Commit Graph

94 Commits

Author SHA1 Message Date
Jason Evans
19ff2cefba Implement the arena.<i>.reset mallctl.
This makes it possible to discard all of an arena's allocations in a
single operation.

This resolves #146.
2016-04-22 15:20:06 -07:00
hitstergtd
eb68842daf Doc typo fixes. 2016-04-18 15:47:45 -07:00
Jason Evans
b582d2ad94 Update implementation details docs re: PTRDIFF_MAX.
Document that the maximum size class is limited by PTRDIFF_MAX, rather
than the full address space.  This reflects changes that were part of
0c516a00c4 (Make *allocx() size class
overflow behavior defined.).
2016-03-31 12:31:10 -07:00
Jason Evans
0c516a00c4 Make *allocx() size class overflow behavior defined.
Limit supported size and alignment to HUGE_MAXCLASS, which in turn is
now limited to be less than PTRDIFF_MAX.

This resolves #278 and #295.
2016-02-25 15:29:49 -08:00
Jason Evans
5ec703dd33 Document the heap profile format.
This resolves #258.
2016-02-24 15:35:24 -08:00
Jason Evans
f591d2611a Update manual to reflect removal of global huge object tree.
This resolves #323.
2016-02-24 14:38:54 -08:00
Jason Evans
8f683b94a7 Make opt_narenas unsigned rather than size_t. 2016-02-24 13:03:48 -08:00
Jason Evans
243f7a0508 Implement decay-based unused dirty page purging.
This is an alternative to the existing ratio-based unused dirty page
purging, and is intended to eventually become the sole purging
mechanism.

Add mallctls:
- opt.purge
- opt.decay_time
- arena.<i>.decay
- arena.<i>.decay_time
- arenas.decay_time
- stats.arenas.<i>.decay_time

This resolves #325.
2016-02-19 20:56:21 -08:00
Jason Evans
f829009929 Add --with-malloc-conf.
Add --with-malloc-conf, which makes it possible to embed a default
options string during configuration.
2016-02-19 20:29:06 -08:00
Jason Evans
109712b681 Fix a documentation editing error. 2016-02-19 17:02:25 -08:00
Jason Evans
ea7449ffad Fix a manual editing error. 2015-10-19 16:56:05 -04:00
Jason Evans
92e96e3bfc Improve arena.<i>.chunk_hooks documentation formatting. 2015-08-14 13:46:08 -07:00
Jason Evans
38f864947b Update in-place reallocation documentation. 2015-08-14 00:55:44 -07:00
Jason Evans
a5dbaef08f Update large/huge size class cutoff documentation. 2015-08-14 00:35:11 -07:00
Jason Evans
8fadb1a8c2 Implement chunk hook support for page run commit/decommit.
Cascade from decommit to purge when purging unused dirty pages, so that
it is possible to decommit cleaned memory rather than just purging.  For
non-Windows debug builds, decommit runs rather than purging them, since
this causes access of deallocated runs to segfault.

This resolves #251.
2015-08-07 00:50:58 -07:00
Jason Evans
b49a334a64 Generalize chunk management hooks.
Add the "arena.<i>.chunk_hooks" mallctl, which replaces and expands on
the "arena.<i>.chunk.{alloc,dalloc,purge}" mallctls.  The chunk hooks
allow control over chunk allocation/deallocation, decommit/commit,
purging, and splitting/merging, such that the application can rely on
jemalloc's internal chunk caching and retaining functionality, yet
implement a variety of chunk management mechanisms and policies.

Merge the chunks_[sz]ad_{mmap,dss} red-black trees into
chunks_[sz]ad_retained.  This slightly reduces how hard jemalloc tries
to honor the dss precedence setting; prior to this change the precedence
setting was also consulted when recycling chunks.

Fix chunk purging.  Don't purge chunks in arena_purge_stashed(); instead
deallocate them in arena_unstash_purged(), so that the dirty memory
linkage remains valid until after the last time it is used.

This resolves #176 and #201.
2015-08-03 21:49:02 -07:00
Jason Evans
f2bc85298c Add the config.cache_oblivious mallctl. 2015-07-17 16:38:25 -07:00
Jason Evans
5bd879646c Change default chunk size from 256 KiB to 2 MiB.
This change improves interaction with transparent huge pages, e.g.
reduced page faults (at least in the absence of unused dirty page
purging).
2015-07-15 17:15:26 -07:00
Jason Evans
56048baeb4 Clarify relationship between stats.resident and stats.mapped. 2015-05-29 19:21:10 -07:00
Jason Evans
7041720ac2 Rename pprof to jeprof.
This rename avoids installation collisions with the upstream gperftools.
Additionally, jemalloc's per thread heap profile functionality
introduced an incompatible file format, so it's now worthwhile to
clearly distinguish jemalloc's version of this script from the upstream
version.

