I remember hearing about a server program that worked around this problem by creating two memory arenas. All allocations came from, say, arena A until it was full, then they came from arena B. That’s the whole strategy. Things were still deallocated normally. The basic idea was that by the time arena B was full, everything in arena A would have been cleaned up normally and the memory allocator would have coalesced adjacent free memory; in other words, the strategy was to guarantee the allocator had a chance to clean up fragmentation (usually the allocator doesn’t need the help, but this approach guaranteed correct behavior as long as everything was eventually cleaned up; i.e., there were no classic leaks).