Among
Linux kernel
The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ...
developers, the -mm tree refers to a version of the kernel
source code
In computing, source code, or simply code, is any collection of code, with or without comment (computer programming), comments, written using a human-readable programming language, usually as plain text. The source code of a Computer program, p ...
maintained by
Andrew Morton.
The -mm kernel tree used to fill the role of Linux kernel development builds, formerly identified by odd version numbers following "2.6." (see
this section on Linux kernel version numbering). New and experimental code used to find its way into a 2.6.x-mm kernel build. Historically, the -mm tree focused on new developments for the memory management part of the kernel (mm).
Occasionally, the -mm tree was overloaded with new patches, so testing it became difficult. On September 17, 2007, Morton sent a mail saying that "this just isn't working any more". The presence of the new linux-next git repository has offloaded much of the work that made mm maintenance troublesome, allowing Morton to continue to use
quilt
A quilt is a multi-layered textile, traditionally composed of two or more layers of fabric or fiber. Commonly three layers are used with a filler material. These layers traditionally include a woven cloth top, a layer of batting or wadding, ...
to manage his series of "mmotm" (mm of the moment) patches.
Morton includes a subset of the mmotm patches in linux-next, which has a head called "linux-next/akpm". There is also a git tree that includes the patches that appear in releases of the mm tree. To get all of the mm patches at any given time, developers still need quilt or ad hoc shell scripts to apply the full set of patches.
References
README for the mmotm patches"This Just Isn't Working Any More"online listing of the linux-next/akpm git headrelease announcement of the mmotm snapshot by Andrew Morton on the Linux Kernel Mailing List, mentioning mmots
Linux kernel
{{linux-stub