/*- * Copyright (C) 2006,2007 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), * rather than as individual pages. This provides a constant-time * mechanism for associating allocations with particular arenas. * * Allocation requests are rounded up to the nearest size class, and no record * of the original request size is maintained. Allocations are broken into * categories according to size class. Assuming runtime defaults, 4 kB pages * and a 16 byte quantum, the size classes in each category are as follows: * * |=====================================| * | Category | Subcategory | Size | * |=====================================| * | Small | Tiny | 2 | * | | | 4 | * | | | 8 | * | |----------------+---------| * | | Quantum-spaced | 16 | * | | | 32 | * | | | 48 | * | | | ... | * | | | 480 | * | | | 496 | * | | | 512 | * | |----------------+---------| * | | Sub-page | 1 kB | * | | | 2 kB | * |=====================================| * | Large | 4 kB | * | | 8 kB | * | | 12 kB | * | | ... | * | | 1012 kB | * | | 1016 kB | * | | 1020 kB | * |=====================================| * | Huge | 1 MB | * | | 2 MB | * | | 3 MB | * | | ... | * |=====================================| * * A different mechanism is used for each category: * * Small : Each size class is segregated into its own set of runs. Each run * maintains a bitmap of which regions are free/allocated. * * Large : Each allocation is backed by a dedicated run. Metadata are stored * in the associated arena chunk header maps. * * Huge : Each allocation is backed by a dedicated contiguous set of chunks. * Metadata are stored in a separate red-black tree. * ******************************************************************************* */ /* * MALLOC_PRODUCTION disables assertions and statistics gathering. It also * defaults the A and J runtime options to off. These settings are appropriate * for production systems. */ /* #define MALLOC_PRODUCTION */ #ifndef MALLOC_PRODUCTION /* * MALLOC_DEBUG enables assertions and other sanity checks, and disables * inline functions. */ # define MALLOC_DEBUG /* MALLOC_STATS enables statistics calculation. */ # define MALLOC_STATS #endif /* * MALLOC_LAZY_FREE enables the use of a per-thread vector of slots that free() * can atomically stuff object pointers into. This can reduce arena lock * contention. */ #define MALLOC_LAZY_FREE /* * MALLOC_BALANCE enables monitoring of arena lock contention and dynamically * re-balances arena load if exponentially averaged contention exceeds a * certain threshold. */ #define MALLOC_BALANCE #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 #include "un-namespace.h" #ifdef MALLOC_DEBUG # ifdef NDEBUG # undef NDEBUG # endif #else # 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_2POW 2 # define USE_BRK # 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 USE_BRK # define NO_TLS #endif #ifdef __powerpc__ # define QUANTUM_2POW_MIN 4 # define SIZEOF_PTR_2POW 2 # define USE_BRK #endif #define SIZEOF_PTR (1U << SIZEOF_PTR_2POW) /* sizeof(int) == (1U << SIZEOF_INT_2POW). */ #ifndef SIZEOF_INT_2POW # define SIZEOF_INT_2POW 2 #endif /* We can't use TLS in non-PIC programs, since TLS relies on loader magic. */ #if (!defined(PIC) && !defined(NO_TLS)) # define NO_TLS #endif #ifdef NO_TLS /* MALLOC_BALANCE requires TLS. */ # ifdef MALLOC_BALANCE # undef MALLOC_BALANCE # endif /* MALLOC_LAZY_FREE requires TLS. */ # ifdef MALLOC_LAZY_FREE # undef MALLOC_LAZY_FREE # endif #endif /* * Size and alignment of memory chunks that are allocated by the OS's virtual * memory system. */ #define CHUNK_2POW_DEFAULT 20 /* * Maximum size of L1 cache line. This is used to avoid cache line aliasing, * so over-estimates are okay (up to a point), but under-estimates will * negatively affect performance. */ #define CACHELINE_2POW 6 #define CACHELINE ((size_t)(1U << CACHELINE_2POW)) /* Smallest size class to support. */ #define TINY_MIN_2POW 1 /* * Maximum size class that is a multiple of the quantum, but not (necessarily) * a power of 2. Above this size, allocations are rounded up to the nearest * power of 2. */ #define SMALL_MAX_2POW_DEFAULT 9 #define SMALL_MAX_DEFAULT (1U << SMALL_MAX_2POW_DEFAULT) /* * RUN_MAX_OVRHD indicates maximum desired run header overhead. Runs are sized * as small as possible such that this setting is still honored, without * violating other constraints. The goal is to make runs as small as possible * without exceeding a per run external fragmentation threshold. * * We use binary fixed point math for overhead computations, where the binary * point is implicitly RUN_BFP bits to the left. * * Note that it is possible to set RUN_MAX_OVRHD low enough that it cannot be * honored for some/all object sizes, since there is one bit of header overhead * per object (plus a constant). This constraint is relaxed (ignored) for runs * that are so small that the per-region overhead is greater than: * * (RUN_MAX_OVRHD / (reg_size << (3+RUN_BFP)) */ #define RUN_BFP 12 /* \/ Implicit binary fixed point. */ #define RUN_MAX_OVRHD 0x0000003dU #define RUN_MAX_OVRHD_RELAX 0x00001800U /* Put a cap on small object run size. This overrides RUN_MAX_OVRHD. */ #define RUN_MAX_SMALL_2POW 15 #define RUN_MAX_SMALL (1U << RUN_MAX_SMALL_2POW) #ifdef MALLOC_LAZY_FREE /* Default size of each arena's lazy free cache. */ # define LAZY_FREE_2POW_DEFAULT 8 /* * Number of pseudo-random probes to conduct before considering the cache to * be overly full. It takes on average n probes to detect fullness of * (n-1)/n. However, we are effectively doing multiple non-independent * trials (each deallocation is a trial), so the actual average threshold * for clearing the cache is somewhat lower. */ # define LAZY_FREE_NPROBES 5 #endif /* * Hyper-threaded CPUs may need a special instruction inside spin loops in * order to yield to another virtual CPU. If no such instruction is defined * above, make CPU_SPINWAIT a no-op. */ #ifndef CPU_SPINWAIT # define CPU_SPINWAIT #endif /* * Adaptive spinning must eventually switch to blocking, in order to avoid the * potential for priority inversion deadlock. Backing off past a certain point * can actually waste time. */ #define SPIN_LIMIT_2POW 11 /* * Conversion from spinning to blocking is expensive; we use (1U << * BLOCK_COST_2POW) to estimate how many more times costly blocking is than * worst-case spinning. */ #define BLOCK_COST_2POW 4 #ifdef MALLOC_BALANCE /* * We use an exponential moving average to track recent lock contention, * where the size of the history window is N, and alpha=2/(N+1). * * Due to integer math rounding, very small values here can cause * substantial degradation in accuracy, thus making the moving average decay * faster than it would with precise calculation. */ # define BALANCE_ALPHA_INV_2POW 9 /* * Threshold value for the exponential moving contention average at which to * re-assign a thread. */ # define BALANCE_THRESHOLD_DEFAULT (1U << (SPIN_LIMIT_2POW-4)) #endif /******************************************************************************/ /* * Mutexes based on spinlocks. We can't use normal pthread spinlocks in all * places, because they require malloc()ed memory, which causes bootstrapping * issues in some cases. */ typedef struct { spinlock_t lock; } malloc_mutex_t; /* Set to true once the allocator has been initialized. */ static bool malloc_initialized = false; /* Used to avoid initialization races. */ static malloc_mutex_t init_lock = {_SPINLOCK_INITIALIZER}; /******************************************************************************/ /* * Statistics data structures. */ #ifdef MALLOC_STATS typedef struct malloc_bin_stats_s malloc_bin_stats_t; struct malloc_bin_stats_s { /* * Number of allocation requests that corresponded to the size of this * bin. */ uint64_t nrequests; /* Total number of runs created for this bin's size class. */ uint64_t nruns; /* * Total number of runs reused by extracting them from the runs tree for * this bin's size class. */ uint64_t reruns; /* High-water mark for this bin. */ unsigned long highruns; /* Current number of runs in this bin. */ unsigned long curruns; }; typedef struct arena_stats_s arena_stats_t; struct arena_stats_s { /* Number of bytes currently mapped. */ size_t mapped; /* Per-size-category statistics. */ size_t allocated_small; uint64_t nmalloc_small; uint64_t ndalloc_small; size_t allocated_large; uint64_t nmalloc_large; uint64_t ndalloc_large; #ifdef MALLOC_BALANCE /* Number of times this arena reassigned a thread due to contention. */ uint64_t nbalance; #endif }; typedef struct chunk_stats_s chunk_stats_t; struct chunk_stats_s { /* Number of chunks that were allocated. */ uint64_t nchunks; /* High-water mark for number of chunks allocated. */ unsigned long highchunks; /* * Current number of chunks allocated. This value isn't maintained for * any other purpose, so keep track of it in order to be able to set * highchunks. */ unsigned long curchunks; }; #endif /* #ifdef MALLOC_STATS */ /******************************************************************************/ /* * Chunk data structures. */ /* Tree of chunks. */ typedef struct chunk_node_s chunk_node_t; struct chunk_node_s { /* Linkage for the chunk tree. */ RB_ENTRY(chunk_node_s) link; /* * Pointer to the chunk that this tree node is responsible for. In some * (but certainly not all) cases, this data structure is placed at the * beginning of the corresponding chunk, so this field may point to this * node. */ void *chunk; /* Total chunk size. */ size_t size; }; typedef struct chunk_tree_s chunk_tree_t; RB_HEAD(chunk_tree_s, chunk_node_s); /******************************************************************************/ /* * Arena data structures. */ typedef struct arena_s arena_t; typedef struct arena_bin_s arena_bin_t; typedef struct arena_chunk_map_s arena_chunk_map_t; struct arena_chunk_map_s { /* * Number of pages in run. For a free run that has never been touched, * this is NPAGES_EMPTY for the central pages, which allows us to avoid * zero-filling untouched pages for calloc(). */ #define NPAGES_EMPTY ((uint32_t)0x0U) uint32_t npages; /* * Position within run. For a free run, this is POS_EMPTY/POS_FREE for * the first and last pages. The special values make it possible to * quickly coalesce free runs. POS_EMPTY indicates that the run has * never been touched, which allows us to avoid zero-filling untouched * pages for calloc(). * * This is the limiting factor for chunksize; there can be at most 2^31 * pages in a run. * * POS_EMPTY is assumed by arena_run_dalloc() to be less than POS_FREE. */ #define POS_EMPTY ((uint32_t)0xfffffffeU) #define POS_FREE ((uint32_t)0xffffffffU) uint32_t pos; }; /* Arena chunk header. */ typedef struct arena_chunk_s arena_chunk_t; struct arena_chunk_s { /* Arena that owns the chunk. */ arena_t *arena; /* Linkage for the arena's chunk tree. */ RB_ENTRY(arena_chunk_s) link; /* * Number of pages in use. This is maintained in order to make * detection of empty chunks fast. */ uint32_t pages_used; /* * Every time a free run larger than this value is created/coalesced, * this value is increased. The only way that the value decreases is if * arena_run_alloc() fails to find a free run as large as advertised by * this value. */ uint32_t max_frun_npages; /* * Every time a free run that starts at an earlier page than this value * is created/coalesced, this value is decreased. It is reset in a * similar fashion to max_frun_npages. */ uint32_t min_frun_ind; /* * Map of pages within chunk that keeps track of free/large/small. For * free runs, only the map entries for the first and last pages are * kept up to date, so that free runs can be quickly coalesced. */ arena_chunk_map_t map[1]; /* Dynamically sized. */ }; typedef struct arena_chunk_tree_s arena_chunk_tree_t; RB_HEAD(arena_chunk_tree_s, arena_chunk_s); typedef struct arena_run_s arena_run_t; struct arena_run_s { /* Linkage for run trees. */ RB_ENTRY(arena_run_s) link; #ifdef MALLOC_DEBUG uint32_t magic; # define ARENA_RUN_MAGIC 0x384adf93 #endif /* Bin this run is associated with. */ arena_bin_t *bin; /* Index of first element that might have a free region. */ unsigned regs_minelm; /* Number of free regions in run. */ unsigned nfree; /* Bitmask of in-use regions (0: in use, 1: free). */ unsigned regs_mask[1]; /* Dynamically sized. */ }; typedef struct arena_run_tree_s arena_run_tree_t; RB_HEAD(arena_run_tree_s, arena_run_s); struct arena_bin_s { /* * Current run being used to service allocations of this bin's size * class. */ arena_run_t *runcur; /* * Tree of non-full runs. This tree is used when looking for an * existing run when runcur is no longer usable. We choose the * non-full run that is lowest in memory; this policy tends to keep * objects packed well, and it can also help reduce the number of * almost-empty chunks. */ arena_run_tree_t runs; /* Size of regions in a run for this bin's size class. */ size_t reg_size; /* Total size of a run for this bin's size class. */ size_t run_size; /* Total number of regions in a run for this bin's size class. */ uint32_t nregs; /* Number of elements in a run's regs_mask for this bin's size class. */ uint32_t regs_mask_nelms; /* Offset of first region in a run for this bin's size class. */ uint32_t reg0_offset; #ifdef MALLOC_STATS /* Bin statistics. */ malloc_bin_stats_t stats; #endif }; struct arena_s { #ifdef MALLOC_DEBUG uint32_t magic; # define ARENA_MAGIC 0x947d3d24 #endif /* All operations on this arena require that lock be locked. */ pthread_mutex_t lock; #ifdef MALLOC_STATS arena_stats_t stats; #endif /* * Tree of chunks this arena manages. */ arena_chunk_tree_t chunks; /* * In order to avoid rapid chunk allocation/deallocation when an arena * oscillates right on the cusp of needing a new chunk, cache the most * recently freed chunk. This caching is disabled by opt_hint. * * There is one spare chunk per arena, rather than one spare total, in * order to avoid interactions between multiple threads that could make * a single spare inadequate. */ arena_chunk_t *spare; #ifdef MALLOC_BALANCE /* * The arena load balancing machinery needs to keep track of how much * lock contention there is. This value is exponentially averaged. */ uint32_t contention; #endif #ifdef MALLOC_LAZY_FREE /* * Deallocation of small objects can be lazy, in which case free_cache * stores pointers to those objects that have not yet been deallocated. * In order to avoid lock contention, slots are chosen randomly. Empty * slots contain NULL. */ void **free_cache; #endif /* * bins is used to store rings of free regions of the following sizes, * assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS. * * bins[i] | size | * --------+------+ * 0 | 2 | * 1 | 4 | * 2 | 8 | * --------+------+ * 3 | 16 | * 4 | 32 | * 5 | 48 | * 6 | 64 | * : : * : : * 33 | 496 | * 34 | 512 | * --------+------+ * 35 | 1024 | * 36 | 2048 | * --------+------+ */ arena_bin_t bins[1]; /* Dynamically sized. */ }; /******************************************************************************/ /* * Data. */ /* Number of CPUs. */ static unsigned ncpus; /* VM page size. */ static size_t pagesize; static size_t pagesize_mask; static size_t pagesize_2pow; /* Various bin-related settings. */ static size_t bin_maxclass; /* Max size class for bins. */ static unsigned ntbins; /* Number of (2^n)-spaced tiny bins. */ static unsigned nqbins; /* Number of quantum-spaced bins. */ static unsigned nsbins; /* Number of (2^n)-spaced sub-page bins. */ static size_t small_min; static size_t small_max; /* Various quantum-related settings. */ static size_t quantum; static size_t quantum_mask; /* (quantum - 1). */ /* Various chunk-related settings. */ static size_t chunksize; static size_t chunksize_mask; /* (chunksize - 1). */ static unsigned chunk_npages; static unsigned arena_chunk_header_npages; static size_t arena_maxclass; /* Max size class for arenas. */ /********/ /* * Chunks. */ /* Protects chunk-related data structures. */ static malloc_mutex_t chunks_mtx; /* Tree of chunks that are stand-alone huge allocations. */ static chunk_tree_t huge; #ifdef 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_pages_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 /* Huge allocation statistics. */ static uint64_t huge_nmalloc; static uint64_t huge_ndalloc; static size_t huge_allocated; #endif /* * Tree of chunks that were previously allocated. This is used when allocating * chunks, in an attempt to re-use address space. */ static chunk_tree_t old_chunks; /****************************/ /* * base (internal allocation). */ /* * Current pages that are being used for internal memory allocations. These * pages are carved up in cacheline-size quanta, so that there is no chance of * false cache line sharing. */ static void *base_pages; static void *base_next_addr; static void *base_past_addr; /* Addr immediately past base_pages. */ static chunk_node_t *base_chunk_nodes; /* LIFO cache of chunk nodes. */ static malloc_mutex_t base_mtx; #ifdef MALLOC_STATS static size_t base_mapped; #endif /********/ /* * Arenas. */ /* * Arenas that are used to service external requests. Not all elements of the * arenas array are necessarily used; arenas are created lazily as needed. */ static arena_t **arenas; static unsigned narenas; #ifndef NO_TLS # ifdef MALLOC_BALANCE static unsigned narenas_2pow; # else static unsigned next_arena; # endif #endif static pthread_mutex_t arenas_lock; /* Protects arenas initialization. */ #ifndef NO_TLS /* * Map of pthread_self() --> arenas[???], used for selecting an arena to use * for allocations. */ static __thread arena_t *arenas_map; #endif #ifdef MALLOC_STATS /* Chunk statistics. */ static chunk_stats_t stats_chunks; #endif /*******************************/ /* * Runtime configuration options. */ const char *_malloc_options; #ifndef MALLOC_PRODUCTION static bool opt_abort = true; static bool opt_junk = true; #else static bool opt_abort = false; static bool opt_junk = false; #endif static bool opt_hint = false; #ifdef MALLOC_LAZY_FREE static int opt_lazy_free_2pow = LAZY_FREE_2POW_DEFAULT; #endif #ifdef MALLOC_BALANCE static uint64_t opt_balance_threshold = BALANCE_THRESHOLD_DEFAULT; #endif static bool opt_print_stats = false; static size_t opt_quantum_2pow = QUANTUM_2POW_MIN; static size_t opt_small_max_2pow = SMALL_MAX_2POW_DEFAULT; static size_t opt_chunk_2pow = CHUNK_2POW_DEFAULT; static bool opt_utrace = false; static bool opt_sysv = false; static bool opt_xmalloc = false; static bool opt_zero = false; static int opt_narenas_lshift = 0; typedef struct { void *p; size_t s; void *r; } malloc_utrace_t; #define UTRACE(a, b, c) \ if (opt_utrace) { \ malloc_utrace_t ut = {a, b, c}; \ utrace(&ut, sizeof(ut)); \ } /******************************************************************************/ /* * Begin function prototypes for non-inline static functions. */ static void malloc_mutex_init(malloc_mutex_t *mutex); static bool malloc_spin_init(pthread_mutex_t *lock); static void wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4); #ifdef MALLOC_STATS static void malloc_printf(const char *format, ...); #endif static char *umax2s(uintmax_t x, char *s); static bool base_pages_alloc(size_t minsize); static void *base_alloc(size_t size); static void *base_calloc(size_t number, size_t size); static chunk_node_t *base_chunk_node_alloc(void); static void base_chunk_node_dealloc(chunk_node_t *node); #ifdef MALLOC_STATS static void stats_print(arena_t *arena); #endif static void *pages_map(void *addr, size_t size); static void pages_unmap(void *addr, size_t size); static void *chunk_alloc(size_t size); static void chunk_dealloc(void *chunk, size_t size); #ifndef NO_TLS static arena_t *choose_arena_hard(void); #endif static void arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool zero); static arena_chunk_t *arena_chunk_alloc(arena_t *arena); static void arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk); static arena_run_t *arena_run_alloc(arena_t *arena, size_t size, bool zero); static void arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size); static arena_run_t *arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin); static void *arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin); static size_t arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size); static void *arena_malloc(arena_t *arena, size_t size, bool zero); static void *arena_palloc(arena_t *arena, size_t alignment, size_t size, size_t alloc_size); static size_t arena_salloc(const void *ptr); static void *arena_ralloc(void *ptr, size_t size, size_t oldsize); static void arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr); static bool arena_new(arena_t *arena); static arena_t *arenas_extend(unsigned ind); static void *huge_malloc(size_t size, bool zero); static void *huge_palloc(size_t alignment, size_t size); static void *huge_ralloc(void *ptr, size_t size, size_t oldsize); static void huge_dalloc(void *ptr); static void *imalloc(size_t size); static void *ipalloc(size_t alignment, size_t size); static void *icalloc(size_t size); static size_t isalloc(const void *ptr); static void *iralloc(void *ptr, size_t size); static void idalloc(void *ptr); static void malloc_print_stats(void); static bool malloc_init_hard(void); /* * End function prototypes. */ /******************************************************************************/ /* * Begin mutex. We can't use normal pthread mutexes in all places, because * they require malloc()ed memory, which causes bootstrapping issues in some * cases. */ static void malloc_mutex_init(malloc_mutex_t *mutex) { static const spinlock_t lock = _SPINLOCK_INITIALIZER; mutex->lock = lock; } static inline void malloc_mutex_lock(malloc_mutex_t *mutex) { if (__isthreaded) _SPINLOCK(&mutex->lock); } static inline void malloc_mutex_unlock(malloc_mutex_t *mutex) { if (__isthreaded) _SPINUNLOCK(&mutex->lock); } /* * End mutex. */ /******************************************************************************/ /* * Begin spin lock. Spin locks here are actually adaptive mutexes that block * after a period of spinning, because unbounded spinning would allow for * priority inversion. */ /* * We use an unpublished interface to initialize pthread mutexes with an * allocation callback, in order to avoid infinite recursion. */ int _pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex, void *(calloc_cb)(size_t, size_t)); __weak_reference(_pthread_mutex_init_calloc_cb_stub, _pthread_mutex_init_calloc_cb); int _pthread_mutex_init_calloc_cb_stub(pthread_mutex_t *mutex, void *(calloc_cb)(size_t, size_t)) { return (0); } static bool malloc_spin_init(pthread_mutex_t *lock) { if (_pthread_mutex_init_calloc_cb(lock, base_calloc) != 0) return (true); return (false); } static inline unsigned malloc_spin_lock(pthread_mutex_t *lock) { unsigned ret = 0; if (__isthreaded) { if (_pthread_mutex_trylock(lock) != 0) { unsigned i; volatile unsigned j; /* Exponentially back off. */ for (i = 1; i <= SPIN_LIMIT_2POW; i++) { for (j = 0; j < (1U << i); j++) ret++; CPU_SPINWAIT; if (_pthread_mutex_trylock(lock) == 0) return (ret); } /* * Spinning failed. Block until the lock becomes * available, in order to avoid indefinite priority * inversion. */ _pthread_mutex_lock(lock); assert((ret << BLOCK_COST_2POW) != 0); return (ret << BLOCK_COST_2POW); } } return (ret); } static inline void malloc_spin_unlock(pthread_mutex_t *lock) { if (__isthreaded) _pthread_mutex_unlock(lock); } /* * End spin lock. */ /******************************************************************************/ /* * Begin Utility functions/macros. */ /* Return the chunk address for allocation address a. */ #define CHUNK_ADDR2BASE(a) \ ((void *)((uintptr_t)(a) & ~chunksize_mask)) /* Return the chunk offset of address a. */ #define CHUNK_ADDR2OFFSET(a) \ ((size_t)((uintptr_t)(a) & chunksize_mask)) /* Return the smallest chunk multiple that is >= s. */ #define CHUNK_CEILING(s) \ (((s) + chunksize_mask) & ~chunksize_mask) /* Return the smallest cacheline multiple that is >= s. */ #define CACHELINE_CEILING(s) \ (((s) + (CACHELINE - 1)) & ~(CACHELINE - 1)) /* Return the smallest quantum multiple that is >= a. */ #define QUANTUM_CEILING(a) \ (((a) + quantum_mask) & ~quantum_mask) /* Return the smallest pagesize multiple that is >= s. */ #define PAGE_CEILING(s) \ (((s) + pagesize_mask) & ~pagesize_mask) /* Compute the smallest power of 2 that is >= x. */ static inline size_t pow2_ceil(size_t x) { x--; x |= x >> 1; x |= x >> 2; x |= x >> 4; x |= x >> 8; x |= x >> 16; #if (SIZEOF_PTR == 8) x |= x >> 32; #endif x++; return (x); } #if (defined(MALLOC_LAZY_FREE) || defined(MALLOC_BALANCE)) /* * Use a simple linear congruential pseudo-random number generator: * * prn(y) = (a*x + c) % m * * where the following constants ensure maximal period: * * a == Odd number (relatively prime to 2^n), and (a-1) is a multiple of 4. * c == Odd number (relatively prime to 2^n). * m == 2^32 * * See Knuth's TAOCP 3rd Ed., Vol. 2, pg. 17 for details on these constraints. * * This choice of m has the disadvantage that the quality of the bits is * proportional to bit position. For example. the lowest bit has a cycle of 2, * the next has a cycle of 4, etc. For this reason, we prefer to use the upper * bits. */ # define PRN_DEFINE(suffix, var, a, c) \ static inline void \ sprn_##suffix(uint32_t seed) \ { \ var = seed; \ } \ \ static inline uint32_t \ prn_##suffix(uint32_t lg_range) \ { \ uint32_t ret, x; \ \ assert(lg_range > 0); \ assert(lg_range <= 32); \ \ x = (var * (a)) + (c); \ var = x; \ ret = x >> (32 - lg_range); \ \ return (ret); \ } # define SPRN(suffix, seed) sprn_##suffix(seed) # define PRN(suffix, lg_range) prn_##suffix(lg_range) #endif /* * Define PRNGs, one for each purpose, in order to avoid auto-correlation * problems. */ #ifdef MALLOC_LAZY_FREE /* Define the per-thread PRNG used for lazy deallocation. */ static __thread uint32_t lazy_free_x; PRN_DEFINE(lazy_free, lazy_free_x, 12345, 12347) #endif #ifdef MALLOC_BALANCE /* Define the PRNG used for arena assignment. */ static __thread uint32_t balance_x; PRN_DEFINE(balance, balance_x, 1297, 1301) #endif static void wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4) { _write(STDERR_FILENO, p1, strlen(p1)); _write(STDERR_FILENO, p2, strlen(p2)); _write(STDERR_FILENO, p3, strlen(p3)); _write(STDERR_FILENO, p4, strlen(p4)); } void (*_malloc_message)(const char *p1, const char *p2, const char *p3, const char *p4) = wrtmessage; #ifdef MALLOC_STATS /* * Print to stderr in such a way as to (hopefully) avoid memory allocation. */ static void malloc_printf(const char *format, ...) { char buf[4096]; va_list ap; va_start(ap, format); vsnprintf(buf, sizeof(buf), format, ap); va_end(ap); _malloc_message(buf, "", "", ""); } #endif /* * We don't want to depend on vsnprintf() for production builds, since that can * cause unnecessary bloat for static binaries. umax2s() provides minimal * integer printing functionality, so that malloc_printf() use can be limited to * MALLOC_STATS code. */ #define UMAX2S_BUFSIZE 21 static char * umax2s(uintmax_t x, char *s) { unsigned i; /* Make sure UMAX2S_BUFSIZE is large enough. */ assert(sizeof(uintmax_t) <= 8); i = UMAX2S_BUFSIZE - 1; s[i] = '\0'; do { i--; s[i] = "0123456789"[x % 10]; x /= 10; } while (x > 0); return (&s[i]); } /******************************************************************************/ static bool base_pages_alloc(size_t minsize) { size_t csize; #ifdef USE_BRK /* * Do special brk allocation here, since base allocations don't need to * be chunk-aligned. */ if (brk_prev != (void *)-1) { void *brk_cur; intptr_t incr; if (minsize != 0) csize = CHUNK_CEILING(minsize); 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)chunksize - (intptr_t)CHUNK_ADDR2OFFSET(brk_cur); if (incr < minsize) incr += csize; brk_prev = sbrk(incr); if (brk_prev == brk_cur) { /* Success. */ malloc_mutex_unlock(&brk_mtx); base_pages = brk_cur; base_next_addr = base_pages; base_past_addr = (void *)((uintptr_t)base_pages + incr); #ifdef MALLOC_STATS base_mapped += incr; #endif return (false); } } while (brk_prev != (void *)-1); malloc_mutex_unlock(&brk_mtx); } if (minsize == 0) { /* * Failure during initialization doesn't matter, so avoid * falling through to the mmap-based page mapping code. */ return (true); } #endif 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 void * base_alloc(size_t size) { void *ret; size_t csize; /* Round size up to nearest multiple of the cacheline size. */ csize = CACHELINE_CEILING(size); malloc_mutex_lock(&base_mtx); /* Make sure there's enough space for the allocation. */ if ((uintptr_t)base_next_addr + csize > (uintptr_t)base_past_addr) { if (base_pages_alloc(csize)) { ret = NULL; goto RETURN; } } /* Allocate. */ ret = base_next_addr; base_next_addr = (void *)((uintptr_t)base_next_addr + csize); RETURN: malloc_mutex_unlock(&base_mtx); return (ret); } static void * base_calloc(size_t number, size_t size) { void *ret; ret = base_alloc(number * size); memset(ret, 0, number * size); return (ret); } static chunk_node_t * base_chunk_node_alloc(void) { chunk_node_t *ret; malloc_mutex_lock(&base_mtx); if (base_chunk_nodes != NULL) { ret = base_chunk_nodes; base_chunk_nodes = *(chunk_node_t **)ret; malloc_mutex_unlock(&base_mtx); } else { malloc_mutex_unlock(&base_mtx); ret = (chunk_node_t *)base_alloc(sizeof(chunk_node_t)); } return (ret); } static void base_chunk_node_dealloc(chunk_node_t *node) { malloc_mutex_lock(&base_mtx); *(chunk_node_t **)node = base_chunk_nodes; base_chunk_nodes = node; malloc_mutex_unlock(&base_mtx); } /******************************************************************************/ #ifdef MALLOC_STATS static void stats_print(arena_t *arena) { unsigned i, gap_start; malloc_printf( " allocated/mapped nmalloc ndalloc\n"); malloc_printf("small: %12llu %-12s %12llu %12llu\n", arena->stats.allocated_small, "", arena->stats.nmalloc_small, arena->stats.ndalloc_small); malloc_printf("large: %12llu %-12s %12llu %12llu\n", arena->stats.allocated_large, "", arena->stats.nmalloc_large, arena->stats.ndalloc_large); malloc_printf("total: %12llu/%-12llu %12llu %12llu\n", arena->stats.allocated_small + arena->stats.allocated_large, arena->stats.mapped, arena->stats.nmalloc_small + arena->stats.nmalloc_large, arena->stats.ndalloc_small + arena->stats.ndalloc_large); malloc_printf("bins: bin size regs pgs requests newruns" " reruns maxruns curruns\n"); for (i = 0, gap_start = UINT_MAX; i < ntbins + nqbins + nsbins; i++) { if (arena->bins[i].stats.nrequests == 0) { if (gap_start == UINT_MAX) gap_start = i; } else { if (gap_start != UINT_MAX) { if (i > gap_start + 1) { /* Gap of more than one size class. */ malloc_printf("[%u..%u]\n", gap_start, i - 1); } else { /* Gap of one size class. */ malloc_printf("[%u]\n", gap_start); } gap_start = UINT_MAX; } malloc_printf( "%13u %1s %4u %4u %3u %9llu %9llu" " %9llu %7lu %7lu\n", i, i < ntbins ? "T" : i < ntbins + nqbins ? "Q" : "S", arena->bins[i].reg_size, arena->bins[i].nregs, arena->bins[i].run_size >> pagesize_2pow, arena->bins[i].stats.nrequests, arena->bins[i].stats.nruns, arena->bins[i].stats.reruns, arena->bins[i].stats.highruns, arena->bins[i].stats.curruns); } } if (gap_start != UINT_MAX) { if (i > gap_start + 1) { /* Gap of more than one size class. */ malloc_printf("[%u..%u]\n", gap_start, i - 1); } else { /* Gap of one size class. */ malloc_printf("[%u]\n", gap_start); } } } #endif /* * End Utility functions/macros. */ /******************************************************************************/ /* * Begin chunk management functions. */ static inline int chunk_comp(chunk_node_t *a, chunk_node_t *b) { assert(a != NULL); assert(b != NULL); if ((uintptr_t)a->chunk < (uintptr_t)b->chunk) return (-1); else if (a->chunk == b->chunk) return (0); else return (1); } /* Generate red-black tree code for chunks. */ RB_GENERATE_STATIC(chunk_tree_s, chunk_node_s, link, chunk_comp) static void * pages_map(void *addr, size_t size) { void *ret; /* * We don't use MAP_FIXED here, because it can cause the *replacement* * of existing mappings, and we only want to create new mappings. */ ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); assert(ret != NULL); if (ret == MAP_FAILED) ret = NULL; else if (addr != NULL && ret != addr) { /* * We succeeded in mapping memory, but not in the right place. */ if (munmap(ret, size) == -1) { char buf[STRERROR_BUF]; strerror_r(errno, buf, sizeof(buf)); _malloc_message(_getprogname(), ": (malloc) Error in munmap(): ", buf, "\n"); if (opt_abort) abort(); } ret = NULL; } assert(ret == NULL || (addr == NULL && ret != addr) || (addr != NULL && ret == addr)); return (ret); } static void pages_unmap(void *addr, size_t size) { if (munmap(addr, size) == -1) { char buf[STRERROR_BUF]; strerror_r(errno, buf, sizeof(buf)); _malloc_message(_getprogname(), ": (malloc) Error in munmap(): ", buf, "\n"); if (opt_abort) abort(); } } static void * chunk_alloc(size_t size) { void *ret, *chunk; chunk_node_t *tchunk, *delchunk; assert(size != 0); assert((size & chunksize_mask) == 0); malloc_mutex_lock(&chunks_mtx); if (size == chunksize) { /* * Check for address ranges that were previously chunks and try * to use them. */ tchunk = RB_MIN(chunk_tree_s, &old_chunks); while (tchunk != NULL) { /* Found an address range. Try to recycle it. */ chunk = tchunk->chunk; delchunk = tchunk; tchunk = RB_NEXT(chunk_tree_s, &old_chunks, delchunk); /* Remove delchunk from the tree. */ RB_REMOVE(chunk_tree_s, &old_chunks, delchunk); base_chunk_node_dealloc(delchunk); #ifdef 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; /* * Maintain invariant that all newly allocated * chunks are untouched or zero-filled. */ memset(ret, 0, size); goto RETURN; } #endif if ((ret = pages_map(chunk, size)) != NULL) { /* Success. */ goto RETURN; } } } /* * Try to over-allocate, but allow the OS to place the allocation * anywhere. Beware of size_t wrap-around. */ if (size + chunksize > size) { if ((ret = pages_map(NULL, size + chunksize)) != NULL) { size_t offset = CHUNK_ADDR2OFFSET(ret); /* * Success. Clean up unneeded leading/trailing space. */ if (offset != 0) { /* Leading space. */ pages_unmap(ret, chunksize - offset); ret = (void *)((uintptr_t)ret + (chunksize - offset)); /* Trailing space. */ pages_unmap((void *)((uintptr_t)ret + size), offset); } else { /* Trailing space only. */ pages_unmap((void *)((uintptr_t)ret + size), chunksize); } 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 /* All strategies for allocation failed. */ ret = NULL; RETURN: if (ret != NULL) { chunk_node_t key; /* * Clean out any entries in old_chunks that overlap with the * memory we just allocated. */ key.chunk = ret; tchunk = RB_NFIND(chunk_tree_s, &old_chunks, &key); while (tchunk != NULL && (uintptr_t)tchunk->chunk >= (uintptr_t)ret && (uintptr_t)tchunk->chunk < (uintptr_t)ret + size) { delchunk = tchunk; tchunk = RB_NEXT(chunk_tree_s, &old_chunks, delchunk); RB_REMOVE(chunk_tree_s, &old_chunks, delchunk); base_chunk_node_dealloc(delchunk); } } #ifdef MALLOC_STATS if (ret != NULL) { stats_chunks.nchunks += (size / chunksize); stats_chunks.curchunks += (size / chunksize); } if (stats_chunks.curchunks > stats_chunks.highchunks) stats_chunks.highchunks = stats_chunks.curchunks; #endif malloc_mutex_unlock(&chunks_mtx); assert(CHUNK_ADDR2BASE(ret) == ret); return (ret); } static void chunk_dealloc(void *chunk, size_t size) { chunk_node_t *node; assert(chunk != NULL); assert(CHUNK_ADDR2BASE(chunk) == chunk); assert(size != 0); assert((size & chunksize_mask) == 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; } } else { size_t offset; malloc_mutex_unlock(&brk_mtx); madvise(chunk, size, MADV_FREE); /* * Iteratively create records of each chunk-sized * memory region that 'chunk' is comprised of, so that * the address range can be recycled if memory usage * increases later on. */ for (offset = 