Re: [PATCH] [2/2] Optimize touch_time too

[Christoph Hellwig <hch@infradead.org>]

On Mon, Jul 06, 2009 at 09:24:47PM +0200, Andi Kleen wrote:
> 
> Do a similar optimization as earlier for touch_atime. Getting
> the lock in mnt_get_write is relatively costly, so try all
> avenues to avoid it first.
> 
> This patch is careful to still only update inode fields
> inside the lock region.
> 
> This didn't show up in benchmarks, but it's easy enough
> to do.
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> 
> ---
>  fs/inode.c |   43 +++++++++++++++++++++++--------------------
>  1 file changed, 23 insertions(+), 20 deletions(-)
> 
> Index: linux-2.6.31-rc1-ak/fs/inode.c
> ===================================================================
> --- linux-2.6.31-rc1-ak.orig/fs/inode.c
> +++ linux-2.6.31-rc1-ak/fs/inode.c
> @@ -1431,34 +1431,37 @@ void file_update_time(struct file *file)
>  {
>  	struct inode *inode = file->f_path.dentry->d_inode;
>  	struct timespec now;
> -	int sync_it = 0;
> -	int err;
> +	enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;

Looks good, and makes sense to keep thise in sync with
file_update_atime.