/******************************************************************************/
#ifdef JEMALLOC_H_TYPES
/*
* RUN_MAX_OVRHD indicates maximum desired run header overhead. Runs are sized
* as small as possible such that this setting is still honored, without
* violating other constraints. The goal is to make runs as small as possible
* without exceeding a per run external fragmentation threshold.
*
* We use binary fixed point math for overhead computations, where the binary
* point is implicitly RUN_BFP bits to the left.
*
* Note that it is possible to set RUN_MAX_OVRHD low enough that it cannot be
* honored for some/all object sizes, since when heap profiling is enabled
* there is one pointer of header overhead per object (plus a constant). This
* constraint is relaxed (ignored) for runs that are so small that the
* per-region overhead is greater than:
*
* (RUN_MAX_OVRHD / (reg_interval << (3+RUN_BFP))
*/
#define RUN_BFP 12
/* \/ Implicit binary fixed point. */
#define RUN_MAX_OVRHD 0x0000003dU
#define RUN_MAX_OVRHD_RELAX 0x00001800U
/* Maximum number of regions in one run. */
#define LG_RUN_MAXREGS 11
#define RUN_MAXREGS (1U << LG_RUN_MAXREGS)
/*
* Minimum redzone size. Redzones may be larger than this if necessary to
* preserve region alignment.
*/
#define REDZONE_MINSIZE 16
/*
* The minimum ratio of active:dirty pages per arena is computed as:
*
* (nactive >> opt_lg_dirty_mult) >= ndirty
*
* So, supposing that opt_lg_dirty_mult is 5, there can be no less than 32
* times as many active pages as dirty pages.
*/
#define LG_DIRTY_MULT_DEFAULT 5
typedef struct arena_chunk_map_s arena_chunk_map_t;
typedef struct arena_chunk_s arena_chunk_t;
typedef struct arena_run_s arena_run_t;
typedef struct arena_bin_info_s arena_bin_info_t;
typedef struct arena_bin_s arena_bin_t;
typedef struct arena_s arena_t;
#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS
/* Each element of the chunk map corresponds to one page within the chunk. */
struct arena_chunk_map_s {
#ifndef JEMALLOC_PROF
/*
* Overlay prof_ctx in order to allow it to be referenced by dead code.
* Such antics aren't warranted for per arena data structures, but
* chunk map overhead accounts for a percentage of memory, rather than
* being just a fixed cost.
*/
union {
#endif
union {
/*
* Linkage for run trees. There are two disjoint uses:
*
* 1) arena_t's runs_avail_{clean,dirty} trees.
* 2) arena_run_t conceptually uses this linkage for in-use
* non-full runs, rather than directly embedding linkage.
*/
rb_node(arena_chunk_map_t) rb_link;
/*
* List of runs currently in purgatory. arena_chunk_purge()
* temporarily allocates runs that contain dirty pages while
* purging, so that other threads cannot use the runs while the
* purging thread is operating without the arena lock held.
*/
ql_elm(arena_chunk_map_t) ql_link;
} u;
/* Profile counters, used for large object runs. */
prof_ctx_t *prof_ctx;
#ifndef JEMALLOC_PROF
}; /* union { ... }; */
#endif
/*
* Run address (or size) and various flags are stored together. The bit
* layout looks like (assuming 32-bit system):
*
* ???????? ???????? ????---- ----dula
*
* ? : Unallocated: Run address for first/last pages, unset for internal
* pages.
* Small: Run page offset.
* Large: Run size for first page, unset for trailing pages.
* - : Unused.
* d : dirty?
* u : unzeroed?
* l : large?
* a : allocated?
*
* Following are example bit patterns for the three types of runs.
