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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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 *
Reinette Chatre01a3ee22006-10-11 01:21:55 -070011 * For details of cpumask_scnprintf() and cpumask_parse_user(),
12 * see bitmap_scnprintf() and bitmap_parse_user() in lib/bitmap.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 * For details of cpulist_scnprintf() and cpulist_parse(), see
14 * bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
Paul Jacksonfb5eeee2005-10-30 15:02:33 -080015 * 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.
Paul Jackson7ea931c2008-04-28 02:12:29 -070017 * For details of cpus_onto(), see bitmap_onto in lib/bitmap.c.
18 * For details of cpus_fold(), see bitmap_fold in lib/bitmap.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 *
Mike Travis41df0d612008-05-12 21:21:13 +020020 * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 * Note: The alternate operations with the suffix "_nr" are used
22 * to limit the range of the loop to nr_cpu_ids instead of
23 * NR_CPUS when NR_CPUS > 64 for performance reasons.
24 * If NR_CPUS is <= 64 then most assembler bitmask
25 * operators execute faster with a constant range, so
26 * the operator will continue to use NR_CPUS.
27 *
28 * Another consideration is that nr_cpu_ids is initialized
29 * to NR_CPUS and isn't lowered until the possible cpus are
30 * discovered (including any disabled cpus). So early uses
31 * will span the entire range of NR_CPUS.
32 * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 * The available cpumask operations are:
35 *
36 * void cpu_set(cpu, mask) turn on bit 'cpu' in mask
37 * void cpu_clear(cpu, mask) turn off bit 'cpu' in mask
38 * void cpus_setall(mask) set all bits
39 * void cpus_clear(mask) clear all bits
40 * int cpu_isset(cpu, mask) true iff bit 'cpu' set in mask
41 * int cpu_test_and_set(cpu, mask) test and set bit 'cpu' in mask
42 *
43 * void cpus_and(dst, src1, src2) dst = src1 & src2 [intersection]
44 * void cpus_or(dst, src1, src2) dst = src1 | src2 [union]
45 * void cpus_xor(dst, src1, src2) dst = src1 ^ src2
46 * void cpus_andnot(dst, src1, src2) dst = src1 & ~src2
47 * void cpus_complement(dst, src) dst = ~src
48 *
49 * int cpus_equal(mask1, mask2) Does mask1 == mask2?
50 * int cpus_intersects(mask1, mask2) Do mask1 and mask2 intersect?
51 * int cpus_subset(mask1, mask2) Is mask1 a subset of mask2?
52 * int cpus_empty(mask) Is mask empty (no bits sets)?
53 * int cpus_full(mask) Is mask full (all bits sets)?
54 * int cpus_weight(mask) Hamming weigh - number of set bits
Mike Travis41df0d612008-05-12 21:21:13 +020055 * int cpus_weight_nr(mask) Same using nr_cpu_ids instead of NR_CPUS
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 *
57 * void cpus_shift_right(dst, src, n) Shift right
58 * void cpus_shift_left(dst, src, n) Shift left
59 *
60 * int first_cpu(mask) Number lowest set bit, or NR_CPUS
61 * int next_cpu(cpu, mask) Next cpu past 'cpu', or NR_CPUS
Mike Travis41df0d612008-05-12 21:21:13 +020062 * int next_cpu_nr(cpu, mask) Next cpu past 'cpu', or nr_cpu_ids
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 *
64 * cpumask_t cpumask_of_cpu(cpu) Return cpumask with bit 'cpu' set
Mike Travis65c01182008-07-15 14:14:30 -070065 *ifdef CONFIG_HAS_CPUMASK_OF_CPU
66 * cpumask_of_cpu_ptr_declare(v) Declares cpumask_t *v
67 * cpumask_of_cpu_ptr_next(v, cpu) Sets v = &cpumask_of_cpu_map[cpu]
68 * cpumask_of_cpu_ptr(v, cpu) Combines above two operations
69 *else
70 * cpumask_of_cpu_ptr_declare(v) Declares cpumask_t _v and *v = &_v
71 * cpumask_of_cpu_ptr_next(v, cpu) Sets _v = cpumask_of_cpu(cpu)
72 * cpumask_of_cpu_ptr(v, cpu) Combines above two operations
73 *endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 * CPU_MASK_ALL Initializer - all bits set
75 * CPU_MASK_NONE Initializer - no bits set
76 * unsigned long *cpus_addr(mask) Array of unsigned long's in mask
77 *
Mike Travis77586c22008-07-15 14:14:36 -070078 *if NR_CPUS > BITS_PER_LONG
79 * CPUMASK_ALLOC(m) Declares and allocates struct m *m =
80 * (struct m *)kmalloc(sizeof(*m), ...)
