Programs written in C/C++ can suffer from serious memory
fragmentation, leading to low utilization of memory, degraded
performance, and application failure due to memory exhaustion. This
paper introduces Mesh, a plug-in replacement for malloc
that, for the first time, eliminates fragmentation in unmodified
C/C++ applications. Mesh combines novel randomized algorithms with
widely-supported virtual memory operations to provably reduce
fragmentation, breaking the classical Robson bounds with high
probability. Mesh generally matches the runtime performance of
state-of-the-art memory allocators while reducing memory consumption;
in particular, it reduces the memory of consumption of Firefox by 16%
and Redis by 39%.