*
* p : run page offset
* s : run size
* c : (binind+1) for size class (used only if prof_promote is true)
* x : don't care
* - : 0
* + : 1
* [DULA] : bit set
* [dula] : bit unset
*
* Unallocated (clean):
* ssssssss ssssssss ssss---- ----du-a
* xxxxxxxx xxxxxxxx xxxx---- -----Uxx
* ssssssss ssssssss ssss---- ----dU-a
*
* Unallocated (dirty):
* ssssssss ssssssss ssss---- ----D--a
* xxxxxxxx xxxxxxxx xxxx---- ----xxxx
* ssssssss ssssssss ssss---- ----D--a
*
* Small:
* pppppppp pppppppp pppp---- ----d--A
* pppppppp pppppppp pppp---- -------A
* pppppppp pppppppp pppp---- ----d--A
*
* Large:
* ssssssss ssssssss ssss---- ----D-LA
* xxxxxxxx xxxxxxxx xxxx---- ----xxxx
* -------- -------- -------- ----D-LA
*
* Large (sampled, size <= PAGE):
* ssssssss ssssssss sssscccc ccccD-LA
*
* Large (not sampled, size == PAGE):
* ssssssss ssssssss ssss---- ----D-LA
*/
size_t bits;
#define CHUNK_MAP_CLASS_SHIFT 4
#define CHUNK_MAP_CLASS_MASK ((size_t)0xff0U)
#define CHUNK_MAP_FLAGS_MASK ((size_t)0xfU)
#define CHUNK_MAP_DIRTY ((size_t)0x8U)
#define CHUNK_MAP_UNZEROED ((size_t)0x4U)
#define CHUNK_MAP_LARGE ((size_t)0x2U)
#define CHUNK_MAP_ALLOCATED ((size_t)0x1U)
#define CHUNK_MAP_KEY CHUNK_MAP_ALLOCATED
};
typedef rb_tree(arena_chunk_map_t) arena_avail_tree_t;
typedef rb_tree(arena_chunk_map_t) arena_run_tree_t;
/* Arena chunk header. */
struct arena_chunk_s {
/* Arena that owns the chunk. */
arena_t *arena;
/* Linkage for the arena's chunks_dirty list. */
ql_elm(arena_chunk_t) link_dirty;
/*
* True if the chunk is currently in the chunks_dirty list, due to
* having at some point contained one or more dirty pages. Removal
* from chunks_dirty is lazy, so (dirtied && ndirty == 0) is possible.
*/
bool dirtied;
/* Number of dirty pages. */
size_t ndirty;
/*
* Map of pages within chunk that keeps track of free/large/small. The
* first map_bias entries are omitted, since the chunk header does not
* need to be tracked in the map. This omission saves a header page
* for common chunk sizes (e.g. 4 MiB).
*/
arena_chunk_map_t map[1]; /* Dynamically sized. */
};
typedef rb_tree(arena_chunk_t) arena_chunk_tree_t;
struct arena_run_s {
/* Bin this run is associated with. */
arena_bin_t *bin;
/* Index of next region that has never been allocated, or nregs. */
uint32_t nextind;
/* Number of free regions in run. */
unsigned nfree;
};
/*
* 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 run has the following layout:
*
* /--------------------\
* | arena_run_t header |
* | ... |
* bitmap_offset | bitmap |
* | ... |
* ctx0_offset | ctx map |
* | ... |
* |--------------------|
* | redzone |
* reg0_offset | region 0 |
* | redzone |
* |--------------------| \
* | redzone | |
* | region 1 | > reg_interval
* | redzone | /
* |--------------------|
* | ... |
* | ... |
* | ... |
* |--------------------|
* | redzone |
* | region nregs-1 |
* | redzone |
* |--------------------|
* | alignment pad? |
* \--------------------/
*
* reg_interval has at least the same minimum alignment as reg_size; this
* preserves the alignment constraint that sa2u() depends on. Alignment pad is
* either 0 or redzone_size; it is present only if needed to align reg0_offset.
*/
struct arena_bin_info_s {
/* Size of regions in a run for this bin's size class. */
size_t reg_size;
/* Redzone size. */
size_t redzone_size;
/* Interval between regions (reg_size + (redzone_size << 1)). */
size_t reg_interval;
/* Total size of a run for this bin's size class. */
size_t run_size;
/* Total number of regions in a run for this bin's size class. */
uint32_t nregs;
/*
* Offset of first bitmap_t element in a run header for this bin's size
* class.
*/
uint32_t bitmap_offset;
/*
* Metadata used to manipulate bitmaps for runs associated with this
* bin.
*/
bitmap_info_t bitmap_info;
/*
* Offset of first (prof_ctx_t *) in a run header for this bin's size
* class, or 0 if (config_prof == false || opt_prof == false).
*/
uint32_t ctx0_offset;
/* Offset of first region in a run for this bin's size class. */
uint32_t reg0_offset;
};
struct arena_bin_s {
/*
* All operations on runcur, runs, and stats require that lock be
* locked. Run allocation/deallocation are protected by the arena lock,
* which may be acquired while holding one or more bin locks, but not
* vise versa.
*/
malloc_mutex_t lock;
/*
* Current run being used to service allocations of this bin's size
* class.
