2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1987, 1993
5 * The Regents of the University of California.
6 * Copyright (c) 2005, 2009 Robert N. M. Watson
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10 * modification, are permitted provided that the following conditions
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13 * notice, this list of conditions and the following disclaimer.
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34 #ifndef _SYS_MALLOC_H_
35 #define _SYS_MALLOC_H_
38 #include <sys/param.h>
40 #include <sys/systm.h>
42 #include <sys/queue.h>
43 #include <sys/_lock.h>
44 #include <sys/_mutex.h>
45 #include <machine/_limits.h>
47 #define MINALLOCSIZE UMA_SMALLEST_UNIT
50 * Flags to memory allocation functions.
52 #define M_NOWAIT 0x0001 /* do not block */
53 #define M_WAITOK 0x0002 /* ok to block */
54 #define M_NORECLAIM 0x0080 /* do not reclaim after failure */
55 #define M_ZERO 0x0100 /* bzero the allocation */
56 #define M_NOVM 0x0200 /* don't ask VM for pages */
57 #define M_USE_RESERVE 0x0400 /* can alloc out of reserve memory */
58 #define M_NODUMP 0x0800 /* don't dump pages in this allocation */
59 #define M_FIRSTFIT 0x1000 /* only for vmem, fast fit */
60 #define M_BESTFIT 0x2000 /* only for vmem, low fragmentation */
61 #define M_EXEC 0x4000 /* allocate executable space */
62 #define M_NEXTFIT 0x8000 /* only for vmem, follow cursor */
64 #define M_VERSION 2020110501
67 * Two malloc type structures are present: malloc_type, which is used by a
68 * type owner to declare the type, and malloc_type_internal, which holds
69 * malloc-owned statistics and other ABI-sensitive fields, such as the set of
70 * malloc statistics indexed by the compile-time MAXCPU constant.
71 * Applications should avoid introducing dependence on the allocator private
72 * data layout and size.
74 * The malloc_type ks_next field is protected by malloc_mtx. Other fields in
75 * malloc_type are static after initialization so unsynchronized.
77 * Statistics in malloc_type_stats are written only when holding a critical
78 * section and running on the CPU associated with the index into the stat
79 * array, but read lock-free resulting in possible (minor) races, which the
80 * monitoring app should take into account.
82 struct malloc_type_stats {
83 uint64_t mts_memalloced; /* Bytes allocated on CPU. */
84 uint64_t mts_memfreed; /* Bytes freed on CPU. */
85 uint64_t mts_numallocs; /* Number of allocates on CPU. */
86 uint64_t mts_numfrees; /* number of frees on CPU. */
87 uint64_t mts_size; /* Bitmask of sizes allocated on CPU. */
88 uint64_t _mts_reserved1; /* Reserved field. */
89 uint64_t _mts_reserved2; /* Reserved field. */
90 uint64_t _mts_reserved3; /* Reserved field. */
93 _Static_assert(sizeof(struct malloc_type_stats) == 64,
94 "allocations come from pcpu_zone_64");
97 * Index definitions for the mti_probes[] array.
99 #define DTMALLOC_PROBE_MALLOC 0
100 #define DTMALLOC_PROBE_FREE 1
101 #define DTMALLOC_PROBE_MAX 2
103 struct malloc_type_internal {
104 uint32_t mti_probes[DTMALLOC_PROBE_MAX];
105 /* DTrace probe ID array. */
107 struct malloc_type_stats *mti_stats;
112 * Public data structure describing a malloc type.
115 struct malloc_type *ks_next; /* Next in global chain. */
116 u_long ks_version; /* Detect programmer error. */
117 const char *ks_shortdesc; /* Printable type name. */
118 struct malloc_type_internal ks_mti;
122 * Statistics structure headers for user space. The kern.malloc sysctl
123 * exposes a structure stream consisting of a stream header, then a series of
124 * malloc type headers and statistics structures (quantity maxcpus). For
125 * convenience, the kernel will provide the current value of maxcpus at the
126 * head of the stream.
