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e3085308be
freebsd-skq/lib/libc/stdlib/malloc.c
Jason Evans e3085308be Check for integer overflow before calling sbrk(2), since it uses a 
signed increment argument, but the size is an unsigned integer.
2008-04-29 01:32:42 +00:00

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/*-
* Copyright (C) 2006-2008 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 on a 32-bit system, 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 |
* | | ... |
* | | 1004 kB |
* | | 1008 kB |
* | | 1012 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_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/uio.h>
#include <sys/ktrace.h> /* Must come after several other sys/ includes. */
#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>
#include "rb.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
#endif
/*
* Size and alignment of memory chunks that are allocated by the OS's virtual
* memory system.
*/
#define CHUNK_2POW_DEFAULT 20
/* Maximum number of dirty pages per arena. */
#define DIRTY_MAX_DEFAULT (1U << 9)
/*
* 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. Note
* that small runs must be small enough that page offsets can fit within the
* CHUNK_MAP_POS_MASK bits.
*/
#define RUN_MAX_SMALL_2POW 15
#define RUN_MAX_SMALL (1U << RUN_MAX_SMALL_2POW)
/*
* 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;
/*
* Total number of purge sweeps, total number of madvise calls made,
* and total pages purged in order to keep dirty unused memory under
* control.
*/
uint64_t npurge;
uint64_t nmadvise;
uint64_t purged;
/* 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 */
/******************************************************************************/
/*
* Extent data structures.
*/
/* Tree of extents. */
typedef struct extent_node_s extent_node_t;
struct extent_node_s {
/* Linkage for the size/address-ordered tree. */
rb_node(extent_node_t) link_szad;
/* Linkage for the address-ordered tree. */
rb_node(extent_node_t) link_ad;
/* Pointer to the extent that this tree node is responsible for. */
void *addr;
/* Total region size. */
size_t size;
};
typedef rb_tree(extent_node_t) extent_tree_t;
/******************************************************************************/
/*
* Arena data structures.
*/
typedef struct arena_s arena_t;
typedef struct arena_bin_s arena_bin_t;
/*
* Each map element contains several flags, plus page position for runs that
* service small allocations.
*/
typedef uint8_t arena_chunk_map_t;
#define CHUNK_MAP_UNTOUCHED 0x80U
#define CHUNK_MAP_DIRTY 0x40U
#define CHUNK_MAP_LARGE 0x20U
#define CHUNK_MAP_POS_MASK 0x1fU
/* 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_node(arena_chunk_t) link;
/*
* Number of pages in use. This is maintained in order to make
* detection of empty chunks fast.
*/
size_t pages_used;
/* Number of dirty pages. */
size_t ndirty;
/*
* Tree of extent nodes that are embedded in the arena chunk header
* page(s). These nodes are used by arena_chunk_node_alloc().
*/
extent_tree_t nodes;
extent_node_t *nodes_past;
/*
* 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 rb_tree(arena_chunk_t) arena_chunk_tree_t;
typedef struct arena_run_s arena_run_t;
struct arena_run_s {
/* Linkage for run trees. */
rb_node(arena_run_t) link;
#ifdef MALLOC_DEBUG
uint32_t magic;
# define ARENA_RUN_MAGIC 0x384adf93
#endif
/* Bin this run is associated with. */
arena_bin_t *bin;
/* 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 rb_tree(arena_run_t) arena_run_tree_t;
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. The spare is left in the arena's chunk tree
* until it is deleted.
*
* There is one spare chunk per arena, rather than one spare total, in
* order to avoid interactions between multiple threads that could make
* a single spare inadequate.
*/
arena_chunk_t *spare;
/*
* Current count of pages within unused runs that are potentially
* dirty, and for which madvise(... MADV_FREE) has not been called. By
* tracking this, we can institute a limit on how much dirty unused
* memory is mapped for each arena.
*/
size_t ndirty;
/*
* Trees of this arena's available runs. Two trees are maintained
* using one set of nodes, since one is needed for first-best-fit run
* allocation, and the other is needed for coalescing.
*/
extent_tree_t runs_avail_szad;
extent_tree_t runs_avail_ad;
/* Tree of this arena's allocated (in-use) runs. */
extent_tree_t runs_alloced_ad;
#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
/*
* 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 size_t chunk_npages;
static size_t arena_chunk_header_npages;
static size_t arena_maxclass; /* Max size class for arenas. */
/********/
/*
* Chunks.
*/
/* Protects chunk-related data structures. */
static malloc_mutex_t huge_mtx;
/* Tree of chunks that are stand-alone huge allocations. */
static extent_tree_t huge;
#ifdef MALLOC_DSS
/*
* Protects sbrk() calls. This avoids malloc races among threads, though it
* does not protect against races with threads that call sbrk() directly.
*/
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;
/*
* Trees of chunks that were previously allocated (trees differ only in node
* ordering). These are used when allocating chunks, in an attempt to re-use
* address space. Depending on function, different tree orderings are needed,
* which is why there are two trees with the same contents.
*/
static extent_tree_t dss_chunks_szad;
static extent_tree_t dss_chunks_ad;
#endif
#ifdef MALLOC_STATS
/* Huge allocation statistics. */
static uint64_t huge_nmalloc;
static uint64_t huge_ndalloc;
static size_t huge_allocated;
#endif
/****************************/
/*
* 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 extent_node_t *base_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 = true;
#endif
static size_t opt_dirty_max = DIRTY_MAX_DEFAULT;
#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; \
ut.p = (a); \
ut.s = (b); \
ut.r = (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);
#ifdef MALLOC_DSS
static bool base_pages_alloc_dss(size_t minsize);
#endif
static bool base_pages_alloc_mmap(size_t minsize);
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 extent_node_t *base_node_alloc(void);
static void base_node_dealloc(extent_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);
#ifdef MALLOC_DSS
static void *chunk_alloc_dss(size_t size);
static void *chunk_recycle_dss(size_t size, bool zero);
#endif
static void *chunk_alloc_mmap(size_t size);
static void *chunk_alloc(size_t size, bool zero);
#ifdef MALLOC_DSS
static extent_node_t *chunk_dealloc_dss_record(void *chunk, size_t size);
static bool chunk_dealloc_dss(void *chunk, size_t size);
#endif
static void chunk_dealloc_mmap(void *chunk, size_t size);
static void chunk_dealloc(void *chunk, size_t size);
#ifndef NO_TLS
static arena_t *choose_arena_hard(void);
#endif
static extent_node_t *arena_chunk_node_alloc(arena_chunk_t *chunk);
static void arena_chunk_node_dealloc(arena_chunk_t *chunk,
extent_node_t *node);
static void arena_run_split(arena_t *arena, arena_run_t *run, size_t size,
bool small, 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 small,
bool zero);
static void arena_purge(arena_t *arena);
static void arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty);
static void arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk,
extent_node_t *nodeB, arena_run_t *run, size_t oldsize, size_t newsize);
static void arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk,
extent_node_t *nodeA, arena_run_t *run, size_t oldsize, size_t newsize,
bool dirty);
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);
#ifdef MALLOC_BALANCE
static void arena_lock_balance_hard(arena_t *arena);
#endif
static void *arena_malloc_large(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_dalloc_large(arena_t *arena, arena_chunk_t *chunk,
void *ptr);
static void arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk,
void *ptr, size_t size, size_t oldsize);
static bool arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk,
void *ptr, size_t size, size_t oldsize);
static bool arena_ralloc_large(void *ptr, size_t size, size_t oldsize);
static void *arena_ralloc(void *ptr, size_t size, size_t oldsize);
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 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);
}
#ifdef 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
#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 bool
base_pages_alloc_dss(size_t minsize)
{
/*
* Do special DSS allocation here, since base allocations don't need to
* be chunk-aligned.
