2.0.0

This version focuses on the experimental *allocm() API, and on improved run-time configuration/introspection. Nonetheless, numerous performance improvements are also included.

New features:

• Implement the experimental {,r,s,d}allocm() API, which provides a superset
  of the functionality available via malloc(), calloc(), posix_memalign(),
  realloc(), malloc_usable_size(), and free(). These functions can be used to
  allocate/reallocate aligned zeroed memory, ask for optional extra memory
  during reallocation, prevent object movement during reallocation, etc.
• Replace JEMALLOC_OPTIONS/JEMALLOC_PROF_PREFIX with MALLOC_CONF, which is
  more human-readable, and more flexible. For example:
  JEMALLOC_OPTIONS=AJP
  is now:
  MALLOC_CONF=abort:true,fill:true,stats_print:true
• Port to Apple OS X. Sponsored by Mozilla.
• Make it possible for the application to control thread-->arena mappings via
  the "thread.arena" mallctl.
• Add compile-time support for all TLS-related functionality via pthreads TSD.
  This is mainly of interest for OS X, which does not support TLS, but has a
  TSD implementation with similar performance.
• Override memalign() and valloc() if they are provided by the system.
• Add the "arenas.purge" mallctl, which can be used to synchronously purge all
  dirty unused pages.
• Make cumulative heap profiling data optional, so that it is possible to
  limit the amount of memory consumed by heap profiling data structures.
• Add per thread allocation counters that can be accessed via the
  "thread.allocated" and "thread.deallocated" mallctls.

Incompatible changes:

• Remove JEMALLOC_OPTIONS and malloc_options (see MALLOC_CONF above).
• Increase default backtrace depth from 4 to 128 for heap profiling.
• Disable interval-based profile dumps by default.

Bug fixes:

• Remove bad assertions in fork handler functions. These assertions could
  cause aborts for some combinations of configure settings.
• Fix strerror_r() usage to deal with non-standard semantics in GNU libc.
• Fix leak context reporting. This bug tended to cause the number of contexts
  to be underreported (though the reported number of objects and bytes were
  correct).
• Fix a realloc() bug for large in-place growing reallocation. This bug could
  cause memory corruption, but it was hard to trigger.
• Fix an allocation bug for small allocations that could be triggered if
  multiple threads raced to create a new run of backing pages.
• Enhance the heap profiler to trigger samples based on usable size, rather
  than request size.
• Fix a heap profiling bug due to sometimes losing track of requested object
  size for sampled objects.

1.0.3

Bug fixes:

• Fix the libunwind-based implementation of stack backtracing (used for heap
  profiling). This bug could cause zero-length backtraces to be reported.
• Add a missing mutex unlock in library initialization code. If multiple
  threads raced to initialize malloc, some of them could end up permanently
  blocked.

1.0.2

Bug fixes:

• Fix junk filling of large objects, which could cause memory corruption.
• Add MAP_NORESERVE support for chunk mapping, because otherwise virtual
  memory limits could cause swap file configuration to fail. Contributed by
  Jordan DeLong.

1.0.1

Bug fixes:

• Fix compilation when --enable-fill is specified.
• Fix threads-related profiling bugs that affected accuracy and caused memory
  to be leaked during thread exit.
• Fix dirty page purging race conditions that could cause crashes.
• Fix crash in tcache flushing code during thread destruction.

1.0.0

This release focuses on speed and run-time introspection. Numerous algorithmic improvements make this release substantially faster than its predecessors.

New features:

• Implement autoconf-based configuration system.
• Add mallctl*(), for the purposes of introspection and run-time
  configuration.
• Make it possible for the application to manually flush a thread's cache, via
  the "tcache.flush" mallctl.
• Base maximum dirty page count on proportion of active memory.
• Compute various addtional run-time statistics, including per size class
  statistics for large objects.
• Expose malloc_stats_print(), which can be called repeatedly by the
  application.
• Simplify the malloc_message() signature to only take one string argument,
  and incorporate an opaque data pointer argument for use by the application
  in combination with malloc_stats_print().
• Add support for allocation backed by one or more swap files, and allow the
  application to disable over-commit if swap files are in use.
• Implement allocation profiling and leak checking.

Removed features:

• Remove the dynamic arena rebalancing code, since thread-specific caching
  reduces its utility.

Bug fixes:

• Modify chunk allocation to work when address space layout randomization
  (ASLR) is in use.
• Fix thread cleanup bugs related to TLS destruction.
• Handle 0-size allocation requests in posix_memalign().
• Fix a chunk leak. The leaked chunks were never touched, so this impacted
  virtual memory usage, but not physical memory usage.