0; offset < size; offset += chunksize) { node = base_chunk_node_alloc(); if (node == NULL) break; node->chunk = (void *)((uintptr_t)chunk + (uintptr_t)offset); node->size = chunksize; RB_INSERT(chunk_tree_s, &old_chunks, node); } } } else { #endif pages_unmap(chunk, size); /* * Make a record of the chunk's address, so that the address * range can be recycled if memory usage increases later on. * Don't bother to create entries if (size > chunksize), since * doing so could cause scalability issues for truly gargantuan * objects (many gigabytes or larger). */ if (size == chunksize) { node = base_chunk_node_alloc(); if (node != NULL) { node->chunk = (void *)(uintptr_t)chunk; node->size = chunksize; RB_INSERT(chunk_tree_s, &old_chunks, node); } } #ifdef USE_BRK } #endif #ifdef MALLOC_STATS stats_chunks.curchunks -= (size / chunksize); #endif malloc_mutex_unlock(&chunks_mtx); } /* * End chunk management functions. */ /******************************************************************************/ /* * Begin arena. */ /* * Choose an arena based on a per-thread value (fast-path code, calls slow-path * code if necessary). */ static inline arena_t * choose_arena(void) { arena_t *ret; /* * We can only use TLS if this is a PIC library, since for the static * library version, libc's malloc is used by TLS allocation, which * introduces a bootstrapping issue. */ #ifndef NO_TLS if (__isthreaded == false) { /* * Avoid the overhead of TLS for single-threaded operation. If the * app switches to threaded mode, the initial thread may end up * being assigned to some other arena, but this one-time switch * shouldn't cause significant issues. */ return (arenas[0]); } ret = arenas_map; if (ret == NULL) { ret = choose_arena_hard(); assert(ret != NULL); } #else if (__isthreaded) { unsigned long ind; /* * Hash _pthread_self() to one of the arenas. There is a prime * number of arenas, so this has a reasonable chance of * working. Even so, the hashing can be easily thwarted by * inconvenient _pthread_self() values. Without specific * knowledge of how _pthread_self() calculates values, we can't * easily do much better than this. */ ind = (unsigned long) _pthread_self() % narenas; /* * Optimistially assume that arenas[ind] has been initialized. * At worst, we find out that some other thread has already * done so, after acquiring the lock in preparation. Note that * this lazy locking also has the effect of lazily forcing * cache coherency; without the lock acquisition, there's no * guarantee that modification of arenas[ind] by another thread * would be seen on this CPU for an arbitrary amount of time. * * In general, this approach to modifying a synchronized value * isn't a good idea, but in this case we only ever modify the * value once, so things work out well. */ ret = arenas[ind]; if (ret == NULL) { /* * Avoid races with another thread that may have already * initialized arenas[ind]. */ malloc_spin_lock(&arenas_lock); if (arenas[ind] == NULL) ret = arenas_extend((unsigned)ind); else ret = arenas[ind]; malloc_spin_unlock(&arenas_lock); } } else ret = arenas[0]; #endif assert(ret != NULL); return (ret); } #ifndef NO_TLS /* * Choose an arena based on a per-thread value (slow-path code only, called * only by choose_arena()). */ static arena_t * choose_arena_hard(void) { arena_t *ret; assert(__isthreaded); #ifdef MALLOC_LAZY_FREE /* * Seed the PRNG used for lazy deallocation. Since seeding only occurs * on the first allocation by a thread, it is possible for a thread to * deallocate before seeding. This is not a critical issue though, * since it is extremely unusual for an application to to use threads * that deallocate but *never* allocate, and because even if seeding * never occurs for multiple threads, they will tend to drift apart * unless some aspect of the application forces deallocation * synchronization. */ SPRN(lazy_free, (uint32_t)(uintptr_t)(_pthread_self())); #endif #ifdef MALLOC_BALANCE /* * Seed the PRNG used for arena load balancing. We can get away with * using the same seed here as for the lazy_free PRNG without * introducing autocorrelation because the PRNG parameters are * distinct. */ SPRN(balance, (uint32_t)(uintptr_t)(_pthread_self())); #endif if (narenas > 1) { #ifdef MALLOC_BALANCE unsigned ind; ind = PRN(balance, narenas_2pow); if ((ret = arenas[ind]) == NULL) { malloc_spin_lock(&arenas_lock); if ((ret = arenas[ind]) == NULL) ret = arenas_extend(ind); malloc_spin_unlock(&arenas_lock); } #else malloc_spin_lock(&arenas_lock); if ((ret = arenas[next_arena]) == NULL) ret = arenas_extend(next_arena); next_arena = (next_arena + 1) % narenas; malloc_spin_unlock(&arenas_lock); #endif } else ret = arenas[0]; arenas_map = ret; return (ret); } #endif static inline int arena_chunk_comp(arena_chunk_t *a, arena_chunk_t *b) { assert(a != NULL); assert(b != NULL); if ((uintptr_t)a < (uintptr_t)b) return (-1); else if (a == b) return (0); else return (1); } /* Generate red-black tree code for arena chunks. */ RB_GENERATE_STATIC(arena_chunk_tree_s, arena_chunk_s, link, arena_chunk_comp) static inline int arena_run_comp(arena_run_t *a, arena_run_t *b) { assert(a != NULL); assert(b != NULL); if ((uintptr_t)a < (uintptr_t)b) return (-1); else if (a == b) return (0); else return (1); } /* Generate red-black tree code for arena runs. */ RB_GENERATE_STATIC(arena_run_tree_s, arena_run_s, link, arena_run_comp) static inline void * arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin) { void *ret; unsigned i, mask, bit, regind; assert(run->magic == ARENA_RUN_MAGIC); assert(run->regs_minelm < bin->regs_mask_nelms); /* * Move the first check outside the loop, so that run->regs_minelm can * be updated unconditionally, without the possibility of updating it * multiple times. */ i = run->regs_minelm; mask = run->regs_mask[i]; if (mask != 0) { /* Usable allocation found. */ bit = ffs((int)mask) - 1; regind = ((i << (SIZEOF_INT_2POW + 3)) + bit); ret = (void *)(((uintptr_t)run) + bin->reg0_offset + (bin->reg_size * regind)); /* Clear bit. */ mask ^= (1U << bit); run->regs_mask[i] = mask; return (ret); } for (i++; i < bin->regs_mask_nelms; i++) { mask = run->regs_mask[i]; if (mask != 0) { /* Usable allocation found. */ bit = ffs((int)mask) - 1; regind = ((i << (SIZEOF_INT_2POW + 3)) + bit); ret = (void *)(((uintptr_t)run) + bin->reg0_offset + (bin->reg_size * regind)); /* Clear bit. */ mask ^= (1U << bit); run->regs_mask[i] = mask; /* * Make a note that nothing before this element * contains a free region. */ run->regs_minelm = i; /* Low payoff: + (mask == 0); */ return (ret); } } /* Not reached. */ assert(0); return (NULL); } static inline void arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size) { /* * To divide by a number D that is not a power of two we multiply * by (2^21 / D) and then right shift by 21 positions. * * X / D * * becomes * * (X * size_invs[(D >> QUANTUM_2POW_MIN) - 3]) >> SIZE_INV_SHIFT */ #define SIZE_INV_SHIFT 21 #define SIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << QUANTUM_2POW_MIN)) + 1) static const unsigned size_invs[] = { SIZE_INV(3), SIZE_INV(4), SIZE_INV(5), SIZE_INV(6), SIZE_INV(7), SIZE_INV(8), SIZE_INV(9), SIZE_INV(10), SIZE_INV(11), SIZE_INV(12),SIZE_INV(13), SIZE_INV(14), SIZE_INV(15), SIZE_INV(16),SIZE_INV(17), SIZE_INV(18), SIZE_INV(19), SIZE_INV(20),SIZE_INV(21), SIZE_INV(22), SIZE_INV(23), SIZE_INV(24),SIZE_INV(25), SIZE_INV(26), SIZE_INV(27), SIZE_INV(28),SIZE_INV(29), SIZE_INV(30), SIZE_INV(31) #if (QUANTUM_2POW_MIN < 4) , SIZE_INV(32), SIZE_INV(33), SIZE_INV(34), SIZE_INV(35), SIZE_INV(36), SIZE_INV(37), SIZE_INV(38), SIZE_INV(39), SIZE_INV(40), SIZE_INV(41), SIZE_INV(42), SIZE_INV(43), SIZE_INV(44), SIZE_INV(45), SIZE_INV(46), SIZE_INV(47), SIZE_INV(48), SIZE_INV(49), SIZE_INV(50), SIZE_INV(51), SIZE_INV(52), SIZE_INV(53), SIZE_INV(54), SIZE_INV(55), SIZE_INV(56), SIZE_INV(57), SIZE_INV(58), SIZE_INV(59), SIZE_INV(60), SIZE_INV(61), SIZE_INV(62), SIZE_INV(63) #endif }; unsigned diff, regind, elm, bit; assert(run->magic == ARENA_RUN_MAGIC); assert(((sizeof(size_invs)) / sizeof(unsigned)) + 3 >= (SMALL_MAX_DEFAULT >> QUANTUM_2POW_MIN)); /* * Avoid doing division with a variable divisor if possible. Using * actual division here can reduce allocator throughput by over 20%! */ diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run - bin->reg0_offset); if ((size & (size - 1)) == 0) { /* * log2_table allows fast division of a power of two in the * [1..128] range. * * (x / divisor) becomes (x >> log2_table[divisor - 1]). */ static const unsigned char log2_table[] = { 0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7 }; if (size <= 128) regind = (diff >> log2_table[size - 1]); else if (size <= 32768) regind = diff >> (8 + log2_table[(size >> 8) - 1]); else { /* * The page size is too large for us to use the lookup * table. Use real division. */ regind = diff / size; } } else if (size <= ((sizeof(size_invs) / sizeof(unsigned)) << QUANTUM_2POW_MIN) + 2) { regind = size_invs[(size >> QUANTUM_2POW_MIN) - 3] * diff; regind >>= SIZE_INV_SHIFT; } else { /* * size_invs isn't large enough to handle this size class, so * calculate regind using actual division. This only happens * if the user increases small_max via the 'S' runtime * configuration option. */ regind = diff / size; }; assert(diff == regind * size); assert(regind < bin->nregs); elm = regind >> (SIZEOF_INT_2POW + 3); if (elm < run->regs_minelm) run->regs_minelm = elm; bit = regind - (elm << (SIZEOF_INT_2POW + 3)); assert((run->regs_mask[elm] & (1U << bit)) == 0); run->regs_mask[elm] |= (1U << bit); #undef SIZE_INV #undef SIZE_INV_SHIFT } static void arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool zero) { arena_chunk_t *chunk; unsigned run_ind, map_offset, total_pages, need_pages, rem_pages; unsigned i; uint32_t pos_beg, pos_end; chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run); run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow); total_pages = chunk->map[run_ind].npages; need_pages = (size >> pagesize_2pow); assert(need_pages > 0); assert(need_pages <= total_pages); rem_pages = total_pages - need_pages; /* Split enough pages from the front of run to fit allocation size. */ map_offset = run_ind; pos_beg = chunk->map[map_offset].pos; pos_end = chunk->map[map_offset + total_pages - 1].pos; if (zero == false) { for (i = 0; i < need_pages; i++) { chunk->map[map_offset + i].npages = need_pages; chunk->map[map_offset + i].pos = i; } } else { /* * Handle first page specially, since we need to look for * POS_EMPTY rather than NPAGES_EMPTY. */ i = 0; if (chunk->map[map_offset + i].pos != POS_EMPTY) { memset((void *)((uintptr_t)chunk + ((map_offset + i) << pagesize_2pow)), 0, pagesize); } chunk->map[map_offset + i].npages = need_pages; chunk->map[map_offset + i].pos = i; /* Handle central pages. */ for (i++; i < need_pages - 1; i++) { if (chunk->map[map_offset + i].npages != NPAGES_EMPTY) { memset((void *)((uintptr_t)chunk + ((map_offset + i) << pagesize_2pow)), 0, pagesize); } chunk->map[map_offset + i].npages = need_pages; chunk->map[map_offset + i].pos = i; } /* * Handle last page specially, since we need to look for * POS_EMPTY rather than NPAGES_EMPTY. */ if (i < need_pages) { if (chunk->map[map_offset + i].npages != POS_EMPTY) { memset((void *)((uintptr_t)chunk + ((map_offset + i) << pagesize_2pow)), 0, pagesize); } chunk->map[map_offset + i].npages = need_pages; chunk->map[map_offset + i].pos = i; } } /* Keep track of trailing unused pages for later use. */ if (rem_pages > 0) { /* Update map for trailing pages. */ map_offset += need_pages; chunk->map[map_offset].npages = rem_pages; chunk->map[map_offset].pos = pos_beg; chunk->map[map_offset + rem_pages - 1].npages = rem_pages; chunk->map[map_offset + rem_pages - 1].pos = pos_end; } chunk->pages_used += need_pages; } static arena_chunk_t * arena_chunk_alloc(arena_t *arena) { arena_chunk_t *chunk; if (arena->spare != NULL) { chunk = arena->spare; arena->spare = NULL; RB_INSERT(arena_chunk_tree_s, &arena->chunks, chunk); } else { unsigned i; chunk = (arena_chunk_t *)chunk_alloc(chunksize); if (chunk == NULL) return (NULL); #ifdef MALLOC_STATS arena->stats.mapped += chunksize; #endif chunk->arena = arena; RB_INSERT(arena_chunk_tree_s, &arena->chunks, chunk); /* * Claim that no pages are in use, since the header is merely * overhead. */ chunk->pages_used = 0; chunk->max_frun_npages = chunk_npages - arena_chunk_header_npages; chunk->min_frun_ind = arena_chunk_header_npages; /* * Initialize enough of the map to support one maximal free run. */ i = arena_chunk_header_npages; chunk->map[i].npages = chunk_npages - arena_chunk_header_npages; chunk->map[i].pos = POS_EMPTY; /* Mark the free run's central pages as untouched. */ for (i++; i < chunk_npages - 1; i++) chunk->map[i].npages = NPAGES_EMPTY; /* Take care when (chunk_npages == 2). */ if (i < chunk_npages) { chunk->map[i].npages = chunk_npages - arena_chunk_header_npages; chunk->map[i].pos = POS_EMPTY; } } return (chunk); } static void arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk) { /* * Remove chunk from the chunk tree, regardless of whether this chunk * will be cached, so that the arena does not use it. */ RB_REMOVE(arena_chunk_tree_s, &chunk->arena->chunks, chunk); if (opt_hint == false) { if (arena->spare != NULL) { chunk_dealloc((void *)arena->spare, chunksize); #ifdef MALLOC_STATS arena->stats.mapped -= chunksize; #endif } arena->spare = chunk; } else { assert(arena->spare == NULL); chunk_dealloc((void *)chunk, chunksize); #ifdef MALLOC_STATS arena->stats.mapped -= chunksize; #endif } } static arena_run_t * arena_run_alloc(arena_t *arena, size_t size, bool zero) { arena_chunk_t *chunk; arena_run_t *run; unsigned need_npages, limit_pages, compl_need_npages; assert(size <= (chunksize - (arena_chunk_header_npages << pagesize_2pow))); assert((size & pagesize_mask) == 0); /* * Search through arena's chunks in address order for a free run that is * large enough. Look for the first fit. */ need_npages = (size >> pagesize_2pow); limit_pages = chunk_npages - arena_chunk_header_npages; compl_need_npages = limit_pages - need_npages; RB_FOREACH(chunk, arena_chunk_tree_s, &arena->chunks) { /* * Avoid searching this chunk if there are not enough * contiguous free pages for there to possibly be a large * enough free run. */ if (chunk->pages_used <= compl_need_npages && need_npages <= chunk->max_frun_npages) { arena_chunk_map_t *mapelm; unsigned i; unsigned max_frun_npages = 0; unsigned min_frun_ind = chunk_npages; assert(chunk->min_frun_ind >= arena_chunk_header_npages); for (i = chunk->min_frun_ind; i < chunk_npages;) { mapelm = &chunk->map[i]; if (mapelm->pos >= POS_EMPTY) { if (mapelm->npages >= need_npages) { run = (arena_run_t *) ((uintptr_t)chunk + (i << pagesize_2pow)); /* Update page map. */ arena_run_split(arena, run, size, zero); return (run); } if (mapelm->npages > max_frun_npages) { max_frun_npages = mapelm->npages; } if (i < min_frun_ind) { min_frun_ind = i; if (i < chunk->min_frun_ind) chunk->min_frun_ind = i; } } i += mapelm->npages; } /* * Search failure. Reset cached chunk->max_frun_npages. * chunk->min_frun_ind was already reset above (if * necessary). */ chunk->max_frun_npages = max_frun_npages; } } /* * No usable runs. Create a new chunk from which to allocate the run. */ chunk = arena_chunk_alloc(arena); if (chunk == NULL) return (NULL); run = (arena_run_t *)((uintptr_t)chunk + (arena_chunk_header_npages << pagesize_2pow)); /* Update page map. */ arena_run_split(arena, run, size, zero); return (run); } static void arena_run_dalloc(arena_t *arena, arena_run_t *run, size_t size) { arena_chunk_t *chunk; unsigned run_ind, run_pages; chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run); run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow); assert(run_ind >= arena_chunk_header_npages); assert(run_ind < (chunksize >> pagesize_2pow)); run_pages = (size >> pagesize_2pow); assert(run_pages == chunk->map[run_ind].npages); /* Subtract pages from count of pages used in chunk. */ chunk->pages_used -= run_pages; /* Mark run as deallocated. */ assert(chunk->map[run_ind].npages == run_pages); chunk->map[run_ind].pos = POS_FREE; assert(chunk->map[run_ind + run_pages - 1].npages == run_pages); chunk->map[run_ind + run_pages - 1].pos = POS_FREE; /* * Tell the kernel that we don't need the data in this run, but only if * requested via runtime configuration. */ if (opt_hint) madvise(run, size, MADV_FREE); /* Try to coalesce with neighboring runs. */ if (run_ind > arena_chunk_header_npages && chunk->map[run_ind - 1].pos >= POS_EMPTY) { unsigned prev_npages; /* Coalesce with previous run. */ prev_npages = chunk->map[run_ind - 1].npages; /* * The way run allocation currently works (lowest first fit), * it is impossible for a free run to have empty (untouched) * pages followed by dirty pages. If the run allocation policy * changes, then we will need to account for it here. */ assert(chunk->map[run_ind - 1].pos != POS_EMPTY); #if 0 if (prev_npages > 1 && chunk->map[run_ind - 1].pos == POS_EMPTY) chunk->map[run_ind - 1].npages = NPAGES_EMPTY; #endif run_ind -= prev_npages; assert(chunk->map[run_ind].npages == prev_npages); assert(chunk->map[run_ind].pos >= POS_EMPTY); run_pages += prev_npages; chunk->map[run_ind].npages = run_pages; assert(chunk->map[run_ind].pos >= POS_EMPTY); chunk->map[run_ind + run_pages - 1].npages = run_pages; assert(chunk->map[run_ind + run_pages - 1].pos >= POS_EMPTY); } if (run_ind + run_pages < chunk_npages && chunk->map[run_ind + run_pages].pos >= POS_EMPTY) { unsigned next_npages; /* Coalesce with next run. */ next_npages = chunk->map[run_ind + run_pages].npages; if (next_npages > 1 && chunk->map[run_ind + run_pages].pos == POS_EMPTY) chunk->map[run_ind + run_pages].npages = NPAGES_EMPTY; run_pages += next_npages; assert(chunk->map[run_ind + run_pages - 1].npages == next_npages); assert(chunk->map[run_ind + run_pages - 1].pos >= POS_EMPTY); chunk->map[run_ind].npages = run_pages; assert(chunk->map[run_ind].pos >= POS_EMPTY); chunk->map[run_ind + run_pages - 1].npages = run_pages; assert(chunk->map[run_ind + run_pages - 1].pos >= POS_EMPTY); } if (chunk->map[run_ind].npages > chunk->max_frun_npages) chunk->max_frun_npages = chunk->map[run_ind].npages; if (run_ind < chunk->min_frun_ind) chunk->min_frun_ind = run_ind; /* Deallocate chunk if it is now completely unused. */ if (chunk->pages_used == 0) arena_chunk_dealloc(arena, chunk); } static arena_run_t * arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin) { arena_run_t *run; unsigned i, remainder; /* Look for a usable run. */ if ((run = RB_MIN(arena_run_tree_s, &bin->runs)) != NULL) { /* run is guaranteed to have available space. */ RB_REMOVE(arena_run_tree_s, &bin->runs, run); #ifdef MALLOC_STATS bin->stats.reruns++; #endif return (run); } /* No existing runs have any space available. */ /* Allocate a new run. */ run = arena_run_alloc(arena, bin->run_size, false); if (run == NULL) return (NULL); /* Initialize run internals. */ run->bin = bin; for (i = 0; i < bin->regs_mask_nelms; i++) run->regs_mask[i] = UINT_MAX; remainder = bin->nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1); if (remainder != 0) { /* The last element has spare bits that need to be unset. */ run->regs_mask[i] = (UINT_MAX >> ((1U << (SIZEOF_INT_2POW + 3)) - remainder)); } run->regs_minelm = 0; run->nfree = bin->nregs; #ifdef MALLOC_DEBUG run->magic = ARENA_RUN_MAGIC; #endif #ifdef MALLOC_STATS bin->stats.nruns++; bin->stats.curruns++; if (bin->stats.curruns > bin->stats.highruns) bin->stats.highruns = bin->stats.curruns; #endif return (run); } /* bin->runcur must have space available before this function is called. */ static inline void * arena_bin_malloc_easy(arena_t *arena, arena_bin_t *bin, arena_run_t *run) { void *ret; assert(run->magic == ARENA_RUN_MAGIC); assert(run->nfree > 0); ret = arena_run_reg_alloc(run, bin); assert(ret != NULL); run->nfree--; return (ret); } /* Re-fill bin->runcur, then call arena_bin_malloc_easy(). */ static void * arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin) { bin->runcur = arena_bin_nonfull_run_get(arena, bin); if (bin->runcur == NULL) return (NULL); assert(bin->runcur->magic == ARENA_RUN_MAGIC); assert(bin->runcur->nfree > 0); return (arena_bin_malloc_easy(arena, bin, bin->runcur)); } /* * Calculate bin->run_size such that it meets the following constraints: * * *) bin->run_size >= min_run_size * *) bin->run_size <= arena_maxclass * *) bin->run_size <= RUN_MAX_SMALL * *) run header overhead <= RUN_MAX_OVRHD (or header overhead relaxed). * * bin->nregs, bin->regs_mask_nelms, and bin->reg0_offset are * also calculated here, since these settings are all interdependent. */ static size_t arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size) { size_t try_run_size, good_run_size; unsigned good_nregs, good_mask_nelms, good_reg0_offset; unsigned try_nregs, try_mask_nelms, try_reg0_offset; assert(min_run_size >= pagesize); assert(min_run_size <= arena_maxclass); assert(min_run_size <= RUN_MAX_SMALL); /* * Calculate known-valid settings before entering the run_size * expansion loop, so that the first part of the loop always copies * valid settings. * * The do..while loop iteratively reduces the number of regions until * the run header and the regions no longer overlap. A closed formula * would be quite messy, since there is an interdependency between the * header's mask length and the number of regions. */ try_run_size = min_run_size; try_nregs = ((try_run_size - sizeof(arena_run_t)) / bin->reg_size) + 1; /* Counter-act try_nregs-- in loop. */ do { try_nregs--; try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) + ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ? 1 : 0); try_reg0_offset = try_run_size - (try_nregs * bin->reg_size); } while (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1)) > try_reg0_offset); /* run_size expansion loop. */ do { /* * Copy valid settings before trying more aggressive settings. */ good_run_size = try_run_size; good_nregs = try_nregs; good_mask_nelms = try_mask_nelms; good_reg0_offset = try_reg0_offset; /* Try more aggressive settings. */ try_run_size += pagesize; try_nregs = ((try_run_size - sizeof(arena_run_t)) / bin->reg_size) + 1; /* Counter-act try_nregs-- in loop. */ do { try_nregs--; try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) + ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ? 1 : 0); try_reg0_offset = try_run_size - (try_nregs * bin->reg_size); } while (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1)) > try_reg0_offset); } while (try_run_size <= arena_maxclass && try_run_size <= RUN_MAX_SMALL && RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX && (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size); assert(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1)) <= good_reg0_offset); assert((good_mask_nelms << (SIZEOF_INT_2POW + 3)) >= good_nregs); /* Copy final settings. */ bin->run_size = good_run_size; bin->nregs = good_nregs; bin->regs_mask_nelms = good_mask_nelms; bin->reg0_offset = good_reg0_offset; return (good_run_size); } #ifdef MALLOC_BALANCE static inline void arena_lock_balance(arena_t *arena) { unsigned contention; contention = malloc_spin_lock(&arena->lock); if (narenas > 1) { /* * Calculate the exponentially averaged contention for this * arena. Due to integer math always rounding down, this value * decays somewhat faster then normal. */ arena->contention = (((uint64_t)arena->contention * (uint64_t)((1U << BALANCE_ALPHA_INV_2POW)-1)) + (uint64_t)contention) >> BALANCE_ALPHA_INV_2POW; if (arena->contention >= opt_balance_threshold) { uint32_t ind; arena->contention = 0; #ifdef MALLOC_STATS arena->stats.nbalance++; #endif ind = PRN(balance, narenas_2pow); if (arenas[ind] != NULL) arenas_map = arenas[ind]; else { malloc_spin_lock(&arenas_lock); if (arenas[ind] != NULL) arenas_map = arenas[ind]; else arenas_map = arenas_extend(ind); malloc_spin_unlock(&arenas_lock); } } } } #endif static void * arena_malloc(arena_t *arena, size_t size, bool zero) { void *ret; assert(arena != NULL); assert(arena->magic == ARENA_MAGIC); assert(size != 0); assert(QUANTUM_CEILING(size) <= arena_maxclass); if (size <= bin_maxclass) { arena_bin_t *bin; arena_run_t *run; /* Small allocation. */ if (size < small_min) { /* Tiny. */ size = pow2_ceil(size); bin = &arena->bins[ffs((int)(size >> (TINY_MIN_2POW + 1)))]; #if (!defined(NDEBUG) || defined(MALLOC_STATS)) /* * Bin calculation is always correct, but we may need * to fix size for the purposes of assertions and/or * stats accuracy. */ if (size < (1U << TINY_MIN_2POW)) size = (1U << TINY_MIN_2POW); #endif } else if (size <= small_max) { /* Quantum-spaced. */ size = QUANTUM_CEILING(size); bin = &arena->bins[ntbins + (size >> opt_quantum_2pow) - 1]; } else { /* Sub-page. */ size = pow2_ceil(size); bin = &arena->bins[ntbins + nqbins + (ffs((int)(size >> opt_small_max_2pow)) - 2)]; } assert(size == bin->reg_size); #ifdef MALLOC_BALANCE arena_lock_balance(arena); #else malloc_spin_lock(&arena->lock); #endif if ((run = bin->runcur) != NULL && run->nfree > 0) ret = arena_bin_malloc_easy(arena, bin, run); else ret = arena_bin_malloc_hard(arena, bin); if (ret == NULL) { malloc_spin_unlock(&arena->lock); return (NULL); } #ifdef MALLOC_STATS bin->stats.nrequests++; arena->stats.nmalloc_small++; arena->stats.allocated_small += size; #endif malloc_spin_unlock(&arena->lock); if (zero == false) { if (opt_junk) memset(ret, 0xa5, size); else if (opt_zero) memset(ret, 0, size); } else memset(ret, 0, size); } else { /* Large allocation. */ size = PAGE_CEILING(size); #ifdef MALLOC_BALANCE arena_lock_balance(arena); #else malloc_spin_lock(&arena->lock); #endif ret = (void *)arena_run_alloc(arena, size, zero); if (ret == NULL) { malloc_spin_unlock(&arena->lock); return (NULL); } #ifdef MALLOC_STATS arena->stats.nmalloc_large++; arena->stats.allocated_large += size; #endif malloc_spin_unlock(&arena->lock); if (zero == false) { if (opt_junk) memset(ret, 0xa5, size); else if (opt_zero) memset(ret, 0, size); } } return (ret); } static inline void arena_palloc_trim(arena_t *arena, arena_chunk_t *chunk, unsigned pageind, unsigned npages) { unsigned i; assert(npages > 0); /* * Modifiy the map such that arena_run_dalloc() sees the run as * separately allocated. */ for (i = 0; i < npages; i++) { chunk->map[pageind + i].npages = npages; chunk->map[pageind + i].pos = i; } arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)chunk + (pageind << pagesize_2pow)), npages << pagesize_2pow); } /* Only handles large allocations that require more than page alignment. */ static void * arena_palloc(arena_t *arena, size_t alignment, size_t size, size_t alloc_size) { void *ret; size_t offset; arena_chunk_t *chunk; unsigned pageind, i, npages; assert((size & pagesize_mask) == 0); assert((alignment & pagesize_mask) == 0); npages = size >> pagesize_2pow; #ifdef MALLOC_BALANCE arena_lock_balance(arena); #else malloc_spin_lock(&arena->lock); #endif ret = (void *)arena_run_alloc(arena, alloc_size, false); if (ret == NULL) { malloc_spin_unlock(&arena->lock); return (NULL); } chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ret); offset = (uintptr_t)ret & (alignment - 1); assert((offset & pagesize_mask) == 0); assert(offset < alloc_size); if (offset == 0) { pageind = (((uintptr_t)ret - (uintptr_t)chunk) >> pagesize_2pow); /* Update the map for the run to be kept. */ for (i = 0; i < npages; i++) { chunk->map[pageind + i].npages = npages; assert(chunk->map[pageind + i].pos == i); } /* Trim trailing space. */ arena_palloc_trim(arena, chunk, pageind + npages, (alloc_size - size) >> pagesize_2pow); } else { size_t leadsize, trailsize; leadsize = alignment - offset; ret = (void *)((uintptr_t)ret + leadsize); pageind = (((uintptr_t)ret - (uintptr_t)chunk) >> pagesize_2pow); /* Update the map for the run to be kept. */ for (i = 0; i < npages; i++) { chunk->map[pageind + i].npages = npages; chunk->map[pageind + i].pos = i; } /* Trim leading space. */ arena_palloc_trim(arena, chunk, pageind - (leadsize >> pagesize_2pow), leadsize >> pagesize_2pow); trailsize = alloc_size - leadsize - size; if (trailsize != 0) { /* Trim trailing space. */ assert(trailsize < alloc_size); arena_palloc_trim(arena, chunk, pageind + npages, trailsize >> pagesize_2pow); } } #ifdef MALLOC_STATS arena->stats.nmalloc_large++; arena->stats.allocated_large += size; #endif malloc_spin_unlock(&arena->lock); if (opt_junk) memset(ret, 0xa5, size); else if (opt_zero) memset(ret, 0, size); return (ret); } /* Return the size of the allocation pointed to by ptr. */ static size_t arena_salloc(const void *ptr) { size_t ret; arena_chunk_t *chunk; arena_chunk_map_t *mapelm; unsigned pageind; assert(ptr != NULL); assert(CHUNK_ADDR2BASE(ptr) != ptr); /* * No arena data structures that we query here can change in a way that * affects this function, so we don't need to lock. */ chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow); mapelm = &chunk->map[pageind]; if (mapelm->pos != 0 || ptr != (void *)(((uintptr_t)chunk) + (pageind << pagesize_2pow))) { arena_run_t *run; pageind -= mapelm->pos; run = (arena_run_t *)((uintptr_t)chunk + (pageind << pagesize_2pow)); assert(run->magic == ARENA_RUN_MAGIC); ret = run->bin->reg_size; } else ret = mapelm->npages << pagesize_2pow; return (ret); } static void * arena_ralloc(void *ptr, size_t size, size_t oldsize) { void *ret; /* Avoid moving the allocation if the size class would not change. */ if (size < small_min) { if (oldsize < small_min && ffs((int)(pow2_ceil(size) >> (TINY_MIN_2POW + 1))) == ffs((int)(pow2_ceil(oldsize) >> (TINY_MIN_2POW + 1)))) goto IN_PLACE; } else if (size <= small_max) { if (oldsize >= small_min && oldsize <= small_max && (QUANTUM_CEILING(size) >> opt_quantum_2pow) == (QUANTUM_CEILING(oldsize) >> opt_quantum_2pow)) goto IN_PLACE; } else { /* * We make no attempt to resize runs here, though it would be * possible to do so. */ if (oldsize > small_max && PAGE_CEILING(size) == oldsize) goto IN_PLACE; } /* * If we get here, then size and oldsize are different enough that we * need to use a different size class. In that case, fall back to * allocating new space and copying. */ ret = arena_malloc(choose_arena(), size, false); if (ret == NULL) return (NULL); /* Junk/zero-filling were already done by arena_malloc(). */ if (size < oldsize) memcpy(ret, ptr, size); else memcpy(ret, ptr, oldsize); idalloc(ptr); return (ret); IN_PLACE: if (opt_junk && size < oldsize) memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize - size); else if (opt_zero && size > oldsize) memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize); return (ptr); } static inline void arena_dalloc_small(arena_t *arena, arena_chunk_t *chunk, void *ptr, unsigned pageind, arena_chunk_map_t *mapelm) { arena_run_t *run; arena_bin_t *bin; size_t size; pageind -= mapelm->pos; run = (arena_run_t *)((uintptr_t)chunk + (pageind << pagesize_2pow)); assert(run->magic == ARENA_RUN_MAGIC); bin = run->bin; size = bin->reg_size; if (opt_junk) memset(ptr, 0x5a, size); arena_run_reg_dalloc(run, bin, ptr, size); run->nfree++; if (run->nfree == bin->nregs) { /* Deallocate run. */ if (run == bin->runcur) bin->runcur = NULL; else if (bin->nregs != 1) { /* * This block's conditional is necessary because if the * run only contains one region, then it never gets * inserted into the non-full runs tree. */ RB_REMOVE(arena_run_tree_s, &bin->runs, run); } #ifdef MALLOC_DEBUG run->magic = 0; #endif arena_run_dalloc(arena, run, bin->run_size); #ifdef MALLOC_STATS bin->stats.curruns--; #endif } else if (run->nfree == 1 && run != bin->runcur) { /* * Make sure that bin->runcur always refers to the lowest * non-full run, if one exists. */ if (bin->runcur == NULL) bin->runcur = run; else if ((uintptr_t)run < (uintptr_t)bin->runcur) { /* Switch runcur. */ if (bin->runcur->nfree > 0) { /* Insert runcur. */ RB_INSERT(arena_run_tree_s, &bin->runs, bin->runcur); } bin->runcur = run; } else RB_INSERT(arena_run_tree_s, &bin->runs, run); } #ifdef MALLOC_STATS arena->stats.allocated_small -= size; arena->stats.ndalloc_small++; #endif } #ifdef MALLOC_LAZY_FREE static inline void arena_dalloc_lazy(arena_t *arena, arena_chunk_t *chunk, void *ptr, unsigned pageind, arena_chunk_map_t *mapelm) { void **free_cache = arena->free_cache; unsigned i, slot; if (!__isthreaded || opt_lazy_free_2pow < 0) { malloc_spin_lock(&arena->lock); arena_dalloc_small(arena, chunk, ptr, pageind, mapelm); malloc_spin_unlock(&arena->lock); return; } for (i = 0; i < LAZY_FREE_NPROBES; i++) { slot = PRN(lazy_free, opt_lazy_free_2pow); if (atomic_cmpset_ptr((uintptr_t *)&free_cache[slot], (uintptr_t)NULL, (uintptr_t)ptr)) { return; } } malloc_spin_lock(&arena->lock); arena_dalloc_small(arena, chunk, ptr, pageind, mapelm); /* * Check whether another thread already cleared the cache. It is * possible that another thread cleared the cache *and* this slot was * already refilled, which could result in a mostly fruitless cache * sweep, but such a sequence of events causes no correctness issues. */ if ((ptr = (void *)atomic_readandclear_ptr( (uintptr_t *)&free_cache[slot])) != NULL) { unsigned lazy_free_mask; /* * Clear the cache, since we failed to find a slot. It is * possible that other threads will continue to insert objects * into the cache while this one sweeps, but that is okay, * since on average the cache is still swept with the same * frequency. */ /* Handle pointer at current slot. */ chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow); mapelm = &chunk->map[pageind]; arena_dalloc_small(arena, chunk, ptr, pageind, mapelm); /* Sweep remainder of slots. */ lazy_free_mask = (1U << opt_lazy_free_2pow) - 1; for (i = (slot + 1) & lazy_free_mask; i != slot; i = (i + 1) & lazy_free_mask) { ptr = (void *)atomic_readandclear_ptr( (uintptr_t *)&free_cache[i]); if (ptr != NULL) { chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow); mapelm = &chunk->map[pageind]; arena_dalloc_small(arena, chunk, ptr, pageind, mapelm); } } } malloc_spin_unlock(&arena->lock); } #endif static void arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr) { unsigned pageind; arena_chunk_map_t *mapelm; assert(arena != NULL); assert(arena->magic == ARENA_MAGIC); assert(chunk->arena == arena); assert(ptr != NULL); assert(CHUNK_ADDR2BASE(ptr) != ptr); pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow); mapelm = &chunk->map[pageind]; if (mapelm->pos != 0 || ptr != (void *)(((uintptr_t)chunk) + (pageind << pagesize_2pow))) { /* Small allocation. */ #ifdef MALLOC_LAZY_FREE arena_dalloc_lazy(arena, chunk, ptr, pageind, mapelm); #else malloc_spin_lock(&arena->lock); arena_dalloc_small(arena, chunk, ptr, pageind, mapelm); malloc_spin_unlock(&arena->lock); #endif } else { size_t size; /* Large allocation. */ size = mapelm->npages << pagesize_2pow; assert((((uintptr_t)ptr) & pagesize_mask) == 0); if (opt_junk) memset(ptr, 0x5a, size); malloc_spin_lock(&arena->lock); arena_run_dalloc(arena, (arena_run_t *)ptr, size); #ifdef MALLOC_STATS arena->stats.allocated_large -= size; arena->stats.ndalloc_large++; #endif malloc_spin_unlock(&arena->lock); } } static bool arena_new(arena_t *arena) { unsigned i; arena_bin_t *bin; size_t pow2_size, prev_run_size; if (malloc_spin_init(&arena->lock)) return (true); #ifdef MALLOC_STATS memset(&arena->stats, 0, sizeof(arena_stats_t)); #endif /* Initialize chunks. */ RB_INIT(&arena->chunks); arena->spare = NULL; #ifdef MALLOC_BALANCE arena->contention = 0; #endif #ifdef MALLOC_LAZY_FREE if (opt_lazy_free_2pow >= 0) { arena->free_cache = (void **) base_alloc(sizeof(void *) * (1U << opt_lazy_free_2pow)); if (arena->free_cache == NULL) return (true); memset(arena->free_cache, 0, sizeof(void *) * (1U << opt_lazy_free_2pow)); } else arena->free_cache = NULL; #endif /* Initialize bins. */ prev_run_size = pagesize; /* (2^n)-spaced tiny