Jemalloc upgraded to version 5.0.1.

1 files changed, 595 insertions, 1 deletions

diff --git a/deps/jemalloc/ChangeLog b/deps/jemalloc/ChangeLog
index e3b0a5190..29a00fb78 100644
--- a/deps/jemalloc/ChangeLog
+++ b/deps/jemalloc/ChangeLog
@@ -4,6 +4,600 @@ brevity.  Much more detail can be found in the git revision history:
 
     https://github.com/jemalloc/jemalloc
 
+* 5.1.0 (May 4th, 2018)
+
+  This release is primarily about fine-tuning, ranging from several new features
+  to numerous notable performance and portability enhancements.  The release and
+  prior dev versions have been running in multiple large scale applications for
+  months, and the cumulative improvements are substantial in many cases.
+
+  Given the long and successful production runs, this release is likely a good
+  candidate for applications to upgrade, from both jemalloc 5.0 and before.  For
+  performance-critical applications, the newly added TUNING.md provides
+  guidelines on jemalloc tuning.
+
+  New features:
+  - Implement transparent huge page support for internal metadata.  (@interwq)
+  - Add opt.thp to allow enabling / disabling transparent huge pages for all
+    mappings.  (@interwq)
+  - Add maximum background thread count option.  (@djwatson)
+  - Allow prof_active to control opt.lg_prof_interval and prof.gdump.
+    (@interwq)
+  - Allow arena index lookup based on allocation addresses via mallctl.
+    (@lionkov)
+  - Allow disabling initial-exec TLS model.  (@davidtgoldblatt, @KenMacD)
+  - Add opt.lg_extent_max_active_fit to set the max ratio between the size of
+    the active extent selected (to split off from) and the size of the requested
+    allocation.  (@interwq, @davidtgoldblatt)
+  - Add retain_grow_limit to set the max size when growing virtual address
+    space.  (@interwq)
+  - Add mallctl interfaces:
+    + arena.<i>.retain_grow_limit  (@interwq)
+    + arenas.lookup  (@lionkov)
+    + max_background_threads  (@djwatson)
+    + opt.lg_extent_max_active_fit  (@interwq)
+    + opt.max_background_threads  (@djwatson)
+    + opt.metadata_thp  (@interwq)
+    + opt.thp  (@interwq)
+    + stats.metadata_thp  (@interwq)
+
+  Portability improvements:
+  - Support GNU/kFreeBSD configuration.  (@paravoid)
+  - Support m68k, nios2 and SH3 architectures.  (@paravoid)
+  - Fall back to FD_CLOEXEC when O_CLOEXEC is unavailable.  (@zonyitoo)
+  - Fix symbol listing for cross-compiling.  (@tamird)
+  - Fix high bits computation on ARM.  (@davidtgoldblatt, @paravoid)
+  - Disable the CPU_SPINWAIT macro for Power.  (@davidtgoldblatt, @marxin)
+  - Fix MSVC 2015 & 2017 builds.  (@rustyx)
+  - Improve RISC-V support.  (@EdSchouten)
+  - Set name mangling script in strict mode.  (@nicolov)
+  - Avoid MADV_HUGEPAGE on ARM.  (@marxin)
+  - Modify configure to determine return value of strerror_r.
+    (@davidtgoldblatt, @cferris1000)
+  - Make sure CXXFLAGS is tested with CPP compiler.  (@nehaljwani)
+  - Fix 32-bit build on MSVC.  (@rustyx)
+  - Fix external symbol on MSVC.  (@maksqwe)
+  - Avoid a printf format specifier warning.  (@jasone)
+  - Add configure option --disable-initial-exec-tls which can allow jemalloc to
+    be dynamically loaded after program startup.  (@davidtgoldblatt, @KenMacD)
+  - AArch64: Add ILP32 support.  (@cmuellner)
+  - Add --with-lg-vaddr configure option to support cross compiling.
