Commit Graph

138 Commits

Author SHA1 Message Date
Jason Evans
3e3caf03af Merge pull request #73 from bmaurer/smallmalloc
Smaller malloc hot path
2014-04-16 16:33:21 -07:00
Ben Maurer
021136ce4d Create a const array with only a small bin to size map 2014-04-16 14:31:24 -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
9b0cbf0850 Remove support for non-prof-promote heap profiling metadata.
Make promotion of sampled small objects to large objects mandatory, so
that profiling metadata can always be stored in the chunk map, rather
than requiring one pointer per small region in each small-region page
run.  In practice the non-prof-promote code was only useful when using
jemalloc to track all objects and report them as leaks at program exit.
However, Valgrind is at least as good a tool for this particular use
case.

Furthermore, the non-prof-promote code is getting in the way of
some optimizations that will make heap profiling much cheaper for the
predominant use case (sampling a small representative proportion of all
allocations).
2014-04-11 14:24:51 -07:00
Ben Maurer
be8e59f5a6 Don't dereference chunk->arena in free() hot path
When you call free() we load chunk->arena even though that
data isn't used on the tcache hot path.

In profiling some FB applications, I found that ~30% of the
dTLB misses in the free() function come from this line. With
4 MB chunks, the arena_chunk_t->map is ~ 32 KB (1024 pages
in the chunk, 4 8 byte pointers in arena_chunk_map_t). This
means there's only a 1/8 chance of the page containing
chunk->arena also comtaining the map bits.
2014-04-05 15:59:08 -07:00
Jason Evans
aa5113b1fd Refactor overly large/complex functions.
Refactor overly large functions by breaking out helper functions.

Refactor overly complex multi-purpose functions into separate more
specific functions.
2014-01-14 16:23:03 -08:00
Jason Evans
b2c31660be Extract profiling code from [re]allocation functions.
Extract profiling code from malloc(), imemalign(), calloc(), realloc(),
mallocx(), rallocx(), and xallocx().  This slightly reduces the amount
of code compiled into the fast paths, but the primary benefit is the
combinatorial complexity reduction.

Simplify iralloc[t]() by creating a separate ixalloc() that handles the
no-move cases.

Further simplify [mrxn]allocx() (and by implication [mrn]allocm()) to
make request size overflows due to size class and/or alignment
constraints trigger undefined behavior (detected by debug-only
assertions).

Report ENOMEM rather than EINVAL if an OOM occurs during heap profiling
backtrace creation in imemalign().  This bug impacted posix_memalign()
and aligned_alloc().
2014-01-12 15:41:05 -08:00
Jason Evans
6b694c4d47 Add junk/zero filling unit tests, and fix discovered bugs.
Fix growing large reallocation to junk fill new space.

Fix huge deallocation to junk fill when munmap is disabled.
2014-01-07 16:54:17 -08:00
Jason Evans
0d6c5d8bd0 Add quarantine unit tests.
Verify that freed regions are quarantined, and that redzone corruption
is detected.

Introduce a testing idiom for intercepting/replacing internal functions.
In this case the replaced function is ordinarily a static function, but
the idiom should work similarly for library-private functions.
2013-12-17 15:19:12 -08:00
Jason Evans
5fbad0902b Finish arena_prof_ctx_set() optimization.
Delay reading the mapbits until it's unavoidable.
2013-12-15 22:08:44 -08:00
Jason Evans
665769357c Optimize arena_prof_ctx_set().
Refactor such that arena_prof_ctx_set() receives usize as an argument,
and use it to determine whether to handle ptr as a small region, rather
than reading the chunk page map.
2013-12-15 21:57:02 -08:00
Jason Evans
c368f8c8a2 Remove unnecessary zeroing in arena_palloc(). 2013-10-29 18:31:17 -07:00
Jason Evans
87a02d2bb1 Fix a Valgrind integration flaw.
Fix a Valgrind integration flaw that caused Valgrind warnings about
reads of uninitialized memory in arena chunk headers.
2013-10-19 21:40:20 -07:00
Jason Evans
88c222c8e9 Fix a prof-related locking order bug.
Fix a locking order bug that could cause deadlock during fork if heap
profiling were enabled.
2013-02-06 11:59:30 -08:00
Jason Evans
88393cb0eb Add and use JEMALLOC_ALWAYS_INLINE.
Add JEMALLOC_ALWAYS_INLINE and use it to guarantee that the entire fast
paths of the primary allocation/deallocation functions are inlined.
2013-01-22 08:45:43 -08:00
Jason Evans
a3b3386ddd Avoid arena_prof_accum()-related locking when possible.
Refactor arena_prof_accum() and its callers to avoid arena locking when
prof_interval is 0 (as when profiling is disabled).

