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#ifndef JEMALLOC_INTERNAL_EXTENT_STRUCTS_H
#define JEMALLOC_INTERNAL_EXTENT_STRUCTS_H
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/bitmap.h"
#include "jemalloc/internal/mutex.h"
#include "jemalloc/internal/ql.h"
#include "jemalloc/internal/ph.h"
#include "jemalloc/internal/size_classes.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
* d: dumpable
* z: zeroed
* t: state
* i: szind
* f: nfree
* n: sn
*
* nnnnnnnn ... nnnnffff ffffffii iiiiiitt zdcbaaaa 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.
*
* dumpable: The dumpable flag indicates whether or not we've set the
* memory in question to be dumpable. Note that this
* interacts somewhat subtly with user-specified extent hooks,
* since we don't know if *they* are fiddling with
* dumpability (in which case, we don't want to undo whatever
* they're doing). To deal with this scenario, we:
* - Make dumpable false only for memory allocated with the
* default hooks.
* - Only allow memory to go from non-dumpable to dumpable,
* and only once.
* - Never make the OS call to allow dumping when the
* dumpable bit is already set.
* These three constraints mean that we will never
* accidentally dump user memory that the user meant to set
* nondumpable with their extent hooks.
*
*
* 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 sz_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 !opt_retain, 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 MASK(CURRENT_FIELD_WIDTH, CURRENT_FIELD_SHIFT) ((((((uint64_t)0x1U) << (CURRENT_FIELD_WIDTH)) - 1)) << (CURRENT_FIELD_SHIFT))
#define EXTENT_BITS_ARENA_WIDTH MALLOCX_ARENA_BITS
#define EXTENT_BITS_ARENA_SHIFT 0
#define EXTENT_BITS_ARENA_MASK MASK(EXTENT_BITS_ARENA_WIDTH, EXTENT_BITS_ARENA_SHIFT)
#define EXTENT_BITS_SLAB_WIDTH 1
#define EXTENT_BITS_SLAB_SHIFT (EXTENT_BITS_ARENA_WIDTH + EXTENT_BITS_ARENA_SHIFT)
#define EXTENT_BITS_SLAB_MASK MASK(EXTENT_BITS_SLAB_WIDTH, EXTENT_BITS_SLAB_SHIFT)
#define EXTENT_BITS_COMMITTED_WIDTH 1
#define EXTENT_BITS_COMMITTED_SHIFT (EXTENT_BITS_SLAB_WIDTH + EXTENT_BITS_SLAB_SHIFT)
#define EXTENT_BITS_COMMITTED_MASK MASK(EXTENT_BITS_COMMITTED_WIDTH, EXTENT_BITS_COMMITTED_SHIFT)
#define EXTENT_BITS_DUMPABLE_WIDTH 1
#define EXTENT_BITS_DUMPABLE_SHIFT (EXTENT_BITS_COMMITTED_WIDTH + EXTENT_BITS_COMMITTED_SHIFT)
#define EXTENT_BITS_DUMPABLE_MASK MASK(EXTENT_BITS_DUMPABLE_WIDTH, EXTENT_BITS_DUMPABLE_SHIFT)
#define EXTENT_BITS_ZEROED_WIDTH 1
#define EXTENT_BITS_ZEROED_SHIFT (EXTENT_BITS_DUMPABLE_WIDTH + EXTENT_BITS_DUMPABLE_SHIFT)
#define EXTENT_BITS_ZEROED_MASK MASK(EXTENT_BITS_ZEROED_WIDTH, EXTENT_BITS_ZEROED_SHIFT)
#define EXTENT_BITS_STATE_WIDTH 2
#define EXTENT_BITS_STATE_SHIFT (EXTENT_BITS_ZEROED_WIDTH + EXTENT_BITS_ZEROED_SHIFT)
#define EXTENT_BITS_STATE_MASK MASK(EXTENT_BITS_STATE_WIDTH, EXTENT_BITS_STATE_SHIFT)
#define EXTENT_BITS_SZIND_WIDTH LG_CEIL_NSIZES
#define EXTENT_BITS_SZIND_SHIFT (EXTENT_BITS_STATE_WIDTH + EXTENT_BITS_STATE_SHIFT)
#define EXTENT_BITS_SZIND_MASK MASK(EXTENT_BITS_SZIND_WIDTH, EXTENT_BITS_SZIND_SHIFT)
#define EXTENT_BITS_NFREE_WIDTH (LG_SLAB_MAXREGS + 1)
#define EXTENT_BITS_NFREE_SHIFT (EXTENT_BITS_SZIND_WIDTH + EXTENT_BITS_SZIND_SHIFT)
#define EXTENT_BITS_NFREE_MASK MASK(EXTENT_BITS_NFREE_WIDTH, EXTENT_BITS_NFREE_SHIFT)
#define EXTENT_BITS_SN_SHIFT (EXTENT_BITS_NFREE_WIDTH + EXTENT_BITS_NFREE_SHIFT)
#define EXTENT_BITS_SN_MASK (UINT64_MAX << EXTENT_BITS_SN_SHIFT)
/* Pointer to the extent that this structure is responsible for. */
void *e_addr;
union {
/*
* Extent size and serial number associated with the extent
* structure (different than the serial number for the extent at
* e_addr).
*
* ssssssss [...] ssssssss ssssnnnn nnnnnnnn
*/
size_t e_size_esn;
#define EXTENT_SIZE_MASK ((size_t)~(PAGE-1))
#define EXTENT_ESN_MASK ((size_t)PAGE-1)
/* Base extent size, which may not be a multiple of PAGE. */
size_t e_bsize;
};
/*
* List linkage, used by a variety of lists:
* - bin_t's slabs_full
* - extents_t's LRU
* - stashed dirty extents
* - arena's large allocations
*/
ql_elm(extent_t) ql_link;
/*
* Linkage for per size class sn/address-ordered heaps, and
* for extent_avail
*/
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_tree_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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