+    (@cmuellner, @davidtgoldblatt)
+
+  Optimizations and refactors:
+  - Improve active extent fit with extent_max_active_fit.  This considerably
+    reduces fragmentation over time and improves virtual memory and metadata
+    usage.  (@davidtgoldblatt, @interwq)
+  - Eagerly coalesce large extents to reduce fragmentation.  (@interwq)
+  - sdallocx: only read size info when page aligned (i.e. possibly sampled),
+    which speeds up the sized deallocation path significantly.  (@interwq)
+  - Avoid attempting new mappings for in place expansion with retain, since
+    it rarely succeeds in practice and causes high overhead.  (@interwq)
+  - Refactor OOM handling in newImpl.  (@wqfish)
+  - Add internal fine-grained logging functionality for debugging use.
+    (@davidtgoldblatt)
+  - Refactor arena / tcache interactions.  (@davidtgoldblatt)
+  - Refactor extent management with dumpable flag.  (@davidtgoldblatt)
+  - Add runtime detection of lazy purging.  (@interwq)
+  - Use pairing heap instead of red-black tree for extents_avail.  (@djwatson)
+  - Use sysctl on startup in FreeBSD.  (@trasz)
+  - Use thread local prng state instead of atomic.  (@djwatson)
+  - Make decay to always purge one more extent than before, because in
+    practice large extents are usually the ones that cross the decay threshold.
+    Purging the additional extent helps save memory as well as reduce VM
+    fragmentation.  (@interwq)
+  - Fast division by dynamic values.  (@davidtgoldblatt)
+  - Improve the fit for aligned allocation.  (@interwq, @edwinsmith)
+  - Refactor extent_t bitpacking.  (@rkmisra)
+  - Optimize the generated assembly for ticker operations.  (@davidtgoldblatt)
+  - Convert stats printing to use a structured text emitter.  (@davidtgoldblatt)
+  - Remove preserve_lru feature for extents management.  (@djwatson)
+  - Consolidate two memory loads into one on the fast deallocation path.
+    (@davidtgoldblatt, @interwq)
+
+  Bug fixes (most of the issues are only relevant to jemalloc 5.0):
+  - Fix deadlock with multithreaded fork in OS X.  (@davidtgoldblatt)
+  - Validate returned file descriptor before use.  (@zonyitoo)
+  - Fix a few background thread initialization and shutdown issues.  (@interwq)
+  - Fix an extent coalesce + decay race by taking both coalescing extents off
+    the LRU list.  (@interwq)
+  - Fix potentially unbound increase during decay, caused by one thread keep
+    stashing memory to purge while other threads generating new pages.  The
+    number of pages to purge is checked to prevent this.  (@interwq)
+  - Fix a FreeBSD bootstrap assertion.  (@strejda, @interwq)
+  - Handle 32 bit mutex counters.  (@rkmisra)
+  - Fix a indexing bug when creating background threads.  (@davidtgoldblatt,
+    @binliu19)
+  - Fix arguments passed to extent_init.  (@yuleniwo, @interwq)
+  - Fix addresses used for ordering mutexes.  (@rkmisra)
+  - Fix abort_conf processing during bootstrap.  (@interwq)
+  - Fix include path order for out-of-tree builds.  (@cmuellner)
+
+  Incompatible changes:
+  - Remove --disable-thp.  (@interwq)
+  - Remove mallctl interfaces:
+    + config.thp  (@interwq)
+
+  Documentation:
+  - Add TUNING.md.  (@interwq, @davidtgoldblatt, @djwatson)
+
+* 5.0.1 (July 1, 2017)
+
+  This bugfix release fixes several issues, most of which are obscure enough
+  that typical applications are not impacted.
+
+  Bug fixes:
+  - Update decay->nunpurged before purging, in order to avoid potential update
+    races and subsequent incorrect purging volume.  (@interwq)
+  - Only abort on dlsym(3) error if the failure impacts an enabled feature (lazy
+    locking and/or background threads).  This mitigates an initialization
+    failure bug for which we still do not have a clear reproduction test case.
+    (@interwq)
+  - Modify tsd management so that it neither crashes nor leaks if a thread's
+    only allocation activity is to call free() after TLS destructors have been
+    executed.  This behavior was observed when operating with GNU libc, and is
+    unlikely to be an issue with other libc implementations.  (@interwq)
+  - Mask signals during background thread creation.  This prevents signals from
+    being inadvertently delivered to background threads.  (@jasone,
+    @davidtgoldblatt, @interwq)
+  - Avoid inactivity checks within background threads, in order to prevent
+    recursive mutex acquisition.  (@interwq)
+  - Fix extent_grow_retained() to use the specified hooks when the
+    arena.<i>.extent_hooks mallctl is used to override the default hooks.
+    (@interwq)
+  - Add missing reentrancy support for custom extent hooks which allocate.
+    (@interwq)
+  - Post-fork(2), re-initialize the list of tcaches associated with each arena
+    to contain no tcaches except the forking thread's.  (@interwq)
+  - Add missing post-fork(2) mutex reinitialization for extent_grow_mtx.  This
+    fixes potential deadlocks after fork(2).  (@interwq)
+  - Enforce minimum autoconf version (currently 2.68), since 2.63 is known to
+    generate corrupt configure scripts.  (@jasone)
+  - Ensure that the configured page size (--with-lg-page) is no larger than the
+    configured huge page size (--with-lg-hugepage).  (@jasone)
+
+* 5.0.0 (June 13, 2017)
+
+  Unlike all previous jemalloc releases, this release does not use naturally
+  aligned "chunks" for virtual memory management, and instead uses page-aligned
+  "extents".  This change has few externally visible effects, but the internal
+  impacts are... extensive.  Many other internal changes combine to make this
+  the most cohesively designed version of jemalloc so far, with ample
+  opportunity for further enhancements.
+
+  Continuous integration is now an integral aspect of development thanks to the
+  efforts of @davidtgoldblatt, and the dev branch tends to remain reasonably
+  stable on the tested platforms (Linux, FreeBSD, macOS, and Windows).  As a
+  side effect the official release frequency may decrease over time.
+
+  New features:
+  - Implement optional per-CPU arena support; threads choose which arena to use
+    based on current CPU rather than on fixed thread-->arena associations.
+    (@interwq)
+  - Implement two-phase decay of unused dirty pages.  Pages transition from
+    dirty-->muzzy-->clean, where the first phase transition relies on
+    madvise(... MADV_FREE) semantics, and the second phase transition discards
+    pages such that they are replaced with demand-zeroed pages on next access.
+    (@jasone)
+  - Increase decay time resolution from seconds to milliseconds.  (@jasone)
+  - Implement opt-in per CPU background threads, and use them for asynchronous
+    decay-driven unused dirty page purging.  (@interwq)
+  - Add mutex profiling, which collects a variety of statistics useful for
+    diagnosing overhead/contention issues.  (@interwq)
+  - Add C++ new/delete operator bindings.  (@djwatson)
+  - Support manually created arena destruction, such that all data and metadata
+    are discarded.  Add MALLCTL_ARENAS_DESTROYED for accessing merged stats
+    associated with destroyed arenas.  (@jasone)
+  - Add MALLCTL_ARENAS_ALL as a fixed index for use in accessing
+    merged/destroyed arena statistics via mallctl.  (@jasone)
+  - Add opt.abort_conf to optionally abort if invalid configuration options are
+    detected during initialization.  (@interwq)
+  - Add opt.stats_print_opts, so that e.g. JSON output can be selected for the
+    stats dumped during exit if opt.stats_print is true.  (@jasone)
+  - Add --with-version=VERSION for use when embedding jemalloc into another
+    project's git repository.  (@jasone)
+  - Add --disable-thp to support cross compiling.  (@jasone)
+  - Add --with-lg-hugepage to support cross compiling.  (@jasone)
+  - Add mallctl interfaces (various authors):
+    + background_thread
+    + opt.abort_conf
+    + opt.retain
+    + opt.percpu_arena
+    + opt.background_thread
+    + opt.{dirty,muzzy}_decay_ms
+    + opt.stats_print_opts
+    + arena.<i>.initialized
+    + arena.<i>.destroy
+    + arena.<i>.{dirty,muzzy}_decay_ms
+    + arena.<i>.extent_hooks
+    + arenas.{dirty,muzzy}_decay_ms
+    + arenas.bin.<i>.slab_size
+    + arenas.nlextents
+    + arenas.lextent.<i>.size
+    + arenas.create
+    + stats.background_thread.{num_threads,num_runs,run_interval}
+    + stats.mutexes.{ctl,background_thread,prof,reset}.
