pahole - Finding holes in kernel structs

[Bakul Shah]

> >>>> So I ran the tool pahole over a 7.1 FreeBSD Kernel, and found that
> >>>> many of the struct had holes, and some of which could be rearranged to
> >>>> fill the gap.

...

> Certainly plugging holes can also be beneficial but just cautioning that 
> changes of this sort need to be checked if made to critical data 
> structures.  OTOH there aren't that many that matter in practice.

But why do it?  Are the benefits worth churning any ABIs?