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tlsf/README.md
2016-04-11 16:54:46 -07:00

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# tlsf
Two-Level Segregated Fit memory allocator implementation.
Written by Matthew Conte (matt@baisoku.org).
Released under the BSD license.
Features
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* 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
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* 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
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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
* First release