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