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ebc87e7e0b
freebsd-dev/lib/libc/stdlib/malloc.c
Jason Evans ebc87e7e0b Add the 'D' and 'M' run time options, and use them to control whether 
memory is acquired from the system via sbrk(2) and/or mmap(2).  By default,
use sbrk(2) only, in order to support traditional use of resource limits.
Additionally, when both options are enabled, prefer the data segment to
anonymous mappings, in order to coexist better with large file mappings
in applications on 32-bit platforms.  This change has the potential to
increase memory fragmentation due to the linear nature of the data
segment, but from a performance perspective this is mitigated by the use
of madvise(2). [1]

Add the ability to interpret integer prefixes in MALLOC_OPTIONS
processing.  For example, MALLOC_OPTIONS=lllllllll can now be specified as
MALLOC_OPTIONS=9l.

Reported by:	[1] rwatson
Design review:	[1] alc, peter, rwatson
2007-12-27 23:29:44 +00:00

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/*-
* Copyright (C) 2006,2007 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),
* 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 |
* | | 12 kB |
* | | ... |
* | | 1012 kB |
* | | 1016 kB |
* | | 1020 kB |
* |=====================================|
* | Huge | 1 MB |
* | | 2 MB |
* | | 3 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.
*
*******************************************************************************
*/
/*
* MALLOC_PRODUCTION disables assertions and statistics gathering. It also
* defaults the A and J runtime options to off. These settings are appropriate
* for production systems.
*/
/* #define MALLOC_PRODUCTION */
#ifndef MALLOC_PRODUCTION
/*
* MALLOC_DEBUG enables assertions and other sanity checks, and disables
* inline functions.
*/
# define MALLOC_DEBUG
/* MALLOC_STATS enables statistics calculation. */
# define MALLOC_STATS
#endif
/*
* MALLOC_LAZY_FREE enables the use of a per-thread vector of slots that free()
* can atomically stuff object pointers into. This can reduce arena lock
* contention.
*/
#define MALLOC_LAZY_FREE
/*
* MALLOC_BALANCE enables monitoring of arena lock contention and dynamically
* re-balances arena load if exponentially averaged contention exceeds a
* certain threshold.
*/
#define MALLOC_BALANCE
/*
* MALLOC_DSS enables use of sbrk(2) to allocate chunks from the data storage
* segment (DSS). In an ideal world, this functionality would be completely
* unnecessary, but we are burdened by history and the lack of resource limits
* for anonymous mapped memory.
*/
#define MALLOC_DSS
#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 <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include "un-namespace.h"
#ifdef MALLOC_DEBUG
# ifdef NDEBUG
# undef NDEBUG
# endif
#else
# 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_2POW 2
# define CPU_SPINWAIT __asm__ volatile("pause")
#endif
#ifdef __ia64__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR_2POW 3
#endif
#ifdef __alpha__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR_2POW 3
# define NO_TLS
#endif
#ifdef __sparc64__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR_2POW 3
# define NO_TLS
#endif
#ifdef __amd64__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR_2POW 3
# define CPU_SPINWAIT __asm__ volatile("pause")
#endif
#ifdef __arm__
# define QUANTUM_2POW_MIN 3
# define SIZEOF_PTR_2POW 2
# define NO_TLS
#endif
#ifdef __powerpc__
# define QUANTUM_2POW_MIN 4
# define SIZEOF_PTR_2POW 2
#endif
#define SIZEOF_PTR (1U << SIZEOF_PTR_2POW)
/* sizeof(int) == (1U << 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
#ifdef NO_TLS
/* MALLOC_BALANCE requires TLS. */
# ifdef MALLOC_BALANCE
# undef MALLOC_BALANCE
# endif
/* MALLOC_LAZY_FREE requires TLS. */
# ifdef MALLOC_LAZY_FREE
# undef MALLOC_LAZY_FREE
# endif
#endif
/*
* Size and alignment of memory chunks that are allocated by the OS's virtual
* memory system.
*/
#define CHUNK_2POW_DEFAULT 20
/*
* 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)(1U << CACHELINE_2POW))
/* Smallest size class to support. */
#define TINY_MIN_2POW 1
/*
* 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 (1U << SMALL_MAX_2POW_DEFAULT)
/*
* 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 there is one bit 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_size << (3+RUN_BFP))
*/
#define RUN_BFP 12
/* \/ Implicit binary fixed point. */
#define RUN_MAX_OVRHD 0x0000003dU
#define RUN_MAX_OVRHD_RELAX 0x00001800U
/* Put a cap on small object run size. This overrides RUN_MAX_OVRHD. */
#define RUN_MAX_SMALL_2POW 15
#define RUN_MAX_SMALL (1U << RUN_MAX_SMALL_2POW)
#ifdef MALLOC_LAZY_FREE
/* Default size of each arena's lazy free cache. */
# define LAZY_FREE_2POW_DEFAULT 8
/*
* Number of pseudo-random probes to conduct before considering the cache to
* be overly full. It takes on average n probes to detect fullness of
* (n-1)/n. However, we are effectively doing multiple non-independent
* trials (each deallocation is a trial), so the actual average threshold
* for clearing the cache is somewhat lower.
*/
# define LAZY_FREE_NPROBES 5
#endif
/*
* Hyper-threaded CPUs may need a special instruction inside spin loops in
* order to yield to another virtual CPU. If no such instruction is defined
* above, make CPU_SPINWAIT a no-op.
*/
#ifndef CPU_SPINWAIT
# define CPU_SPINWAIT
#endif
/*
* Adaptive spinning must eventually switch to blocking, in order to avoid the
* potential for priority inversion deadlock. Backing off past a certain point
* can actually waste time.
*/
#define SPIN_LIMIT_2POW 11
/*
* Conversion from spinning to blocking is expensive; we use (1U <<
* BLOCK_COST_2POW) to estimate how many more times costly blocking is than
* worst-case spinning.
*/
#define BLOCK_COST_2POW 4
#ifdef MALLOC_BALANCE
/*
* We use an exponential moving average to track recent lock contention,
* where the size of the history window is N, and alpha=2/(N+1).
*
* Due to integer math rounding, very small values here can cause
* substantial degradation in accuracy, thus making the moving average decay
* faster than it would with precise calculation.
*/
# define BALANCE_ALPHA_INV_2POW 9
/*
* Threshold value for the exponential moving contention average at which to
* re-assign a thread.
*/
# define BALANCE_THRESHOLD_DEFAULT (1U << (SPIN_LIMIT_2POW-4))
#endif
/******************************************************************************/
/*
* Mutexes based on spinlocks. We can't use normal pthread spinlocks in all
* places, because they require malloc()ed memory, which causes bootstrapping
* issues in some cases.
*/
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 runs reused by extracting them from the runs tree for
* this bin's size class.
*/
uint64_t reruns;
/* 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 {
/* Number of bytes currently mapped. */
size_t mapped;
/* Per-size-category statistics. */
size_t allocated_small;
uint64_t nmalloc_small;
uint64_t ndalloc_small;
size_t allocated_large;
uint64_t nmalloc_large;
uint64_t ndalloc_large;
#ifdef MALLOC_BALANCE
/* Number of times this arena reassigned a thread due to contention. */
uint64_t nbalance;
#endif
};
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 {
/*
* Number of pages in run. For a free run that has never been touched,
* this is NPAGES_EMPTY for the central pages, which allows us to avoid
* zero-filling untouched pages for calloc().
*/
#define NPAGES_EMPTY ((uint32_t)0x0U)
uint32_t npages;
/*
* Position within run. For a free run, this is POS_EMPTY/POS_FREE for
* the first and last pages. The special values make it possible to
* quickly coalesce free runs. POS_EMPTY indicates that the run has
* never been touched, which allows us to avoid zero-filling untouched
* pages for calloc().
*
* This is the limiting factor for chunksize; there can be at most 2^31
* pages in a run.
*
* POS_EMPTY is assumed by arena_run_dalloc() to be less than POS_FREE.
*/
#define POS_EMPTY ((uint32_t)0xfffffffeU)
#define POS_FREE ((uint32_t)0xffffffffU)
uint32_t pos;
};
/* 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;
/*
* Every time a free run larger than this value is created/coalesced,
* this value is increased. The only way that the value decreases is if
* arena_run_alloc() fails to find a free run as large as advertised by
* this value.
*/
uint32_t max_frun_npages;
/*
* Every time a free run that starts at an earlier page than this value
* is created/coalesced, this value is decreased. It is reset in a
* similar fashion to max_frun_npages.
*/
uint32_t min_frun_ind;
/*
* Map of pages within chunk that keeps track of free/large/small. For
* free runs, only the map entries for the first and last pages are
* kept up to date, so that free runs can be quickly coalesced.
*/
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 trees. */
RB_ENTRY(arena_run_s) link;
#ifdef MALLOC_DEBUG
uint32_t magic;
# define ARENA_RUN_MAGIC 0x384adf93
#endif
/* Bin this run is associated with. */
arena_bin_t *bin;
/* Index of first element that might have a free region. */
unsigned regs_minelm;
/* Number of free regions in run. */
unsigned nfree;
/* Bitmask of in-use regions (0: in use, 1: free). */
unsigned regs_mask[1]; /* Dynamically sized. */
};
typedef struct arena_run_tree_s arena_run_tree_t;
RB_HEAD(arena_run_tree_s, arena_run_s);
struct arena_bin_s {
/*
* 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;
/* 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;
/* Number of elements in a run's regs_mask for this bin's size class. */
uint32_t regs_mask_nelms;
/* 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 lock be locked. */
pthread_mutex_t lock;
#ifdef MALLOC_STATS
arena_stats_t stats;
#endif
/*
* Tree of chunks this arena manages.
*/
arena_chunk_tree_t chunks;
/*
* 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. This caching is disabled by opt_hint.
*
* 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;
#ifdef MALLOC_BALANCE
/*
* The arena load balancing machinery needs to keep track of how much
* lock contention there is. This value is exponentially averaged.
*/
uint32_t contention;
#endif
#ifdef MALLOC_LAZY_FREE
/*
* Deallocation of small objects can be lazy, in which case free_cache
* stores pointers to those objects that have not yet been deallocated.
* In order to avoid lock contention, slots are chosen randomly. Empty
* slots contain NULL.
*/
void **free_cache;
#endif
/*
* 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.
