On Tue, Jun 06, 2017 at 09:32:42AM -0400, Brian Foster wrote:
> 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?
Yes, we could. Will fix and resend.
--D
>
> Brian
>
> > }
> >
> > /*
> >
> > --
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