On Sun, 3 May 2015 12:05:17 +0200, Andreas Rohner wrote:
> This patch adds a kmem_cache to efficiently allocate SUFILE cache nodes.
> One cache node contains a certain number of unsigned 32 bit values and
> either a list_head, to string a number of nodes together into a linked
> list, or an rcu_head to be able to use the node with an rcu
> callback.
>
> These cache nodes can be used to cache small changes to the SUFILE and
> apply them later at segment construction.
>
> Signed-off-by: Andreas Rohner <andreas.rohner@xxxxxxx>
> ---
> fs/nilfs2/sufile.h | 14 ++++++++++++++
> fs/nilfs2/super.c | 14 ++++++++++++++
> 2 files changed, 28 insertions(+)
>
> diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
> index da78edf..520614f 100644
> --- a/fs/nilfs2/sufile.h
> +++ b/fs/nilfs2/sufile.h
> @@ -28,6 +28,20 @@
> #include <linux/nilfs2_fs.h>
> #include "mdt.h"
>
> +#define NILFS_SUFILE_CACHE_NODE_SHIFT 6
> +#define NILFS_SUFILE_CACHE_NODE_COUNT (1 << NILFS_SUFILE_CACHE_NODE_SHIFT)
> +
> +struct nilfs_sufile_cache_node {
> + __u32 values[NILFS_SUFILE_CACHE_NODE_COUNT];
> + union {
> + struct rcu_head rcu_head;
> + struct list_head list_head;
> + };
> + unsigned long index;
> +};
> +
> +extern struct kmem_cache *nilfs_sufile_node_cachep;
> +
> static inline int
> nilfs_sufile_live_blks_ext_supported(const struct inode *sufile)
> {
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index f47585b..97a30db 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -71,6 +71,7 @@ static 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;
> +struct kmem_cache *nilfs_sufile_node_cachep;
>
> static int nilfs_setup_super(struct super_block *sb, int is_mount);
> static int nilfs_remount(struct super_block *sb, int *flags, char *data);
> @@ -1397,6 +1398,11 @@ static void nilfs_segbuf_init_once(void *obj)
> memset(obj, 0, sizeof(struct nilfs_segment_buffer));
> }
>
> +static void nilfs_sufile_cache_node_init_once(void *obj)
> +{
> + memset(obj, 0, sizeof(struct nilfs_sufile_cache_node));
> +}
> +
Note that nilfs_sufile_cache_node_init_once() is only called when each
cache entry is allocated first time. It doesn't ensure each cache
entry is clean when it will be allocated with kmem_cache_alloc()
the second time and afterwards.
Regards,
Ryusuke Konishi
> static void nilfs_destroy_cachep(void)
> {
> /*
> @@ -1413,6 +1419,8 @@ static void nilfs_destroy_cachep(void)
> kmem_cache_destroy(nilfs_segbuf_cachep);
> if (nilfs_btree_path_cache)
> kmem_cache_destroy(nilfs_btree_path_cache);
> + if (nilfs_sufile_node_cachep)
> + kmem_cache_destroy(nilfs_sufile_node_cachep);
> }
>
> static int __init nilfs_init_cachep(void)
> @@ -1441,6 +1449,12 @@ static int __init nilfs_init_cachep(void)
> if (!nilfs_btree_path_cache)
> goto fail;
>
> + nilfs_sufile_node_cachep = kmem_cache_create("nilfs_sufile_node_cache",
> + sizeof(struct nilfs_sufile_cache_node), 0, 0,
> + nilfs_sufile_cache_node_init_once);
> + if (!nilfs_sufile_node_cachep)
> + goto fail;
> +
> return 0;
>
> fail:
> --
> 2.3.7
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
