Re: [PATCH] mm: add ztree - new allocator for use via zpool API

ztree is a versatile backend for zswap and potentially zram. It got its name
due to the usage of red-black trees to store blocks of compressed objects.
These blocks consist of several consecutive pages and ztree keeps an integer
number of objects per block.

For zram, ztree has better worst case malloc() and free() times than zsmalloc,
does not deteriorate over time and has slightly worse but comparable compression
ratio. For zswap, ztree has better worst case malloc() and free() times than
z3fold, better compression ratio than z3fold and supports reclaim unlike zsmalloc.

Signed-off-by: Ananda Badmaev <redacted>

Signed-off-by: Vitaly Wool <redacted>