*/
malloc_mutex_lock(&dss_mtx);
if (dss_prev != (void *)-1) {
intptr_t incr;
size_t csize = CHUNK_CEILING(minsize);
do {
/* Get the current end of the DSS. */
dss_max = sbrk(0);
/*
* Calculate how much padding is necessary to
* chunk-align the end of the DSS. Don't worry about
* dss_max not being chunk-aligned though.
*/
incr = (intptr_t)chunksize
- (intptr_t)CHUNK_ADDR2OFFSET(dss_max);
assert(incr >= 0);
if ((size_t)incr < minsize)
incr += csize;
dss_prev = sbrk(incr);
if (dss_prev == dss_max) {
/* Success. */
dss_max = (void *)((intptr_t)dss_prev + incr);
base_pages = dss_prev;
base_next_addr = base_pages;
base_past_addr = dss_max;
#ifdef MALLOC_STATS
base_mapped += incr;
#endif
malloc_mutex_unlock(&dss_mtx);
return (false);
}
} while (dss_prev != (void *)-1);
}
malloc_mutex_unlock(&dss_mtx);
return (true);
}
#endif
static 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))
return (NULL);
}
/* Allocate. */
ret = base_next_addr;
base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
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 extent_node_t *
base_node_alloc(void)
{
extent_node_t *ret;
malloc_mutex_lock(&base_mtx);
if (base_nodes != NULL) {
ret = base_nodes;
base_nodes = *(extent_node_t **)ret;
malloc_mutex_unlock(&base_mtx);
} else {
malloc_mutex_unlock(&base_mtx);
ret = (extent_node_t *)base_alloc(sizeof(extent_node_t));
}
return (ret);
}
static void
base_node_dealloc(extent_node_t *node)
{
malloc_mutex_lock(&base_mtx);
*(extent_node_t **)node = base_nodes;
base_nodes = node;
malloc_mutex_unlock(&base_mtx);
}
/******************************************************************************/
#ifdef MALLOC_STATS
static void
stats_print(arena_t *arena)
{
unsigned i, gap_start;
malloc_printf("dirty: %zu page%s dirty, %llu sweep%s,"
" %llu madvise%s, %llu page%s purged\n",
arena->ndirty, arena->ndirty == 1 ? "" : "s",
arena->stats.npurge, arena->stats.npurge == 1 ? "" : "s",
arena->stats.nmadvise, arena->stats.nmadvise == 1 ? "" : "s",
arena->stats.purged, arena->stats.purged == 1 ? "" : "s");
malloc_printf(" allocated nmalloc ndalloc\n");
malloc_printf("small: %12zu %12llu %12llu\n",
arena->stats.allocated_small, arena->stats.nmalloc_small,
arena->stats.ndalloc_small);
malloc_printf("large: %12zu %12llu %12llu\n",
arena->stats.allocated_large, arena->stats.nmalloc_large,
arena->stats.ndalloc_large);
malloc_printf("total: %12zu %12llu %12llu\n",
arena->stats.allocated_small + arena->stats.allocated_large,
arena->stats.nmalloc_small + arena->stats.nmalloc_large,
arena->stats.ndalloc_small + arena->stats.ndalloc_large);
malloc_printf("mapped: %12zu\n", arena->stats.mapped);
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 extent tree code.
*/
static inline int
extent_szad_comp(extent_node_t *a, extent_node_t *b)
{
int ret;
size_t a_size = a->size;
size_t b_size = b->size;
ret = (a_size > b_size) - (a_size < b_size);
if (ret == 0) {
uintptr_t a_addr = (uintptr_t)a->addr;
uintptr_t b_addr = (uintptr_t)b->addr;
ret = (a_addr > b_addr) - (a_addr < b_addr);
}
return (ret);
}
/* Wrap large red-black tree macros in functions. */
static void
extent_tree_szad_insert(extent_tree_t *tree, extent_node_t *extent)
{
rb_insert(extent_node_t, link_szad, extent_szad_comp, tree, extent);
}
static void
extent_tree_szad_remove(extent_tree_t *tree, extent_node_t *extent)
{
rb_remove(extent_node_t, link_szad, extent_szad_comp, tree, extent);
}
static inline int
extent_ad_comp(extent_node_t *a, extent_node_t *b)
{
uintptr_t a_addr = (uintptr_t)a->addr;
uintptr_t b_addr = (uintptr_t)b->addr;
return ((a_addr > b_addr) - (a_addr < b_addr));
}
/* Wrap large red-black tree macros in functions. */
static void
extent_tree_ad_insert(extent_tree_t *tree, extent_node_t *extent)
{
rb_insert(extent_node_t, link_ad, extent_ad_comp, tree, extent);
}
static void
extent_tree_ad_remove(extent_tree_t *tree, extent_node_t *extent)
{
rb_remove(extent_node_t, link_ad, extent_ad_comp, tree, extent);
}
/*
* End extent tree code.
*/
/******************************************************************************/
/*
* Begin chunk management functions.
*/
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 void *
chunk_alloc_dss(size_t size)
{
/*
* sbrk() uses a signed increment argument, so take care not to
* interpret a huge allocation request as a negative increment.
*/
if ((intptr_t)size < 0)
return (NULL);
malloc_mutex_lock(&dss_mtx);
if (dss_prev != (void *)-1) {
intptr_t incr;
/*
* The loop is necessary to recover from races with other
* threads that are using the DSS for something other than
* malloc.