Reported by Ben Maurer.
2012-11-13 13:47:53 -08:00
Jason Evans
e3d13060c8 Purge unused dirty pages in a fragmentation-reducing order.
Purge unused dirty pages in an order that first performs clean/dirty run
defragmentation, in order to mitigate available run fragmentation.

Remove the limitation that prevented purging unless at least one chunk
worth of dirty pages had accumulated in an arena.  This limitation was
intended to avoid excessive purging for small applications, but the
threshold was arbitrary, and the effect of questionable utility.

Relax opt_lg_dirty_mult from 5 to 3.  This compensates for increased
likelihood of allocating clean runs, given the same ratio of clean:dirty
runs, and reduces the potential for repeated purging in pathological
large malloc/free loops that push the active:dirty page ratio just over
the purge threshold.
2012-11-06 00:59:53 -08:00
Jason Evans
609ae595f0 Add arena-specific and selective dss allocation.
Add the "arenas.extend" mallctl, so that it is possible to create new
arenas that are outside the set that jemalloc automatically multiplexes
threads onto.

Add the ALLOCM_ARENA() flag for {,r,d}allocm(), so that it is possible
to explicitly allocate from a particular arena.

Add the "opt.dss" mallctl, which controls the default precedence of dss
allocation relative to mmap allocation.

Add the "arena.<i>.dss" mallctl, which makes it possible to set the
default dss precedence on a per arena or global basis.

Add the "arena.<i>.purge" mallctl, which obsoletes "arenas.purge".

Add the "stats.arenas.<i>.dss" mallctl.
2012-10-12 18:26:16 -07:00
Jason Evans
d8ceef6c55 Fix large calloc() zeroing bugs.
Refactor code such that arena_mapbits_{large,small}_set() always
preserves the unzeroed flag, and manually manipulate the unzeroed flag
in the one case where it actually gets reset (in arena_chunk_purge()).
This fixes unzeroed preservation bugs in arena_run_split() and
arena_ralloc_large_grow().  These bugs caused large calloc() to return
non-zeroed memory under some circumstances.
2012-05-10 21:49:43 -07:00
Jason Evans
53bd42c1fe Update a comment. 2012-05-10 00:18:46 -07:00
Jason Evans
80737c3323 Further optimize and harden arena_salloc().
Further optimize arena_salloc() to only look at the binind chunk map
bits in the common case.

Add more sanity checks to arena_salloc() that detect chunk map
inconsistencies for large allocations (whether due to allocator bugs or
application bugs).
2012-05-02 16:11:03 -07:00
Jason Evans
203484e2ea Optimize malloc() and free() fast paths.
Embed the bin index for small page runs into the chunk page map, in
order to omit [...] in the following dependent load sequence:
  ptr-->mapelm-->[run-->bin-->]bin_info

Move various non-critcal code out of the inlined function chain into
helper functions (tcache_event_hard(), arena_dalloc_small(), and
locking).
2012-05-02 00:30:36 -07:00
Jason Evans
f7088e6c99 Make arena_salloc() an inline function. 2012-04-19 18:28:03 -07:00
Jason Evans
5ff709c264 Normalize aligned allocation algorithms.
Normalize arena_palloc(), chunk_alloc_mmap_slow(), and
chunk_recycle_dss() to use the same algorithm for trimming
over-allocation.

Add the ALIGNMENT_ADDR2BASE(), ALIGNMENT_ADDR2OFFSET(), and
ALIGNMENT_CEILING() macros, and use them where appropriate.

Remove the run_size_p parameter from sa2u().

Fix a potential deadlock in chunk_recycle_dss() that was introduced by
eae269036c (Add alignment support to
chunk_alloc()).
2012-04-11 18:13:45 -07:00
Jason Evans
122449b073 Implement Valgrind support, redzones, and quarantine.
Implement Valgrind support, as well as the redzone and quarantine
features, which help Valgrind detect memory errors.  Redzones are only
implemented for small objects because the changes necessary to support
redzones around large and huge objects are complicated by in-place
reallocation, to the point that it isn't clear that the maintenance
burden is worth the incremental improvement to Valgrind support.

Merge arena_salloc() and arena_salloc_demote().