+      {num_ops,num_spin_acq,num_wait,max_wait_time,total_wait_time,max_num_thds,
+      num_owner_switch}
+    + stats.arenas.<i>.{dirty,muzzy}_decay_ms
+    + stats.arenas.<i>.uptime
+    + stats.arenas.<i>.{pmuzzy,base,internal,resident}
+    + stats.arenas.<i>.{dirty,muzzy}_{npurge,nmadvise,purged}
+    + stats.arenas.<i>.bins.<j>.{nslabs,reslabs,curslabs}
+    + stats.arenas.<i>.bins.<j>.mutex.
+      {num_ops,num_spin_acq,num_wait,max_wait_time,total_wait_time,max_num_thds,
+      num_owner_switch}
+    + stats.arenas.<i>.lextents.<j>.{nmalloc,ndalloc,nrequests,curlextents}
+    + stats.arenas.i.mutexes.{large,extent_avail,extents_dirty,extents_muzzy,
+      extents_retained,decay_dirty,decay_muzzy,base,tcache_list}.
+      {num_ops,num_spin_acq,num_wait,max_wait_time,total_wait_time,max_num_thds,
+      num_owner_switch}
+
+  Portability improvements:
+  - Improve reentrant allocation support, such that deadlock is less likely if
+    e.g. a system library call in turn allocates memory.  (@davidtgoldblatt,
+    @interwq)
+  - Support static linking of jemalloc with glibc.  (@djwatson)
+
+  Optimizations and refactors:
+  - Organize virtual memory as "extents" of virtual memory pages, rather than as
+    naturally aligned "chunks", and store all metadata in arbitrarily distant
+    locations.  This reduces virtual memory external fragmentation, and will
+    interact better with huge pages (not yet explicitly supported).  (@jasone)
+  - Fold large and huge size classes together; only small and large size classes
+    remain.  (@jasone)
+  - Unify the allocation paths, and merge most fast-path branching decisions.
+    (@davidtgoldblatt, @interwq)
+  - Embed per thread automatic tcache into thread-specific data, which reduces
+    conditional branches and dereferences.  Also reorganize tcache to increase
+    fast-path data locality.  (@interwq)
+  - Rewrite atomics to closely model the C11 API, convert various
+    synchronization from mutex-based to atomic, and use the explicit memory
+    ordering control to resolve various hypothetical races without increasing
+    synchronization overhead.  (@davidtgoldblatt)
+  - Extensively optimize rtree via various methods:
+    + Add multiple layers of rtree lookup caching, since rtree lookups are now
+      part of fast-path deallocation.  (@interwq)
+    + Determine rtree layout at compile time.  (@jasone)
+    + Make the tree shallower for common configurations.  (@jasone)
+    + Embed the root node in the top-level rtree data structure, thus avoiding
+      one level of indirection.  (@jasone)
+    + Further specialize leaf elements as compared to internal node elements,
+      and directly embed extent metadata needed for fast-path deallocation.
+      (@jasone)
+    + Ignore leading always-zero address bits (architecture-specific).
+      (@jasone)
+  - Reorganize headers (ongoing work) to make them hermetic, and disentangle
+    various module dependencies.  (@davidtgoldblatt)
+  - Convert various internal data structures such as size class metadata from
+    boot-time-initialized to compile-time-initialized.  Propagate resulting data
+    structure simplifications, such as making arena metadata fixed-size.
+    (@jasone)
+  - Simplify size class lookups when constrained to size classes that are
+    multiples of the page size.  This speeds lookups, but the primary benefit is
+    complexity reduction in code that was the source of numerous regressions.
