/*-
* Copyright (C) 2006 Jason Evans <jasone@FreeBSD.org>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*******************************************************************************
*
* This allocator implementation is designed to provide scalable performance
* for multi-threaded programs on multi-processor systems. The following
* features are included for this purpose:
*
* + Multiple arenas are used if there are multiple CPUs, which reduces lock
* contention and cache sloshing.
*
* + Cache line sharing between arenas is avoided for internal data
* structures.
*
* + Memory is managed in chunks and runs (chunks can be split into runs using
* a binary buddy scheme), rather than as individual pages. This provides
* a constant-time mechanism for associating allocations with particular
* arenas.
*
* Allocation requests are rounded up to the nearest size class, and no record
* of the original request size is maintained. Allocations are broken into
* categories according to size class. Assuming runtime defaults, 4 kB pages
* and a 16 byte quantum, the size classes in each category are as follows:
*
* |====================================|
* | Category | Subcategory | Size |
* |====================================|
* | Small | Tiny | 2 |
* | | | 4 |
* | | | 8 |
* | |----------------+--------|
* | | Quantum-spaced | 16 |
* | | | 32 |
* | | | 48 |
* | | | ... |
* | | | 480 |
* | | | 496 |
* | | | 512 |
* | |----------------+--------|
* | | Sub-page | 1 kB |
* | | | 2 kB |
* |====================================|
* | Large | 4 kB |
* | | 8 kB |
* | | 16 kB |
* | | ... |
* | | 256 kB |
* | | 512 kB |
* | | 1 MB |
* |====================================|
* | Huge | 2 MB |
* | | 4 MB |
* | | 6 MB |
* | | ... |
* |====================================|
*
* A different mechanism is used for each category:
*
* Small : Each size class is segregated into its own set of runs. Each run
* maintains a bitmap of which regions are free/allocated.
*
* Large : Each allocation is backed by a dedicated run. Metadata are stored
* in the associated arena chunk header maps.
*
* Huge : Each allocation is backed by a dedicated contiguous set of chunks.
* Metadata are stored in a separate red-black tree.
*
*******************************************************************************
*/
/*
*******************************************************************************
*
* Ring macros.
*
*******************************************************************************
*/
/* Ring definitions. */
#define qr(a_type) struct { \
a_type *qre_next; \
a_type *qre_prev; \
}
#define qr_initializer {NULL, NULL}
/* Ring functions. */
#define qr_new(a_qr, a_field) do { \
(a_qr)->a_field.qre_next = (a_qr); \
(a_qr)->a_field.qre_prev = (a_qr); \
} while (0)
#define qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next)
#define qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev)
#define qr_before_insert(a_qrelm, a_qr, a_field) do { \
(a_qr)->a_field.qre_prev = (a_qrelm)->a_field.qre_prev; \
(a_qr)->a_field.qre_next = (a_qrelm); \
(a_qr)->a_field.qre_prev->a_field.qre_next = (a_qr); \
(a_qrelm)->a_field.qre_prev = (a_qr); \
} while (0)
#define qr_after_insert(a_qrelm, a_qr, a_field) do { \
(a_qr)->a_field.qre_next = (a_qrelm)->a_field.qre_next; \
(a_qr)->a_field.qre_prev = (a_qrelm); \
(a_qr)->a_field.qre_next->a_field.qre_prev = (a_qr); \
(a_qrelm)->a_field.qre_next = (a_qr); \
} while (0)
#define qr_meld(a_qr_a, a_qr_b, a_type, a_field) do { \
a_type *t; \
(a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_b); \
(a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_a); \
t = (a_qr_a)->a_field.qre_prev; \
(a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev; \
(a_qr_b)->a_field.qre_prev = t; \
} while (0)
/*
* qr_meld() and qr_split() are functionally equivalent, so there's no need to
* have two copies of the code.
*/
#define qr_split(a_qr_a, a_qr_b, a_type, a_field) \
qr_meld((a_qr_a), (a_qr_b), a_type, a_field)
#define qr_remove(a_qr, a_field) do { \
(a_qr)->a_field.qre_prev->a_field.qre_next \
= (a_qr)->a_field.qre_next; \
(a_qr)->a_field.qre_next->a_field.qre_prev \
= (a_qr)->a_field.qre_prev; \
(a_qr)->a_field.qre_next = (a_qr); \
(a_qr)->a_field.qre_prev = (a_qr); \
} while (0)
#define qr_foreach(var, a_qr, a_field) \
for ((var) = (a_qr); \
(var) != NULL; \
(var) = (((var)->a_field.qre_next != (a_qr)) \
? (var)->a_field.qre_next : NULL))
#define qr_reverse_foreach(var, a_qr, a_field) \
for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL; \
(var) != NULL; \
(var) = (((var) != (a_qr)) \
? (var)->a_field.qre_prev : NULL))
/******************************************************************************/
/*
* In order to disable various extra features that may have negative
* performance impacts, (assertions, expanded statistics), define
* NO_MALLOC_EXTRAS.
*/
/* #define NO_MALLOC_EXTRAS */
#ifndef NO_MALLOC_EXTRAS
# define MALLOC_DEBUG
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "libc_private.h"
#ifdef MALLOC_DEBUG
# define _LOCK_DEBUG
#endif
#include "spinlock.h"
#include "namespace.h"
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/stddef.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <sys/tree.h>
#include <sys/uio.h>
#include <sys/ktrace.h> /* Must come after several other sys/ includes. */
#include <machine/atomic.h>
#include <machine/cpufunc.h>
#include <machine/vmparam.h>
#include <errno.h>
#include <limits.h>
#include <pthread.h>
#include <sched.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include "un-namespace.h"
/*
* Calculate statistics that can be used to get an idea of how well caching is
* working.
*/
#ifndef NO_MALLOC_EXTRAS
# define MALLOC_STATS
#endif
#ifndef MALLOC_DEBUG
# ifndef NDEBUG
# define NDEBUG
# endif
#endif
#include <assert.h>
#ifdef MALLOC_DEBUG
/* Disable inlining to make debugging easier. */
# define inline
#endif
/* Size of stack-allocated buffer passed to strerror_r(). */
#define STRERROR_BUF 64
/* Minimum alignment of allocations is 2^QUANTUM_2POW_MIN bytes. */
#ifdef __i386__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR 4
# define USE_BRK
#endif
#ifdef __ia64__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR 8
# define NO_TLS
#endif
#ifdef __alpha__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR 8
# define NO_TLS
#endif
#ifdef __sparc64__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR 8
# define NO_TLS
#endif
#ifdef __amd64__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR 8
#endif
#ifdef __arm__
# define QUANTUM_2POW_MIN 3
# define SIZEOF_PTR 4
# define USE_BRK
# define NO_TLS
#endif
#ifdef __powerpc__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR 4
# define USE_BRK
#endif
/* sizeof(int) == (1 << SIZEOF_INT_2POW). */
#ifndef SIZEOF_INT_2POW
# define SIZEOF_INT_2POW 2
#endif
/* We can't use TLS in non-PIC programs, since TLS relies on loader magic. */
#if (!defined(PIC) && !defined(NO_TLS))
# define NO_TLS
#endif
/*
* Size and alignment of memory chunks that are allocated by the OS's virtual
* memory system.
*
* chunksize limits:
*
* 2^(pagesize_2pow - 1 + RUN_MIN_REGS_2POW) <= chunk_size <= 2^28
*/
#define CHUNK_2POW_DEFAULT 21
#define CHUNK_2POW_MAX 28
/*
* Maximum size of L1 cache line. This is used to avoid cache line aliasing,
* so over-estimates are okay (up to a point), but under-estimates will
* negatively affect performance.
*/
#define CACHELINE_2POW 6
#define CACHELINE ((size_t)(1 << CACHELINE_2POW))
/*
* Maximum size class that is a multiple of the quantum, but not (necessarily)
* a power of 2. Above this size, allocations are rounded up to the nearest
* power of 2.
*/
#define SMALL_MAX_2POW_DEFAULT 9
#define SMALL_MAX_DEFAULT (1 << SMALL_MAX_2POW_DEFAULT)
/*
* Minimum number of regions that must fit into a run that serves quantum-size
* bin allocations.
*
* Note that if this is set too low, space will be wasted if there are size
* classes that are small enough that RUN_MIN_REGS regions don't fill a page.
* If this is set too high, then the overhead of searching through the bitmap
* that tracks region usage will become excessive.
*/
#define RUN_MIN_REGS_2POW 10
#define RUN_MIN_REGS (1 << RUN_MIN_REGS_2POW)
/*
* Maximum number of pages for a run that is used for bin allocations.
*
* Note that if this is set too low, then fragmentation for the largest bin
* size classes will be high. If this is set too high, then even small
* programs will often have to allocate more than two chunks early on.
*/
#define RUN_MAX_PAGES_2POW 4
#define RUN_MAX_PAGES (1 << RUN_MAX_PAGES_2POW)
/******************************************************************************/
/*
* Mutexes based on spinlocks. We can't use normal pthread mutexes, because
* they require malloc()ed memory.
*/
typedef struct {
spinlock_t lock;
} malloc_mutex_t;
/* Set to true once the allocator has been initialized. */
static bool malloc_initialized = false;
/* Used to avoid initialization races. */
static malloc_mutex_t init_lock = {_SPINLOCK_INITIALIZER};
/******************************************************************************/
/*
* Statistics data structures.
*/
#ifdef MALLOC_STATS
typedef struct malloc_bin_stats_s malloc_bin_stats_t;
struct malloc_bin_stats_s {
/*
* Number of allocation requests that corresponded to the size of this
* bin.
*/
uint64_t nrequests;
/* Total number of runs created for this bin's size class. */
uint64_t nruns;
/*
* Total number of run promotions/demotions for this bin's size class.
*/
uint64_t npromote;
uint64_t ndemote;
/* High-water mark for this bin. */
unsigned long highruns;
/* Current number of runs in this bin. */
unsigned long curruns;
};
typedef struct arena_stats_s arena_stats_t;
struct arena_stats_s {
/* Total byte count of allocated memory, not including overhead. */
size_t allocated;
/* Number of times each function was called. */
uint64_t nmalloc;
uint64_t ndalloc;
uint64_t nmadvise;
/* Number of large allocation requests. */
uint64_t large_nrequests;
};
typedef struct chunk_stats_s chunk_stats_t;
struct chunk_stats_s {
/* Number of chunks that were allocated. */
uint64_t nchunks;
/* High-water mark for number of chunks allocated. */
unsigned long highchunks;
/*
* Current number of chunks allocated. This value isn't maintained for
* any other purpose, so keep track of it in order to be able to set
* highchunks.
*/
unsigned long curchunks;
};
#endif /* #ifdef MALLOC_STATS */
/******************************************************************************/
/*
* Chunk data structures.
*/
/* Tree of chunks. */
typedef struct chunk_node_s chunk_node_t;
struct chunk_node_s {
/* Linkage for the chunk tree. */
RB_ENTRY(chunk_node_s) link;
/*
* Pointer to the chunk that this tree node is responsible for. In some
* (but certainly not all) cases, this data structure is placed at the
* beginning of the corresponding chunk, so this field may point to this
* node.
*/
void *chunk;
/* Total chunk size. */
size_t size;
};
typedef struct chunk_tree_s chunk_tree_t;
RB_HEAD(chunk_tree_s, chunk_node_s);
/******************************************************************************/
/*
* Arena data structures.
*/
typedef struct arena_s arena_t;
typedef struct arena_bin_s arena_bin_t;
typedef struct arena_chunk_map_s arena_chunk_map_t;
struct arena_chunk_map_s {
bool free:1;
bool large:1;
unsigned npages:15; /* Limiting factor for CHUNK_2POW_MAX. */
unsigned pos:15;
};
/* Arena chunk header. */
typedef struct arena_chunk_s arena_chunk_t;
struct arena_chunk_s {
/* Arena that owns the chunk. */
arena_t *arena;
/* Linkage for the arena's chunk tree. */
RB_ENTRY(arena_chunk_s) link;
/*
* Number of pages in use. This is maintained in order to make
* detection of empty chunks fast.
