765edd67b4
Refactor most of the decay-related functions to take as parameters the decay_t and associated extents_t structures to operate on. This prepares for supporting both lazy and forced purging on different decay schedules.
249 lines
6.6 KiB
C
249 lines
6.6 KiB
C
#ifndef JEMALLOC_INTERNAL_ARENA_STRUCTS_B_H
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#define JEMALLOC_INTERNAL_ARENA_STRUCTS_B_H
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/*
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* Read-only information associated with each element of arena_t's bins array
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* is stored separately, partly to reduce memory usage (only one copy, rather
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* than one per arena), but mainly to avoid false cacheline sharing.
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*
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* Each slab has the following layout:
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*
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* /--------------------\
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* | region 0 |
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* |--------------------|
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* | region 1 |
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* |--------------------|
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* | ... |
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* | ... |
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* | ... |
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* |--------------------|
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* | region nregs-1 |
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* \--------------------/
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*/
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struct arena_bin_info_s {
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/* Size of regions in a slab for this bin's size class. */
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size_t reg_size;
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/* Total size of a slab for this bin's size class. */
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size_t slab_size;
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/* Total number of regions in a slab for this bin's size class. */
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uint32_t nregs;
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/*
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* Metadata used to manipulate bitmaps for slabs associated with this
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* bin.
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*/
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bitmap_info_t bitmap_info;
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};
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struct arena_decay_s {
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/* Synchronizes all non-atomic fields. */
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malloc_mutex_t mtx;
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/*
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* Approximate time in seconds from the creation of a set of unused
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* dirty pages until an equivalent set of unused dirty pages is purged
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* and/or reused.
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*
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* Synchronization: atomic.
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*/
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ssize_t time;
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/* time / SMOOTHSTEP_NSTEPS. */
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nstime_t interval;
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/*
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* Time at which the current decay interval logically started. We do
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* not actually advance to a new epoch until sometime after it starts
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* because of scheduling and computation delays, and it is even possible
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* to completely skip epochs. In all cases, during epoch advancement we
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* merge all relevant activity into the most recently recorded epoch.
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*/
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nstime_t epoch;
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/* Deadline randomness generator. */
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uint64_t jitter_state;
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/*
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* Deadline for current epoch. This is the sum of interval and per
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* epoch jitter which is a uniform random variable in [0..interval).
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* Epochs always advance by precise multiples of interval, but we
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* randomize the deadline to reduce the likelihood of arenas purging in
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* lockstep.
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*/
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nstime_t deadline;
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/*
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* Number of dirty pages at beginning of current epoch. During epoch
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* advancement we use the delta between arena->decay.ndirty and
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* extents_npages_get(&arena->extents_cached) to determine how many
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* dirty pages, if any, were generated.
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*/
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size_t nunpurged;
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/*
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* Trailing log of how many unused dirty pages were generated during
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* each of the past SMOOTHSTEP_NSTEPS decay epochs, where the last
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* element is the most recent epoch. Corresponding epoch times are
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* relative to epoch.
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*/
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size_t backlog[SMOOTHSTEP_NSTEPS];
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};
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struct arena_bin_s {
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/* All operations on arena_bin_t fields require lock ownership. */
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malloc_mutex_t lock;
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/*
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* Current slab being used to service allocations of this bin's size
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* class. slabcur is independent of slabs_{nonfull,full}; whenever
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* slabcur is reassigned, the previous slab must be deallocated or
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* inserted into slabs_{nonfull,full}.
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*/
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extent_t *slabcur;
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/*
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* Heap of non-full slabs. This heap is used to assure that new
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* allocations come from the non-full slab that is oldest/lowest in
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* memory.
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*/
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extent_heap_t slabs_nonfull;
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/* List used to track full slabs. */
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extent_list_t slabs_full;
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/* Bin statistics. */
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malloc_bin_stats_t stats;
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};
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struct arena_s {
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/*
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* Number of threads currently assigned to this arena. Each thread has
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* two distinct assignments, one for application-serving allocation, and
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* the other for internal metadata allocation. Internal metadata must
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* not be allocated from arenas explicitly created via the arenas.create
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* mallctl, because the arena.<i>.reset mallctl indiscriminately
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* discards all allocations for the affected arena.
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*
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* 0: Application allocation.
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* 1: Internal metadata allocation.
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*
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* Synchronization: atomic.
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*/
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unsigned nthreads[2];
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/*
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* When percpu_arena is enabled, to amortize the cost of reading /
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* updating the current CPU id, track the most recent thread accessing
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* this arena, and only read CPU if there is a mismatch.
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*/
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tsdn_t *last_thd;
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/* Synchronization: internal. */
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arena_stats_t stats;
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/*
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* List of tcaches for extant threads associated with this arena.
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* Stats from these are merged incrementally, and at exit if
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* opt_stats_print is enabled.
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*
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* Synchronization: tcache_ql_mtx.
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*/
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ql_head(tcache_t) tcache_ql;
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malloc_mutex_t tcache_ql_mtx;
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/* Synchronization: internal. */
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prof_accum_t prof_accum;
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uint64_t prof_accumbytes;
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/*
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* PRNG state for cache index randomization of large allocation base
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* pointers.
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*
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* Synchronization: atomic.
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*/
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size_t offset_state;
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/*
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* Extent serial number generator state.
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*
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* Synchronization: atomic.
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*/
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size_t extent_sn_next;
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/* Synchronization: atomic. */
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dss_prec_t dss_prec;
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/*
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* Number of pages in active extents.
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*
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* Synchronization: atomic.
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*/
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size_t nactive;
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/*
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* Extant large allocations.
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*
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* Synchronization: large_mtx.
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*/
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extent_list_t large;
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/* Synchronizes all large allocation/update/deallocation. */
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malloc_mutex_t large_mtx;
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/*
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* Collections of extents that were previously allocated. These are
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* used when allocating extents, in an attempt to re-use address space.
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*
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* Synchronization: internal.
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*/
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extents_t extents_cached;
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extents_t extents_retained;
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/*
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* Decay-based purging state.
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*
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* Synchronization: internal.
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*/
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arena_decay_t decay;
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/*
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* True if a thread is currently executing arena_purge_to_limit().
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*
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* Synchronization: decay.mtx.
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*/
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bool purging;
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/*
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* Next extent size class in a growing series to use when satisfying a
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* request via the extent hooks (only if !config_munmap). This limits
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* the number of disjoint virtual memory ranges so that extent merging
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* can be effective even if multiple arenas' extent allocation requests
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* are highly interleaved.
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*
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* Synchronization: atomic.
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*/
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pszind_t extent_grow_next;
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/*
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* Freelist of extent structures that were allocated via base_alloc().
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*
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* Synchronization: extent_freelist_mtx.
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*/
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extent_list_t extent_freelist;
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malloc_mutex_t extent_freelist_mtx;
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/*
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* bins is used to store heaps of free regions.
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*
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* Synchronization: internal.
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*/
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arena_bin_t bins[NBINS];
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/*
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* Base allocator, from which arena metadata are allocated.
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*
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* Synchronization: internal.
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*/
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base_t *base;
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};
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/* Used in conjunction with tsd for fast arena-related context lookup. */
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struct arena_tdata_s {
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ticker_t decay_ticker;
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};
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#endif /* JEMALLOC_INTERNAL_ARENA_STRUCTS_B_H */
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