# Linux 7.4 adopts new Core MM tree to restructure kernel memory management

> **Key takeaway:** Kernel maintainers have created a dedicated Core MM tree, split from Andrew Morton's long-standing MM branch, to streamline how core memory management patches flow into mainline Linux.

**Published:** 2026-10-26T11:42:27+00:00 
**Source:** Phoronix Benchmarks & Drivers 
**Category:** kernel-os 
**Canonical URL:** https://fosswire.org/news/linux-74-adopts-new-core-mm-tree-to-restructure-kernel-memor.html 

## Summary
The Linux kernel's memory management subsystem is undergoing a structural overhaul starting with the 7.4 release cycle. At the 2026 Linux Maintainers Summit, developers agreed to establish a new Core MM tree, with David Hildenbrand of Arm now serving as its maintainer and issuing the first pull request for Linux 7.4. This change aims to reduce the burden on Andrew Morton's MM tree, which has historically queued all memory management patches including broader work like DAMON/DAMOS.

The transition will proceed across multiple kernel cycles. For 7.4, patches will continue to arrive through multiple trees including slab, memblock, Andrew's MM, and the new core MM tree. The 7.5 cycle will begin consolidating component trees into a new MM integration tree, with the long-term goal of funneling all MM changes through a single integration point. This initial pull request includes Get User-Pages and Memory Hotplug code changes alongside the workflow infrastructure.

## How the Core MM reorganization works
- **Tree split rationale:** The new Core MM tree was created specifically to lighten the load on Andrew Morton's MM tree, which had become a bottleneck for all memory management patch flows.
- **Phased migration plan:** Linux 7.4 uses four parallel trees (slab, memblock, Andrew's MM, core MM); 7.5 will begin merging component trees into a unified MM integration tree; later cycles will gradually migrate remaining components.
- **Initial code changes:** The inaugural Core MM pull request for 7.4 includes patches touching Get User-Pages and Memory Hotplug functionality.
- **Maintainer transition:** David Hildenbrand of Arm has taken on maintainership of the new tree, marking a shift from the long-standing single-maintainer model for core MM patches.
- **linux-next integration:** The 7.4 cycle focused on establishing the MM integration workflow for linux-next, ensuring the new multi-tree structure functions correctly in the staging environment.

## Why it matters
This restructuring matters for downstream kernel developers and Linux distribution maintainers who track MM subsystem changes, as it alters where patches originate and how they must be monitored during the merge window. The consolidation into a single MM integration tree in future cycles should reduce integration complexity and make memory management changes more predictable for enterprise distributions and hardware vendors shipping custom kernels.