128 #define MALLOC_TYPE_STREAM_VERSION 0x00000001
129 struct malloc_type_stream_header {
130 uint32_t mtsh_version; /* Stream format version. */
131 uint32_t mtsh_maxcpus; /* Value of MAXCPU for stream. */
132 uint32_t mtsh_count; /* Number of records. */
133 uint32_t _mtsh_pad; /* Pad/reserved field. */
136 #define MALLOC_MAX_NAME 32
137 struct malloc_type_header {
138 char mth_name[MALLOC_MAX_NAME];
142 #define MALLOC_DEFINE(type, shortdesc, longdesc) \
143 struct malloc_type type[1] = { \
146 .ks_version = M_VERSION, \
147 .ks_shortdesc = shortdesc, \
150 SYSINIT(type##_init, SI_SUB_KMEM, SI_ORDER_THIRD, malloc_init, \
152 SYSUNINIT(type##_uninit, SI_SUB_KMEM, SI_ORDER_ANY, \
155 #define MALLOC_DECLARE(type) \
156 extern struct malloc_type type[1]
158 MALLOC_DECLARE(M_CACHE);
159 MALLOC_DECLARE(M_DEVBUF);
160 MALLOC_DECLARE(M_TEMP);
163 * XXX this should be declared in <sys/uio.h>, but that tends to fail
164 * because <sys/uio.h> is included in a header before the source file
165 * has a chance to include <sys/malloc.h> to get MALLOC_DECLARE() defined.
167 MALLOC_DECLARE(M_IOV);
170 extern struct mtx malloc_mtx;
173 * Function type used when iterating over the list of malloc types.
175 typedef void malloc_type_list_func_t(struct malloc_type *, void *);
177 void contigfree(void *addr, unsigned long size, struct malloc_type *type);
178 void *contigmalloc(unsigned long size, struct malloc_type *type, int flags,
179 vm_paddr_t low, vm_paddr_t high, unsigned long alignment,
180 vm_paddr_t boundary) __malloc_like __result_use_check
181 __alloc_size(1) __alloc_align(6);
182 void *contigmalloc_domainset(unsigned long size, struct malloc_type *type,
183 struct domainset *ds, int flags, vm_paddr_t low, vm_paddr_t high,
184 unsigned long alignment, vm_paddr_t boundary)
185 __malloc_like __result_use_check __alloc_size(1) __alloc_align(7);
186 void free(void *addr, struct malloc_type *type);
187 void zfree(void *addr, struct malloc_type *type);
188 void *malloc(size_t size, struct malloc_type *type, int flags) __malloc_like
189 __result_use_check __alloc_size(1);
191 * Try to optimize malloc(..., ..., M_ZERO) allocations by doing zeroing in
192 * place if the size is known at compilation time.
194 * Passing the flag down requires malloc to blindly zero the entire object.
195 * In practice a lot of the zeroing can be avoided if most of the object
196 * gets explicitly initialized after the allocation. Letting the compiler
197 * zero in place gives it the opportunity to take advantage of this state.
199 * Note that the operation is only applicable if both flags and size are
200 * known at compilation time. If M_ZERO is passed but M_WAITOK is not, the
201 * allocation can fail and a NULL check is needed. However, if M_WAITOK is
202 * passed we know the allocation must succeed and the check can be elided.
204 * _malloc_item = malloc(_size, type, (flags) &~ M_ZERO);
205 * if (((flags) & M_WAITOK) != 0 || _malloc_item != NULL)
206 * bzero(_malloc_item, _size);
208 * If the flag is set, the compiler knows the left side is always true,
209 * therefore the entire statement is true and the callsite is:
211 * _malloc_item = malloc(_size, type, (flags) &~ M_ZERO);
212 * bzero(_malloc_item, _size);
214 * If the flag is not set, the compiler knows the left size is always false
215 * and the NULL check is needed, therefore the callsite is:
217 * _malloc_item = malloc(_size, type, (flags) &~ M_ZERO);
218 * if (_malloc_item != NULL)
219 * bzero(_malloc_item, _size);
221 * The implementation is a macro because of what appears to be a clang 6 bug:
222 * an inline function variant ended up being compiled to a mere malloc call
223 * regardless of argument. gcc generates expected code (like the above).