This resolves #229.
2015-05-01 12:31:12 -07:00
Qinfan Wu
897503521d Fix mallctl doc: arenas.hchunk.<i>.size 2015-04-30 09:48:49 -07:00
Jason Evans
562d266511 Add the "stats.arenas.<i>.lg_dirty_mult" mallctl. 2015-03-24 16:41:38 -07:00
Jason Evans
4acd75a694 Add the "stats.allocated" mallctl. 2015-03-23 17:26:53 -07:00
Jason Evans
8d6a3e8321 Implement dynamic per arena control over dirty page purging.
Add mallctls:
- arenas.lg_dirty_mult is initialized via opt.lg_dirty_mult, and can be
  modified to change the initial lg_dirty_mult setting for newly created
  arenas.
- arena.<i>.lg_dirty_mult controls an individual arena's dirty page
  purging threshold, and synchronously triggers any purging that may be
  necessary to maintain the constraint.
- arena.<i>.chunk.purge allows the per arena dirty page purging function
  to be replaced.

This resolves #93.
2015-03-18 18:55:33 -07:00
Jason Evans
f044bb219e Change default chunk size from 4 MiB to 256 KiB.
Recent changes have improved huge allocation scalability, which removes
upward pressure to set the chunk size so large that huge allocations are
rare.  Smaller chunks are more likely to completely drain, so set the
default to the smallest size that doesn't leave excessive unusable
trailing space in chunk headers.
2015-03-06 20:18:34 -08:00
Jason Evans
cbf3a6d703 Move centralized chunk management into arenas.
Migrate all centralized data structures related to huge allocations and
recyclable chunks into arena_t, so that each arena can manage huge
allocations and recyclable virtual memory completely independently of
other arenas.

Add chunk node caching to arenas, in order to avoid contention on the
base allocator.

Use chunks_rtree to look up huge allocations rather than a red-black
tree.  Maintain a per arena unsorted list of huge allocations (which
will be needed to enumerate huge allocations during arena reset).

Remove the --enable-ivsalloc option, make ivsalloc() always available,
and use it for size queries if --enable-debug is enabled.  The only
practical implications to this removal are that 1) ivsalloc() is now
always available during live debugging (and the underlying radix tree is
available during core-based debugging), and 2) size query validation can
no longer be enabled independent of --enable-debug.

Remove the stats.chunks.{current,total,high} mallctls, and replace their
underlying statistics with simpler atomically updated counters used
exclusively for gdump triggering.  These statistics are no longer very
useful because each arena manages chunks independently, and per arena
statistics provide similar information.

Simplify chunk synchronization code, now that base chunk allocation
cannot cause recursive lock acquisition.
2015-02-12 00:15:56 -08:00
Jason Evans
1cb181ed63 Implement explicit tcache support.
Add the MALLOCX_TCACHE() and MALLOCX_TCACHE_NONE macros, which can be
used in conjunction with the *allocx() API.

Add the tcache.create, tcache.flush, and tcache.destroy mallctls.

This resolves #145.
2015-02-09 17:44:48 -08:00
Jason Evans
5b8ed5b7c9 Implement the prof.gdump mallctl.
This feature makes it possible to toggle the gdump feature on/off during
program execution, whereas the the opt.prof_dump mallctl value can only
be set during program startup.

This resolves #72.
2015-01-25 21:21:35 -08:00
Jason Evans
4581b97809 Implement metadata statistics.
There are three categories of metadata:

- Base allocations are used for bootstrap-sensitive internal allocator
  data structures.
- Arena chunk headers comprise pages which track the states of the
  non-metadata pages.
- Internal allocations differ from application-originated allocations
  in that they are for internal use, and that they are omitted from heap
  profiles.

The metadata statistics comprise the metadata categories as follows:

- stats.metadata: All metadata -- base + arena chunk headers + internal
  allocations.
- stats.arenas.<i>.metadata.mapped: Arena chunk headers.
- stats.arenas.<i>.metadata.allocated: Internal allocations.  This is
  reported separately from the other metadata statistics because it
  overlaps with the allocated and active statistics, whereas the other
  metadata statistics do not.

Base allocations are not reported separately, though their magnitude can
be computed by subtracting the arena-specific metadata.

This resolves #163.
2015-01-23 23:34:43 -08:00
Jason Evans
228b2e9242 Document under what circumstances in-place resizing succeeds.
This resolves #100.
2015-01-22 15:28:25 -08:00
Guilherme Goncalves
2c5cb613df Introduce two new modes of junk filling: "alloc" and "free".
In addition to true/false, opt.junk can now be either "alloc" or "free",
giving applications the possibility of junking memory only on allocation
or deallocation.