*/
uint32_t pages_used;
/*
* Array of counters that keeps track of how many free runs of each
* size are available in this chunk. This table is sized at compile
* time, which is wasteful. However, due to unrelated rounding, this
* doesn't actually waste any otherwise useful space.
*
* index == 2^n pages
*
* index | npages
* ------+-------
* 0 | 1
* 1 | 2
* 2 | 4
* 3 | 8
* :
*/
uint32_t nfree_runs[CHUNK_2POW_MAX/* - PAGE_SHIFT */];
/* Map of pages within chunk that keeps track of free/large/small. */
arena_chunk_map_t map[1]; /* Dynamically sized. */
};
typedef struct arena_chunk_tree_s arena_chunk_tree_t;
RB_HEAD(arena_chunk_tree_s, arena_chunk_s);
typedef struct arena_run_s arena_run_t;
struct arena_run_s {
/* Linkage for run rings. */
qr(arena_run_t) link;
#ifdef MALLOC_DEBUG
uint32_t magic;
# define ARENA_RUN_MAGIC 0x384adf93
#endif
/* Bin this run is associated with. */
arena_bin_t *bin;
/* Bitmask of in-use regions (0: in use, 1: free). */
#define REGS_MASK_NELMS \
(1 << (RUN_MIN_REGS_2POW - SIZEOF_INT_2POW - 2))
unsigned regs_mask[REGS_MASK_NELMS];
/* Index of first element that might have a free region. */
unsigned regs_minelm;
/* Number of free regions in run. */
unsigned nfree:(RUN_MIN_REGS_2POW + 2);
/*
* Current quartile for this run, one of: {RUN_QINIT, RUN_Q0, RUN_25,
* RUN_Q50, RUN_Q75, RUN_Q100}.
*/
#define RUN_QINIT 0
#define RUN_Q0 1
#define RUN_Q25 2
#define RUN_Q50 3
#define RUN_Q75 4
#define RUN_Q100 5
unsigned quartile;
/*
* Limits on the number of free regions for the fullness quartile this
* run is currently in. If nfree goes outside these limits, the run
* is moved to a different fullness quartile.
*/
unsigned free_max;
unsigned free_min;
};
/* Used for run ring headers, where the run isn't actually used. */
typedef struct arena_run_link_s arena_run_link_t;
struct arena_run_link_s {
/* Linkage for run rings. */
qr(arena_run_t) link;
};
struct arena_bin_s {
/*
* Current run being used to service allocations of this bin's size
* class.
*/
arena_run_t *runcur;
/*
* Links into rings of runs, of various fullnesses (names indicate
* approximate lower bounds). A new run conceptually starts off in
* runsinit, and it isn't inserted into the runs0 ring until it
* reaches 25% full (hysteresis mechanism). For the run to be moved
* again, it must become either empty or 50% full. Thus, each ring
* contains runs that are within 50% above the advertised fullness for
* the ring. This provides a low-overhead mechanism for segregating
* runs into approximate fullness classes.
*
* Conceptually, there is a runs100 that contains completely full runs.
* Since we don't need to search for these runs though, no runs100 ring
* is actually maintained.
*
* These rings are useful when looking for an existing run to use when
* runcur is no longer usable. We look for usable runs in the
* following order:
*
* 1) runs50
* 2) runs25
* 3) runs0
* 4) runs75
*
* runs75 isn't a good place to look, because it contains runs that may
* be nearly completely full. Still, we look there as a last resort in
* order to avoid allocating a new run if at all possible.
*/
/* arena_run_link_t runsinit; 0% <= fullness < 25% */
arena_run_link_t runs0; /* 0% < fullness < 50% */
arena_run_link_t runs25; /* 25% < fullness < 75% */
arena_run_link_t runs50; /* 50% < fullness < 100% */
arena_run_link_t runs75; /* 75% < fullness < 100% */
/* arena_run_link_t runs100; fullness == 100% */
/* Size of regions in a run for this bin's size class. */
size_t reg_size;
/* 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 region in a run for this bin's size class. */
uint32_t reg0_offset;
#ifdef MALLOC_STATS
/* Bin statistics. */
malloc_bin_stats_t stats;
#endif
};
struct arena_s {
#ifdef MALLOC_DEBUG
uint32_t magic;
# define ARENA_MAGIC 0x947d3d24
#endif
/* All operations on this arena require that mtx be locked. */
malloc_mutex_t mtx;
#ifdef MALLOC_STATS
arena_stats_t stats;
#endif
/*
* Tree of chunks this arena manages.
*/
arena_chunk_tree_t chunks;
/*
* bins is used to store rings of free regions of the following sizes,
* assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS.
*
* bins[i] | size |
* --------+------+
* 0 | 2 |
* 1 | 4 |
* 2 | 8 |
* --------+------+
* 3 | 16 |
* 4 | 32 |
* 5 | 48 |
* 6 | 64 |
* : :
* : :
* 33 | 496 |
* 34 | 512 |
* --------+------+
* 35 | 1024 |
* 36 | 2048 |
* --------+------+
*/
arena_bin_t bins[1]; /* Dynamically sized. */
};
/******************************************************************************/
/*
* Data.
*/
/* Used as a special "nil" return value for malloc(0). */
static const int nil;
/* Number of CPUs. */
static unsigned ncpus;
/* VM page size. */
static unsigned pagesize;
static unsigned pagesize_2pow;
/* Various bin-related settings. */
static size_t bin_maxclass; /* Max size class for bins. */
static unsigned ntbins; /* Number of (2^n)-spaced tiny bins. */
static unsigned nqbins; /* Number of quantum-spaced bins. */
static unsigned nsbins; /* Number of (2^n)-spaced sub-page bins. */
static size_t small_min;
static size_t small_max;
static unsigned tiny_min_2pow;
/* Various quantum-related settings. */
static size_t quantum;
static size_t quantum_mask; /* (quantum - 1). */
/* Various chunk-related settings. */
static size_t chunk_size;
static size_t chunk_size_mask; /* (chunk_size - 1). */
static size_t arena_maxclass; /* Max size class for arenas. */
static unsigned arena_chunk_maplen;
/********/
/*
* Chunks.
*/
/* Protects chunk-related data structures. */
static malloc_mutex_t chunks_mtx;
/* Tree of chunks that are stand-alone huge allocations. */
static chunk_tree_t huge;
#ifdef USE_BRK
/*
* Try to use brk for chunk-size allocations, due to address space constraints.
*/
/* Result of first sbrk(0) call. */
static void *brk_base;
/* Current end of brk, or ((void *)-1) if brk is exhausted. */
static void *brk_prev;
/* Current upper limit on brk addresses. */
static void *brk_max;
#endif
#ifdef MALLOC_STATS
/*
* Byte counters for allocated/total space used by the chunks in the huge
* allocations tree.
*/
static uint64_t huge_nmalloc;
static uint64_t huge_ndalloc;
static size_t huge_allocated;
#endif
/*
* Tree of chunks that were previously allocated. This is used when allocating
* chunks, in an attempt to re-use address space.
*/
static chunk_tree_t old_chunks;
/****************************/
/*
* base (internal allocation).
*/
/*
* Current chunk that is being used for internal memory allocations. This
* chunk is carved up in cacheline-size quanta, so that there is no chance of
* false cache line sharing.
*/
static void *base_chunk;
static void *base_next_addr;
static void *base_past_addr; /* Addr immediately past base_chunk. */
static chunk_node_t *base_chunk_nodes; /* LIFO cache of chunk nodes. */
static malloc_mutex_t base_mtx;
#ifdef MALLOC_STATS
static uint64_t base_total;
#endif
/********/
/*
* Arenas.
*/
/*
* Arenas that are used to service external requests. Not all elements of the
* arenas array are necessarily used; arenas are created lazily as needed.
*/
static arena_t **arenas;
static unsigned narenas;
#ifndef NO_TLS
static unsigned next_arena;
#endif
static malloc_mutex_t arenas_mtx; /* Protects arenas initialization. */
#ifndef NO_TLS
/*
* Map of pthread_self() --> arenas[???], used for selecting an arena to use
* for allocations.
*/
static __thread arena_t *arenas_map;
#endif
#ifdef MALLOC_STATS
/* Chunk statistics. */
static chunk_stats_t stats_chunks;
#endif
/*******************************/
/*
* Runtime configuration options.
*/
const char *_malloc_options;
#ifndef NO_MALLOC_EXTRAS
static bool opt_abort = true;
static bool opt_junk = true;
#else
static bool opt_abort = false;
static bool opt_junk = false;
#endif
static bool opt_hint = false;
static bool opt_print_stats = false;
static size_t opt_quantum_2pow = QUANTUM_2POW_MIN;
static size_t opt_small_max_2pow = SMALL_MAX_2POW_DEFAULT;
static size_t opt_chunk_2pow = CHUNK_2POW_DEFAULT;
static bool opt_utrace = false;
static bool opt_sysv = false;
static bool opt_xmalloc = false;
static bool opt_zero = false;
static int32_t opt_narenas_lshift = 0;
typedef struct {
void *p;
size_t s;
void *r;
} malloc_utrace_t;
#define UTRACE(a, b, c) \
if (opt_utrace) { \
malloc_utrace_t ut = {a, b, c}; \
utrace(&ut, sizeof(ut)); \
}
/******************************************************************************/
/*
* Begin function prototypes for non-inline static functions.
*/
static void malloc_mutex_init(malloc_mutex_t *a_mutex);
static void wrtmessage(const char *p1, const char *p2, const char *p3,
const char *p4);
static void malloc_printf(const char *format, ...);
static void *base_alloc(size_t size);
static chunk_node_t *base_chunk_node_alloc(void);
static void base_chunk_node_dealloc(chunk_node_t *node);
#ifdef MALLOC_STATS
static void stats_print(arena_t *arena);
#endif
static void *pages_map(void *addr, size_t size);
static void pages_unmap(void *addr, size_t size);
static void *chunk_alloc(size_t size);
static void chunk_dealloc(void *chunk, size_t size);
#ifndef NO_TLS
static arena_t *choose_arena_hard(void);
#endif
static void arena_run_split(arena_t *arena, arena_run_t *run, bool large,
size_t size);
static arena_chunk_t *arena_chunk_alloc(arena_t *arena);
static void arena_chunk_dealloc(arena_chunk_t *chunk);
static void arena_bin_run_promote(arena_t *arena, arena_bin_t *bin,
arena_run_t *run, size_t size);
static void arena_bin_run_demote(arena_t *arena, arena_bin_t *bin,
arena_run_t *run, size_t size);
static arena_run_t *arena_run_alloc(arena_t *arena, bool large, size_t size);
static void arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size);
static arena_run_t *arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin,
size_t size);
static void *arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin,
size_t size);
static void *arena_malloc(arena_t *arena, size_t size);
static size_t arena_salloc(const void *ptr);
static void *arena_ralloc(void *ptr, size_t size, size_t oldsize);
static void arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr);
static bool arena_new(arena_t *arena);
static arena_t *arenas_extend(unsigned ind);
static void *huge_malloc(size_t size);
static void *huge_ralloc(void *ptr, size_t size, size_t oldsize);
static void huge_dalloc(void *ptr);
static void *imalloc(size_t size);
static void *ipalloc(size_t alignment, size_t size);
static void *icalloc(size_t size);
static size_t isalloc(const void *ptr);
static void *iralloc(void *ptr, size_t size);
static void idalloc(void *ptr);
static void malloc_print_stats(void);
static bool malloc_init_hard(void);
/*
* End function prototypes.
*/
/******************************************************************************/
/*
* Begin mutex.
