A simple explicit allocator package based on implicit list.
It's an application for learning about Virtual Memory and Dynamic memory Allocation.
A dynamic memory allocator maintains an area of a process's virtual memory known as heap. It's used to acquire additional virtual memory at run time.
- Block format
- A block consists of a one-word header, the payload, possibly some additional padding and a one-word boundary-tag (footer). The minimum block size is 16 bytes. The header encodes the block size as well as whether the block is allocated or not.
- Free list format
- The allocator maintains an implicit free list to keep track of free blocks. The first word of the free list is an unused padding word aligned to a double-word boundary. The padding is followed by a special 8-bytes-allocated prologue block, followed by a zero or more regular blocks that are created by calls to malloc or free. The heap always ends with a special epilogue block, which is a zero-size allocated block that consists of only a header.
- Placement policy
- The allocator searches the free list for a free block that is large enough to hold the requested block using Next fit algorithm.
- Splitting policy
- After placing the requested block in some free block, The allocator splits the block if the remainder would be equal to or greater than the minimum block size.
- Coalescing policy
- The allocator uses immediate boundary-tag coalescing, that it merges next and previous free blocks with the current block each time an applications calls free() on this current block.
mm.{c,h}: The package implementationmemlib.{c,h}: A module that simulates the memory system
- The project helped me understand different memory allocation techniques and how memory allocators work.
- I learned about virtual memory, and how virtual memory is mapped to physical memory (Address Translation).