This resolves #172.
2014-12-14 17:07:26 -08:00
Jason Evans
9b41ac909f Fix huge allocation statistics. 2014-10-14 22:20:00 -07:00
Jason Evans
0cdabd2d48 Update size class documentation. 2014-10-14 22:19:21 -07:00
Jason Evans
3c4d92e82a Add per size class huge allocation statistics.
Add per size class huge allocation statistics, and normalize various
stats:
- Change the arenas.nlruns type from size_t to unsigned.
- Add the arenas.nhchunks and arenas.hchunks.<i>.size mallctl's.
- Replace the stats.arenas.<i>.bins.<j>.allocated mallctl with
  stats.arenas.<i>.bins.<j>.curregs .
- Add the stats.arenas.<i>.hchunks.<j>.nmalloc,
  stats.arenas.<i>.hchunks.<j>.ndalloc,
  stats.arenas.<i>.hchunks.<j>.nrequests, and
  stats.arenas.<i>.hchunks.<j>.curhchunks mallctl's.
2014-10-12 23:02:10 -07:00
Jason Evans
57efa7bb0e Avoid atexit(3) when possible, disable prof_final by default.
atexit(3) can deadlock internally during its own initialization if
jemalloc calls atexit() during jemalloc initialization.  Mitigate the
impact by restructuring prof initialization to avoid calling atexit()
unless the registered function will actually dump a final heap profile.

Additionally, disable prof_final by default so that this land mine is
opt-in rather than opt-out.

This resolves #144.
2014-10-08 18:08:00 -07:00
Jason Evans
3c3b3b1a94 Fix a docbook element nesting nit.
According to the docbook documentation for <funcprototype>, its parent
must be <funcsynopsis>; fix accordingly.  Nonetheless, the man page
processor fails badly when this construct is embedded in a <para> (which
is documented to be legal), although the html processor does fine.
2014-10-05 14:48:44 -07:00
Daniel Micay
a95018ee81 Attempt to expand huge allocations in-place.
This adds support for expanding huge allocations in-place by requesting
memory at a specific address from the chunk allocator.

It's currently only implemented for the chunk recycling path, although
in theory it could also be done by optimistically allocating new chunks.
On Linux, it could attempt an in-place mremap. However, that won't work
in practice since the heap is grown downwards and memory is not unmapped
(in a normal build, at least).

Repeated vector reallocation micro-benchmark:

    #include <string.h>
    #include <stdlib.h>

    int main(void) {
        for (size_t i = 0; i < 100; i++) {
            void *ptr = NULL;
            size_t old_size = 0;
            for (size_t size = 4; size < (1 << 30); size *= 2) {
                ptr = realloc(ptr, size);
                if (!ptr) return 1;
                memset(ptr + old_size, 0xff, size - old_size);
                old_size = size;
            }
            free(ptr);
        }
    }

The glibc allocator fails to do any in-place reallocations on this
benchmark once it passes the M_MMAP_THRESHOLD (default 128k) but it
elides the cost of copies via mremap, which is currently not something
that jemalloc can use.

With this improvement, jemalloc still fails to do any in-place huge
reallocations for the first outer loop, but then succeeds 100% of the
time for the remaining 99 iterations. The time spent doing allocations
and copies drops down to under 5%, with nearly all of it spent doing
purging + faulting (when huge pages are disabled) and the array memset.

An improved mremap API (MREMAP_RETAIN - #138) would be far more general
but this is a portable optimization and would still be useful on Linux
for xallocx.

Numbers with transparent huge pages enabled:

glibc (copies elided via MREMAP_MAYMOVE): 8.471s

jemalloc: 17.816s
jemalloc + no-op madvise: 13.236s

jemalloc + this commit: 6.787s
jemalloc + this commit + no-op madvise: 6.144s

Numbers with transparent huge pages disabled:

glibc (copies elided via MREMAP_MAYMOVE): 15.403s

jemalloc: 39.456s
jemalloc + no-op madvise: 12.768s

jemalloc + this commit: 15.534s
jemalloc + this commit + no-op madvise: 6.354s

Closes #137
2014-10-05 14:47:01 -07:00
Jason Evans
e9a3fa2e09 Add missing header includes in jemalloc/jemalloc.h .
Add stdlib.h, stdbool.h, and stdint.h to jemalloc/jemalloc.h so that
applications only have to #include <jemalloc/jemalloc.h>.

This resolves #132.
2014-10-05 12:05:37 -07:00
Jason Evans
fc12c0b8bc Implement/test/fix prof-related mallctl's.
Implement/test/fix the opt.prof_thread_active_init,
prof.thread_active_init, and thread.prof.active mallctl's.