*/
do {
void *ret;
/* Get the current end of the DSS. */
dss_max = 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_max);
if (incr == (intptr_t)size)
ret = dss_max;
else {
ret = (void *)((intptr_t)dss_max + incr);
incr += size;
}
dss_prev = sbrk(incr);
if (dss_prev == dss_max) {
/* Success. */
dss_max = (void *)((intptr_t)dss_prev + incr);
malloc_mutex_unlock(&dss_mtx);
return (ret);
}
} while (dss_prev != (void *)-1);
}
malloc_mutex_unlock(&dss_mtx);
return (NULL);
}
static void *
chunk_recycle_dss(size_t size, bool zero)
{
extent_node_t *node, key;
key.addr = NULL;
key.size = size;
malloc_mutex_lock(&dss_mtx);
rb_nsearch(extent_node_t, link_szad, extent_szad_comp, &dss_chunks_szad,
&key, node);
if (node != NULL) {
void *ret = node->addr;
/* Remove node from the tree. */
extent_tree_szad_remove(&dss_chunks_szad, node);
if (node->size == size) {
extent_tree_ad_remove(&dss_chunks_ad, node);
base_node_dealloc(node);
} else {
/*
* Insert the remainder of node's address range as a
* smaller chunk. Its position within dss_chunks_ad
* does not change.
*/
assert(node->size > size);
node->addr = (void *)((uintptr_t)node->addr + size);
node->size -= size;
extent_tree_szad_insert(&dss_chunks_szad, node);
}
malloc_mutex_unlock(&dss_mtx);
if (zero)
memset(ret, 0, size);
return (ret);
}
malloc_mutex_unlock(&dss_mtx);
return (NULL);
}
#endif
static void *
chunk_alloc_mmap(size_t size)
{
void *ret;
size_t offset;
/*
* Ideally, there would be a way to specify alignment to mmap() (like
* NetBSD has), but in the absence of such a feature, we have to work
* hard to efficiently create aligned mappings. The reliable, but
* expensive method is to create a mapping that is over-sized, then
* trim the excess. However, that always results in at least one call
* to pages_unmap().
*
* A more optimistic approach is to try mapping precisely the right
* amount, then try to append another mapping if alignment is off. In
* practice, this works out well as long as the application is not
* interleaving mappings via direct mmap() calls. If we do run into a
* situation where there is an interleaved mapping and we are unable to
* extend an unaligned mapping, our best option is to momentarily
* revert to the reliable-but-expensive method. This will tend to
* leave a gap in the memory map that is too small to cause later
* problems for the optimistic method.
*/
ret = pages_map(NULL, size);
if (ret == NULL)
return (NULL);
offset = CHUNK_ADDR2OFFSET(ret);
if (offset != 0) {
/* Try to extend chunk boundary. */
if (pages_map((void *)((uintptr_t)ret + size),
chunksize - offset) == NULL) {
/*
* Extension failed. Clean up, then revert to the
* reliable-but-expensive method.
*/
pages_unmap(ret, size);
/* Beware size_t wrap-around. */
if (size + chunksize <= size)
return NULL;
ret = pages_map(NULL, size + chunksize);
if (ret == NULL)
return (NULL);
/* Clean up unneeded leading/trailing space. */
offset = CHUNK_ADDR2OFFSET(ret);
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);
}
} else {
/* Clean up unneeded leading space. */
pages_unmap(ret, chunksize - offset);
ret = (void *)((uintptr_t)ret + (chunksize - offset));
}
}
return (ret);
}
static void *
chunk_alloc(size_t size, bool zero)
{
void *ret;
assert(size != 0);
assert((size & chunksize_mask) == 0);
#ifdef MALLOC_DSS
if (opt_dss) {
ret = chunk_recycle_dss(size, zero);
if (ret != NULL) {
goto RETURN;
}
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:
#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
assert(CHUNK_ADDR2BASE(ret) == ret);
return (ret);
}
#ifdef MALLOC_DSS
static extent_node_t *
chunk_dealloc_dss_record(void *chunk, size_t size)
{
extent_node_t *node, *prev, key;
key.addr = (void *)((uintptr_t)chunk + size);
rb_nsearch(extent_node_t, link_ad, extent_ad_comp, &dss_chunks_ad,
&key, node);
/* Try to coalesce forward. */
if (node != NULL && node->addr == key.addr) {
/*
* Coalesce chunk with the following address range. This does
* not change the position within dss_chunks_ad, so only
* remove/insert from/into dss_chunks_szad.
*/
extent_tree_szad_remove(&dss_chunks_szad, node);
node->addr = chunk;
node->size += size;
extent_tree_szad_insert(&dss_chunks_szad, node);
} else {
/*
* Coalescing forward failed, so insert a new node. Drop
* dss_mtx during node allocation, since it is possible that a
* new base chunk will be allocated.
*/
malloc_mutex_unlock(&dss_mtx);
node = base_node_alloc();
malloc_mutex_lock(&dss_mtx);
if (node == NULL)
return (NULL);
node->addr = chunk;
node->size = size;
extent_tree_ad_insert(&dss_chunks_ad, node);
extent_tree_szad_insert(&dss_chunks_szad, node);
}
/* Try to coalesce backward. */
rb_prev(extent_node_t, link_ad, extent_ad_comp, &dss_chunks_ad, node,
prev);
if (prev != NULL && (void *)((uintptr_t)prev->addr + prev->size) ==
chunk) {
/*
* Coalesce chunk with the previous address range. This does
* not change the position within dss_chunks_ad, so only
* remove/insert node from/into dss_chunks_szad.