*/
static void
malloc_mutex_init(malloc_mutex_t *a_mutex)
{
static const spinlock_t lock = _SPINLOCK_INITIALIZER;
a_mutex->lock = lock;
}
static inline void
malloc_mutex_lock(malloc_mutex_t *a_mutex)
{
if (__isthreaded)
_SPINLOCK(&a_mutex->lock);
}
static inline void
malloc_mutex_unlock(malloc_mutex_t *a_mutex)
{
if (__isthreaded)
_SPINUNLOCK(&a_mutex->lock);
}
/*
* End mutex.
*/
/******************************************************************************/
/*
* Begin Utility functions/macros.
*/
/* Return the chunk address for allocation address a. */
#define CHUNK_ADDR2BASE(a) \
((void *)((uintptr_t)(a) & ~chunk_size_mask))
/* Return the chunk offset of address a. */
#define CHUNK_ADDR2OFFSET(a) \
((size_t)((uintptr_t)(a) & chunk_size_mask))
/* Return the smallest chunk multiple that is >= s. */
#define CHUNK_CEILING(s) \
(((s) + chunk_size_mask) & ~chunk_size_mask)
/* Return the smallest cacheline multiple that is >= s. */
#define CACHELINE_CEILING(s) \
(((s) + (CACHELINE - 1)) & ~(CACHELINE - 1))
/* Return the smallest quantum multiple that is >= a. */
#define QUANTUM_CEILING(a) \
(((a) + quantum_mask) & ~quantum_mask)
/* Compute the smallest power of 2 that is >= x. */
static inline size_t
pow2_ceil(size_t x)
{
x--;
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
#if (SIZEOF_PTR == 8)
x |= x >> 32;
#endif
x++;
return (x);
}
static void
wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4)
{
_write(STDERR_FILENO, p1, strlen(p1));
_write(STDERR_FILENO, p2, strlen(p2));
_write(STDERR_FILENO, p3, strlen(p3));
_write(STDERR_FILENO, p4, strlen(p4));
}
void (*_malloc_message)(const char *p1, const char *p2, const char *p3,
const char *p4) = wrtmessage;
/*
* Print to stderr in such a way as to (hopefully) avoid memory allocation.
*/
static void
malloc_printf(const char *format, ...)
{
char buf[4096];
va_list ap;
va_start(ap, format);
vsnprintf(buf, sizeof(buf), format, ap);
va_end(ap);
_malloc_message(buf, "", "", "");
}
/******************************************************************************/
static void *
base_alloc(size_t size)
{
void *ret;
size_t csize;
/* Round size up to nearest multiple of the cacheline size. */
csize = CACHELINE_CEILING(size);
malloc_mutex_lock(&base_mtx);
/* Make sure there's enough space for the allocation. */
if ((uintptr_t)base_next_addr + csize > (uintptr_t)base_past_addr) {
void *tchunk;
assert(csize <= chunk_size);
tchunk = chunk_alloc(chunk_size);
if (tchunk == NULL) {
ret = NULL;
goto RETURN;
}
base_chunk = tchunk;
base_next_addr = (void *)base_chunk;
base_past_addr = (void *)((uintptr_t)base_chunk + chunk_size);
#ifdef MALLOC_STATS
base_total += chunk_size;
#endif
}
/* Allocate. */
ret = base_next_addr;
base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
RETURN:
malloc_mutex_unlock(&base_mtx);
return (ret);
}
static chunk_node_t *
base_chunk_node_alloc(void)
{
chunk_node_t *ret;
malloc_mutex_lock(&base_mtx);
if (base_chunk_nodes != NULL) {
ret = base_chunk_nodes;
base_chunk_nodes = *(chunk_node_t **)ret;
malloc_mutex_unlock(&base_mtx);
} else {
malloc_mutex_unlock(&base_mtx);
ret = (chunk_node_t *)base_alloc(sizeof(chunk_node_t));
}
return (ret);
}
static void
base_chunk_node_dealloc(chunk_node_t *node)
{
malloc_mutex_lock(&base_mtx);
*(chunk_node_t **)node = base_chunk_nodes;
base_chunk_nodes = node;
malloc_mutex_unlock(&base_mtx);
}
/******************************************************************************/
#ifdef MALLOC_STATS
static void
stats_print(arena_t *arena)
{
unsigned i;
int gap_start;
malloc_printf("allocated: %zu\n", arena->stats.allocated);
malloc_printf("calls:\n");
malloc_printf(" %12s %12s %12s\n", "nmalloc","ndalloc", "nmadvise");
malloc_printf(" %12llu %12llu %12llu\n",
arena->stats.nmalloc, arena->stats.ndalloc, arena->stats.nmadvise);
malloc_printf("large requests: %llu\n", arena->stats.large_nrequests);
malloc_printf("bins:\n");
malloc_printf("%13s %1s %4s %5s %6s %9s %5s %6s %7s %6s %6s\n",
"bin", "", "size", "nregs", "run_sz", "nrequests", "nruns",
"hiruns", "curruns", "npromo", "ndemo");
for (i = 0, gap_start = -1; i < ntbins + nqbins + nsbins; i++) {
if (arena->bins[i].stats.nrequests == 0) {
if (gap_start == -1)
gap_start = i;
} else {
if (gap_start != -1) {
if (i > gap_start + 1) {
/* Gap of more than one size class. */
malloc_printf("[%u..%u]\n",
gap_start, i - 1);
} else {
/* Gap of one size class. */
malloc_printf("[%u]\n", gap_start);
}
gap_start = -1;
}
malloc_printf(
"%13u %1s %4u %5u %6u %9llu %5llu"
" %6lu %7lu %6llu %6llu\n",
i,
i < ntbins ? "T" : i < ntbins + nqbins ? "Q" : "S",
arena->bins[i].reg_size,
arena->bins[i].nregs,
arena->bins[i].run_size,
arena->bins[i].stats.nrequests,
arena->bins[i].stats.nruns,
arena->bins[i].stats.highruns,
arena->bins[i].stats.curruns,
arena->bins[i].stats.npromote,
arena->bins[i].stats.ndemote);
}
}
if (gap_start != -1) {
if (i > gap_start + 1) {
/* Gap of more than one size class. */
malloc_printf("[%u..%u]\n", gap_start, i - 1);
} else {
/* Gap of one size class. */
malloc_printf("[%u]\n", gap_start);
}
}
}
#endif
/*
* End Utility functions/macros.
*/
/******************************************************************************/
/*
* Begin chunk management functions.
*/
static inline int
chunk_comp(chunk_node_t *a, chunk_node_t *b)
{
assert(a != NULL);
assert(b != NULL);
if ((uintptr_t)a->chunk < (uintptr_t)b->chunk)
return (-1);
else if (a->chunk == b->chunk)
return (0);
else
return (1);
}
/* Generate red-black tree code for chunks. */
RB_GENERATE_STATIC(chunk_tree_s, chunk_node_s, link, chunk_comp);
static void *
pages_map(void *addr, size_t size)
{
void *ret;
/*
* We don't use MAP_FIXED here, because it can cause the *replacement*
* of existing mappings, and we only want to create new mappings.
*/
ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
-1, 0);
assert(ret != NULL);
if (ret == MAP_FAILED)
ret = NULL;
else if (addr != NULL && ret != addr) {
/*
* We succeeded in mapping memory, but not in the right place.
*/
if (munmap(ret, size) == -1) {
char buf[STRERROR_BUF];
strerror_r(errno, buf, sizeof(buf));
malloc_printf("%s: (malloc) Error in munmap(): %s\n",
_getprogname(), buf);
if (opt_abort)
abort();
}
ret = NULL;
}
assert(ret == NULL || (addr == NULL && ret != addr)
|| (addr != NULL && ret == addr));
return (ret);
}
static void
pages_unmap(void *addr, size_t size)
{
if (munmap(addr, size) == -1) {
char buf[STRERROR_BUF];
strerror_r(errno, buf, sizeof(buf));
malloc_printf("%s: (malloc) Error in munmap(): %s\n",
_getprogname(), buf);
if (opt_abort)
abort();
}
}
static void *
chunk_alloc(size_t size)
{
void *ret, *chunk;
chunk_node_t *tchunk, *delchunk;
assert(size != 0);
assert(size % chunk_size == 0);
malloc_mutex_lock(&chunks_mtx);
if (size == chunk_size) {
/*
* Check for address ranges that were previously chunks and try
* to use them.
*/
tchunk = RB_MIN(chunk_tree_s, &old_chunks);
while (tchunk != NULL) {
/* Found an address range. Try to recycle it. */
chunk = tchunk->chunk;
delchunk = tchunk;
tchunk = RB_NEXT(chunk_tree_s, &old_chunks, delchunk);
/* Remove delchunk from the tree. */
RB_REMOVE(chunk_tree_s, &old_chunks, delchunk);
base_chunk_node_dealloc(delchunk);
#ifdef USE_BRK
if ((uintptr_t)chunk >= (uintptr_t)brk_base
&& (uintptr_t)chunk < (uintptr_t)brk_max) {
/* Re-use a previously freed brk chunk. */
ret = chunk;
goto RETURN;
}
#endif
if ((ret = pages_map(chunk, size)) != NULL) {
/* Success. */
goto RETURN;
}
}
}
#ifdef USE_BRK
/*
* Try to create allocations in brk, in order to make full use of
* limited address space.
*/
if (brk_prev != (void *)-1) {
void *brk_cur;
intptr_t incr;
/*
* The loop is necessary to recover from races with other
* threads that are using brk for something other than malloc.
*/
do {
/* Get the current end of brk. */
brk_cur = sbrk(0);
/*
* Calculate how much padding is necessary to
* chunk-align the end of brk.
*/
incr = (intptr_t)size
- (intptr_t)CHUNK_ADDR2OFFSET(brk_cur);
if (incr == size) {
ret = brk_cur;
} else {
ret = (void *)(intptr_t)brk_cur + incr;
incr += size;
}
brk_prev = sbrk(incr);
if (brk_prev == brk_cur) {
/* Success. */
brk_max = (void *)(intptr_t)ret + size;
goto RETURN;
}
} while (brk_prev != (void *)-1);
}
#endif
/*
* Try to over-allocate, but allow the OS to place the allocation
* anywhere. Beware of size_t wrap-around.
*/
if (size + chunk_size > size) {
if ((ret = pages_map(NULL, size + chunk_size)) != NULL) {
size_t offset = CHUNK_ADDR2OFFSET(ret);
/*
* Success. Clean up unneeded leading/trailing space.
*/
if (offset != 0) {
/* Leading space. */
pages_unmap(ret, chunk_size - offset);
ret = (void *)((uintptr_t)ret + (chunk_size -
offset));
/* Trailing space. */
pages_unmap((void *)((uintptr_t)ret + size),
offset);
} else {
/* Trailing space only. */
pages_unmap((void *)((uintptr_t)ret + size),
chunk_size);
}
goto RETURN;
}
}
/* All strategies for allocation failed. */
ret = NULL;
RETURN:
#ifdef MALLOC_STATS
if (ret != NULL) {
stats_chunks.nchunks += (size / chunk_size);
stats_chunks.curchunks += (size / chunk_size);
}
if (stats_chunks.curchunks > stats_chunks.highchunks)
stats_chunks.highchunks = stats_chunks.curchunks;
#endif
malloc_mutex_unlock(&chunks_mtx);
assert(CHUNK_ADDR2BASE(ret) == ret);
return (ret);
}
static void
chunk_dealloc(void *chunk, size_t size)
{
size_t offset;
chunk_node_t *node;
assert(chunk != NULL);
assert(CHUNK_ADDR2BASE(chunk) == chunk);
assert(size != 0);
assert(size % chunk_size == 0);
malloc_mutex_lock(&chunks_mtx);
#ifdef USE_BRK
if ((uintptr_t)chunk >= (uintptr_t)brk_base
&& (uintptr_t)chunk < (uintptr_t)brk_max) {
void *brk_cur;
/* Get the current end of brk. */
brk_cur = sbrk(0);
/*
* Try to shrink the data segment if this chunk is at the end
* of the data segment. The sbrk() call here is subject to a
* race condition with threads that use brk(2) or sbrk(2)
* directly, but the alternative would be to leak memory for
* the sake of poorly designed multi-threaded programs.
