On 2015-05-09 04:41, Ryusuke Konishi wrote:
> 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.
I kind of assumed it would be called for every object returned by
kmem_cache_alloc(). In that case I have to do the initialization in
nilfs_sufile_alloc_cache_node() and remove this function.
Regards,
Andreas Rohner
> 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
