include/linux/cpumask.h

   1 #ifndef __LINUX_CPUMASK_H
   2 #define __LINUX_CPUMASK_H
   3
   4 /*
   5  * Cpumasks provide a bitmap suitable for representing the
   6  * set of CPU's in a system, one bit position per CPU number.
   7  *
   8  * See detailed comments in the file linux/bitmap.h describing the
   9  * data type on which these cpumasks are based.
  10  *
  11  * For details of cpumask_scnprintf() and cpumask_parse(),
  12  * see bitmap_scnprintf() and bitmap_parse() in lib/bitmap.c.
  13  * For details of cpulist_scnprintf() and cpulist_parse(), see
  14  * bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
  15  * For details of cpu_remap(), see bitmap_bitremap in lib/bitmap.c
  16  * For details of cpus_remap(), see bitmap_remap in lib/bitmap.c.
  17  *
  18  * The available cpumask operations are:
  19  *
  20  * void cpu_set(cpu, mask)              turn on bit 'cpu' in mask
  21  * void cpu_clear(cpu, mask)            turn off bit 'cpu' in mask
  22  * void cpus_setall(mask)               set all bits
  23  * void cpus_clear(mask)                clear all bits
  24  * int cpu_isset(cpu, mask)             true iff bit 'cpu' set in mask
  25  * int cpu_test_and_set(cpu, mask)      test and set bit 'cpu' in mask
  26  *
  27  * void cpus_and(dst, src1, src2)       dst = src1 & src2  [intersection]
  28  * void cpus_or(dst, src1, src2)        dst = src1 | src2  [union]
  29  * void cpus_xor(dst, src1, src2)       dst = src1 ^ src2
  30  * void cpus_andnot(dst, src1, src2)    dst = src1 & ~src2
  31  * void cpus_complement(dst, src)       dst = ~src
  32  *
  33  * int cpus_equal(mask1, mask2)         Does mask1 == mask2?
  34  * int cpus_intersects(mask1, mask2)    Do mask1 and mask2 intersect?
  35  * int cpus_subset(mask1, mask2)        Is mask1 a subset of mask2?
  36  * int cpus_empty(mask)                 Is mask empty (no bits sets)?
  37  * int cpus_full(mask)                  Is mask full (all bits sets)?
  38  * int cpus_weight(mask)                Hamming weigh - number of set bits
  39  *
  40  * void cpus_shift_right(dst, src, n)   Shift right
  41  * void cpus_shift_left(dst, src, n)    Shift left
  42  *
  43  * int first_cpu(mask)                  Number lowest set bit, or NR_CPUS
  44  * int next_cpu(cpu, mask)              Next cpu past 'cpu', or NR_CPUS
  45  *
  46  * cpumask_t cpumask_of_cpu(cpu)        Return cpumask with bit 'cpu' set
  47  * CPU_MASK_ALL                         Initializer - all bits set
  48  * CPU_MASK_NONE                        Initializer - no bits set
  49  * unsigned long *cpus_addr(mask)       Array of unsigned long's in mask
  50  *
  51  * int cpumask_scnprintf(buf, len, mask) Format cpumask for printing
  52  * int cpumask_parse(ubuf, ulen, mask)  Parse ascii string as cpumask
  53  * int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing
  54  * int cpulist_parse(buf, map)          Parse ascii string as cpulist
  55  * int cpu_remap(oldbit, old, new)      newbit = map(old, new)(oldbit)
  56  * int cpus_remap(dst, src, old, new)   *dst = map(old, new)(src)
  57  *
  58  * for_each_cpu_mask(cpu, mask)         for-loop cpu over mask
  59  *
  60  * int num_online_cpus()                Number of online CPUs
  61  * int num_possible_cpus()              Number of all possible CPUs
  62  * int num_present_cpus()               Number of present CPUs
  63  *
  64  * int cpu_online(cpu)                  Is some cpu online?
  65  * int cpu_possible(cpu)                Is some cpu possible?
  66  * int cpu_present(cpu)                 Is some cpu present (can schedule)?
