mimalloc

Microsoft open source library

mimalloc

Original authors	Daan Leijen / Microsoft Research
Developer	Microsoft
Initial release	July 2019; 6 years ago (2019-07)

Stable release	3.1.5^[1] Edit this on Wikidata / 6 October 2025
Repository	github.com/microsoft/mimalloc
Written in	C
Operating system	Windows, FreeBSD, NetBSD, DragonFly BSD, macOS, Linux
Type	Software library
License	MIT License
Website	microsoft.github.io/mimalloc/

mimalloc (pronounced "me-malloc") is a free and open-source compact general-purpose memory allocator developed by Microsoft ^[2] with focus on performance characteristics. The library is about 11000 lines of code and works as a drop-in replacement for malloc of the C standard library ^[3] and requires no additional code changes.^[4] mimalloc was initially developed for the run-time systems of the Lean and Koka languages. Notable design aspects include free list sharding, eager page reset, and first-class heaps. It can co-exist with other memory allocators linked to the same program. mimalloc is available on Windows, Mac OS X, Linux and *BSD.^[5] The source code is licensed under MIT License and available on GitHub.^[6]

References

[edit ]

^ "Release 3.1.5". 14 June 2025. Retrieved 24 June 2025.
^ "Maruf Ali: Investigation of Memory Allocators" (PDF).
^ "Microsoft releases optimized malloc() as open source - Slashdot". slashdot.org.
^ "Analysis of mimalloc". Develop Paper. September 11, 2019.^{[dead link ]}
^ "Google Translate". translate.google.com. 25 June 2019.
^ "microsoft/mimalloc". July 5, 2020 – via GitHub.

External links

[edit ]

v t e Memory management
Memory management as a function of an operating system
Hardware	Memory management unit (MMU) Translation lookaside buffer (TLB) Input–output memory management unit (IOMMU)
Virtual memory	Demand paging Memory paging Page table Virtual memory compression
Segmentation	Protected mode Real mode Virtual 8086 mode x86 memory segmentation
Allocator	dlmalloc Hoard jemalloc libumem mimalloc ptmalloc
Manual means	Static memory allocation C dynamic memory allocation new and delete (C++)
Garbage collection	Automatic Reference Counting Boehm garbage collector Cheney's algorithm Concurrent mark sweep collector Finalizer Garbage Garbage-first collector Mark–compact algorithm Reference counting Tracing garbage collection Strong reference Weak reference
Safety	Buffer overflow Buffer over-read Dangling pointer Stack overflow
Issues	Fragmentation Memory leak Unreachable memory
Other	Automatic variable Constructors Destructors International Symposium on Memory Management Region-based memory management Memory pool
Memory management Virtual memory Automatic memory management Memory management algorithms Memory management software

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t
e

Microsoft free and open-source software (FOSS)

Overview

Software

Applications	3D Movie Maker Atom Conference XP Family.Show File Manager Open Live Writer Microsoft Edit Microsoft PowerToys Terminal Windows Calculator Windows Console Windows Package Manager WorldWide Telescope XML Notepad
Video games	Allegiance Zork
Programming languages	Bosque C# Dafny F# F* GW-BASIC IronPython IronRuby Lean P Power Fx PowerShell Project Verona Q# Small Basic Online TypeScript Visual Basic
Frameworks, development tools	.NET .NET Framework .NET Gadgeteer .NET MAUI .NET Micro Framework AirSim ASP.NET ASP.NET AJAX ASP.NET Core ASP.NET MVC ASP.NET Razor ASP.NET Web Forms Avalonia Babylon.js BitFunnel Blazor C++/WinRT CCF ChakraCore CLR Profiler Dapr DeepSpeed DiskSpd Dryad Dynamic Language Runtime eBPF on Windows Electron Entity Framework Fluent Design System Fluid Framework Infer.NET LightGBM Managed Extensibility Framework Microsoft Automatic Graph Layout Microsoft C++ Standard Library Microsoft Cognitive Toolkit Microsoft Design Language Microsoft Detours Microsoft Enterprise Library Microsoft SEAL mimalloc Mixed Reality Toolkit ML.NET mod_mono Mono MonoDevelop MSBuild MsQuic Neural Network Intelligence npm NuGet OneFuzz Open Management Infrastructure Open Neural Network Exchange Open Service Mesh Open XML SDK Orleans Playwright ProcDump ProcMon Python Tools for Visual Studio R Tools for Visual Studio RecursiveExtractor Roslyn Sandcastle SignalR StyleCop SVNBridge T2 Temporal Prover Text Template Transformation Toolkit TLA+ Toolbox U-Prove vcpkg Virtual File System for Git Voldemort VoTT Vowpal Wabbit Windows App SDK Windows Communication Foundation Windows Driver Frameworks KMDF UMDF Windows Forms Windows Presentation Foundation Windows Template Library Windows UI Library WinJS WinObjC WiX XDP for Windows XSP xUnit.net Z3 Theorem Prover
Operating systems	MS-DOS (v1.25, v2.0 & v4.0) Barrelfish SONiC Azure Linux
Other	ChronoZoom Extensible Storage Engine FlexWiki FourQ Gollum Project Mu ReactiveX SILK TLAPS TPM 2.0 Reference Implementation WikiBhasha Windows Subsystem for Linux

Licenses

Forges

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Microsoft Research (MSR)

Main
projects

Languages, compilers	Bartok Bosque Cω F* Lean P Project Verona Phoenix Polyphonic C# SecPAL
Distributed–grid computing	BitVault Confidential Consortium Framework DeepSpeed Orleans
Internet, networking	AjaxView Avalanche Conference XP Gazelle HoneyMonkey Penny Black Wallop WikiBhasha
Other projects	Automatic Graph Layout Cognitive Toolkit Digits Holoportation IllumiRoom Image Composite Editor Infer.NET LightGBM LiveStation MyLifeBits Neural Network Intelligence NodeXL OneFuzz PhotoDNA SEAL SLAM T2 Temporal Prover WorldWide Telescope Z3 Theorem Prover
Operating systems	Barrelfish HomeOS Midori Singularity Verve
APIs	Accelerator Dryad Joins mimalloc
Launched as products	C# Comic Chat Detours F# Sideshow PixelSense (TouchLight) SenseCam ClearType Group Shot Allegiance TrueSkill Songsmith Xbox Kinect

MSR Labs
applied
research

Live Labs

Current	Pivot Seadragon Deep Zoom
Discontinued	Deepfish Listas Live Clipboard Photosynth

FUSE Labs

Other labs

mimalloc

See also

References

Further reading

External links