![Andrew Morton](/assets/img/avatar_default.png)
Initialising cpu_possible_map to all-ones with CONFIG_HOTPLUG_CPU means that a) All for_each_cpu() loops will iterate across all NR_CPUS CPUs, rather than over possible ones. That can be quite expensive. b) Soon we'll be allocating per-cpu areas only for possible CPUs. So with CPU_MASK_ALL, we'll be wasting memory. I also switched voyager over to not use CPU_MASK_ALL in the non-CPU-hotplug case. Should be OK.. I note that parisc is also using CPU_MASK_ALL. Suggest that it stop doing that. Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Paul Jackson <pj@sgi.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Zwane Mwaikambo <zwane@linuxpower.ca> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
425 lines
14 KiB
C
425 lines
14 KiB
C
#ifndef __LINUX_CPUMASK_H
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#define __LINUX_CPUMASK_H
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/*
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* Cpumasks provide a bitmap suitable for representing the
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* set of CPU's in a system, one bit position per CPU number.
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*
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* See detailed comments in the file linux/bitmap.h describing the
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* data type on which these cpumasks are based.
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*
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* For details of cpumask_scnprintf() and cpumask_parse(),
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* see bitmap_scnprintf() and bitmap_parse() in lib/bitmap.c.
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* For details of cpulist_scnprintf() and cpulist_parse(), see
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* bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c.
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* For details of cpu_remap(), see bitmap_bitremap in lib/bitmap.c
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* For details of cpus_remap(), see bitmap_remap in lib/bitmap.c.
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*
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* The available cpumask operations are:
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*
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* void cpu_set(cpu, mask) turn on bit 'cpu' in mask
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* void cpu_clear(cpu, mask) turn off bit 'cpu' in mask
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* void cpus_setall(mask) set all bits
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* void cpus_clear(mask) clear all bits
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* int cpu_isset(cpu, mask) true iff bit 'cpu' set in mask
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* int cpu_test_and_set(cpu, mask) test and set bit 'cpu' in mask
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*
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* void cpus_and(dst, src1, src2) dst = src1 & src2 [intersection]
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* void cpus_or(dst, src1, src2) dst = src1 | src2 [union]
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* void cpus_xor(dst, src1, src2) dst = src1 ^ src2
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* void cpus_andnot(dst, src1, src2) dst = src1 & ~src2
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* void cpus_complement(dst, src) dst = ~src
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*
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* int cpus_equal(mask1, mask2) Does mask1 == mask2?
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* int cpus_intersects(mask1, mask2) Do mask1 and mask2 intersect?
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* int cpus_subset(mask1, mask2) Is mask1 a subset of mask2?
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* int cpus_empty(mask) Is mask empty (no bits sets)?
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* int cpus_full(mask) Is mask full (all bits sets)?
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* int cpus_weight(mask) Hamming weigh - number of set bits
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*
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* void cpus_shift_right(dst, src, n) Shift right
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* void cpus_shift_left(dst, src, n) Shift left
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*
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* int first_cpu(mask) Number lowest set bit, or NR_CPUS
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* int next_cpu(cpu, mask) Next cpu past 'cpu', or NR_CPUS
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*
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* cpumask_t cpumask_of_cpu(cpu) Return cpumask with bit 'cpu' set
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* CPU_MASK_ALL Initializer - all bits set
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* CPU_MASK_NONE Initializer - no bits set
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* unsigned long *cpus_addr(mask) Array of unsigned long's in mask
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*
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* int cpumask_scnprintf(buf, len, mask) Format cpumask for printing
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* int cpumask_parse(ubuf, ulen, mask) Parse ascii string as cpumask
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* int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing
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* int cpulist_parse(buf, map) Parse ascii string as cpulist
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* int cpu_remap(oldbit, old, new) newbit = map(old, new)(oldbit)
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* int cpus_remap(dst, src, old, new) *dst = map(old, new)(src)
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*
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* for_each_cpu_mask(cpu, mask) for-loop cpu over mask
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*
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* int num_online_cpus() Number of online CPUs
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* int num_possible_cpus() Number of all possible CPUs
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* int num_present_cpus() Number of present CPUs
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*
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* int cpu_online(cpu) Is some cpu online?
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* int cpu_possible(cpu) Is some cpu possible?
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* int cpu_present(cpu) Is some cpu present (can schedule)?
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*
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* int any_online_cpu(mask) First online cpu in mask
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*
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* for_each_cpu(cpu) for-loop cpu over cpu_possible_map
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* for_each_online_cpu(cpu) for-loop cpu over cpu_online_map
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* for_each_present_cpu(cpu) for-loop cpu over cpu_present_map
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*
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* Subtlety:
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* 1) The 'type-checked' form of cpu_isset() causes gcc (3.3.2, anyway)
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* to generate slightly worse code. Note for example the additional
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* 40 lines of assembly code compiling the "for each possible cpu"
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* loops buried in the disk_stat_read() macros calls when compiling
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* drivers/block/genhd.c (arch i386, CONFIG_SMP=y). So use a simple
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* one-line #define for cpu_isset(), instead of wrapping an inline
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* inside a macro, the way we do the other calls.
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*/
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#include <linux/kernel.h>
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#include <linux/threads.h>
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#include <linux/bitmap.h>
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typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
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extern cpumask_t _unused_cpumask_arg_;
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#define cpu_set(cpu, dst) __cpu_set((cpu), &(dst))
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static inline void __cpu_set(int cpu, volatile cpumask_t *dstp)
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{
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set_bit(cpu, dstp->bits);
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}
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#define cpu_clear(cpu, dst) __cpu_clear((cpu), &(dst))
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static inline void __cpu_clear(int cpu, volatile cpumask_t *dstp)
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{
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clear_bit(cpu, dstp->bits);
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}
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#define cpus_setall(dst) __cpus_setall(&(dst), NR_CPUS)
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static inline void __cpus_setall(cpumask_t *dstp, int nbits)
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{
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bitmap_fill(dstp->bits, nbits);
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}
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#define cpus_clear(dst) __cpus_clear(&(dst), NR_CPUS)
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static inline void __cpus_clear(cpumask_t *dstp, int nbits)
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{
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bitmap_zero(dstp->bits, nbits);
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}
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/* No static inline type checking - see Subtlety (1) above. */
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#define cpu_isset(cpu, cpumask) test_bit((cpu), (cpumask).bits)
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#define cpu_test_and_set(cpu, cpumask) __cpu_test_and_set((cpu), &(cpumask))
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static inline int __cpu_test_and_set(int cpu, cpumask_t *addr)
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{
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return test_and_set_bit(cpu, addr->bits);
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}
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#define cpus_and(dst, src1, src2) __cpus_and(&(dst), &(src1), &(src2), NR_CPUS)
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static inline void __cpus_and(cpumask_t *dstp, const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
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}
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#define cpus_or(dst, src1, src2) __cpus_or(&(dst), &(src1), &(src2), NR_CPUS)
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static inline void __cpus_or(cpumask_t *dstp, const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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bitmap_or(dstp->bits, src1p->bits, src2p->bits, nbits);
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}
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#define cpus_xor(dst, src1, src2) __cpus_xor(&(dst), &(src1), &(src2), NR_CPUS)
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static inline void __cpus_xor(cpumask_t *dstp, const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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bitmap_xor(dstp->bits, src1p->bits, src2p->bits, nbits);
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}
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#define cpus_andnot(dst, src1, src2) \
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__cpus_andnot(&(dst), &(src1), &(src2), NR_CPUS)
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static inline void __cpus_andnot(cpumask_t *dstp, const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
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}
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#define cpus_complement(dst, src) __cpus_complement(&(dst), &(src), NR_CPUS)
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static inline void __cpus_complement(cpumask_t *dstp,
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const cpumask_t *srcp, int nbits)
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{
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bitmap_complement(dstp->bits, srcp->bits, nbits);
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}
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#define cpus_equal(src1, src2) __cpus_equal(&(src1), &(src2), NR_CPUS)
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static inline int __cpus_equal(const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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return bitmap_equal(src1p->bits, src2p->bits, nbits);
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}
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#define cpus_intersects(src1, src2) __cpus_intersects(&(src1), &(src2), NR_CPUS)
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static inline int __cpus_intersects(const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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return bitmap_intersects(src1p->bits, src2p->bits, nbits);
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}
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#define cpus_subset(src1, src2) __cpus_subset(&(src1), &(src2), NR_CPUS)
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static inline int __cpus_subset(const cpumask_t *src1p,
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const cpumask_t *src2p, int nbits)
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{
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return bitmap_subset(src1p->bits, src2p->bits, nbits);
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}
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#define cpus_empty(src) __cpus_empty(&(src), NR_CPUS)
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static inline int __cpus_empty(const cpumask_t *srcp, int nbits)
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{
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return bitmap_empty(srcp->bits, nbits);
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}
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#define cpus_full(cpumask) __cpus_full(&(cpumask), NR_CPUS)
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static inline int __cpus_full(const cpumask_t *srcp, int nbits)
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{
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return bitmap_full(srcp->bits, nbits);
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}
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#define cpus_weight(cpumask) __cpus_weight(&(cpumask), NR_CPUS)
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static inline int __cpus_weight(const cpumask_t *srcp, int nbits)
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{
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return bitmap_weight(srcp->bits, nbits);
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}
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#define cpus_shift_right(dst, src, n) \
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__cpus_shift_right(&(dst), &(src), (n), NR_CPUS)
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static inline void __cpus_shift_right(cpumask_t *dstp,
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const cpumask_t *srcp, int n, int nbits)
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{
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bitmap_shift_right(dstp->bits, srcp->bits, n, nbits);
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}
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#define cpus_shift_left(dst, src, n) \
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__cpus_shift_left(&(dst), &(src), (n), NR_CPUS)
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static inline void __cpus_shift_left(cpumask_t *dstp,
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const cpumask_t *srcp, int n, int nbits)
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{
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bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
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}
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#define first_cpu(src) __first_cpu(&(src), NR_CPUS)
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static inline int __first_cpu(const cpumask_t *srcp, int nbits)
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{
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return min_t(int, nbits, find_first_bit(srcp->bits, nbits));
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}
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#define next_cpu(n, src) __next_cpu((n), &(src), NR_CPUS)
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static inline int __next_cpu(int n, const cpumask_t *srcp, int nbits)
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{
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return min_t(int, nbits, find_next_bit(srcp->bits, nbits, n+1));
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}
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#define cpumask_of_cpu(cpu) \
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({ \
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typeof(_unused_cpumask_arg_) m; \
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if (sizeof(m) == sizeof(unsigned long)) { \
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m.bits[0] = 1UL<<(cpu); \
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} else { \
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cpus_clear(m); \
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cpu_set((cpu), m); \
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} \
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m; \
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})
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#define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)
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#if NR_CPUS <= BITS_PER_LONG
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#define CPU_MASK_ALL \
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(cpumask_t) { { \
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[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
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} }
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#else
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#define CPU_MASK_ALL \
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(cpumask_t) { { \
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[0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \
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[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
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} }
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#endif
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#define CPU_MASK_NONE \
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(cpumask_t) { { \
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[0 ... BITS_TO_LONGS(NR_CPUS)-1] = 0UL \
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} }
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#define CPU_MASK_CPU0 \
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(cpumask_t) { { \
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[0] = 1UL \
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} }
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#define cpus_addr(src) ((src).bits)
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#define cpumask_scnprintf(buf, len, src) \
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__cpumask_scnprintf((buf), (len), &(src), NR_CPUS)
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static inline int __cpumask_scnprintf(char *buf, int len,
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const cpumask_t *srcp, int nbits)
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{
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return bitmap_scnprintf(buf, len, srcp->bits, nbits);
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}
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#define cpumask_parse(ubuf, ulen, dst) \
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__cpumask_parse((ubuf), (ulen), &(dst), NR_CPUS)
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static inline int __cpumask_parse(const char __user *buf, int len,
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cpumask_t *dstp, int nbits)
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{
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return bitmap_parse(buf, len, dstp->bits, nbits);
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}
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#define cpulist_scnprintf(buf, len, src) \
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__cpulist_scnprintf((buf), (len), &(src), NR_CPUS)
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static inline int __cpulist_scnprintf(char *buf, int len,
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const cpumask_t *srcp, int nbits)
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{
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return bitmap_scnlistprintf(buf, len, srcp->bits, nbits);
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}
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#define cpulist_parse(buf, dst) __cpulist_parse((buf), &(dst), NR_CPUS)
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static inline int __cpulist_parse(const char *buf, cpumask_t *dstp, int nbits)
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{
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return bitmap_parselist(buf, dstp->bits, nbits);
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}
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#define cpu_remap(oldbit, old, new) \
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__cpu_remap((oldbit), &(old), &(new), NR_CPUS)
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static inline int __cpu_remap(int oldbit,
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const cpumask_t *oldp, const cpumask_t *newp, int nbits)
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{
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return bitmap_bitremap(oldbit, oldp->bits, newp->bits, nbits);
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}
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#define cpus_remap(dst, src, old, new) \
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__cpus_remap(&(dst), &(src), &(old), &(new), NR_CPUS)
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static inline void __cpus_remap(cpumask_t *dstp, const cpumask_t *srcp,
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const cpumask_t *oldp, const cpumask_t *newp, int nbits)
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{
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bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits);
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}
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#if NR_CPUS > 1
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#define for_each_cpu_mask(cpu, mask) \
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for ((cpu) = first_cpu(mask); \
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(cpu) < NR_CPUS; \
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(cpu) = next_cpu((cpu), (mask)))
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#else /* NR_CPUS == 1 */
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#define for_each_cpu_mask(cpu, mask) for ((cpu) = 0; (cpu) < 1; (cpu)++)
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#endif /* NR_CPUS */
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/*
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* The following particular system cpumasks and operations manage
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* possible, present and online cpus. Each of them is a fixed size
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* bitmap of size NR_CPUS.
