diff options
Diffstat (limited to 'include/linux/cpumask.h')
| -rw-r--r-- | include/linux/cpumask.h | 92 |
1 files changed, 62 insertions, 30 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 5df3db5..b49472d 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -17,6 +17,20 @@ * For details of cpus_onto(), see bitmap_onto in lib/bitmap.c. * For details of cpus_fold(), see bitmap_fold in lib/bitmap.c. * + * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + * Note: The alternate operations with the suffix "_nr" are used + * to limit the range of the loop to nr_cpu_ids instead of + * NR_CPUS when NR_CPUS > 64 for performance reasons. + * If NR_CPUS is <= 64 then most assembler bitmask + * operators execute faster with a constant range, so + * the operator will continue to use NR_CPUS. + * + * Another consideration is that nr_cpu_ids is initialized + * to NR_CPUS and isn't lowered until the possible cpus are + * discovered (including any disabled cpus). So early uses + * will span the entire range of NR_CPUS. + * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + * * The available cpumask operations are: * * void cpu_set(cpu, mask) turn on bit 'cpu' in mask @@ -38,12 +52,14 @@ * int cpus_empty(mask) Is mask empty (no bits sets)? * int cpus_full(mask) Is mask full (all bits sets)? * int cpus_weight(mask) Hamming weigh - number of set bits + * int cpus_weight_nr(mask) Same using nr_cpu_ids instead of NR_CPUS * * void cpus_shift_right(dst, src, n) Shift right * void cpus_shift_left(dst, src, n) Shift left * * int first_cpu(mask) Number lowest set bit, or NR_CPUS * int next_cpu(cpu, mask) Next cpu past 'cpu', or NR_CPUS + * int next_cpu_nr(cpu, mask) Next cpu past 'cpu', or nr_cpu_ids * * cpumask_t cpumask_of_cpu(cpu) Return cpumask with bit 'cpu' set * CPU_MASK_ALL Initializer - all bits set @@ -59,7 +75,8 @@ * void cpus_onto(dst, orig, relmap) *dst = orig relative to relmap * void cpus_fold(dst, orig, sz) dst bits = orig bits mod sz * - * for_each_cpu_mask(cpu, mask) for-loop cpu over mask + * for_each_cpu_mask(cpu, mask) for-loop cpu over mask using NR_CPUS + * for_each_cpu_mask_nr(cpu, mask) for-loop cpu over mask using nr_cpu_ids * * int num_online_cpus() Number of online CPUs * int num_possible_cpus() Number of all possible CPUs @@ -216,15 +233,6 @@ static inline void __cpus_shift_left(cpumask_t *dstp, bitmap_shift_left(dstp->bits, srcp->bits, n, nbits); } -#ifdef CONFIG_SMP -int __first_cpu(const cpumask_t *srcp); -#define first_cpu(src) __first_cpu(&(src)) -int __next_cpu(int n, const cpumask_t *srcp); -#define next_cpu(n, src) __next_cpu((n), &(src)) -#else -#define first_cpu(src) ({ (void)(src); 0; }) -#define next_cpu(n, src) ({ (void)(src); 1; }) -#endif #ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP extern cpumask_t *cpumask_of_cpu_map; @@ -343,15 +351,48 @@ static inline void __cpus_fold(cpumask_t *dstp, const cpumask_t *origp, bitmap_fold(dstp->bits, origp->bits, sz, nbits); } -#if NR_CPUS > 1 +#if NR_CPUS == 1 + +#define nr_cpu_ids 1 +#define first_cpu(src) ({ (void)(src); 0; }) +#define next_cpu(n, src) ({ (void)(src); 1; }) +#define any_online_cpu(mask) 0 +#define for_each_cpu_mask(cpu, mask) \ + for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) + +#else /* NR_CPUS > 1 */ + +extern int nr_cpu_ids; +int __first_cpu(const cpumask_t *srcp); +int __next_cpu(int n, const cpumask_t *srcp); +int __any_online_cpu(const cpumask_t *mask); + +#define first_cpu(src) __first_cpu(&(src)) +#define next_cpu(n, src) __next_cpu((n), &(src)) +#define any_online_cpu(mask) __any_online_cpu(&(mask)) #define for_each_cpu_mask(cpu, mask) \ for ((cpu) = first_cpu(mask); \ (cpu) < NR_CPUS; \ (cpu) = next_cpu((cpu), (mask))) -#else /* NR_CPUS == 1 */ -#define for_each_cpu_mask(cpu, mask) \ - for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) -#endif /* NR_CPUS */ +#endif + +#if NR_CPUS <= 64 + +#define next_cpu_nr(n, src) next_cpu(n, src) +#define cpus_weight_nr(cpumask) cpus_weight(cpumask) +#define for_each_cpu_mask_nr(cpu, mask) for_each_cpu_mask(cpu, mask) + +#else /* NR_CPUS > 64 */ + +int __next_cpu_nr(int n, const cpumask_t *srcp); +#define next_cpu_nr(n, src) __next_cpu_nr((n), &(src)) +#define cpus_weight_nr(cpumask) __cpus_weight(&(cpumask), nr_cpu_ids) +#define for_each_cpu_mask_nr(cpu, mask) \ + for ((cpu) = first_cpu(mask); \ + (cpu) < nr_cpu_ids; \ + (cpu) = next_cpu_nr((cpu), (mask))) + +#endif /* NR_CPUS > 64 */ /* * The following particular system cpumasks and operations manage @@ -414,9 +455,9 @@ extern cpumask_t cpu_online_map; extern cpumask_t cpu_present_map; #if NR_CPUS > 1 -#define num_online_cpus() cpus_weight(cpu_online_map) -#define num_possible_cpus() cpus_weight(cpu_possible_map) -#define num_present_cpus() cpus_weight(cpu_present_map) +#define num_online_cpus() cpus_weight_nr(cpu_online_map) +#define num_possible_cpus() cpus_weight_nr(cpu_possible_map) +#define num_present_cpus() cpus_weight_nr(cpu_present_map) #define cpu_online(cpu) cpu_isset((cpu), cpu_online_map) #define cpu_possible(cpu) cpu_isset((cpu), cpu_possible_map) #define cpu_present(cpu) cpu_isset((cpu), cpu_present_map) @@ -431,17 +472,8 @@ extern cpumask_t cpu_present_map; #define cpu_is_offline(cpu) unlikely(!cpu_online(cpu)) -#ifdef CONFIG_SMP -extern int nr_cpu_ids; -#define any_online_cpu(mask) __any_online_cpu(&(mask)) -int __any_online_cpu(const cpumask_t *mask); -#else -#define nr_cpu_ids 1 -#define any_online_cpu(mask) 0 -#endif - -#define for_each_possible_cpu(cpu) for_each_cpu_mask((cpu), cpu_possible_map) -#define for_each_online_cpu(cpu) for_each_cpu_mask((cpu), cpu_online_map) -#define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map) +#define for_each_possible_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_possible_map) +#define for_each_online_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_online_map) +#define for_each_present_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_present_map) #endif /* __LINUX_CPUMASK_H */ |