*/
/* Number of CPUs. */
static unsigned ncpus;
/* VM page size. */
static size_t pagesize;
static size_t pagesize_mask;
static size_t 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;
/* Various quantum-related settings. */
static size_t quantum;
static size_t quantum_mask; /* (quantum - 1). */
/* Various chunk-related settings. */
static size_t chunksize;
static size_t chunksize_mask; /* (chunksize - 1). */
static unsigned chunk_npages;
static unsigned arena_chunk_header_npages;
static size_t arena_maxclass; /* Max size class for arenas. */
/********/
/*
* 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 MALLOC_DSS
/*
* Protects sbrk() calls. This must be separate from chunks_mtx, since
* base_pages_alloc() also uses sbrk(), but cannot lock chunks_mtx (doing so
* could cause recursive lock acquisition).
*/
static malloc_mutex_t dss_mtx;
/* Base address of the DSS. */
static void *dss_base;
/* Current end of the DSS, or ((void *)-1) if the DSS is exhausted. */
static void *dss_prev;
/* Current upper limit on DSS addresses. */
static void *dss_max;
#endif
#ifdef MALLOC_STATS
/* Huge allocation statistics. */
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 pages that are being used for internal memory allocations. These
* pages are carved up in cacheline-size quanta, so that there is no chance of
* false cache line sharing.
*/
static void *base_pages;
static void *base_next_addr;
static void *base_past_addr; /* Addr immediately past base_pages. */
static chunk_node_t *base_chunk_nodes; /* LIFO cache of chunk nodes. */
static malloc_mutex_t base_mtx;
#ifdef MALLOC_STATS
static size_t base_mapped;
#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
# ifdef MALLOC_BALANCE
static unsigned narenas_2pow;
# else
static unsigned next_arena;
# endif
#endif
static pthread_mutex_t arenas_lock; /* 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 MALLOC_PRODUCTION
static bool opt_abort = true;
static bool opt_junk = true;
#else
static bool opt_abort = false;
static bool opt_junk = false;
#endif
#ifdef MALLOC_DSS
static bool opt_dss = true;
static bool opt_mmap = false;
#endif
static bool opt_hint = false;
#ifdef MALLOC_LAZY_FREE
static int opt_lazy_free_2pow = LAZY_FREE_2POW_DEFAULT;
#endif
#ifdef MALLOC_BALANCE
static uint64_t opt_balance_threshold = BALANCE_THRESHOLD_DEFAULT;
#endif
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 int 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 *mutex);
static bool malloc_spin_init(pthread_mutex_t *lock);
static void wrtmessage(const char *p1, const char *p2, const char *p3,
const char *p4);
#ifdef MALLOC_STATS
static void malloc_printf(const char *format, ...);
#endif
static char *umax2s(uintmax_t x, char *s);
static bool base_pages_alloc(size_t minsize);
static void *base_alloc(size_t size);
static void *base_calloc(size_t number, 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, size_t size,
bool zero);
static arena_chunk_t *arena_chunk_alloc(arena_t *arena);
static void arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk);
static arena_run_t *arena_run_alloc(arena_t *arena, size_t size, bool zero);
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);
static void *arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin);
static size_t arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size);
static void *arena_malloc(arena_t *arena, size_t size, bool zero);
static void *arena_palloc(arena_t *arena, size_t alignment, size_t size,
size_t alloc_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, bool zero);
static void *huge_palloc(size_t alignment, 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. We can't use normal pthread mutexes in all places, because
* they require malloc()ed memory, which causes bootstrapping issues in some
* cases.
*/
static void
malloc_mutex_init(malloc_mutex_t *mutex)
{
static const spinlock_t lock = _SPINLOCK_INITIALIZER;
mutex->lock = lock;
}
static inline void
malloc_mutex_lock(malloc_mutex_t *mutex)
{
if (__isthreaded)
_SPINLOCK(&mutex->lock);
}
static inline void
malloc_mutex_unlock(malloc_mutex_t *mutex)
{
if (__isthreaded)
_SPINUNLOCK(&mutex->lock);
}
/*
* End mutex.
*/
/******************************************************************************/
/*
* Begin spin lock. Spin locks here are actually adaptive mutexes that block
* after a period of spinning, because unbounded spinning would allow for
* priority inversion.
*/
/*
* We use an unpublished interface to initialize pthread mutexes with an
* allocation callback, in order to avoid infinite recursion.
*/
int _pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
void *(calloc_cb)(size_t, size_t));
__weak_reference(_pthread_mutex_init_calloc_cb_stub,
_pthread_mutex_init_calloc_cb);
int
_pthread_mutex_init_calloc_cb_stub(pthread_mutex_t *mutex,
void *(calloc_cb)(size_t, size_t))
{
return (0);
}
static bool
malloc_spin_init(pthread_mutex_t *lock)
{
if (_pthread_mutex_init_calloc_cb(lock, base_calloc) != 0)
return (true);
return (false);
}
static inline unsigned
malloc_spin_lock(pthread_mutex_t *lock)
{
unsigned ret = 0;
if (__isthreaded) {
if (_pthread_mutex_trylock(lock) != 0) {
unsigned i;
volatile unsigned j;
/* Exponentially back off. */
for (i = 1; i <= SPIN_LIMIT_2POW; i++) {
for (j = 0; j < (1U << i); j++)
ret++;
CPU_SPINWAIT;
if (_pthread_mutex_trylock(lock) == 0)
return (ret);
}
/*
* Spinning failed. Block until the lock becomes
* available, in order to avoid indefinite priority
* inversion.
*/
_pthread_mutex_lock(lock);
assert((ret << BLOCK_COST_2POW) != 0);
return (ret << BLOCK_COST_2POW);
}
}
return (ret);
}
static inline void
malloc_spin_unlock(pthread_mutex_t *lock)
{
if (__isthreaded)
_pthread_mutex_unlock(lock);
}
/*
* End spin lock.
*/
/******************************************************************************/
/*
* Begin Utility functions/macros.
*/
/* Return the chunk address for allocation address a. */
#define CHUNK_ADDR2BASE(a) \
((void *)((uintptr_t)(a) & ~chunksize_mask))
/* Return the chunk offset of address a. */
#define CHUNK_ADDR2OFFSET(a) \
((size_t)((uintptr_t)(a) & chunksize_mask))
/* Return the smallest chunk multiple that is >= s. */
#define CHUNK_CEILING(s) \
(((s) + chunksize_mask) & ~chunksize_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)
/* Return the smallest pagesize multiple that is >= s. */
#define PAGE_CEILING(s) \
(((s) + pagesize_mask) & ~pagesize_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);
}
#if (defined(MALLOC_LAZY_FREE) || defined(MALLOC_BALANCE))
/*
* Use a simple linear congruential pseudo-random number generator:
*
* prn(y) = (a*x + c) % m
*
* where the following constants ensure maximal period:
*
* a == Odd number (relatively prime to 2^n), and (a-1) is a multiple of 4.
* c == Odd number (relatively prime to 2^n).
* m == 2^32
*
* See Knuth's TAOCP 3rd Ed., Vol. 2, pg. 17 for details on these constraints.
*
* This choice of m has the disadvantage that the quality of the bits is
* proportional to bit position. For example. the lowest bit has a cycle of 2,
* the next has a cycle of 4, etc. For this reason, we prefer to use the upper
* bits.
*/
# define PRN_DEFINE(suffix, var, a, c) \
static inline void \
sprn_##suffix(uint32_t seed) \
{ \
var = seed; \
} \
\
static inline uint32_t \
prn_##suffix(uint32_t lg_range) \
{ \
uint32_t ret, x; \
\
assert(lg_range > 0); \
assert(lg_range <= 32); \
\
x = (var * (a)) + (c); \
var = x; \
ret = x >> (32 - lg_range); \
\
return (ret); \
}
# define SPRN(suffix, seed) sprn_##suffix(seed)
# define PRN(suffix, lg_range) prn_##suffix(lg_range)
#endif
/*
* Define PRNGs, one for each purpose, in order to avoid auto-correlation
* problems.
*/
#ifdef MALLOC_LAZY_FREE
/* Define the per-thread PRNG used for lazy deallocation. */
static __thread uint32_t lazy_free_x;
PRN_DEFINE(lazy_free, lazy_free_x, 12345, 12347)
#endif
#ifdef MALLOC_BALANCE
/* Define the PRNG used for arena assignment. */
static __thread uint32_t balance_x;
PRN_DEFINE(balance, balance_x, 1297, 1301)
#endif
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;
#ifdef MALLOC_STATS
/*
* 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, "", "", "");
}
#endif
/*
* We don't want to depend on vsnprintf() for production builds, since that can
* cause unnecessary bloat for static binaries. umax2s() provides minimal
* integer printing functionality, so that malloc_printf() use can be limited to
* MALLOC_STATS code.
*/
#define UMAX2S_BUFSIZE 21
static char *
umax2s(uintmax_t x, char *s)
{
unsigned i;
/* Make sure UMAX2S_BUFSIZE is large enough. */
assert(sizeof(uintmax_t) <= 8);
i = UMAX2S_BUFSIZE - 1;
s[i] = '\0';
do {
i--;
s[i] = "0123456789"[x % 10];
x /= 10;
} while (x > 0);
return (&s[i]);
}
/******************************************************************************/
#ifdef MALLOC_DSS
static inline bool
base_pages_alloc_dss(size_t minsize)
{
/*
* Do special DSS allocation here, since base allocations don't need to
* be chunk-aligned.
*/
if (dss_prev != (void *)-1) {
void *dss_cur;
intptr_t incr;
size_t csize = CHUNK_CEILING(minsize);
malloc_mutex_lock(&dss_mtx);
do {
/* Get the current end of the DSS. */
dss_cur = sbrk(0);
/*
* Calculate how much padding is necessary to
* chunk-align the end of the DSS. Don't worry about
* dss_cur not being chunk-aligned though.
