Re: [PATCH 1/9] rbtree: Cache leftmost node internally

[Davidlohr Bueso]

On Sat, 15 Jul 2017, Christoph Hellwig wrote:

> Is the leftmost node so much more special than the rightmost one?
>
> Just asking because I have some code that caches both of them, but
> using your helpers would make it look very asymmetric..

Yeah, I thought of this, but ultimately decided that the leftmost
node was more used (rb_first vs rb_last calls) and probably not
worth adding the rightmost one which would endup enlarging the
structure even more.

That said, I do have some patches for the rbtree users to cache the
rightmost node, similarly to how it was done with the leftmost
before this patchset.

If folks don't mind enlarging rb_root_cached, I could definitely
add the rightmost, but it seems an overkill -- albeit asymmetric.

Thanks,
Davidlohr