linux/include/linux/cpumask.h
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   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_user(),
  12 * see bitmap_scnprintf() and bitmap_parse_user() 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_user(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_possible_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
  88typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
  89extern cpumask_t _unused_cpumask_arg_;
  90
  91#define cpu_set(cpu, dst) __cpu_set((cpu), &(dst))
  92static 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))
  98static 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)
 104static 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)
 110static 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))
 119static 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)
 125static 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)
 132static 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)
 139static 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)
 147static 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)
 154static 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)
 161static 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)
 168static 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)
 175static 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)
 182static 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)
 188static 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)
 194static 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)
 201static 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)
 209static 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#ifdef CONFIG_SMP
 216int __first_cpu(const cpumask_t *srcp);
 217#define first_cpu(src) __first_cpu(&(src))
 218int __next_cpu(int n, const cpumask_t *srcp);
 219#define next_cpu(n, src) __next_cpu((n), &(src))
 220#else
 221#define first_cpu(src)          0
 222#define next_cpu(n, src)        1
 223#endif
 224
 225#define cpumask_of_cpu(cpu)                                             \
 226({                                                                      \
 227        typeof(_unused_cpumask_arg_) m;                                 \
 228        if (sizeof(m) == sizeof(unsigned long)) {                       \
 229                m.bits[0] = 1UL<<(cpu);                                 \
 230        } else {                                                        \
 231                cpus_clear(m);                                          \
 232                cpu_set((cpu), m);                                      \
 233        }                                                               \
 234        m;                                                              \
 235})
 236
 237#define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)
 238
 239#if NR_CPUS <= BITS_PER_LONG
 240
 241#define CPU_MASK_ALL                                                    \
 242(cpumask_t) { {                                                         \
 243        [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD                 \
 244} }
 245
 246#else
 247
 248#define CPU_MASK_ALL                                                    \
 249(cpumask_t) { {                                                         \
 250        [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                        \
 251        [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD                 \
 252} }
 253
 254#endif
 255
 256#define CPU_MASK_NONE                                                   \
 257(cpumask_t) { {                                                         \
 258        [0 ... BITS_TO_LONGS(NR_CPUS)-1] =  0UL                         \
 259} }
 260
 261#define CPU_MASK_CPU0                                                   \
 262(cpumask_t) { {                                                         \
 263        [0] =  1UL                                                      \
 264} }
 265
 266#define cpus_addr(src) ((src).bits)
 267
 268#define cpumask_scnprintf(buf, len, src) \
 269                        __cpumask_scnprintf((buf), (len), &(src), NR_CPUS)
 270static inline int __cpumask_scnprintf(char *buf, int len,
 271                                        const cpumask_t *srcp, int nbits)
 272{
 273        return bitmap_scnprintf(buf, len, srcp->bits, nbits);
 274}
 275
 276#define cpumask_parse_user(ubuf, ulen, dst) \
 277                        __cpumask_parse_user((ubuf), (ulen), &(dst), NR_CPUS)
 278static inline int __cpumask_parse_user(const char __user *buf, int len,
 279                                        cpumask_t *dstp, int nbits)
 280{
 281        return bitmap_parse_user(buf, len, dstp->bits, nbits);
 282}
 283
 284#define cpulist_scnprintf(buf, len, src) \
 285                        __cpulist_scnprintf((buf), (len), &(src), NR_CPUS)
 286static inline int __cpulist_scnprintf(char *buf, int len,
 287                                        const cpumask_t *srcp, int nbits)
 288{
 289        return bitmap_scnlistprintf(buf, len, srcp->bits, nbits);
 290}
 291
 292#define cpulist_parse(buf, dst) __cpulist_parse((buf), &(dst), NR_CPUS)
 293static inline int __cpulist_parse(const char *buf, cpumask_t *dstp, int nbits)
 294{
 295        return bitmap_parselist(buf, dstp->bits, nbits);
 296}
 297
 298#define cpu_remap(oldbit, old, new) \
 299                __cpu_remap((oldbit), &(old), &(new), NR_CPUS)
 300static inline int __cpu_remap(int oldbit,
 301                const cpumask_t *oldp, const cpumask_t *newp, int nbits)
 302{
 303        return bitmap_bitremap(oldbit, oldp->bits, newp->bits, nbits);
 304}
 305
 306#define cpus_remap(dst, src, old, new) \
 307                __cpus_remap(&(dst), &(src), &(old), &(new), NR_CPUS)
 308static inline void __cpus_remap(cpumask_t *dstp, const cpumask_t *srcp,
 309                const cpumask_t *oldp, const cpumask_t *newp, int nbits)
 310{
 311        bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits);
 312}
 313
 314#if NR_CPUS > 1
 315#define for_each_cpu_mask(cpu, mask)            \
 316        for ((cpu) = first_cpu(mask);           \
 317                (cpu) < NR_CPUS;                \
 318                (cpu) = next_cpu((cpu), (mask)))
 319#else /* NR_CPUS == 1 */
 320#define for_each_cpu_mask(cpu, mask)            \
 321        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
 322#endif /* NR_CPUS */
 323
 324/*
 325 * The following particular system cpumasks and operations manage
 326 * possible, present and online cpus.  Each of them is a fixed size
 327 * bitmap of size NR_CPUS.