225 #define malloc(size, type, flags) ({ \
226 void *_malloc_item; \
227 size_t _size = (size); \
228 if (__builtin_constant_p(size) && __builtin_constant_p(flags) &&\
229 ((flags) & M_ZERO) != 0) { \
230 _malloc_item = malloc(_size, type, (flags) &~ M_ZERO); \
231 if (((flags) & M_WAITOK) != 0 || \
232 __predict_true(_malloc_item != NULL)) \
233 memset(_malloc_item, 0, _size); \
235 _malloc_item = malloc(_size, type, flags); \
240 void *malloc_domainset(size_t size, struct malloc_type *type,
241 struct domainset *ds, int flags) __malloc_like __result_use_check
243 void *mallocarray(size_t nmemb, size_t size, struct malloc_type *type,
244 int flags) __malloc_like __result_use_check
246 void *mallocarray_domainset(size_t nmemb, size_t size, struct malloc_type *type,
247 struct domainset *ds, int flags) __malloc_like __result_use_check
249 void *malloc_exec(size_t size, struct malloc_type *type, int flags) __malloc_like
250 __result_use_check __alloc_size(1);
251 void *malloc_domainset_exec(size_t size, struct malloc_type *type,
252 struct domainset *ds, int flags) __malloc_like __result_use_check
254 void malloc_init(void *);
255 void malloc_type_allocated(struct malloc_type *type, unsigned long size);
256 void malloc_type_freed(struct malloc_type *type, unsigned long size);
257 void malloc_type_list(malloc_type_list_func_t *, void *);
258 void malloc_uninit(void *);
259 size_t malloc_size(size_t);
260 size_t malloc_usable_size(const void *);
261 void *realloc(void *addr, size_t size, struct malloc_type *type, int flags)
262 __result_use_check __alloc_size(2);
263 void *reallocf(void *addr, size_t size, struct malloc_type *type, int flags)
264 __result_use_check __alloc_size(2);
265 void *malloc_aligned(size_t size, size_t align, struct malloc_type *type,
266 int flags) __malloc_like __result_use_check __alloc_size(1);
267 void *malloc_domainset_aligned(size_t size, size_t align,
268 struct malloc_type *mtp, struct domainset *ds, int flags)
269 __malloc_like __result_use_check __alloc_size(1);
271 struct malloc_type *malloc_desc2type(const char *desc);
274 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
275 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
277 #define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 8 / 2))
279 WOULD_OVERFLOW(size_t nmemb, size_t size)
282 return ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
283 nmemb > 0 && __SIZE_T_MAX / nmemb < size);
285 #undef MUL_NO_OVERFLOW
290 * The native stand malloc / free interface we're mapping to
292 extern void Free(void *p, const char *file, int line);
293 extern void *Malloc(size_t bytes, const char *file, int line);
296 * Minimal standalone malloc implementation / environment. None of the
297 * flags mean anything and there's no need declare malloc types.
298 * Define the simple alloc / free routines in terms of Malloc and
299 * Free. None of the kernel features that this stuff disables are needed.
304 #define MALLOC_DECLARE(x)
306 #define kmem_zalloc(size, flags) ({ \
307 void *p = Malloc((size), __FILE__, __LINE__); \
308 if (p == NULL && (flags & M_WAITOK) != 0) \
309 panic("Could not malloc %zd bytes with M_WAITOK from %s line %d", \
310 (size_t)size, __FILE__, __LINE__); \
314 #define kmem_free(p, size) Free(p, __FILE__, __LINE__)
317 * ZFS mem.h define that's the OpenZFS porting layer way of saying
318 * M_WAITOK. Given the above, it will also be a nop.
320 #define KM_SLEEP M_WAITOK
321 #define KM_NOSLEEP M_NOWAIT
322 #endif /* _STANDALONE */
323 #endif /* !_SYS_MALLOC_H_ */