----------
>  1 file changed, 19 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index 573723b23d19..18665394392f 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -461,14 +461,17 @@ static inline bool ext4_es_must_keep(struct extent_status *es)
>  	return false;
>  }
>  
> -static struct extent_status *
> -ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len,
> -		     ext4_fsblk_t pblk)
> +static inline struct extent_status *__es_alloc_extent(bool nofail)
> +{
> +	if (!nofail)
> +		return kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC);
> +
> +	return kmem_cache_zalloc(ext4_es_cachep, GFP_KERNEL | __GFP_NOFAIL);
> +}
> +
> +static void ext4_es_init_extent(struct inode *inode, struct extent_status *es,
> +		ext4_lblk_t lblk, ext4_lblk_t len, ext4_fsblk_t pblk)
>  {
> -	struct extent_status *es;
> -	es = kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC);
> -	if (es == NULL)
> -		return NULL;
>  	es->es_lblk = lblk;
>  	es->es_len = len;
>  	es->es_pblk = pblk;
> @@ -483,8 +486,11 @@ ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len,
>  
>  	EXT4_I(inode)->i_es_all_nr++;
>  	percpu_counter_inc(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt);
> +}
>  
> -	return es;
> +static inline void __es_free_extent(struct extent_status *es)
> +{
> +	kmem_cache_free(ext4_es_cachep, es);
>  }
>  
>  static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
> @@ -501,7 +507,7 @@ static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
>  					s_es_stats.es_stats_shk_cnt);
>  	}
>  
> -	kmem_cache_free(ext4_es_cachep, es);
> +	__es_free_extent(es);
>  }
>  
>  /*
> @@ -802,10 +808,12 @@ static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
>  		}
>  	}
>  
> -	es = ext4_es_alloc_extent(inode, newes->es_lblk, newes->es_len,
> -				  newes->es_pblk);
> +	es = __es_alloc_extent(false);
>  	if (!es)
>  		return -ENOMEM;
> +	ext4_es_init_extent(inode, es, newes->es_lblk, newes->es_len,
> +			    newes->es_pblk);
> +
>  	rb_link_node(&es->rb_node, parent, p);
>  	rb_insert_color(&es->rb_node, &tree->root);
>  
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR