/*- * Copyright (C) 2006 Jason Evans . * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice(s), this list of conditions and the following disclaimer as * the first lines of this file unmodified other than the possible * addition of one or more copyright notices. * 2. Redistributions in binary form must reproduce the above copyright * notice(s), this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ******************************************************************************* * * This allocator implementation is designed to provide scalable performance * for multi-threaded programs on multi-processor systems. The following * features are included for this purpose: * * + Multiple arenas are used if there are multiple CPUs, which reduces lock * contention and cache sloshing. * * + Cache line sharing between arenas is avoided for internal data * structures. * * + Memory is managed in chunks and runs (chunks can be split into runs using * a binary buddy scheme), rather than as individual pages. This provides * a constant-time mechanism for associating allocations with particular * arenas. * * Allocation requests are rounded up to the nearest size class, and no record * of the original request size is maintained. Allocations are broken into * categories according to size class. Assuming runtime defaults, 4 kB pages * and a 16 byte quantum, the size classes in each category are as follows: * * |====================================| * | Category | Subcategory | Size | * |====================================| * | Small | Tiny | 2 | * | | | 4 | * | | | 8 | * | |----------------+--------| * | | Quantum-spaced | 16 | * | | | 32 | * | | | 48 | * | | | ... | * | | | 480 | * | | | 496 | * | | | 512 | * | |----------------+--------| * | | Sub-page | 1 kB | * | | | 2 kB | * |====================================| * | Large | 4 kB | * | | 8 kB | * | | 16 kB | * | | ... | * | | 256 kB | * | | 512 kB | * | | 1 MB | * |====================================| * | Huge | 2 MB | * | | 4 MB | * | | 6 MB | * | | ... | * |====================================| * * A different mechanism is used for each category: * * Small : Each size class is segregated into its own set of runs. Each run * maintains a bitmap of which regions are free/allocated. * * Large : Each allocation is backed by a dedicated run. Metadata are stored * in the associated arena chunk header maps. * * Huge : Each allocation is backed by a dedicated contiguous set of chunks. * Metadata are stored in a separate red-black tree. * ******************************************************************************* */ /* ******************************************************************************* * * Ring macros. * ******************************************************************************* */ /* Ring definitions. */ #define qr(a_type) struct { \ a_type *qre_next; \ a_type *qre_prev; \ } #define qr_initializer {NULL, NULL} /* Ring functions. */ #define qr_new(a_qr, a_field) do { \ (a_qr)->a_field.qre_next = (a_qr); \ (a_qr)->a_field.qre_prev = (a_qr); \ } while (0) #define qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next) #define qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev) #define qr_before_insert(a_qrelm, a_qr, a_field) do { \ (a_qr)->a_field.qre_prev = (a_qrelm)->a_field.qre_prev; \ (a_qr)->a_field.qre_next = (a_qrelm); \ (a_qr)->a_field.qre_prev->a_field.qre_next = (a_qr); \ (a_qrelm)->a_field.qre_prev = (a_qr); \ } while (0) #define qr_after_insert(a_qrelm, a_qr, a_field) do { \ (a_qr)->a_field.qre_next = (a_qrelm)->a_field.qre_next; \ (a_qr)->a_field.qre_prev = (a_qrelm); \ (a_qr)->a_field.qre_next->a_field.qre_prev = (a_qr); \ (a_qrelm)->a_field.qre_next = (a_qr); \ } while (0) #define qr_meld(a_qr_a, a_qr_b, a_type, a_field) do { \ a_type *t; \ (a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_b); \ (a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_a); \ t = (a_qr_a)->a_field.qre_prev; \ (a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev; \ (a_qr_b)->a_field.qre_prev = t; \ } while (0) /* * qr_meld() and qr_split() are functionally equivalent, so there's no need to * have two copies of the code. */ #define qr_split(a_qr_a, a_qr_b, a_type, a_field) \ qr_meld((a_qr_a), (a_qr_b), a_type, a_field) #define qr_remove(a_qr, a_field) do { \ (a_qr)->a_field.qre_prev->a_field.qre_next \ = (a_qr)->a_field.qre_next; \ (a_qr)->a_field.qre_next->a_field.qre_prev \ = (a_qr)->a_field.qre_prev; \ (a_qr)->a_field.qre_next = (a_qr); \ (a_qr)->a_field.qre_prev = (a_qr); \ } while (0) #define qr_foreach(var, a_qr, a_field) \ for ((var) = (a_qr); \ (var) != NULL; \ (var) = (((var)->a_field.qre_next != (a_qr)) \ ? (var)->a_field.qre_next : NULL)) #define qr_reverse_foreach(var, a_qr, a_field) \ for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL; \ (var) != NULL; \ (var) = (((var) != (a_qr)) \ ? (var)->a_field.qre_prev : NULL)) /******************************************************************************/ /* * In order to disable various extra features that may have negative * performance impacts, (assertions, expanded statistics), define * NO_MALLOC_EXTRAS. */ /* #define NO_MALLOC_EXTRAS */ #ifndef NO_MALLOC_EXTRAS # define MALLOC_DEBUG #endif #include __FBSDID("$FreeBSD$"); #include "libc_private.h" #ifdef MALLOC_DEBUG # define _LOCK_DEBUG #endif #include "spinlock.h" #include "namespace.h" #include #include #include #include #include #include #include #include #include /* Must come after several other sys/ includes. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "un-namespace.h" /* * Calculate statistics that can be used to get an idea of how well caching is * working. */ #ifndef NO_MALLOC_EXTRAS # define MALLOC_STATS #endif #ifndef MALLOC_DEBUG # ifndef NDEBUG # define NDEBUG # endif #endif #include #ifdef MALLOC_DEBUG /* Disable inlining to make debugging easier. */ # define inline #endif /* Size of stack-allocated buffer passed to strerror_r(). */ #define STRERROR_BUF 64 /* Minimum alignment of allocations is 2^QUANTUM_2POW_MIN bytes. */ #ifdef __i386__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR 4 # define USE_BRK #endif #ifdef __ia64__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR 8 #endif #ifdef __alpha__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR 8 # define NO_TLS #endif #ifdef __sparc64__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR 8 # define NO_TLS #endif #ifdef __amd64__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR 8 #endif #ifdef __arm__ # define QUANTUM_2POW_MIN 3 # define SIZEOF_PTR 4 # define USE_BRK # define NO_TLS #endif #ifdef __powerpc__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR 4 # define USE_BRK #endif /* sizeof(int) == (1 << SIZEOF_INT_2POW). */ #ifndef SIZEOF_INT_2POW # define SIZEOF_INT_2POW 2 #endif /* We can't use TLS in non-PIC programs, since TLS relies on loader magic. */ #if (!defined(PIC) && !defined(NO_TLS)) # define NO_TLS #endif /* * Size and alignment of memory chunks that are allocated by the OS's virtual * memory system. * * chunksize limits: * * 2^(pagesize_2pow - 1 + RUN_MIN_REGS_2POW) <= chunk_size <= 2^28 */ #define CHUNK_2POW_DEFAULT 21 #define CHUNK_2POW_MAX 28 /* * Maximum size of L1 cache line. This is used to avoid cache line aliasing, * so over-estimates are okay (up to a point), but under-estimates will * negatively affect performance. */ #define CACHELINE_2POW 6 #define CACHELINE ((size_t)(1 << CACHELINE_2POW)) /* * Maximum size class that is a multiple of the quantum, but not (necessarily) * a power of 2. Above this size, allocations are rounded up to the nearest * power of 2. */ #define SMALL_MAX_2POW_DEFAULT 9 #define SMALL_MAX_DEFAULT (1 << SMALL_MAX_2POW_DEFAULT) /* * Minimum number of regions that must fit into a run that serves quantum-size * bin allocations. * * Note that if this is set too low, space will be wasted if there are size * classes that are small enough that RUN_MIN_REGS regions don't fill a page. * If this is set too high, then the overhead of searching through the bitmap * that tracks region usage will become excessive. */ #define RUN_MIN_REGS_2POW 10 #define RUN_MIN_REGS (1 << RUN_MIN_REGS_2POW) /* * Maximum number of pages for a run that is used for bin allocations. * * Note that if this is set too low, then fragmentation for the largest bin * size classes will be high. If this is set too high, then even small * programs will often have to allocate more than two chunks early on. */ #define RUN_MAX_PAGES_2POW 4 #define RUN_MAX_PAGES (1 << RUN_MAX_PAGES_2POW) /******************************************************************************/ /* * Mutexes based on spinlocks. We can't use normal pthread mutexes, because * they require malloc()ed memory. */ typedef struct { spinlock_t lock; } malloc_mutex_t; /* Set to true once the allocator has been initialized. */ static bool malloc_initialized = false; /* Used to avoid initialization races. */ static malloc_mutex_t init_lock = {_SPINLOCK_INITIALIZER}; /******************************************************************************/ /* * Statistics data structures. */ #ifdef MALLOC_STATS typedef struct malloc_bin_stats_s malloc_bin_stats_t; struct malloc_bin_stats_s { /* * Number of allocation requests that corresponded to the size of this * bin. */ uint64_t nrequests; /* Total number of runs created for this bin's size class. */ uint64_t nruns; /* * Total number of run promotions/demotions for this bin's size class. */ uint64_t npromote; uint64_t ndemote; /* High-water mark for this bin. */ unsigned long highruns; /* Current number of runs in this bin. */ unsigned long curruns; }; typedef struct arena_stats_s arena_stats_t; struct arena_stats_s { /* Total byte count of allocated memory, not including overhead. */ size_t allocated; /* Number of times each function was called. */ uint64_t nmalloc; uint64_t ndalloc; uint64_t nmadvise; /* Number of large allocation requests. */ uint64_t large_nrequests; }; typedef struct chunk_stats_s chunk_stats_t; struct chunk_stats_s { /* Number of chunks that were allocated. */ uint64_t nchunks; /* High-water