#ifndef JEMALLOC_INTERNAL_ARENA_STRUCTS_B_H
#define JEMALLOC_INTERNAL_ARENA_STRUCTS_B_H
/*
 * Read-only information associated with each element of arena_t's bins array
 * is stored separately, partly to reduce memory usage (only one copy, rather
 * than one per arena), but mainly to avoid false cacheline sharing.
 *
 * Each slab has the following layout:
 *
 *   /--------------------\
 *   | region 0           |
 *   |--------------------|
 *   | region 1           |
 *   |--------------------|
 *   | ...                |
 *   | ...                |
 *   | ...                |
 *   |--------------------|
 *   | region nregs-1     |
 *   \--------------------/
 */
struct arena_bin_info_s {
	/* Size of regions in a slab for this bin's size class. */
	size_t			reg_size;

	/* Total size of a slab for this bin's size class. */
	size_t			slab_size;

	/* Total number of regions in a slab for this bin's size class. */
	uint32_t		nregs;

	/*
	 * Metadata used to manipulate bitmaps for slabs associated with this
	 * bin.
	 */
	bitmap_info_t		bitmap_info;
};

typedef union {
	size_t			u; /* Used for atomic operations. */
	ssize_t			s; /* Time may be negative (means "never"). */
} arena_decay_time_t;

struct arena_decay_s {
	/* Synchronizes all non-atomic fields. */
	malloc_mutex_t		mtx;
	/*
	 * Approximate time in seconds from the creation of a set of unused
	 * dirty pages until an equivalent set of unused dirty pages is purged
	 * and/or reused.
	 *
	 * Synchronization: atomic.
	 */
	arena_decay_time_t	time;
	/* time / SMOOTHSTEP_NSTEPS. */
	nstime_t		interval;
	/*
	 * Time at which the current decay interval logically started.  We do
	 * not actually advance to a new epoch until sometime after it starts
	 * because of scheduling and computation delays, and it is even possible
	 * to completely skip epochs.  In all cases, during epoch advancement we
	 * merge all relevant activity into the most recently recorded epoch.
	 */
	nstime_t		epoch;
	/* Deadline randomness generator. */
	uint64_t		jitter_state;
	/*
	 * Deadline for current epoch.  This is the sum of interval and per
	 * epoch jitter which is a uniform random variable in [0..interval).
	 * Epochs always advance by precise multiples of interval, but we
	 * randomize the deadline to reduce the likelihood of arenas purging in
	 * lockstep.
	 */
	nstime_t		deadline;
	/*
	 * Number of dirty pages at beginning of current epoch.  During epoch
	 * advancement we use the delta between arena->decay.ndirty and
	 * extents_npages_get(&arena->extents_cached) to determine how many
	 * dirty pages, if any, were generated.
	 */
	size_t			nunpurged;
	/*
	 * Trailing log of how many unused dirty pages were generated during
	 * each of the past SMOOTHSTEP_NSTEPS decay epochs, where the last
	 * element is the most recent epoch.  Corresponding epoch times are
	 * relative to epoch.
	 */
	size_t			backlog[SMOOTHSTEP_NSTEPS];
};

struct arena_bin_s {
	/* All operations on arena_bin_t fields require lock ownership. */
	malloc_mutex_t		lock;

	/*
	 * Current slab being used to service allocations of this bin's size
	 * class.  slabcur is independent of slabs_{nonfull,full}; whenever
	 * slabcur is reassigned, the previous slab must be deallocated or
	 * inserted into slabs_{nonfull,full}.
	 */
	extent_t		*slabcur;

	/*
	 * Heap of non-full slabs.  This heap is used to assure that new
	 * allocations come from the non-full slab that is oldest/lowest in
	 * memory.
	 */
	extent_heap_t		slabs_nonfull;

	/* List used to track full slabs. */
	extent_list_t		slabs_full;

	/* Bin statistics. */
	malloc_bin_stats_t	stats;
};

struct arena_s {
	/*
	 * Number of threads currently assigned to this arena.  Each thread has
	 * two distinct assignments, one for application-serving allocation, and
	 * the other for internal metadata allocation.  Internal metadata must
	 * not be allocated from arenas explicitly created via the arenas.create
	 * mallctl, because the arena.<i>.reset mallctl indiscriminately
	 * discards all allocations for the affected arena.
	 *
	 *   0: Application allocation.
	 *   1: Internal metadata allocation.
	 *
	 * Synchronization: atomic.
	 */
	unsigned		nthreads[2];

	/* Synchronization: internal. */
	arena_stats_t		stats;

	/*
	 * List of tcaches for extant threads associated with this arena.
	 * Stats from these are merged incrementally, and at exit if
	 * opt_stats_print is enabled.
	 *
	 * Synchronization: tcache_ql_mtx.
	 */
	ql_head(tcache_t)	tcache_ql;
	malloc_mutex_t		tcache_ql_mtx;

	/* Synchronization: internal. */
	prof_accum_t		prof_accum;
	uint64_t		prof_accumbytes;

	/*
	 * PRNG state for cache index randomization of large allocation base
	 * pointers.
	 *
	 * Synchronization: atomic.
	 */
	size_t			offset_state;

	/*
	 * Extent serial number generator state.
	 *
	 * Synchronization: atomic.
	 */
	size_t			extent_sn_next;

	/* Synchronization: atomic. */
	dss_prec_t		dss_prec;

	/*
	 * 1/0 (true/false) if a thread is currently executing
	 * arena_purge_to_limit().
	 *
	 * Synchronization: atomic.
	 */
	unsigned		purging;

	/*
	 * Number of pages in active extents.
	 *
	 * Synchronization: atomic.
	 */
	size_t			nactive;

	/*
	 * Decay-based purging state.
	 *
	 * Synchronization: lock.
	 */
	arena_decay_t		decay;

	/*
	 * Extant large allocations.
	 *
	 * Synchronization: large_mtx.
	 */
	extent_list_t		large;
	/* Synchronizes all large allocation/update/deallocation. */
	malloc_mutex_t		large_mtx;

	/*
	 * Collections of extents that were previously allocated.  These are
	 * used when allocating extents, in an attempt to re-use address space.
	 *
	 * Synchronization: internal.
	 */
	extents_t		extents_cached;
	extents_t		extents_retained;

	/*
	 * Next extent size class in a growing series to use when satisfying a
	 * request via the extent hooks (only if !config_munmap).  This limits
	 * the number of disjoint virtual memory ranges so that extent merging
	 * can be effective even if multiple arenas' extent allocation requests
	 * are highly interleaved.
	 *
	 * Synchronization: atomic.
	 */
	pszind_t		extent_grow_next;

	/*
	 * Freelist of extent structures that were allocated via base_alloc().
	 *
	 * Synchronization: extent_freelist_mtx.
	 */
	extent_list_t		extent_freelist;
	malloc_mutex_t		extent_freelist_mtx;

	/*
	 * bins is used to store heaps of free regions.
	 *
	 * Synchronization: internal.
	 */
	arena_bin_t		bins[NBINS];

	/*
	 * Base allocator, from which arena metadata are allocated.
	 *
	 * Synchronization: internal.
	 */
	base_t			*base;
};

/* Used in conjunction with tsd for fast arena-related context lookup. */
struct arena_tdata_s {
	ticker_t		decay_ticker;
};

#endif /* JEMALLOC_INTERNAL_ARENA_STRUCTS_B_H */