I don't like adding additional levels of macros to build the augmented rbtree callbacks. OTOH, all of the existing callbacks compute the max (within the subtree) of a per-node scalar property. So, I guess I could do a RB_DECLARE_MAX_CALLBACKS, and one of its arguments would tell it how to compute the per-node scalar property, and it would generate the code that both computes the max within the subtree and assigns it into the augmented variable for the subtree's root. I will prepare a v2 version of this patchset that does that.
On Mon, Jul 1, 2019 at 7:40 AM Peter Zijlstra <pet...@infradead.org> wrote: > > On Mon, Jul 01, 2019 at 09:46:30AM +0200, Peter Zijlstra wrote: > > On Fri, Jun 28, 2019 at 05:49:52PM -0700, Michel Lespinasse wrote: > > > > The motivation for this change is that I want to introduce augmented > > > rbtree > > > uses where the augmented data for the subtree is a struct instead of a > > > scalar. > > > Can't we have a helper macro that converts an old (scalar) style compute > > into a new style compute and avoid this unfortunate and error prone > > copy/pasta ? > > Or add a RBEQUAL argument that does: > > - if (node->RBAUGMENTED == augmented) > + if (RBEQUAL(&node->RBAUGMENTED, &augmented)) > > With a bit of foo you can even provide a default implementation that > does: *a == *b. > > See GEN_UNARY_RMWcc() for how to do that. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies.