+    (@jasone)
+  - Lock individual extents when possible for localized extent operations,
+    rather than relying on a top-level arena lock.  (@davidtgoldblatt, @jasone)
+  - Use first fit layout policy instead of best fit, in order to improve
+    packing.  (@jasone)
+  - If munmap(2) is not in use, use an exponential series to grow each arena's
+    virtual memory, so that the number of disjoint virtual memory mappings
+    remains low.  (@jasone)
+  - Implement per arena base allocators, so that arenas never share any virtual
+    memory pages.  (@jasone)
+  - Automatically generate private symbol name mangling macros.  (@jasone)
+
+  Incompatible changes:
+  - Replace chunk hooks with an expanded/normalized set of extent hooks.
+    (@jasone)
+  - Remove ratio-based purging.  (@jasone)
+  - Remove --disable-tcache.  (@jasone)
+  - Remove --disable-tls.  (@jasone)
+  - Remove --enable-ivsalloc.  (@jasone)
+  - Remove --with-lg-size-class-group.  (@jasone)
+  - Remove --with-lg-tiny-min.  (@jasone)
+  - Remove --disable-cc-silence.  (@jasone)
+  - Remove --enable-code-coverage.  (@jasone)
+  - Remove --disable-munmap (replaced by opt.retain).  (@jasone)
+  - Remove Valgrind support.  (@jasone)
+  - Remove quarantine support.  (@jasone)
+  - Remove redzone support.  (@jasone)
+  - Remove mallctl interfaces (various authors):
+    + config.munmap
+    + config.tcache
+    + config.tls
+    + config.valgrind
+    + opt.lg_chunk
+    + opt.purge
+    + opt.lg_dirty_mult
+    + opt.decay_time
+    + opt.quarantine
+    + opt.redzone
+    + opt.thp
+    + arena.<i>.lg_dirty_mult
+    + arena.<i>.decay_time
+    + arena.<i>.chunk_hooks
+    + arenas.initialized
+    + arenas.lg_dirty_mult
+    + arenas.decay_time
+    + arenas.bin.<i>.run_size
+    + arenas.nlruns
+    + arenas.lrun.<i>.size
+    + arenas.nhchunks
+    + arenas.hchunk.<i>.size
+    + arenas.extend
+    + stats.cactive
+    + stats.arenas.<i>.lg_dirty_mult
+    + stats.arenas.<i>.decay_time
+    + stats.arenas.<i>.metadata.{mapped,allocated}
+    + stats.arenas.<i>.{npurge,nmadvise,purged}
+    + stats.arenas.<i>.huge.{allocated,nmalloc,ndalloc,nrequests}
+    + stats.arenas.<i>.bins.<j>.{nruns,reruns,curruns}
+    + stats.arenas.<i>.lruns.<j>.{nmalloc,ndalloc,nrequests,curruns}
+    + stats.arenas.<i>.hchunks.<j>.{nmalloc,ndalloc,nrequests,curhchunks}
+
+  Bug fixes:
+  - Improve interval-based profile dump triggering to dump only one profile when
+    a single allocation's size exceeds the interval.  (@jasone)
+  - Use prefixed function names (as controlled by --with-jemalloc-prefix) when
+    pruning backtrace frames in jeprof.  (@jasone)
+
+* 4.5.0 (February 28, 2017)
+
+  This is the first release to benefit from much broader continuous integration
+  testing, thanks to @davidtgoldblatt.  Had we had this testing infrastructure
+  in place for prior releases, it would have caught all of the most serious
+  regressions fixed by this release.
