jemalloc 4.2.0 released

Jason Evans jasone at
Thu May 12 21:25:54 PDT 2016

jemalloc 4.2.0 is now available.

New features:
- Add the arena.<i>.reset mallctl, which makes it possible to discard all of an arena's allocations in a single operation. (@jasone)
- Add the stats.retained and stats.arenas.<i>.retained statistics. (@jasone)
- Add the --with-version configure option. (@jasone)
- Support --with-lg-page values larger than actual page size. (@jasone)

- Use pairing heaps rather than red-black trees for various hot data structures. (@djwatson, @jasone)
- Streamline fast paths of rtree operations. (@jasone)
- Optimize the fast paths of calloc() and [m,d,sd]allocx(). (@jasone)
- Decommit unused virtual memory if the OS does not overcommit. (@jasone)
- Specify MAP_NORESERVE on Linux if [heuristic] overcommit is active, in order to avoid unfortunate interactions during fork(2). (@jasone)

Bug fixes:
- Fix chunk accounting related to triggering gdump profiles. (@jasone)
- Link against librt for clock_gettime(2) if glibc < 2.17. (@jasone)
- Scale leak report summary according to sampling probability. (@jasone)

For the complete ChangeLog, see:

Direct download:

Starting point for general information:

Browsable revision history:

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