*/
arena_run_t *runcur;
/*
* Tree of non-full runs. This tree is used when looking for an
* existing run when runcur is no longer usable. We choose the
* non-full run that is lowest in memory; this policy tends to keep
* objects packed well, and it can also help reduce the number of
* almost-empty chunks.
*/
arena_run_tree_t runs;
/* Bin statistics. */
malloc_bin_stats_t stats;
};
struct arena_s {
/* This arena's index within the arenas array. */
unsigned ind;
/*
* Number of threads currently assigned to this arena. This field is
* protected by arenas_lock.
*/
unsigned nthreads;
/*
* There are three classes of arena operations from a locking
* perspective:
* 1) Thread asssignment (modifies nthreads) is protected by
* arenas_lock.
* 2) Bin-related operations are protected by bin locks.
* 3) Chunk- and run-related operations are protected by this mutex.
*/
malloc_mutex_t lock;
arena_stats_t stats;
/*
* List of tcaches for extant threads associated with this arena.
* Stats from these are merged incrementally, and at exit.
*/
ql_head(tcache_t) tcache_ql;
uint64_t prof_accumbytes;
/* List of dirty-page-containing chunks this arena manages. */
ql_head(arena_chunk_t) chunks_dirty;
/*
* In order to avoid rapid chunk allocation/deallocation when an arena
* oscillates right on the cusp of needing a new chunk, cache the most
* recently freed chunk. The spare is left in the arena's chunk trees
* until it is deleted.
*
* There is one spare chunk per arena, rather than one spare total, in
* order to avoid interactions between multiple threads that could make
* a single spare inadequate.
*/
arena_chunk_t *spare;
/* Number of pages in active runs. */
size_t nactive;
/*
* Current count of pages within unused runs that are potentially
* dirty, and for which madvise(... MADV_DONTNEED) has not been called.
* By tracking this, we can institute a limit on how much dirty unused
* memory is mapped for each arena.
*/
size_t ndirty;
/*
* Approximate number of pages being purged. It is possible for
* multiple threads to purge dirty pages concurrently, and they use
* npurgatory to indicate the total number of pages all threads are
* attempting to purge.
*/
size_t npurgatory;
/*
* Size/address-ordered trees of this arena's available runs. The trees
* are used for first-best-fit run allocation. The dirty tree contains
* runs with dirty pages (i.e. very likely to have been touched and
* therefore have associated physical pages), whereas the clean tree
* contains runs with pages that either have no associated physical
* pages, or have pages that the kernel may recycle at any time due to
* previous madvise(2) calls. The dirty tree is used in preference to
* the clean tree for allocations, because using dirty pages reduces
* the amount of dirty purging necessary to keep the active:dirty page
* ratio below the purge threshold.
*/
arena_avail_tree_t runs_avail_clean;
arena_avail_tree_t runs_avail_dirty;
/* bins is used to store trees of free regions. */
arena_bin_t bins[NBINS];
};
#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS
extern ssize_t opt_lg_dirty_mult;
/*
* small_size2bin is a compact lookup table that rounds request sizes up to
* size classes. In order to reduce cache footprint, the table is compressed,
* and all accesses are via the SMALL_SIZE2BIN macro.
*/
extern uint8_t const small_size2bin[];
#define SMALL_SIZE2BIN(s) (small_size2bin[(s-1) >> LG_TINY_MIN])
extern arena_bin_info_t arena_bin_info[NBINS];
/* Number of large size classes. */
#define nlclasses (chunk_npages - map_bias)
void arena_purge_all(arena_t *arena);
void arena_prof_accum(arena_t *arena, uint64_t accumbytes);
void arena_tcache_fill_small(arena_t *arena, tcache_bin_t *tbin,
size_t binind, uint64_t prof_accumbytes);
void arena_alloc_junk_small(void *ptr, arena_bin_info_t *bin_info,
bool zero);
void arena_dalloc_junk_small(void *ptr, arena_bin_info_t *bin_info);
