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