Commit Graph

37 Commits

Author SHA1 Message Date
David Goldblatt
a011c4c22d cache_bin: Separate out local and remote accesses.
This fixes an incorrect debug-mode assert:
- T1 starts an arena stats update and reads stack_head from another thread's
  cache bin, when that cache bin has 1 item in it.
- T2 allocates from that cache bin.  The cache_bin's stack_head now points to a
  NULL pointer, since the cache bin is empty.
- T1 Re-reads the cache_bin's stack_head to perform an assertion check (since it
  previously saw that the bin was empty, whatever stack_head points to should be
  non-NULL).
2021-01-08 14:18:08 -08:00
Yinan Zhang
be5e49f4fa Add a batch mode for cache_bin_alloc() 2020-11-16 20:58:01 -08:00
Yinan Zhang
566c4a8594 Slight changes to cache bin internal functions 2020-11-16 20:58:01 -08:00
Qi Wang
bf72188f80 Allow opt.tcache_max to accept small size classes.
Previously all the small size classes were cached.  However this has downsides
-- particularly when page size is greater than 4K (e.g. iOS), which will result
in much higher SMALL_MAXCLASS.

This change allows tcache_max to be set to lower values, to better control
resources taken by tcache.
2020-10-24 20:43:44 -07:00
David Goldblatt
ea51e97bb8 Add SEC module: a small extent cache.
This can be used to take pressure off a more centralized, worse-sharded
allocator without requiring a full break of the arena abstraction.
2020-10-23 11:14:34 -07:00
David Goldblatt
b58dea8d1b Cache bin: expose ncached_max publicly. 2020-05-16 13:34:23 -07:00
David Goldblatt
cd29ebefd0 Tcache: treat small and large cache bins uniformly 2020-04-14 15:20:19 -07:00
David Goldblatt
92485032b2 Cache bin: improve comments. 2020-03-12 11:54:19 -07:00
David Goldblatt
d701a085c2 Fast path: allow low-water mark changes.
This lets us put more allocations on an "almost as fast" path after a flush.
This results in around a 4% reduction in malloc cycles in prod workloads
(corresponding to about a 0.1% reduction in overall cycles).
2020-03-12 11:54:19 -07:00
David Goldblatt
397da03865 Cache bin: rewrite to track more state.
With this, we track all of the empty, full, and low water states together.  This
simplifies a lot of the tracking logic, since we now don't need the
cache_bin_info_t for state queries (except for some debugging).
2020-03-12 11:54:19 -07:00
David Goldblatt
d498a4bb08 Cache bin: Add an emptiness assertion. 2020-03-12 11:54:19 -07:00
David Goldblatt
6a7aa46ef7 Cache bin: Add a debug method for init checking. 2020-03-12 11:54:19 -07:00
David Goldblatt
370c1ea007 Cache bin: Write the unit test in terms of the API
I.e. stop allowing the unit test to have secret access to implementation
internals.
2020-03-12 11:54:19 -07:00
David Goldblatt
7f5ebd211c Cache bin: set low-water internally. 2020-03-12 11:54:19 -07:00
David Goldblatt
60113dfe3b Cache bin: Move in initialization code. 2020-03-12 11:54:19 -07:00
David Goldblatt
44529da852 Cache-bin: Make flush modifications internal
I.e. the tcache code just calls a cache-bin function to finish flush (and move
pointers around, etc.).  It doesn't directly access the cache-bin's owned memory
any more.
2020-03-12 11:54:19 -07:00
David Goldblatt
ff6acc6ed5 Cache bin: simplify names and argument ordering.
We always start with the cache bin, then its info (if necessary).
2020-03-12 11:54:19 -07:00
David Goldblatt
e1dcc557d6 Cache bin: Only take the relevant cache_bin_info_t
Previously, we took an array of cache_bin_info_ts and an index, and dereferenced
ourselves.  But infos for other cache_bins aren't relevant to any particular
cache bin, so that should be the caller's job.
2020-03-12 11:54:19 -07:00
David Goldblatt
1b00d808d7 cache_bin: Don't let arena see empty position. 2020-03-12 11:54:19 -07:00
David Goldblatt
d303f30796 cache_bin nflush -> n.
We're going to use it on the fill pathway as well.
2020-03-12 11:54:19 -07:00
David Goldblatt
74d36d78ef Cache bin: Make ncached_max a query on the info_t. 2020-03-12 11:54:19 -07:00
David Goldblatt
b66c0973cc cache_bin: Don't allow direct internals access. 2020-03-12 11:54:19 -07:00
David Goldblatt
909c501b07 Cache_bin: Shouldn't know about tcache.
Instead, have it take the cache_bin_info_ts to use by pointer.  While we're
here, add a src file for the cache bin.
2020-03-12 11:54:19 -07:00
David T. Goldblatt
34b7165fde Put szind_t, pszind_t in sz.h. 2020-02-18 11:22:09 -08:00
Yinan Zhang
05681e387a Optimize cache_bin_alloc_easy for malloc fast path
`tcache_bin_info` is not accessed on malloc fast path but the
compiler reserves a register for it, as well as an additional
register for `tcache_bin_info[ind].stack_size`.  The optimization
gets rid of the need for the two registers.
2019-10-21 16:43:45 -07:00
Yinan Zhang
4fe50bc7d0 Fix amd64 MSVC warning 2019-10-18 10:16:29 -07:00
Qi Wang
785b84e603 Make cache_bin_sz_t unsigned.
The bin size type was made signed only because the low_water could go -1, which
was already removed.
2019-09-04 13:37:07 -07:00
Qi Wang
23dc7a7fba Fix index type for cache_bin_alloc_easy. 2019-09-04 13:37:07 -07:00
Qi Wang
0043e68d4c Track low_water == -1 case explicitly.
The -1 value of low_water indicates if the cache has been depleted and
refilled.  Track the status explicitly in the tcache struct.

