Miao Xie
2010-Dec-01 08:09 UTC
[RFC PATCH 3/4] btrfs: reduce the times of mmap() in fill_inode_item()
With the old code, we must map the page every time we want to set a member
variable of the inode item, it is inefficient. We just do it at first.
By this way, we can improve the performance of file creation and deletion
by ~2%
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
fs/btrfs/inode.c | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 46b9d1a..2f0c742 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2539,6 +2539,16 @@ static void fill_inode_item(struct btrfs_trans_handle
*trans,
struct btrfs_inode_item *item,
struct inode *inode)
{
+ int unmap_on_exit;
+
+ unmap_on_exit = (leaf->map_token == NULL);
+ if (unmap_on_exit)
+ map_extent_buffer(leaf, (unsigned long)item,
+ sizeof(*item), &leaf->map_token,
+ &leaf->kaddr, &leaf->map_start,
+ &leaf->map_len, KM_USER1);
+
+
btrfs_set_inode_uid(leaf, item, inode->i_uid);
btrfs_set_inode_gid(leaf, item, inode->i_gid);
btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
@@ -2567,6 +2577,11 @@ static void fill_inode_item(struct btrfs_trans_handle
*trans,
btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
+
+ if (unmap_on_exit && leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
}
/*
--
1.7.0.1
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