Re: [RFC v2 14/83] Add range node kmem cache.

[Nikolay Borisov]

On 10.03.2018 20:17, Andiry Xu wrote:
> From: Andiry Xu <jix024@xxxxxxxxxxx>
> 
> Range node specifies a range of [start, end]. and is managed by a red-black tree.
> NOVA uses range node to manage NVM allocator and inodes being used.
> 
> Signed-off-by: Andiry Xu <jix024@xxxxxxxxxxx>
> ---
>  fs/nova/nova.h  |  8 ++++++++
>  fs/nova/super.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
>  fs/nova/super.h |  2 ++
>  3 files changed, 52 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/nova/nova.h b/fs/nova/nova.h
> index ba7ffca..e0e85fb 100644
> --- a/fs/nova/nova.h
> +++ b/fs/nova/nova.h
> @@ -301,6 +301,14 @@ static inline u64 nova_get_epoch_id(struct super_block *sb)
>  }
>  
>  #include "inode.h"
> +
> +/* A node in the RB tree representing a range of pages */
> +struct nova_range_node {
> +	struct rb_node node;
> +	unsigned long range_low;
> +	unsigned long range_high;
> +};
> +
>  #include "bbuild.h"
>  
>  /* ====================================================== */
> diff --git a/fs/nova/super.c b/fs/nova/super.c
> index f41cc04..aec1cd3 100644
> --- a/fs/nova/super.c
> +++ b/fs/nova/super.c
> @@ -52,6 +52,7 @@ MODULE_PARM_DESC(nova_dbgmask, "Control debugging output");
>  static struct super_operations nova_sops;
>  
>  static struct kmem_cache *nova_inode_cachep;
> +static struct kmem_cache *nova_range_node_cachep;
>  
>  
>  /* FIXME: should the following variable be one per NOVA instance? */
> @@ -686,6 +687,20 @@ static void nova_put_super(struct super_block *sb)
>  	sb->s_fs_info = NULL;
>  }
>  
> +inline void nova_free_range_node(struct nova_range_node *node)
> +{
> +	kmem_cache_free(nova_range_node_cachep, node);
> +}
> +
> +inline struct nova_range_node *nova_alloc_range_node(struct super_block *sb)
> +{
> +	struct nova_range_node *p;
> +
> +	p = (struct nova_range_node *)
nit: needless cast
> +		kmem_cache_zalloc(nova_range_node_cachep, GFP_NOFS);
> +	return p;
> +}
> +
>  static struct inode *nova_alloc_inode(struct super_block *sb)
>  {
>  	struct nova_inode_info *vi;
> @@ -719,6 +734,17 @@ static void init_once(void *foo)
>  	inode_init_once(&vi->vfs_inode);
>  }
>  
> +static int __init init_rangenode_cache(void)
> +{
> +	nova_range_node_cachep = kmem_cache_create("nova_range_node_cache",
> +					sizeof(struct nova_range_node),
> +					0, (SLAB_RECLAIM_ACCOUNT |

> +					SLAB_MEM_SPREAD), NULL);
> +	if (nova_range_node_cachep == NULL)
> +		return -ENOMEM;
> +	return 0;
> +}
> +
>  static int __init init_inodecache(void)
>  {
>  	nova_inode_cachep = kmem_cache_create("nova_inode_cache",
> @@ -740,6 +766,11 @@ static void destroy_inodecache(void)
>  	kmem_cache_destroy(nova_inode_cachep);
>  }
>  
> +static void destroy_rangenode_cache(void)
> +{
> +	kmem_cache_destroy(nova_range_node_cachep);
> +}
> +
>  
>  /*
>   * the super block writes are all done "on the fly", so the
> @@ -781,20 +812,27 @@ static int __init init_nova_fs(void)
>  	nova_info("Arch new instructions support: CLWB %s\n",
>  			support_clwb ? "YES" : "NO");
>  
> -	rc = init_inodecache();
> +	rc = init_rangenode_cache();
>  	if (rc)
>  		goto out;
>  
> -	rc = register_filesystem(&nova_fs_type);
> +	rc = init_inodecache();
>  	if (rc)
>  		goto out1;
>  
> +	rc = register_filesystem(&nova_fs_type);
> +	if (rc)
> +		goto out2;
> +
>  out:
>  	NOVA_END_TIMING(init_t, init_time);
>  	return rc;
>  
> -out1:
> +out2:
>  	destroy_inodecache();
> +
> +out1:
> +	destroy_rangenode_cache();
>  	goto out;
>  }
>  
> @@ -802,6 +840,7 @@ static void __exit exit_nova_fs(void)
>  {
>  	unregister_filesystem(&nova_fs_type);
>  	destroy_inodecache();
> +	destroy_rangenode_cache();
>  }
>  
>  MODULE_AUTHOR("Andiry Xu <jix024@xxxxxxxxxxx>");
> diff --git a/fs/nova/super.h b/fs/nova/super.h
> index cb53908..b478080 100644
> --- a/fs/nova/super.h
> +++ b/fs/nova/super.h
> @@ -145,5 +145,7 @@ static inline struct nova_super_block *nova_get_super(struct super_block *sb)
>  }
>  
>  extern void nova_error_mng(struct super_block *sb, const char *fmt, ...);
> +extern struct nova_range_node *nova_alloc_range_node(struct super_block *sb);
> +extern void nova_free_range_node(struct nova_range_node *node);
>  
>  #endif
>