81 * CPUMASK_FREE(m) Macro for kfree(v)
82 *else
83 * CPUMASK_ALLOC(m) Declares struct m _m, *m = &_m
84 * CPUMASK_FREE(m) Nop
85 *endif
86 * CPUMASK_VAR(v, m) Declares cpumask_t *v =
87 * m + offset(struct m, v)
88 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 * int cpumask_scnprintf(buf, len, mask) Format cpumask for printing
Reinette Chatre01a3ee22006-10-11 01:21:55 -070090 * int cpumask_parse_user(ubuf, ulen, mask) Parse ascii string as cpumask
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 * int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing
92 * int cpulist_parse(buf, map) Parse ascii string as cpulist
Paul Jacksonfb5eeee2005-10-30 15:02:33 -080093 * int cpu_remap(oldbit, old, new) newbit = map(old, new)(oldbit)
Paul Jackson7ea931c2008-04-28 02:12:29 -070094 * void cpus_remap(dst, src, old, new) *dst = map(old, new)(src)
95 * void cpus_onto(dst, orig, relmap) *dst = orig relative to relmap
96 * void cpus_fold(dst, orig, sz) dst bits = orig bits mod sz
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 *
Mike Travis41df0d612008-05-12 21:21:13 +020098 * for_each_cpu_mask(cpu, mask) for-loop cpu over mask using NR_CPUS
99 * for_each_cpu_mask_nr(cpu, mask) for-loop cpu over mask using nr_cpu_ids
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 *
101 * int num_online_cpus() Number of online CPUs
102 * int num_possible_cpus() Number of all possible CPUs
103 * int num_present_cpus() Number of present CPUs
104 *
105 * int cpu_online(cpu) Is some cpu online?
106 * int cpu_possible(cpu) Is some cpu possible?
107 * int cpu_present(cpu) Is some cpu present (can schedule)?
108 *
109 * int any_online_cpu(mask) First online cpu in mask
110 *
KAMEZAWA Hiroyuki631d6742006-03-28 01:56:36 -0800111 * for_each_possible_cpu(cpu) for-loop cpu over cpu_possible_map
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 * for_each_online_cpu(cpu) for-loop cpu over cpu_online_map
113 * for_each_present_cpu(cpu) for-loop cpu over cpu_present_map
114 *
115 * Subtlety:
116 * 1) The 'type-checked' form of cpu_isset() causes gcc (3.3.2, anyway)
117 * to generate slightly worse code. Note for example the additional
118 * 40 lines of assembly code compiling the "for each possible cpu"
119 * loops buried in the disk_stat_read() macros calls when compiling
120 * drivers/block/genhd.c (arch i386, CONFIG_SMP=y). So use a simple
121 * one-line #define for cpu_isset(), instead of wrapping an inline
122 * inside a macro, the way we do the other calls.