mark for number of chunks allocated. */ unsigned long highchunks; /* * Current number of chunks allocated. This value isn't maintained for * any other purpose, so keep track of it in order to be able to set * highchunks. */ unsigned long curchunks; }; #endif /* #ifdef MALLOC_STATS */ /******************************************************************************/ /* * Chunk data structures. */ /* Tree of chunks. */ typedef struct chunk_node_s chunk_node_t; struct chunk_node_s { /* Linkage for the chunk tree. */ RB_ENTRY(chunk_node_s) link; /* * Pointer to the chunk that this tree node is responsible for. In some * (but certainly not all) cases, this data structure is placed at the * beginning of the corresponding chunk, so this field may point to this * node. */ void *chunk; /* Total chunk size. */ size_t size; }; typedef struct chunk_tree_s chunk_tree_t; RB_HEAD(chunk_tree_s, chunk_node_s); /******************************************************************************/ /* * Arena data structures. */ typedef struct arena_s arena_t; typedef struct arena_bin_s arena_bin_t; typedef struct arena_chunk_map_s arena_chunk_map_t; struct arena_chunk_map_s { bool free:1; bool large:1; unsigned npages:15; /* Limiting factor for CHUNK_2POW_MAX. */ unsigned pos:15; }; /* Arena chunk header. */ typedef struct arena_chunk_s arena_chunk_t; struct arena_chunk_s { /* Arena that owns the chunk. */ arena_t *arena; /* Linkage for the arena's chunk tree. */ RB_ENTRY(arena_chunk_s) link; /* * Number of pages in use. This is maintained in order to make * detection of empty chunks fast. */ uint32_t pages_used; /* * Array of counters that keeps track of how many free runs of each * size are available in this chunk. This table is sized at compile * time, which is wasteful. However, due to unrelated rounding, this * doesn't actually waste any otherwise useful space. * * index == 2^n pages * * index | npages * ------+------- * 0 | 1 * 1 | 2 * 2 | 4 * 3 | 8 * : */ uint32_t nfree_runs[CHUNK_2POW_MAX/* - PAGE_SHIFT */]; /* Map of pages within chunk that keeps track of free/large/small. */ arena_chunk_map_t map[1]; /* Dynamically sized. */ }; typedef struct arena_chunk_tree_s arena_chunk_tree_t; RB_HEAD(arena_chunk_tree_s, arena_chunk_s); typedef struct arena_run_s arena_run_t; struct arena_run_s { /* Linkage for run rings. */ qr(arena_run_t) link; #ifdef MALLOC_DEBUG uint32_t magic; # define ARENA_RUN_MAGIC 0x384adf93 #endif /* Bin this run is associated with. */ arena_bin_t *bin; /* Bitmask of in-use regions (0: in use, 1: free). */ #define REGS_MASK_NELMS \ (1 << (RUN_MIN_REGS_2POW - SIZEOF_INT_2POW - 2)) unsigned regs_mask[REGS_MASK_NELMS]; /* Index of first element that might have a free region. */ unsigned regs_minelm; /* Number of free regions in run. */ unsigned nfree; /* * Current quartile for this run, one of: {RUN_QINIT, RUN_Q0, RUN_25, * RUN_Q50, RUN_Q75, RUN_Q100}. */ #define RUN_QINIT 0 #define RUN_Q0 1 #define RUN_Q25 2 #define RUN_Q50 3 #define RUN_Q75 4 #define RUN_Q100 5 unsigned quartile; /* * Limits on the number of free regions for the fullness quartile this * run is currently in. If nfree goes outside these limits, the run * is moved to a different fullness quartile. */ unsigned free_max; unsigned free_min; }; /* Used for run ring headers, where the run isn't actually used. */ typedef struct arena_run_link_s arena_run_link_t; struct arena_run_link_s { /* Linkage for run rings. */ qr(arena_run_t) link; }; struct arena_bin_s { /* * Current run being used to service allocations of this bin's size * class. */ arena_run_t *runcur; /* * Links into rings of runs, of various fullnesses (names indicate * approximate lower bounds). A new run conceptually starts off in * runsinit, and it isn't inserted into the runs0 ring until it * reaches 25% full (hysteresis mechanism). For the run to be moved * again, it must become either empty or 50% full. Thus, each ring * contains runs that are within 50% above the advertised fullness for * the ring. This provides a low-overhead mechanism for segregating * runs into approximate fullness classes. * * Conceptually, there is a runs100 that contains completely full runs. * Since we don't need to search for these runs though, no runs100 ring * is actually maintained. * * These rings are useful when looking for an existing run to use when * runcur is no longer usable. We look for usable runs in the * following order: * * 1) runs50 * 2) runs25 * 3) runs0 * 4) runs75 * * runs75 isn't a good place to look, because it contains runs that may * be nearly completely full. Still, we look there as a last resort in * order to avoid allocating a new run if at all possible. */ /* arena_run_link_t runsinit; 0% <= fullness < 25% */ arena_run_link_t runs0; /* 0% < fullness < 50% */ arena_run_link_t runs25; /* 25% < fullness < 75% */ arena_run_link_t runs50; /* 50% < fullness < 100% */ arena_run_link_t runs75; /* 75% < fullness < 100% */ /* arena_run_link_t runs100; fullness == 100% */ /* Size of regions in a run for this bin's size class. */ size_t reg_size; /* Total size of a run for this bin's size class. */ size_t run_size; /* Total number of regions in a run for this bin's size class. */ uint32_t nregs; /* Offset of first region in a run for this bin's size class. */ uint32_t reg0_offset; #ifdef MALLOC_STATS /* Bin statistics. */ malloc_bin_stats_t stats; #endif }; struct arena_s { #ifdef MALLOC_DEBUG uint32_t magic; # define ARENA_MAGIC 0x947d3d24 #endif /* All operations on this arena require that mtx be locked. */ malloc_mutex_t mtx; #ifdef MALLOC_STATS arena_stats_t stats; #endif /* * Tree of chunks this arena manages. */ arena_chunk_tree_t chunks; /* * bins is used to store rings of free regions of the following sizes, * assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS. * * bins[i] | size | * --------+------+ * 0 | 2 | * 1 | 4 | * 2 | 8 | * --------+------+ * 3 | 16 | * 4 | 32 | * 5 | 48 | * 6 | 64 | * : : * : : * 33 | 496 | * 34 | 512 | * --------+------+ * 35 | 1024 | * 36 | 2048 | * --------+------+ */ arena_bin_t bins[1]; /* Dynamically sized. */ }; /******************************************************************************/ /* * Data. */ /* Number of CPUs. */ static unsigned ncpus; /* VM page size. */ static unsigned pagesize; static unsigned pagesize_2pow; /* Various bin-related settings. */ static size_t bin_maxclass; /* Max size class for bins. */ static unsigned ntbins; /* Number of (2^n)-spaced tiny bins. */ static unsigned nqbins; /* Number of quantum-spaced bins. */ static unsigned nsbins; /* Number of (2^n)-spaced sub-page bins. */ static size_t small_min; static size_t small_max; static unsigned tiny_min_2pow; /* Various quantum-related settings. */ static size_t quantum; static size_t quantum_mask; /* (quantum - 1). */ /* Various chunk-related settings. */ static size_t chunk_size; static size_t chunk_size_mask; /* (chunk_size - 1). */ static size_t arena_maxclass; /* Max size class for arenas. */ static unsigned arena_chunk_maplen; /********/ /* * Chunks. */ /* Protects chunk-related data structures. */ static malloc_mutex_t chunks_mtx; /* Tree of chunks that are stand-alone huge allocations. */ static chunk_tree_t huge; #ifdef USE_BRK /* * Try to use brk for chunk-size allocations, due to address space constraints. */ /* * Protects sbrk() calls. This must be separate from chunks_mtx, since * base_chunk_alloc() also uses sbrk(), but cannot lock chunks_mtx (doing so * could cause recursive lock acquisition). */ static malloc_mutex_t brk_mtx; /* Result of first sbrk(0) call. */ static void *brk_base; /* Current end of brk, or ((void *)-1) if brk is exhausted. */ static void *brk_prev; /* Current upper limit on brk addresses. */ static void *brk_max; #endif #ifdef MALLOC_STATS /* * Byte counters for allocated/total space used by the chunks in the huge * allocations tree. */ static uint64_t huge_nmalloc; static uint64_t huge_ndalloc; static size_t huge_allocated; #endif /* * Tree of chunks that were previously allocated. This is used when allocating * chunks, in an attempt to re-use address space. */ static chunk_tree_t old_chunks; /****************************/ /* * base (internal allocation). */ /* * Current chunk that is being used for internal memory allocations. This * chunk is carved up in cacheline-size quanta, so that there is no chance of * false cache line sharing. */ static void *base_chunk; static void *base_next_addr; static void *base_past_addr; /* Addr immediately past base_chunk. */ static chunk_node_t *base_chunk_nodes; /* LIFO cache of chunk nodes. */ static malloc_mutex_t base_mtx; #ifdef MALLOC_STATS static uint64_t base_total; #endif /********/ /* * Arenas. */ /* * Arenas that are used to service external requests. Not all elements of the * arenas array are necessarily used; arenas are created lazily as needed. */ static arena_t **arenas; static unsigned narenas; #ifndef NO_TLS static unsigned next_arena; #endif static malloc_mutex_t arenas_mtx; /* Protects arenas initialization. */ #ifndef NO_TLS /* * Map of pthread_self() --> arenas[???], used for selecting an arena to use * for allocations. */ static __thread arena_t *arenas_map; #endif #ifdef MALLOC_STATS /* Chunk statistics. */ static chunk_stats_t stats_chunks; #endif /*******************************/ /* * Runtime configuration options. */ const char *_malloc_options; #ifndef NO_MALLOC_EXTRAS static bool opt_abort = true; static bool opt_junk = true; #else static bool opt_abort = false; static bool opt_junk = false; #endif static bool opt_hint = false; static bool opt_print_stats = false; static size_t opt_quantum_2pow = QUANTUM_2POW_MIN; static size_t opt_small_max_2pow = SMALL_MAX_2POW_DEFAULT; static size_t opt_chunk_2pow = CHUNK_2POW_DEFAULT; static bool opt_utrace = false; static bool opt_sysv = false; static bool opt_xmalloc = false; static bool opt_zero = false; static int32_t opt_narenas_lshift = 0; typedef struct { void *p; size_t s; void *r; } malloc_utrace_t; #define UTRACE(a, b, c) \ if (opt_utrace) { \ malloc_utrace_t ut = {a, b, c}; \ utrace(&ut, sizeof(ut)); \ } /******************************************************************************/ /* * Begin function prototypes for non-inline static functions. */ static void malloc_mutex_init(malloc_mutex_t *a_mutex); static void wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4); static void malloc_printf(const char *format, ...); static bool base_chunk_alloc(size_t minsize); static void *base_alloc(size_t size); static chunk_node_t *base_chunk_node_alloc(void); static void base_chunk_node_dealloc(chunk_node_t *node); #ifdef MALLOC_STATS static void stats_print(arena_t *arena); #endif static void *pages_map(void *addr, size_t size); static void pages_unmap(void *addr, size_t size); static void *chunk_alloc(size_t size); static void chunk_dealloc(void *chunk, size_t size); #ifndef NO_TLS static arena_t *choose_arena_hard(void); #endif static void arena_run_split(arena_t *arena, arena_run_t *run, bool large, size_t size); static arena_chunk_t *arena_chunk_alloc(arena_t *arena); static void arena_chunk_dealloc(arena_chunk_t *chunk); static void arena_bin_run_promote(arena_t *arena, arena_bin_t *bin, arena_run_t *run); static void arena_bin_run_demote(arena_t *arena, arena_bin_t *bin, arena_run_t *run); static arena_run_t *arena_run_alloc(arena_t *arena, bool large, size_t size); static void arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size); static arena_run_t *arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin); static void *arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin); static void *arena_malloc(arena_t *arena, size_t size); static size_t arena_salloc(const void *ptr); static void *arena_ralloc(void *ptr, size_t size, size_t oldsize); static void arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr); static bool arena_new(arena_t *arena); static arena_t *arenas_extend(unsigned ind); static void *huge_malloc(size_t size); static void *huge_ralloc(void *ptr, size_t size, size_t oldsize); static void huge_dalloc(void *ptr); static void *imalloc(size_t size); static void *ipalloc(size_t alignment, size_t size); static void *icalloc(size_t size); static size_t isalloc(const void *ptr); static void *iralloc(void *ptr, size_t size); static void idalloc(void *ptr); static void malloc_print_stats(void); static bool malloc_init_hard(void); /* * End function prototypes. */ /******************************************************************************/ /* * Begin mutex. */ static void malloc_mutex_init(malloc_mutex_t *a_mutex) { static const spinlock_t lock = _SPINLOCK_INITIALIZER; a_mutex->lock = lock; } static inline void malloc_mutex_lock(malloc_mutex_t *a_mutex) { if (__isthreaded) _SPINLOCK(&a_mutex->lock); } static inline void malloc_mutex_unlock(malloc_mutex_t *a_mutex) { if (__isthreaded) _SPINUNLOCK(&a_mutex->lock); } /* * End mutex. */ /******************************************************************************/ /* * Begin Utility functions/macros. */ /* Return the chunk address for allocation address a. */ #define CHUNK_ADDR2BASE(a) \ ((void *)((uintptr_t)(a) & ~chunk_size_mask)) /* Return the chunk offset of address a. */ #define CHUNK_ADDR2OFFSET(a) \ ((size_t)((uintptr_t)(a) & chunk_size_mask)) /* Return the smallest chunk multiple that is >= s. */ #define CHUNK_CEILING(s) \ (((s) + chunk_size_mask) & ~chunk_size_mask) /* Return the smallest cacheline multiple that is >= s. */ #define CACHELINE_CEILING(s) \ (((s) + (CACHELINE - 1)) & ~(CACHELINE - 1)) /* Return the smallest quantum multiple that is >= a. */ #define QUANTUM_CEILING(a) \ (((a) + quantum_mask) & ~quantum_mask) /* Compute the smallest power of 2 that is >= x. */ static inline size_t pow2_ceil(size_t x) { x--; x |= x >> 1; x |= x >> 2; x |= x >> 4; x |= x >> 8; x |= x >> 16; #if (SIZEOF_PTR == 8) x |= x >> 32; #endif x++; return (x); } static void wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4) { _write(STDERR_FILENO, p1, strlen(p1)); _write(STDERR_FILENO, p2, strlen(p2)); _write(STDERR_FILENO, p3, strlen(p3)); _write(STDERR_FILENO, p4, strlen(p4)); } void (*_malloc_message)(const char *p1, const char *p2, const char *p3, const char *p4) = wrtmessage; /* * Print to stderr in such a way as to (hopefully) avoid memory allocation. */ static void malloc_printf(const char *format, ...) { char buf[4096]; va_list ap; va_start(ap, format); vsnprintf(buf, sizeof(buf), format, ap); va_end(ap); _malloc_message(buf, "", "", ""); } /******************************************************************************/ static bool base_chunk_alloc(size_t minsize) { assert(minsize <= chunk_size); #ifdef USE_BRK /* * Do special brk allocation here, since the base chunk doesn't really * need to be chunk-aligned. */ if (brk_prev != (void *)-1) { void *brk_cur; intptr_t incr; malloc_mutex_lock(&brk_mtx); do { /* Get the current end of brk. */ brk_cur = sbrk(0); /* * Calculate how much padding is necessary to * chunk-align the end of brk. Don't worry about * brk_cur not being chunk-aligned though. */ incr = (intptr_t)chunk_size - (intptr_t)CHUNK_ADDR2OFFSET(brk_cur); if (incr < minsize) incr += chunk_size; brk_prev = sbrk(incr); if (brk_prev == brk_cur) { /* Success. */ malloc_mutex_unlock(&brk_mtx); base_chunk = brk_cur; base_next_addr = base_chunk; base_past_addr = (void *)((uintptr_t)base_chunk + incr); #ifdef MALLOC_STATS base_total += incr; #endif return (false); } } while (brk_prev != (void *)-1); malloc_mutex_unlock(&brk_mtx); } #endif /* * Don't worry about chunk alignment here, since base_chunk doesn't really * need to be aligned. */ base_chunk = pages_map(NULL, chunk_size); if (base_chunk == NULL) return (true); base_next_addr = base_chunk; base_past_addr = (void *)((uintptr_t)base_chunk + chunk_size); #ifdef MALLOC_STATS base_total += chunk_size; #endif return (false); } 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_chunk_alloc(csize)) { ret = NULL; goto RETURN; } } /* Allocate. */ ret = base_next_addr; base_next_addr = (void *)((uintptr_t)base_next_addr + csize); RETURN: malloc_mutex_unlock(&base_mtx); return (ret); } static chunk_node_t * base_chunk_node_alloc(void) { chunk_node_t *ret; malloc_mutex_lock(&base_mtx); if (base_chunk_nodes != NULL) { ret = base_chunk_nodes; base_chunk_nodes = *(chunk_node_t **)ret; malloc_mutex_unlock(&base_mtx); } else { malloc_mutex_unlock(&base_mtx); ret = (chunk_node_t *)base_alloc(sizeof(chunk_node_t)); } return (ret); } static void base_chunk_node_dealloc(chunk_node_t *node) { malloc_mutex_lock(&base_mtx); *(chunk_node_t **)node = base_chunk_nodes; base_chunk_nodes = node; malloc_mutex_unlock(&base_mtx); } /******************************************************************************/ #ifdef MALLOC_STATS static void stats_print(arena_t *arena) { unsigned i; int gap_start; malloc_printf("allocated: %zu\n", arena->stats.allocated); malloc_printf("calls:\n"); malloc_printf(" %12s %12s %12s\n", "nmalloc","ndalloc", "nmadvise"); malloc_printf(" %12llu %12llu %12llu\n", arena->stats.nmalloc, arena->stats.ndalloc, arena->stats.nmadvise); malloc_printf("large requests: %llu\n", arena->stats.large_nrequests); malloc_printf("bins:\n"); malloc_printf("%13s %1s %4s %5s %6s %9s %5s %6s %7s %6s %6s\n", "bin", "", "size", "nregs", "run_sz", "nrequests", "nruns", "hiruns", "curruns", "npromo", "ndemo"); for (i = 0, gap_start = -1; i < ntbins + nqbins + nsbins; i++) { if (arena->bins[i].stats.nrequests == 0) { if (gap_start == -1) gap_start = i; } else { if (gap_start != -1) { if (i > gap_start + 1) { /* Gap of more than one size class. */ malloc_printf("[%u..%u]\n", gap_start, i - 1); } else { /* Gap of one size class. */ malloc_printf("[%u]\n", gap_start); } gap_start = -1; } malloc_printf( "%13u %1s %4u %5u %6u %9llu %5llu" " %6lu %7lu %6llu %6llu\n", i, i < ntbins ? "T" : i < ntbins + nqbins ? "Q" : "S", arena->bins[i].reg_size, arena->bins[i].nregs, arena->bins[i].run_size, arena->bins[i].stats.nrequests, arena->bins[i].stats.nruns, arena->bins[i].stats.highruns, arena->bins[i].stats.curruns, arena->bins[i].stats.npromote, arena->bins[i].stats.ndemote); } } if (gap_start != -1) { if (i > gap_start + 1) { /* Gap of more than one size class. */ malloc_printf("[%u..%u]\n", gap_start, i - 1); } else { /* Gap of one size class. */ malloc_printf("[%u]\n", gap_start); } } } #endif /* * End Utility functions/macros. */ /******************************************************************************/ /* * Begin chunk management functions. */ static inline int chunk_comp(chunk_node_t *a, chunk_node_t *b) { assert(a != NULL); assert(b != NULL); if ((uintptr_t)a->chunk < (uintptr_t)b->chunk) return (-1); else if (a->chunk == b->chunk) return (0); else return (1); } /* Generate red-black tree code for chunks. */ RB_GENERATE_STATIC(chunk_tree_s, chunk_node_s, link, chunk_comp); static void * pages_map(void *addr, size_t size) { void *ret; /* * We don't use MAP_FIXED here, because it can cause the *replacement* * of existing mappings, and we only want to create new mappings. */ ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); assert(ret != NULL); if (ret == MAP_FAILED) ret = NULL; else if (addr != NULL && ret != addr) { /* * We succeeded in mapping memory, but not in the right place. */ if (munmap(ret, size) == -1) { char buf[STRERROR_BUF]; strerror_r(errno, buf, sizeof(buf)); malloc_printf("%s: (malloc) Error in munmap(): %s\n", _getprogname(), buf); if (opt_abort) abort(); } ret = NULL; } assert(ret == NULL || (addr == NULL && ret != addr) || (addr != NULL && ret == addr)); return (ret); } static void pages_unmap(void *addr, size_t size) { if (munmap(addr, size) == -1) { char buf[STRERROR_BUF]; strerror_r(errno, buf, sizeof(buf)); malloc_printf("%s: (malloc) Error in munmap(): %s\n", _getprogname(), buf); if (opt_abort) abort(); } } static void * chunk_alloc(size_t size) { void *ret, *chunk; chunk_node_t *tchunk, *delchunk; assert(size != 0); assert(size % chunk_size == 0); malloc_mutex_lock(&chunks_mtx); if (size == chunk_size) { /* * Check for address ranges that were previously chunks and try * to use them. */ tchunk = RB_MIN(chunk_tree_s, &old_chunks); while (tchunk != NULL) { /* Found an address range. Try to recycle it. */ chunk = tchunk->chunk; delchunk = tchunk; tchunk = RB_NEXT(chunk_tree_s, &old_chunks, delchunk); /* Remove delchunk from the tree. */ RB_REMOVE(chunk_tree_s, &old_chunks, delchunk); base_chunk_node_dealloc(delchunk); #ifdef USE_BRK if ((uintptr_t)chunk >= (uintptr_t)brk_base && (uintptr_t)chunk < (uintptr_t)brk_max) { /* Re-use a previously freed brk chunk. */ ret = chunk; goto RETURN; } #endif if ((ret = pages_map(chunk, size)) != NULL) { /* Success. */ goto RETURN; } } } #ifdef USE_BRK /* * Try to create allocations in brk, in order to make full use of * limited address space. */ if (brk_prev != (void *)-1) { void *brk_cur; intptr_t incr; /* * The loop is necessary to recover from races with other * threads that are using brk for something other than malloc. */ malloc_mutex_lock(&brk_mtx); do { /* Get the current end of brk. */ brk_cur = sbrk(0); /* * Calculate how much padding is necessary to * chunk-align the end of brk. */ incr = (intptr_t)size - (intptr_t)CHUNK_ADDR2OFFSET(brk_cur); if (incr == size) { ret = brk_cur; } else { ret = (void *)(intptr_t)brk_cur + incr; incr += size; } brk_prev = sbrk(incr); if (brk_prev == brk_cur) { /* Success. */ malloc_mutex_unlock(&brk_mtx); brk_max = (void *)(intptr_t)ret + size; goto RETURN; } } while (brk_prev != (void *)-1); malloc_mutex_unlock(&brk_mtx); } #endif /* * Try to over-allocate, but allow the OS to place the allocation * anywhere. Beware of size_t wrap-around. */ if (size + chunk_size > size) { if ((ret = pages_map(NULL, size + chunk_size)) != NULL) { size_t offset = CHUNK_ADDR2OFFSET(ret); /* * Success. Clean up unneeded leading/trailing space. */ if (offset != 0) { /* Leading space. */ pages_unmap(ret, chunk_size - offset); ret = (void *)((uintptr_t)ret + (chunk_size - offset)); /* Trailing space. */ pages_unmap((void *)((uintptr_t)ret + size), offset); } else { /* Trailing space only. */ pages_unmap((void *)((uintptr_t)ret + size), chunk_size); } goto RETURN; } } /* All strategies for allocation failed. */ ret = NULL; RETURN: #ifdef MALLOC_STATS if (ret != NULL) { stats_chunks.nchunks += (size / chunk_size); stats_chunks.curchunks += (size / chunk_size); } if (stats_chunks.curchunks > stats_chunks.highchunks) stats_chunks.highchunks = stats_chunks.curchunks; #endif malloc_mutex_unlock(&chunks_mtx); assert(CHUNK_ADDR2BASE(ret) == ret); return (ret); } static void chunk_dealloc(void *chunk, size_t size) { size_t offset; chunk_node_t key; chunk_node_t *node; assert(chunk != NULL); assert(CHUNK_ADDR2BASE(chunk) == chunk); assert(size != 0); assert(size % chunk_size == 0); malloc_mutex_lock(&chunks_mtx); #ifdef USE_BRK if ((uintptr_t)chunk >= (uintptr_t)brk_base && (uintptr_t)chunk < (uintptr_t)brk_max) { void *brk_cur; malloc_mutex_lock(&brk_mtx); /* Get the current end of brk. */ brk_cur = sbrk(0); /* * Try to shrink the data segment if this chunk is at the end * of the data segment. The sbrk() call here is subject to a * race condition with threads that use brk(2) or sbrk(2) * directly, but the alternative would be to leak memory for * the sake of poorly designed multi-threaded programs. */ if (brk_cur == brk_max && (void *)(uintptr_t)chunk + size == brk_max && sbrk(-(intptr_t)size) == brk_max) { malloc_mutex_unlock(&brk_mtx); if (brk_prev == brk_max) { /* Success. */ brk_prev = (void *)(intptr_t)brk_max - (intptr_t)size; brk_max = brk_prev; } goto RETURN; } else malloc_mutex_unlock(&brk_mtx); madvise(chunk, size, MADV_FREE); } else #endif pages_unmap(chunk, size); /* * Iteratively create records of each chunk-sized memory region that * 'chunk' is comprised of, so that the address range can be recycled * if memory usage increases later on. */ for (offset = 0; offset < size; offset += chunk_size) { /* * It is possible for chunk to overlap existing entries in * old_chunks if it is a huge allocation, so take care to not * leak tree nodes. */ key.chunk = (void *)((uintptr_t)chunk + (uintptr_t)offset); if (RB_FIND(chunk_tree_s, &old_chunks, &key) == NULL) { node = base_chunk_node_alloc(); if (node == NULL) break; node->chunk = key.chunk; node->size = chunk_size; RB_INSERT(chunk_tree_s, &old_chunks, node); } } #ifdef USE_BRK RETURN: #endif #ifdef MALLOC_STATS stats_chunks.curchunks -= (size / chunk_size); #endif malloc_mutex_unlock(&chunks_mtx); } /* * End chunk management functions. */ /******************************************************************************/ /* * Begin arena. */ /* * Choose an arena based on a per-thread value (fast-path code, calls slow-path * code if necessary. */ static inline arena_t * choose_arena(void) { arena_t *ret; /* * We can only use TLS if this is a PIC library, since for the static * library version, libc's malloc is used by TLS allocation, which * introduces a bootstrapping issue. */ #ifndef NO_TLS if (__isthreaded == false) { /* * Avoid the overhead of TLS for single-threaded operation. If the * app switches to threaded mode, the initial thread may end up * being assigned to some other arena, but this one-time switch * shouldn't cause significant issues. * */ return (arenas[0]); } ret = arenas_map; if (ret == NULL) ret = choose_arena_hard(); #else if (__isthreaded) { unsigned long ind; /* * Hash _pthread_self() to one of the arenas. There is a prime * number of arenas, so this has a reasonable chance of * working. Even so, the hashing can be easily thwarted by * inconvenient _pthread_self() values. Without specific * knowledge of how _pthread_self() calculates values, we can't * easily do much better than this. */ ind = (unsigned long) _pthread_self() % narenas; /* * Optimistially assume that arenas[ind] has been initialized. * At worst, we find out that some other thread has already * done so, after acquiring the lock in preparation. Note that * this lazy locking also has the effect of lazily forcing * cache coherency; without the lock acquisition, there's no * guarantee that modification of arenas[ind] by another thread * would be seen on this CPU for an arbitrary amount of time. * * In general, this approach to modifying a synchronized value * isn't a good idea, but in this case we only ever modify the * value once, so things work out well. */ ret = arenas[ind]; if (ret == NULL) { /* * Avoid races with another thread that may have already * initialized arenas[ind]. */ malloc_mutex_lock(&arenas_mtx); if (arenas[ind] == NULL) ret = arenas_extend((unsigned)ind); else ret = arenas[ind]; malloc_mutex_unlock(&arenas_mtx); } } else ret = arenas[0]; #endif assert(ret != NULL); return (ret); } #ifndef NO_TLS /* * Choose an arena based on a per-thread value (slow-path code only, called * only by choose_arena()). */ static arena_t * choose_arena_hard(void) { arena_t *ret; assert(__isthreaded); /* Assign one of the arenas to this thread, in a round-robin fashion. */ malloc_mutex_lock(&arenas_mtx); ret = arenas[next_arena]; if (ret == NULL) ret = arenas_extend(next_arena); if (ret == NULL) { /* * Make sure that this function never returns NULL, so that * choose_arena() doesn't have to check for a NULL return * value. */ ret = arenas[0]; } next_arena = (next_arena + 1) % narenas; malloc_mutex_unlock(&arenas_mtx); arenas_map = ret; return (ret); } #endif static inline int arena_chunk_comp(arena_chunk_t *a, arena_chunk_t *b) { assert(a != NULL); assert(b != NULL); if ((uintptr_t)a < (uintptr_t)b) return (-1); else if (a == b) return (0); else return (1); } /* Generate red-black tree code for arena chunks. */ RB_GENERATE_STATIC(arena_chunk_tree_s, arena_chunk_s, link, arena_chunk_comp); static inline void * arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin) { void *ret; unsigned i, mask, bit, regind; assert(run->magic == ARENA_RUN_MAGIC); for (i = run->regs_minelm; i < REGS_MASK_NELMS; i++) { mask = run->regs_mask[i]; if (mask != 0) { /* Usable allocation found. */ bit = ffs(mask) - 1; regind = ((i << (SIZEOF_INT_2POW + 3)) + bit); ret = (void *)&((char *)run)[bin->reg0_offset + (bin->reg_size * regind)]; /* Clear bit. */ mask ^= (1 << bit); run->regs_mask[i] = mask; return (ret); } else { /* * Make a note that nothing before this element * contains a free region. */ run->regs_minelm = i + 1; } } /* Not reached. */ assert(0); return (NULL); } static inline void arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size) { /* * 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) (((1 << SIZE_INV_SHIFT) / (s << QUANTUM_2POW_MIN)) + 1) static const unsigned size_invs[] = { SIZE_INV(3), SIZE_INV(4), SIZE_INV(5), SIZE_INV(6), SIZE_INV(7), SIZE_INV(8), SIZE_INV(9), SIZE_INV(10), SIZE_INV(11), SIZE_INV(12),SIZE_INV(13), SIZE_INV(14), SIZE_INV(15), SIZE_INV(16),SIZE_INV(17), SIZE_INV(18), SIZE_INV(19), SIZE_INV(20),SIZE_INV(21), SIZE_INV(22), SIZE_INV(23), SIZE_INV(24),SIZE_INV(25), SIZE_INV(26), SIZE_INV(27), SIZE_INV(28),SIZE_INV(29), SIZE_INV(30), SIZE_INV(31) #if (QUANTUM_2POW_MIN < 4) , SIZE_INV(32), SIZE_INV(33), SIZE_INV(34), SIZE_INV(35), SIZE_INV(36), SIZE_INV(37), SIZE_INV(38), SIZE_INV(39), SIZE_INV(40), SIZE_INV(41), SIZE_INV(42), SIZE_INV(43), SIZE_INV(44), SIZE_INV(45), SIZE_INV(46), SIZE_INV(47), SIZE_INV(48), SIZE_INV(49), SIZE_INV(50), SIZE_INV(51), SIZE_INV(52), SIZE_INV(53), SIZE_INV(54), SIZE_INV(55), SIZE_INV(56), SIZE_INV(57), SIZE_INV(58), SIZE_INV(59), SIZE_INV(60), SIZE_INV(61), SIZE_INV(62), SIZE_INV(63) #endif }; unsigned diff, regind, elm, bit; assert(run->magic == ARENA_RUN_MAGIC); assert(((sizeof(size_invs)) / sizeof(unsigned)) + 3 >= (SMALL_MAX_DEFAULT >> QUANTUM_2POW_MIN)); /* * Avoid doing division with a variable divisor if possible. Using * actual division here can reduce allocator throughput by over 20%! */ diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run - bin->reg0_offset); if ((size & (size - 1)) == 0) { /* * log2_table allows fast division of a power of two in the * [1..128] range. * * (x / divisor) becomes (x >> log2_table[divisor - 1]). */ static const unsigned char log2_table[] = { 0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7 }; if (size <= 128) regind = (diff >> log2_table[size - 1]); else if (size <= 32768) regind = diff >> (8 + log2_table[(size >> 8) - 1]); else { /* * The page size is too large for us to use the lookup * table. Use real division. */ regind = diff / size; } } else if (size <= ((sizeof(size_invs) / sizeof(unsigned)) << QUANTUM_2POW_MIN) + 2) { regind = size_invs[(size >> QUANTUM_2POW_MIN) - 3] * diff; regind >>= SIZE_INV_SHIFT; } else { /* * size_invs isn't large enough to handle this size class, so * calculate regind using actual division. This only happens * if the user increases small_max via the 'S' runtime * configuration option. */ regind = diff / size; }; assert(diff == regind * size); assert(regind < bin->nregs); elm = regind >> (SIZEOF_INT_2POW + 3); if (elm < run->regs_minelm) run->regs_minelm = elm; bit = regind - (elm << (SIZEOF_INT_2POW + 3)); assert((run->regs_mask[elm] & (1 << bit)) == 0); run->regs_mask[elm] |= (1 << bit); #undef SIZE_INV #undef SIZE_INV_SHIFT } static void arena_run_split(arena_t *arena, arena_run_t *run, bool large, size_t size) { arena_chunk_t *chunk; unsigned run_ind, map_offset, total_pages, need_pages; unsigned i, log2_run_pages, run_pages; chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run); run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow); assert(chunk->map[run_ind].free); total_pages = chunk->map[run_ind].npages; need_pages = (size >> pagesize_2pow); assert(chunk->map[run_ind].free); assert(chunk->map[run_ind].large == false); assert(chunk->map[run_ind].npages == total_pages); /* Split enough pages from the front of run to fit allocation size. */ map_offset = run_ind; for (i = 0; i < need_pages; i++) { chunk->map[map_offset + i].free = false; chunk->map[map_offset + i].large = large; chunk->map[map_offset + i].npages = need_pages; chunk->map[map_offset + i].pos = i; } /* Update map for trailing pages. */ map_offset += need_pages; while (map_offset < run_ind + total_pages) { log2_run_pages = ffs(map_offset) - 1; run_pages = (1 << log2_run_pages); chunk->map[map_offset].free = true; chunk->map[map_offset].large = false; chunk->map[map_offset].npages = run_pages; chunk->nfree_runs[log2_run_pages]++; map_offset += run_pages; } chunk->pages_used += (size >> pagesize_2pow); } static arena_chunk_t * arena_chunk_alloc(arena_t *arena) { arena_chunk_t *chunk; unsigned i, j, header_npages, pow2_header_npages, map_offset; unsigned log2_run_pages, run_pages; size_t header_size; chunk = (arena_chunk_t *)chunk_alloc(chunk_size); if (chunk == NULL) return (NULL); chunk->arena = arena; RB_INSERT(arena_chunk_tree_s, &arena->chunks, chunk); /* * Claim that no pages are in use, since the header is merely overhead. */ chunk->pages_used = 0; memset(&chunk->nfree_runs, 0, sizeof(chunk->nfree_runs)); header_size = (size_t)((uintptr_t)&chunk->map[arena_chunk_maplen] - (uintptr_t)chunk); if (header_size % pagesize != 0) { /* Round up to the nearest page boundary. */ header_size += pagesize - (header_size % pagesize); } header_npages = header_size >> pagesize_2pow; pow2_header_npages = pow2_ceil(header_npages); /* * Iteratively mark runs as in use, until we've spoken for the entire * header. */ map_offset = 0; for (i = 0; header_npages > 0; i++) { if ((pow2_header_npages >> i) <= header_npages) { for (j = 0; j < (pow2_header_npages >> i); j++) { chunk->map[map_offset + j].free = false; chunk->map[map_offset + j].large = false; chunk->map[map_offset + j].npages = (pow2_header_npages >> i); chunk->map[map_offset + j].pos = j; } header_npages -= (pow2_header_npages >> i); map_offset += (pow2_header_npages >> i); } } /* * Finish initializing map. The chunk header takes up some space at * the beginning of the chunk, which we just took care of by * "allocating" the leading pages. */ while (map_offset < (chunk_size >> pagesize_2pow)) { log2_run_pages = ffs(map_offset) - 1; run_pages = (1 << log2_run_pages); chunk->map[map_offset].free = true; chunk->map[map_offset].large = false; chunk->map[map_offset].npages = run_pages; chunk->nfree_runs[log2_run_pages]++; map_offset += run_pages; } return (chunk); } static void arena_chunk_dealloc(arena_chunk_t *chunk) { RB_REMOVE(arena_chunk_tree_s, &chunk->arena->chunks, chunk); chunk_dealloc((void *)chunk, chunk_size); } static void arena_bin_run_promote(arena_t *arena, arena_bin_t *bin, arena_run_t *run) { assert(bin == run->bin); /* Promote. */ assert(run->free_min > run->nfree); assert(run->quartile < RUN_Q100); run->quartile++; #ifdef MALLOC_STATS bin->stats.npromote++; #endif /* Re-file run. */ switch (run->quartile) { case RUN_QINIT: assert(0); break; case RUN_Q0: qr_before_insert((arena_run_t *)&bin->runs0, run, link); run->free_max = bin->nregs - 1; run->free_min = (bin->nregs >> 1) + 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q25: qr_remove(run, link); qr_before_insert((arena_run_t *)&bin->runs25, run, link); run->free_max = ((bin->nregs >> 2) * 3) - 1; run->free_min = (bin->nregs >> 2) + 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q50: qr_remove(run, link); qr_before_insert((arena_run_t *)&bin->runs50, run, link); run->free_max = (bin->nregs >> 1) - 1; run->free_min = 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q75: /* * Skip RUN_Q75 during promotion from RUN_Q50. * Separate handling of RUN_Q75 and RUN_Q100 allows us * to keep completely full runs in RUN_Q100, thus * guaranteeing that runs in RUN_Q75 are only mostly * full. This provides a method for avoiding a linear * search for non-full runs, which avoids some * pathological edge cases. */ run->quartile++; /* Fall through. */ case RUN_Q100: qr_remove(run, link); assert(bin->runcur == run); bin->runcur = NULL; run->free_max = 0; run->free_min = 0; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; default: assert(0); break; } } static void arena_bin_run_demote(arena_t *arena, arena_bin_t *bin, arena_run_t *run) { assert(bin == run->bin); /* Demote. */ assert(run->free_max < run->nfree); assert(run->quartile > RUN_QINIT); run->quartile--; #ifdef MALLOC_STATS bin->stats.ndemote++; #endif /* Re-file run. */ switch (run->quartile) { case RUN_QINIT: qr_remove(run, link); #ifdef MALLOC_STATS bin->stats.curruns--; #endif if (bin->runcur == run) bin->runcur = NULL; #ifdef MALLOC_DEBUG run->magic = 0; #endif arena_run_dalloc(arena, run, bin->run_size); break; case RUN_Q0: qr_remove(run, link); qr_before_insert((arena_run_t *)&bin->runs0, run, link); run->free_max = bin->nregs - 1; run->free_min = (bin->nregs >> 1) + 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q25: qr_remove(run, link); qr_before_insert((arena_run_t *)&bin->runs25, run, link); run->free_max = ((bin->nregs >> 2) * 3) - 1; run->free_min = (bin->nregs >> 2) + 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q50: qr_remove(run, link); qr_before_insert((arena_run_t *)&bin->runs50, run, link); run->free_max = (bin->nregs >> 1) - 1; run->free_min = 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q75: qr_before_insert((arena_run_t *)&bin->runs75, run, link); run->free_max = (bin->nregs >> 2) - 1; run->free_min = 1; assert(run->nfree <= run->free_max); assert(run->nfree >= run->free_min); break; case RUN_Q100: default: assert(0); break; } } static arena_run_t * arena_run_alloc(arena_t *arena, bool large, size_t size) { arena_run_t *run; unsigned min_ind, i, j; arena_chunk_t *chunk; #ifndef NDEBUG int rep = 0; #endif assert(size <= arena_maxclass); AGAIN: #ifndef NDEBUG rep++; assert(rep <= 2); #endif /* * Search through arena's chunks in address order for a run that is * large enough. Look for a precise fit, but do not pass up a chunk * that has a run which is large enough to split. */ min_ind = ffs(size >> pagesize_2pow) - 1; RB_FOREACH(chunk, arena_chunk_tree_s, &arena->chunks) { for (i = min_ind; i < (opt_chunk_2pow - pagesize_2pow); i++) { if (chunk->nfree_runs[i] > 0) { arena_chunk_map_t *map = chunk->map; /* Scan chunk's map for free run. */ for (j = 0; j < arena_chunk_maplen; j += map[j].npages) { if (map[j].free && map[j].npages == (1 << i)) {/*<----------------------------*/ run = (arena_run_t *)&((char *)chunk)[j << pagesize_2pow]; assert(chunk->nfree_runs[i] > 0); chunk->nfree_runs[i]--; /* Update page map. */ arena_run_split(arena, run, large, size); return (run); }/*---------------------------->*/ } /* Not reached. */ assert(0); } } } /* No usable runs. Allocate a new chunk, then try again. */ if (arena_chunk_alloc(arena) == NULL) return (NULL); goto AGAIN; } static void arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size) { arena_chunk_t *chunk; unsigned run_ind, buddy_ind, base_run_ind, run_pages, log2_run_pages; chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run); run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow); run_pages = (size >> pagesize_2pow); log2_run_pages = ffs(run_pages) - 1; assert(run_pages > 0); /* Subtract pages from count of pages used in chunk. */ chunk->pages_used -= run_pages; /* Mark run as deallocated. */ chunk->map[run_ind].free = true; chunk->map[run_ind].large = false; chunk->map[run_ind].npages = run_pages; /* * Tell the kernel that we don't need the data in this run, but only if * requested via runtime configuration. */ if (opt_hint) { madvise(run, size, MADV_FREE); #ifdef MALLOC_STATS arena->stats.nmadvise += (size >> pagesize_2pow); #endif } /* * Iteratively coalesce with buddies. Conceptually, the buddy scheme * induces a tree on the set of pages. If we know the number of pages * in the subtree rooted at the current node, we can quickly determine * whether a run is the left or right buddy, and then calculate the * buddy's index. */ for (; (run_pages = (1 << log2_run_pages)) < arena_chunk_maplen; log2_run_pages++) { if (((run_ind >> log2_run_pages) & 1) == 0) { /* Current run precedes its buddy. */ buddy_ind = run_ind + run_pages; base_run_ind = run_ind; } else { /* Current run follows its buddy. */ buddy_ind = run_ind - run_pages; base_run_ind = buddy_ind; } if (chunk->map[buddy_ind].free == false || chunk->map[buddy_ind].npages != run_pages) break; assert(chunk->nfree_runs[log2_run_pages] > 0); chunk->nfree_runs[log2_run_pages]--; /* Coalesce. */ chunk->map[base_run_ind].npages = (run_pages << 1); /* Update run_ind to be