*/
incr = (intptr_t)chunksize
- (intptr_t)CHUNK_ADDR2OFFSET(dss_cur);
if (incr < minsize)
incr += csize;
dss_prev = sbrk(incr);
if (dss_prev == dss_cur) {
/* Success. */
malloc_mutex_unlock(&dss_mtx);
base_pages = dss_cur;
base_next_addr = base_pages;
base_past_addr = (void *)((uintptr_t)base_pages
+ incr);
#ifdef MALLOC_STATS
base_mapped += incr;
#endif
return (false);
}
} while (dss_prev != (void *)-1);
malloc_mutex_unlock(&dss_mtx);
}
return (true);
}
#endif
static inline bool
base_pages_alloc_mmap(size_t minsize)
{
size_t csize;
assert(minsize != 0);
csize = PAGE_CEILING(minsize);
base_pages = pages_map(NULL, csize);
if (base_pages == NULL)
return (true);
base_next_addr = base_pages;
base_past_addr = (void *)((uintptr_t)base_pages + csize);
#ifdef MALLOC_STATS
base_mapped += csize;
#endif
return (false);
}
static bool
base_pages_alloc(size_t minsize)
{
#ifdef MALLOC_DSS
if (opt_dss) {
if (base_pages_alloc_dss(minsize) == false)
return (false);
}
if (opt_mmap && minsize != 0)
#endif
{
if (base_pages_alloc_mmap(minsize) == false)
return (false);
}
return (true);
}
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) {
if (base_pages_alloc(csize)) {
ret = NULL;
goto RETURN;
}
}
/* Allocate. */
ret = base_next_addr;
base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
RETURN:
malloc_mutex_unlock(&base_mtx);
return (ret);
}
static void *
base_calloc(size_t number, size_t size)
{
void *ret;
ret = base_alloc(number * size);
memset(ret, 0, number * size);
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, gap_start;
malloc_printf(
" allocated/mapped nmalloc ndalloc\n");
malloc_printf("small: %12llu %-12s %12llu %12llu\n",
arena->stats.allocated_small, "", arena->stats.nmalloc_small,
arena->stats.ndalloc_small);
malloc_printf("large: %12llu %-12s %12llu %12llu\n",
arena->stats.allocated_large, "", arena->stats.nmalloc_large,
arena->stats.ndalloc_large);
malloc_printf("total: %12llu/%-12llu %12llu %12llu\n",
arena->stats.allocated_small + arena->stats.allocated_large,
arena->stats.mapped,
arena->stats.nmalloc_small + arena->stats.nmalloc_large,
arena->stats.ndalloc_small + arena->stats.ndalloc_large);
malloc_printf("bins: bin size regs pgs requests newruns"
" reruns maxruns curruns\n");
for (i = 0, gap_start = UINT_MAX; i < ntbins + nqbins + nsbins; i++) {
if (arena->bins[i].stats.nrequests == 0) {
if (gap_start == UINT_MAX)
gap_start = i;
} else {
if (gap_start != UINT_MAX) {
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 = UINT_MAX;
}
malloc_printf(
"%13u %1s %4u %4u %3u %9llu %9llu"
" %9llu %7lu %7lu\n",
i,
i < ntbins ? "T" : i < ntbins + nqbins ? "Q" : "S",
arena->bins[i].reg_size,
arena->bins[i].nregs,
arena->bins[i].run_size >> pagesize_2pow,
arena->bins[i].stats.nrequests,
arena->bins[i].stats.nruns,
arena->bins[i].stats.reruns,
arena->bins[i].stats.highruns,
arena->bins[i].stats.curruns);
}
}
if (gap_start != UINT_MAX) {
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_message(_getprogname(),
": (malloc) Error in munmap(): ", buf, "\n");
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_message(_getprogname(),
": (malloc) Error in munmap(): ", buf, "\n");
if (opt_abort)
abort();
}
}
#ifdef MALLOC_DSS
static inline void *
chunk_alloc_dss(size_t size)
{
/*
* Try to create allocations in the DSS, in order to make full use of
* limited address space.
*/
if (dss_prev != (void *)-1) {
void *dss_cur;
intptr_t incr;
/*
* The loop is necessary to recover from races with other
* threads that are using the DSS for something other than
* malloc.
*/
malloc_mutex_lock(&dss_mtx);
do {
void *ret;
/* Get the current end of the DSS. */
dss_cur = sbrk(0);
/*
* Calculate how much padding is necessary to
* chunk-align the end of the DSS.
*/
incr = (intptr_t)size
- (intptr_t)CHUNK_ADDR2OFFSET(dss_cur);
if (incr == size) {
ret = dss_cur;
} else {
ret = (void *)((intptr_t)dss_cur + incr);
incr += size;
}
dss_prev = sbrk(incr);
if (dss_prev == dss_cur) {
/* Success. */
malloc_mutex_unlock(&dss_mtx);
dss_max = (void *)((intptr_t)ret + size);
return (ret);
}
} while (dss_prev != (void *)-1);
malloc_mutex_unlock(&dss_mtx);
}
return (NULL);
}
#endif
static inline void *
chunk_alloc_mmap(size_t size)
{
/*
* Try to over-allocate, but allow the OS to place the allocation
* anywhere. Beware of size_t wrap-around.
*/
if (size + chunksize > size) {
void *ret;
if ((ret = pages_map(NULL, size + chunksize)) != NULL) {
size_t offset = CHUNK_ADDR2OFFSET(ret);
/*
* Success. Clean up unneeded leading/trailing space.
*/
if (offset != 0) {
/* Leading space. */
pages_unmap(ret, chunksize - offset);
ret = (void *)((uintptr_t)ret + (chunksize -
offset));
/* Trailing space. */
pages_unmap((void *)((uintptr_t)ret + size),
offset);
} else {
/* Trailing space only. */
pages_unmap((void *)((uintptr_t)ret + size),
chunksize);
}
return (ret);
}
}
return (NULL);
}
static void *
chunk_alloc(size_t size)
{
void *ret, *chunk;
chunk_node_t *tchunk, *delchunk;
assert(size != 0);
assert((size & chunksize_mask) == 0);
malloc_mutex_lock(&chunks_mtx);
if (size == chunksize) {
/*
* 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 MALLOC_DSS
if (opt_dss && (uintptr_t)chunk >= (uintptr_t)dss_base
&& (uintptr_t)chunk < (uintptr_t)dss_max) {
/* Re-use a previously freed DSS chunk. */
ret = chunk;
/*
* Maintain invariant that all newly allocated
* chunks are untouched or zero-filled.
*/
memset(ret, 0, size);
goto RETURN;
}
#endif
if ((ret = pages_map(chunk, size)) != NULL) {
/* Success. */
goto RETURN;
}
}
}
#ifdef MALLOC_DSS
if (opt_dss) {
ret = chunk_alloc_dss(size);
if (ret != NULL)
goto RETURN;
}
if (opt_mmap)
#endif
{
ret = chunk_alloc_mmap(size);
if (ret != NULL)
goto RETURN;
}
/* All strategies for allocation failed. */
ret = NULL;
RETURN:
if (ret != NULL) {
chunk_node_t key;
/*
* Clean out any entries in old_chunks that overlap with the
* memory we just allocated.
*/
key.chunk = ret;
tchunk = RB_NFIND(chunk_tree_s, &old_chunks, &key);
while (tchunk != NULL
&& (uintptr_t)tchunk->chunk >= (uintptr_t)ret
&& (uintptr_t)tchunk->chunk < (uintptr_t)ret + size) {
delchunk = tchunk;
tchunk = RB_NEXT(chunk_tree_s, &old_chunks, delchunk);
RB_REMOVE(chunk_tree_s, &old_chunks, delchunk);
base_chunk_node_dealloc(delchunk);
}
}
#ifdef MALLOC_STATS
if (ret != NULL) {
stats_chunks.nchunks += (size / chunksize);
stats_chunks.curchunks += (size / chunksize);
}
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);
}
#ifdef MALLOC_DSS
static inline bool
chunk_dealloc_dss(void *chunk, size_t size)
{
chunk_node_t *node;
if ((uintptr_t)chunk >= (uintptr_t)dss_base
&& (uintptr_t)chunk < (uintptr_t)dss_max) {
void *dss_cur;
malloc_mutex_lock(&dss_mtx);
/* Get the current end of the DSS. */
dss_cur = sbrk(0);
/*
* Try to shrink the DSS if this chunk is at the end of the
* DSS. 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 (dss_cur == dss_max
&& (void *)((uintptr_t)chunk + size) == dss_max
&& sbrk(-(intptr_t)size) == dss_max) {
malloc_mutex_unlock(&dss_mtx);
if (dss_prev == dss_max) {
/* Success. */
dss_prev = (void *)((intptr_t)dss_max
- (intptr_t)size);
dss_max = dss_prev;
}
} else {
size_t offset;
malloc_mutex_unlock(&dss_mtx);
madvise(chunk, size, MADV_FREE);
/*
* 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 += chunksize) {
node = base_chunk_node_alloc();
if (node == NULL)
break;
node->chunk = (void *)((uintptr_t)chunk
+ (uintptr_t)offset);
node->size = chunksize;
RB_INSERT(chunk_tree_s, &old_chunks, node);
}
}
return (false);
}
return (true);
}
#endif
static inline void
chunk_dealloc_mmap(void *chunk, size_t size)
{
chunk_node_t *node;
pages_unmap(chunk, size);
/*
* Make a record of the chunk's address, so that the address
* range can be recycled if memory usage increases later on.
* Don't bother to create entries if (size > chunksize), since
* doing so could cause scalability issues for truly gargantuan
* objects (many gigabytes or larger).
*/
if (size == chunksize) {
node = base_chunk_node_alloc();
if (node != NULL) {
node->chunk = (void *)(uintptr_t)chunk;
node->size = chunksize;
RB_INSERT(chunk_tree_s, &old_chunks, node);
}
}
}
static void
chunk_dealloc(void *chunk, size_t size)
{
assert(chunk != NULL);
assert(CHUNK_ADDR2BASE(chunk) == chunk);
assert(size != 0);
assert((size & chunksize_mask) == 0);
malloc_mutex_lock(&chunks_mtx);
#ifdef MALLOC_DSS
if (opt_dss) {
if (chunk_dealloc_dss(chunk, size) == false)
return;
}
if (opt_mmap)
#endif
chunk_dealloc_mmap(chunk, size);
#ifdef MALLOC_STATS
stats_chunks.curchunks -= (size / chunksize);
#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();
assert(ret != NULL);
}
#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_spin_lock(&arenas_lock);
if (arenas[ind] == NULL)
ret = arenas_extend((unsigned)ind);
else
ret = arenas[ind];
malloc_spin_unlock(&arenas_lock);
}
} 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);
#ifdef MALLOC_LAZY_FREE
/*
* Seed the PRNG used for lazy deallocation. Since seeding only occurs
* on the first allocation by a thread, it is possible for a thread to
* deallocate before seeding. This is not a critical issue though,
* since it is extremely unusual for an application to to use threads
* that deallocate but *never* allocate, and because even if seeding
* never occurs for multiple threads, they will tend to drift apart
* unless some aspect of the application forces deallocation
* synchronization.
