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Diffstat (limited to 'lib/libc/stdlib/malloc.c')
| -rw-r--r-- | lib/libc/stdlib/malloc.c | 4578 |
1 files changed, 4578 insertions, 0 deletions
diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c new file mode 100644 index 0000000..79ceb4b --- /dev/null +++ b/lib/libc/stdlib/malloc.c @@ -0,0 +1,4578 @@ +/*- + * 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) + goto RETURN; + } + + if (opt_mmap) +#endif + chunk_dealloc_mmap(chunk, size); + +#ifdef MALLOC_DSS +RETURN: +#endif +#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. + */ +/******************************************************************************/ |