*/
extent_tree_szad_remove(&dss_chunks_szad, prev);
extent_tree_ad_remove(&dss_chunks_ad, prev);
extent_tree_szad_remove(&dss_chunks_szad, node);
node->addr = prev->addr;
node->size += prev->size;
extent_tree_szad_insert(&dss_chunks_szad, node);
base_node_dealloc(prev);
}
return (node);
}
static bool
chunk_dealloc_dss(void *chunk, size_t size)
{
malloc_mutex_lock(&dss_mtx);
if ((uintptr_t)chunk >= (uintptr_t)dss_base
&& (uintptr_t)chunk < (uintptr_t)dss_max) {
extent_node_t *node;
/* Try to coalesce with other unused chunks. */
node = chunk_dealloc_dss_record(chunk, size);
if (node != NULL) {
chunk = node->addr;
size = node->size;
}
/* Get the current end of the DSS. */
dss_max = 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 ((void *)((uintptr_t)chunk + size) == dss_max
&& (dss_prev = sbrk(-(intptr_t)size)) == dss_max) {
/* Success. */
dss_max = (void *)((intptr_t)dss_prev - (intptr_t)size);
if (node != NULL) {
extent_tree_szad_remove(&dss_chunks_szad, node);
extent_tree_ad_remove(&dss_chunks_ad, node);
base_node_dealloc(node);
}
malloc_mutex_unlock(&dss_mtx);
} else {
malloc_mutex_unlock(&dss_mtx);
madvise(chunk, size, MADV_FREE);
}
return (false);
}
malloc_mutex_unlock(&dss_mtx);
return (true);
}
#endif
static void
chunk_dealloc_mmap(void *chunk, size_t size)
{
pages_unmap(chunk, size);
}
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);
#ifdef MALLOC_STATS
stats_chunks.curchunks -= (size / chunksize);
#endif
#ifdef MALLOC_DSS
if (opt_dss) {
if (chunk_dealloc_dss(chunk, size) == false)
return;
}
if (opt_mmap)
#endif
chunk_dealloc_mmap(chunk, size);
}
/*
* 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. */
return (arenas[0]);
}
ret = arenas_map;
if (ret == NULL) {
ret = choose_arena_hard();
assert(ret != NULL);
}
#else
if (__isthreaded && narenas > 1) {
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_BALANCE
/* Seed the PRNG used for arena load balancing. */
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)
{
uintptr_t a_chunk = (uintptr_t)a;
uintptr_t b_chunk = (uintptr_t)b;
assert(a != NULL);
assert(b != NULL);
return ((a_chunk > b_chunk) - (a_chunk < b_chunk));
}
/* Wrap large red-black tree macros in functions. */
static void
arena_chunk_tree_insert(arena_chunk_tree_t *tree, arena_chunk_t *chunk)
{
rb_insert(arena_chunk_t, link, arena_chunk_comp, tree, chunk);
}
static void
arena_chunk_tree_remove(arena_chunk_tree_t *tree, arena_chunk_t *chunk)
{
rb_remove(arena_chunk_t, link, arena_chunk_comp, tree, chunk);
}
static inline int
arena_run_comp(arena_run_t *a, arena_run_t *b)
{
uintptr_t a_run = (uintptr_t)a;
uintptr_t b_run = (uintptr_t)b;
assert(a != NULL);
assert(b != NULL);
return ((a_run > b_run) - (a_run < b_run));
}
/* Wrap large red-black tree macros in functions. */
static void
arena_run_tree_insert(arena_run_tree_t *tree, arena_run_t *run)
{
rb_insert(arena_run_t, link, arena_run_comp, tree, run);
}
static void
arena_run_tree_remove(arena_run_tree_t *tree, arena_run_t *run)
{
rb_remove(arena_run_t, link, arena_run_comp, tree, run);
}
static extent_node_t *
arena_chunk_node_alloc(arena_chunk_t *chunk)
{
extent_node_t *ret;
rb_first(extent_node_t, link_ad, &chunk->nodes, ret);
if (ret != NULL)
extent_tree_ad_remove(&chunk->nodes, ret);
else {
ret = chunk->nodes_past;
chunk->nodes_past = (extent_node_t *)
((uintptr_t)chunk->nodes_past + sizeof(extent_node_t));
assert((uintptr_t)ret + sizeof(extent_node_t) <=
(uintptr_t)chunk + (arena_chunk_header_npages <<
pagesize_2pow));
}
return (ret);
}
static void
arena_chunk_node_dealloc(arena_chunk_t *chunk, extent_node_t *node)
{
node->addr = (void *)node;
extent_tree_ad_insert(&chunk->nodes, node);
}
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);
assert(regind < bin->nregs);
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);
assert(regind < bin->nregs);
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 run 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 small,
bool zero)
{
arena_chunk_t *chunk;
size_t run_ind, total_pages, need_pages, rem_pages, i;
extent_node_t *nodeA, *nodeB, key;
/* Insert a node into runs_alloced_ad for the first part of the run. */
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
nodeA = arena_chunk_node_alloc(chunk);
nodeA->addr = run;
nodeA->size = size;
extent_tree_ad_insert(&arena->runs_alloced_ad, nodeA);
key.addr = run;
rb_search(extent_node_t, link_ad, extent_ad_comp, &arena->runs_avail_ad,
&key, nodeB);
assert(nodeB != NULL);
run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
>> pagesize_2pow);
total_pages = nodeB->size >> pagesize_2pow;
need_pages = (size >> pagesize_2pow);
assert(need_pages > 0);
assert(need_pages <= total_pages);
assert(need_pages <= CHUNK_MAP_POS_MASK || small == false);
rem_pages = total_pages - need_pages;
for (i = 0; i < need_pages; i++) {
/* Zero if necessary. */
if (zero) {
if ((chunk->map[run_ind + i] & CHUNK_MAP_UNTOUCHED)
== 0) {
memset((void *)((uintptr_t)chunk + ((run_ind
+ i) << pagesize_2pow)), 0, pagesize);
/* CHUNK_MAP_UNTOUCHED is cleared below. */
}
}
/* Update dirty page accounting. */
if (chunk->map[run_ind + i] & CHUNK_MAP_DIRTY) {
chunk->ndirty--;
arena->ndirty--;
}
/* Initialize the chunk map. */
if (small)
chunk->map[run_ind + i] = (uint8_t)i;
else
chunk->map[run_ind + i] = CHUNK_MAP_LARGE;
}
/* Keep track of trailing unused pages for later use. */
extent_tree_szad_remove(&arena->runs_avail_szad, nodeB);
if (rem_pages > 0) {
/*
* Update nodeB in runs_avail_*. Its position within
* runs_avail_ad does not change.
*/
nodeB->addr = (void *)((uintptr_t)nodeB->addr + size);
nodeB->size -= size;
extent_tree_szad_insert(&arena->runs_avail_szad, nodeB);
} else {
/* Remove nodeB from runs_avail_*. */
extent_tree_ad_remove(&arena->runs_avail_ad, nodeB);
arena_chunk_node_dealloc(chunk, nodeB);
}
chunk->pages_used += need_pages;
}
static arena_chunk_t *
arena_chunk_alloc(arena_t *arena)
{
arena_chunk_t *chunk;
extent_node_t *node;
if (arena->spare != NULL) {
chunk = arena->spare;
arena->spare = NULL;
} else {
chunk = (arena_chunk_t *)chunk_alloc(chunksize, true);
if (chunk == NULL)
return (NULL);
#ifdef MALLOC_STATS
arena->stats.mapped += chunksize;
#endif
chunk->arena = arena;
arena_chunk_tree_insert(&arena->chunks, chunk);
/*
* Claim that no pages are in use, since the header is merely
* overhead.