Test/fix the thread.prof.name mallctl.

Refactor opt_prof_active to be read-only and move mutable state into the
prof_active variable.  Stop leaning on ctl-related locking for
protection.
2014-10-03 23:25:30 -07:00
Jason Evans
20c31deaae Test prof.reset mallctl and fix numerous discovered bugs. 2014-10-02 23:01:10 -07:00
Daniel Micay
4cfe55166e Add support for sized deallocation.
This adds a new `sdallocx` function to the external API, allowing the
size to be passed by the caller.  It avoids some extra reads in the
thread cache fast path.  In the case where stats are enabled, this
avoids the work of calculating the size from the pointer.

An assertion validates the size that's passed in, so enabling debugging
will allow users of the API to debug cases where an incorrect size is
passed in.

The performance win for a contrived microbenchmark doing an allocation
and immediately freeing it is ~10%.  It may have a different impact on a
real workload.

Closes #28
2014-09-08 17:34:24 -07:00
Jason Evans
602c8e0971 Implement per thread heap profiling.
Rename data structures (prof_thr_cnt_t-->prof_tctx_t,
prof_ctx_t-->prof_gctx_t), and convert to storing a prof_tctx_t for
sampled objects.

Convert PROF_ALLOC_PREP() to prof_alloc_prep(), since precise backtrace
depth within jemalloc functions is no longer an issue (pprof prunes
irrelevant frames).

Implement mallctl's:
- prof.reset implements full sample data reset, and optional change of
  sample interval.
- prof.lg_sample reads the current sample interval (opt.lg_prof_sample
  was the permanent source of truth prior to prof.reset).
- thread.prof.name provides naming capability for threads within heap
  profile dumps.
- thread.prof.active makes it possible to activate/deactivate heap
  profiling for individual threads.

Modify the heap dump files to contain per thread heap profile data.
This change is incompatible with the existing pprof, which will require
enhancements to read and process the enriched data.
2014-08-19 21:31:16 -07:00
Jason Evans
b4d62cd61b Minor doc edit. 2014-05-15 22:46:24 -07:00
Jason Evans
e2deab7a75 Refactor huge allocation to be managed by arenas.
Refactor huge allocation to be managed by arenas (though the global
red-black tree of huge allocations remains for lookup during
deallocation).  This is the logical conclusion of recent changes that 1)
made per arena dss precedence apply to huge allocation, and 2) made it
possible to replace the per arena chunk allocation/deallocation
functions.

Remove the top level huge stats, and replace them with per arena huge
stats.

Normalize function names and types to *dalloc* (some were *dealloc*).

Remove the --enable-mremap option.  As jemalloc currently operates, this
is a performace regression for some applications, but planned work to
logarithmically space huge size classes should provide similar amortized
performance.  The motivation for this change was that mremap-based huge
reallocation forced leaky abstractions that prevented refactoring.
2014-05-15 22:36:41 -07:00
aravind
fb7fe50a88 Add support for user-specified chunk allocators/deallocators.
Add new mallctl endpoints "arena<i>.chunk.alloc" and
"arena<i>.chunk.dealloc" to allow userspace to configure
jemalloc's chunk allocator and deallocator on a per-arena
basis.
2014-05-12 10:46:03 -07:00
Jason Evans
bd87b01999 Optimize Valgrind integration.
Forcefully disable tcache if running inside Valgrind, and remove
Valgrind calls in tcache-specific code.

Restructure Valgrind-related code to move most Valgrind calls out of the
fast path functions.

Take advantage of static knowledge to elide some branches in
JEMALLOC_VALGRIND_REALLOC().
2014-04-15 16:49:57 -07:00
Jason Evans
ecd3e59ca3 Remove the "opt.valgrind" mallctl.
Remove the "opt.valgrind" mallctl because it is unnecessary -- jemalloc
automatically detects whether it is running inside valgrind.
2014-04-15 14:33:50 -07:00
Jason Evans
a2c719b374 Remove the "arenas.purge" mallctl.
Remove the "arenas.purge" mallctl, which was obsoleted by the
"arena.<i>.purge" mallctl in 3.1.0.
2014-04-15 12:46:28 -07:00
Jason Evans
4d434adb14 Make dss non-optional, and fix an "arena.<i>.dss" mallctl bug.
Make dss non-optional on all platforms which support sbrk(2).

Fix the "arena.<i>.dss" mallctl to return an error if "primary" or
"secondary" precedence is specified, but sbrk(2) is not supported.
2014-04-15 12:09:48 -07:00
Jason Evans
24a4ba77e1 Update MALLOCX_ARENA() documentation.
Update MALLOCX_ARENA() documentation to no longer claim that it has no
effect for huge region allocations.
2014-04-14 22:38:59 -07:00