*/
SPRN(lazy_free, (uint32_t)(uintptr_t)(_pthread_self()));
#endif
#ifdef MALLOC_BALANCE
/*
* Seed the PRNG used for arena load balancing. We can get away with
* using the same seed here as for the lazy_free PRNG without
* introducing autocorrelation because the PRNG parameters are
* distinct.
*/
SPRN(balance, (uint32_t)(uintptr_t)(_pthread_self()));
#endif
if (narenas > 1) {
#ifdef MALLOC_BALANCE
unsigned ind;
ind = PRN(balance, narenas_2pow);
if ((ret = arenas[ind]) == NULL) {
malloc_spin_lock(&arenas_lock);
if ((ret = arenas[ind]) == NULL)
ret = arenas_extend(ind);
malloc_spin_unlock(&arenas_lock);
}
#else
malloc_spin_lock(&arenas_lock);
if ((ret = arenas[next_arena]) == NULL)
ret = arenas_extend(next_arena);
next_arena = (next_arena + 1) % narenas;
malloc_spin_unlock(&arenas_lock);
#endif
} else
ret = arenas[0];
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 int
arena_run_comp(arena_run_t *a, arena_run_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 runs. */
RB_GENERATE_STATIC(arena_run_tree_s, arena_run_s, link, arena_run_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);
assert(run->regs_minelm < bin->regs_mask_nelms);
/*
* Move the first check outside the loop, so that run->regs_minelm can
* be updated unconditionally, without the possibility of updating it
* multiple times.
*/
i = run->regs_minelm;
mask = run->regs_mask[i];
if (mask != 0) {
/* Usable allocation found. */
bit = ffs((int)mask) - 1;
regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
ret = (void *)(((uintptr_t)run) + bin->reg0_offset
+ (bin->reg_size * regind));
/* Clear bit. */
mask ^= (1U << bit);
run->regs_mask[i] = mask;
return (ret);
}
for (i++; i < bin->regs_mask_nelms; i++) {
mask = run->regs_mask[i];
if (mask != 0) {
/* Usable allocation found. */
bit = ffs((int)mask) - 1;
regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
ret = (void *)(((uintptr_t)run) + bin->reg0_offset
+ (bin->reg_size * regind));
/* Clear bit. */
mask ^= (1U << bit);
run->regs_mask[i] = mask;
/*
* Make a note that nothing before this element
* contains a free region.
*/
run->regs_minelm = i; /* Low payoff: + (mask == 0); */
return (ret);
}
}
/* 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)
{
/*
* 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 * size_invs[(D >> QUANTUM_2POW_MIN) - 3]) >> SIZE_INV_SHIFT
*/
#define SIZE_INV_SHIFT 21
#define SIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << QUANTUM_2POW_MIN)) + 1)
static const unsigned size_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 (QUANTUM_2POW_MIN < 4)
,
SIZE_INV(32), SIZE_INV(33), SIZE_INV(34), SIZE_INV(35),
SIZE_INV(36), SIZE_INV(37), SIZE_INV(38), SIZE_INV(39),
SIZE_INV(40), SIZE_INV(41), SIZE_INV(42), SIZE_INV(43),
SIZE_INV(44), SIZE_INV(45), SIZE_INV(46), SIZE_INV(47),
SIZE_INV(48), SIZE_INV(49), SIZE_INV(50), SIZE_INV(51),
SIZE_INV(52), SIZE_INV(53), SIZE_INV(54), SIZE_INV(55),
SIZE_INV(56), SIZE_INV(57), SIZE_INV(58), SIZE_INV(59),
SIZE_INV(60), SIZE_INV(61), SIZE_INV(62), SIZE_INV(63)
#endif
};
unsigned diff, regind, elm, bit;
assert(run->magic == ARENA_RUN_MAGIC);
assert(((sizeof(size_invs)) / sizeof(unsigned)) + 3
>= (SMALL_MAX_DEFAULT >> QUANTUM_2POW_MIN));
/*
* 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->reg0_offset);
if ((size & (size - 1)) == 0) {
/*
* log2_table allows fast division of a power of two in the
* [1..128] range.
*
* (x / divisor) becomes (x >> log2_table[divisor - 1]).
*/
static const unsigned char log2_table[] = {
0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7
};
if (size <= 128)
regind = (diff >> log2_table[size - 1]);
else if (size <= 32768)
regind = diff >> (8 + log2_table[(size >> 8) - 1]);
else {
/*
* The page size is too large for us to use the lookup
* table. Use real division.
*/
regind = diff / size;
}
} else if (size <= ((sizeof(size_invs) / sizeof(unsigned))
<< QUANTUM_2POW_MIN) + 2) {
regind = size_invs[(size >> QUANTUM_2POW_MIN) - 3] * diff;
regind >>= SIZE_INV_SHIFT;
} else {
/*
* size_invs isn't large enough to handle this size class, so
* calculate regind using actual division. This only happens
* if the user increases small_max via the 'S' runtime
* configuration option.
*/
regind = diff / size;
};
assert(diff == regind * size);
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] & (1U << bit)) == 0);
run->regs_mask[elm] |= (1U << bit);
#undef SIZE_INV
#undef SIZE_INV_SHIFT
}
static void
arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool zero)
{
arena_chunk_t *chunk;
unsigned run_ind, map_offset, total_pages, need_pages, rem_pages;
unsigned i;
uint32_t pos_beg, pos_end;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
>> pagesize_2pow);
total_pages = chunk->map[run_ind].npages;
need_pages = (size >> pagesize_2pow);
assert(need_pages > 0);
assert(need_pages <= total_pages);
rem_pages = total_pages - need_pages;
/* Split enough pages from the front of run to fit allocation size. */
map_offset = run_ind;
pos_beg = chunk->map[map_offset].pos;
pos_end = chunk->map[map_offset + total_pages - 1].pos;
if (zero == false) {
for (i = 0; i < need_pages; i++) {
chunk->map[map_offset + i].npages = need_pages;
chunk->map[map_offset + i].pos = i;
}
} else {
/*
* Handle first page specially, since we need to look for
* POS_EMPTY rather than NPAGES_EMPTY.
*/
i = 0;
if (chunk->map[map_offset + i].pos != POS_EMPTY) {
memset((void *)((uintptr_t)chunk + ((map_offset + i) <<
pagesize_2pow)), 0, pagesize);
}
chunk->map[map_offset + i].npages = need_pages;
chunk->map[map_offset + i].pos = i;
/* Handle central pages. */
for (i++; i < need_pages - 1; i++) {
if (chunk->map[map_offset + i].npages != NPAGES_EMPTY) {
memset((void *)((uintptr_t)chunk + ((map_offset
+ i) << pagesize_2pow)), 0, pagesize);
}
chunk->map[map_offset + i].npages = need_pages;
chunk->map[map_offset + i].pos = i;
}
/*
* Handle last page specially, since we need to look for
* POS_EMPTY rather than NPAGES_EMPTY.
*/
if (i < need_pages) {
if (chunk->map[map_offset + i].npages != POS_EMPTY) {
memset((void *)((uintptr_t)chunk + ((map_offset
+ i) << pagesize_2pow)), 0, pagesize);
}
chunk->map[map_offset + i].npages = need_pages;
chunk->map[map_offset + i].pos = i;
}
}
/* Keep track of trailing unused pages for later use. */
if (rem_pages > 0) {
/* Update map for trailing pages. */
map_offset += need_pages;
chunk->map[map_offset].npages = rem_pages;
chunk->map[map_offset].pos = pos_beg;
chunk->map[map_offset + rem_pages - 1].npages = rem_pages;
chunk->map[map_offset + rem_pages - 1].pos = pos_end;
}
chunk->pages_used += need_pages;
}
static arena_chunk_t *
arena_chunk_alloc(arena_t *arena)
{
arena_chunk_t *chunk;
if (arena->spare != NULL) {
chunk = arena->spare;
arena->spare = NULL;
RB_INSERT(arena_chunk_tree_s, &arena->chunks, chunk);
} else {
unsigned i;
chunk = (arena_chunk_t *)chunk_alloc(chunksize);
if (chunk == NULL)
return (NULL);
#ifdef MALLOC_STATS
arena->stats.mapped += chunksize;
#endif
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;
chunk->max_frun_npages = chunk_npages -
arena_chunk_header_npages;
chunk->min_frun_ind = arena_chunk_header_npages;
/*
* Initialize enough of the map to support one maximal free run.
*/
i = arena_chunk_header_npages;
chunk->map[i].npages = chunk_npages - arena_chunk_header_npages;
chunk->map[i].pos = POS_EMPTY;
/* Mark the free run's central pages as untouched. */
for (i++; i < chunk_npages - 1; i++)
chunk->map[i].npages = NPAGES_EMPTY;
/* Take care when (chunk_npages == 2). */
if (i < chunk_npages) {
chunk->map[i].npages = chunk_npages -
arena_chunk_header_npages;
chunk->map[i].pos = POS_EMPTY;
}
}
return (chunk);
}
static void
arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
{
/*
* Remove chunk from the chunk tree, regardless of whether this chunk
* will be cached, so that the arena does not use it.
*/
RB_REMOVE(arena_chunk_tree_s, &chunk->arena->chunks, chunk);
if (opt_hint == false) {
if (arena->spare != NULL) {
chunk_dealloc((void *)arena->spare, chunksize);
#ifdef MALLOC_STATS
arena->stats.mapped -= chunksize;
#endif
}
arena->spare = chunk;
} else {
assert(arena->spare == NULL);
chunk_dealloc((void *)chunk, chunksize);
#ifdef MALLOC_STATS
arena->stats.mapped -= chunksize;
#endif
}
}
static arena_run_t *
arena_run_alloc(arena_t *arena, size_t size, bool zero)
{
arena_chunk_t *chunk;
arena_run_t *run;
unsigned need_npages, limit_pages, compl_need_npages;
assert(size <= (chunksize - (arena_chunk_header_npages <<
pagesize_2pow)));
assert((size & pagesize_mask) == 0);
/*
* Search through arena's chunks in address order for a free run that is
* large enough. Look for the first fit.
