Re: [PATCH 26/94] Maple Tree: Add new data structure

From: Peter Zijlstra
Date: Fri May 14 2021 - 11:38:55 EST


On Fri, May 14, 2021 at 05:32:15PM +0200, Peter Zijlstra wrote:
> On Wed, Apr 28, 2021 at 03:36:02PM +0000, Liam Howlett wrote:
> > +static inline unsigned long mte_pivot(const struct maple_enode *mn,
> > + unsigned char piv)
> > +{
> > + struct maple_node *node = mte_to_node(mn);
> > +
> > + switch (mte_node_type(mn)) {
> > + case maple_arange_64:
> > + return node->ma64.pivot[piv];
> > + case maple_range_64:
> > + case maple_leaf_64:
> > + return node->mr64.pivot[piv];
> > + case maple_dense:
> > + default:
> > + return 0;
> > + }
> > +}

Why is @piv 'unsigned char' ? Does that actually generate better code on
any architecture?

At the same time; there's no bounds check.