*/
if (brk_cur == brk_max
&& (void *)(uintptr_t)chunk + size == brk_max
&& sbrk(-(intptr_t)size) == brk_max) {
if (brk_prev == brk_max) {
/* Success. */
brk_prev = (void *)(intptr_t)brk_max
- (intptr_t)size;
brk_max = brk_prev;
}
goto RETURN;
} else
madvise(chunk, size, MADV_FREE);
} else
#endif
pages_unmap(chunk, size);
/*
* Iteratively create records of each chunk-sized memory region that
* 'chunk' is comprised of, so that the address range can be recycled
* if memory usage increases later on.
*/
for (offset = 0; offset < size; offset += chunk_size) {
node = base_chunk_node_alloc();
if (node == NULL)
break;
node->chunk = (void *)((uintptr_t)chunk + (uintptr_t)offset);
node->size = chunk_size;
RB_INSERT(chunk_tree_s, &old_chunks, node);
}
#ifdef USE_BRK
RETURN:
#endif
#ifdef MALLOC_STATS
stats_chunks.curchunks -= (size / chunk_size);
#endif
malloc_mutex_unlock(&chunks_mtx);
}
/*
* End chunk management functions.
*/
/******************************************************************************/
/*
* Begin arena.
*/
/*
* Choose an arena based on a per-thread value (fast-path code, calls slow-path
* code if necessary.
*/
static inline arena_t *
choose_arena(void)
{
arena_t *ret;
/*
* We can only use TLS if this is a PIC library, since for the static
* library version, libc's malloc is used by TLS allocation, which
* introduces a bootstrapping issue.
*/
#ifndef NO_TLS
if (__isthreaded == false) {
/*
* Avoid the overhead of TLS for single-threaded operation. If the
* app switches to threaded mode, the initial thread may end up
* being assigned to some other arena, but this one-time switch
* shouldn't cause significant issues.
* */
return (arenas[0]);
}
ret = arenas_map;
if (ret == NULL)
ret = choose_arena_hard();
#else
if (__isthreaded) {
unsigned long ind;
/*
* Hash _pthread_self() to one of the arenas. There is a prime
* number of arenas, so this has a reasonable chance of
* working. Even so, the hashing can be easily thwarted by
* inconvenient _pthread_self() values. Without specific
* knowledge of how _pthread_self() calculates values, we can't
* easily do much better than this.
*/
ind = (unsigned long) _pthread_self() % narenas;
/*
* Optimistially assume that arenas[ind] has been initialized.
* At worst, we find out that some other thread has already
* done so, after acquiring the lock in preparation. Note that
* this lazy locking also has the effect of lazily forcing
* cache coherency; without the lock acquisition, there's no
* guarantee that modification of arenas[ind] by another thread
* would be seen on this CPU for an arbitrary amount of time.
*
* In general, this approach to modifying a synchronized value
* isn't a good idea, but in this case we only ever modify the
* value once, so things work out well.
*/
ret = arenas[ind];
if (ret == NULL) {
/*
* Avoid races with another thread that may have already
* initialized arenas[ind].
*/
malloc_mutex_lock(&arenas_mtx);
if (arenas[ind] == NULL)
ret = arenas_extend((unsigned)ind);
else
ret = arenas[ind];
malloc_mutex_unlock(&arenas_mtx);
}
} else
ret = arenas[0];
#endif
assert(ret != NULL);
return (ret);
}
#ifndef NO_TLS
/*
* Choose an arena based on a per-thread value (slow-path code only, called
* only by choose_arena()).
*/
static arena_t *
choose_arena_hard(void)
{
arena_t *ret;
assert(__isthreaded);
/* Assign one of the arenas to this thread, in a round-robin fashion. */
malloc_mutex_lock(&arenas_mtx);
ret = arenas[next_arena];
if (ret == NULL)
ret = arenas_extend(next_arena);
if (ret == NULL) {
/*
* Make sure that this function never returns NULL, so that
* choose_arena() doesn't have to check for a NULL return
* value.
*/
ret = arenas[0];
}
next_arena = (next_arena + 1) % narenas;
malloc_mutex_unlock(&arenas_mtx);
arenas_map = ret;
return (ret);
}
#endif
static inline int
arena_chunk_comp(arena_chunk_t *a, arena_chunk_t *b)
{
assert(a != NULL);
assert(b != NULL);
if ((uintptr_t)a < (uintptr_t)b)
return (-1);
else if (a == b)
return (0);
else
return (1);
}
/* Generate red-black tree code for arena chunks. */
RB_GENERATE_STATIC(arena_chunk_tree_s, arena_chunk_s, link, arena_chunk_comp);
static inline void *
arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin)
{
void *ret;
unsigned i, mask, bit, regind;
assert(run->magic == ARENA_RUN_MAGIC);
for (i = run->regs_minelm; i < REGS_MASK_NELMS; i++) {
mask = run->regs_mask[i];
if (mask != 0) {
/* Usable allocation found. */
bit = ffs(mask) - 1;
regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
ret = (void *)&((char *)run)[bin->reg0_offset
+ (bin->reg_size * regind)];
/* Clear bit. */
mask ^= (1 << bit);
run->regs_mask[i] = mask;
return (ret);
} else {
/*
* Make a note that nothing before this element
* contains a free region.
*/
run->regs_minelm = i + 1;
}
}
/* Not reached. */
assert(0);
return (NULL);
}
static inline void
arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size)
{
unsigned diff, regind, elm, bit;
assert(run->magic == ARENA_RUN_MAGIC);
/*
* Avoid doing division with a variable divisor if possible. This
* single operation can reduce allocator throughput by around 20%!
*/
#define POW2_CASE(p) \
case (1 << (p)): \
regind = diff >> (p); \
break;
#define QUANTUM_CASE(n) \
case ((n) << QUANTUM_2POW_MIN): \
regind = diff / ((n) << QUANTUM_2POW_MIN); \
break;
/*
* These assertions make sure that the switch statement matches
* compile-time configuration.
*/
assert(tiny_min_2pow >= 1);
assert(QUANTUM_2POW_MIN >= 3 && QUANTUM_2POW_MIN <= 4);
assert(SMALL_MAX_2POW_DEFAULT == 9);
diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run - bin->reg0_offset);
switch (size) {
POW2_CASE(1)
POW2_CASE(2)
#if (QUANTUM_2POW_MIN > 3)
POW2_CASE(3)
#endif
QUANTUM_CASE(1)
QUANTUM_CASE(2)
QUANTUM_CASE(3)
QUANTUM_CASE(4)
QUANTUM_CASE(5)
QUANTUM_CASE(6)
QUANTUM_CASE(7)
QUANTUM_CASE(8)
QUANTUM_CASE(9)
QUANTUM_CASE(10)
QUANTUM_CASE(11)
QUANTUM_CASE(12)
QUANTUM_CASE(13)
QUANTUM_CASE(14)
QUANTUM_CASE(15)
QUANTUM_CASE(16)
QUANTUM_CASE(17)
QUANTUM_CASE(18)
QUANTUM_CASE(19)
QUANTUM_CASE(20)
QUANTUM_CASE(21)
QUANTUM_CASE(22)
QUANTUM_CASE(23)
QUANTUM_CASE(24)
QUANTUM_CASE(25)
QUANTUM_CASE(26)
QUANTUM_CASE(27)
QUANTUM_CASE(28)
QUANTUM_CASE(29)
QUANTUM_CASE(30)
QUANTUM_CASE(31)
QUANTUM_CASE(32)
POW2_CASE(10)
POW2_CASE(11)
POW2_CASE(12) /* Handle up to 8 kB pages. */
default:
regind = diff / size;
}
#undef POW2_CASE
#undef QUANTUM_CASE
assert(regind < bin->nregs);
elm = regind >> (SIZEOF_INT_2POW + 3);
if (elm < run->regs_minelm)
run->regs_minelm = elm;
bit = regind - (elm << (SIZEOF_INT_2POW + 3));
assert((run->regs_mask[elm] & (1 << bit)) == 0);
run->regs_mask[elm] |= (1 << bit);
}
static void
arena_run_split(arena_t *arena, arena_run_t *run, bool large, size_t size)
{
arena_chunk_t *chunk;
unsigned run_ind, map_offset, total_pages, need_pages;
unsigned i, log2_run_pages, run_pages;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
>> pagesize_2pow);
assert(chunk->map[run_ind].free);
total_pages = chunk->map[run_ind].npages;
need_pages = (size >> pagesize_2pow);
assert(chunk->map[run_ind].free);
assert(chunk->map[run_ind].large == false);
assert(chunk->map[run_ind].npages == total_pages);
/* Split enough pages from the front of run to fit allocation size. */
map_offset = run_ind;
for (i = 0; i < need_pages; i++) {
chunk->map[map_offset + i].free = false;
chunk->map[map_offset + i].large = large;
chunk->map[map_offset + i].npages = need_pages;
chunk->map[map_offset + i].pos = i;
}
/* Update map for trailing pages. */
map_offset += need_pages;
while (map_offset < run_ind + total_pages) {
log2_run_pages = ffs(map_offset) - 1;
run_pages = (1 << log2_run_pages);
chunk->map[map_offset].free = true;
chunk->map[map_offset].large = false;
chunk->map[map_offset].npages = run_pages;
chunk->nfree_runs[log2_run_pages]++;
map_offset += run_pages;
}
chunk->pages_used += (size >> pagesize_2pow);
}
static arena_chunk_t *
arena_chunk_alloc(arena_t *arena)
{
arena_chunk_t *chunk;
unsigned i, j, header_npages, pow2_header_npages, map_offset;
unsigned log2_run_pages, run_pages;
size_t header_size;
chunk = (arena_chunk_t *)chunk_alloc(chunk_size);
if (chunk == NULL)
return (NULL);
chunk->arena = arena;
RB_INSERT(arena_chunk_tree_s, &arena->chunks, chunk);
/*
* Claim that no pages are in use, since the header is merely overhead.
*/
chunk->pages_used = 0;
memset(&chunk->nfree_runs, 0, sizeof(chunk->nfree_runs));
header_size = (size_t)((uintptr_t)&chunk->map[arena_chunk_maplen]
- (uintptr_t)chunk);
if (header_size % pagesize != 0) {
/* Round up to the nearest page boundary. */
header_size += pagesize - (header_size % pagesize);
}
header_npages = header_size >> pagesize_2pow;
pow2_header_npages = pow2_ceil(header_npages);
/*
* Iteratively mark runs as in use, until we've spoken for the entire
* header.
*/
map_offset = 0;
for (i = 0; header_npages > 0; i++) {
if ((pow2_header_npages >> i) <= header_npages) {
for (j = 0; j < (pow2_header_npages >> i); j++) {
chunk->map[map_offset + j].free = false;
chunk->map[map_offset + j].large = false;
chunk->map[map_offset + j].npages =
(pow2_header_npages >> i);
chunk->map[map_offset + j].pos = j;
}
header_npages -= (pow2_header_npages >> i);
map_offset += (pow2_header_npages >> i);
}
}
/*
* Finish initializing map. The chunk header takes up some space at
* the beginning of the chunk, which we just took care of by
* "allocating" the leading pages.
