This (experimental, undocumented) functionality can be used by users to track
various statistics of interest at a finer level of granularity than the thread.
For now, this is just a stub containing the ecaches, with no surrounding code
changed. Eventually all the core allocator bits will be moved in, in the
subsequent stack of commits.
This distinguishes it from the PA mapped stat, which is now named "pa_mapped" to
avoid confusion. The (derived) arena stat includes base memory, and the PA stat
is no longer partially derived.
This pulls out the various abstractions where some stats counter is sometimes an
atomic, sometimes a plain variable, sometimes always protected by a lock,
sometimes protected by reads but not writes, etc. With this change, these cases
are treated consistently, and access patterns tagged.
In the process, we fix a few missed-update bugs (where one caller assumes
"protected-by-a-lock" semantics and another does not).
Add options stats_interval and stats_interval_opts to allow interval based stats
printing. This provides an easy way to collect stats without code changes,
because opt.stats_print may not work (some binaries never exit).
This will eventually completely wrap the eset, and handle concurrency,
allocation, and deallocation. For now, we only pull out the mutex from the
eset.
Specifically, the extent_arena_[g|s]et functions and the address randomization.
These are the only things that tie the extent struct itself to the arena code.
Added a new stats row to aggregate the maximum value of mutex counters for each
background threads. Given that the per bg thd mutex is not expected to be
contended, this counter is mainly for sanity check / debugging.
The new experimental mallctl exposes the arena pactive counter to applications,
which allows fast read w/o going through the mallctl / epoch steps. This is
particularly useful when frequent balancing is required, e.g. when having
multiple manual arenas, and threads are multiplexed to them based on usage.
If the confirm_conf option is set, when the program starts, each of
the four malloc_conf strings will be printed, and each option will
be printed when being set.
Small is added purely for convenience. Large flushes wasn't tracked before and
can be useful in analysis. Large fill simply reports nmalloc, since there is no
batch fill for large currently.
When config_stats is enabled track the size of bin->slabs_nonfull in
the new nonfull_slabs counter in bin_stats_t. This metric should be
useful for establishing an upper ceiling on the savings possible by
meshing.
The analytics tool is put under experimental.utilization namespace in
mallctl. Input is one pointer or an array of pointers and the output
is a list of memory utilization statistics.
For low arena count settings, the huge threshold feature may trigger an unwanted
bg thd creation. Given that the huge arena does eager purging by default,
bypass bg thd creation when initializing the huge arena.
This makes it possible to have multiple set of bins in an arena, which improves
arena scalability because the bins (especially the small ones) are always the
limiting factor in production workload.
A bin shard is picked on allocation; each extent tracks the bin shard id for
deallocation. The shard size will be determined using runtime options.
This class removes almost all the dependencies on size_classes.h, accessing the
data there only via the new module sc.h, which does not depend on any
configuration options.
In a subsequent commit, we'll remove the configure-time size class computations,
doing them at boot time, instead.
Before this commit jemalloc produced many warnings when compiled with -Wextra
with both Clang and GCC. This commit fixes the issues raised by these warnings
or suppresses them if they were spurious at least for the Clang and GCC
versions covered by CI.
This commit:
* adds `JEMALLOC_DIAGNOSTIC` macros: `JEMALLOC_DIAGNOSTIC_{PUSH,POP}` are
used to modify the stack of enabled diagnostics. The
`JEMALLOC_DIAGNOSTIC_IGNORE_...` macros are used to ignore a concrete
diagnostic.
* adds `JEMALLOC_FALLTHROUGH` macro to explicitly state that falling
through `case` labels in a `switch` statement is intended
* Removes all UNUSED annotations on function parameters. The warning
-Wunused-parameter is now disabled globally in
`jemalloc_internal_macros.h` for all translation units that include
that header. It is never re-enabled since that header cannot be
included by users.
* locally suppresses some -Wextra diagnostics:
* `-Wmissing-field-initializer` is buggy in older Clang and GCC versions,
where it does not understanding that, in C, `= {0}` is a common C idiom
to initialize a struct to zero
* `-Wtype-bounds` is suppressed in a particular situation where a generic
macro, used in multiple different places, compares an unsigned integer for
smaller than zero, which is always true.
* `-Walloc-larger-than-size=` diagnostics warn when an allocation function is
called with a size that is too large (out-of-range). These are suppressed in
the parts of the tests where `jemalloc` explicitly does this to test that the
allocation functions fail properly.
* adds a new CI build bot that runs the log unit test on CI.
Closes#1196 .
Looking at the thread counts in our services, jemalloc's background thread
is useful, but mostly idle. Add a config option to tune down the number of threads.
"always" marks all user mappings as MADV_HUGEPAGE; while "never" marks all
mappings as MADV_NOHUGEPAGE. The default setting "default" does not change any
settings. Note that all the madvise calls are part of the default extent hooks
by design, so that customized extent hooks have complete control over the
mappings including hugepage settings.
