Re: [PATCH] xfs: improve xfs_iext_destroy() by freeing extent indirection array directly

[Jeff Liu <jeff.liu@xxxxxxxxxx>]

On 09/20/2013 09:21 PM, Jeff Liu wrote:

> From: Jie Liu <jeff.liu@xxxxxxxxxx>
> 
> To free the incore file extents stores at the indirection array, we
> call the common routine xfs_iext_irec_remove() to remove a record
> from the array one at a time in reverse order, which will resize an
> extent indirection array repeatedly according to the array size.
> 
> This is not often the case to make a file with thousands extent records
> stores at an indirection array, but above operation is inefficient and
> could result in memory fragments.
> 
> This patch refine xfs_iext_destroy() by freeing the extent records from
> the indirection array directly in this case.
> 
> Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
> ---
>  fs/xfs/xfs_inode_fork.c |    7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_inode_fork.c b/fs/xfs/xfs_inode_fork.c
> index 02f1083..ba70f98 100644
> --- a/fs/xfs/xfs_inode_fork.c
> +++ b/fs/xfs/xfs_inode_fork.c
> @@ -1525,9 +1525,12 @@ xfs_iext_destroy(
>               int     nlists;
>  
>               nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
> -             for (erp_idx = nlists - 1; erp_idx >= 0 ; erp_idx--) {
> -                     xfs_iext_irec_remove(ifp, erp_idx);
> +             for (erp_idex = 0; erp_idx < nlists; erp_idx++) {

Sorry, here is a typo, s/erp_idex/erp_idx/, will resend it.

> +                     xfs_ext_irec_t  *erp = &ifp->if_u1.if_ext_irec[erp_idx];
> +                     if (erp->er_extbuf)
> +                             kmem_free(erp->er_extbuf);
>               }
> +             kmem_free(ifp->if_u1.if_ext_irec);
>               ifp->if_flags &= ~XFS_IFEXTIREC;
>       } else if (ifp->if_real_bytes) {
>               kmem_free(ifp->if_u1.if_extents);