123 */
124
125#include <linux/kernel.h>
126#include <linux/threads.h>
127#include <linux/bitmap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
130extern cpumask_t _unused_cpumask_arg_;
131
132#define cpu_set(cpu, dst) __cpu_set((cpu), &(dst))
133static inline void __cpu_set(int cpu, volatile cpumask_t *dstp)
134{
135 set_bit(cpu, dstp->bits);
136}
137
138#define cpu_clear(cpu, dst) __cpu_clear((cpu), &(dst))
139static inline void __cpu_clear(int cpu, volatile cpumask_t *dstp)
140{
141 clear_bit(cpu, dstp->bits);
142}
143
144#define cpus_setall(dst) __cpus_setall(&(dst), NR_CPUS)
145static inline void __cpus_setall(cpumask_t *dstp, int nbits)
146{
147 bitmap_fill(dstp->bits, nbits);
148}
149
150#define cpus_clear(dst) __cpus_clear(&(dst), NR_CPUS)
151static inline void __cpus_clear(cpumask_t *dstp, int nbits)
152{
153 bitmap_zero(dstp->bits, nbits);
154}
155
156/* No static inline type checking - see Subtlety (1) above. */
157#define cpu_isset(cpu, cpumask) test_bit((cpu), (cpumask).bits)
158
159#define cpu_test_and_set(cpu, cpumask) __cpu_test_and_set((cpu), &(cpumask))
160static inline int __cpu_test_and_set(int cpu, cpumask_t *addr)
161{
162 return test_and_set_bit(cpu, addr->bits);
163}
164
165#define cpus_and(dst, src1, src2) __cpus_and(&(dst), &(src1), &(src2), NR_CPUS)
166static inline void __cpus_and(cpumask_t *dstp, const cpumask_t *src1p,
167 const cpumask_t *src2p, int nbits)
168{
169 bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
170}
171
172#define cpus_or(dst, src1, src2) __cpus_or(&(dst), &(src1), &(src2), NR_CPUS)
173static inline void __cpus_or(cpumask_t *dstp, const cpumask_t *src1p,
174 const cpumask_t *src2p, int nbits)
175{
176 bitmap_or(dstp->bits, src1p->bits, src2p->bits, nbits);
177}
178
179#define cpus_xor(dst, src1, src2) __cpus_xor(&(dst), &(src1), &(src2), NR_CPUS)
180static inline void __cpus_xor(cpumask_t *dstp, const cpumask_t *src1p,
181 const cpumask_t *src2p, int nbits)
182{
183 bitmap_xor(dstp->bits, src1p->bits, src2p->bits, nbits);
184}
185
186#define cpus_andnot(dst, src1, src2) \
187 __cpus_andnot(&(dst), &(src1), &(src2), NR_CPUS)
188static inline void __cpus_andnot(cpumask_t *dstp, const cpumask_t *src1p,
189 const cpumask_t *src2p, int nbits)
190{
191 bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
192}
193
194#define cpus_complement(dst, src) __cpus_complement(&(dst), &(src), NR_CPUS)
195static inline void __cpus_complement(cpumask_t *dstp,
196 const cpumask_t *srcp, int nbits)
197{
198 bitmap_complement(dstp->bits, srcp->bits, nbits);
199}
200
201#define cpus_equal(src1, src2) __cpus_equal(&(src1), &(src2), NR_CPUS)
202static inline int __cpus_equal(const cpumask_t *src1p,
203 const cpumask_t *src2p, int nbits)
204{
205 return bitmap_equal(src1p->bits, src2p->bits, nbits);
206}
207
208#define cpus_intersects(src1, src2) __cpus_intersects(&(src1), &(src2), NR_CPUS)
209static inline int __cpus_intersects(const cpumask_t *src1p,
210 const cpumask_t *src2p, int nbits)
211{
212 return bitmap_intersects(src1p->bits, src2p->bits, nbits);
213}
214
215#define cpus_subset(src1, src2) __cpus_subset(&(src1), &(src2), NR_CPUS)
216static inline int __cpus_subset(const cpumask_t *src1p,
217 const cpumask_t *src2p, int nbits)
218{
219 return bitmap_subset(src1p->bits, src2p->bits, nbits);
220}
221
222#define cpus_empty(src) __cpus_empty(&(src), NR_CPUS)
223static inline int __cpus_empty(const cpumask_t *srcp, int nbits)
224{
225 return bitmap_empty(srcp->bits, nbits);
226}
227
228#define cpus_full(cpumask) __cpus_full(&(cpumask), NR_CPUS)
229static inline int __cpus_full(const cpumask_t *srcp, int nbits)
230{
231 return bitmap_full(srcp->bits, nbits);
232}
233
234#define cpus_weight(cpumask) __cpus_weight(&(cpumask), NR_CPUS)
235static inline int __cpus_weight(const cpumask_t *srcp, int nbits)
236{
237 return bitmap_weight(srcp->bits, nbits);