*/
need_npages = (size >> pagesize_2pow);
limit_pages = chunk_npages - arena_chunk_header_npages;
compl_need_npages = limit_pages - need_npages;
RB_FOREACH(chunk, arena_chunk_tree_s, &arena->chunks) {
/*
* Avoid searching this chunk if there are not enough
* contiguous free pages for there to possibly be a large
* enough free run.
*/
if (chunk->pages_used <= compl_need_npages &&
need_npages <= chunk->max_frun_npages) {
arena_chunk_map_t *mapelm;
unsigned i;
unsigned max_frun_npages = 0;
unsigned min_frun_ind = chunk_npages;
assert(chunk->min_frun_ind >=
arena_chunk_header_npages);
for (i = chunk->min_frun_ind; i < chunk_npages;) {
mapelm = &chunk->map[i];
if (mapelm->pos >= POS_EMPTY) {
if (mapelm->npages >= need_npages) {
run = (arena_run_t *)
((uintptr_t)chunk + (i <<
pagesize_2pow));
/* Update page map. */
arena_run_split(arena, run,
size, zero);
return (run);
}
if (mapelm->npages >
max_frun_npages) {
max_frun_npages =
mapelm->npages;
}
if (i < min_frun_ind) {
min_frun_ind = i;
if (i < chunk->min_frun_ind)
chunk->min_frun_ind = i;
}
}
i += mapelm->npages;
}
/*
* Search failure. Reset cached chunk->max_frun_npages.
* chunk->min_frun_ind was already reset above (if
* necessary).
*/
chunk->max_frun_npages = max_frun_npages;
}
}
/*
* No usable runs. Create a new chunk from which to allocate the run.
*/
chunk = arena_chunk_alloc(arena);
if (chunk == NULL)
return (NULL);
run = (arena_run_t *)((uintptr_t)chunk + (arena_chunk_header_npages <<
pagesize_2pow));
/* Update page map. */
arena_run_split(arena, run, size, zero);
return (run);
}
static void
arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size)
{
arena_chunk_t *chunk;
unsigned run_ind, run_pages;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
>> pagesize_2pow);
assert(run_ind >= arena_chunk_header_npages);
assert(run_ind < (chunksize >> pagesize_2pow));
run_pages = (size >> pagesize_2pow);
assert(run_pages == chunk->map[run_ind].npages);
/* Subtract pages from count of pages used in chunk. */
chunk->pages_used -= run_pages;
/* Mark run as deallocated. */
assert(chunk->map[run_ind].npages == run_pages);
chunk->map[run_ind].pos = POS_FREE;
assert(chunk->map[run_ind + run_pages - 1].npages == run_pages);
chunk->map[run_ind + run_pages - 1].pos = POS_FREE;
/*
* 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);
/* Try to coalesce with neighboring runs. */
if (run_ind > arena_chunk_header_npages &&
chunk->map[run_ind - 1].pos >= POS_EMPTY) {
unsigned prev_npages;
/* Coalesce with previous run. */
prev_npages = chunk->map[run_ind - 1].npages;
/*
* The way run allocation currently works (lowest first fit),
* it is impossible for a free run to have empty (untouched)
* pages followed by dirty pages. If the run allocation policy
* changes, then we will need to account for it here.
*/
assert(chunk->map[run_ind - 1].pos != POS_EMPTY);
#if 0 /* Currently unnecessary. */
if (prev_npages > 1 && chunk->map[run_ind - 1].pos == POS_EMPTY)
chunk->map[run_ind - 1].npages = NPAGES_EMPTY;
#endif
run_ind -= prev_npages;
assert(chunk->map[run_ind].npages == prev_npages);
assert(chunk->map[run_ind].pos >= POS_EMPTY);
run_pages += prev_npages;
chunk->map[run_ind].npages = run_pages;
assert(chunk->map[run_ind].pos >= POS_EMPTY);
chunk->map[run_ind + run_pages - 1].npages = run_pages;
assert(chunk->map[run_ind + run_pages - 1].pos >= POS_EMPTY);
}
if (run_ind + run_pages < chunk_npages &&
chunk->map[run_ind + run_pages].pos >= POS_EMPTY) {
unsigned next_npages;
/* Coalesce with next run. */
next_npages = chunk->map[run_ind + run_pages].npages;
if (next_npages > 1 && chunk->map[run_ind + run_pages].pos ==
POS_EMPTY)
chunk->map[run_ind + run_pages].npages = NPAGES_EMPTY;
run_pages += next_npages;
assert(chunk->map[run_ind + run_pages - 1].npages ==
next_npages);
assert(chunk->map[run_ind + run_pages - 1].pos >= POS_EMPTY);
chunk->map[run_ind].npages = run_pages;
assert(chunk->map[run_ind].pos >= POS_EMPTY);
chunk->map[run_ind + run_pages - 1].npages = run_pages;
assert(chunk->map[run_ind + run_pages - 1].pos >= POS_EMPTY);
}
if (chunk->map[run_ind].npages > chunk->max_frun_npages)
chunk->max_frun_npages = chunk->map[run_ind].npages;
if (run_ind < chunk->min_frun_ind)
chunk->min_frun_ind = run_ind;
/* Deallocate chunk if it is now completely unused. */
if (chunk->pages_used == 0)
arena_chunk_dealloc(arena, chunk);
}
static arena_run_t *
arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin)
{
arena_run_t *run;
unsigned i, remainder;
/* Look for a usable run. */
if ((run = RB_MIN(arena_run_tree_s, &bin->runs)) != NULL) {
/* run is guaranteed to have available space. */
RB_REMOVE(arena_run_tree_s, &bin->runs, run);
#ifdef MALLOC_STATS
bin->stats.reruns++;
#endif
return (run);
}
/* No existing runs have any space available. */
/* Allocate a new run. */
run = arena_run_alloc(arena, bin->run_size, false);
if (run == NULL)
return (NULL);
/* Initialize run internals. */
run->bin = bin;
for (i = 0; i < bin->regs_mask_nelms; i++)
run->regs_mask[i] = UINT_MAX;
remainder = bin->nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1);
if (remainder != 0) {
/* The last element has spare bits that need to be unset. */
run->regs_mask[i] = (UINT_MAX >> ((1U << (SIZEOF_INT_2POW + 3))
- remainder));
}
run->regs_minelm = 0;
run->nfree = bin->nregs;
#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)
{
void *ret;
assert(run->magic == ARENA_RUN_MAGIC);
assert(run->nfree > 0);
ret = arena_run_reg_alloc(run, bin);
assert(ret != NULL);
run->nfree--;
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)
{
bin->runcur = arena_bin_nonfull_run_get(arena, bin);
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));
}
/*
* Calculate bin->run_size such that it meets the following constraints:
*
* *) bin->run_size >= min_run_size
* *) bin->run_size <= arena_maxclass
* *) bin->run_size <= RUN_MAX_SMALL
* *) run header overhead <= RUN_MAX_OVRHD (or header overhead relaxed).
*
* bin->nregs, bin->regs_mask_nelms, and bin->reg0_offset are
* also calculated here, since these settings are all interdependent.
*/
static size_t
arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size)
{
size_t try_run_size, good_run_size;
unsigned good_nregs, good_mask_nelms, good_reg0_offset;
unsigned try_nregs, try_mask_nelms, try_reg0_offset;
assert(min_run_size >= pagesize);
assert(min_run_size <= arena_maxclass);
assert(min_run_size <= RUN_MAX_SMALL);
/*
* Calculate known-valid settings before entering the run_size
* expansion loop, so that the first part of the loop always copies
* valid settings.
*
* The do..while loop iteratively reduces the number of regions until
* the run header and the regions no longer overlap. A closed formula
* would be quite messy, since there is an interdependency between the
* header's mask length and the number of regions.
*/
try_run_size = min_run_size;
try_nregs = ((try_run_size - sizeof(arena_run_t)) / bin->reg_size)
+ 1; /* Counter-act try_nregs-- in loop. */
do {
try_nregs--;
try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ? 1 : 0);
try_reg0_offset = try_run_size - (try_nregs * bin->reg_size);
} while (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1))
> try_reg0_offset);
/* run_size expansion loop. */
do {
/*
* Copy valid settings before trying more aggressive settings.
*/
good_run_size = try_run_size;
good_nregs = try_nregs;
good_mask_nelms = try_mask_nelms;
good_reg0_offset = try_reg0_offset;
/* Try more aggressive settings. */
try_run_size += pagesize;
try_nregs = ((try_run_size - sizeof(arena_run_t)) /
bin->reg_size) + 1; /* Counter-act try_nregs-- in loop. */
do {
try_nregs--;
try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ?
1 : 0);
try_reg0_offset = try_run_size - (try_nregs *
bin->reg_size);
} while (sizeof(arena_run_t) + (sizeof(unsigned) *
(try_mask_nelms - 1)) > try_reg0_offset);
} while (try_run_size <= arena_maxclass && try_run_size <= RUN_MAX_SMALL
&& RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX
&& (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size);
assert(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1))
<= good_reg0_offset);
assert((good_mask_nelms << (SIZEOF_INT_2POW + 3)) >= good_nregs);
/* Copy final settings. */
bin->run_size = good_run_size;
bin->nregs = good_nregs;
bin->regs_mask_nelms = good_mask_nelms;
bin->reg0_offset = good_reg0_offset;
return (good_run_size);
}
#ifdef MALLOC_BALANCE
static inline void
arena_lock_balance(arena_t *arena)
{
unsigned contention;
contention = malloc_spin_lock(&arena->lock);
if (narenas > 1) {
/*
* Calculate the exponentially averaged contention for this
* arena. Due to integer math always rounding down, this value
* decays somewhat faster then normal.
*/
arena->contention = (((uint64_t)arena->contention
* (uint64_t)((1U << BALANCE_ALPHA_INV_2POW)-1))
+ (uint64_t)contention) >> BALANCE_ALPHA_INV_2POW;
if (arena->contention >= opt_balance_threshold) {
uint32_t ind;
arena->contention = 0;
#ifdef MALLOC_STATS
arena->stats.nbalance++;
#endif
ind = PRN(balance, narenas_2pow);
if (arenas[ind] != NULL)
arenas_map = arenas[ind];
else {
malloc_spin_lock(&arenas_lock);
if (arenas[ind] != NULL)
arenas_map = arenas[ind];
else
arenas_map = arenas_extend(ind);
malloc_spin_unlock(&arenas_lock);
}
}
}
}
#endif
static void *
arena_malloc(arena_t *arena, size_t size, bool zero)
{
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((int)(size >> (TINY_MIN_2POW +
1)))];
#if (!defined(NDEBUG) || defined(MALLOC_STATS))
/*
* Bin calculation is always correct, but we may need
* to fix size for the purposes of assertions and/or
* stats accuracy.
