Custom Allocators

Purpose

Guide agents through memory allocator design and tuning: pool/slab/arena/buddy taxonomy, jemalloc internals and MALLOC_CONF, mimalloc design, tcmalloc thread-caching, writing a simple pool allocator in C, Rust GlobalAlloc trait, fragmentation metrics, and benchmarking.

When to Use

• Replacing malloc for latency-sensitive or embedded workloads
• Tuning jemalloc/mimalloc for server heap behavior
• Implementing arena allocation for request-scoped or frame-based lifetimes
• Writing a Rust custom global allocator for no_std or performance
• Diagnosing heap fragmentation (internal vs external)
• Benchmarking allocator throughput and latency

Workflow

1. Allocator taxonomy