On Fri, Jun 02, 2017 at 02:24:06PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Don't bother wandering our way through the leaf nodes when the caller
> issues a query_all; just zoom down the left side of the tree and walk
> rightwards along level zero.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/libxfs/xfs_btree.c | 44 +++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 39 insertions(+), 5 deletions(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index 3a673ba..07d75bc 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -4849,12 +4849,46 @@ xfs_btree_query_all(
> xfs_btree_query_range_fn fn,
> void *priv)
> {
> - union xfs_btree_irec low_rec;
> - union xfs_btree_irec high_rec;
> + union xfs_btree_rec *recp;
> + int stat;
> + int error;
> +
> + /*
> + * Find the leftmost record. The btree cursor must be set
> + * to the low record used to generate low_key.
> + */
> + memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
> + stat = 0;
> + error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
> + if (error)
> + goto out;
> +
> + /* Nothing? See if there's anything to the right. */
> + if (!stat) {
> + error = xfs_btree_increment(cur, 0, &stat);
> + if (error)
> + goto out;
> + }
>
> - memset(&low_rec, 0, sizeof(low_rec));
> - memset(&high_rec, 0xFF, sizeof(high_rec));
> - return xfs_btree_query_range(cur, &low_rec, &high_rec, fn, priv);
> + while (stat) {
> + /* Find the record. */
> + error = xfs_btree_get_rec(cur, &recp, &stat);
> + if (error || !stat)
> + break;
> +
> + /* Callback */
> + error = fn(cur, recp, priv);
> + if (error < 0 || error == XFS_BTREE_QUERY_RANGE_ABORT)
> + break;
> +
> + /* Move on to the next record. */
> + error = xfs_btree_increment(cur, 0, &stat);
> + if (error)
> + break;
> + }
> +
> +out:
> + return error;
This all looks quite similar to xfs_btree_simple_query_range(), minus
the associated key checks. I doubt the latter measurably affects the
performance of a btree walk. Could we call that function directly here?
Brian
> }
>
> /*
>
> --
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