*/
if (size < (1U << TINY_MIN_2POW))
size = (1U << 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((int)(size >> opt_small_max_2pow)) - 2)];
}
assert(size == bin->reg_size);
#ifdef MALLOC_BALANCE
arena_lock_balance(arena);
#else
malloc_spin_lock(&arena->lock);
#endif
if ((run = bin->runcur) != NULL && run->nfree > 0)
ret = arena_bin_malloc_easy(arena, bin, run);
else
ret = arena_bin_malloc_hard(arena, bin);
if (ret == NULL) {
malloc_spin_unlock(&arena->lock);
return (NULL);
}
#ifdef MALLOC_STATS
bin->stats.nrequests++;
arena->stats.nmalloc_small++;
arena->stats.allocated_small += size;
#endif
malloc_spin_unlock(&arena->lock);
if (zero == false) {
if (opt_junk)
memset(ret, 0xa5, size);
else if (opt_zero)
memset(ret, 0, size);
} else
memset(ret, 0, size);
} else {
/* Large allocation. */
size = PAGE_CEILING(size);
#ifdef MALLOC_BALANCE
arena_lock_balance(arena);
#else
malloc_spin_lock(&arena->lock);
#endif
ret = (void *)arena_run_alloc(arena, size, zero);
if (ret == NULL) {
malloc_spin_unlock(&arena->lock);
return (NULL);
}
#ifdef MALLOC_STATS
arena->stats.nmalloc_large++;
arena->stats.allocated_large += size;
#endif
malloc_spin_unlock(&arena->lock);
if (zero == false) {
if (opt_junk)
memset(ret, 0xa5, size);
else if (opt_zero)
memset(ret, 0, size);
}
}
return (ret);
}
static inline void
arena_palloc_trim(arena_t *arena, arena_chunk_t *chunk, unsigned pageind,
unsigned npages)
{
unsigned i;
assert(npages > 0);
/*
* Modifiy the map such that arena_run_dalloc() sees the run as
* separately allocated.
*/
for (i = 0; i < npages; i++) {
chunk->map[pageind + i].npages = npages;
chunk->map[pageind + i].pos = i;
}
arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)chunk + (pageind <<
pagesize_2pow)), npages << pagesize_2pow);
}
/* Only handles large allocations that require more than page alignment. */
static void *
arena_palloc(arena_t *arena, size_t alignment, size_t size, size_t alloc_size)
{
void *ret;
size_t offset;
arena_chunk_t *chunk;
unsigned pageind, i, npages;
assert((size & pagesize_mask) == 0);
assert((alignment & pagesize_mask) == 0);
npages = size >> pagesize_2pow;
#ifdef MALLOC_BALANCE
arena_lock_balance(arena);
#else
malloc_spin_lock(&arena->lock);
#endif
ret = (void *)arena_run_alloc(arena, alloc_size, false);
if (ret == NULL) {
malloc_spin_unlock(&arena->lock);
return (NULL);
}
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ret);
offset = (uintptr_t)ret & (alignment - 1);
assert((offset & pagesize_mask) == 0);
assert(offset < alloc_size);
if (offset == 0) {
pageind = (((uintptr_t)ret - (uintptr_t)chunk) >>
pagesize_2pow);
/* Update the map for the run to be kept. */
for (i = 0; i < npages; i++) {
chunk->map[pageind + i].npages = npages;
assert(chunk->map[pageind + i].pos == i);
}
/* Trim trailing space. */
arena_palloc_trim(arena, chunk, pageind + npages,
(alloc_size - size) >> pagesize_2pow);
} else {
size_t leadsize, trailsize;
leadsize = alignment - offset;
ret = (void *)((uintptr_t)ret + leadsize);
pageind = (((uintptr_t)ret - (uintptr_t)chunk) >>
pagesize_2pow);
/* Update the map for the run to be kept. */
for (i = 0; i < npages; i++) {
chunk->map[pageind + i].npages = npages;
chunk->map[pageind + i].pos = i;
}
/* Trim leading space. */
arena_palloc_trim(arena, chunk, pageind - (leadsize >>
pagesize_2pow), leadsize >> pagesize_2pow);
trailsize = alloc_size - leadsize - size;
if (trailsize != 0) {
/* Trim trailing space. */
assert(trailsize < alloc_size);
arena_palloc_trim(arena, chunk, pageind + npages,
trailsize >> pagesize_2pow);
}
}
#ifdef MALLOC_STATS
arena->stats.nmalloc_large++;
arena->stats.allocated_large += size;
#endif
malloc_spin_unlock(&arena->lock);
if (opt_junk)
memset(ret, 0xa5, size);
else if (opt_zero)
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;
arena_chunk_map_t *mapelm;
unsigned pageind;
assert(ptr != NULL);
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];
if (mapelm->pos != 0 || ptr != (void *)(((uintptr_t)chunk) + (pageind <<
pagesize_2pow))) {
arena_run_t *run;
pageind -= mapelm->pos;
run = (arena_run_t *)((uintptr_t)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((int)(pow2_ceil(size) >> (TINY_MIN_2POW + 1)))
== ffs((int)(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 {
/*
* We make no attempt to resize runs here, though it would be
* possible to do so.
*/
if (oldsize > small_max && PAGE_CEILING(size) == 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, false);
if (ret == NULL)
return (NULL);
/* Junk/zero-filling were already done by arena_malloc(). */
if (size < oldsize)
memcpy(ret, ptr, size);
else
memcpy(ret, ptr, oldsize);
idalloc(ptr);
return (ret);
IN_PLACE:
if (opt_junk && size < oldsize)
memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize - size);
else if (opt_zero && size > oldsize)
memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize);
return (ptr);
}
static inline void
arena_dalloc_small(arena_t *arena, arena_chunk_t *chunk, void *ptr,
unsigned pageind, arena_chunk_map_t *mapelm)
{
arena_run_t *run;
arena_bin_t *bin;
size_t size;
pageind -= mapelm->pos;
run = (arena_run_t *)((uintptr_t)chunk + (pageind << pagesize_2pow));
assert(run->magic == ARENA_RUN_MAGIC);
bin = run->bin;
size = bin->reg_size;
if (opt_junk)
memset(ptr, 0x5a, size);
arena_run_reg_dalloc(run, bin, ptr, size);
run->nfree++;
if (run->nfree == bin->nregs) {
/* Deallocate run. */
if (run == bin->runcur)
bin->runcur = NULL;
else if (bin->nregs != 1) {
/*
* This block's conditional is necessary because if the
* run only contains one region, then it never gets
* inserted into the non-full runs tree.
*/
RB_REMOVE(arena_run_tree_s, &bin->runs, run);
}
#ifdef MALLOC_DEBUG
run->magic = 0;
#endif
arena_run_dalloc(arena, run, bin->run_size);
#ifdef MALLOC_STATS
bin->stats.curruns--;
#endif
} else if (run->nfree == 1 && run != bin->runcur) {
/*
* Make sure that bin->runcur always refers to the lowest
* non-full run, if one exists.
*/
if (bin->runcur == NULL)
bin->runcur = run;
else if ((uintptr_t)run < (uintptr_t)bin->runcur) {
/* Switch runcur. */
if (bin->runcur->nfree > 0) {
/* Insert runcur. */
RB_INSERT(arena_run_tree_s, &bin->runs,
bin->runcur);
}
bin->runcur = run;
} else
RB_INSERT(arena_run_tree_s, &bin->runs, run);
}
#ifdef MALLOC_STATS
arena->stats.allocated_small -= size;
arena->stats.ndalloc_small++;
#endif
}
#ifdef MALLOC_LAZY_FREE
static inline void
arena_dalloc_lazy(arena_t *arena, arena_chunk_t *chunk, void *ptr,
unsigned pageind, arena_chunk_map_t *mapelm)
{
void **free_cache = arena->free_cache;
unsigned i, slot;
if (!__isthreaded || opt_lazy_free_2pow < 0) {
malloc_spin_lock(&arena->lock);
arena_dalloc_small(arena, chunk, ptr, pageind, mapelm);
malloc_spin_unlock(&arena->lock);
return;
}
for (i = 0; i < LAZY_FREE_NPROBES; i++) {
slot = PRN(lazy_free, opt_lazy_free_2pow);
if (atomic_cmpset_ptr((uintptr_t *)&free_cache[slot],
(uintptr_t)NULL, (uintptr_t)ptr)) {
return;
}
}
malloc_spin_lock(&arena->lock);
arena_dalloc_small(arena, chunk, ptr, pageind, mapelm);
/*
* Check whether another thread already cleared the cache. It is
* possible that another thread cleared the cache *and* this slot was
* already refilled, which could result in a mostly fruitless cache
* sweep, but such a sequence of events causes no correctness issues.
*/
if ((ptr = (void *)atomic_readandclear_ptr(
(uintptr_t *)&free_cache[slot]))
!= NULL) {
unsigned lazy_free_mask;
/*
* Clear the cache, since we failed to find a slot. It is
* possible that other threads will continue to insert objects
* into the cache while this one sweeps, but that is okay,
* since on average the cache is still swept with the same
* frequency.