*/
chunk->pages_used = 0;
chunk->ndirty = 0;
/*
* Initialize the map to contain one maximal free untouched
* run.
*/
memset(chunk->map, (CHUNK_MAP_LARGE | CHUNK_MAP_POS_MASK),
arena_chunk_header_npages);
memset(&chunk->map[arena_chunk_header_npages],
CHUNK_MAP_UNTOUCHED, (chunk_npages -
arena_chunk_header_npages));
/* Initialize the tree of unused extent nodes. */
rb_tree_new(extent_node_t, link_ad, &chunk->nodes);
chunk->nodes_past = (extent_node_t *)QUANTUM_CEILING(
(uintptr_t)&chunk->map[chunk_npages]);
}
/* Insert the run into the runs_avail_* red-black trees. */
node = arena_chunk_node_alloc(chunk);
node->addr = (void *)((uintptr_t)chunk + (arena_chunk_header_npages <<
pagesize_2pow));
node->size = chunksize - (arena_chunk_header_npages << pagesize_2pow);
extent_tree_szad_insert(&arena->runs_avail_szad, node);
extent_tree_ad_insert(&arena->runs_avail_ad, node);
return (chunk);
}
static void
arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
{
extent_node_t *node, key;
if (arena->spare != NULL) {
arena_chunk_tree_remove(&chunk->arena->chunks, arena->spare);
arena->ndirty -= arena->spare->ndirty;
chunk_dealloc((void *)arena->spare, chunksize);
#ifdef MALLOC_STATS
arena->stats.mapped -= chunksize;
#endif
}
/*
* Remove run from the runs trees, regardless of whether this chunk
* will be cached, so that the arena does not use it. Dirty page
* flushing only uses the chunks tree, so leaving this chunk in that
* tree is sufficient for that purpose.
*/
key.addr = (void *)((uintptr_t)chunk + (arena_chunk_header_npages <<
pagesize_2pow));
rb_search(extent_node_t, link_ad, extent_ad_comp, &arena->runs_avail_ad,
&key, node);
assert(node != NULL);
extent_tree_szad_remove(&arena->runs_avail_szad, node);
extent_tree_ad_remove(&arena->runs_avail_ad, node);
arena_chunk_node_dealloc(chunk, node);
arena->spare = chunk;
}
static arena_run_t *
arena_run_alloc(arena_t *arena, size_t size, bool small, bool zero)
{
arena_chunk_t *chunk;
arena_run_t *run;
extent_node_t *node, key;
assert(size <= (chunksize - (arena_chunk_header_npages <<
pagesize_2pow)));
assert((size & pagesize_mask) == 0);
/* Search the arena's chunks for the lowest best fit. */
key.addr = NULL;
key.size = size;
rb_nsearch(extent_node_t, link_szad, extent_szad_comp,
&arena->runs_avail_szad, &key, node);
if (node != NULL) {
run = (arena_run_t *)node->addr;
arena_run_split(arena, run, size, small, zero);
return (run);
}
/*
* 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, small, zero);
return (run);
}
static void
arena_purge(arena_t *arena)
{
arena_chunk_t *chunk;
#ifdef MALLOC_DEBUG
size_t ndirty;
ndirty = 0;
rb_foreach_begin(arena_chunk_t, link, &arena->chunks, chunk) {
ndirty += chunk->ndirty;
} rb_foreach_end(arena_chunk_t, link, &arena->chunks, chunk)
assert(ndirty == arena->ndirty);
#endif
assert(arena->ndirty > opt_dirty_max);
#ifdef MALLOC_STATS
arena->stats.npurge++;
#endif
/*
* Iterate downward through chunks until enough dirty memory has been
* purged.
*/
rb_foreach_reverse_begin(arena_chunk_t, link, &arena->chunks, chunk) {
if (chunk->ndirty > 0) {
size_t i;
for (i = chunk_npages - 1; i >=
arena_chunk_header_npages; i--) {
if (chunk->map[i] & CHUNK_MAP_DIRTY) {
size_t npages;
chunk->map[i] = (CHUNK_MAP_LARGE |
CHUNK_MAP_POS_MASK);
chunk->ndirty--;
arena->ndirty--;
/* Find adjacent dirty run(s). */
for (npages = 1; i >
arena_chunk_header_npages &&
(chunk->map[i - 1] &
CHUNK_MAP_DIRTY); npages++) {
i--;
chunk->map[i] = (CHUNK_MAP_LARGE
| CHUNK_MAP_POS_MASK);
chunk->ndirty--;
arena->ndirty--;
}
madvise((void *)((uintptr_t)chunk + (i
<< pagesize_2pow)), pagesize *
npages, MADV_FREE);
#ifdef MALLOC_STATS
arena->stats.nmadvise++;
arena->stats.purged += npages;
#endif
if (arena->ndirty <= (opt_dirty_max >>
1))
return;
}
}
}
} rb_foreach_reverse_end(arena_chunk_t, link, &arena->chunks, chunk)
}
static void
arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
{
arena_chunk_t *chunk;
extent_node_t *nodeA, *nodeB, *nodeC, key;
size_t size, run_ind, run_pages;
/* Remove run from runs_alloced_ad. */
key.addr = run;
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, nodeB);
assert(nodeB != NULL);
extent_tree_ad_remove(&arena->runs_alloced_ad, nodeB);
size = nodeB->size;
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);
/* Subtract pages from count of pages used in chunk. */
chunk->pages_used -= run_pages;
if (dirty) {
size_t i;
for (i = 0; i < run_pages; i++) {
assert((chunk->map[run_ind + i] & CHUNK_MAP_DIRTY) ==
0);
chunk->map[run_ind + i] |= CHUNK_MAP_DIRTY;
chunk->ndirty++;
arena->ndirty++;
}
}
#ifdef MALLOC_DEBUG
/* Set map elements to a bogus value in order to aid error detection. */
{
size_t i;
for (i = 0; i < run_pages; i++) {
chunk->map[run_ind + i] |= (CHUNK_MAP_LARGE |
CHUNK_MAP_POS_MASK);
}
}
#endif
/* Try to coalesce forward. */
key.addr = (void *)((uintptr_t)run + size);
rb_nsearch(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_avail_ad, &key, nodeC);
if (nodeC != NULL && nodeC->addr == key.addr) {
/*
* Coalesce forward. This does not change the position within
* runs_avail_ad, so only remove/insert from/into
* runs_avail_szad.