+
+  New features:
+  - Add --disable-thp and the opt.thp mallctl to provide opt-out mechanisms for
+    transparent huge page integration.  (@jasone)
+  - Update zone allocator integration to work with macOS 10.12.  (@glandium)
+  - Restructure *CFLAGS configuration, so that CFLAGS behaves typically, and
+    EXTRA_CFLAGS provides a way to specify e.g. -Werror during building, but not
+    during configuration.  (@jasone, @ronawho)
+
+  Bug fixes:
+  - Fix DSS (sbrk(2)-based) allocation.  This regression was first released in
+    4.3.0.  (@jasone)
+  - Handle race in per size class utilization computation.  This functionality
+    was first released in 4.0.0.  (@interwq)
+  - Fix lock order reversal during gdump.  (@jasone)
+  - Fix/refactor tcache synchronization.  This regression was first released in
+    4.0.0.  (@jasone)
+  - Fix various JSON-formatted malloc_stats_print() bugs.  This functionality
+    was first released in 4.3.0.  (@jasone)
+  - Fix huge-aligned allocation.  This regression was first released in 4.4.0.
+    (@jasone)
+  - When transparent huge page integration is enabled, detect what state pages
+    start in according to the kernel's current operating mode, and only convert
+    arena chunks to non-huge during purging if that is not their initial state.
+    This functionality was first released in 4.4.0.  (@jasone)
+  - Fix lg_chunk clamping for the --enable-cache-oblivious --disable-fill case.
+    This regression was first released in 4.0.0.  (@jasone, @428desmo)
+  - Properly detect sparc64 when building for Linux.  (@glaubitz)
+
+* 4.4.0 (December 3, 2016)
+
+  New features:
+  - Add configure support for *-*-linux-android.  (@cferris1000, @jasone)
+  - Add the --disable-syscall configure option, for use on systems that place
+    security-motivated limitations on syscall(2).  (@jasone)
+  - Add support for Debian GNU/kFreeBSD.  (@thesam)
+
+  Optimizations:
+  - Add extent serial numbers and use them where appropriate as a sort key that
+    is higher priority than address, so that the allocation policy prefers older
+    extents.  This tends to improve locality (decrease fragmentation) when
+    memory grows downward.  (@jasone)
+  - Refactor madvise(2) configuration so that MADV_FREE is detected and utilized
+    on Linux 4.5 and newer.  (@jasone)
+  - Mark partially purged arena chunks as non-huge-page.  This improves
+    interaction with Linux's transparent huge page functionality.  (@jasone)
+
+  Bug fixes:
+  - Fix size class computations for edge conditions involving extremely large
+    allocations.  This regression was first released in 4.0.0.  (@jasone,
+    @ingvarha)
+  - Remove overly restrictive assertions related to the cactive statistic.  This
+    regression was first released in 4.1.0.  (@jasone)
+  - Implement a more reliable detection scheme for os_unfair_lock on macOS.
+    (@jszakmeister)
+
+* 4.3.1 (November 7, 2016)
+
+  Bug fixes:
+  - Fix a severe virtual memory leak.  This regression was first released in
+    4.3.0.  (@interwq, @jasone)
+  - Refactor atomic and prng APIs to restore support for 32-bit platforms that
+    use pre-C11 toolchains, e.g. FreeBSD's mips.  (@jasone)
+
+* 4.3.0 (November 4, 2016)
+
+  This is the first release that passes the test suite for multiple Windows
+  configurations, thanks in large part to @glandium setting up continuous
+  integration via AppVeyor (and Travis CI for Linux and OS X).
