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#ifndef JEMALLOC_INTERNAL_EXTENT_STRUCTS_H
#define JEMALLOC_INTERNAL_EXTENT_STRUCTS_H
#include "jemalloc/internal/ph.h"
typedef enum {
extent_state_active = 0,
extent_state_dirty = 1,
extent_state_muzzy = 2,
extent_state_retained = 3
} extent_state_t;
/* Extent (span of pages). Use accessor functions for e_* fields. */
struct extent_s {
/*
* Bitfield containing several fields:
*
* a: arena_ind
* b: slab
* c: committed
* z: zeroed
* t: state
* i: szind
* n: sn
* f: nfree
*
* nnnnnnnn ... nnnnnfff fffffffi iiiiiiit tzcbaaaa aaaaaaaa
*
* arena_ind: Arena from which this extent came, or all 1 bits if
* unassociated.
*
* slab: The slab flag indicates whether the extent is used for a slab
* of small regions. This helps differentiate small size classes,
* and it indicates whether interior pointers can be looked up via
* iealloc().
*
* committed: The committed flag indicates whether physical memory is
* committed to the extent, whether explicitly or implicitly
* as on a system that overcommits and satisfies physical
* memory needs on demand via soft page faults.
*
* zeroed: The zeroed flag is used by extent recycling code to track
* whether memory is zero-filled.
*
* state: The state flag is an extent_state_t.
*
* szind: The szind flag indicates usable size class index for
* allocations residing in this extent, regardless of whether the
* extent is a slab. Extent size and usable size often differ
* even for non-slabs, either due to large_pad or promotion of
* sampled small regions.
*
* nfree: Number of free regions in slab.
*
* sn: Serial number (potentially non-unique).
*
* Serial numbers may wrap around if JEMALLOC_MUNMAP is defined, but
* as long as comparison functions fall back on address comparison
* for equal serial numbers, stable (if imperfect) ordering is
* maintained.
*
* Serial numbers may not be unique even in the absence of
* wrap-around, e.g. when splitting an extent and assigning the same
* serial number to both resulting adjacent extents.
*/
uint64_t e_bits;
#define EXTENT_BITS_ARENA_SHIFT 0
#define EXTENT_BITS_ARENA_MASK \
(((uint64_t)(1U << MALLOCX_ARENA_BITS) - 1) << EXTENT_BITS_ARENA_SHIFT)
#define EXTENT_BITS_SLAB_SHIFT MALLOCX_ARENA_BITS
#define EXTENT_BITS_SLAB_MASK \
((uint64_t)0x1U << EXTENT_BITS_SLAB_SHIFT)
#define EXTENT_BITS_COMMITTED_SHIFT (MALLOCX_ARENA_BITS + 1)
#define EXTENT_BITS_COMMITTED_MASK \
((uint64_t)0x1U << EXTENT_BITS_COMMITTED_SHIFT)
#define EXTENT_BITS_ZEROED_SHIFT (MALLOCX_ARENA_BITS + 2)
#define EXTENT_BITS_ZEROED_MASK \
((uint64_t)0x1U << EXTENT_BITS_ZEROED_SHIFT)
#define EXTENT_BITS_STATE_SHIFT (MALLOCX_ARENA_BITS + 3)
#define EXTENT_BITS_STATE_MASK \
((uint64_t)0x3U << EXTENT_BITS_STATE_SHIFT)
#define EXTENT_BITS_SZIND_SHIFT (MALLOCX_ARENA_BITS + 5)
#define EXTENT_BITS_SZIND_MASK \
(((uint64_t)(1U << LG_CEIL_NSIZES) - 1) << EXTENT_BITS_SZIND_SHIFT)
#define EXTENT_BITS_NFREE_SHIFT \
(MALLOCX_ARENA_BITS + 5 + LG_CEIL_NSIZES)
#define EXTENT_BITS_NFREE_MASK \
((uint64_t)((1U << (LG_SLAB_MAXREGS + 1)) - 1) << EXTENT_BITS_NFREE_SHIFT)
#define EXTENT_BITS_SN_SHIFT \
(MALLOCX_ARENA_BITS + 5 + LG_CEIL_NSIZES + (LG_SLAB_MAXREGS + 1))
#define EXTENT_BITS_SN_MASK (UINT64_MAX << EXTENT_BITS_SN_SHIFT)
/* Pointer to the extent that this structure is responsible for. */
void *e_addr;
/* Extent size. */
size_t e_size;
/*
* List linkage, used by a variety of lists:
* - arena_bin_t's slabs_full
* - extents_t's LRU
* - stashed dirty extents
* - arena's large allocations
* - arena's extent structure freelist
*/
ql_elm(extent_t) ql_link;
/* Linkage for per size class sn/address-ordered heaps. */
phn(extent_t) ph_link;
union {
/* Small region slab metadata. */
arena_slab_data_t e_slab_data;
/*
* Profile counters, used for large objects. Points to a
* prof_tctx_t.
*/
atomic_p_t e_prof_tctx;
};
};
typedef ql_head(extent_t) extent_list_t;
typedef ph(extent_t) extent_heap_t;
/* Quantized collection of extents, with built-in LRU queue. */
struct extents_s {
malloc_mutex_t mtx;
/*
* Quantized per size class heaps of extents.
*
* Synchronization: mtx.
*/
extent_heap_t heaps[NPSIZES+1];
/*
* Bitmap for which set bits correspond to non-empty heaps.
*
* Synchronization: mtx.
*/
bitmap_t bitmap[BITMAP_GROUPS(NPSIZES+1)];
/*
* LRU of all extents in heaps.
*
* Synchronization: mtx.
*/
extent_list_t lru;
/*
* Page sum for all extents in heaps.
*
* The synchronization here is a little tricky. Modifications to npages
* must hold mtx, but reads need not (though, a reader who sees npages
* without holding the mutex can't assume anything about the rest of the
* state of the extents_t).
*/
atomic_zu_t npages;
/* All stored extents must be in the same state. */
extent_state_t state;
/*
* If true, delay coalescing until eviction; otherwise coalesce during
* deallocation.
*/
bool delay_coalesce;
};
#endif /* JEMALLOC_INTERNAL_EXTENT_STRUCTS_H */
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