Refactor i[v]salloc() to expose the 'demote' option.
2012-04-11 11:46:18 -07:00
Jason Evans
fad100bc35 Remove arena_malloc_prechosen().
Remove arena_malloc_prechosen(), now that arena_malloc() can be invoked
in a way that is semantically equivalent.
2012-04-06 12:24:46 -07:00
Jason Evans
01b3fe55ff Add a0malloc(), a0calloc(), and a0free().
Add a0malloc(), a0calloc(), and a0free(), which are used by FreeBSD's
libc to allocate/deallocate TLS in static binaries.
2012-04-03 19:25:48 -07:00
Jason Evans
ae4c7b4b40 Clean up *PAGE* macros.
s/PAGE_SHIFT/LG_PAGE/g and s/PAGE_SIZE/PAGE/g.

Remove remnants of the dynamic-page-shift code.

Rename the "arenas.pagesize" mallctl to "arenas.page".

Remove the "arenas.chunksize" mallctl, which is redundant with
"opt.lg_chunk".
2012-04-02 07:04:34 -07:00
Jason Evans
09a0769ba7 Work around TLS deallocation via free().
glibc uses memalign()/free() to allocate/deallocate TLS, which means
that it is unsafe to set TLS variables as a side effect of free() --
they may already be deallocated.  Work around this by avoiding
tcache_create() within free().

Reported by Mike Hommey.
2012-03-30 12:11:03 -07:00
Jason Evans
cd9a1346e9 Implement tsd.
Implement tsd, which is a TLS/TSD abstraction that uses one or both
internally.  Modify bootstrapping such that no tsd's are utilized until
allocation is safe.

Remove malloc_[v]tprintf(), and use malloc_snprintf() instead.

Fix %p argument size handling in malloc_vsnprintf().

Fix a long-standing statistics-related bug in the "thread.arena"
mallctl that could cause crashes due to linked list corruption.
2012-03-23 15:14:55 -07:00
Jason Evans
4e2e3dd9cf Fix fork-related bugs.
Acquire/release arena bin locks as part of the prefork/postfork.  This
bug made deadlock in the child between fork and exec a possibility.

Split jemalloc_postfork() into jemalloc_postfork_{parent,child}() so
that the child can reinitialize mutexes rather than unlocking them.  In
practice, this bug tended not to cause problems.
2012-03-13 16:31:41 -07:00
Jason Evans
b172610317 Simplify small size class infrastructure.
Program-generate small size class tables for all valid combinations of
LG_TINY_MIN, LG_QUANTUM, and PAGE_SHIFT.  Use the appropriate table to generate
all relevant data structures, and remove the distinction between
tiny/quantum/cacheline/subpage bins.

Remove --enable-dynamic-page-shift.  This option didn't prove useful in
practice, and it prevented optimizations.

Add Tilera architecture support.
2012-02-28 16:50:47 -08:00
Jason Evans
746868929a Remove highruns statistics. 2012-02-13 15:18:19 -08:00
Jason Evans
ef8897b4b9 Make 8-byte tiny size class non-optional.
When tiny size class support was first added, it was intended to support
truly tiny size classes (even 2 bytes).  However, this wasn't very
useful in practice, so the minimum tiny size class has been limited to
sizeof(void *) for a long time now.  This is too small to be standards
compliant, but other commonly used malloc implementations do not even
bother using a 16-byte quantum  on systems with vector units (SSE2+,
AltiVEC, etc.).  As such, it is safe in practice to support an 8-byte
tiny size class on 64-bit systems that support 16-byte types.
2012-02-13 15:03:59 -08:00
Jason Evans
962463d9b5 Streamline tcache-related malloc/free fast paths.
tcache_get() is inlined, so do the config_tcache check inside
tcache_get() and simplify its callers.

Make arena_malloc() an inline function, since it is part of the malloc()
fast path.

Remove conditional logic that cause build issues if --disable-tcache was
specified.
2012-02-13 12:29:49 -08:00
Jason Evans
fd56043c53 Remove magic.
Remove structure magic, because 1) it is no longer conditional, and 2)
it stopped being very effective at detecting memory corruption several
years ago.
2012-02-13 10:24:43 -08:00
Jason Evans
7372b15a31 Reduce cpp conditional logic complexity.
Convert configuration-related cpp conditional logic to use static
constant variables, e.g.:

  #ifdef JEMALLOC_DEBUG
    [...]
  #endif

becomes:

  if (config_debug) {
    [...]
  }

The advantage is clearer, more concise code.  The main disadvantage is
that data structures no longer have conditionally defined fields, so
they pay the cost of all fields regardless of whether they are used.  In
practice, this is only a minor concern; config_stats will go away in an
upcoming change, and config_prof is the only other major feature that
depends on more than a few special-purpose fields.
2012-02-10 20:22:09 -08:00
Jason Evans
7427525c28 Move repo contents in jemalloc/ to top level. 2011-03-31 20:36:17 -07:00