void *arena_malloc_small(arena_t *arena, size_t size, bool zero);
void *arena_malloc_large(arena_t *arena, size_t size, bool zero);
void *arena_palloc(arena_t *arena, size_t size, size_t alignment, bool zero);
size_t arena_salloc(const void *ptr, bool demote);
void arena_prof_promoted(const void *ptr, size_t size);
void arena_dalloc_bin(arena_t *arena, arena_chunk_t *chunk, void *ptr,
arena_chunk_map_t *mapelm);
void arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk, void *ptr);
void arena_stats_merge(arena_t *arena, size_t *nactive, size_t *ndirty,
arena_stats_t *astats, malloc_bin_stats_t *bstats,
malloc_large_stats_t *lstats);
void *arena_ralloc_no_move(void *ptr, size_t oldsize, size_t size,
size_t extra, bool zero);
void *arena_ralloc(void *ptr, size_t oldsize, size_t size, size_t extra,
size_t alignment, bool zero, bool try_tcache);
bool arena_new(arena_t *arena, unsigned ind);
void arena_boot(void);
void arena_prefork(arena_t *arena);
void arena_postfork_parent(arena_t *arena);
void arena_postfork_child(arena_t *arena);
#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES
#ifndef JEMALLOC_ENABLE_INLINE
size_t arena_bin_index(arena_t *arena, arena_bin_t *bin);
unsigned arena_run_regind(arena_run_t *run, arena_bin_info_t *bin_info,
const void *ptr);
prof_ctx_t *arena_prof_ctx_get(const void *ptr);
void arena_prof_ctx_set(const void *ptr, prof_ctx_t *ctx);
void *arena_malloc(arena_t *arena, size_t size, bool zero, bool try_tcache);
void arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr,
bool try_tcache);
#endif
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_ARENA_C_))
JEMALLOC_INLINE size_t
arena_bin_index(arena_t *arena, arena_bin_t *bin)
{
size_t binind = bin - arena->bins;
assert(binind < NBINS);
return (binind);
}
JEMALLOC_INLINE unsigned
arena_run_regind(arena_run_t *run, arena_bin_info_t *bin_info, const void *ptr)
{
unsigned shift, diff, regind;
size_t interval;
/*
* Freeing a pointer lower than region zero can cause assertion
* failure.
*/
assert((uintptr_t)ptr >= (uintptr_t)run +
(uintptr_t)bin_info->reg0_offset);
/*
* Avoid doing division with a variable divisor if possible. Using
* actual division here can reduce allocator throughput by over 20%!
*/
diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run -
bin_info->reg0_offset);
/* Rescale (factor powers of 2 out of the numerator and denominator). */
interval = bin_info->reg_interval;
shift = ffs(interval) - 1;
diff >>= shift;
interval >>= shift;
if (interval == 1) {
/* The divisor was a power of 2. */
regind = diff;
} else {
/*
* To divide by a number D that is not a power of two we
* multiply by (2^21 / D) and then right shift by 21 positions.
*
* X / D
*
* becomes
*
* (X * interval_invs[D - 3]) >> SIZE_INV_SHIFT
*
* We can omit the first three elements, because we never
* divide by 0, and 1 and 2 are both powers of two, which are
* handled above.
*/
#define SIZE_INV_SHIFT ((sizeof(unsigned) << 3) - LG_RUN_MAXREGS)
#define SIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s)) + 1)
static const unsigned interval_invs[] = {
SIZE_INV(3),
SIZE_INV(4), SIZE_INV(5), SIZE_INV(6), SIZE_INV(7),
SIZE_INV(8), SIZE_INV(9), SIZE_INV(10), SIZE_INV(11),
SIZE_INV(12), SIZE_INV(13), SIZE_INV(14), SIZE_INV(15),
SIZE_INV(16), SIZE_INV(17), SIZE_INV(18), SIZE_INV(19),
SIZE_INV(20), SIZE_INV(21), SIZE_INV(22), SIZE_INV(23),
SIZE_INV(24), SIZE_INV(25), SIZE_INV(26), SIZE_INV(27),
SIZE_INV(28), SIZE_INV(29), SIZE_INV(30), SIZE_INV(31)
};
if (interval <= ((sizeof(interval_invs) / sizeof(unsigned)) +
2)) {
regind = (diff * interval_invs[interval - 3]) >>
SIZE_INV_SHIFT;
} else
regind = diff / interval;
#undef SIZE_INV
#undef SIZE_INV_SHIFT
}
assert(diff == regind * interval);
assert(regind < bin_info->nregs);
return (regind);
}
JEMALLOC_INLINE prof_ctx_t *
arena_prof_ctx_get(const void *ptr)
{
prof_ctx_t *ret;
arena_chunk_t *chunk;