the beginning of the coalesced run. */ run_ind = base_run_ind; } chunk->nfree_runs[log2_run_pages]++; /* Free pages, to the extent possible. */ if (chunk->pages_used == 0) { /* This chunk is completely unused now, so deallocate it. */ arena_chunk_dealloc(chunk); } } static arena_run_t * arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin) { arena_run_t *run; unsigned i, remainder; /* Look for a usable run. */ if ((run = qr_next((arena_run_t *)&bin->runs50, link)) != (arena_run_t *)&bin->runs50 || (run = qr_next((arena_run_t *)&bin->runs25, link)) != (arena_run_t *)&bin->runs25 || (run = qr_next((arena_run_t *)&bin->runs0, link)) != (arena_run_t *)&bin->runs0 || (run = qr_next((arena_run_t *)&bin->runs75, link)) != (arena_run_t *)&bin->runs75) { /* run is guaranteed to have available space. */ qr_remove(run, link); return (run); } /* No existing runs have any space available. */ /* Allocate a new run. */ run = arena_run_alloc(arena, false, bin->run_size); if (run == NULL) return (NULL); /* Initialize run internals. */ qr_new(run, link); run->bin = bin; for (i = 0; i < (bin->nregs >> (SIZEOF_INT_2POW + 3)); i++) run->regs_mask[i] = UINT_MAX; remainder = bin->nregs % (1 << (SIZEOF_INT_2POW + 3)); if (remainder != 0) { run->regs_mask[i] = (UINT_MAX >> ((1 << (SIZEOF_INT_2POW + 3)) - remainder)); i++; } for (; i < REGS_MASK_NELMS; i++) run->regs_mask[i] = 0; run->regs_minelm = 0; run->nfree = bin->nregs; run->quartile = RUN_QINIT; run->free_max = bin->nregs; run->free_min = ((bin->nregs >> 2) * 3) + 1; #ifdef MALLOC_DEBUG run->magic = ARENA_RUN_MAGIC; #endif #ifdef MALLOC_STATS bin->stats.nruns++; bin->stats.curruns++; if (bin->stats.curruns > bin->stats.highruns) bin->stats.highruns = bin->stats.curruns; #endif return (run); } /* bin->runcur must have space available before this function is called. */ static inline void * arena_bin_malloc_easy(arena_t *arena, arena_bin_t *bin, arena_run_t *run) { void *ret; assert(run->magic == ARENA_RUN_MAGIC); assert(run->nfree > 0); ret = arena_run_reg_alloc(run, bin); assert(ret != NULL); run->nfree--; if (run->nfree < run->free_min) { /* Promote run to higher fullness quartile. */ arena_bin_run_promote(arena, bin, run); } 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) { assert(bin->runcur == NULL || bin->runcur->quartile == RUN_Q100); 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)); } static void * arena_malloc(arena_t *arena, size_t size) { void *ret; assert(arena != NULL); assert(arena->magic == ARENA_MAGIC); assert(size != 0); assert(QUANTUM_CEILING(size) <= arena_maxclass); if (size <= bin_maxclass) { arena_bin_t *bin; arena_run_t *run; /* Small allocation. */ if (size < small_min) { /* Tiny. */ size = pow2_ceil(size); bin = &arena->bins[ffs(size >> (tiny_min_2pow + 1))]; #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 < (1 << tiny_min_2pow)) size = (1 << tiny_min_2pow); #endif } else if (size <= small_max) { /* Quantum-spaced. */ size = QUANTUM_CEILING(size); bin = &arena->bins[ntbins + (size >> opt_quantum_2pow) - 1]; } else { /* Sub-page. */ size = pow2_ceil(size); bin = &arena->bins[ntbins + nqbins + (ffs(size >> opt_small_max_2pow) - 2)]; } assert(size == bin->reg_size); malloc_mutex_lock(&arena->mtx); if ((run = bin->runcur) != NULL) ret = arena_bin_malloc_easy(arena, bin, run); else ret = arena_bin_malloc_hard(arena, bin); #ifdef MALLOC_STATS bin->stats.nrequests++; #endif } else { /* Medium allocation. */ size = pow2_ceil(size); malloc_mutex_lock(&arena->mtx); ret = (void *)arena_run_alloc(arena, true, size); #ifdef MALLOC_STATS arena->stats.large_nrequests++; #endif } #ifdef MALLOC_STATS arena->stats.nmalloc++; if (ret != NULL) arena->stats.allocated += size; #endif malloc_mutex_unlock(&arena->mtx); if (opt_junk && ret != NULL) memset(ret, 0xa5, size); else if (opt_zero && ret != NULL) memset(ret, 0, size); return (ret); } /* Return the size of the allocation pointed to by ptr. */ static size_t arena_salloc(const void *ptr) { size_t ret; arena_chunk_t *chunk; uint32_t pageind; arena_chunk_map_t mapelm; assert(ptr != NULL); assert(CHUNK_ADDR2BASE(ptr) != ptr); /* * No arena data structures that we query here can change in a way that * affects this function, so we don't need to lock. */ chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow); mapelm = chunk->map[pageind]; assert(mapelm.free == false); if (mapelm.large == false) { arena_run_t *run; pageind -= mapelm.pos; run = (arena_run_t *)&((char *)chunk)[pageind << pagesize_2pow]; assert(run->magic == ARENA_RUN_MAGIC); ret = run->bin->reg_size; } else ret = mapelm.npages << pagesize_2pow; return (ret); } static void * arena_ralloc(void *ptr, size_t size, size_t oldsize) { void *ret; /* Avoid moving the allocation if the size class would not change. */ if (size < small_min) { if (oldsize < small_min && ffs(pow2_ceil(size) >> (tiny_min_2pow + 1)) == ffs(pow2_ceil(oldsize) >> (tiny_min_2pow + 1))) goto IN_PLACE; } else if (size <= small_max) { if (oldsize >= small_min && oldsize <= small_max && (QUANTUM_CEILING(size) >> opt_quantum_2pow) == (QUANTUM_CEILING(oldsize) >> opt_quantum_2pow)) goto IN_PLACE; } else { if (oldsize > small_max && pow2_ceil(size) == oldsize) goto IN_PLACE; } /* * If we get here, then size and oldsize are different enough that we * need to use a different size class. In that case, fall back to * allocating new space and copying. */ ret = arena_malloc(choose_arena(), size); if (ret == NULL) return (NULL); if (size < oldsize) memcpy(ret, ptr, size); else memcpy(ret, ptr, oldsize); idalloc(ptr); return (ret); IN_PLACE: if (opt_junk && size < oldsize) memset(&((char *)ptr)[size], 0x5a, oldsize - size); else if (opt_zero && size > oldsize) memset(&((char *)ptr)[size], 0, size - oldsize); return (ptr); } static void arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr) { unsigned pageind; arena_chunk_map_t mapelm; size_t size; assert(arena != NULL); assert(arena->magic == ARENA_MAGIC); assert(chunk->arena == arena); assert(ptr != NULL); assert(CHUNK_ADDR2BASE(ptr) != ptr); pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow); mapelm = chunk->map[pageind]; assert(mapelm.free == false); if (mapelm.large == false) { arena_run_t *run; arena_bin_t *bin; /* Small allocation. */ pageind -= mapelm.pos; run = (arena_run_t *)&((char *)chunk)[pageind << pagesize_2pow]; assert(run->magic == ARENA_RUN_MAGIC); bin = run->bin; size = bin->reg_size; if (opt_junk) memset(ptr, 0x5a, size); malloc_mutex_lock(&arena->mtx); arena_run_reg_dalloc(run, bin, ptr, size); run->nfree++; if (run->nfree > run->free_max) { /* Demote run to lower fullness quartile. */ arena_bin_run_demote(arena, bin, run); } } else { /* Medium allocation. */ size = mapelm.npages << pagesize_2pow; assert((((uintptr_t)ptr) & (size - 1)) == 0); if (opt_junk) memset(ptr, 0x5a, size); malloc_mutex_lock(&arena->mtx); arena_run_dalloc(arena, (arena_run_t *)ptr, size); } #ifdef MALLOC_STATS arena->stats.allocated -= size; #endif malloc_mutex_unlock(&arena->mtx); } static bool arena_new(arena_t *arena) { unsigned i; arena_bin_t *bin; size_t pow2_size, run_size; malloc_mutex_init(&arena->mtx); #ifdef MALLOC_STATS memset(&arena->stats, 0, sizeof(arena_stats_t)); #endif /* Initialize chunks. */ RB_INIT(&arena->chunks); /* Initialize bins. */ /* (2^n)-spaced tiny bins. */ for (i = 0; i < ntbins; i++) { bin = &arena->bins[i]; bin->runcur = NULL; qr_new((arena_run_t *)&bin->runs0, link); qr_new((arena_run_t *)&bin->runs25, link); qr_new((arena_run_t *)&bin->runs50, link); qr_new((arena_run_t *)&bin->runs75, link); bin->reg_size = (1 << (tiny_min_2pow + i)); /* * Calculate how large of a run to allocate. Make sure that at * least RUN_MIN_REGS regions fit in the run. */ run_size = bin->reg_size << RUN_MIN_REGS_2POW; if (run_size < pagesize) run_size = pagesize; if (run_size > (pagesize << RUN_MAX_PAGES_2POW)) run_size = (pagesize << RUN_MAX_PAGES_2POW); if (run_size > arena_maxclass) run_size = arena_maxclass; bin->run_size = run_size; assert(run_size >= sizeof(arena_run_t)); bin->nregs = (run_size - sizeof(arena_run_t)) / bin->reg_size; if (bin->nregs > (REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3))) { /* Take care not to overflow regs_mask. */ bin->nregs = REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3); } bin->reg0_offset = run_size - (bin->nregs * bin->reg_size); #ifdef MALLOC_STATS memset(&bin->stats, 0, sizeof(malloc_bin_stats_t)); #endif } /* Quantum-spaced bins. */ for (; i < ntbins + nqbins; i++) { bin = &arena->bins[i]; bin->runcur = NULL; qr_new((arena_run_t *)&bin->runs0, link); qr_new((arena_run_t *)&bin->runs25, link); qr_new((arena_run_t *)&bin->runs50, link); qr_new((arena_run_t *)&bin->runs75, link); bin->reg_size = quantum * (i - ntbins + 1); /* * Calculate how large of a run to allocate. Make sure that at * least RUN_MIN_REGS regions fit in the run. */ pow2_size = pow2_ceil(quantum * (i - ntbins + 1)); run_size = (pow2_size << RUN_MIN_REGS_2POW); if (run_size < pagesize) run_size = pagesize; if (run_size > (pagesize << RUN_MAX_PAGES_2POW)) run_size = (pagesize << RUN_MAX_PAGES_2POW); if (run_size > arena_maxclass) run_size = arena_maxclass; bin->run_size = run_size; bin->nregs = (run_size - sizeof(arena_run_t)) / bin->reg_size; assert(bin->nregs <= REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3)); bin->reg0_offset = run_size - (bin->nregs * bin->reg_size); #ifdef MALLOC_STATS memset(&bin->stats, 0, sizeof(malloc_bin_stats_t)); #endif } /* (2^n)-spaced sub-page bins. */ for (; i < ntbins + nqbins + nsbins; i++) { bin = &arena->bins[i]; bin->runcur = NULL; qr_new((arena_run_t *)&bin->runs0, link); qr_new((arena_run_t *)&bin->runs25, link); qr_new((arena_run_t *)&bin->runs50, link); qr_new((arena_run_t *)&bin->runs75, link); bin->reg_size = (small_max << (i - (ntbins + nqbins) + 1)); /* * Calculate how large of a run to allocate. Make sure that at * least RUN_MIN_REGS regions fit in the run. */ run_size = bin->reg_size << RUN_MIN_REGS_2POW; if (run_size < pagesize) run_size = pagesize; if (run_size > (pagesize << RUN_MAX_PAGES_2POW)) run_size = (pagesize << RUN_MAX_PAGES_2POW); if (run_size > arena_maxclass) run_size = arena_maxclass; bin->run_size = run_size; bin->nregs = (run_size - sizeof(arena_run_t)) / bin->reg_size; assert(bin->nregs <= REGS_MASK_NELMS << (SIZEOF_INT_2POW + 3)); bin->reg0_offset = run_size - (bin->nregs * bin->reg_size); #ifdef MALLOC_STATS memset(&bin->stats, 0, sizeof(malloc_bin_stats_t)); #endif } #ifdef MALLOC_DEBUG arena->magic = ARENA_MAGIC; #endif return (false); } /* Create a new arena and insert it into the arenas array at index ind. */ static arena_t * arenas_extend(unsigned ind) { arena_t *ret; /* Allocate enough space for trailing bins. */ ret = (arena_t *)base_alloc(sizeof(arena_t) + (sizeof(arena_bin_t) * (ntbins + nqbins + nsbins - 1))); if (ret != NULL && arena_new(ret) == false) { arenas[ind] = ret; return (ret); } /* Only reached if there is an OOM error. */ /* * OOM here is quite inconvenient to propagate, since dealing with it * would require a check for failure in the fast path. Instead, punt * by using arenas[0]. In practice, this is an extremely unlikely * failure. */ malloc_printf("%s: (malloc) Error initializing arena\n", _getprogname()); if (opt_abort) abort(); return (arenas[0]); } /* * End arena. */ /******************************************************************************/ /* * Begin general internal functions. */ static void * huge_malloc(size_t size) { void *ret; size_t csize; chunk_node_t *node; /* Allocate one or more contiguous chunks for this request. */ csize = CHUNK_CEILING(size); if (csize == 0) { /* size is large enough to cause size_t wrap-around. */ return (NULL); } /* Allocate a chunk node with which to track the chunk. */ node = base_chunk_node_alloc(); if (node == NULL) return (NULL); ret = chunk_alloc(csize); if (ret == NULL) { base_chunk_node_dealloc(node); return (NULL); } /* Insert node into huge. */ node->chunk = ret; node->size = csize; malloc_mutex_lock(&chunks_mtx); RB_INSERT(chunk_tree_s, &huge, node); #ifdef MALLOC_STATS huge_nmalloc++; huge_allocated += csize; #endif malloc_mutex_unlock(&chunks_mtx); if (opt_junk && ret != NULL) memset(ret, 0xa5, csize); else if (opt_zero && ret != NULL) memset(ret, 0, csize); return (ret); } static void * huge_ralloc(void *ptr, size_t size, size_t oldsize) { void *ret; /* Avoid moving the allocation if the size class would not change. */ if (oldsize > arena_maxclass && CHUNK_CEILING(size) == CHUNK_CEILING(oldsize)) return (ptr); /* * If we get here, then size and oldsize are different enough that we * need to use a different size class. In that case, fall back to * allocating new space and copying. */ ret = huge_malloc(size); if (ret == NULL) return (NULL); if (CHUNK_ADDR2BASE(ptr) == ptr) { /* The old allocation is a chunk. */ if (size < oldsize) memcpy(ret, ptr, size); else memcpy(ret, ptr, oldsize); } else { /* The old allocation is a region. */ assert(oldsize < size); memcpy(ret, ptr, oldsize); } idalloc(ptr); return (ret); } static void huge_dalloc(void *ptr) { chunk_node_t key; chunk_node_t *node; malloc_mutex_lock(&chunks_mtx); /* Extract from tree of huge allocations. */ key.chunk = ptr; node = RB_FIND(chunk_tree_s, &huge, &key); assert(node != NULL); assert(node->chunk == ptr); RB_REMOVE(chunk_tree_s, &huge, node); #ifdef MALLOC_STATS /* Update counters. */ huge_ndalloc++; huge_allocated -= node->size; #endif malloc_mutex_unlock(&chunks_mtx); /* Unmap chunk. */ #ifdef USE_BRK if (opt_junk) memset(node->chunk, 0x5a, node->size); #endif chunk_dealloc(node->chunk, node->size); base_chunk_node_dealloc(node); } static void * imalloc(size_t size) { void *ret; assert(size != 0); if (size <= arena_maxclass) ret = arena_malloc(choose_arena(), size); else ret = huge_malloc(size); return (ret); } static void * ipalloc(size_t alignment, size_t size) { void *ret; size_t alloc_size; /* * Take advantage of the fact that for each 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. */ alloc_size = (size + (alignment - 1)) & (-alignment); if (alloc_size < size) { /* size_t overflow. */ return (NULL); } if (alloc_size <= arena_maxclass) ret = arena_malloc(choose_arena(), alloc_size); else { if (alignment <= chunk_size) ret = huge_malloc(size); else { size_t chunksize, offset; chunk_node_t *node; /* * This allocation requires alignment that is even * larger than chunk alignment. This means that * huge_malloc() isn't good enough. * * Allocate almost twice as many chunks as are demanded * by the size or alignment, in order to assure the * alignment can be achieved, then unmap leading and * trailing chunks. */ chunksize = CHUNK_CEILING(size); if (size >= alignment) alloc_size = chunksize + alignment - chunk_size; else alloc_size = (alignment << 1) - chunk_size; /* * Allocate a chunk node with which to track the chunk. */ node = base_chunk_node_alloc(); if (node == NULL) return (NULL); ret = chunk_alloc(alloc_size); if (ret == NULL) { base_chunk_node_dealloc(node); return (NULL); } offset = (uintptr_t)ret & (alignment - 1); assert(offset % chunk_size == 0); assert(offset < alloc_size); if (offset == 0) { /* Trim trailing space. */ chunk_dealloc((void *)((uintptr_t)ret + chunksize), alloc_size - chunksize); } else { size_t trailsize; /* Trim leading space. */ chunk_dealloc(ret, alignment - offset); ret = (void *)((uintptr_t)ret + (alignment - offset)); trailsize = alloc_size - (alignment - offset) - chunksize; if (trailsize != 0) { /* Trim trailing space. */ assert(trailsize < alloc_size); chunk_dealloc((void *)((uintptr_t)ret + chunksize), trailsize); } } /* Insert node into huge. */ node->chunk = ret; node->size = chunksize; malloc_mutex_lock(&chunks_mtx); RB_INSERT(chunk_tree_s, &huge, node); #ifdef MALLOC_STATS huge_allocated += size; #endif malloc_mutex_unlock(&chunks_mtx); if (opt_junk) memset(ret, 0xa5, chunksize); else if (opt_zero) memset(ret, 0, chunksize); } } assert(((uintptr_t)ret & (alignment - 1)) == 0); return (ret); } static void * icalloc(size_t size) { void *ret; if (size <= arena_maxclass) { ret = arena_malloc(choose_arena(), size); if (ret == NULL) return (NULL); memset(ret, 0, size); } else { /* * The virtual memory system provides zero-filled pages, so * there is no need to do so manually, unless opt_junk is * enabled, in which case huge_malloc() fills huge allocations * with junk. */ ret = huge_malloc(size); if (ret == NULL) return (NULL); if (opt_junk) memset(ret, 0, size); #ifdef USE_BRK else if ((uintptr_t)ret >= (uintptr_t)brk_base && (uintptr_t)ret < (uintptr_t)brk_max) { /* * This may be a re-used brk chunk. Therefore, zero * the memory. */ memset(ret, 0, size); } #endif } return (ret); } static size_t isalloc(const void *ptr) { size_t ret; arena_chunk_t *chunk; assert(ptr != NULL); chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); if (chunk != ptr) { /* Region. */ assert(chunk->arena->magic == ARENA_MAGIC); ret = arena_salloc(ptr); } else { chunk_node_t *node, key; /* Chunk (huge allocation). */ malloc_mutex_lock(&chunks_mtx); /* Extract from tree of huge allocations. */ key.chunk = (void *)ptr; node = RB_FIND(chunk_tree_s, &huge, &key); assert(node != NULL); ret = node->size; malloc_mutex_unlock(&chunks_mtx); } return (ret); } static void * iralloc(void *ptr, size_t size) { void *ret; size_t oldsize; assert(ptr != NULL); assert(size != 0); oldsize = isalloc(ptr); if (size <= arena_maxclass) ret = arena_ralloc(ptr, size, oldsize); else ret = huge_ralloc(ptr, size, oldsize); return (ret); } static void idalloc(void *ptr) { arena_chunk_t *chunk; assert(ptr != NULL); chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); if (chunk != ptr) { /* Region. */ #ifdef MALLOC_STATS malloc_mutex_lock(&chunk->arena->mtx); chunk->arena->stats.ndalloc++; malloc_mutex_unlock(&chunk->arena->mtx); #endif arena_dalloc(chunk->arena, chunk, ptr); } else huge_dalloc(ptr); } static void malloc_print_stats(void) { if (opt_print_stats) { malloc_printf("___ Begin malloc statistics ___\n"); malloc_printf("Number of CPUs: %u\n", ncpus); malloc_printf("Number of arenas: %u\n", narenas); malloc_printf("Chunk size: %zu (2^%zu)\n", chunk_size, opt_chunk_2pow); malloc_printf("Quantum size: %zu (2^%zu)\n", quantum, opt_quantum_2pow); malloc_printf("Max small size: %zu\n", small_max); malloc_printf("Pointer size: %u\n", sizeof(void *)); malloc_printf("Assertions %s\n", #ifdef NDEBUG "disabled" #else "enabled" #endif ); #ifdef MALLOC_STATS { size_t allocated, total; unsigned i; arena_t *arena; /* Calculate and print allocated/total stats. */ /* arenas. */ for (i = 0, allocated = 0; i < narenas; i++) { if (arenas[i] != NULL) { malloc_mutex_lock(&arenas[i]->mtx); allocated += arenas[i]->stats.allocated; malloc_mutex_unlock(&arenas[i]->mtx); } } /* huge. */ malloc_mutex_lock(&chunks_mtx); allocated += huge_allocated; total = stats_chunks.curchunks * chunk_size; malloc_mutex_unlock(&chunks_mtx); malloc_printf("Allocated: %zu, space used: %zu\n", allocated, total); /* Print base stats. */ { malloc_mutex_lock(&base_mtx); malloc_printf("\nbase:\n"); malloc_printf(" %13s\n", "total"); malloc_printf(" %13llu\n", base_total); malloc_mutex_unlock(&base_mtx); } /* Print chunk stats. */ { chunk_stats_t chunks_stats; malloc_mutex_lock(&chunks_mtx); chunks_stats = stats_chunks; malloc_mutex_unlock(&chunks_mtx); malloc_printf("\nchunks:\n"); malloc_printf(" %13s%13s%13s\n", "nchunks", "highchunks", "curchunks"); malloc_printf(" %13llu%13lu%13lu\n", chunks_stats.nchunks, chunks_stats.highchunks, chunks_stats.curchunks); } /* Print chunk stats. */ malloc_printf("\nhuge:\n"); malloc_printf("%12s %12s %12s\n", "nmalloc", "ndalloc", "allocated"); malloc_printf("%12llu %12llu %12zu\n", huge_nmalloc, huge_ndalloc, huge_allocated); /* Print stats for each arena. */ for (i = 0; i < narenas; i++) { arena = arenas[i]; if (arena != NULL) { malloc_printf( "\narenas[%u] statistics:\n", i); malloc_mutex_lock(&arena->mtx); stats_print(arena); malloc_mutex_unlock(&arena->mtx); } } } #endif /* #ifdef MALLOC_STATS */ malloc_printf("--- End malloc statistics ---\n"); } } /* * FreeBSD's pthreads implementation calls malloc(3), so the malloc * implementation has to take pains to avoid infinite