  67  *
  68  * int any_online_cpu(mask)             First online cpu in mask
  69  *
  70  * for_each_cpu(cpu)                    for-loop cpu over cpu_possible_map
  71  * for_each_online_cpu(cpu)             for-loop cpu over cpu_online_map
  72  * for_each_present_cpu(cpu)            for-loop cpu over cpu_present_map
  73  *
  74  * Subtlety:
  75  * 1) The 'type-checked' form of cpu_isset() causes gcc (3.3.2, anyway)
  76  *    to generate slightly worse code.  Note for example the additional
  77  *    40 lines of assembly code compiling the "for each possible cpu"
  78  *    loops buried in the disk_stat_read() macros calls when compiling
  79  *    drivers/block/genhd.c (arch i386, CONFIG_SMP=y).  So use a simple
  80  *    one-line #define for cpu_isset(), instead of wrapping an inline
  81  *    inside a macro, the way we do the other calls.
  82  */
  83
  84 #include <linux/kernel.h>
  85 #include <linux/threads.h>
  86 #include <linux/bitmap.h>
  87
  88 typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
  89 extern cpumask_t _unused_cpumask_arg_;
  90
  91 #define cpu_set(cpu, dst) __cpu_set((cpu), &(dst))
  92 static inline void __cpu_set(int cpu, volatile cpumask_t *dstp)
  93 {
  94         set_bit(cpu, dstp->bits);
  95 }
  96
  97 #define cpu_clear(cpu, dst) __cpu_clear((cpu), &(dst))
  98 static inline void __cpu_clear(int cpu, volatile cpumask_t *dstp)
  99 {
 100         clear_bit(cpu, dstp->bits);
 101 }
 102
 103 #define cpus_setall(dst) __cpus_setall(&(dst), NR_CPUS)
 104 static inline void __cpus_setall(cpumask_t *dstp, int nbits)
 105 {
 106         bitmap_fill(dstp->bits, nbits);
 107 }
 108
 109 #define cpus_clear(dst) __cpus_clear(&(dst), NR_CPUS)
 110 static inline void __cpus_clear(cpumask_t *dstp, int nbits)
 111 {
 112         bitmap_zero(dstp->bits, nbits);
 113 }
 114
 115 /* No static inline type checking - see Subtlety (1) above. */
 116 #define cpu_isset(cpu, cpumask) test_bit((cpu), (cpumask).bits)
 117
 118 #define cpu_test_and_set(cpu, cpumask) __cpu_test_and_set((cpu), &(cpumask))
 119 static inline int __cpu_test_and_set(int cpu, cpumask_t *addr)
 120 {
 121         return test_and_set_bit(cpu, addr->bits);
 122 }
 123
 124 #define cpus_and(dst, src1, src2) __cpus_and(&(dst), &(src1), &(src2), NR_CPUS)
 125 static inline void __cpus_and(cpumask_t *dstp, const cpumask_t *src1p,
 126                                         const cpumask_t *src2p, int nbits)
 127 {
 128         bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
 129 }
 130
 131 #define cpus_or(dst, src1, src2) __cpus_or(&(dst), &(src1), &(src2), NR_CPUS)
 132 static inline void __cpus_or(cpumask_t *dstp, const cpumask_t *src1p,
 133                                         const cpumask_t *src2p, int nbits)
 134 {
 135         bitmap_or(dstp->bits, src1p->bits, src2p->bits, nbits);
 136 }
 137
 138 #define cpus_xor(dst, src1, src2) __cpus_xor(&(dst), &(src1), &(src2), NR_CPUS)
 139 static inline void __cpus_xor(cpumask_t *dstp, const cpumask_t *src1p,
 140                                         const cpumask_t *src2p, int nbits)
 141 {
 142         bitmap_xor(dstp->bits, src1p->bits, src2p->bits, nbits);
 143 }
 144
 145 #define cpus_andnot(dst, src1, src2) \
 146                                 __cpus_andnot(&(dst), &(src1), &(src2), NR_CPUS)
 147 static inline void __cpus_andnot(cpumask_t *dstp, const cpumask_t *src1p,
 148                                         const cpumask_t *src2p, int nbits)
 149 {
 150         bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
 151 }
 152
 153 #define cpus_complement(dst, src) __cpus_complement(&(dst), &(src), NR_CPUS)
 154 static inline void __cpus_complement(cpumask_t *dstp,
 155                                         const cpumask_t *srcp, int nbits)
 156 {
 157         bitmap_complement(dstp->bits, srcp->bits, nbits);
 158 }
 159
 160 #define cpus_equal(src1, src2) __cpus_equal(&(src1), &(src2), NR_CPUS)
 161 static inline int __cpus_equal(const cpumask_t *src1p,
