Minimal Memory Allocator in C

This project presents a simple custom memory allocator written in C, mirroring functions like malloc, calloc, realloc, and free. It uses sbrk for small memory requests and mmap for larger allocations, aiming to optimize memory management by reducing fragmentation through block splitting and merging adjacent free blocks. Note that this allocator is not thread-safe; simultaneous calls to its functions may lead to unpredictable behavior. A detailed blog post explaining the development process is available for those interested.

Building this allocator requires a POSIX-compatible system (Linux or macOS), GCC, and Make, but it’s incompatible with Windows due to reliance on sbrk and mmap. To compile, run “make” to build the project, “make tests” for functionality checks, and “make bench” for performance benchmarking.

To incorporate this library in your code, build the static library using “make lib,” include the header file, and compile your program with the library flags. An example program demonstrates basic usage: initializing an array with malloc, resizing with realloc, and freeing memory with free.

The project structure includes source files, headers, testing scripts, and examples. The author clarifies that the allocator is not suitable for multithreaded environments and mentions that sbrk is deprecated on macOS but still operational. No mechanisms for defragmentation or memory compaction are provided.

This project is open-source under the MIT License, and contributions are welcome. Acknowledgements go to Dan Luu for his helpful malloc tutorial, which served as a learning reference, and to colleagues for reviewing the related blog post.

In summary, this minimal memory allocator offers a straightforward approach to managing memory efficiently in C, suitable for learning and small projects while highlighting the challenges of manual memory management.

FAQs:

Q: Is this memory allocator suitable for multithreaded applications?
A: No, it is not thread-safe and does not include mutex protections.

Q: Why does the project use sbrk and mmap?
A: sbrk manages small allocations, while mmap handles large requests, to optimize memory handling.

Q: Can I customize or extend this allocator?
A: Yes, contributions are encouraged; you can modify or improve its features.

Q: Is it compatible with Windows?
A: No, because it relies on POSIX-specific functions that are not supported on Windows.

Q: Does it have defragmentation capabilities?
A: No, it does not support memory defragmentation or compaction.