Commit Graph

65 Commits

Author SHA1 Message Date
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