*/
while (map_offset < (chunk_size >> pagesize_2pow)) {
log2_run_pages = ffs(map_offset) - 1;
run_pages = (1 << log2_run_pages);
chunk->map[map_offset].free = true;
chunk->map[map_offset].large = false;
chunk->map[map_offset].npages = run_pages;
chunk->nfree_runs[log2_run_pages]++;
map_offset += run_pages;
}
return (chunk);
}
static void
arena_chunk_dealloc(arena_chunk_t *chunk)
{
RB_REMOVE(arena_chunk_tree_s, &chunk->arena->chunks, chunk);
chunk_dealloc((void *)chunk, chunk_size);
}
static void
arena_bin_run_promote(arena_t *arena, arena_bin_t *bin, arena_run_t *run,
size_t size)
{
assert(bin == run->bin);
/* Promote. */
assert(run->free_min > run->nfree);
assert(run->quartile < RUN_Q100);
run->quartile++;
#ifdef MALLOC_STATS
bin->stats.npromote++;
#endif
/* Re-file run. */
switch (run->quartile) {
case RUN_QINIT:
assert(0);
break;
case RUN_Q0:
qr_before_insert((arena_run_t *)&bin->runs0, run, link);
run->free_max = bin->nregs - 1;
run->free_min = (bin->nregs >> 1) + 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q25:
qr_remove(run, link);
qr_before_insert((arena_run_t *)&bin->runs25, run,
link);
run->free_max = ((bin->nregs >> 2) * 3) - 1;
run->free_min = (bin->nregs >> 2) + 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q50:
qr_remove(run, link);
qr_before_insert((arena_run_t *)&bin->runs50, run,
link);
run->free_max = (bin->nregs >> 1) - 1;
run->free_min = 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q75:
/*
* Skip RUN_Q75 during promotion from RUN_Q50.
* Separate handling of RUN_Q75 and RUN_Q100 allows us
* to keep completely full runs in RUN_Q100, thus
* guaranteeing that runs in RUN_Q75 are only mostly
* full. This provides a method for avoiding a linear
* search for non-full runs, which avoids some
* pathological edge cases.
*/
run->quartile++;
/* Fall through. */
case RUN_Q100:
qr_remove(run, link);
assert(bin->runcur == run);
bin->runcur = NULL;
run->free_max = 0;
run->free_min = 0;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
default:
assert(0);
break;
}
}
static void
arena_bin_run_demote(arena_t *arena, arena_bin_t *bin, arena_run_t *run,
size_t size)
{
assert(bin == run->bin);
/* Demote. */
assert(run->free_max < run->nfree);
assert(run->quartile > RUN_QINIT);
run->quartile--;
#ifdef MALLOC_STATS
bin->stats.ndemote++;
#endif
/* Re-file run. */
switch (run->quartile) {
case RUN_QINIT:
qr_remove(run, link);
#ifdef MALLOC_STATS
bin->stats.curruns--;
#endif
if (bin->runcur == run)
bin->runcur = NULL;
#ifdef MALLOC_DEBUG
run->magic = 0;
#endif
arena_run_dalloc(arena, run, bin->run_size);
break;
case RUN_Q0:
qr_remove(run, link);
qr_before_insert((arena_run_t *)&bin->runs0, run, link);
run->free_max = bin->nregs - 1;
run->free_min = (bin->nregs >> 1) + 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q25:
qr_remove(run, link);
qr_before_insert((arena_run_t *)&bin->runs25, run,
link);
run->free_max = ((bin->nregs >> 2) * 3) - 1;
run->free_min = (bin->nregs >> 2) + 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q50:
qr_remove(run, link);
qr_before_insert((arena_run_t *)&bin->runs50, run,
link);
run->free_max = (bin->nregs >> 1) - 1;
run->free_min = 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q75:
qr_before_insert((arena_run_t *)&bin->runs75, run,
link);
run->free_max = (bin->nregs >> 2) - 1;
run->free_min = 1;
assert(run->nfree <= run->free_max);
assert(run->nfree >= run->free_min);
break;
case RUN_Q100:
default:
assert(0);
break;
}
}
static arena_run_t *
arena_run_alloc(arena_t *arena, bool large, size_t size)
{
arena_run_t *run;
unsigned min_ind, i, j;
arena_chunk_t *chunk;
#ifndef NDEBUG
int rep = 0;
#endif
assert(size <= arena_maxclass);
AGAIN:
#ifndef NDEBUG
rep++;
assert(rep <= 2);
#endif
/*
* Search through arena's chunks in address order for a run that is
* large enough. Look for a precise fit, but do not pass up a chunk
* that has a run which is large enough to split.
*/
min_ind = ffs(size >> pagesize_2pow) - 1;
RB_FOREACH(chunk, arena_chunk_tree_s, &arena->chunks) {
for (i = min_ind;
i < (opt_chunk_2pow - pagesize_2pow);
i++) {
if (chunk->nfree_runs[i] > 0) {
arena_chunk_map_t *map = chunk->map;
/* Scan chunk's map for free run. */
for (j = 0;
j < arena_chunk_maplen;
j += map[j].npages) {
if (map[j].free
&& map[j].npages == (1 << i))
{/*<----------------------------*/
run = (arena_run_t *)&((char *)chunk)[j
<< pagesize_2pow];
assert(chunk->nfree_runs[i] > 0);
chunk->nfree_runs[i]--;
/* Update page map. */
arena_run_split(arena, run, large, size);
return (run);
}/*---------------------------->*/
}
/* Not reached. */
assert(0);
}
}
}
/* No usable runs. Allocate a new chunk, then try again. */
if (arena_chunk_alloc(arena) == NULL)
return (NULL);
goto AGAIN;
}
static void
arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size)
{
arena_chunk_t *chunk;
unsigned run_ind, buddy_ind, base_run_ind, run_pages, log2_run_pages;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
>> pagesize_2pow);
run_pages = (size >> pagesize_2pow);
log2_run_pages = ffs(run_pages) - 1;
assert(run_pages > 0);
/* Subtract pages from count of pages used in chunk. */
chunk->pages_used -= run_pages;
/* Mark run as deallocated. */
chunk->map[run_ind].free = true;
chunk->map[run_ind].large = false;
chunk->map[run_ind].npages = run_pages;
/*
* Tell the kernel that we don't need the data in this run, but only if
* requested via runtime configuration.
*/
if (opt_hint) {
madvise(run, size, MADV_FREE);
#ifdef MALLOC_STATS
arena->stats.nmadvise += (size >> pagesize_2pow);
#endif
}
/*
* Iteratively coalesce with buddies. Conceptually, the buddy scheme
* induces a tree on the set of pages. If we know the number of pages
* in the subtree rooted at the current node, we can quickly determine
* whether a run is the left or right buddy, and then calculate the
* buddy's index.
*/
for (;
(run_pages = (1 << log2_run_pages)) < arena_chunk_maplen;
log2_run_pages++) {
if (((run_ind >> log2_run_pages) & 1) == 0) {
/* Current run precedes its buddy. */
buddy_ind = run_ind + run_pages;
base_run_ind = run_ind;
} else {
/* Current run follows its buddy. */
buddy_ind = run_ind - run_pages;
base_run_ind = buddy_ind;
}
if (chunk->map[buddy_ind].free == false
|| chunk->map[buddy_ind].npages != run_pages)
break;
assert(chunk->nfree_runs[log2_run_pages] > 0);
chunk->nfree_runs[log2_run_pages]--;
/* Coalesce. */
chunk->map[base_run_ind].npages = (run_pages << 1);
/* Update run_ind to be the beginning of the coalesced run. */
run_ind = base_run_ind;
}
chunk->nfree_runs[log2_run_pages]++;
/* Free pages, to the extent possible. */
if (chunk->pages_used == 0) {
/* This chunk is completely unused now, so deallocate it. */
arena_chunk_dealloc(chunk);
}
}
static arena_run_t *
arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin, size_t size)
{
arena_run_t *run;
unsigned i, remainder;
/* Look for a usable run. */
if ((run = qr_next((arena_run_t *)&bin->runs50, link))
!= (arena_run_t *)&bin->runs50
|| (run = qr_next((arena_run_t *)&bin->runs25, link))
!= (arena_run_t *)&bin->runs25
|| (run = qr_next((arena_run_t *)&bin->runs0, link))
!= (arena_run_t *)&bin->runs0
|| (run = qr_next((arena_run_t *)&bin->runs75, link))
!= (arena_run_t *)&bin->runs75) {
/* run is guaranteed to have available space. */
qr_remove(run, link);
return (run);
}
/* No existing runs have any space available. */
/* Allocate a new run. */
run = arena_run_alloc(arena, false, bin->run_size);
if (run == NULL)
return (NULL);
/* Initialize run internals. */
qr_new(run, link);
run->bin = bin;
for (i = 0; i < (bin->nregs >> (SIZEOF_INT_2POW + 3)); i++)
run->regs_mask[i] = UINT_MAX;
remainder = bin->nregs % (1 << (SIZEOF_INT_2POW + 3));
if (remainder != 0) {
run->regs_mask[i] = (UINT_MAX >> ((1 << (SIZEOF_INT_2POW + 3))
- remainder));
i++;
}
for (; i < REGS_MASK_NELMS; i++)
run->regs_mask[i] = 0;
run->regs_minelm = 0;
run->nfree = bin->nregs;
run->quartile = RUN_QINIT;
run->free_max = bin->nregs;
run->free_min = ((bin->nregs >> 2) * 3) + 1;
#ifdef MALLOC_DEBUG
run->magic = ARENA_RUN_MAGIC;
#endif
#ifdef MALLOC_STATS
bin->stats.nruns++;
bin->stats.curruns++;
if (bin->stats.curruns > bin->stats.highruns)
bin->stats.highruns = bin->stats.curruns;
#endif
return (run);
}
/* bin->runcur must have space available before this function is called. */
static inline void *
arena_bin_malloc_easy(arena_t *arena, arena_bin_t *bin, arena_run_t *run,
size_t size)
{
void *ret;
assert(run->magic == ARENA_RUN_MAGIC);
assert(run->nfree > 0);
ret = arena_run_reg_alloc(run, bin);
assert(ret != NULL);
run->nfree--;
if (run->nfree < run->free_min) {
/* Promote run to higher fullness quartile. */
arena_bin_run_promote(arena, bin, run, size);
}
return (ret);
}
/* Re-fill bin->runcur, then call arena_bin_malloc_easy(). */
static void *
arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin, size_t size)
{
assert(bin->runcur == NULL || bin->runcur->quartile == RUN_Q100);
bin->runcur = arena_bin_nonfull_run_get(arena, bin, size);
if (bin->runcur == NULL)
return (NULL);
assert(bin->runcur->magic == ARENA_RUN_MAGIC);
assert(bin->runcur->nfree > 0);
return (arena_bin_malloc_easy(arena, bin, bin->runcur, size));
}
static void *
arena_malloc(arena_t *arena, size_t size)
{
void *ret;
assert(arena != NULL);
assert(arena->magic == ARENA_MAGIC);
assert(size != 0);
assert(QUANTUM_CEILING(size) <= arena_maxclass);
if (size <= bin_maxclass) {
arena_bin_t *bin;
arena_run_t *run;
/* Small allocation. */
if (size < small_min) {
/* Tiny. */
size = pow2_ceil(size);
bin = &arena->bins[ffs(size >> (tiny_min_2pow + 1))];
#ifdef MALLOC_STATS
/*
* Bin calculation is always correct, but we may need to
* fix size for the purposes of stats accuracy.