*/
/* Handle pointer at current slot. */
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >>
pagesize_2pow);
mapelm = &chunk->map[pageind];
arena_dalloc_small(arena, chunk, ptr, pageind, mapelm);
/* Sweep remainder of slots. */
lazy_free_mask = (1U << opt_lazy_free_2pow) - 1;
for (i = (slot + 1) & lazy_free_mask;
i != slot;
i = (i + 1) & lazy_free_mask) {
ptr = (void *)atomic_readandclear_ptr(
(uintptr_t *)&free_cache[i]);
if (ptr != NULL) {
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk)
>> pagesize_2pow);
mapelm = &chunk->map[pageind];
arena_dalloc_small(arena, chunk, ptr, pageind,
mapelm);
}
}
}
malloc_spin_unlock(&arena->lock);
}
#endif
static void
arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
{
unsigned pageind;
arena_chunk_map_t *mapelm;
assert(arena != NULL);
assert(arena->magic == ARENA_MAGIC);
assert(chunk->arena == arena);
assert(ptr != NULL);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
mapelm = &chunk->map[pageind];
if (mapelm->pos != 0 || ptr != (void *)(((uintptr_t)chunk) + (pageind <<
pagesize_2pow))) {
/* Small allocation. */
#ifdef MALLOC_LAZY_FREE
arena_dalloc_lazy(arena, chunk, ptr, pageind, mapelm);
#else
malloc_spin_lock(&arena->lock);
arena_dalloc_small(arena, chunk, ptr, pageind, mapelm);
malloc_spin_unlock(&arena->lock);
#endif
} else {
size_t size;
/* Large allocation. */
size = mapelm->npages << pagesize_2pow;
assert((((uintptr_t)ptr) & pagesize_mask) == 0);
if (opt_junk)
memset(ptr, 0x5a, size);
malloc_spin_lock(&arena->lock);
arena_run_dalloc(arena, (arena_run_t *)ptr, size);
#ifdef MALLOC_STATS
arena->stats.allocated_large -= size;
arena->stats.ndalloc_large++;
#endif
malloc_spin_unlock(&arena->lock);
}
}
static bool
arena_new(arena_t *arena)
{
unsigned i;
arena_bin_t *bin;
size_t pow2_size, prev_run_size;
if (malloc_spin_init(&arena->lock))
return (true);
#ifdef MALLOC_STATS
memset(&arena->stats, 0, sizeof(arena_stats_t));
#endif
/* Initialize chunks. */
RB_INIT(&arena->chunks);
arena->spare = NULL;
#ifdef MALLOC_BALANCE
arena->contention = 0;
#endif
#ifdef MALLOC_LAZY_FREE
if (opt_lazy_free_2pow >= 0) {
arena->free_cache = (void **) base_alloc(sizeof(void *)
* (1U << opt_lazy_free_2pow));
if (arena->free_cache == NULL)
return (true);
memset(arena->free_cache, 0, sizeof(void *)
* (1U << opt_lazy_free_2pow));
} else
arena->free_cache = NULL;
#endif
/* Initialize bins. */
prev_run_size = pagesize;
/* (2^n)-spaced tiny bins. */
for (i = 0; i < ntbins; i++) {
bin = &arena->bins[i];
bin->runcur = NULL;
RB_INIT(&bin->runs);
bin->reg_size = (1U << (TINY_MIN_2POW + i));
prev_run_size = arena_bin_run_size_calc(bin, prev_run_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;
RB_INIT(&bin->runs);
bin->reg_size = quantum * (i - ntbins + 1);
pow2_size = pow2_ceil(quantum * (i - ntbins + 1));
prev_run_size = arena_bin_run_size_calc(bin, prev_run_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;
RB_INIT(&bin->runs);
bin->reg_size = (small_max << (i - (ntbins + nqbins) + 1));
prev_run_size = arena_bin_run_size_calc(bin, prev_run_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_message(_getprogname(),
": (malloc) Error initializing arena\n", "", "");
if (opt_abort)
abort();
return (arenas[0]);
}
/*
* End arena.
*/
/******************************************************************************/
/*
* Begin general internal functions.
*/
static void *
huge_malloc(size_t size, bool zero)
{
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 huge. */
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 (zero == false) {
if (opt_junk)
memset(ret, 0xa5, csize);
else if (opt_zero)
memset(ret, 0, csize);
}
return (ret);
}
/* Only handles large allocations that require more than chunk alignment. */
static void *
huge_palloc(size_t alignment, size_t size)
{
void *ret;
size_t alloc_size, chunk_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.
*/
assert(alignment >= chunksize);
chunk_size = CHUNK_CEILING(size);
if (size >= alignment)
alloc_size = chunk_size + alignment - chunksize;
else
alloc_size = (alignment << 1) - chunksize;
/* 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 & chunksize_mask) == 0);
assert(offset < alloc_size);
if (offset == 0) {
/* Trim trailing space. */
chunk_dealloc((void *)((uintptr_t)ret + chunk_size), alloc_size
- chunk_size);
} else {
size_t trailsize;
/* Trim leading space. */
chunk_dealloc(ret, alignment - offset);
ret = (void *)((uintptr_t)ret + (alignment - offset));
trailsize = alloc_size - (alignment - offset) - chunk_size;
if (trailsize != 0) {
/* Trim trailing space. */
assert(trailsize < alloc_size);
chunk_dealloc((void *)((uintptr_t)ret + chunk_size),
trailsize);
}
}
/* Insert node into huge. */
node->chunk = ret;
node->size = chunk_size;
malloc_mutex_lock(&chunks_mtx);
RB_INSERT(chunk_tree_s, &huge, node);
#ifdef MALLOC_STATS
huge_nmalloc++;
huge_allocated += chunk_size;
#endif
malloc_mutex_unlock(&chunks_mtx);
if (opt_junk)
memset(ret, 0xa5, chunk_size);
else if (opt_zero)
memset(ret, 0, chunk_size);
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)) {
if (opt_junk && size < oldsize) {
memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize
- size);
} else if (opt_zero && size > oldsize) {
memset((void *)((uintptr_t)ptr + oldsize), 0, size
- 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, false);
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
huge_ndalloc++;
huge_allocated -= node->size;
#endif
malloc_mutex_unlock(&chunks_mtx);
/* Unmap chunk. */
#ifdef MALLOC_DSS
if (opt_dss && 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, false);
else
ret = huge_malloc(size, false);
return (ret);
}
static void *
ipalloc(size_t alignment, size_t size)
{
void *ret;
size_t ceil_size;
/*
* Round size up to the nearest multiple of alignment.
*
* This done, we can take advantage of the fact that for each small
* size class, every object is aligned at the smallest power of two
* that is non-zero in the base two representation of the size. For
* example:
*
* Size | Base 2 | Minimum alignment
* -----+----------+------------------
* 96 | 1100000 | 32
* 144 | 10100000 | 32
* 192 | 11000000 | 64
*
* Depending on runtime settings, it is possible that arena_malloc()
* will further round up to a power of two, but that never causes
* correctness issues.
*/
ceil_size = (size + (alignment - 1)) & (-alignment);
/*
* (ceil_size < size) protects against the combination of maximal
* alignment and size greater than maximal alignment.
*/
if (ceil_size < size) {
/* size_t overflow. */
return (NULL);
}
if (ceil_size <= pagesize || (alignment <= pagesize
&& ceil_size <= arena_maxclass))
ret = arena_malloc(choose_arena(), ceil_size, false);
else {
size_t run_size;
/*
* We can't achieve sub-page alignment, so round up alignment
* permanently; it makes later calculations simpler.
*/
alignment = PAGE_CEILING(alignment);
ceil_size = PAGE_CEILING(size);
/*
* (ceil_size < size) protects against very large sizes within
* pagesize of SIZE_T_MAX.
*
* (ceil_size + alignment < ceil_size) protects against the
* combination of maximal alignment and ceil_size large enough
* to cause overflow. This is similar to the first overflow
* check above, but it needs to be repeated due to the new
* ceil_size value, which may now be *equal* to maximal
* alignment, whereas before we only detected overflow if the
* original size was *greater* than maximal alignment.
*/
if (ceil_size < size || ceil_size + alignment < ceil_size) {
/* size_t overflow. */
return (NULL);
}
/*
* Calculate the size of the over-size run that arena_palloc()
* would need to allocate in order to guarantee the alignment.
*/
if (ceil_size >= alignment)
run_size = ceil_size + alignment - pagesize;
else {
/*
* It is possible that (alignment << 1) will cause
* overflow, but it doesn't matter because we also
* subtract pagesize, which in the case of overflow
* leaves us with a very large run_size. That causes
* the first conditional below to fail, which means
* that the bogus run_size value never gets used for
* anything important.
*/
run_size = (alignment << 1) - pagesize;
}
if (run_size <= arena_maxclass) {
ret = arena_palloc(choose_arena(), alignment, ceil_size,
run_size);
} else if (alignment <= chunksize)
ret = huge_malloc(ceil_size, false);
else
ret = huge_palloc(alignment, ceil_size);
}
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, true);
else
ret = huge_malloc(size, true);
return (ret);
}
static size_t
isalloc(const void *ptr)
{
size_t ret;
arena_chunk_t *chunk;
assert(ptr != NULL);
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 = __DECONST(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(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);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
/* Region. */
arena_dalloc(chunk->arena, chunk, ptr);
} else
huge_dalloc(ptr);
}
static void
malloc_print_stats(void)
{
if (opt_print_stats) {
char s[UMAX2S_BUFSIZE];
_malloc_message("___ Begin malloc statistics ___\n", "", "",
"");
_malloc_message("Assertions ",
#ifdef NDEBUG
"disabled",
#else
"enabled",
#endif
"\n", "");
_malloc_message("Boolean MALLOC_OPTIONS: ",
opt_abort ? "A" : "a", "", "");
#ifdef MALLOC_DSS
_malloc_message(opt_dss ? "D" : "d", "", "", "");
#endif
_malloc_message(opt_hint ? "H" : "h",
opt_junk ? "J" : "j", "", "");
#ifdef MALLOC_DSS
_malloc_message(opt_mmap ? "M" : "m", "", "", "");
#endif
_malloc_message(opt_utrace ? "PU" : "Pu",
opt_sysv ? "V" : "v",
opt_xmalloc ? "X" : "x",
opt_zero ? "Z\n" : "z\n");
_malloc_message("CPUs: ", umax2s(ncpus, s), "\n", "");
_malloc_message("Max arenas: ", umax2s(narenas, s), "\n", "");
#ifdef MALLOC_LAZY_FREE
if (opt_lazy_free_2pow >= 0) {
_malloc_message("Lazy free slots: ",
umax2s(1U << opt_lazy_free_2pow, s), "\n", "");
} else
_malloc_message("Lazy free slots: 0\n", "", "", "");
#endif
#ifdef MALLOC_BALANCE
_malloc_message("Arena balance threshold: ",
umax2s(opt_balance_threshold, s), "\n", "");
#endif
_malloc_message("Pointer size: ", umax2s(sizeof(void *), s),
"\n", "");
_malloc_message("Quantum size: ", umax2s(quantum, s), "\n", "");
_malloc_message("Max small size: ", umax2s(small_max, s), "\n",
"");
_malloc_message("Chunk size: ", umax2s(chunksize, s), "", "");
_malloc_message(" (2^", umax2s(opt_chunk_2pow, s), ")\n", "");
#ifdef MALLOC_STATS
{
size_t allocated, mapped;
#ifdef MALLOC_BALANCE
uint64_t nbalance = 0;
#endif
unsigned i;
arena_t *arena;
/* Calculate and print allocated/mapped stats. */
/* arenas. */
for (i = 0, allocated = 0; i < narenas; i++) {
if (arenas[i] != NULL) {
malloc_spin_lock(&arenas[i]->lock);
allocated +=
arenas[i]->stats.allocated_small;
allocated +=
arenas[i]->stats.allocated_large;
#ifdef MALLOC_BALANCE
nbalance += arenas[i]->stats.nbalance;
#endif
malloc_spin_unlock(&arenas[i]->lock);
}
}
/* huge/base. */
malloc_mutex_lock(&chunks_mtx);
allocated += huge_allocated;
mapped = stats_chunks.curchunks * chunksize;
malloc_mutex_unlock(&chunks_mtx);
malloc_mutex_lock(&base_mtx);
mapped += base_mapped;
malloc_mutex_unlock(&base_mtx);
malloc_printf("Allocated: %zu, mapped: %zu\n",
allocated, mapped);
#ifdef MALLOC_BALANCE
malloc_printf("Arena balance reassignments: %llu\n",
nbalance);
#endif
/* Print chunk stats. */
{
chunk_stats_t chunks_stats;
malloc_mutex_lock(&chunks_mtx);
chunks_stats = stats_chunks;
malloc_mutex_unlock(&chunks_mtx);
malloc_printf("chunks: nchunks "
"highchunks curchunks\n");
malloc_printf(" %13llu%13lu%13lu\n",
chunks_stats.nchunks,
chunks_stats.highchunks,
chunks_stats.curchunks);
}
/* Print chunk stats. */
malloc_printf(
"huge: nmalloc ndalloc allocated\n");
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]:\n", i);
malloc_spin_lock(&arena->lock);
stats_print(arena);
malloc_spin_unlock(&arena->lock);
}
}
}
#endif /* #ifdef MALLOC_STATS */
_malloc_message("--- 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;
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;
}
}
#ifdef MALLOC_LAZY_FREE
if (ncpus == 1)
opt_lazy_free_2pow = -1;
#endif
/* 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_mask and pagesize_2pow.