+
+  New features:
+  - Add "J" (JSON) support to malloc_stats_print().  (@jasone)
+  - Add Cray compiler support.  (@ronawho)
+
+  Optimizations:
+  - Add/use adaptive spinning for bootstrapping and radix tree node
+    initialization.  (@jasone)
+
+  Bug fixes:
+  - Fix large allocation to search starting in the optimal size class heap,
+    which can substantially reduce virtual memory churn and fragmentation.  This
+    regression was first released in 4.0.0.  (@mjp41, @jasone)
+  - Fix stats.arenas.<i>.nthreads accounting.  (@interwq)
+  - Fix and simplify decay-based purging.  (@jasone)
+  - Make DSS (sbrk(2)-related) operations lockless, which resolves potential
+    deadlocks during thread exit.  (@jasone)
+  - Fix over-sized allocation of radix tree leaf nodes.  (@mjp41, @ogaun,
+    @jasone)
+  - Fix over-sized allocation of arena_t (plus associated stats) data
+    structures.  (@jasone, @interwq)
+  - Fix EXTRA_CFLAGS to not affect configuration.  (@jasone)
+  - Fix a Valgrind integration bug.  (@ronawho)
+  - Disallow 0x5a junk filling when running in Valgrind.  (@jasone)
+  - Fix a file descriptor leak on Linux.  This regression was first released in
+    4.2.0.  (@vsarunas, @jasone)
+  - Fix static linking of jemalloc with glibc.  (@djwatson)
+  - Use syscall(2) rather than {open,read,close}(2) during boot on Linux.  This
+    works around other libraries' system call wrappers performing reentrant
+    allocation.  (@kspinka, @Whissi, @jasone)
+  - Fix OS X default zone replacement to work with OS X 10.12.  (@glandium,
+    @jasone)
+  - Fix cached memory management to avoid needless commit/decommit operations
+    during purging, which resolves permanent virtual memory map fragmentation
+    issues on Windows.  (@mjp41, @jasone)
+  - Fix TSD fetches to avoid (recursive) allocation.  This is relevant to
+    non-TLS and Windows configurations.  (@jasone)
+  - Fix malloc_conf overriding to work on Windows.  (@jasone)
+  - Forcibly disable lazy-lock on Windows (was forcibly *enabled*).  (@jasone)
+
+* 4.2.1 (June 8, 2016)
+
+  Bug fixes:
+  - Fix bootstrapping issues for configurations that require allocation during
+    tsd initialization (e.g. --disable-tls).  (@cferris1000, @jasone)
+  - Fix gettimeofday() version of nstime_update().  (@ronawho)
+  - Fix Valgrind regressions in calloc() and chunk_alloc_wrapper().  (@ronawho)
+  - Fix potential VM map fragmentation regression.  (@jasone)
+  - Fix opt_zero-triggered in-place huge reallocation zeroing.  (@jasone)
+  - Fix heap profiling context leaks in reallocation edge cases.  (@jasone)
+
+* 4.2.0 (May 12, 2016)
+
+  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)
+
+  Optimizations:
+  - 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)
+
+* 4.1.1 (May 3, 2016)
+
+  This bugfix release resolves a variety of mostly minor issues, though the
+  bitmap fix is critical for 64-bit Windows.
+
+  Bug fixes:
+  - Fix the linear scan version of bitmap_sfu() to shift by the proper amount
+    even when sizeof(long) is not the same as sizeof(void *), as on 64-bit
+    Windows.  (@jasone)
+  - Fix hashing functions to avoid unaligned memory accesses (and resulting
+    crashes).  This is relevant at least to some ARM-based platforms.
+    (@rkmisra)
+  - Fix fork()-related lock rank ordering reversals.  These reversals were
+    unlikely to cause deadlocks in practice except when heap profiling was
+    enabled and active.  (@jasone)
+  - Fix various chunk leaks in OOM code paths.  (@jasone)
+  - Fix malloc_stats_print() to print opt.narenas correctly.  (@jasone)
+  - Fix MSVC-specific build/test issues.  (@rustyx, @yuslepukhin)
+  - Fix a variety of test failures that were due to test fragility rather than
+    core bugs.  (@jasone)
+
+* 4.1.0 (February 28, 2016)
+
+  This release is primarily about optimizations, but it also incorporates a lot
+  of portability-motivated refactoring and enhancements.  Many people worked on
+  this release, to an extent that even with the omission here of minor changes
+  (see git revision history), and of the people who reported and diagnosed
+  issues, so much of the work was contributed that starting with this release,
+  changes are annotated with author credits to help reflect the collaborative
+  effort involved.