size_t pageind, mapbits;
cassert(config_prof);
assert(ptr != NULL);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> LG_PAGE;
mapbits = chunk->map[pageind-map_bias].bits;
assert((mapbits & CHUNK_MAP_ALLOCATED) != 0);
if ((mapbits & CHUNK_MAP_LARGE) == 0) {
if (prof_promote)
ret = (prof_ctx_t *)(uintptr_t)1U;
else {
arena_run_t *run = (arena_run_t *)((uintptr_t)chunk +
(uintptr_t)((pageind - (mapbits >> LG_PAGE)) <<
LG_PAGE));
size_t binind = arena_bin_index(chunk->arena, run->bin);
arena_bin_info_t *bin_info = &arena_bin_info[binind];
unsigned regind;
regind = arena_run_regind(run, bin_info, ptr);
ret = *(prof_ctx_t **)((uintptr_t)run +
bin_info->ctx0_offset + (regind *
sizeof(prof_ctx_t *)));
}
} else
ret = chunk->map[pageind-map_bias].prof_ctx;
return (ret);
}
JEMALLOC_INLINE void
arena_prof_ctx_set(const void *ptr, prof_ctx_t *ctx)
{
arena_chunk_t *chunk;
size_t pageind, mapbits;
cassert(config_prof);
assert(ptr != NULL);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> LG_PAGE;
mapbits = chunk->map[pageind-map_bias].bits;
assert((mapbits & CHUNK_MAP_ALLOCATED) != 0);
if ((mapbits & CHUNK_MAP_LARGE) == 0) {
if (prof_promote == false) {
arena_run_t *run = (arena_run_t *)((uintptr_t)chunk +
(uintptr_t)((pageind - (mapbits >> LG_PAGE)) <<
LG_PAGE));
arena_bin_t *bin = run->bin;
size_t binind;
arena_bin_info_t *bin_info;
unsigned regind;
binind = arena_bin_index(chunk->arena, bin);
bin_info = &arena_bin_info[binind];
regind = arena_run_regind(run, bin_info, ptr);
*((prof_ctx_t **)((uintptr_t)run + bin_info->ctx0_offset
+ (regind * sizeof(prof_ctx_t *)))) = ctx;
} else
assert((uintptr_t)ctx == (uintptr_t)1U);
} else
chunk->map[pageind-map_bias].prof_ctx = ctx;
}
JEMALLOC_INLINE void *
arena_malloc(arena_t *arena, size_t size, bool zero, bool try_tcache)
{
tcache_t *tcache;
assert(size != 0);
assert(size <= arena_maxclass);
if (size <= SMALL_MAXCLASS) {
if (try_tcache && (tcache = tcache_get(true)) != NULL)
return (tcache_alloc_small(tcache, size, zero));
else {
return (arena_malloc_small(choose_arena(arena), size,
zero));
}
} else {
/*
* Initialize tcache after checking size in order to avoid
* infinite recursion during tcache initialization.
*/
if (try_tcache && size <= tcache_maxclass && (tcache =
tcache_get(true)) != NULL)
return (tcache_alloc_large(tcache, size, zero));
else {
return (arena_malloc_large(choose_arena(arena), size,
zero));
}
}
}
JEMALLOC_INLINE void
arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr, bool try_tcache)
{
size_t pageind;
arena_chunk_map_t *mapelm;
tcache_t *tcache;
assert(arena != NULL);
assert(chunk->arena == arena);
assert(ptr != NULL);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> LG_PAGE;
mapelm = &chunk->map[pageind-map_bias];
assert((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0);
if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
/* Small allocation. */
if (try_tcache && (tcache = tcache_get(false)) != NULL)
tcache_dalloc_small(tcache, ptr);
else {
arena_run_t *run;
arena_bin_t *bin;
run = (arena_run_t *)((uintptr_t)chunk +
(uintptr_t)((pageind - (mapelm->bits >> LG_PAGE)) <<
LG_PAGE));
bin = run->bin;
if (config_debug) {
size_t binind = arena_bin_index(arena, bin);
UNUSED arena_bin_info_t *bin_info =
&arena_bin_info[binind];
assert(((uintptr_t)ptr - ((uintptr_t)run +
(uintptr_t)bin_info->reg0_offset)) %
bin_info->reg_interval == 0);
}
malloc_mutex_lock(&bin->lock);
arena_dalloc_bin(arena, chunk, ptr, mapelm);
malloc_mutex_unlock(&bin->lock);
}
} else {
size_t size = mapelm->bits & ~PAGE_MASK;
assert(((uintptr_t)ptr & PAGE_MASK) == 0);
if (try_tcache && size <= tcache_maxclass && (tcache =
tcache_get(false)) != NULL) {
tcache_dalloc_large(tcache, ptr, size);
} else {
malloc_mutex_lock(&arena->lock);
arena_dalloc_large(arena, chunk, ptr);
malloc_mutex_unlock(&arena->lock);
}
}
}
#endif
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/