The SLOB (Simple List Of Blocks) allocator is one of three available memory allocators in the Linux kernel. (The other two are SLAB and SLUB). The SLOB allocator is designed to be a small and efficient allocation framework for use in small systems such as embedded systems. Unfortunately, a major limitation of the SLOB allocator is that it suffers greatly from internal fragmentation.
SLOB currently uses a first-fit algorithm, which uses the first available space for memory. Recently a reply from Linus Torvalds on a Linux mailing list[1] were made where he suggested the use of a best-fit algorithm, which tries to find a memory block which suits needs best. Best fit finds the smallest space which fits the required amount available, avoiding loss of performance, both by fragmentation and consolidation of memory.
By default, Linux kernel uses a SLAB Allocation system, and when the CONFIG_SLAB flag is disabled, the kernel falls back to using the 'SLOB' allocator[2]. The SLOB allocator was used in DSLinux on Nintendo DS handheld console.