trees that track all non-full runs for each bin. Use the red-black
trees to be able to guarantee that each new allocation is placed in the
lowest address available in any non-full run. This change completes the
transition to allocating from low addresses in order to reduce the
retention of sparsely used chunks.
If the run in current use by a bin becomes empty, deallocate the run
rather than retaining it for later use. The previous behavior had the
tendency to spread empty runs across multiple chunks, thus preventing
the release of chunks that were completely unused.
Generalize base_chunk_alloc() (and rename it to base_pages_alloc()) to
handle allocation sizes larger than the chunk size, so that it is
possible to support chunk sizes that are smaller than an arena object.
Reduce the minimum chunk size from 64kB to 8kB.
Optimize tracking of addresses for deleted chunks.
Fix a statistics bug for huge allocations.
eaf8d73212