NVDIMM Block Reclamation for Wear Leveling and Memory Availability

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Solution Overview

Problem

Non-volatile dual in-line memory modules (NVDIMMs) face issues with poor fatigue resistance and limited write times, leading to unbalanced wear among memory blocks, which affects their service life and performance.

Innovation Solution

A memory block reclamation method and apparatus that involves a medium controller receiving an unmap command with memory logical address information to reclaim memory blocks, deleting the mapping relationship, and adding the physical address to an idle list, enhancing wear leveling and improving storage performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If memory blocks are not reclaimed promptly, then wear leveling is improved, but memory availability and reclamation speed deteriorate

Engineering Contradiction:
Improvewear leveling effectVSAvoidmemory block reclamation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The medium controller proactively identifies and reclaims memory blocks before they reach maximum write times. By monitoring write counts and initiating reclamation operations in advance, the system prevents wear imbalance while maintaining high memory availability. The controller sends unmap commands to reclaim memory blocks that are no longer needed, converting them to available blocks before they become problematic.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous monitoring of memory block write times and wear levels. Based on this feedback, the medium controller dynamically adjusts reclamation operations, identifying blocks that need reclamation and executing unmap commands accordingly. This closed-loop control ensures optimal wear leveling while maintaining memory performance.

Inventive Principle:
Principle #23Feedback

2Duration of action of stationary object

If memory management operations are increased, then service life is prolonged, but system complexity increases

Engineering Contradiction:
Improveservice life of NVDIMMVSAvoidmemory management complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The medium controller autonomously manages memory block reclamation without requiring complex host intervention. It independently monitors write times, identifies blocks for reclamation, and executes unmap commands. This self-managing approach extends NVDIMM service life while keeping the control logic centralized and manageable within the medium controller.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines wear leveling, garbage collection, and memory management functions into a unified medium controller. By merging these operations under a single control entity that communicates via NVDIMM-P protocol, the system achieves comprehensive memory management without the complexity of multiple independent management systems.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4345629B1Memory block reclamation method and apparatus
Publication Date: 2026.01.14 HUAWEI TECH CO LTD
  • EP4345629B1 patent drawingFigure 1
  • EP4345629B1 patent drawingFigure 2
  • EP4345629B1 patent drawingFigure 3

AI summary

A memory block reclamation method and apparatus are provided. The method includes: receiving, by a medium controller, an unmap command sent by a memory controller, where the unmap command includes memory logical address information of a to-be-reclaimed memory block (S201); and reclaiming, by the medium controller, the memory block based on the memory logical address information, where the reclaimed memory block is an available memory block (S202). After receiving the unmap command sent by the memory controller, the medium controller releases a corresponding memory block and reclaims the memory block, based on the memory logical address information of the to-be-reclaimed memory block included in the unmap command, thereby enhancing a medium management operation effect of the medium controller, improving storage performance of an NVDIMM, and prolonging a service life of the NVDIMM.