tlsf
Two-Level Segregated Fit memory allocator implementation.
Written by Matthew Conte ([email protected]).
Released under the BSD license.
Features
- O(1) cost for malloc, free, realloc, memalign
- Extremely low overhead per allocation (4 bytes)
- Low overhead per TLSF management of pools (~3kB)
- Low fragmentation
- Compiles to only a few kB of code and data
- Support for adding and removing memory pool regions on the fly
Caveats
- Currently, assumes architecture can make 4-byte aligned accesses
- Not designed to be thread safe; the user must provide this
Notes
This code was based on the TLSF 1.4 spec and documentation found at:
http://www.gii.upv.es/tlsf/main/docs
It also leverages the TLSF 2.0 improvement to shrink the per-block overhead from 8 to 4 bytes.
History
2016/04/10 - v3.1
- Code moved to github
- tlsfbits.h rolled into tlsf.c
- License changed to BSD
2014/02/08 - v3.0
- This version is based on improvements from 3DInteractive GmbH
- Interface changed to allow more than one memory pool
- Separated pool handling from control structure (adding, removing, debugging)
- Control structure and pools can still be constructed in the same memory block
- Memory blocks for control structure and pools are checked for alignment
- Added functions to retrieve control structure size, alignment size, min and max block size, overhead of pool structure, and overhead of a single allocation
- Minimal Pool size is tlsf_block_size_min() + tlsf_pool_overhead()
- Pool must be empty when it is removed, in order to allow O(1) removal
2011/10/20 - v2.0
- 64-bit support
- More compiler intrinsics for ffs/fls
- ffs/fls verification during TLSF creation in debug builds
2008/04/04 - v1.9
- Add tlsf_heap_check, a heap integrity check
- Support a predefined tlsf_assert macro
- Fix realloc case where block should shrink; if adjacent block is in use, execution would go down the slow path
2007/02/08 - v1.8
- Fix for unnecessary reallocation in tlsf_realloc
2007/02/03 - v1.7
- tlsf_heap_walk takes a callback
- tlsf_realloc now returns NULL on failure
- tlsf_memalign optimization for 4-byte alignment
- Usage of size_t where appropriate
2006/11/21 - v1.6
- ffs/fls broken out into tlsfbits.h
- tlsf_overhead queries per-pool overhead
2006/11/07 - v1.5
- Smart realloc implementation
- Smart memalign implementation
2006/10/11 - v1.4
- Add some ffs/fls implementations
- Minor code footprint reduction
2006/09/14 - v1.3
- Profiling indicates heavy use of blocks of size 1-128, so implement small block handling
- Reduce pool overhead by about 1kb
- Reduce minimum block size from 32 to 12 bytes
- Realloc bug fix
2006/09/09 - v1.2
- Add tlsf_block_size
- Static assertion mechanism for invariants
- Minor bugfixes
2006/09/01 - v1.1
- Add tlsf_realloc
- Add tlsf_walk_heap
2006/08/25 - v1.0