*/
extent_tree_szad_remove(&arena->runs_avail_szad, nodeC);
nodeC->addr = (void *)run;
nodeC->size += size;
extent_tree_szad_insert(&arena->runs_avail_szad, nodeC);
arena_chunk_node_dealloc(chunk, nodeB);
nodeB = nodeC;
} else {
/*
* Coalescing forward failed, so insert nodeB into runs_avail_*.
*/
extent_tree_szad_insert(&arena->runs_avail_szad, nodeB);
extent_tree_ad_insert(&arena->runs_avail_ad, nodeB);
}
/* Try to coalesce backward. */
rb_prev(extent_node_t, link_ad, extent_ad_comp, &arena->runs_avail_ad,
nodeB, nodeA);
if (nodeA != NULL && (void *)((uintptr_t)nodeA->addr + nodeA->size) ==
(void *)run) {
/*
* Coalesce with previous run. This does not change nodeB's
* position within runs_avail_ad, so only remove/insert
* from/into runs_avail_szad.
*/
extent_tree_szad_remove(&arena->runs_avail_szad, nodeA);
extent_tree_ad_remove(&arena->runs_avail_ad, nodeA);
extent_tree_szad_remove(&arena->runs_avail_szad, nodeB);
nodeB->addr = nodeA->addr;
nodeB->size += nodeA->size;
extent_tree_szad_insert(&arena->runs_avail_szad, nodeB);
arena_chunk_node_dealloc(chunk, nodeA);
}
/* Deallocate chunk if it is now completely unused. */
if (chunk->pages_used == 0)
arena_chunk_dealloc(arena, chunk);
/* Enforce opt_dirty_max. */
if (arena->ndirty > opt_dirty_max)
arena_purge(arena);
}
static void
arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk, extent_node_t *nodeB,
arena_run_t *run, size_t oldsize, size_t newsize)
{
extent_node_t *nodeA;
assert(nodeB->addr == run);
assert(nodeB->size == oldsize);
assert(oldsize > newsize);
/*
* Update the run's node in runs_alloced_ad. Its position does not
* change.
*/
nodeB->addr = (void *)((uintptr_t)run + (oldsize - newsize));
nodeB->size = newsize;
/*
* Insert a node into runs_alloced_ad so that arena_run_dalloc() can
* treat the leading run as separately allocated.
*/
nodeA = arena_chunk_node_alloc(chunk);
nodeA->addr = (void *)run;
nodeA->size = oldsize - newsize;
extent_tree_ad_insert(&arena->runs_alloced_ad, nodeA);
arena_run_dalloc(arena, (arena_run_t *)run, false);
}
static void
arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk, extent_node_t *nodeA,
arena_run_t *run, size_t oldsize, size_t newsize, bool dirty)
{
extent_node_t *nodeB;
assert(nodeA->addr == run);
assert(nodeA->size == oldsize);
assert(oldsize > newsize);
/*
* Update the run's node in runs_alloced_ad. Its position does not
* change.
*/
nodeA->size = newsize;
/*
* Insert a node into runs_alloced_ad so that arena_run_dalloc() can
* treat the trailing run as separately allocated.
*/
nodeB = arena_chunk_node_alloc(chunk);
nodeB->addr = (void *)((uintptr_t)run + newsize);
nodeB->size = oldsize - newsize;
extent_tree_ad_insert(&arena->runs_alloced_ad, nodeB);
arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)run + newsize),
dirty);
}
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. */
rb_first(arena_run_t, link, &bin->runs, run);
if (run != NULL) {
/* run is guaranteed to have available space. */
arena_run_tree_remove(&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, true, 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)
arena_lock_balance_hard(arena);
}
}
static void
arena_lock_balance_hard(arena_t *arena)
{
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 inline void *
arena_malloc_small(arena_t *arena, size_t size, bool zero)
{
void *ret;
arena_bin_t *bin;
arena_run_t *run;
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);
return (ret);
}
static void *
arena_malloc_large(arena_t *arena, size_t size, bool zero)
{
void *ret;
/* 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, false, 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_malloc(arena_t *arena, size_t size, bool zero)
{
assert(arena != NULL);
assert(arena->magic == ARENA_MAGIC);
assert(size != 0);
assert(QUANTUM_CEILING(size) <= arena_maxclass);
if (size <= bin_maxclass) {
return (arena_malloc_small(arena, size, zero));
} else
return (arena_malloc_large(arena, size, zero));
}
static inline void *
imalloc(size_t size)
{
assert(size != 0);
if (size <= arena_maxclass)
return (arena_malloc(choose_arena(), size, false));
else
return (huge_malloc(size, false));
}
static inline void *
icalloc(size_t size)
{
if (size <= arena_maxclass)
return (arena_malloc(choose_arena(), size, true));
else
return (huge_malloc(size, true));
}
/* 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;
extent_node_t *node, key;
assert((size & pagesize_mask) == 0);
assert((alignment & pagesize_mask) == 0);
#ifdef MALLOC_BALANCE
arena_lock_balance(arena);
#else
malloc_spin_lock(&arena->lock);
#endif
ret = (void *)arena_run_alloc(arena, alloc_size, false, 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) {
/*
* Update the run's node in runs_alloced_ad. Its position
* does not change.
*/
key.addr = ret;
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, node);
assert(node != NULL);
arena_run_trim_tail(arena, chunk, node, ret, alloc_size, size,
false);
} else {
size_t leadsize, trailsize;
/*
* Update the run's node in runs_alloced_ad. Its position
* does not change.
