On Sat 19-01-13 11:17:14, Namjae Jeon wrote:
> From: Namjae Jeon <namjae.j...@samsung.com>
>
> This patch implements extent caching in case of file reading.
> While reading a file, currently, UDF reads metadata serially
> which takes a lot of time depending on the number of extents present
> in the file. Caching last accessd extent improves metadata read time.
> Instead of reading file metadata from start, now we read from
> the cached extent.
>
> This patch considerably improves the time spent by CPU in kernel mode.
> For example, while reading a 10.9 GB file using dd:
> Time before applying patch:
> 11677022208 bytes (10.9GB) copied, 1529.748921 seconds, 7.3MB/s
> real 25m 29.85s
> user 0m 12.41s
> sys 15m 34.75s
>
> Time after applying patch:
> 11677022208 bytes (10.9GB) copied, 1469.338231 seconds, 7.6MB/s
> real 24m 29.44s
> user 0m 15.73s
> sys 3m 27.61s
>
> Signed-off-by: Namjae Jeon <namjae.j...@samsung.com>
> Signed-off-by: Ashish Sangwan <a.sang...@samsung.com>
> Signed-off-by: Bonggil Bak <bg...@samsung.com>
Thanks for the patch Namjae. I did a few more changes to the patch.
Please check them whether you think they are OK.
diff --git a/fs/udf/ialloc.c b/fs/udf/ialloc.c
index 0cb208e..7e5aae4 100644
--- a/fs/udf/ialloc.c
+++ b/fs/udf/ialloc.c
@@ -117,10 +117,6 @@ struct inode *udf_new_inode(struct inode *dir, umode_t
mode, int *err)
iinfo->i_lenAlloc = 0;
iinfo->i_use = 0;
iinfo->i_checkpoint = 1;
- memset(&iinfo->cached_extent, 0, sizeof(struct udf_ext_cache));
- spin_lock_init(&(iinfo->i_extent_cache_lock));
- /* Mark extent cache as invalid for now */
- iinfo->cached_extent.lstart = -1;
if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_AD_IN_ICB))
iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
else if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 8494b8c..fb0c4c4 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1305,9 +1305,6 @@ static void udf_fill_inode(struct inode *inode, struct
buffer_head *bh)
iinfo->i_lenAlloc = 0;
iinfo->i_next_alloc_block = 0;
iinfo->i_next_alloc_goal = 0;
- memset(&iinfo->cached_extent, 0, sizeof(struct udf_ext_cache));
- spin_lock_init(&(iinfo->i_extent_cache_lock));
- iinfo->cached_extent.lstart = -1;
if (fe->descTag.tagIdent == cpu_to_le16(TAG_IDENT_EFE)) {
iinfo->i_efe = 1;
iinfo->i_use = 0;
Initialization now happens in udf_alloc_inode(). Also it's not necessary
to initialized cached_extent.epos when lstart == -1 - noone should look at
that.
@@ -2222,6 +2219,8 @@ int udf_read_extent_cache(struct inode *inode, loff_t
bcount,
*lbcount = iinfo->cached_extent.lstart;
memcpy(pos, &iinfo->cached_extent.epos,
sizeof(struct extent_position));
+ if (pos->bh)
+ get_bh(pos->bh);
spin_unlock(&iinfo->i_extent_cache_lock);
return 1;
} else
This is the most important - we should give buffer reference to pos->bh.
Caller will eventually free it right?
@@ -2236,8 +2235,7 @@ void udf_update_extent_cache(struct inode *inode, loff_t
estart,
struct udf_inode_info *iinfo = UDF_I(inode);
spin_lock(&iinfo->i_extent_cache_lock);
- if (pos->bh != NULL)
- /* Increase ref count */
+ if (pos->bh)
get_bh(pos->bh);
memcpy(&iinfo->cached_extent.epos, pos,
sizeof(struct extent_position));
@@ -2266,4 +2264,3 @@ void udf_clear_extent_cache(struct udf_inode_info *iinfo)
iinfo->cached_extent.lstart = -1;
}
}
-
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 186adbf..da8ce9f 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -134,6 +134,8 @@ static struct inode *udf_alloc_inode(struct super_block *sb)
ei->i_next_alloc_goal = 0;
ei->i_strat4096 = 0;
init_rwsem(&ei->i_data_sem);
+ ei->cached_extent.lstart = -1;
+ spin_lock_init(&ei->i_extent_cache_lock);
return &ei->vfs_inode;
}
Honza
--
Jan Kara <j...@suse.cz>
SUSE Labs, CR
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