Commit Graph

35 Commits

Author SHA1 Message Date
Qi Wang
37b8913925 Add support for sharded bins within an 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.
2018-12-03 17:17:03 -08:00
Tyler Etzel
c14e6c0819 Add extents information to mallocstats output
- Show number/bytes of extents of each size that are dirty, muzzy, retained.
2018-08-02 10:16:06 -07:00
David Goldblatt
3aba072cef SC: Remove global data.
The global data is mostly only used at initialization, or for easy access to
values we could compute statically.  Instead of consuming that space (and
risking TLB misses), we can just pass around a pointer to stack data during
bootstrapping.
2018-07-23 13:37:08 -07:00
David Goldblatt
e904f813b4 Hide size class computation behind a layer of indirection.
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.
2018-07-12 20:53:06 -07:00
Qi Wang
94a88c26f4 Implement huge arena: opt.huge_threshold.
The feature allows using a dedicated arena for huge allocations.  We want the
addtional arena to separate huge allocation because: 1) mixing small extents
with huge ones causes fragmentation over the long run (this feature reduces VM
size significantly); 2) with many arenas, huge extents rarely get reused across
threads; and 3) huge allocations happen way less frequently, therefore no
concerns for lock contention.
2018-06-29 10:35:02 -07:00
Qi Wang
0ff7ff3ec7 Optimize ixalloc by avoiding a size lookup. 2018-06-05 21:03:51 -07:00
David Goldblatt
cb0707c0fc Hooks: hook the realloc pathways that move/expand. 2018-05-18 11:43:03 -07:00
David T. Goldblatt
7f1b02e3fa Split up and standardize naming of stats code.
The arena-associated stats are now all prefixed with arena_stats_, and live in
their own file.  Likewise, malloc_bin_stats_t -> bin_stats_t, also in its own
file.
2017-12-18 16:29:10 -08:00
David T. Goldblatt
4bf4a1c4ea Pull out arena_bin_info_t and arena_bin_t into their own file.
In the process, kill arena_bin_index, which is unused.  To follow are several
diffs continuing this separation.
2017-12-18 16:29:10 -08:00
Qi Wang
e422fa8e7e Add arena.i.retain_grow_limit
This option controls the max size when grow_retained.  This is useful when we
have customized extent hooks reserving physical memory (e.g. 1G huge pages).
Without this feature, the default increasing sequence could result in fragmented
and wasted physical memory.
2017-11-03 13:53:33 -07:00
David Goldblatt
f3170baa30 Pull out caching for a bin into its own file.
This is the first step towards breaking up the tcache and arena (since they
interact primarily at the bin level).  It should also make a future arena
caching implementation more straightforward.
2017-08-16 17:48:44 -07:00
Qi Wang
cb032781bd Add extent_grow_mtx in pre_ / post_fork handlers.
This fixed the issue that could cause the child process to stuck after fork.
2017-06-29 17:01:18 -07:00
Qi Wang
73713fbb27 Drop high rank locks when creating threads.
Avoid holding arenas_lock and background_thread_lock when creating background
threads, because pthread_create may take internal locks, and potentially cause
deadlock with jemalloc internal locks.
2017-06-08 10:02:18 -07:00
Jason Evans
b511232fcd Refactor/fix background_thread/percpu_arena bootstrapping.
Refactor bootstrapping such that dlsym() is called during the
bootstrapping phase that can tolerate reentrant allocation.
2017-06-01 08:55:27 -07:00
David Goldblatt
8261e581be Header refactoring: Pull size helpers out of jemalloc module. 2017-05-31 13:08:45 -07:00
David Goldblatt
93284bb53d Header refactoring: unify and de-catchall extent_dss. 2017-05-31 13:08:45 -07:00
Qi Wang
b693c7868e Implementing opt.background_thread.
Added opt.background_thread to enable background threads, which handles purging
currently.  When enabled, decay ticks will not trigger purging (which will be
left to the background threads).  We limit the max number of threads to NCPUs.
When percpu arena is enabled, set CPU affinity for the background threads as
well.

The sleep interval of background threads is dynamic and determined by computing
number of pages to purge in the future (based on backlog).
2017-05-23 12:26:20 -07:00
Jason Evans
6e62c62862 Refactor *decay_time into *decay_ms.
Support millisecond resolution for decay times.  Among other use cases
this makes it possible to specify a short initial dirty-->muzzy decay
phase, followed by a longer muzzy-->clean decay phase.

This resolves #812.
2017-05-18 11:33:45 -07:00
Jason Evans
a268af5085 Stop depending on JEMALLOC_N() for function interception during testing.
Instead, always define function pointers for interceptable functions,
but mark them const unless testing, so that the compiler can optimize
out the pointer dereferences.
2017-05-11 23:06:54 -07:00
David Goldblatt
268843ac68 Header refactoring: pages.h - unify and remove from catchall. 2017-04-25 09:51:38 -07:00
David Goldblatt
d6b5c7e0f6 Header refactoring: stats - unify and remove from catchall 2017-04-24 10:33:21 -07:00
David Goldblatt
31b43219db Header refactoring: size_classes module - remove from the catchall 2017-04-24 10:33:21 -07:00
Qi Wang
36bd90b962 Optimizing TSD and thread cache layout.
1) Re-organize TSD so that frequently accessed fields are closer to the
beginning and more compact.  Assuming 64-bit, the first 2.5 cachelines now
contains everything needed on tcache fast path, expect the tcache struct itself.