*/
if (size < (1 << tiny_min_2pow))
size = (1 << tiny_min_2pow);
#endif
} else if (size <= small_max) {
/* Quantum-spaced. */
size = QUANTUM_CEILING(size);
bin = &arena->bins[ntbins + (size >> opt_quantum_2pow)
- 1];
} else {
/* Sub-page. */
size = pow2_ceil(size);
bin = &arena->bins[ntbins + nqbins
+ (ffs(size >> opt_small_max_2pow) - 2)];
}
assert(size == bin->reg_size);
malloc_mutex_lock(&arena->mtx);
if ((run = bin->runcur) != NULL)
ret = arena_bin_malloc_easy(arena, bin, run, size);
else
ret = arena_bin_malloc_hard(arena, bin, size);
#ifdef MALLOC_STATS
bin->stats.nrequests++;
#endif
} else {
/* Medium allocation. */
size = pow2_ceil(size);
malloc_mutex_lock(&arena->mtx);
ret = (void *)arena_run_alloc(arena, true, size);
#ifdef MALLOC_STATS
arena->stats.large_nrequests++;
#endif
}
#ifdef MALLOC_STATS
arena->stats.nmalloc++;
if (ret != NULL)
arena->stats.allocated += size;
#endif
malloc_mutex_unlock(&arena->mtx);
if (opt_junk && ret != NULL)
memset(ret, 0xa5, size);
else if (opt_zero && ret != NULL)
memset(ret, 0, size);
return (ret);
}
/* Return the size of the allocation pointed to by ptr. */
static size_t
arena_salloc(const void *ptr)
{
size_t ret;
arena_chunk_t *chunk;
uint32_t pageind;
arena_chunk_map_t mapelm;
assert(ptr != NULL);
assert(ptr != &nil);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
/*
* No arena data structures that we query here can change in a way that
* affects this function, so we don't need to lock.
*/
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
mapelm = chunk->map[pageind];
assert(mapelm.free == false);
if (mapelm.large == false) {
arena_run_t *run;
pageind -= mapelm.pos;
run = (arena_run_t *)&((char *)chunk)[pageind << pagesize_2pow];
assert(run->magic == ARENA_RUN_MAGIC);
ret = run->bin->reg_size;
} else
ret = mapelm.npages << pagesize_2pow;
return (ret);
}
static void *
arena_ralloc(void *ptr, size_t size, size_t oldsize)
{
void *ret;
/* Avoid moving the allocation if the size class would not change. */
if (size < small_min) {
if (oldsize < small_min &&
ffs(pow2_ceil(size) >> (tiny_min_2pow + 1))
== ffs(pow2_ceil(oldsize) >> (tiny_min_2pow + 1)))
goto IN_PLACE;
} else if (size <= small_max) {
if (oldsize >= small_min && oldsize <= small_max &&
(QUANTUM_CEILING(size) >> opt_quantum_2pow)
== (QUANTUM_CEILING(oldsize) >> opt_quantum_2pow))
goto IN_PLACE;
} else {
if (oldsize > small_max &&
pow2_ceil(size) == pow2_ceil(oldsize))
goto IN_PLACE;
}
/*
* If we get here, then size and oldsize are different enough that we
* need to use a different size class. In that case, fall back to
* allocating new space and copying.
*/
ret = arena_malloc(choose_arena(), size);
if (ret == NULL)
return (NULL);
if (size < oldsize)
memcpy(ret, ptr, size);
else
memcpy(ret, ptr, oldsize);
idalloc(ptr);
return (ret);
IN_PLACE:
if (opt_junk && size < oldsize)
memset(&((char *)ptr)[size], 0x5a, oldsize - size);
else if (opt_zero && size > oldsize)
memset(&((char *)ptr)[size], 0, size - oldsize);
return (ptr);
}
static void
arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
{
unsigned pageind;
arena_chunk_map_t mapelm;
size_t size;
assert(arena != NULL);
assert(arena->magic == ARENA_MAGIC);
assert(chunk->arena == arena);
assert(ptr != NULL);
assert(ptr != &nil);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
mapelm = chunk->map[pageind];
assert(mapelm.free == false);
if (mapelm.large == false) {
arena_run_t *run;
arena_bin_t *bin;
/* Small allocation. */
pageind -= mapelm.pos;
run = (arena_run_t *)&((char *)chunk)[pageind << pagesize_2pow];
assert(run->magic == ARENA_RUN_MAGIC);
bin = run->bin;
size = bin->reg_size;
if (opt_junk)
memset(ptr, 0x5a, size);
malloc_mutex_lock(&arena->mtx);
arena_run_reg_dalloc(run, bin, ptr, size);
run->nfree++;
if (run->nfree > run->free_max) {
/* Demote run to lower fullness quartile. */
arena_bin_run_demote(arena, bin, run, size);
}
} else {
/* Medium allocation. */
size = mapelm.npages << pagesize_2pow;
if (opt_junk)
memset(ptr, 0x5a, size);
malloc_mutex_lock(&arena->mtx);
arena_run_dalloc(arena, (arena_run_t *)ptr, size);
}
#ifdef MALLOC_STATS
arena->stats.allocated -= size;
#endif
malloc_mutex_unlock(&arena->mtx);
}
static bool
arena_new(arena_t *arena)
{
unsigned i;
arena_bin_t *bin;
size_t pow2_size, run_size;
malloc_mutex_init(&arena->mtx);
#ifdef MALLOC_STATS
memset(&arena->stats, 0, sizeof(arena_stats_t));
#endif
/* Initialize chunks. */
RB_INIT(&arena->chunks);
/* Initialize bins. */
/* (2^n)-spaced tiny bins. */
for (i = 0; i < ntbins; i++) {
bin = &arena->bins[i];
bin->runcur = NULL;
qr_new((arena_run_t *)&bin->runs0, link);
qr_new((arena_run_t *)&bin->runs25, link);
qr_new((arena_run_t *)&bin->runs50, link);
qr_new((arena_run_t *)&bin->runs75, link);
bin->reg_size = (1 << (tiny_min_2pow + i));
/*
* Calculate how large of a run to allocate. Make sure that at
* least RUN_MIN_REGS regions fit in the run.
*/
run_size = bin->reg_size << RUN_MIN_REGS_2POW;
if (run_size < pagesize)
run_size = pagesize;
if (run_size > (pagesize << RUN_MAX_PAGES_2POW))
run_size = (pagesize << RUN_MAX_PAGES_2POW);
if (run_size > arena_maxclass)
run_size = arena_maxclass;
bin->run_size = run_size;
assert(run_size >= sizeof(arena_run_t));
bin->nregs = (run_size - sizeof(arena_run_t)) / bin->reg_size;
if (bin->nregs > (REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3))) {
/* Take care not to overflow regs_mask. */
bin->nregs = REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3);
}
bin->reg0_offset = run_size - (bin->nregs * bin->reg_size);
#ifdef MALLOC_STATS
memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
#endif
}
/* Quantum-spaced bins. */
for (; i < ntbins + nqbins; i++) {
bin = &arena->bins[i];
bin->runcur = NULL;
qr_new((arena_run_t *)&bin->runs0, link);
qr_new((arena_run_t *)&bin->runs25, link);
qr_new((arena_run_t *)&bin->runs50, link);
qr_new((arena_run_t *)&bin->runs75, link);
bin->reg_size = quantum * (i - ntbins + 1);
/*
* Calculate how large of a run to allocate. Make sure that at
* least RUN_MIN_REGS regions fit in the run.
*/
pow2_size = pow2_ceil(quantum * (i - ntbins + 1));
run_size = (pow2_size << RUN_MIN_REGS_2POW);
if (run_size < pagesize)
run_size = pagesize;
if (run_size > (pagesize << RUN_MAX_PAGES_2POW))
run_size = (pagesize << RUN_MAX_PAGES_2POW);
if (run_size > arena_maxclass)
run_size = arena_maxclass;
bin->run_size = run_size;
bin->nregs = (run_size - sizeof(arena_run_t)) / bin->reg_size;
assert(bin->nregs <= REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3));
bin->reg0_offset = run_size - (bin->nregs * bin->reg_size);
#ifdef MALLOC_STATS
memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
#endif
}
/* (2^n)-spaced sub-page bins. */
for (; i < ntbins + nqbins + nsbins; i++) {
bin = &arena->bins[i];
bin->runcur = NULL;
qr_new((arena_run_t *)&bin->runs0, link);
qr_new((arena_run_t *)&bin->runs25, link);
qr_new((arena_run_t *)&bin->runs50, link);
qr_new((arena_run_t *)&bin->runs75, link);
bin->reg_size = (small_max << (i - (ntbins + nqbins) + 1));
/*
* Calculate how large of a run to allocate. Make sure that at
* least RUN_MIN_REGS regions fit in the run.
*/
run_size = bin->reg_size << RUN_MIN_REGS_2POW;
if (run_size < pagesize)
run_size = pagesize;
if (run_size > (pagesize << RUN_MAX_PAGES_2POW))
run_size = (pagesize << RUN_MAX_PAGES_2POW);
if (run_size > arena_maxclass)
run_size = arena_maxclass;
bin->run_size = run_size;
bin->nregs = (run_size - sizeof(arena_run_t)) / bin->reg_size;
assert(bin->nregs <= REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3));
bin->reg0_offset = run_size - (bin->nregs * bin->reg_size);
#ifdef MALLOC_STATS
memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
#endif
}
#ifdef MALLOC_DEBUG
arena->magic = ARENA_MAGIC;
#endif
return (false);
}
/* Create a new arena and insert it into the arenas array at index ind. */
static arena_t *
arenas_extend(unsigned ind)
{
arena_t *ret;
/* Allocate enough space for trailing bins. */
ret = (arena_t *)base_alloc(sizeof(arena_t)
+ (sizeof(arena_bin_t) * (ntbins + nqbins + nsbins - 1)));
if (ret != NULL && arena_new(ret) == false) {
arenas[ind] = ret;
return (ret);
}
/* Only reached if there is an OOM error. */
/*
* OOM here is quite inconvenient to propagate, since dealing with it
* would require a check for failure in the fast path. Instead, punt
* by using arenas[0]. In practice, this is an extremely unlikely
* failure.
*/
malloc_printf("%s: (malloc) Error initializing arena\n",
_getprogname());
if (opt_abort)
abort();
return (arenas[0]);
}
/*
* End arena.
*/
/******************************************************************************/
/*
* Begin general internal functions.
*/
static void *
huge_malloc(size_t size)
{
void *ret;
size_t csize;
chunk_node_t *node;
/* Allocate one or more contiguous chunks for this request. */
csize = CHUNK_CEILING(size);
if (csize == 0) {
/* size is large enough to cause size_t wrap-around. */
return (NULL);
}
/* Allocate a chunk node with which to track the chunk. */
node = base_chunk_node_alloc();
if (node == NULL)
return (NULL);
ret = chunk_alloc(csize);
if (ret == NULL) {
base_chunk_node_dealloc(node);
return (NULL);
}
/* Insert node into chunks. */
node->chunk = ret;
node->size = csize;
malloc_mutex_lock(&chunks_mtx);
RB_INSERT(chunk_tree_s, &huge, node);
#ifdef MALLOC_STATS
huge_nmalloc++;
huge_allocated += csize;
#endif
malloc_mutex_unlock(&chunks_mtx);
if (opt_junk && ret != NULL)
memset(ret, 0xa5, csize);
else if (opt_zero && ret != NULL)
memset(ret, 0, csize);
return (ret);
}
static void *
huge_ralloc(void *ptr, size_t size, size_t oldsize)
{
void *ret;
/* Avoid moving the allocation if the size class would not change. */
if (oldsize > arena_maxclass &&
CHUNK_CEILING(size) == CHUNK_CEILING(oldsize))
return (ptr);
/*
* If we get here, then size and oldsize are different enough that we
* need to use a different size class. In that case, fall back to
* allocating new space and copying.