+
+  New features:
+  - Implement decay-based unused dirty page purging, a major optimization with
+    mallctl API impact.  This is an alternative to the existing ratio-based
+    unused dirty page purging, and is intended to eventually become the sole
+    purging mechanism.  New mallctls:
+    + opt.purge
+    + opt.decay_time
+    + arena.<i>.decay
+    + arena.<i>.decay_time
+    + arenas.decay_time
+    + stats.arenas.<i>.decay_time
+    (@jasone, @cevans87)
+  - Add --with-malloc-conf, which makes it possible to embed a default
+    options string during configuration.  This was motivated by the desire to
+    specify --with-malloc-conf=purge:decay , since the default must remain
+    purge:ratio until the 5.0.0 release.  (@jasone)
+  - Add MS Visual Studio 2015 support.  (@rustyx, @yuslepukhin)
+  - Make *allocx() size class overflow behavior defined.  The maximum
+    size class is now less than PTRDIFF_MAX to protect applications against
+    numerical overflow, and all allocation functions are guaranteed to indicate
+    errors rather than potentially crashing if the request size exceeds the
+    maximum size class.  (@jasone)
+  - jeprof:
+    + Add raw heap profile support.  (@jasone)
+    + Add --retain and --exclude for backtrace symbol filtering.  (@jasone)
+
+  Optimizations:
+  - Optimize the fast path to combine various bootstrapping and configuration
+    checks and execute more streamlined code in the common case.  (@interwq)
+  - Use linear scan for small bitmaps (used for small object tracking).  In
+    addition to speeding up bitmap operations on 64-bit systems, this reduces
+    allocator metadata overhead by approximately 0.2%.  (@djwatson)
+  - Separate arena_avail trees, which substantially speeds up run tree
+    operations.  (@djwatson)
+  - Use memoization (boot-time-computed table) for run quantization.  Separate
+    arena_avail trees reduced the importance of this optimization.  (@jasone)
+  - Attempt mmap-based in-place huge reallocation.  This can dramatically speed
+    up incremental huge reallocation.  (@jasone)
+
+  Incompatible changes:
+  - Make opt.narenas unsigned rather than size_t.  (@jasone)
+
+  Bug fixes:
+  - Fix stats.cactive accounting regression.  (@rustyx, @jasone)
+  - Handle unaligned keys in hash().  This caused problems for some ARM systems.
+    (@jasone, @cferris1000)
+  - Refactor arenas array.  In addition to fixing a fork-related deadlock, this
+    makes arena lookups faster and simpler.  (@jasone)
+  - Move retained memory allocation out of the default chunk allocation
+    function, to a location that gets executed even if the application installs
+    a custom chunk allocation function.  This resolves a virtual memory leak.
+    (@buchgr)
+  - Fix a potential tsd cleanup leak.  (@cferris1000, @jasone)
+  - Fix run quantization.  In practice this bug had no impact unless
+    applications requested memory with alignment exceeding one page.
+    (@jasone, @djwatson)
+  - Fix LinuxThreads-specific bootstrapping deadlock.  (Cosmin Paraschiv)
+  - jeprof:
+    + Don't discard curl options if timeout is not defined.  (@djwatson)
+    + Detect failed profile fetches.  (@djwatson)
+  - Fix stats.arenas.<i>.{dss,lg_dirty_mult,decay_time,pactive,pdirty} for
+    --disable-stats case.  (@jasone)
+
+* 4.0.4 (October 24, 2015)
+
+  This bugfix release fixes another xallocx() regression.  No other regressions
+  have come to light in over a month, so this is likely a good starting point
+  for people who prefer to wait for "dot one" releases with all the major issues
+  shaken out.
+
+  Bug fixes:
+  - Fix xallocx(..., MALLOCX_ZERO to zero the last full trailing page of large
+    allocations that have been randomly assigned an offset of 0 when
+    --enable-cache-oblivious configure option is enabled.
+
 * 4.0.3 (September 24, 2015)
 
   This bugfix release continues the trend of xallocx() and heap profiling fixes.
@@ -38,7 +632,7 @@ brevity.  Much more detail can be found in the git revision history:
   these fixes, xallocx() now tries harder to partially fulfill requests for
   optional extra space.  Note that a couple of minor heap profiling
   optimizations are included, but these are better thought of as performance
-  fixes that were integral to disovering most of the other bugs.
+  fixes that were integral to discovering most of the other bugs.
 
   Optimizations:
   - Avoid a chunk metadata read in arena_prof_tctx_set(), since it is in the