5d33233a5e
Rather than iteratively checking all sufficiently large heaps during search, maintain and use a bitmap in order to skip empty heaps.
140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
#ifndef JEMALLOC_INTERNAL_EXTENT_STRUCTS_H
|
|
#define JEMALLOC_INTERNAL_EXTENT_STRUCTS_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 {
|
|
/* Arena from which this extent came, if any. */
|
|
arena_t *e_arena;
|
|
|
|
/* Pointer to the extent that this structure is responsible for. */
|
|
void *e_addr;
|
|
|
|
/* Extent size. */
|
|
size_t e_size;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
szind_t e_szind;
|
|
|
|
/*
|
|
* Serial number (potentially non-unique).
|
|
*
|
|
* In principle serial numbers can wrap around on 32-bit systems 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.
|
|
*/
|
|
size_t e_sn;
|
|
|
|
/* Extent state. */
|
|
extent_state_t e_state;
|
|
|
|
/*
|
|
* The zeroed flag is used by extent recycling code to track whether
|
|
* memory is zero-filled.
|
|
*/
|
|
bool e_zeroed;
|
|
|
|
/*
|
|
* True if 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.
|
|
*/
|
|
bool e_committed;
|
|
|
|
/*
|
|
* 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().
|
|
*/
|
|
bool e_slab;
|
|
|
|
union {
|
|
/* Small region slab metadata. */
|
|
arena_slab_data_t e_slab_data;
|
|
|
|
/* Profile counters, used for large objects. */
|
|
union {
|
|
void *e_prof_tctx_pun;
|
|
prof_tctx_t *e_prof_tctx;
|
|
};
|
|
};
|
|
|
|
/*
|
|
* 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;
|
|
};
|
|
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 */
|