*/
ret = huge_malloc(size);
if (ret == NULL)
return (NULL);
if (CHUNK_ADDR2BASE(ptr) == ptr) {
/* The old allocation is a chunk. */
if (size < oldsize)
memcpy(ret, ptr, size);
else
memcpy(ret, ptr, oldsize);
} else {
/* The old allocation is a region. */
assert(oldsize < size);
memcpy(ret, ptr, oldsize);
}
idalloc(ptr);
return (ret);
}
static void
huge_dalloc(void *ptr)
{
chunk_node_t key;
chunk_node_t *node;
malloc_mutex_lock(&chunks_mtx);
/* Extract from tree of huge allocations. */
key.chunk = ptr;
node = RB_FIND(chunk_tree_s, &huge, &key);
assert(node != NULL);
assert(node->chunk == ptr);
RB_REMOVE(chunk_tree_s, &huge, node);
#ifdef MALLOC_STATS
/* Update counters. */
huge_ndalloc++;
huge_allocated -= node->size;
#endif
malloc_mutex_unlock(&chunks_mtx);
/* Unmap chunk. */
#ifdef USE_BRK
if (opt_junk)
memset(node->chunk, 0x5a, node->size);
#endif
chunk_dealloc(node->chunk, node->size);
base_chunk_node_dealloc(node);
}
static void *
imalloc(size_t size)
{
void *ret;
assert(size != 0);
if (size <= arena_maxclass)
ret = arena_malloc(choose_arena(), size);
else
ret = huge_malloc(size);
return (ret);
}
static void *
ipalloc(size_t alignment, size_t size)
{
void *ret;
size_t pow2_size;
/*
* Round up to the nearest power of two that is >= alignment and
* >= size.
*/
if (size > alignment)
pow2_size = pow2_ceil(size);
else
pow2_size = alignment;
pow2_size = QUANTUM_CEILING(pow2_size);
if (pow2_size < size) {
/* size_t overflow. */
return (NULL);
}
if (pow2_size <= arena_maxclass)
ret = arena_malloc(choose_arena(), pow2_size);
else {
if (alignment <= chunk_size)
ret = huge_malloc(size);
else {
size_t chunksize, alloc_size, offset;
chunk_node_t *node;
/*
* This allocation requires alignment that is even
* larger than chunk alignment. This means that
* huge_malloc() isn't good enough.
*
* Allocate almost twice as many chunks as are demanded
* by the size or alignment, in order to assure the
* alignment can be achieved, then unmap leading and
* trailing chunks.
*/
chunksize = CHUNK_CEILING(size);
if (size >= alignment)
alloc_size = chunksize + alignment - chunk_size;
else
alloc_size = (alignment << 1) - chunk_size;
/*
* Allocate a chunk node with which to track the chunk.
*/
node = base_chunk_node_alloc();
if (node == NULL)
return (NULL);
ret = chunk_alloc(alloc_size);
if (ret == NULL) {
base_chunk_node_dealloc(node);
return (NULL);
}
offset = (uintptr_t)ret & (alignment - 1);
assert(offset % chunk_size == 0);
assert(offset < alloc_size);
if (offset == 0) {
/* Trim trailing space. */
chunk_dealloc((void *)((uintptr_t)ret
+ chunksize), alloc_size - chunksize);
} else {
size_t trailsize;
/* Trim leading space. */
chunk_dealloc(ret, alignment - offset);
ret = (void *)((uintptr_t)ret + (alignment
- offset));
trailsize = alloc_size - (alignment - offset)
- chunksize;
if (trailsize != 0) {
/* Trim trailing space. */
assert(trailsize < alloc_size);
chunk_dealloc((void *)((uintptr_t)ret
+ chunksize), trailsize);
}
}
/* Insert node into chunks. */
node->chunk = ret;
node->size = chunksize;
malloc_mutex_lock(&chunks_mtx);
RB_INSERT(chunk_tree_s, &huge, node);
#ifdef MALLOC_STATS
huge_allocated += size;
#endif
malloc_mutex_unlock(&chunks_mtx);
if (opt_junk)
memset(ret, 0xa5, chunksize);
else if (opt_zero)
memset(ret, 0, chunksize);
}
}
assert(((uintptr_t)ret & (alignment - 1)) == 0);
return (ret);
}
static void *
icalloc(size_t size)
{
void *ret;
if (size <= arena_maxclass) {
ret = arena_malloc(choose_arena(), size);
if (ret == NULL)
return (NULL);
memset(ret, 0, size);
} else {
/*
* The virtual memory system provides zero-filled pages, so
* there is no need to do so manually, unless opt_junk is
* enabled, in which case huge_malloc() fills huge allocations
* with junk.
*/
ret = huge_malloc(size);
if (ret == NULL)
return (NULL);
if (opt_junk)
memset(ret, 0, size);
#ifdef USE_BRK
else if ((uintptr_t)ret >= (uintptr_t)brk_base
&& (uintptr_t)ret < (uintptr_t)brk_max) {
/*
* This may be a re-used brk chunk. Therefore, zero
* the memory.
*/
memset(ret, 0, size);
}
#endif
}
return (ret);
}
static size_t
isalloc(const void *ptr)
{
size_t ret;
arena_chunk_t *chunk;
assert(ptr != NULL);
assert(ptr != &nil);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
/* Region. */
assert(chunk->arena->magic == ARENA_MAGIC);
ret = arena_salloc(ptr);
} else {
chunk_node_t *node, key;
/* Chunk (huge allocation). */
malloc_mutex_lock(&chunks_mtx);
/* Extract from tree of huge allocations. */
key.chunk = (void *)ptr;
node = RB_FIND(chunk_tree_s, &huge, &key);
assert(node != NULL);
ret = node->size;
malloc_mutex_unlock(&chunks_mtx);
}
return (ret);
}
static void *
iralloc(void *ptr, size_t size)
{
void *ret;
size_t oldsize;
assert(ptr != NULL);
assert(ptr != &nil);
assert(size != 0);
oldsize = isalloc(ptr);
if (size <= arena_maxclass)
ret = arena_ralloc(ptr, size, oldsize);
else
ret = huge_ralloc(ptr, size, oldsize);
return (ret);
}
static void
idalloc(void *ptr)
{
arena_chunk_t *chunk;
assert(ptr != NULL);
assert(ptr != &nil);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
/* Region. */
#ifdef MALLOC_STATS
malloc_mutex_lock(&chunk->arena->mtx);
chunk->arena->stats.ndalloc++;
malloc_mutex_unlock(&chunk->arena->mtx);
#endif
arena_dalloc(chunk->arena, chunk, ptr);
} else
huge_dalloc(ptr);
}
static void
malloc_print_stats(void)
{
if (opt_print_stats) {
malloc_printf("___ Begin malloc statistics ___\n");
malloc_printf("Number of CPUs: %u\n", ncpus);
malloc_printf("Number of arenas: %u\n", narenas);
malloc_printf("Chunk size: %zu (2^%zu)\n", chunk_size,
opt_chunk_2pow);
malloc_printf("Quantum size: %zu (2^%zu)\n", quantum,
opt_quantum_2pow);
malloc_printf("Max small size: %zu\n", small_max);
malloc_printf("Pointer size: %u\n", sizeof(void *));
malloc_printf("Assertions %s\n",
#ifdef NDEBUG
"disabled"
#else
"enabled"
#endif
);
#ifdef MALLOC_STATS
{
size_t allocated, total;
unsigned i;
arena_t *arena;
/* Calculate and print allocated/total stats. */
/* arenas. */
for (i = 0, allocated = 0; i < narenas; i++) {
if (arenas[i] != NULL) {
malloc_mutex_lock(&arenas[i]->mtx);
allocated += arenas[i]->stats.allocated;
malloc_mutex_unlock(&arenas[i]->mtx);
}
}
/* huge. */
malloc_mutex_lock(&chunks_mtx);
allocated += huge_allocated;
total = stats_chunks.curchunks * chunk_size;
malloc_mutex_unlock(&chunks_mtx);
malloc_printf("Allocated: %zu, space used: %zu\n",
allocated, total);
/* Print chunk stats. */
{
chunk_stats_t chunks_stats;
malloc_mutex_lock(&chunks_mtx);
chunks_stats = stats_chunks;
malloc_mutex_unlock(&chunks_mtx);
malloc_printf("\nchunks:\n");
malloc_printf(" %13s%13s%13s\n", "nchunks",
"highchunks", "curchunks");
malloc_printf(" %13llu%13lu%13lu\n",
chunks_stats.nchunks,
chunks_stats.highchunks,
chunks_stats.curchunks);
}
/* Print chunk stats. */
malloc_printf("\nhuge:\n");
malloc_printf("%12s %12s %12s\n",
"nmalloc", "ndalloc", "allocated");
malloc_printf("%12llu %12llu %12zu\n",
huge_nmalloc, huge_ndalloc, huge_allocated);
/* Print stats for each arena. */
for (i = 0; i < narenas; i++) {
arena = arenas[i];
if (arena != NULL) {
malloc_printf(
"\narenas[%u] statistics:\n", i);
malloc_mutex_lock(&arena->mtx);
stats_print(arena);
malloc_mutex_unlock(&arena->mtx);
}
}
}
#endif /* #ifdef MALLOC_STATS */
malloc_printf("--- End malloc statistics ---\n");
}
}
/*
* FreeBSD's pthreads implementation calls malloc(3), so the malloc
* implementation has to take pains to avoid infinite recursion during
* initialization.
*/
static inline bool
malloc_init(void)
{
if (malloc_initialized == false)
return (malloc_init_hard());
return (false);
}
static bool
malloc_init_hard(void)
{
unsigned i, j;
int linklen;
char buf[PATH_MAX + 1];
const char *opts;
malloc_mutex_lock(&init_lock);
if (malloc_initialized) {
/*
* Another thread initialized the allocator before this one
* acquired init_lock.
*/
malloc_mutex_unlock(&init_lock);
return (false);
}
/* Get number of CPUs. */
{
int mib[2];
size_t len;
mib[0] = CTL_HW;
mib[1] = HW_NCPU;
len = sizeof(ncpus);
if (sysctl(mib, 2, &ncpus, &len, (void *) 0, 0) == -1) {
/* Error. */
ncpus = 1;
}
}
/* Get page size. */
{
long result;
result = sysconf(_SC_PAGESIZE);
assert(result != -1);
pagesize = (unsigned) result;
/*
* We assume that pagesize is a power of 2 when calculating
* pagesize_2pow.
*/
assert(((result - 1) & result) == 0);
pagesize_2pow = ffs(result) - 1;
}
for (i = 0; i < 3; i++) {
/* Get runtime configuration. */
switch (i) {
case 0:
if ((linklen = readlink("/etc/malloc.conf", buf,
sizeof(buf) - 1)) != -1) {
/*
* Use the contents of the "/etc/malloc.conf"
* symbolic link's name.
*/
buf[linklen] = '\0';
opts = buf;
} else {
/* No configuration specified. */
buf[0] = '\0';
opts = buf;
}
break;
case 1:
if (issetugid() == 0 && (opts =
getenv("MALLOC_OPTIONS")) != NULL) {
/*
* Do nothing; opts is already initialized to
* the value of the MALLOC_OPTIONS environment
* variable.
*/
} else {
/* No configuration specified. */
buf[0] = '\0';
opts = buf;
}
break;
case 2:
if (_malloc_options != NULL) {
/*
* Use options that were compiled into the program.
*/
opts = _malloc_options;
} else {
/* No configuration specified. */
buf[0] = '\0';
opts = buf;
}
break;
default:
/* NOTREACHED */
assert(false);
}
for (j = 0; opts[j] != '\0'; j++) {
switch (opts[j]) {
case 'a':
opt_abort = false;
break;
case 'A':
opt_abort = true;
break;
case 'h':
opt_hint = false;
break;
case 'H':
opt_hint = true;
break;
case 'j':
opt_junk = false;
break;
case 'J':
opt_junk = true;
break;
case 'k':
/*
* Run fullness quartile limits don't have
* enough resolution if there are too few
* regions for the largest bin size classes.
