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 #include <asm/bug.h>
  88
  89 typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
  90 extern cpumask_t _unused_cpumask_arg_;
  91
  92 #define cpu_set(cpu, dst) __cpu_set((cpu), &(dst))
  93 static inline void __cpu_set(int cpu, volatile cpumask_t *dstp)
  94 {
  95         set_bit(cpu, dstp->bits);
  96 }
  97
  98 #define cpu_clear(cpu, dst) __cpu_clear((cpu), &(dst))
  99 static inline void __cpu_clear(int cpu, volatile cpumask_t *dstp)
 100 {
 101         clear_bit(cpu, dstp->bits);
 102 }
 103
 104 #define cpus_setall(dst) __cpus_setall(&(dst), NR_CPUS)
 105 static inline void __cpus_setall(cpumask_t *dstp, int nbits)
 106 {
 107         bitmap_fill(dstp->bits, nbits);
 108 }
 109
 110 #define cpus_clear(dst) __cpus_clear(&(dst), NR_CPUS)
 111 static inline void __cpus_clear(cpumask_t *dstp, int nbits)
 112 {
 113         bitmap_zero(dstp->bits, nbits);
 114 }
 115
 116 /* No static inline type checking - see Subtlety (1) above. */
 117 #define cpu_isset(cpu, cpumask) test_bit((cpu), (cpumask).bits)
 118
 119 #define cpu_test_and_set(cpu, cpumask) __cpu_test_and_set((cpu), &(cpumask))
 120 static inline int __cpu_test_and_set(int cpu, cpumask_t *addr)
 121 {
 122         return test_and_set_bit(cpu, addr->bits);
 123 }
 124
 125 #define cpus_and(dst, src1, src2) __cpus_and(&(dst), &(src1), &(src2), NR_CPUS)
 126 static inline void __cpus_and(cpumask_t *dstp, const cpumask_t *src1p,
 127                                         const cpumask_t *src2p, int nbits)
 128 {
 129         bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
 130 }
 131
 132 #define cpus_or(dst, src1, src2) __cpus_or(&(dst), &(src1), &(src2), NR_CPUS)
 133 static inline void __cpus_or(cpumask_t *dstp, const cpumask_t *src1p,
 134                                         const cpumask_t *src2p, int nbits)
 135 {
 136         bitmap_or(dstp->bits, src1p->bits, src2p->bits, nbits);
 137 }
 138
 139 #define cpus_xor(dst, src1, src2) __cpus_xor(&(dst), &(src1), &(src2), NR_CPUS)
 140 static inline void __cpus_xor(cpumask_t *dstp, const cpumask_t *src1p,
 141                                         const cpumask_t *src2p, int nbits)
 142 {
 143         bitmap_xor(dstp->bits, src1p->bits, src2p->bits, nbits);
 144 }
 145
 146 #define cpus_andnot(dst, src1, src2) \
 147                                 __cpus_andnot(&(dst), &(src1), &(src2), NR_CPUS)
 148 static inline void __cpus_andnot(cpumask_t *dstp, const cpumask_t *src1p,
 149                                         const cpumask_t *src2p, int nbits)
 150 {
 151         bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
 152 }
 153
 154 #define cpus_complement(dst, src) __cpus_complement(&(dst), &(src), NR_CPUS)
 155 static inline void __cpus_complement(cpumask_t *dstp,
 156                                         const cpumask_t *srcp, int nbits)
 157 {
 158         bitmap_complement(dstp->bits, srcp->bits, nbits);
 159 }
 160
 161 #define cpus_equal(src1, src2) __cpus_equal(&(src1), &(src2), NR_CPUS)
 162 static inline int __cpus_equal(const cpumask_t *src1p,
 163                                         const cpumask_t *src2p, int nbits)
 164 {
 165         return bitmap_equal(src1p->bits, src2p->bits, nbits);
 166 }
 167
 168 #define cpus_intersects(src1, src2) __cpus_intersects(&(src1), &(src2), NR_CPUS)
 169 static inline int __cpus_intersects(const cpumask_t *src1p,
 170                                         const cpumask_t *src2p, int nbits)
 171 {
 172         return bitmap_intersects(src1p->bits, src2p->bits, nbits);
 173 }
 174
 175 #define cpus_subset(src1, src2) __cpus_subset(&(src1), &(src2), NR_CPUS)