 162                                         const cpumask_t *src2p, int nbits)
 163 {
 164         return bitmap_equal(src1p->bits, src2p->bits, nbits);
 165 }
 166
 167 #define cpus_intersects(src1, src2) __cpus_intersects(&(src1), &(src2), NR_CPUS)
 168 static inline int __cpus_intersects(const cpumask_t *src1p,
 169                                         const cpumask_t *src2p, int nbits)
 170 {
 171         return bitmap_intersects(src1p->bits, src2p->bits, nbits);
 172 }
 173
 174 #define cpus_subset(src1, src2) __cpus_subset(&(src1), &(src2), NR_CPUS)
 175 static inline int __cpus_subset(const cpumask_t *src1p,
 176                                         const cpumask_t *src2p, int nbits)
 177 {
 178         return bitmap_subset(src1p->bits, src2p->bits, nbits);
 179 }
 180
 181 #define cpus_empty(src) __cpus_empty(&(src), NR_CPUS)
 182 static inline int __cpus_empty(const cpumask_t *srcp, int nbits)
 183 {
 184         return bitmap_empty(srcp->bits, nbits);
 185 }
 186
 187 #define cpus_full(cpumask) __cpus_full(&(cpumask), NR_CPUS)
 188 static inline int __cpus_full(const cpumask_t *srcp, int nbits)
 189 {
 190         return bitmap_full(srcp->bits, nbits);
 191 }
 192
 193 #define cpus_weight(cpumask) __cpus_weight(&(cpumask), NR_CPUS)
 194 static inline int __cpus_weight(const cpumask_t *srcp, int nbits)
 195 {
 196         return bitmap_weight(srcp->bits, nbits);
 197 }
 198
 199 #define cpus_shift_right(dst, src, n) \
 200                         __cpus_shift_right(&(dst), &(src), (n), NR_CPUS)
 201 static inline void __cpus_shift_right(cpumask_t *dstp,
 202                                         const cpumask_t *srcp, int n, int nbits)
 203 {
 204         bitmap_shift_right(dstp->bits, srcp->bits, n, nbits);
 205 }
 206
 207 #define cpus_shift_left(dst, src, n) \
 208                         __cpus_shift_left(&(dst), &(src), (n), NR_CPUS)
 209 static inline void __cpus_shift_left(cpumask_t *dstp,
 210                                         const cpumask_t *srcp, int n, int nbits)
 211 {
 212         bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
 213 }
 214
 215 #define first_cpu(src) __first_cpu(&(src), NR_CPUS)
 216 static inline int __first_cpu(const cpumask_t *srcp, int nbits)
 217 {
 218         return min_t(int, nbits, find_first_bit(srcp->bits, nbits));
 219 }
 220
 221 #define next_cpu(n, src) __next_cpu((n), &(src), NR_CPUS)
 222 static inline int __next_cpu(int n, const cpumask_t *srcp, int nbits)
 223 {
 224         return min_t(int, nbits, find_next_bit(srcp->bits, nbits, n+1));
 225 }
 226
 227 #define cpumask_of_cpu(cpu)                                             \
 228 ({                                                                      \
 229         typeof(_unused_cpumask_arg_) m;                                 \
 230         if (sizeof(m) == sizeof(unsigned long)) {                       \
 231                 m.bits[0] = 1UL<<(cpu);                                 \
 232         } else {                                                        \
 233                 cpus_clear(m);                                          \
 234                 cpu_set((cpu), m);                                      \
 235         }                                                               \
 236         m;                                                              \
 237 })
 238
 239 #define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)
 240
 241 #if NR_CPUS <= BITS_PER_LONG
 242
 243 #define CPU_MASK_ALL                                                    \
 244 (cpumask_t) { {                                                         \
 245         [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD                 \
 246 } }
 247
 248 #else
 249
 250 #define CPU_MASK_ALL                                                    \
 251 (cpumask_t) { {                                                         \
 252         [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                        \