*/
if (opt_chunk_2pow > pagesize_2pow + 3)
opt_chunk_2pow--;
break;
case 'K':
if (opt_chunk_2pow < CHUNK_2POW_MAX)
opt_chunk_2pow++;
break;
case 'n':
opt_narenas_lshift--;
break;
case 'N':
opt_narenas_lshift++;
break;
case 'p':
opt_print_stats = false;
break;
case 'P':
opt_print_stats = true;
break;
case 'q':
if (opt_quantum_2pow > QUANTUM_2POW_MIN)
opt_quantum_2pow--;
break;
case 'Q':
if (opt_quantum_2pow < pagesize_2pow - 1)
opt_quantum_2pow++;
break;
case 's':
if (opt_small_max_2pow > QUANTUM_2POW_MIN)
opt_small_max_2pow--;
break;
case 'S':
if (opt_small_max_2pow < pagesize_2pow - 1)
opt_small_max_2pow++;
break;
case 'u':
opt_utrace = false;
break;
case 'U':
opt_utrace = true;
break;
case 'v':
opt_sysv = false;
break;
case 'V':
opt_sysv = true;
break;
case 'x':
opt_xmalloc = false;
break;
case 'X':
opt_xmalloc = true;
break;
case 'z':
opt_zero = false;
break;
case 'Z':
opt_zero = true;
break;
default:
malloc_printf("%s: (malloc) Unsupported"
" character in malloc options: '%c'\n",
_getprogname(), opts[j]);
}
}
}
/* Take care to call atexit() only once. */
if (opt_print_stats) {
/* Print statistics at exit. */
atexit(malloc_print_stats);
}
/* Set variables according to the value of opt_small_max_2pow. */
if (opt_small_max_2pow < opt_quantum_2pow)
opt_small_max_2pow = opt_quantum_2pow;
small_max = (1 << opt_small_max_2pow);
/* Set bin-related variables. */
bin_maxclass = (pagesize >> 1);
if (pagesize_2pow > RUN_MIN_REGS_2POW + 1)
tiny_min_2pow = pagesize_2pow - (RUN_MIN_REGS_2POW + 1);
else
tiny_min_2pow = 1;
assert(opt_quantum_2pow >= tiny_min_2pow);
ntbins = opt_quantum_2pow - tiny_min_2pow;
assert(ntbins <= opt_quantum_2pow);
nqbins = (small_max >> opt_quantum_2pow);
nsbins = pagesize_2pow - opt_small_max_2pow - 1;
/* Set variables according to the value of opt_quantum_2pow. */
quantum = (1 << opt_quantum_2pow);
quantum_mask = quantum - 1;
if (ntbins > 0)
small_min = (quantum >> 1) + 1;
else
small_min = 1;
assert(small_min <= quantum);
/* Set variables according to the value of opt_chunk_2pow. */
chunk_size = (1 << opt_chunk_2pow);
chunk_size_mask = chunk_size - 1;
arena_chunk_maplen = (1 << (opt_chunk_2pow - pagesize_2pow));
arena_maxclass = (chunk_size >> 1);
UTRACE(0, 0, 0);
#ifdef MALLOC_STATS
memset(&stats_chunks, 0, sizeof(chunk_stats_t));
#endif
/* Various sanity checks that regard configuration. */
assert(quantum >= sizeof(void *));
assert(quantum <= pagesize);
assert(chunk_size >= pagesize);
assert(quantum * 4 <= chunk_size);
/* Initialize chunks data. */
malloc_mutex_init(&chunks_mtx);
RB_INIT(&huge);
#ifdef USE_BRK
brk_base = sbrk(0);
brk_prev = brk_base;
brk_max = brk_base;
#endif
#ifdef MALLOC_STATS
huge_nmalloc = 0;
huge_ndalloc = 0;
huge_allocated = 0;
#endif
RB_INIT(&old_chunks);
/* Initialize base allocation data structures. */
#ifdef MALLOC_STATS
base_total = 0;
#endif
#ifdef USE_BRK
/*
* Do special brk allocation here, since the base chunk doesn't really
* need to be chunk-aligned.
*/
{
void *brk_cur;
intptr_t incr;
do {
/* Get the current end of brk. */
brk_cur = sbrk(0);
/*
* Calculate how much padding is necessary to
* chunk-align the end of brk. Don't worry about
* brk_cur not being chunk-aligned though.
*/
incr = (intptr_t)chunk_size
- (intptr_t)CHUNK_ADDR2OFFSET(brk_cur);
brk_prev = sbrk(incr);
if (brk_prev == brk_cur) {
/* Success. */
break;
}
} while (brk_prev != (void *)-1);
base_chunk = brk_cur;
base_next_addr = base_chunk;
base_past_addr = (void *)((uintptr_t)base_chunk + incr);
#ifdef MALLOC_STATS
base_total += incr;
stats_chunks.nchunks = 1;
stats_chunks.curchunks = 1;
stats_chunks.highchunks = 1;
#endif
}
#else
/*
* The first base chunk will be allocated when needed by base_alloc().
*/
base_chunk = NULL;
base_next_addr = NULL;
base_past_addr = NULL;
#endif
base_chunk_nodes = NULL;
malloc_mutex_init(&base_mtx);
if (ncpus > 1) {
/*
* For SMP systems, create four times as many arenas as there
* are CPUs by default.
*/
opt_narenas_lshift += 2;
}
/* Determine how many arenas to use. */
narenas = ncpus;
if (opt_narenas_lshift > 0) {
if ((narenas << opt_narenas_lshift) > narenas)
narenas <<= opt_narenas_lshift;
/*
* Make sure not to exceed the limits of what base_malloc()
* can handle.
*/
if (narenas * sizeof(arena_t *) > chunk_size)
narenas = chunk_size / sizeof(arena_t *);
} else if (opt_narenas_lshift < 0) {
if ((narenas << opt_narenas_lshift) < narenas)
narenas <<= opt_narenas_lshift;
/* Make sure there is at least one arena. */
if (narenas == 0)
narenas = 1;
}
#ifdef NO_TLS
if (narenas > 1) {
static const unsigned primes[] = {1, 3, 5, 7, 11, 13, 17, 19,
23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83,
89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211,
223, 227, 229, 233, 239, 241, 251, 257, 263};
unsigned i, nprimes, parenas;
/*
* Pick a prime number of hash arenas that is more than narenas
* so that direct hashing of pthread_self() pointers tends to
* spread allocations evenly among the arenas.
*/
assert((narenas & 1) == 0); /* narenas must be even. */
nprimes = (sizeof(primes) >> SIZEOF_INT_2POW);
parenas = primes[nprimes - 1]; /* In case not enough primes. */
for (i = 1; i < nprimes; i++) {
if (primes[i] > narenas) {
parenas = primes[i];
break;
}
}
narenas = parenas;
}
#endif
#ifndef NO_TLS
next_arena = 0;
#endif
/* Allocate and initialize arenas. */
arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas);
if (arenas == NULL) {
malloc_mutex_unlock(&init_lock);
return (true);
}
/*
* Zero the array. In practice, this should always be pre-zeroed,
* since it was just mmap()ed, but let's be sure.
*/
memset(arenas, 0, sizeof(arena_t *) * narenas);
/*
* Initialize one arena here. The rest are lazily created in
* arena_choose_hard().
*/
arenas_extend(0);
if (arenas[0] == NULL) {
malloc_mutex_unlock(&init_lock);
return (true);
}
malloc_mutex_init(&arenas_mtx);
malloc_initialized = true;
malloc_mutex_unlock(&init_lock);
return (false);
}
/*
* End general internal functions.
*/
/******************************************************************************/
/*
* Begin malloc(3)-compatible functions.
*/
void *
malloc(size_t size)
{
void *ret;
if (malloc_init()) {
ret = NULL;
goto RETURN;
}
if (size == 0) {
if (opt_sysv == false)
ret = (void *)&nil;
else
ret = NULL;
goto RETURN;
}
ret = imalloc(size);
RETURN:
if (ret == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in malloc(%zu):"
" out of memory\n", _getprogname(), size);
abort();
}
errno = ENOMEM;
}
UTRACE(0, size, ret);
return (ret);
}
int
posix_memalign(void **memptr, size_t alignment, size_t size)
{
int ret;
void *result;
if (malloc_init())
result = NULL;
else {
/* Make sure that alignment is a large enough power of 2. */
if (((alignment - 1) & alignment) != 0
|| alignment < sizeof(void *)) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" posix_memalign(%zu, %zu):"
" invalid alignment\n",
_getprogname(), alignment, size);
abort();
}
result = NULL;
ret = EINVAL;
goto RETURN;
}
result = ipalloc(alignment, size);
}
if (result == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" posix_memalign(%zu, %zu): out of memory\n",
_getprogname(), alignment, size);
abort();
}
ret = ENOMEM;
goto RETURN;
}
*memptr = result;
ret = 0;
RETURN:
UTRACE(0, size, result);
return (ret);
}
void *
calloc(size_t num, size_t size)
{
void *ret;
size_t num_size;
if (malloc_init()) {
ret = NULL;
goto RETURN;
}
num_size = num * size;
if (num_size == 0) {
if (opt_sysv == false)
ret = (void *)&nil;
else
ret = NULL;
goto RETURN;
/*
* Try to avoid division here. We know that it isn't possible to
* overflow during multiplication if neither operand uses any of the
* most significant half of the bits in a size_t.
*/
} else if (((num | size) & (SIZE_T_MAX << (sizeof(size_t) << 2)))
&& (num_size / size != num)) {
/* size_t overflow. */
ret = NULL;
goto RETURN;
}
ret = icalloc(num_size);
RETURN:
if (ret == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" calloc(%zu, %zu): out of memory\n",
_getprogname(), num, size);
abort();
}
errno = ENOMEM;
}
UTRACE(0, num_size, ret);
return (ret);
}
void *
realloc(void *ptr, size_t size)
{
void *ret;
if (size != 0) {
if (ptr != &nil && ptr != NULL) {
assert(malloc_initialized);
ret = iralloc(ptr, size);
if (ret == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" ralloc(%p, %zu): out of memory\n",
_getprogname(), ptr, size);
abort();
}
errno = ENOMEM;
}
} else {
if (malloc_init())
ret = NULL;
else
ret = imalloc(size);
if (ret == NULL) {
if (opt_xmalloc) {
malloc_printf("%s: (malloc) Error in"
" ralloc(%p, %zu): out of memory\n",
_getprogname(), ptr, size);
abort();
}
errno = ENOMEM;
}
}
} else {
if (ptr != &nil && ptr != NULL)
idalloc(ptr);
ret = (void *)&nil;
}
UTRACE(ptr, size, ret);
return (ret);
}
void
free(void *ptr)
{
UTRACE(ptr, 0, 0);
if (ptr != &nil && ptr != NULL) {
assert(malloc_initialized);
idalloc(ptr);
}
}
/*
* End malloc(3)-compatible functions.
*/
/******************************************************************************/
/*
* Begin non-standard functions.
*/
size_t
malloc_usable_size(const void *ptr)
{
assert(ptr != NULL);
if (ptr == &nil)
return (0);
else
return (isalloc(ptr));
}
/*
* End non-standard functions.
*/
/******************************************************************************/
/*
* Begin library-private functions, used by threading libraries for protection
* of malloc during fork(). These functions are only called if the program is
* running in threaded mode, so there is no need to check whether the program
* is threaded here.
*/
void
_malloc_prefork(void)
{
unsigned i;
/* Acquire all mutexes in a safe order. */
malloc_mutex_lock(&arenas_mtx);
for (i = 0; i < narenas; i++) {
if (arenas[i] != NULL)
malloc_mutex_lock(&arenas[i]->mtx);
}
malloc_mutex_unlock(&arenas_mtx);
malloc_mutex_lock(&base_mtx);
malloc_mutex_lock(&chunks_mtx);
}
void
_malloc_postfork(void)
{
unsigned i;
/* Release all mutexes, now that fork() has completed. */
malloc_mutex_unlock(&chunks_mtx);
malloc_mutex_unlock(&base_mtx);
malloc_mutex_lock(&arenas_mtx);
for (i = 0; i < narenas; i++) {
if (arenas[i] != NULL)
malloc_mutex_unlock(&arenas[i]->mtx);
}
malloc_mutex_unlock(&arenas_mtx);
}
/*
* End library-private functions.
*/
/******************************************************************************/