 176 static inline int __cpus_subset(const cpumask_t *src1p,
 177                                         const cpumask_t *src2p, int nbits)
 178 {
 179         return bitmap_subset(src1p->bits, src2p->bits, nbits);
 180 }
 181
 182 #define cpus_empty(src) __cpus_empty(&(src), NR_CPUS)
 183 static inline int __cpus_empty(const cpumask_t *srcp, int nbits)
 184 {
 185         return bitmap_empty(srcp->bits, nbits);
 186 }
 187
 188 #define cpus_full(cpumask) __cpus_full(&(cpumask), NR_CPUS)
 189 static inline int __cpus_full(const cpumask_t *srcp, int nbits)
 190 {
 191         return bitmap_full(srcp->bits, nbits);
 192 }
 193
 194 #define cpus_weight(cpumask) __cpus_weight(&(cpumask), NR_CPUS)
 195 static inline int __cpus_weight(const cpumask_t *srcp, int nbits)
 196 {
 197         return bitmap_weight(srcp->bits, nbits);
 198 }
 199
 200 #define cpus_shift_right(dst, src, n) \
 201                         __cpus_shift_right(&(dst), &(src), (n), NR_CPUS)
 202 static inline void __cpus_shift_right(cpumask_t *dstp,
 203                                         const cpumask_t *srcp, int n, int nbits)
 204 {
 205         bitmap_shift_right(dstp->bits, srcp->bits, n, nbits);
 206 }
 207
 208 #define cpus_shift_left(dst, src, n) \
 209                         __cpus_shift_left(&(dst), &(src), (n), NR_CPUS)
 210 static inline void __cpus_shift_left(cpumask_t *dstp,
 211                                         const cpumask_t *srcp, int n, int nbits)
 212 {
 213         bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
 214 }
 215
 216 #define first_cpu(src) __first_cpu(&(src), NR_CPUS)
 217 static inline int __first_cpu(const cpumask_t *srcp, int nbits)
 218 {
 219         return min_t(int, nbits, find_first_bit(srcp->bits, nbits));
 220 }
 221
 222 #define next_cpu(n, src) __next_cpu((n), &(src), NR_CPUS)
 223 static inline int __next_cpu(int n, const cpumask_t *srcp, int nbits)
 224 {
 225         return min_t(int, nbits, find_next_bit(srcp->bits, nbits, n+1));
 226 }
 227
 228 #define cpumask_of_cpu(cpu)                                             \
 229 ({                                                                      \
 230         typeof(_unused_cpumask_arg_) m;                                 \
 231         if (sizeof(m) == sizeof(unsigned long)) {                       \
 232                 m.bits[0] = 1UL<<(cpu);                                 \
 233         } else {                                                        \
 234                 cpus_clear(m);                                          \
 235                 cpu_set((cpu), m);                                      \
 236         }                                                               \
 237         m;                                                              \
 238 })
 239
 240 #define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)
 241
 242 #if NR_CPUS <= BITS_PER_LONG
 243
 244 #define CPU_MASK_ALL                                                    \
 245 (cpumask_t) { {                                                         \
 246         [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD                 \
 247 } }
 248
 249 #else
 250
 251 #define CPU_MASK_ALL                                                    \
 252 (cpumask_t) { {                                                         \
 253         [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                        \
 254         [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD                 \
 255 } }
 256
 257 #endif
 258
 259 #define CPU_MASK_NONE                                                   \
 260 (cpumask_t) { {                                                         \