238}
239
240#define cpus_shift_right(dst, src, n) \
241 __cpus_shift_right(&(dst), &(src), (n), NR_CPUS)
242static inline void __cpus_shift_right(cpumask_t *dstp,
243 const cpumask_t *srcp, int n, int nbits)
244{
245 bitmap_shift_right(dstp->bits, srcp->bits, n, nbits);
246}
247
248#define cpus_shift_left(dst, src, n) \
249 __cpus_shift_left(&(dst), &(src), (n), NR_CPUS)
250static inline void __cpus_shift_left(cpumask_t *dstp,
251 const cpumask_t *srcp, int n, int nbits)
252{
253 bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
254}
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
Mike Travis9f0e8d02008-04-04 18:11:01 -0700257#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP
258extern cpumask_t *cpumask_of_cpu_map;
Mike Travis65c01182008-07-15 14:14:30 -0700259#define cpumask_of_cpu(cpu) (cpumask_of_cpu_map[cpu])
260#define cpumask_of_cpu_ptr(v, cpu) \
261 const cpumask_t *v = &cpumask_of_cpu(cpu)
262#define cpumask_of_cpu_ptr_declare(v) \
263 const cpumask_t *v
264#define cpumask_of_cpu_ptr_next(v, cpu) \
265 v = &cpumask_of_cpu(cpu)
Mike Travis9f0e8d02008-04-04 18:11:01 -0700266#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267#define cpumask_of_cpu(cpu) \
Mike Travis65c01182008-07-15 14:14:30 -0700268({ \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 typeof(_unused_cpumask_arg_) m; \
270 if (sizeof(m) == sizeof(unsigned long)) { \
271 m.bits[0] = 1UL<<(cpu); \
272 } else { \
273 cpus_clear(m); \
274 cpu_set((cpu), m); \
275 } \
Mike Travis65c01182008-07-15 14:14:30 -0700276 m; \
277})
278#define cpumask_of_cpu_ptr(v, cpu) \
279 cpumask_t _##v = cpumask_of_cpu(cpu); \
280 const cpumask_t *v = &_##v
281#define cpumask_of_cpu_ptr_declare(v) \
282 cpumask_t _##v; \
283 const cpumask_t *v = &_##v
284#define cpumask_of_cpu_ptr_next(v, cpu) \
285 _##v = cpumask_of_cpu(cpu)
Mike Travis9f0e8d02008-04-04 18:11:01 -0700286#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
288#define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)
289
290#if NR_CPUS <= BITS_PER_LONG
291
292#define CPU_MASK_ALL \
293(cpumask_t) { { \
294 [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
295} }
296
Mike Travis321a8e92008-04-04 18:11:02 -0700297#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299#else
300
301#define CPU_MASK_ALL \
302(cpumask_t) { { \
303 [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \
304 [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
305} }
306
Mike Travis321a8e92008-04-04 18:11:02 -0700307/* cpu_mask_all is in init/main.c */
308extern cpumask_t cpu_mask_all;
309#define CPU_MASK_ALL_PTR (&cpu_mask_all)
310
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311#endif
312
313#define CPU_MASK_NONE \
314(cpumask_t) { { \
315 [0 ... BITS_TO_LONGS(NR_CPUS)-1] = 0UL \
316} }
317
318#define CPU_MASK_CPU0 \
319(cpumask_t) { { \
320 [0] = 1UL \
321} }
322
323#define cpus_addr(src) ((src).bits)
324
Mike Travis77586c22008-07-15 14:14:36 -0700325#if NR_CPUS > BITS_PER_LONG
326#define CPUMASK_ALLOC(m) struct m *m = kmalloc(sizeof(*m), GFP_KERNEL)
327#define CPUMASK_FREE(m) kfree(m)
328#else
329#define CPUMASK_ALLOC(m) struct allmasks _m, *m = &_m
330#define CPUMASK_FREE(m)
331#endif
332#define CPUMASK_VAR(v, m) cpumask_t *v = (cpumask_t *) \
333 ((unsigned long)(m) + offsetof(struct m, v))
334
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335#define cpumask_scnprintf(buf, len, src) \
336 __cpumask_scnprintf((buf), (len), &(src), NR_CPUS)
337static inline int __cpumask_scnprintf(char *buf, int len,
338 const cpumask_t *srcp, int nbits)
339{
340 return bitmap_scnprintf(buf, len, srcp->bits, nbits);
341}
342
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700343#define cpumask_parse_user(ubuf, ulen, dst) \
344 __cpumask_parse_user((ubuf), (ulen), &(dst), NR_CPUS)