recursion during * initialization. */ static inline bool malloc_init(void) { if (malloc_initialized == false) return (malloc_init_hard()); return (false); } static bool malloc_init_hard(void) { unsigned i, j; int linklen; char buf[PATH_MAX + 1]; const char *opts; malloc_mutex_lock(&init_lock); if (malloc_initialized) { /* * Another thread initialized the allocator before this one * acquired init_lock. */ malloc_mutex_unlock(&init_lock); return (false); } /* Get number of CPUs. */ { int mib[2]; size_t len; mib[0] = CTL_HW; mib[1] = HW_NCPU; len = sizeof(ncpus); if (sysctl(mib, 2, &ncpus, &len, (void *) 0, 0) == -1) { /* Error. */ ncpus = 1; } } /* Get page size. */ { long result; result = sysconf(_SC_PAGESIZE); assert(result != -1); pagesize = (unsigned) result; /* * We assume that pagesize is a power of 2 when calculating * pagesize_2pow. */ assert(((result - 1) & result) == 0); pagesize_2pow = ffs(result) - 1; } for (i = 0; i < 3; i++) { /* Get runtime configuration. */ switch (i) { case 0: if ((linklen = readlink("/etc/malloc.conf", buf, sizeof(buf) - 1)) != -1) { /* * Use the contents of the "/etc/malloc.conf" * symbolic link's name. */ buf[linklen] = '\0'; opts = buf; } else { /* No configuration specified. */ buf[0] = '\0'; opts = buf; } break; case 1: if (issetugid() == 0 && (opts = getenv("MALLOC_OPTIONS")) != NULL) { /* * Do nothing; opts is already initialized to * the value of the MALLOC_OPTIONS environment * variable. */ } else { /* No configuration specified. */ buf[0] = '\0'; opts = buf; } break; case 2: if (_malloc_options != NULL) { /* * Use options that were compiled into the program. */ opts = _malloc_options; } else { /* No configuration specified. */ buf[0] = '\0'; opts = buf; } break; default: /* NOTREACHED */ assert(false); } for (j = 0; opts[j] != '\0'; j++) { switch (opts[j]) { case 'a': opt_abort = false; break; case 'A': opt_abort = true; break; case 'h': opt_hint = false; break; case 'H': opt_hint = true; break; case 'j': opt_junk = false; break; case 'J': opt_junk = true; break; case 'k': /* * Run fullness quartile limits don't have * enough resolution if there are too few * regions for the largest bin size classes. */ if (opt_chunk_2pow > pagesize_2pow + 4) opt_chunk_2pow--; break; case 'K': if (opt_chunk_2pow < CHUNK_2POW_MAX) opt_chunk_2pow++; break; case 'n': opt_narenas_lshift--; break; case 'N': opt_narenas_lshift++; break; case 'p': opt_print_stats = false; break; case 'P': opt_print_stats = true; break; case 'q': if (opt_quantum_2pow > QUANTUM_2POW_MIN) opt_quantum_2pow--; break; case 'Q': if (opt_quantum_2pow < pagesize_2pow - 1) opt_quantum_2pow++; break; case 's': if (opt_small_max_2pow > QUANTUM_2POW_MIN) opt_small_max_2pow--; break; case 'S': if (opt_small_max_2pow < pagesize_2pow - 1) opt_small_max_2pow++; break; case 'u': opt_utrace = false; break; case 'U': opt_utrace = true; break; case 'v': opt_sysv = false; break; case 'V': opt_sysv = true; break; case 'x': opt_xmalloc = false; break; case 'X': opt_xmalloc = true; break; case 'z': opt_zero = false; break; case 'Z': opt_zero = true; break; default: malloc_printf("%s: (malloc) Unsupported" " character in malloc options: '%c'\n", _getprogname(), opts[j]); } } } /* Take care to call atexit() only once. */ if (opt_print_stats) { /* Print statistics at exit. */ atexit(malloc_print_stats); } /* Set variables according to the value of opt_small_max_2pow. */ if (opt_small_max_2pow < opt_quantum_2pow) opt_small_max_2pow = opt_quantum_2pow; small_max = (1 << opt_small_max_2pow); /* Set bin-related variables. */ bin_maxclass = (pagesize >> 1); if (pagesize_2pow > RUN_MIN_REGS_2POW + 1) tiny_min_2pow = pagesize_2pow - (RUN_MIN_REGS_2POW + 1); else tiny_min_2pow = 1; assert(opt_quantum_2pow >= tiny_min_2pow); ntbins = opt_quantum_2pow - tiny_min_2pow; assert(ntbins <= opt_quantum_2pow); nqbins = (small_max >> opt_quantum_2pow); nsbins = pagesize_2pow - opt_small_max_2pow - 1; /* Set variables according to the value of opt_quantum_2pow. */ quantum = (1 << opt_quantum_2pow); quantum_mask = quantum - 1; if (ntbins > 0) small_min = (quantum >> 1) + 1; else small_min = 1; assert(small_min <= quantum); /* Set variables according to the value of opt_chunk_2pow. */ chunk_size = (1 << opt_chunk_2pow); chunk_size_mask = chunk_size - 1; arena_chunk_maplen = (1 << (opt_chunk_2pow - pagesize_2pow)); arena_maxclass = (chunk_size >> 1); UTRACE(0, 0, 0); #ifdef MALLOC_STATS memset(&stats_chunks, 0, sizeof(chunk_stats_t)); #endif /* Various sanity checks that regard configuration. */ assert(quantum >= sizeof(void *)); assert(quantum <= pagesize); assert(chunk_size >= pagesize); assert(quantum * 4 <= chunk_size); /* Initialize chunks data. */ malloc_mutex_init(&chunks_mtx); RB_INIT(&huge); #ifdef USE_BRK malloc_mutex_init(&brk_mtx); brk_base = sbrk(0); brk_prev = brk_base; brk_max = brk_base; #endif #ifdef MALLOC_STATS huge_nmalloc = 0; huge_ndalloc = 0; huge_allocated = 0; #endif RB_INIT(&old_chunks); /* Initialize base allocation data structures. */ #ifdef MALLOC_STATS base_total = 0; #endif #ifdef USE_BRK /* * 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. */ base_chunk_alloc(0); #endif base_chunk_nodes = NULL; malloc_mutex_init(&base_mtx); if (ncpus > 1) { /* * For SMP systems, create four times as many arenas as there * are CPUs by default. */ opt_narenas_lshift += 2; } /* Determine how many arenas to use. */ narenas = ncpus; if (opt_narenas_lshift > 0) { if ((narenas << opt_narenas_lshift) > narenas) narenas <<= opt_narenas_lshift; /* * Make sure not to exceed the limits of what base_malloc() * can handle. */ if (narenas * sizeof(arena_t *) > chunk_size) narenas = chunk_size / sizeof(arena_t *); } else if (opt_narenas_lshift < 0) { if ((narenas << opt_narenas_lshift) < narenas) narenas <<= opt_narenas_lshift; /* Make sure there is at least one arena. */ if (narenas == 0) narenas = 1; } #ifdef NO_TLS if (narenas > 1) { static const unsigned primes[] = {1, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263}; unsigned i, nprimes, parenas; /* * Pick a prime number of hash arenas that is more than narenas * so that direct hashing of pthread_self() pointers tends to * spread allocations evenly among the arenas. */ assert((narenas & 1) == 0); /* narenas must be even. */ nprimes = (sizeof(primes) >> SIZEOF_INT_2POW); parenas = primes[nprimes - 1]; /* In case not enough primes. */ for (i = 1; i < nprimes; i++) { if (primes[i] > narenas) { parenas = primes[i]; break; } } narenas = parenas; } #endif #ifndef NO_TLS next_arena = 0; #endif /* Allocate and initialize arenas. */ arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas); if (arenas == NULL) { malloc_mutex_unlock(&init_lock); return (true); } /* * Zero the array. In practice, this should always be pre-zeroed, * since it was just mmap()ed, but let's be sure. */ memset(arenas, 0, sizeof(arena_t *) * narenas); /* * Initialize one arena here. The rest are lazily created in * arena_choose_hard(). */ arenas_extend(0); if (arenas[0] == NULL) { malloc_mutex_unlock(&init_lock); return (true); } malloc_mutex_init(&arenas_mtx); malloc_initialized = true; malloc_mutex_unlock(&init_lock); return (false); } /* * End general internal functions. */ /******************************************************************************/ /* * Begin malloc(3)-compatible functions. */ void * malloc(size_t size) { void *ret; if (malloc_init()) { ret = NULL; goto RETURN; } if (size == 0) { if (opt_sysv == false) size = 1; else { ret = NULL; goto RETURN; } } ret = imalloc(size); RETURN: if (ret == NULL) { if (opt_xmalloc) { malloc_printf("%s: (malloc) Error in malloc(%zu):" " out of memory\n", _getprogname(), size); abort(); } errno = ENOMEM; } UTRACE(0, size, ret); return (ret); } int posix_memalign(void **memptr, size_t alignment, size_t size) { int ret; void *result; if (malloc_init()) result = NULL; else { /* Make sure that alignment is a large enough power of 2. */ if (((alignment - 1) & alignment) != 0 || alignment < sizeof(void *)) { if (opt_xmalloc) { malloc_printf("%s: (malloc) Error in" " posix_memalign(%zu, %zu):" " invalid alignment\n", _getprogname(), alignment, size); abort(); } result = NULL; ret = EINVAL; goto RETURN; } result = ipalloc(alignment, size); } if (result == NULL) { if (opt_xmalloc) { malloc_printf("%s: (malloc) Error in" " posix_memalign(%zu, %zu): out of memory\n", _getprogname(), alignment, size); abort(); } ret = ENOMEM; goto RETURN; } *memptr = result; ret = 0; RETURN: UTRACE(0, size, result); return (ret); } void * calloc(size_t num, size_t size) { void *ret; size_t num_size; if (malloc_init()) { ret = NULL; goto RETURN; } num_size = num * size; if (num_size == 0) { if ((opt_sysv == false) && ((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_printf("%s: (malloc) Error in" " calloc(%zu, %zu): out of memory\n", _getprogname(), num, size); abort(); } errno = ENOMEM; } UTRACE(0, num_size, ret); return (ret); } void * realloc(void *ptr, size_t size) { void *ret; if (size == 0) { if (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_printf("%s: (malloc) Error in" " realloc(%p, %zu): out of memory\n", _getprogname(), ptr, size); abort(); } errno = ENOMEM; } } else { if (malloc_init()) ret = NULL; else ret = imalloc(size); if (ret == NULL) { if (opt_xmalloc) { malloc_printf("%s: (malloc) Error in" " realloc(%p, %zu): out of memory\n", _getprogname(), ptr, size); 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_mutex_lock(&arenas_mtx); for (i = 0; i < narenas; i++) { if (arenas[i] != NULL) malloc_mutex_lock(&arenas[i]->mtx); } malloc_mutex_unlock(&arenas_mtx); malloc_mutex_lock(&base_mtx); malloc_mutex_lock(&chunks_mtx); } void _malloc_postfork(void) { unsigned i; /* Release all mutexes, now that fork() has completed. */ malloc_mutex_unlock(&chunks_mtx); malloc_mutex_unlock(&base_mtx); malloc_mutex_lock(&arenas_mtx); for (i = 0; i < narenas; i++) { if (arenas[i] != NULL) malloc_mutex_unlock(&arenas[i]->mtx); } malloc_mutex_unlock(&arenas_mtx); } /* * End library-private functions. */ /******************************************************************************/