 261         [0 ... BITS_TO_LONGS(NR_CPUS)-1] =  0UL                         \
 262 } }
 263
 264 #define CPU_MASK_CPU0                                                   \
 265 (cpumask_t) { {                                                         \
 266         [0] =  1UL                                                      \
 267 } }
 268
 269 #define cpus_addr(src) ((src).bits)
 270
 271 #define cpumask_scnprintf(buf, len, src) \
 272                         __cpumask_scnprintf((buf), (len), &(src), NR_CPUS)
 273 static inline int __cpumask_scnprintf(char *buf, int len,
 274                                         const cpumask_t *srcp, int nbits)
 275 {
 276         return bitmap_scnprintf(buf, len, srcp->bits, nbits);
 277 }
 278
 279 #define cpumask_parse(ubuf, ulen, dst) \
 280                         __cpumask_parse((ubuf), (ulen), &(dst), NR_CPUS)
 281 static inline int __cpumask_parse(const char __user *buf, int len,
 282                                         cpumask_t *dstp, int nbits)
 283 {
 284         return bitmap_parse(buf, len, dstp->bits, nbits);
 285 }
 286
 287 #define cpulist_scnprintf(buf, len, src) \
 288                         __cpulist_scnprintf((buf), (len), &(src), NR_CPUS)
 289 static inline int __cpulist_scnprintf(char *buf, int len,
 290                                         const cpumask_t *srcp, int nbits)
 291 {
 292         return bitmap_scnlistprintf(buf, len, srcp->bits, nbits);
 293 }
 294
 295 #define cpulist_parse(buf, dst) __cpulist_parse((buf), &(dst), NR_CPUS)
 296 static inline int __cpulist_parse(const char *buf, cpumask_t *dstp, int nbits)
 297 {
 298         return bitmap_parselist(buf, dstp->bits, nbits);
 299 }
 300
 301 #define cpu_remap(oldbit, old, new) \
 302                 __cpu_remap((oldbit), &(old), &(new), NR_CPUS)
 303 static inline int __cpu_remap(int oldbit,
 304                 const cpumask_t *oldp, const cpumask_t *newp, int nbits)
 305 {
 306         return bitmap_bitremap(oldbit, oldp->bits, newp->bits, nbits);
 307 }
 308
 309 #define cpus_remap(dst, src, old, new) \
 310                 __cpus_remap(&(dst), &(src), &(old), &(new), NR_CPUS)
 311 static inline void __cpus_remap(cpumask_t *dstp, const cpumask_t *srcp,
 312                 const cpumask_t *oldp, const cpumask_t *newp, int nbits)
 313 {
 314         bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits);
 315 }
 316
 317 #if NR_CPUS > 1
 318 #define for_each_cpu_mask(cpu, mask)            \
 319         for ((cpu) = first_cpu(mask);           \
 320                 (cpu) < NR_CPUS;                \
 321                 (cpu) = next_cpu((cpu), (mask)))
 322 #else /* NR_CPUS == 1 */
 323 #define for_each_cpu_mask(cpu, mask) for ((cpu) = 0; (cpu) < 1; (cpu)++)
 324 #endif /* NR_CPUS */
 325
 326 /*
 327  * The following particular system cpumasks and operations manage
 328  * possible, present and online cpus.  Each of them is a fixed size
 329  * bitmap of size NR_CPUS.
 330  *
 331  *  #ifdef CONFIG_HOTPLUG_CPU
 332  *     cpu_possible_map - all NR_CPUS bits set
 333  *     cpu_present_map  - has bit 'cpu' set iff cpu is populated
 334  *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler
 335  *  #else
 336  *     cpu_possible_map - has bit 'cpu' set iff cpu is populated
 337  *     cpu_present_map  - copy of cpu_possible_map
 338  *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler
 339  *  #endif
 340  *
 341  *  In either case, NR_CPUS is fixed at compile time, as the static
 342  *  size of these bitmaps.  The cpu_possible_map is fixed at boot
 343  *  time, as the set of CPU id's that it is possible might ever
 344  *  be plugged in at anytime during the life of that system boot.
