mimalloc
Hacker ApprovedRanked 2 of 4 memory allocators by recommenders
Recommended as a fast, easy drop-in malloc replacement with many tuning knobs, though critics report high memory use.
Recommended as a fast, easy drop-in malloc replacement with many tuning knobs, though critics report high memory use.
29 people gave an opinion
- recommend it
- 22
- criticize it
- 7
- approval share
- 76%
Recommended in 9 of 13 months
- November 2025: recommended
- December 2025: not recommended
- January 2026: recommended
- February 2026: not recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: not recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 22 people recommend itNeeds 10 or more, met.
- 3.1 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 9 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Fast, close to glibc speed
“Switching to mimalloc improved performance by 20x, very close to what glibc offers by default”
Comment from 1 Aug 2026 in “RipGrep musl binaries occasionally segfault during very-large searches” “mimalloc (which is a high performance allocator, at least as fast as the glibc allocator)”
Comment from 28 Aug 2026 in “Don't use musl if you care about performance” “modern allocators like mimalloc or jemalloc easily outperformed modern GCs of Java”
Comment from 17 Nov 2025 in “Garbage collection is useful” - Comment from 16 Mar 2026 in “Jemalloc un-abandoned by Meta”
- Comment from 29 Oct 2026 in “noalloc: Tooling and libraries to enforce zero heap allocations in Golang”
Easy drop-in replacement, no code changes
“Luckily that one is fairly easy to fix with installing mimalloc and deploying the hijack dll”
Comment from 28 Sep 2026 in “Writing Efficient C++ Code (2013)” “plugging in mimalloc or jemalloc will be much less work, and much less error prone”
Comment from 19 Sep 2026 in “What Zig felt like, coming from Rust” “Mi-malloc is the better choice if you must preload a library”
Comment from 1 Jan 2026 in “Memory Subsystem Optimizations” - Comment from 27 Sep 2026 in “Writing Efficient C++ Code (2013)”
Aggressive memory reclaim, stable footprint
“Dip's memory, using mimalloc, stabilizes at ~60 MB post request completion no matter how many requests you throw at it.”
Comment from 28 Oct 2026 in “Four Months of Zig” “Agree with you on mimalloc. It can even be configured to be aggressive in memory reclaim at the cost of performance.”
Comment from 1 Aug 2026 in “RipGrep musl binaries occasionally segfault during very-large searches” “mimalloc aggressively reclaims space and it benefits the use case in our Dip database built on rust.”
Comment from 27 Oct 2026 in “Four Months of Zig” Many configurable knobs
“Agree with you on mimalloc. It can even be configured to be aggressive in memory reclaim at the cost of performance.”
Comment from 1 Aug 2026 in “RipGrep musl binaries occasionally segfault during very-large searches” “The nice thing about mimalloc is that there are a ton of configurable knobs available via env vars.”
Comment from 16 Mar 2026 in “Jemalloc un-abandoned by Meta”
What people warn about
Each mark is one comment
Uses more memory than expected
“we had problem with mimalloc memory usage with pthread enabled”
Comment from 20 Dec 2025 in “OpenSCAD is kinda neat” “the additional memory usage was a very real inconvenience”
Comment from 1 Aug 2026 in “RipGrep musl binaries occasionally segfault during very-large searches” “mimalloc just consumed memory like crazy”
Comment from 17 Mar 2026 in “Jemalloc un-abandoned by Meta” - Comment from 18 Sep 2026 in “Comparison of Malloc() Algorithms”
- Comment from 18 Sep 2026 in “Comparison of Malloc() Algorithms”
Speed claims did not hold up
“Last time I checked mimalloc which was admittedly a while ago, probably 5 years, it was noticebly worse”
Comment from 16 Mar 2026 in “Jemalloc un-abandoned by Meta” “mimalloc definitely made claims that could not be reproduced”
Comment from 16 Mar 2026 in “Jemalloc un-abandoned by Meta” “it wasn't faster by much, and had pretty bad worst cases”
Comment from 16 Mar 2026 in “Jemalloc un-abandoned by Meta” - Comment from 16 Mar 2026 in “Jemalloc un-abandoned by Meta”
Seen as a black box
“big general-purpose allocators like jemalloc or mimalloc are usually a bandaid to somewhat salvage a failed memory management strategy”
Comment from 13 Jun 2026 in “Orthodox C++” “Standard options like jemalloc and mimalloc are incredibly fast, but they act as black boxes.”
Comment from 25 Mar 2026 in “A single-file C allocator with explicit heaps and tuning knobs”
Other memory allocators people recommend
The three most recommended other memory allocators, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| jemalloc | 34 | 11 | 76% | 6 | 8 yrs3 owners | Approved |
| mimallocThis page | 22 | 7 | 76% | 9 | — | Approved |
| Bumpalo Rust crate | 8 | 2 | 80% | 5 | — | — |
| tcmalloc | 7 | 4 | 64% | 4 | — | — |
What people said
36 of the 38 comments that mention it, newest first. Each links to the original comment.
“mimalloc does just as good as bumpalo (within 5%)”
“Dip's memory, using mimalloc, stabilizes at ~60 MB post request completion no matter how many requests you throw at it.”
“mimalloc aggressively reclaims space and it benefits the use case in our Dip database built on rust.”
“Luckily that one is fairly easy to fix with installing mimalloc and deploying the hijack dll”
“installing mimalloc and deploying the hijack dll”
“plugging in mimalloc or jemalloc will be much less work, and much less error prone”
“required more cpu and memory”
“but required more cpu and memory”
“musl without mimalloc has a 144% overhead”
“mimalloc (which is a high performance allocator, at least as fast as the glibc allocator)”
“use some tool like mimalloc”
“We use musl+mimalloc by default for our entire production operating systems”
“Agree with you on mimalloc. It can even be configured to be aggressive in memory reclaim at the cost of performance.”
“the additional memory usage was a very real inconvenience”
“Switching to mimalloc improved performance by 20x, very close to what glibc offers by default”
“mimalloc arenas are slightly better for this”
“Take a look at https://github.com/microsoft/mimalloc”
“big general-purpose allocators like jemalloc or mimalloc are usually a bandaid to somewhat salvage a failed memory management strategy”
“using MS's mimalloc to run zenlisp under OpenBSD because the core malloc will just tell good try”
“Standard options like jemalloc and mimalloc are incredibly fast, but they act as black boxes.”
“mimalloc just consumed memory like crazy”
“a simple allocator with one bitmap-tracked pool per allocation size”
“older mimalloc from default rust crate would cause memory corruption with large allocations >2Gb in about 5% of the cases”
“mimalloc definitely made claims that could not be reproduced”
“it wasn't faster by much, and had pretty bad worst cases”
“it was marketed as small/simple/consistent with an opt-in high-severity mode”
“that didn't hold up to real world testing”
“mimalloc 2.2.4: 173,240 KB, 280 ms”
“Mimalloc v3 has just come out (about a month ago) and is a significant improvement over both v2 and v1”
“The nice thing about mimalloc is that there are a ton of configurable knobs available via env vars.”
“I used mimalloc to run zenlisp under OpenBSD as it would clash with the paranoid malloc of base.”
“Last time I checked mimalloc which was admittedly a while ago, probably 5 years, it was noticebly worse”
“The performance gains are significant (around 20%).”
“Mi-malloc is the better choice if you must preload a library”
“we had problem with mimalloc memory usage with pthread enabled”
“modern allocators like mimalloc or jemalloc easily outperformed modern GCs of Java”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.