Implement Memory Pool for Fixed-Size Objects

O(1) Fixed-Size Allocation

General-purpose malloc carries metadata, coalescing, and thread-cache logic. Games, network stacks, and kernels use memory pools when objects are one size and lifetimes are short. PostgreSQL buffer pools and slab allocators in Linux follow the same pattern at different scales.

Pool Design

Preallocate a slab of N objects. Free list threads through objects with an embedded next pointer. Allocate and free are pointer swaps.

c
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Align object size to pointer width for free-list integrity
Pools reduce fragmentation for uniform objects
Thread-local pools avoid atomic contention on global free lists
Fall back to malloc for rare oversized requests

Working Through the Exercise

Keep the relevant documentation open while you implement. When your output disagrees with the reference, trace one failing case by hand before changing random lines.

Trace first: walk one failing input step by step
Read the manual: skim the official doc for the mechanism named in this task
Compare baselines: save measurements from the prior step so speedups are honest

Why for this exercise

You will implement a fixed-size memory pool with allocate and free in O(1). This exercise asks you to beat malloc on a microbenchmark creating many same-sized objects.

Implement memory pool for fixed-size objects with O(1) allocation/deallocation.

Requirements:

Define MemoryPool structure with memory block, free list, metadata
Implement pool_create(size, capacity) to initialize pool
Implement pool_alloc(pool) to allocate block (O(1))
Implement pool_free(pool, ptr) to free block (O(1))
Implement pool_destroy(pool) to cleanup
Track free_count and validate operations
Demonstrate 10-20x speedup over malloc/free
Show usage example with many allocations
Handle out-of-memory condition gracefully
Print pool statistics and comparison

O(1) Fixed-Size Allocation

Pool Design

Preallocate a slab of N objects. Free list threads through objects with an embedded next pointer. Allocate and free are pointer swaps.

c
Loading…

Align object size to pointer width for free-list integrity
Pools reduce fragmentation for uniform objects
Thread-local pools avoid atomic contention on global free lists
Fall back to malloc for rare oversized requests

Working Through the Exercise

Keep the relevant documentation open while you implement. When your output disagrees with the reference, trace one failing case by hand before changing random lines.

Trace first: walk one failing input step by step
Read the manual: skim the official doc for the mechanism named in this task
Compare baselines: save measurements from the prior step so speedups are honest

Why for this exercise

You will implement a fixed-size memory pool with allocate and free in O(1). This exercise asks you to beat malloc on a microbenchmark creating many same-sized objects.

Implement memory pool for fixed-size objects with O(1) allocation/deallocation.

Requirements:

Define MemoryPool structure with memory block, free list, metadata
Implement pool_create(size, capacity) to initialize pool
Implement pool_alloc(pool) to allocate block (O(1))
Implement pool_free(pool, ptr) to free block (O(1))
Implement pool_destroy(pool) to cleanup
Track free_count and validate operations
Demonstrate 10-20x speedup over malloc/free
Show usage example with many allocations
Handle out-of-memory condition gracefully
Print pool statistics and comparison

Topic Overview

O(1) Fixed-Size Allocation

Pool Design

Working Through the Exercise

Why for this exercise

Implementation Task

Progressive Hints

Resources

Open Source

Implement Memory Pool for Fixed-Size Objects

Topic Overview

O(1) Fixed-Size Allocation

Pool Design

Working Through the Exercise

Why for this exercise

Implementation Task

Progressive Hints

Resources

Open Source