*/
assert(((result - 1) & result) == 0);
pagesize_mask = result - 1;
pagesize_2pow = ffs((int)result) - 1;
}
for (i = 0; i < 3; i++) {
unsigned j;
/* 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++) {
unsigned k, nreps;
bool nseen;
/* Parse repetition count, if any. */
for (nreps = 0, nseen = false;; j++, nseen = true) {
switch (opts[j]) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
case '8': case '9':
nreps *= 10;
nreps += opts[j] - '0';
break;
default:
goto OUT;
}
}
OUT:
if (nseen == false)
nreps = 1;
for (k = 0; k < nreps; k++) {
switch (opts[j]) {
case 'a':
opt_abort = false;
break;
case 'A':
opt_abort = true;
break;
case 'b':
#ifdef MALLOC_BALANCE
opt_balance_threshold >>= 1;
#endif
break;
case 'B':
#ifdef MALLOC_BALANCE
if (opt_balance_threshold == 0)
opt_balance_threshold = 1;
else if ((opt_balance_threshold << 1)
> opt_balance_threshold)
opt_balance_threshold <<= 1;
#endif
break;
case 'd':
#ifdef MALLOC_DSS
opt_dss = false;
#endif
break;
case 'D':
#ifdef MALLOC_DSS
opt_dss = true;
#endif
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':
/*
* Chunks always require at least one
* header page, so chunks can never be
* smaller than two pages.
*/
if (opt_chunk_2pow > pagesize_2pow + 1)
opt_chunk_2pow--;
break;
case 'K':
/*
* There must be fewer pages in a chunk
* than can be recorded by the pos
* field of arena_chunk_map_t, in order
* to make POS_EMPTY/POS_FREE special.
*/
if (opt_chunk_2pow - pagesize_2pow
< (sizeof(uint32_t) << 3) - 1)
opt_chunk_2pow++;
break;
case 'l':
#ifdef MALLOC_LAZY_FREE
if (opt_lazy_free_2pow >= 0)
opt_lazy_free_2pow--;
#endif
break;
case 'L':
#ifdef MALLOC_LAZY_FREE
if (ncpus > 1)
opt_lazy_free_2pow++;
#endif
break;
case 'm':
#ifdef MALLOC_DSS
opt_mmap = false;
#endif
break;
case 'M':
#ifdef MALLOC_DSS
opt_mmap = true;
#endif
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: {
char cbuf[2];
cbuf[0] = opts[j];
cbuf[1] = '\0';
_malloc_message(_getprogname(),
": (malloc) Unsupported character "
"in malloc options: '", cbuf,
"'\n");
}
}
}
}
}
#ifdef MALLOC_DSS
/* Make sure that there is some method for acquiring memory. */
if (opt_dss == false && opt_mmap == false)
opt_mmap = true;
#endif
/* 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 = (1U << opt_small_max_2pow);
/* Set bin-related variables. */
bin_maxclass = (pagesize >> 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 = (1U << 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. */
chunksize = (1LU << opt_chunk_2pow);
chunksize_mask = chunksize - 1;
chunk_npages = (chunksize >> pagesize_2pow);
{
unsigned header_size;
header_size = sizeof(arena_chunk_t) + (sizeof(arena_chunk_map_t)
* (chunk_npages - 1));
arena_chunk_header_npages = (header_size >> pagesize_2pow);
if ((header_size & pagesize_mask) != 0)
arena_chunk_header_npages++;
}
arena_maxclass = chunksize - (arena_chunk_header_npages <<
pagesize_2pow);
#ifdef MALLOC_LAZY_FREE
/*
* Make sure that allocating the free_cache does not exceed the limits
* of what base_alloc() can handle.
*/
while ((sizeof(void *) << opt_lazy_free_2pow) > chunksize)
opt_lazy_free_2pow--;
#endif
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(chunksize >= pagesize);
assert(quantum * 4 <= chunksize);
/* Initialize chunks data. */
malloc_mutex_init(&chunks_mtx);
RB_INIT(&huge);
#ifdef MALLOC_DSS
malloc_mutex_init(&dss_mtx);
dss_base = sbrk(0);
dss_prev = dss_base;
dss_max = dss_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_mapped = 0;
#endif
#ifdef MALLOC_DSS
/*
* Allocate a base chunk here, since it doesn't actually have to be
* chunk-aligned. Doing this before allocating any other chunks allows
* the use of space that would otherwise be wasted.
*/
if (opt_dss)
base_pages_alloc(0);
#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_alloc() can
* handle.
*/
if (narenas * sizeof(arena_t *) > chunksize)
narenas = chunksize / 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 MALLOC_BALANCE
assert(narenas != 0);
for (narenas_2pow = 0;
(narenas >> (narenas_2pow + 1)) != 0;
narenas_2pow++);
#endif
#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 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
# ifndef MALLOC_BALANCE
next_arena = 0;
# endif
#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
* choose_arena_hard().
*/
arenas_extend(0);
if (arenas[0] == NULL) {
malloc_mutex_unlock(&init_lock);
return (true);
}
#ifndef NO_TLS
/*
* Assign the initial arena to the initial thread, in order to avoid
* spurious creation of an extra arena if the application switches to
* threaded mode.
*/
arenas_map = arenas[0];
#endif
/*
* Seed here for the initial thread, since choose_arena_hard() is only
* called for other threads. The seed values don't really matter.
*/
#ifdef MALLOC_LAZY_FREE
SPRN(lazy_free, 42);
#endif
#ifdef MALLOC_BALANCE
SPRN(balance, 42);
#endif
malloc_spin_init(&arenas_lock);
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)
size = 1;
else {
ret = NULL;
goto RETURN;
}
}
ret = imalloc(size);
RETURN:
if (ret == NULL) {
if (opt_xmalloc) {
_malloc_message(_getprogname(),
": (malloc) Error in malloc(): out of memory\n", "",
"");
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_message(_getprogname(),
": (malloc) Error in posix_memalign(): "
"invalid alignment\n", "", "");
abort();
}
result = NULL;
ret = EINVAL;
goto RETURN;
}
result = ipalloc(alignment, size);
}
if (result == NULL) {
if (opt_xmalloc) {
_malloc_message(_getprogname(),
": (malloc) Error in posix_memalign(): out of memory\n",
"", "");
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()) {
num_size = 0;
ret = NULL;
goto RETURN;
}
num_size = num * size;
if (num_size == 0) {
if ((opt_sysv == false) && ((num == 0) || (size == 0)))
num_size = 1;
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_message(_getprogname(),
": (malloc) Error in calloc(): out of memory\n", "",
"");
abort();
}
errno = ENOMEM;
}
UTRACE(0, num_size, ret);
return (ret);
}
void *
realloc(void *ptr, size_t size)
{
void *ret;
if (size == 0) {
if (opt_sysv == false)
size = 1;
else {
if (ptr != NULL)
idalloc(ptr);
ret = NULL;
goto RETURN;
}
}
if (ptr != NULL) {
assert(malloc_initialized);
ret = iralloc(ptr, size);
if (ret == NULL) {
if (opt_xmalloc) {
_malloc_message(_getprogname(),
": (malloc) Error in realloc(): out of "
"memory\n", "", "");
abort();
}
errno = ENOMEM;
}
} else {
if (malloc_init())
ret = NULL;
else
ret = imalloc(size);
if (ret == NULL) {
if (opt_xmalloc) {
_malloc_message(_getprogname(),
": (malloc) Error in realloc(): out of "
"memory\n", "", "");
abort();
}
errno = ENOMEM;
}
}
RETURN:
UTRACE(ptr, size, ret);
return (ret);
}
void
free(void *ptr)
{
UTRACE(ptr, 0, 0);
if (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);
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_spin_lock(&arenas_lock);
for (i = 0; i < narenas; i++) {
if (arenas[i] != NULL)
malloc_spin_lock(&arenas[i]->lock);
}
malloc_spin_unlock(&arenas_lock);
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_spin_lock(&arenas_lock);
for (i = 0; i < narenas; i++) {
if (arenas[i] != NULL)
malloc_spin_unlock(&arenas[i]->lock);
}
malloc_spin_unlock(&arenas_lock);
}
/*
* End library-private functions.
*/
/******************************************************************************/
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