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*
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* #ifdef CONFIG_HOTPLUG_CPU
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* cpu_possible_map - has bit 'cpu' set iff cpu is populatable
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* cpu_present_map - has bit 'cpu' set iff cpu is populated
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* cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
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* #else
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* cpu_possible_map - has bit 'cpu' set iff cpu is populated
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* cpu_present_map - copy of cpu_possible_map
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* cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
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* #endif
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*
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* In either case, NR_CPUS is fixed at compile time, as the static
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* size of these bitmaps. The cpu_possible_map is fixed at boot
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* time, as the set of CPU id's that it is possible might ever
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* be plugged in at anytime during the life of that system boot.
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* The cpu_present_map is dynamic(*), representing which CPUs
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* are currently plugged in. And cpu_online_map is the dynamic
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* subset of cpu_present_map, indicating those CPUs available
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* for scheduling.
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*
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* If HOTPLUG is enabled, then cpu_possible_map is forced to have
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* all NR_CPUS bits set, otherwise it is just the set of CPUs that
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* ACPI reports present at boot.
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*
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* If HOTPLUG is enabled, then cpu_present_map varies dynamically,
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* depending on what ACPI reports as currently plugged in, otherwise
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* cpu_present_map is just a copy of cpu_possible_map.
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*
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* (*) Well, cpu_present_map is dynamic in the hotplug case. If not
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* hotplug, it's a copy of cpu_possible_map, hence fixed at boot.
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*
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* Subtleties:
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* 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
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* assumption that their single CPU is online. The UP
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* cpu_{online,possible,present}_maps are placebos. Changing them
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* will have no useful affect on the following num_*_cpus()
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* and cpu_*() macros in the UP case. This ugliness is a UP
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* optimization - don't waste any instructions or memory references
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* asking if you're online or how many CPUs there are if there is
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* only one CPU.
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* 2) Most SMP arch's #define some of these maps to be some
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* other map specific to that arch. Therefore, the following
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* must be #define macros, not inlines. To see why, examine
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* the assembly code produced by the following. Note that
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* set1() writes phys_x_map, but set2() writes x_map:
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* int x_map, phys_x_map;
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* #define set1(a) x_map = a
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* inline void set2(int a) { x_map = a; }
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* #define x_map phys_x_map
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* main(){ set1(3); set2(5); }
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*/
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extern cpumask_t cpu_possible_map;
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extern cpumask_t cpu_online_map;
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extern cpumask_t cpu_present_map;
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#if NR_CPUS > 1
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#define num_online_cpus() cpus_weight(cpu_online_map)
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#define num_possible_cpus() cpus_weight(cpu_possible_map)
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#define num_present_cpus() cpus_weight(cpu_present_map)
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#define cpu_online(cpu) cpu_isset((cpu), cpu_online_map)
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#define cpu_possible(cpu) cpu_isset((cpu), cpu_possible_map)
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#define cpu_present(cpu) cpu_isset((cpu), cpu_present_map)
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#else
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#define num_online_cpus() 1
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#define num_possible_cpus() 1
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#define num_present_cpus() 1
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#define cpu_online(cpu) ((cpu) == 0)
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#define cpu_possible(cpu) ((cpu) == 0)
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#define cpu_present(cpu) ((cpu) == 0)
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#endif
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#define any_online_cpu(mask) \
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({ \
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int cpu; \
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for_each_cpu_mask(cpu, (mask)) \
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if (cpu_online(cpu)) \
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break; \
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cpu; \
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})
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#define for_each_cpu(cpu) for_each_cpu_mask((cpu), cpu_possible_map)
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#define for_each_online_cpu(cpu) for_each_cpu_mask((cpu), cpu_online_map)
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#define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map)
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/* Find the highest possible smp_processor_id() */
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#define highest_possible_processor_id() \
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({ \
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unsigned int cpu, highest = 0; \
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for_each_cpu_mask(cpu, cpu_possible_map) \
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highest = cpu; \
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highest; \
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})
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#endif /* __LINUX_CPUMASK_H */
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