 253         [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD                 \
 254 } }
 255
 256 #endif
 257
 258 #define CPU_MASK_NONE                                                   \
 259 (cpumask_t) { {                                                         \
 260         [0 ... BITS_TO_LONGS(NR_CPUS)-1] =  0UL                         \
 261 } }
 262
 263 #define CPU_MASK_CPU0                                                   \
 264 (cpumask_t) { {                                                         \
 265         [0] =  1UL                                                      \
 266 } }
 267
 268 #define cpus_addr(src) ((src).bits)
 269
 270 #define cpumask_scnprintf(buf, len, src) \
 271                         __cpumask_scnprintf((buf), (len), &(src), NR_CPUS)
 272 static inline int __cpumask_scnprintf(char *buf, int len,
 273                                         const cpumask_t *srcp, int nbits)
 274 {
 275         return bitmap_scnprintf(buf, len, srcp->bits, nbits);
 276 }
 277
 278 #define cpumask_parse(ubuf, ulen, dst) \
 279                         __cpumask_parse((ubuf), (ulen), &(dst), NR_CPUS)
 280 static inline int __cpumask_parse(const char __user *buf, int len,
 281                                         cpumask_t *dstp, int nbits)
 282 {
 283         return bitmap_parse(buf, len, dstp->bits, nbits);
 284 }
 285
 286 #define cpulist_scnprintf(buf, len, src) \
 287                         __cpulist_scnprintf((buf), (len), &(src), NR_CPUS)
 288 static inline int __cpulist_scnprintf(char *buf, int len,
 289                                         const cpumask_t *srcp, int nbits)
 290 {
 291         return bitmap_scnlistprintf(buf, len, srcp->bits, nbits);
 292 }
 293
 294 #define cpulist_parse(buf, dst) __cpulist_parse((buf), &(dst), NR_CPUS)
 295 static inline int __cpulist_parse(const char *buf, cpumask_t *dstp, int nbits)
 296 {
 297         return bitmap_parselist(buf, dstp->bits, nbits);
 298 }
 299
 300 #define cpu_remap(oldbit, old, new) \
 301                 __cpu_remap((oldbit), &(old), &(new), NR_CPUS)
 302 static inline int __cpu_remap(int oldbit,
 303                 const cpumask_t *oldp, const cpumask_t *newp, int nbits)
 304 {
 305         return bitmap_bitremap(oldbit, oldp->bits, newp->bits, nbits);
 306 }
 307
 308 #define cpus_remap(dst, src, old, new) \
 309                 __cpus_remap(&(dst), &(src), &(old), &(new), NR_CPUS)
 310 static inline void __cpus_remap(cpumask_t *dstp, const cpumask_t *srcp,
 311                 const cpumask_t *oldp, const cpumask_t *newp, int nbits)
 312 {
 313         bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits);
 314 }
 315
 316 #if NR_CPUS > 1
 317 #define for_each_cpu_mask(cpu, mask)            \
 318         for ((cpu) = first_cpu(mask);           \
 319                 (cpu) < NR_CPUS;                \
 320                 (cpu) = next_cpu((cpu), (mask)))
 321 #else /* NR_CPUS == 1 */
 322 #define for_each_cpu_mask(cpu, mask) for ((cpu) = 0; (cpu) < 1; (cpu)++)
 323 #endif /* NR_CPUS */
 324
 325 /*
 326  * The following particular system cpumasks and operations manage
 327  * possible, present and online cpus.  Each of them is a fixed size
 328  * bitmap of size NR_CPUS.
 329  *
 330  *  #ifdef CONFIG_HOTPLUG_CPU
 331  *     cpu_possible_map - has bit 'cpu' set iff cpu is populatable
 332  *     cpu_present_map  - has bit 'cpu' set iff cpu is populated
 333  *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler
 334  *  #else
 335  *     cpu_possible_map - has bit 'cpu' set iff cpu is populated
 336  *     cpu_present_map  - copy of cpu_possible_map
 337  *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler
 338  *  #endif
 339  *
 340  *  In either case, NR_CPUS is fixed at compile time, as the static
 341  *  size of these bitmaps.  The cpu_possible_map is fixed at boot
 342  *  time, as the set of CPU id's that it is possible might ever
 343  *  be plugged in at anytime during the life of that system boot.