345static inline int __cpumask_parse_user(const char __user *buf, int len,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 cpumask_t *dstp, int nbits)
347{
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700348 return bitmap_parse_user(buf, len, dstp->bits, nbits);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349}
350
351#define cpulist_scnprintf(buf, len, src) \
352 __cpulist_scnprintf((buf), (len), &(src), NR_CPUS)
353static inline int __cpulist_scnprintf(char *buf, int len,
354 const cpumask_t *srcp, int nbits)
355{
356 return bitmap_scnlistprintf(buf, len, srcp->bits, nbits);
357}
358
359#define cpulist_parse(buf, dst) __cpulist_parse((buf), &(dst), NR_CPUS)
360static inline int __cpulist_parse(const char *buf, cpumask_t *dstp, int nbits)
361{
362 return bitmap_parselist(buf, dstp->bits, nbits);
363}
364
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800365#define cpu_remap(oldbit, old, new) \
366 __cpu_remap((oldbit), &(old), &(new), NR_CPUS)
367static inline int __cpu_remap(int oldbit,
368 const cpumask_t *oldp, const cpumask_t *newp, int nbits)
369{
370 return bitmap_bitremap(oldbit, oldp->bits, newp->bits, nbits);
371}
372
373#define cpus_remap(dst, src, old, new) \
374 __cpus_remap(&(dst), &(src), &(old), &(new), NR_CPUS)
375static inline void __cpus_remap(cpumask_t *dstp, const cpumask_t *srcp,
376 const cpumask_t *oldp, const cpumask_t *newp, int nbits)
377{
378 bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits);
379}
380
Paul Jackson7ea931c2008-04-28 02:12:29 -0700381#define cpus_onto(dst, orig, relmap) \
382 __cpus_onto(&(dst), &(orig), &(relmap), NR_CPUS)
383static inline void __cpus_onto(cpumask_t *dstp, const cpumask_t *origp,
384 const cpumask_t *relmapp, int nbits)
385{
386 bitmap_onto(dstp->bits, origp->bits, relmapp->bits, nbits);
387}
388
389#define cpus_fold(dst, orig, sz) \
390 __cpus_fold(&(dst), &(orig), sz, NR_CPUS)
391static inline void __cpus_fold(cpumask_t *dstp, const cpumask_t *origp,
392 int sz, int nbits)
393{
394 bitmap_fold(dstp->bits, origp->bits, sz, nbits);
395}
396
Mike Travis41df0d612008-05-12 21:21:13 +0200397#if NR_CPUS == 1
398
399#define nr_cpu_ids 1
400#define first_cpu(src) ({ (void)(src); 0; })
401#define next_cpu(n, src) ({ (void)(src); 1; })
402#define any_online_cpu(mask) 0
403#define for_each_cpu_mask(cpu, mask) \
404 for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
405
406#else /* NR_CPUS > 1 */
407
408extern int nr_cpu_ids;
409int __first_cpu(const cpumask_t *srcp);
410int __next_cpu(int n, const cpumask_t *srcp);
411int __any_online_cpu(const cpumask_t *mask);
412
413#define first_cpu(src) __first_cpu(&(src))
414#define next_cpu(n, src) __next_cpu((n), &(src))
415#define any_online_cpu(mask) __any_online_cpu(&(mask))
Alexander van Heukelum7baac8b2008-05-13 11:28:21 +0200416#define for_each_cpu_mask(cpu, mask) \
417 for ((cpu) = -1; \
418 (cpu) = next_cpu((cpu), (mask)), \
419 (cpu) < NR_CPUS; )
Mike Travis41df0d612008-05-12 21:21:13 +0200420#endif
421
422#if NR_CPUS <= 64
423
424#define next_cpu_nr(n, src) next_cpu(n, src)
425#define cpus_weight_nr(cpumask) cpus_weight(cpumask)
426#define for_each_cpu_mask_nr(cpu, mask) for_each_cpu_mask(cpu, mask)
427
428#else /* NR_CPUS > 64 */
429
430int __next_cpu_nr(int n, const cpumask_t *srcp);
431#define next_cpu_nr(n, src) __next_cpu_nr((n), &(src))
432#define cpus_weight_nr(cpumask) __cpus_weight(&(cpumask), nr_cpu_ids)
Alexander van Heukelum7baac8b2008-05-13 11:28:21 +0200433#define for_each_cpu_mask_nr(cpu, mask) \
434 for ((cpu) = -1; \
435 (cpu) = next_cpu_nr((cpu), (mask)), \
436 (cpu) < nr_cpu_ids; )
Mike Travis41df0d612008-05-12 21:21:13 +0200437
438#endif /* NR_CPUS > 64 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
440/*
441 * The following particular system cpumasks and operations manage
442 * possible, present and online cpus. Each of them is a fixed size
443 * bitmap of size NR_CPUS.