*/
key.addr = ret;
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, node);
assert(node != NULL);
leadsize = alignment - offset;
if (leadsize > 0) {
arena_run_trim_head(arena, chunk, node, ret, alloc_size,
alloc_size - leadsize);
ret = (void *)((uintptr_t)ret + leadsize);
}
trailsize = alloc_size - leadsize - size;
if (trailsize != 0) {
/* Trim trailing space. */
assert(trailsize < alloc_size);
arena_run_trim_tail(arena, chunk, node, ret, size +
trailsize, size, false);
}
}
#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);
}
static inline 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);
}
/* 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;
size_t pageind;
assert(ptr != NULL);
assert(CHUNK_ADDR2BASE(ptr) != ptr);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
mapelm = chunk->map[pageind];
if ((mapelm & CHUNK_MAP_LARGE) == 0) {
arena_run_t *run;
/* Small allocation size is in the run header. */
pageind -= (mapelm & CHUNK_MAP_POS_MASK);
run = (arena_run_t *)((uintptr_t)chunk + (pageind <<
pagesize_2pow));
assert(run->magic == ARENA_RUN_MAGIC);
ret = run->bin->reg_size;
} else {
arena_t *arena = chunk->arena;
extent_node_t *node, key;
/* Large allocation size is in the extent tree. */
assert((mapelm & CHUNK_MAP_POS_MASK) == 0);
arena = chunk->arena;
malloc_spin_lock(&arena->lock);
key.addr = (void *)ptr;
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, node);
assert(node != NULL);
ret = node->size;
malloc_spin_unlock(&arena->lock);
}
return (ret);
}
static inline 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 {
extent_node_t *node, key;
/* Chunk (huge allocation). */
malloc_mutex_lock(&huge_mtx);
/* Extract from tree of huge allocations. */
key.addr = __DECONST(void *, ptr);
rb_search(extent_node_t, link_ad, extent_ad_comp, &huge, &key,
node);
assert(node != NULL);
ret = node->size;
malloc_mutex_unlock(&huge_mtx);
}
return (ret);
}
static inline void
arena_dalloc_small(arena_t *arena, arena_chunk_t *chunk, void *ptr,
size_t pageind, arena_chunk_map_t mapelm)
{
arena_run_t *run;
arena_bin_t *bin;
size_t size;
pageind -= (mapelm & CHUNK_MAP_POS_MASK);
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.
*/
arena_run_tree_remove(&bin->runs, run);
}
#ifdef MALLOC_DEBUG
run->magic = 0;
#endif
arena_run_dalloc(arena, run, true);
#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. */
arena_run_tree_insert(&bin->runs, bin->runcur);
}
bin->runcur = run;
} else
arena_run_tree_insert(&bin->runs, run);
}
#ifdef MALLOC_STATS
arena->stats.allocated_small -= size;
arena->stats.ndalloc_small++;
#endif
}
static void
arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk, void *ptr)
{
/* Large allocation. */
malloc_spin_lock(&arena->lock);
#ifndef MALLOC_STATS
if (opt_junk)
#endif
{
extent_node_t *node, key;
size_t size;
key.addr = ptr;
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, node);
assert(node != NULL);
size = node->size;
#ifdef MALLOC_STATS
if (opt_junk)
#endif
memset(ptr, 0x5a, size);
#ifdef MALLOC_STATS
arena->stats.allocated_large -= size;
#endif
}
#ifdef MALLOC_STATS
arena->stats.ndalloc_large++;
#endif
arena_run_dalloc(arena, (arena_run_t *)ptr, true);
malloc_spin_unlock(&arena->lock);
}
static inline void
arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
{
size_t 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 & CHUNK_MAP_LARGE) == 0) {
/* Small allocation. */
malloc_spin_lock(&arena->lock);
arena_dalloc_small(arena, chunk, ptr, pageind, *mapelm);
malloc_spin_unlock(&arena->lock);
} else {
assert((*mapelm & CHUNK_MAP_POS_MASK) == 0);
arena_dalloc_large(arena, chunk, ptr);
}
}
static inline void
idalloc(void *ptr)
{
arena_chunk_t *chunk;
assert(ptr != NULL);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr)
arena_dalloc(chunk->arena, chunk, ptr);
else
huge_dalloc(ptr);
}
static void
arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk, void *ptr,
size_t size, size_t oldsize)
{
extent_node_t *node, key;
assert(size < oldsize);
/*
* Shrink the run, and make trailing pages available for other
* allocations.
*/
key.addr = (void *)((uintptr_t)ptr);
#ifdef MALLOC_BALANCE
arena_lock_balance(arena);
#else
malloc_spin_lock(&arena->lock);
#endif
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, node);
assert(node != NULL);
arena_run_trim_tail(arena, chunk, node, (arena_run_t *)ptr, oldsize,
size, true);
#ifdef MALLOC_STATS
arena->stats.allocated_large -= oldsize - size;
#endif
malloc_spin_unlock(&arena->lock);
}
static bool
arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk, void *ptr,
size_t size, size_t oldsize)
{
extent_node_t *nodeC, key;
/* Try to extend the run. */
assert(size > oldsize);
key.addr = (void *)((uintptr_t)ptr + oldsize);
#ifdef MALLOC_BALANCE
arena_lock_balance(arena);
#else
malloc_spin_lock(&arena->lock);
#endif
rb_search(extent_node_t, link_ad, extent_ad_comp, &arena->runs_avail_ad,
&key, nodeC);
if (nodeC != NULL && oldsize + nodeC->size >= size) {
extent_node_t *nodeA, *nodeB;
/*
* The next run is available and sufficiently large. Split the
* following run, then merge the first part with the existing
* allocation. This results in a bit more tree manipulation
* than absolutely necessary, but it substantially simplifies
* the code.
*/
arena_run_split(arena, (arena_run_t *)nodeC->addr, size -
oldsize, false, false);
key.addr = ptr;
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, nodeA);
assert(nodeA != NULL);
key.addr = (void *)((uintptr_t)ptr + oldsize);
rb_search(extent_node_t, link_ad, extent_ad_comp,
&arena->runs_alloced_ad, &key, nodeB);
assert(nodeB != NULL);
nodeA->size += nodeB->size;
extent_tree_ad_remove(&arena->runs_alloced_ad, nodeB);
arena_chunk_node_dealloc(chunk, nodeB);
#ifdef MALLOC_STATS
arena->stats.allocated_large += size - oldsize;
#endif
malloc_spin_unlock(&arena->lock);
return (false);
}
malloc_spin_unlock(&arena->lock);
return (true);
}
/*
* Try to resize a large allocation, in order to avoid copying. This will
* always fail if growing an object, and the following run is already in use.