 344  *  The cpu_present_map is dynamic(*), representing which CPUs
 345  *  are currently plugged in.  And cpu_online_map is the dynamic
 346  *  subset of cpu_present_map, indicating those CPUs available
 347  *  for scheduling.
 348  *
 349  *  If HOTPLUG is enabled, then cpu_possible_map is forced to have
 350  *  all NR_CPUS bits set, otherwise it is just the set of CPUs that
 351  *  ACPI reports present at boot.
 352  *
 353  *  If HOTPLUG is enabled, then cpu_present_map varies dynamically,
 354  *  depending on what ACPI reports as currently plugged in, otherwise
 355  *  cpu_present_map is just a copy of cpu_possible_map.
 356  *
 357  *  (*) Well, cpu_present_map is dynamic in the hotplug case.  If not
 358  *      hotplug, it's a copy of cpu_possible_map, hence fixed at boot.
 359  *
 360  * Subtleties:
 361  * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
 362  *    assumption that their single CPU is online.  The UP
 363  *    cpu_{online,possible,present}_maps are placebos.  Changing them
 364  *    will have no useful affect on the following num_*_cpus()
 365  *    and cpu_*() macros in the UP case.  This ugliness is a UP
 366  *    optimization - don't waste any instructions or memory references
 367  *    asking if you're online or how many CPUs there are if there is
 368  *    only one CPU.
 369  * 2) Most SMP arch's #define some of these maps to be some
 370  *    other map specific to that arch.  Therefore, the following
 371  *    must be #define macros, not inlines.  To see why, examine
 372  *    the assembly code produced by the following.  Note that
 373  *    set1() writes phys_x_map, but set2() writes x_map:
 374  *        int x_map, phys_x_map;
 375  *        #define set1(a) x_map = a
 376  *        inline void set2(int a) { x_map = a; }
 377  *        #define x_map phys_x_map
 378  *        main(){ set1(3); set2(5); }
 379  */
 380
 381 extern cpumask_t cpu_possible_map;
 382 extern cpumask_t cpu_online_map;
 383 extern cpumask_t cpu_present_map;
 384
 385 #if NR_CPUS > 1
 386 #define num_online_cpus()       cpus_weight(cpu_online_map)
 387 #define num_possible_cpus()     cpus_weight(cpu_possible_map)
 388 #define num_present_cpus()      cpus_weight(cpu_present_map)
 389 #define cpu_online(cpu)         cpu_isset((cpu), cpu_online_map)
 390 #define cpu_possible(cpu)       cpu_isset((cpu), cpu_possible_map)
 391 #define cpu_present(cpu)        cpu_isset((cpu), cpu_present_map)
 392 #else
 393 #define num_online_cpus()       1
 394 #define num_possible_cpus()     1
 395 #define num_present_cpus()      1
 396 #define cpu_online(cpu)         ((cpu) == 0)
 397 #define cpu_possible(cpu)       ((cpu) == 0)
 398 #define cpu_present(cpu)        ((cpu) == 0)
 399 #endif
 400
 401 #define any_online_cpu(mask)                    \
 402 ({                                              \
 403         int cpu;                                \
 404         for_each_cpu_mask(cpu, (mask))          \
 405                 if (cpu_online(cpu))            \
 406                         break;                  \
 407         cpu;                                    \
 408 })
 409
 410 #define for_each_cpu(cpu)         for_each_cpu_mask((cpu), cpu_possible_map)
 411 #define for_each_online_cpu(cpu)  for_each_cpu_mask((cpu), cpu_online_map)
 412 #define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map)
 413
 414 /* Find the highest possible smp_processor_id() */
 415 #define highest_possible_processor_id() \
 416 ({ \
 417         unsigned int cpu, highest = 0; \
 418         for_each_cpu_mask(cpu, cpu_possible_map) \
 419                 highest = cpu; \
 420         highest; \
 421 })
 422
 423
 424 #endif /* __LINUX_CPUMASK_H */