This allows the fast path to check if (cur_ptr > low_water), instead of >=,
which avoids reaching slow path when the last item is allocated.
2019-08-21 16:00:38 -07:00
Qi Wang
937ca1db9f Store ncached_max * ptr_size in tcache_bin_info.
With the cache bin metadata switched to pointers, ncached_max is usually
accessed and timed by sizeof(ptr). Store the results in tcache_bin_info for
direct access, and add a helper function for the ncached_max value.
2019-08-19 12:23:24 -07:00
Qi Wang
7599c82d48 Redesign the cache bin metadata for fast path.
Implement the pointer-based metadata for tcache bins --
- 3 pointers are maintained to represent each bin;
- 2 of the pointers are compressed on 64-bit;
- is_full / is_empty done through pointer comparison;

Comparing to the previous counter based design --
- fast-path speed up ~15% in benchmarks
- direct pointer comparison and de-reference
- no need to access tcache_bin_info in common case
2019-08-19 12:21:44 -07:00
Dave Watson
e2ab215324 refactor tcache_dalloc_small
Add a cache_bin_dalloc_easy (to match the alloc_easy function),
and use it in tcache_dalloc_small.  It will also be used in the
new free fastpath.
2018-11-12 13:20:37 -08:00
Dave Watson
09adf18f1a Remove a branch from cache_bin_alloc_easy
Combine the branches for checking for an empty cache_bin, and
checking for the low watermark.
2018-10-15 08:18:15 -07:00
David T. Goldblatt
901d94a2b0 Rename cache_alloc_easy to cache_bin_alloc_easy.
This lives in the cache_bin module; just a typo.
2017-12-18 16:29:10 -08:00
David Goldblatt
ea91dfa58e Document the ialloc function abbreviations.
In the jemalloc_internal_inlines files, we have a lot of somewhat terse function
names.  This commit adds some documentation to aid in translation.
2017-08-16 17:48:44 -07:00
David Goldblatt
9c0549007d Make arena stats collection go through cache bins.
This eliminates the need for the arena stats code to "know" about tcaches; all
that it needs is a cache_bin_array_descriptor_t to tell it where to find
cache_bins whose stats it should aggregate.
2017-08-16 17:48:44 -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