Replace the single-character run-time flags with key/value pairs, which
can be set via the malloc_conf global, /etc/malloc.conf, and the
MALLOC_CONF environment variable.
Replace the JEMALLOC_PROF_PREFIX environment variable with the
"opt.prof_prefix" option.
Replace umax2s() with u2s().
Add the "thread.allocated" and "thread.deallocated" mallctls, which can
be used to query the total number of bytes ever allocated/deallocated by
the calling thread.
Add s2u() and sa2u(), which can be used to compute the usable size that
will result from an allocation request of a particular size/alignment.
Re-factor ipalloc() to use sa2u().
Enhance the heap profiler to trigger samples based on usable size,
rather than request size. This has a subtle, but important, impact on
the accuracy of heap sampling. For example, previous to this change,
16- and 17-byte objects were sampled at nearly the same rate, but
17-byte objects actually consume 32 bytes each. Therefore it was
possible for the sample to be somewhat skewed compared to actual memory
usage of the allocated objects.
Add the R option to control whether cumulative heap profile data
are maintained. Add the T option to control the size of per thread
backtrace caches, primarily because when the R option is specified,
backtraces that no longer have allocations associated with them are
discarded as soon as no thread caches refer to them.
It is common to have to specify something like JEMALLOC_OPTIONS=F31i,
because interval-based dumps are often unuseful or too expensive.
Therefore, disable interval-based dumps by default. To get the previous
default behavior it is now necessary to specify 31I as part of the
options.
Add allocm(), rallocm(), sallocm(), and dallocm(), which are a
functional superset of malloc(), calloc(), posix_memalign(),
malloc_usable_size(), and free().
Move the table of size classes from jemalloc.c to the manual page. When
manually formatting the manual page, it is now necessary to use:
nroff -man -t jemalloc.3
Fix divide-by-zero error in pprof. It is possible for sample contexts
to currently have no associated objects, but the cumulative statistics
are still useful, depending on how the user invokes pprof. Since
jemalloc intentionally does not filter such contexts, take care not to
divide by 0 when re-scaling for v2 heap sampling.
Install pprof as part of 'make install'.
Update pprof documentation.
Add the E/e options to control whether the application starts with
sampling active/inactive (secondary control to F/f). Add the
prof.active mallctl so that the application can activate/deactivate
sampling on the fly.
Make it possible to disable interval-triggered profile dumping, even if
profiling is enabled. This is useful if the user only wants a single
dump at exit, or if the application manually triggers profile dumps.
Remove medium size classes, because concurrent dirty page purging is
no longer capable of purging inactive dirty pages inside active runs
(due to recent arena/bin locking changes).
Enhance tcache to support caching large objects, so that the same range
of size classes is still cached, despite the removal of medium size
class support.
For bin-related allocation, protect data structures with bin locks
rather than arena locks. Arena locks remain for run
allocation/deallocation and other miscellaneous operations.
Restructure statistics counters to maintain per bin
allocated/nmalloc/ndalloc, but continue to provide arena-wide statistics
via aggregation in the ctl code.
Use chains of cached objects, rather than using arrays of pointers.
Since tcache_bin_t is no longer dynamically sized, convert tcache_t's
tbin to an array of structures, rather than an array of pointers. This
implicitly removes tcache_bin_{create,destroy}(), which further
simplifies the fast path for malloc/free.
Use cacheline alignment for tcache_t allocations.
Remove runtime configuration option for number of tcache bin slots, and
replace it with a boolean option for enabling/disabling tcache.
Limit the number of tcache objects to the lesser of TCACHE_NSLOTS_MAX
and 2X the number of regions per run for the size class.
For GC-triggered flush, discard 3/4 of the objects below the low water
mark, rather than 1/2.
Convert chunks_dirty from a red-black tree to a doubly linked list,
and use it to purge dirty pages from chunks in FIFO order.
Add a lock around the code that purges dirty pages via madvise(2), in
order to avoid kernel contention. If lock acquisition fails,
indefinitely postpone purging dirty pages.
Add a lower limit of one chunk worth of dirty pages per arena for
purging, in addition to the active:dirty ratio.
When purging, purge all dirty pages from at least one chunk, but rather
than purging enough pages to drop to half the purging threshold, merely
drop to the threshold.
Remove all functionality related to tracing. This functionality was
useful for understanding memory fragmentation during early algorithmic
design of jemalloc, but it had little utility for non-trivial
applications, due to the sheer volume of data written to disk.
Fix a type mismatch for "arenas.nlruns" mallctl access. This bug caused
a crash during statistics printing on 64-bit systems.
Fix the "stats.active" mallctl to include active memory in huge objects.
Report active bytes for the whole application, as well as per arena.
Remove several unused variables.
Replace chunk stats code that was missing locking; this fixes a race
condition that could corrupt chunk statistics.
Converting malloc_stats_print() to use mallctl*().
Add a missing semicolon in th DSS code.
Convert malloc_tcache_flush() to a mallctl.
Convert malloc_swap_enable() to a set of mallctl's.
Add the 'G'/'g' and 'H'/'h' MALLOC_OPTIONS flags.
Add the malloc_tcache_flush() function.
Disable thread-specific caching until the application goes multi-threaded.
Add the 'M' and 'm' MALLOC_OPTIONS flags, which control the maximum medium size
class.
Relax the cap on small/medium run size to arena_maxclass.
Reduce arena_run_reg_dalloc() integer division code complexity.
Increase the default chunk size from 1MiB to 4MiB.