 345  *  The cpu_present_map is dynamic(*), representing which CPUs
 346  *  are currently plugged in.  And cpu_online_map is the dynamic
 347  *  subset of cpu_present_map, indicating those CPUs available
 348  *  for scheduling.
 349  *
 350  *  If HOTPLUG is enabled, then cpu_possible_map is forced to have
 351  *  all NR_CPUS bits set, otherwise it is just the set of CPUs that
 352  *  ACPI reports present at boot.
 353  *
 354  *  If HOTPLUG is enabled, then cpu_present_map varies dynamically,
 355  *  depending on what ACPI reports as currently plugged in, otherwise
 356  *  cpu_present_map is just a copy of cpu_possible_map.
 357  *
 358  *  (*) Well, cpu_present_map is dynamic in the hotplug case.  If not
 359  *      hotplug, it's a copy of cpu_possible_map, hence fixed at boot.
 360  *
 361  * Subtleties:
 362  * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
 363  *    assumption that their single CPU is online.  The UP
 364  *    cpu_{online,possible,present}_maps are placebos.  Changing them
 365  *    will have no useful affect on the following num_*_cpus()
 366  *    and cpu_*() macros in the UP case.  This ugliness is a UP
 367  *    optimization - don't waste any instructions or memory references
 368  *    asking if you're online or how many CPUs there are if there is
 369  *    only one CPU.
 370  * 2) Most SMP arch's #define some of these maps to be some
 371  *    other map specific to that arch.  Therefore, the following
 372  *    must be #define macros, not inlines.  To see why, examine
 373  *    the assembly code produced by the following.  Note that
 374  *    set1() writes phys_x_map, but set2() writes x_map:
 375  *        int x_map, phys_x_map;
 376  *        #define set1(a) x_map = a
 377  *        inline void set2(int a) { x_map = a; }
 378  *        #define x_map phys_x_map
 379  *        main(){ set1(3); set2(5); }
 380  */
 381
 382 extern cpumask_t cpu_possible_map;
 383 extern cpumask_t cpu_online_map;
 384 extern cpumask_t cpu_present_map;
 385
 386 #if NR_CPUS > 1
 387 #define num_online_cpus()       cpus_weight(cpu_online_map)
 388 #define num_possible_cpus()     cpus_weight(cpu_possible_map)
 389 #define num_present_cpus()      cpus_weight(cpu_present_map)
 390 #define cpu_online(cpu)         cpu_isset((cpu), cpu_online_map)
 391 #define cpu_possible(cpu)       cpu_isset((cpu), cpu_possible_map)
 392 #define cpu_present(cpu)        cpu_isset((cpu), cpu_present_map)
 393 #else
 394 #define num_online_cpus()       1
 395 #define num_possible_cpus()     1
 396 #define num_present_cpus()      1
 397 #define cpu_online(cpu)         ((cpu) == 0)
 398 #define cpu_possible(cpu)       ((cpu) == 0)
 399 #define cpu_present(cpu)        ((cpu) == 0)
 400 #endif
 401
 402 #define any_online_cpu(mask)                    \
 403 ({                                              \
 404         int cpu;                                \
 405         for_each_cpu_mask(cpu, (mask))          \
 406                 if (cpu_online(cpu))            \
 407                         break;                  \
 408         cpu;                                    \
 409 })
 410
 411 #define for_each_cpu(cpu)         for_each_cpu_mask((cpu), cpu_possible_map)
 412 #define for_each_online_cpu(cpu)  for_each_cpu_mask((cpu), cpu_online_map)
 413 #define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map)
 414
 415 /* Find the highest possible smp_processor_id() */
 416 #define highest_possible_processor_id() \
 417 ({ \
 418         unsigned int cpu, highest = 0; \
 419         for_each_cpu_mask(cpu, cpu_possible_map) \
 420                 highest = cpu; \
 421         highest; \
 422 })
 423
 424
 425 #endif /* __LINUX_CPUMASK_H */