[PATCH/RESEND 0/5] z3fold optimizations and fixes

[Vitaly Wool]

This is a consolidation of z3fold optimizations and fixes done so far, revised after comments from Dan [1].
The coming patches are to be applied on top of the following commit:

commit 07cfe852286d5e314f8cd19781444e12a2b6cdf3
Author: zhong jiang <zhongjiang@xxxxxxxxxx>
Date:   Tue Dec 20 11:53:40 2016 +1100

    mm/z3fold.c: limit first_num to the actual range of possible buddy indexes

All the z3fold patches newer than this one are considered obsolete and should be substituted with this patch series. The coming patches have been verified with linux-next tree.

[1] https://lkml.org/lkml/2016/11/29/969