bins. */ for (i = 0; i < ntbins; i++) { bin = &arena->bins[i]; bin->runcur = NULL; RB_INIT(&bin->runs); bin->reg_size = (1U << (TINY_MIN_2POW + i)); prev_run_size = arena_bin_run_size_calc(bin, prev_run_size); #ifdef MALLOC_STATS memset(&bin->stats, 0, sizeof(malloc_bin_stats_t)); #endif } /* Quantum-spaced bins. */ for (; i < ntbins + nqbins; i++) { bin = &arena->bins[i]; bin->runcur = NULL; RB_INIT(&bin->runs); bin->reg_size = quantum * (i - ntbins + 1); pow2_size = pow2_ceil(quantum * (i - ntbins + 1)); prev_run_size = arena_bin_run_size_calc(bin, prev_run_size); #ifdef MALLOC_STATS memset(&bin->stats, 0, sizeof(malloc_bin_stats_t)); #endif } /* (2^n)-spaced sub-page bins. */ for (; i < ntbins + nqbins + nsbins; i++) { bin = &arena->bins[i]; bin->runcur = NULL; RB_INIT(&bin->runs); bin->reg_size = (small_max << (i - (ntbins + nqbins) + 1)); prev_run_size = arena_bin_run_size_calc(bin, prev_run_size); #ifdef MALLOC_STATS memset(&bin->stats, 0, sizeof(malloc_bin_stats_t)); #endif } #ifdef MALLOC_DEBUG arena->magic = ARENA_MAGIC; #endif return (false); } /* Create a new arena and insert it into the arenas array at index ind. */ static arena_t * arenas_extend(unsigned ind) { arena_t *ret; /* Allocate enough space for trailing bins. */ ret = (arena_t *)base_alloc(sizeof(arena_t) + (sizeof(arena_bin_t) * (ntbins + nqbins + nsbins - 1))); if (ret != NULL && arena_new(ret) == false) { arenas[ind] = ret; return (ret); } /* Only reached if there is an OOM error. */ /* * OOM here is quite inconvenient to propagate, since dealing with it * would require a check for failure in the fast path. Instead, punt * by using arenas[0]. In practice, this is an extremely unlikely * failure. */ _malloc_message(_getprogname(), ": (malloc) Error initializing arena\n", "", ""); if (opt_abort) abort(); return (arenas[0]); } /* * End arena. */ /******************************************************************************/ /* * Begin general internal functions. */ static void * huge_malloc(size_t size, bool zero) { void *ret; size_t csize; chunk_node_t *node; /* Allocate one or more contiguous chunks for this request. */ csize = CHUNK_CEILING(size); if (csize == 0) { /* size is large enough to cause size_t wrap-around. */ return (NULL); } /* Allocate a chunk node with which to track the chunk. */ node = base_chunk_node_alloc(); if (node == NULL) return (NULL); ret = chunk_alloc(csize); if (ret == NULL) { base_chunk_node_dealloc(node); return (NULL); } /* Insert node into huge. */ node->chunk = ret; node->size = csize; malloc_mutex_lock(&chunks_mtx); RB_INSERT(chunk_tree_s, &huge, node); #ifdef MALLOC_STATS huge_nmalloc++; huge_allocated += csize; #endif malloc_mutex_unlock(&chunks_mtx); if (zero == false) { if (opt_junk) memset(ret, 0xa5, csize); else if (opt_zero) memset(ret, 0, csize); } return (ret); } /* Only handles large allocations that require more than chunk alignment. */ static void * huge_palloc(size_t alignment, size_t size) { void *ret; size_t alloc_size, chunk_size, offset; chunk_node_t *node; /* * This allocation requires alignment that is even larger than chunk * alignment. This means that huge_malloc() isn't good enough. * * Allocate almost twice as many chunks as are demanded by the size or * alignment, in order to assure the alignment can be achieved, then * unmap leading and trailing chunks. */ assert(alignment >= chunksize); chunk_size = CHUNK_CEILING(size); if (size >= alignment) alloc_size = chunk_size + alignment - chunksize; else alloc_size = (alignment << 1) - chunksize; /* Allocate a chunk node with which to track the chunk. */ node = base_chunk_node_alloc(); if (node == NULL) return (NULL); ret = chunk_alloc(alloc_size); if (ret == NULL) { base_chunk_node_dealloc(node); return (NULL); } offset = (uintptr_t)ret & (alignment - 1); assert((offset & chunksize_mask) == 0); assert(offset < alloc_size); if (offset == 0) { /* Trim trailing space. */ chunk_dealloc((void *)((uintptr_t)ret + chunk_size), alloc_size - chunk_size); } else { size_t trailsize; /* Trim leading space. */ chunk_dealloc(ret, alignment - offset); ret = (void *)((uintptr_t)ret + (alignment - offset)); trailsize = alloc_size - (alignment - offset) - chunk_size; if (trailsize != 0) { /* Trim trailing space. */ assert(trailsize < alloc_size); chunk_dealloc((void *)((uintptr_t)ret + chunk_size), trailsize); } } /* Insert node into huge. */ node->chunk = ret; node->size = chunk_size; malloc_mutex_lock(&chunks_mtx); RB_INSERT(chunk_tree_s, &huge, node); #ifdef MALLOC_STATS huge_nmalloc++; huge_allocated += chunk_size; #endif malloc_mutex_unlock(&chunks_mtx); if (opt_junk) memset(ret, 0xa5, chunk_size); else if (opt_zero) memset(ret, 0, chunk_size); return (ret); } static void * huge_ralloc(void *ptr, size_t size, size_t oldsize) { void *ret; /* Avoid moving the allocation if the size class would not change. */ if (oldsize > arena_maxclass && CHUNK_CEILING(size) == CHUNK_CEILING(oldsize)) { if (opt_junk && size < oldsize) { memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize - size); } else if (opt_zero && size > oldsize) { memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize); } return (ptr); } /* * If we get here, then size and oldsize are different enough that we * need to use a different size class. In that case, fall back to * allocating new space and copying. */ ret = huge_malloc(size, false); if (ret == NULL) return (NULL); if (CHUNK_ADDR2BASE(ptr) == ptr) { /* The old allocation is a chunk. */ if (size < oldsize) memcpy(ret, ptr, size); else memcpy(ret, ptr, oldsize); } else { /* The old allocation is a region. */ assert(oldsize < size); memcpy(ret, ptr, oldsize); } idalloc(ptr); return (ret); } static void huge_dalloc(void *ptr) { chunk_node_t key; chunk_node_t *node; malloc_mutex_lock(&chunks_mtx); /* Extract from tree of huge allocations. */ key.chunk = ptr; node = RB_FIND(chunk_tree_s, &huge, &key); assert(node != NULL); assert(node->chunk == ptr); RB_REMOVE(chunk_tree_s, &huge, node); #ifdef MALLOC_STATS huge_ndalloc++; huge_allocated -= node->size; #endif malloc_mutex_unlock(&chunks_mtx); /* Unmap chunk. */ #ifdef 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, false); else ret = huge_malloc(size, false); return (ret); } static void * ipalloc(size_t alignment, size_t size) { void *ret; size_t ceil_size; /* * Round size up to the nearest multiple of alignment. * * This done, we can take advantage of the fact that for each small * size class, every object is aligned at the smallest power of two * that is non-zero in the base two representation of the size. For * example: * * Size | Base 2 | Minimum alignment * -----+----------+------------------ * 96 | 1100000 | 32 * 144 | 10100000 | 32 * 192 | 11000000 | 64 * * Depending on runtime settings, it is possible that arena_malloc() * will further round up to a power of two, but that never causes * correctness issues. */ ceil_size = (size + (alignment - 1)) & (-alignment); /* * (ceil_size < size) protects against the combination of maximal * alignment and size greater than maximal alignment. */ if (ceil_size < size) { /* size_t overflow. */ return (NULL); } if (ceil_size <= pagesize || (alignment <= pagesize && ceil_size <= arena_maxclass)) ret = arena_malloc(choose_arena(), ceil_size, false); else { size_t run_size; /* * We can't achieve sub-page alignment, so round up alignment * permanently; it makes later calculations simpler. */ alignment = PAGE_CEILING(alignment); ceil_size = PAGE_CEILING(size); /* * (ceil_size < size) protects against very large sizes within * pagesize of SIZE_T_MAX. * * (ceil_size + alignment < ceil_size) protects against the * combination of maximal alignment and ceil_size large enough * to cause overflow. This is similar to the first overflow * check above, but it needs to be repeated due to the new * ceil_size value, which may now be *equal* to maximal * alignment, whereas before we only detected overflow if the * original size was *greater* than maximal alignment. */ if (ceil_size < size || ceil_size + alignment < ceil_size) { /* size_t overflow. */ return (NULL); } /* * Calculate the size of the over-size run that arena_palloc() * would need to allocate in order to guarantee the alignment. */ if (ceil_size >= alignment) run_size = ceil_size + alignment - pagesize; else { /* * It is possible that (alignment << 1) will cause * overflow, but it doesn't matter because we also * subtract pagesize, which in the case of overflow * leaves us with a very large run_size. That causes * the first conditional below to fail, which means * that the bogus run_size value never gets used for * anything important. */ run_size = (alignment << 1) - pagesize; } if (run_size <= arena_maxclass) { ret = arena_palloc(choose_arena(), alignment, ceil_size, run_size); } else if (alignment <= chunksize) ret = huge_malloc(ceil_size, false); else ret = huge_palloc(alignment, ceil_size); } assert(((uintptr_t)ret & (alignment - 1)) == 0); return (ret); } static void * icalloc(size_t size) { void *ret; if (size <= arena_maxclass) ret = arena_malloc(choose_arena(), size, true); else ret = huge_malloc(size, true); return (ret); } static size_t isalloc(const void *ptr) { size_t ret; arena_chunk_t *chunk; assert(ptr != NULL); chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); if (chunk != ptr) { /* Region. */ assert(chunk->arena->magic == ARENA_MAGIC); ret = arena_salloc(ptr); } else { chunk_node_t *node, key; /* Chunk (huge allocation). */ malloc_mutex_lock(&chunks_mtx); /* Extract from tree of huge allocations. */ key.chunk = __DECONST(void *, ptr); node = RB_FIND(chunk_tree_s, &huge, &key); assert(node != NULL); ret = node->size; malloc_mutex_unlock(&chunks_mtx); } return (ret); } static void * iralloc(void *ptr, size_t size) { void *ret; size_t oldsize; assert(ptr != NULL); assert(size != 0); oldsize = isalloc(ptr); if (size <= arena_maxclass) ret = arena_ralloc(ptr, size, oldsize); else ret = huge_ralloc(ptr, size, oldsize); return (ret); } static void idalloc(void *ptr) { arena_chunk_t *chunk; assert(ptr != NULL); chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); if (chunk != ptr) { /* Region. */ arena_dalloc(chunk->arena, chunk, ptr); } else huge_dalloc(ptr); } static void malloc_print_stats(void) { if (opt_print_stats) { char s[UMAX2S_BUFSIZE]; _malloc_message("___ Begin malloc statistics ___\n", "", "", ""); _malloc_message("Assertions ", #ifdef NDEBUG "disabled", #else "enabled", #endif "\n", ""); _malloc_message("Boolean MALLOC_OPTIONS: ", opt_abort ? "A" : "a", opt_junk ? "J" : "j", opt_hint ? "H" : "h"); _malloc_message(opt_utrace ? "PU" : "Pu", opt_sysv ? "V" : "v", opt_xmalloc ? "X" : "x", opt_zero ? "Z\n" : "z\n"); _malloc_message("CPUs: ", umax2s(ncpus, s), "\n", ""); _malloc_message("Max arenas: ", umax2s(narenas, s), "\n", ""); #ifdef MALLOC_LAZY_FREE if (opt_lazy_free_2pow >= 0) { _malloc_message("Lazy free slots: ", umax2s(1U << opt_lazy_free_2pow, s), "\n", ""); } else _malloc_message("Lazy free slots: 0\n", "", "", ""); #endif #ifdef MALLOC_BALANCE _malloc_message("Arena balance threshold: ", umax2s(opt_balance_threshold, s), "\n", ""); #endif _malloc_message("Pointer size: ", umax2s(sizeof(void *), s), "\n", ""); _malloc_message("Quantum size: ", umax2s(quantum, s), "\n", ""); _malloc_message("Max small size: ", umax2s(small_max, s), "\n", ""); _malloc_message("Chunk size: ", umax2s(chunksize, s), "", ""); _malloc_message(" (2^", umax2s(opt_chunk_2pow, s), ")\n", ""); #ifdef MALLOC_STATS { size_t allocated, mapped; #ifdef MALLOC_BALANCE uint64_t nbalance = 0; #endif unsigned i; arena_t *arena; /* Calculate and print allocated/mapped stats. */ /* arenas. */ for (i = 0, allocated = 0; i < narenas; i++) { if (arenas[i] != NULL) { malloc_spin_lock(&arenas[i]->lock); allocated += arenas[i]->stats.allocated_small; allocated += arenas[i]->stats.allocated_large; #ifdef MALLOC_BALANCE nbalance += arenas[i]->stats.nbalance; #endif malloc_spin_unlock(&arenas[i]->lock); } } /* huge/base. */ malloc_mutex_lock(&chunks_mtx); allocated += huge_allocated; mapped = stats_chunks.curchunks * chunksize; malloc_mutex_unlock(&chunks_mtx); malloc_mutex_lock(&base_mtx); mapped += base_mapped; malloc_mutex_unlock(&base_mtx); malloc_printf("Allocated: %zu, mapped: %zu\n", allocated, mapped); #ifdef MALLOC_BALANCE malloc_printf("Arena balance reassignments: %llu\n", nbalance); #endif /* Print chunk stats. */ { chunk_stats_t chunks_stats; malloc_mutex_lock(&chunks_mtx); chunks_stats = stats_chunks; malloc_mutex_unlock(&chunks_mtx); malloc_printf("chunks: nchunks " "highchunks curchunks\n"); malloc_printf(" %13llu%13lu%13lu\n", chunks_stats.nchunks, chunks_stats.highchunks, chunks_stats.curchunks); } /* Print chunk stats. */ malloc_printf( "huge: nmalloc ndalloc allocated\n"); malloc_printf(" %12llu %12llu %12zu\n", huge_nmalloc, huge_ndalloc, huge_allocated); /* Print stats for each arena. */ for (i = 0; i < narenas; i++) { arena = arenas[i]; if (arena != NULL) { malloc_printf( "\narenas[%u]:\n", i); malloc_spin_lock(&arena->lock); stats_print(arena); malloc_spin_unlock(&arena->lock); } } } #endif /* #ifdef MALLOC_STATS */ _malloc_message("--- End malloc statistics ---\n", "", "", ""); } } /* * FreeBSD's pthreads implementation calls malloc(3), so the malloc * implementation has to take pains to avoid infinite recursion during * initialization. */ static inline bool malloc_init(void) { if (malloc_initialized == false) return (malloc_init_hard()); return (false); } static bool malloc_init_hard(void) { unsigned i, 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; } } #ifdef MALLOC_LAZY_FREE if (ncpus == 1) opt_lazy_free_2pow = -1; #endif /* Get page size. */ { long result; result = sysconf(_SC_PAGESIZE); assert(result != -1); pagesize = (unsigned) result; /* * We assume that pagesize is a power of 2 when calculating * pagesize_mask and pagesize_2pow. */ assert(((result - 1) & result) == 0); pagesize_mask = result - 1; pagesize_2pow = ffs((int)result) - 1; } for (i = 0; i < 3; i++) { /* 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 '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 'h': opt_hint = false; break; case 'H': opt_hint = true; break; case 'j': opt_junk = false; break; case 'J': opt_junk = true; break; case 'k': /* * Chunks always require at least one header * page, so chunks can never be smaller than * two pages. */ if (opt_chunk_2pow > pagesize_2pow + 1) opt_chunk_2pow--; break; case 'K': /* * There must be fewer pages in a chunk than * can be recorded by the pos field of * arena_chunk_map_t, in order to make * POS_EMPTY/POS_FREE special. */ if (opt_chunk_2pow - pagesize_2pow < (sizeof(uint32_t) << 3) - 1) opt_chunk_2pow++; break; case 'l': #ifdef MALLOC_LAZY_FREE if (opt_lazy_free_2pow >= 0) opt_lazy_free_2pow--; #endif break; case 'L': #ifdef MALLOC_LAZY_FREE if (ncpus > 1) opt_lazy_free_2pow++; #endif break; case '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"); } } } } /* Take care to call atexit() only once. */ if (opt_print_stats) { /* Print statistics at exit. */ atexit(malloc_print_stats); } /* Set variables according to the value of opt_small_max_2pow. */ if (opt_small_max_2pow < opt_quantum_2pow) opt_small_max_2pow = opt_quantum_2pow; small_max = (1U << opt_small_max_2pow); /* Set bin-related variables. */ bin_maxclass = (pagesize >> 1); assert(opt_quantum_2pow >= TINY_MIN_2POW); ntbins = opt_quantum_2pow - TINY_MIN_2POW; assert(ntbins <= opt_quantum_2pow); nqbins = (small_max >> opt_quantum_2pow); nsbins = pagesize_2pow - opt_small_max_2pow - 1; /* Set variables according to the value of opt_quantum_2pow. */ quantum = (1U << opt_quantum_2pow); quantum_mask = quantum - 1; if (ntbins > 0) small_min = (quantum >> 1) + 1; else small_min = 1; assert(small_min <= quantum); /* Set variables according to the value of opt_chunk_2pow. */ chunksize = (1LU << opt_chunk_2pow); chunksize_mask = chunksize - 1; chunk_npages = (chunksize >> pagesize_2pow); { unsigned header_size; header_size = sizeof(arena_chunk_t) + (sizeof(arena_chunk_map_t) * (chunk_npages - 1)); arena_chunk_header_npages = (header_size >> pagesize_2pow); if ((header_size & pagesize_mask) != 0) arena_chunk_header_npages++; } arena_maxclass = chunksize - (arena_chunk_header_npages << pagesize_2pow); #ifdef MALLOC_LAZY_FREE /* * Make sure that allocating the free_cache does not exceed the limits * of what base_alloc() can handle. */ while ((sizeof(void *) << opt_lazy_free_2pow) > chunksize) opt_lazy_free_2pow--; #endif UTRACE(0, 0, 0); #ifdef MALLOC_STATS memset(&stats_chunks, 0, sizeof(chunk_stats_t)); #endif /* Various sanity checks that regard configuration. */ assert(quantum >= sizeof(void *)); assert(quantum <= pagesize); assert(chunksize >= pagesize); assert(quantum * 4 <= chunksize); /* Initialize chunks data. */ malloc_mutex_init(&chunks_mtx); RB_INIT(&huge); #ifdef 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_mapped = 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_pages_alloc(0); #endif base_chunk_nodes = NULL; malloc_mutex_init(&base_mtx); if (ncpus > 1) { /* * For SMP systems, create four times as many arenas as there * are CPUs by default. */ opt_narenas_lshift += 2; } /* Determine how many arenas to use. */ narenas = ncpus; if (opt_narenas_lshift > 0) { if ((narenas << opt_narenas_lshift) > narenas) narenas <<= opt_narenas_lshift; /* * Make sure not to exceed the limits of what base_alloc() can * handle. */ if (narenas * sizeof(arena_t *) > chunksize) narenas = chunksize / sizeof(arena_t *); } else if (opt_narenas_lshift < 0) { if ((narenas >> -opt_narenas_lshift) < narenas) narenas >>= -opt_narenas_lshift; /* Make sure there is at least one arena. */ if (narenas == 0) narenas = 1; } #ifdef MALLOC_BALANCE assert(narenas != 0); for (narenas_2pow = 0; (narenas >> (narenas_2pow + 1)) != 0; narenas_2pow++); #endif #ifdef NO_TLS if (narenas > 1) { static const unsigned primes[] = {1, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263}; unsigned nprimes, parenas; /* * Pick a prime number of hash arenas that is more than narenas * so that direct hashing of pthread_self() pointers tends to * spread allocations evenly among the arenas. */ assert((narenas & 1) == 0); /* narenas must be even. */ nprimes = (sizeof(primes) >> SIZEOF_INT_2POW); parenas = primes[nprimes - 1]; /* In case not enough primes. */ for (i = 1; i < nprimes; i++) { if (primes[i] > narenas) { parenas = primes[i]; break; } } narenas = parenas; } #endif #ifndef NO_TLS # ifndef MALLOC_BALANCE next_arena = 0; # endif #endif /* Allocate and initialize arenas. */ arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas); if (arenas == NULL) { malloc_mutex_unlock(&init_lock); return (true); } /* * Zero the array. In practice, this should always be pre-zeroed, * since it was just mmap()ed, but let's be sure. */ memset(arenas, 0, sizeof(arena_t *) * narenas); /* * Initialize one arena here. The rest are lazily created in * choose_arena_hard(). */ arenas_extend(0); if (arenas[0] == NULL) { malloc_mutex_unlock(&init_lock); return (true); } #ifndef NO_TLS /* * Assign the initial arena to the initial thread, in order to avoid * spurious creation of an extra arena if the application switches to * threaded mode. */ arenas_map = arenas[0]; #endif /* * Seed here for the initial thread, since choose_arena_hard() is only * called for other threads. The seed values don't really matter. */ #ifdef MALLOC_LAZY_FREE SPRN(lazy_free, 42); #endif #ifdef MALLOC_BALANCE SPRN(balance, 42); #endif malloc_spin_init(&arenas_lock); malloc_initialized = true; malloc_mutex_unlock(&init_lock); return (false); } /* * End general internal functions. */ /******************************************************************************/ /* * Begin malloc(3)-compatible functions. */ void * malloc(size_t size) { void *ret; if (malloc_init()) { ret = NULL; goto RETURN; } if (size == 0) { if (opt_sysv == false) size = 1; else { ret = NULL; goto RETURN; } } ret = imalloc(size); RETURN: if (ret == NULL) { if (opt_xmalloc) { _malloc_message(_getprogname(), ": (malloc) Error in malloc(): out of memory\n", "", ""); abort(); } errno = ENOMEM; } UTRACE(0, size, ret); return (ret); } int posix_memalign(void **memptr, size_t alignment, size_t size) { int ret; void *result; if (malloc_init()) result = NULL; else { /* Make sure that alignment is a large enough power of 2. */ if (((alignment - 1) & alignment) != 0 || alignment < sizeof(void *)) { if (opt_xmalloc) { _malloc_message(_getprogname(), ": (malloc) Error in posix_memalign(): " "invalid alignment\n", "", ""); abort(); } result = NULL; ret = EINVAL; goto RETURN; } result = ipalloc(alignment, size); } if (result == NULL) { if (opt_xmalloc) { _malloc_message(_getprogname(), ": (malloc) Error in posix_memalign(): out of memory\n", "", ""); abort(); } ret = ENOMEM; goto RETURN; } *memptr = result; ret = 0; RETURN: UTRACE(0, size, result); return (ret); } void * calloc(size_t num, size_t size) { void *ret; size_t num_size; if (malloc_init()) { num_size = 0; ret = NULL; goto RETURN; } num_size = num * size; if (num_size == 0) { if ((opt_sysv == false) && ((num == 0) || (size == 0))) num_size = 1; else { ret = NULL; goto RETURN; } /* * Try to avoid division here. We know that it isn't possible to * overflow during multiplication if neither operand uses any of the * most significant half of the bits in a size_t. */ } else if (((num | size) & (SIZE_T_MAX << (sizeof(size_t) << 2))) && (num_size / size != num)) { /* size_t overflow. */ ret = NULL; goto RETURN; } ret = icalloc(num_size); RETURN: if (ret == NULL) { if (opt_xmalloc) { _malloc_message(_getprogname(), ": (malloc) Error in calloc(): out of memory\n", "", ""); abort(); } errno = ENOMEM; } UTRACE(0, num_size, ret); return (ret); } void * realloc(void *ptr, size_t size) { void *ret; if (size == 0) { if (opt_sysv == false) size = 1; else { if (ptr != NULL) idalloc(ptr); ret = NULL; goto RETURN; } } if (ptr != NULL) { assert(malloc_initialized); ret = iralloc(ptr, size); if (ret == NULL) { if (opt_xmalloc) { _malloc_message(_getprogname(), ": (malloc) Error in realloc(): out of " "memory\n", "", ""); abort(); } errno = ENOMEM; } } else { if (malloc_init()) ret = NULL; else ret = imalloc(size); if (ret == NULL) { if (opt_xmalloc) { _malloc_message(_getprogname(), ": (malloc) Error in realloc(): out of " "memory\n", "", ""); abort(); } errno = ENOMEM; } } RETURN: UTRACE(ptr, size, ret); return (ret); } void free(void *ptr) { UTRACE(ptr, 0, 0); if (ptr != NULL) { assert(malloc_initialized); idalloc(ptr); } } /* * End malloc(3)-compatible functions. */ /******************************************************************************/ /* * Begin non-standard functions. */ size_t malloc_usable_size(const void *ptr) { assert(ptr != NULL); return (isalloc(ptr)); } /* * End non-standard functions. */ /******************************************************************************/ /* * Begin library-private functions, used by threading libraries for protection * of malloc during fork(). These functions are only called if the program is * running in threaded mode, so there is no need to check whether the program * is threaded here. */ void _malloc_prefork(void) { unsigned i; /* Acquire all mutexes in a safe order. */ malloc_spin_lock(&arenas_lock); for (i = 0; i < narenas; i++) { if (arenas[i] != NULL) malloc_spin_lock(&arenas[i]->lock); } malloc_spin_unlock(&arenas_lock); malloc_mutex_lock(&base_mtx); malloc_mutex_lock(&chunks_mtx); } void _malloc_postfork(void) { unsigned i; /* Release all mutexes, now that fork() has completed. */ malloc_mutex_unlock(&chunks_mtx); malloc_mutex_unlock(&base_mtx); malloc_spin_lock(&arenas_lock); for (i = 0; i < narenas; i++) { if (arenas[i] != NULL) malloc_spin_unlock(&arenas[i]->lock); } malloc_spin_unlock(&arenas_lock); } /* * End library-private functions. */ /******************************************************************************/