444 *
445 * #ifdef CONFIG_HOTPLUG_CPU
Andrew Morton7a8ef1c2006-02-10 01:51:08 -0800446 * cpu_possible_map - has bit 'cpu' set iff cpu is populatable
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 * cpu_present_map - has bit 'cpu' set iff cpu is populated
448 * cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
449 * #else
450 * cpu_possible_map - has bit 'cpu' set iff cpu is populated
451 * cpu_present_map - copy of cpu_possible_map
452 * cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
453 * #endif
454 *
455 * In either case, NR_CPUS is fixed at compile time, as the static
456 * size of these bitmaps. The cpu_possible_map is fixed at boot
457 * time, as the set of CPU id's that it is possible might ever
458 * be plugged in at anytime during the life of that system boot.
459 * The cpu_present_map is dynamic(*), representing which CPUs
460 * are currently plugged in. And cpu_online_map is the dynamic
461 * subset of cpu_present_map, indicating those CPUs available
462 * for scheduling.
463 *
464 * If HOTPLUG is enabled, then cpu_possible_map is forced to have
465 * all NR_CPUS bits set, otherwise it is just the set of CPUs that
466 * ACPI reports present at boot.
467 *
468 * If HOTPLUG is enabled, then cpu_present_map varies dynamically,
469 * depending on what ACPI reports as currently plugged in, otherwise
470 * cpu_present_map is just a copy of cpu_possible_map.
471 *
472 * (*) Well, cpu_present_map is dynamic in the hotplug case. If not
473 * hotplug, it's a copy of cpu_possible_map, hence fixed at boot.
474 *
475 * Subtleties:
476 * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
477 * assumption that their single CPU is online. The UP
478 * cpu_{online,possible,present}_maps are placebos. Changing them
479 * will have no useful affect on the following num_*_cpus()
480 * and cpu_*() macros in the UP case. This ugliness is a UP
481 * optimization - don't waste any instructions or memory references
482 * asking if you're online or how many CPUs there are if there is
483 * only one CPU.
484 * 2) Most SMP arch's #define some of these maps to be some
485 * other map specific to that arch. Therefore, the following
486 * must be #define macros, not inlines. To see why, examine
487 * the assembly code produced by the following. Note that
488 * set1() writes phys_x_map, but set2() writes x_map:
489 * int x_map, phys_x_map;
490 * #define set1(a) x_map = a
491 * inline void set2(int a) { x_map = a; }
492 * #define x_map phys_x_map
493 * main(){ set1(3); set2(5); }
494 */
495
496extern cpumask_t cpu_possible_map;
497extern cpumask_t cpu_online_map;
498extern cpumask_t cpu_present_map;
499
500#if NR_CPUS > 1
Mike Travis41df0d612008-05-12 21:21:13 +0200501#define num_online_cpus() cpus_weight_nr(cpu_online_map)
502#define num_possible_cpus() cpus_weight_nr(cpu_possible_map)
503#define num_present_cpus() cpus_weight_nr(cpu_present_map)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504#define cpu_online(cpu) cpu_isset((cpu), cpu_online_map)
505#define cpu_possible(cpu) cpu_isset((cpu), cpu_possible_map)
506#define cpu_present(cpu) cpu_isset((cpu), cpu_present_map)
507#else
508#define num_online_cpus() 1
509#define num_possible_cpus() 1
510#define num_present_cpus() 1
511#define cpu_online(cpu) ((cpu) == 0)
512#define cpu_possible(cpu) ((cpu) == 0)
513#define cpu_present(cpu) ((cpu) == 0)
514#endif
515
Ingo Molnara2638982007-12-30 11:58:17 +0100516#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
517
Mike Travis41df0d612008-05-12 21:21:13 +0200518#define for_each_possible_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_possible_map)
519#define for_each_online_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_online_map)
520#define for_each_present_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_present_map)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522#endif /* __LINUX_CPUMASK_H */