*/
static bool
arena_ralloc_large(void *ptr, size_t size, size_t oldsize)
{
size_t psize;
psize = PAGE_CEILING(size);
if (psize == oldsize) {
/* Same size class. */
if (opt_junk && size < oldsize) {
memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize -
size);
}
return (false);
} else {
arena_chunk_t *chunk;
arena_t *arena;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
arena = chunk->arena;
assert(arena->magic == ARENA_MAGIC);
if (psize < oldsize) {
/* Fill before shrinking in order avoid a race. */
if (opt_junk) {
memset((void *)((uintptr_t)ptr + size), 0x5a,
oldsize - size);
}
arena_ralloc_large_shrink(arena, chunk, ptr, psize,
oldsize);
return (false);
} else {
bool ret = arena_ralloc_large_grow(arena, chunk, ptr,
psize, oldsize);
if (ret == false && opt_zero) {
memset((void *)((uintptr_t)ptr + oldsize), 0,
size - oldsize);
}
return (ret);
}
}
}
static void *
arena_ralloc(void *ptr, size_t size, size_t oldsize)
{
void *ret;
size_t copysize;
/* Try to avoid moving the allocation. */
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; /* Same size class. */
} 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; /* Same size class. */
} else if (size <= bin_maxclass) {
if (oldsize > small_max && oldsize <= bin_maxclass &&
pow2_ceil(size) == pow2_ceil(oldsize))
goto IN_PLACE; /* Same size class. */
} else if (oldsize > bin_maxclass && oldsize <= arena_maxclass) {
assert(size > bin_maxclass);
if (arena_ralloc_large(ptr, size, oldsize) == false)
return (ptr);
}
/*
* If we get here, then size and oldsize are different enough that we
* need to move the object. 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(). */
copysize = (size < oldsize) ? size : oldsize;
memcpy(ret, ptr, copysize);
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 *
iralloc(void *ptr, size_t size)
{
size_t oldsize;
assert(ptr != NULL);
assert(size != 0);
oldsize = isalloc(ptr);
if (size <= arena_maxclass)
return (arena_ralloc(ptr, size, oldsize));
else
return (huge_ralloc(ptr, size, oldsize));
}
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_tree_new(arena_chunk_t, link, &arena->chunks);
arena->spare = NULL;
arena->ndirty = 0;
rb_tree_new(extent_node_t, link_szad, &arena->runs_avail_szad);
rb_tree_new(extent_node_t, link_ad, &arena->runs_avail_ad);
rb_tree_new(extent_node_t, link_ad, &arena->runs_alloced_ad);
#ifdef MALLOC_BALANCE
arena->contention = 0;
#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_tree_new(arena_run_t, link, &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_tree_new(arena_run_t, link, &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_tree_new(arena_run_t, link, &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;
extent_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 an extent node with which to track the chunk. */
node = base_node_alloc();
if (node == NULL)
return (NULL);
ret = chunk_alloc(csize, zero);
if (ret == NULL) {
base_node_dealloc(node);
return (NULL);
}
/* Insert node into huge. */
node->addr = ret;
node->size = csize;
malloc_mutex_lock(&huge_mtx);
extent_tree_ad_insert(&huge, node);
#ifdef MALLOC_STATS
huge_nmalloc++;
huge_allocated += csize;
#endif
malloc_mutex_unlock(&huge_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;
extent_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 an extent node with which to track the chunk. */
node = base_node_alloc();
if (node == NULL)
return (NULL);
ret = chunk_alloc(alloc_size, false);
if (ret == NULL) {
base_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->addr = ret;
node->size = chunk_size;
malloc_mutex_lock(&huge_mtx);
extent_tree_ad_insert(&huge, node);
#ifdef MALLOC_STATS
huge_nmalloc++;
huge_allocated += chunk_size;
#endif
malloc_mutex_unlock(&huge_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;
size_t copysize;
/* 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);
copysize = (size < oldsize) ? size : oldsize;
memcpy(ret, ptr, copysize);
idalloc(ptr);
return (ret);
}
static void
huge_dalloc(void *ptr)
{
extent_node_t *node, key;
malloc_mutex_lock(&huge_mtx);
/* Extract from tree of huge allocations. */
key.addr = ptr;
rb_search(extent_node_t, link_ad, extent_ad_comp, &huge, &key, node);
assert(node != NULL);
assert(node->addr == ptr);
extent_tree_ad_remove(&huge, node);
#ifdef MALLOC_STATS
huge_ndalloc++;
huge_allocated -= node->size;
#endif
malloc_mutex_unlock(&huge_mtx);
/* Unmap chunk. */
#ifdef MALLOC_DSS
if (opt_dss && opt_junk)
memset(node->addr, 0x5a, node->size);
#endif
chunk_dealloc(node->addr, node->size);
base_node_dealloc(node);
}
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_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_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("Max dirty pages per arena: ",
umax2s(opt_dirty_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(&huge_mtx);
allocated += huge_allocated;
mapped = stats_chunks.curchunks * chunksize;
malloc_mutex_unlock(&huge_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(&huge_mtx);
chunks_stats = stats_chunks;
malloc_mutex_unlock(&huge_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;
}
}
/* 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 MALLOC_OUT;
}
}
MALLOC_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 'f':
opt_dirty_max >>= 1;
break;
case 'F':
if (opt_dirty_max == 0)
opt_dirty_max = 1;
else if ((opt_dirty_max << 1) != 0)
opt_dirty_max <<= 1;
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':
if (opt_chunk_2pow + 1 <
(sizeof(size_t) << 3))
opt_chunk_2pow++;
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);
{
size_t header_size;
/*
* Compute the header size such that it is large
* enough to contain the page map and enough nodes for the
* worst case: one node per non-header page plus one extra for
* situations where we briefly have one more node allocated
* than we will need.
*/
header_size = sizeof(arena_chunk_t) +
(sizeof(arena_chunk_map_t) * (chunk_npages - 1)) +
(sizeof(extent_node_t) * chunk_npages);
arena_chunk_header_npages = (header_size >> pagesize_2pow) +
((header_size & pagesize_mask) != 0);
}
arena_maxclass = chunksize - (arena_chunk_header_npages <<
pagesize_2pow);
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(&huge_mtx);
rb_tree_new(extent_node_t, link_ad, &huge);
#ifdef MALLOC_DSS
malloc_mutex_init(&dss_mtx);
dss_base = sbrk(0);
dss_prev = dss_base;
dss_max = dss_base;
rb_tree_new(extent_node_t, link_szad, &dss_chunks_szad);
rb_tree_new(extent_node_t, link_ad, &dss_chunks_ad);
#endif
#ifdef MALLOC_STATS
huge_nmalloc = 0;
huge_ndalloc = 0;
huge_allocated = 0;
#endif
/* 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_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 value doesn't really matter.
*/
#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(&huge_mtx);
#ifdef MALLOC_DSS
malloc_mutex_lock(&dss_mtx);
#endif
}
void
_malloc_postfork(void)
{
unsigned i;
/* Release all mutexes, now that fork() has completed. */
#ifdef MALLOC_DSS
malloc_mutex_unlock(&dss_mtx);
#endif
malloc_mutex_unlock(&huge_mtx);
malloc_mutex_unlock(&base_mtx);
malloc_spin_lock(&arenas_lock);
for (i = 0; i < narenas; i++) {
if (arenas[i] != NULL)
malloc_spin_unlock(&arenas[i]->lock);
}
malloc_spin_unlock(&arenas_lock);
}
/*
* End library-private functions.
*/
/******************************************************************************/
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