2) Re-organize tcache and tbins.  Take lg_fill_div out of tbin, and reduce tbin
to 24 bytes (down from 32). Split tbins into tbins_small and tbins_large, and
place tbins_small close to the beginning.
2017-04-07 14:06:17 -07:00
Jason Evans
5e67fbc367 Push down iealloc() calls.
Call iealloc() as deep into call chains as possible without causing
redundant calls.
2017-03-22 18:33:32 -07:00
Jason Evans
64e458f5cd Implement two-phase decay-based purging.
Split decay-based purging into two phases, the first of which uses lazy
purging to convert dirty pages to "muzzy", and the second of which uses
forced purging, decommit, or unmapping to convert pages to clean or
destroy them altogether.  Not all operating systems support lazy
purging, yet the application may provide extent hooks that implement
lazy purging, so care must be taken to dynamically omit the first phase
when necessary.

The mallctl interfaces change as follows:
- opt.decay_time --> opt.{dirty,muzzy}_decay_time
- arena.<i>.decay_time --> arena.<i>.{dirty,muzzy}_decay_time
- arenas.decay_time --> arenas.{dirty,muzzy}_decay_time
- stats.arenas.<i>.pdirty --> stats.arenas.<i>.p{dirty,muzzy}
- stats.arenas.<i>.{npurge,nmadvise,purged} -->
  stats.arenas.<i>.{dirty,muzzy}_{npurge,nmadvise,purged}

This resolves #521.
2017-03-15 13:13:47 -07:00
Qi Wang
ec532e2c5c Implement per-CPU arena.
The new feature, opt.percpu_arena, determines thread-arena association
dynamically based CPU id. Three modes are supported: "percpu", "phycpu"
and disabled.

"percpu" uses the current core id (with help from sched_getcpu())
directly as the arena index, while "phycpu" will assign threads on the
same physical CPU to the same arena. In other words, "percpu" means # of
arenas == # of CPUs, while "phycpu" has # of arenas == 1/2 * (# of
CPUs). Note that no runtime check on whether hyper threading is enabled
is added yet.

When enabled, threads will be migrated between arenas when a CPU change
is detected. In the current design, to reduce overhead from reading CPU
id, each arena tracks the thread accessed most recently. When a new
thread comes in, we will read CPU id and update arena if necessary.
2017-03-08 23:19:01 -08:00
Qi Wang
8721e19c04 Fix arena_prefork lock rank order for witness.
When witness is enabled, lock rank order needs to be preserved during
prefork, not only for each arena, but also across arenas. This change
breaks arena_prefork into further stages to ensure valid rank order
across arenas. Also changed test/unit/fork to use a manual arena to
catch this case.
2017-03-08 23:07:27 -08:00
Jason Evans
fd058f572b Immediately purge cached extents if decay_time is 0.
This fixes a regression caused by
54269dc0ed (Remove obsolete
arena_maybe_purge() call.), as well as providing a general fix.

This resolves #665.
2017-03-02 19:43:06 -08:00
Jason Evans
d61a5f76b2 Convert arena_decay_t's time to be atomically synchronized. 2017-03-02 19:43:06 -08:00
Jason Evans
003ca8717f Move arena_basic_stats_merge() prototype (hygienic cleanup). 2017-02-21 12:46:20 -08:00
Jason Evans
b0654b95ed Fix arena->stats.mapped accounting.
Mapped memory increases when extent_alloc_wrapper() succeeds, and
decreases when extent_dalloc_wrapper() is called (during purging).
2017-02-16 15:52:11 -08:00
Jason Evans
6b5cba4191 Convert arena->stats synchronization to atomics. 2017-02-16 09:39:46 -08:00
Jason Evans
b779522b9b Convert arena->dss_prec synchronization to atomics. 2017-02-16 09:39:46 -08:00
Jason Evans
d27f29b468 Disentangle arena and extent locking.
Refactor arena and extent locking protocols such that arena and
extent locks are never held when calling into the extent_*_wrapper()
API.  This requires extra care during purging since the arena lock no
longer protects the inner purging logic.  It also requires extra care to
protect extents from being merged with adjacent extents.

Convert extent_t's 'active' flag to an enumerated 'state', so that
retained extents are explicitly marked as such, rather than depending on
ring linkage state.

Refactor the extent collections (and their synchronization) for cached
and retained extents into extents_t.  Incorporate LRU functionality to
support purging.  Incorporate page count accounting, which replaces
arena->ndirty and arena->stats.retained.

Assert that no core locks are held when entering any internal
[de]allocation functions.  This is in addition to existing assertions
that no locks are held when entering external [de]allocation functions.

Audit and document synchronization protocols for all arena_t fields.

This fixes a potential deadlock due to recursive allocation during
gdump, in a similar fashion to b49c649bc1
(Fix lock order reversal during gdump.), but with a necessarily much
broader code impact.
2017-02-01 16:43:46 -08:00
David Goldblatt
77cccac8cd Break up headers into constituent parts
This is part of a broader change to make header files better represent the
dependencies between one another (see
https://github.com/jemalloc/jemalloc/issues/533). It breaks up component headers
into smaller parts that can be made to have a simpler dependency graph.

For the autogenerated headers (smoothstep.h and size_classes.h), no splitting
was necessary, so I didn't add support to emit multiple headers.
2017-01-12 15:43:51 -08:00