 328 *
 329 *  #ifdef CONFIG_HOTPLUG_CPU
 330 *     cpu_possible_map - has bit 'cpu' set iff cpu is populatable
 331 *     cpu_present_map  - has bit 'cpu' set iff cpu is populated
 332 *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler
 333 *  #else
 334 *     cpu_possible_map - has bit 'cpu' set iff cpu is populated
 335 *     cpu_present_map  - copy of cpu_possible_map
 336 *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler
 337 *  #endif
 338 *
 339 *  In either case, NR_CPUS is fixed at compile time, as the static
 340 *  size of these bitmaps.  The cpu_possible_map is fixed at boot
 341 *  time, as the set of CPU id's that it is possible might ever
 342 *  be plugged in at anytime during the life of that system boot.
 343 *  The cpu_present_map is dynamic(*), representing which CPUs
 344 *  are currently plugged in.  And cpu_online_map is the dynamic
 345 *  subset of cpu_present_map, indicating those CPUs available
 346 *  for scheduling.
 347 *
 348 *  If HOTPLUG is enabled, then cpu_possible_map is forced to have
 349 *  all NR_CPUS bits set, otherwise it is just the set of CPUs that
 350 *  ACPI reports present at boot.
 351 *
 352 *  If HOTPLUG is enabled, then cpu_present_map varies dynamically,
 353 *  depending on what ACPI reports as currently plugged in, otherwise
 354 *  cpu_present_map is just a copy of cpu_possible_map.
 355 *
 356 *  (*) Well, cpu_present_map is dynamic in the hotplug case.  If not
 357 *      hotplug, it's a copy of cpu_possible_map, hence fixed at boot.
 358 *
 359 * Subtleties:
 360 * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
 361 *    assumption that their single CPU is online.  The UP
 362 *    cpu_{online,possible,present}_maps are placebos.  Changing them
 363 *    will have no useful affect on the following num_*_cpus()
 364 *    and cpu_*() macros in the UP case.  This ugliness is a UP
 365 *    optimization - don't waste any instructions or memory references
 366 *    asking if you're online or how many CPUs there are if there is
 367 *    only one CPU.
 368 * 2) Most SMP arch's #define some of these maps to be some
 369 *    other map specific to that arch.  Therefore, the following
 370 *    must be #define macros, not inlines.  To see why, examine
 371 *    the assembly code produced by the following.  Note that
 372 *    set1() writes phys_x_map, but set2() writes x_map:
 373 *        int x_map, phys_x_map;
 374 *        #define set1(a) x_map = a
 375 *        inline void set2(int a) { x_map = a; }
 376 *        #define x_map phys_x_map
 377 *        main(){ set1(3); set2(5); }
 378 */
 379
 380extern cpumask_t cpu_possible_map;
 381extern cpumask_t cpu_online_map;
 382extern cpumask_t cpu_present_map;
 383
 384#if NR_CPUS > 1
 385#define num_online_cpus()       cpus_weight(cpu_online_map)
 386#define num_possible_cpus()     cpus_weight(cpu_possible_map)
 387#define num_present_cpus()      cpus_weight(cpu_present_map)
 388#define cpu_online(cpu)         cpu_isset((cpu), cpu_online_map)
 389#define cpu_possible(cpu)       cpu_isset((cpu), cpu_possible_map)
 390#define cpu_present(cpu)        cpu_isset((cpu), cpu_present_map)
 391#else
 392#define num_online_cpus()       1
 393#define num_possible_cpus()     1
 394#define num_present_cpus()      1
 395#define cpu_online(cpu)         ((cpu) == 0)
 396#define cpu_possible(cpu)       ((cpu) == 0)
 397#define cpu_present(cpu)        ((cpu) == 0)
 398#endif
 399
 400#define cpu_is_offline(cpu)     unlikely(!cpu_online(cpu))
 401
 402#ifdef CONFIG_SMP
 403extern int nr_cpu_ids;
 404#define any_online_cpu(mask) __any_online_cpu(&(mask))
 405int __any_online_cpu(const cpumask_t *mask);
 406#else
 407#define nr_cpu_ids                      1
 408#define any_online_cpu(mask)            0
 409#endif
 410
 411#define for_each_possible_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#endif /* __LINUX_CPUMASK_H */
 416