diff options
Diffstat (limited to 'include/linux/cpumask.h')
| -rw-r--r-- | include/linux/cpumask.h | 183 |
1 files changed, 133 insertions, 50 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 5df3db5..d3219d7 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 @@ -38,18 +52,52 @@ * 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 + * (can be used as an lvalue) * CPU_MASK_ALL Initializer - all bits set * CPU_MASK_NONE Initializer - no bits set * unsigned long *cpus_addr(mask) Array of unsigned long's in mask * + * CPUMASK_ALLOC kmalloc's a structure that is a composite of many cpumask_t + * variables, and CPUMASK_PTR provides pointers to each field. + * + * The structure should be defined something like this: + * struct my_cpumasks { + * cpumask_t mask1; + * cpumask_t mask2; + * }; + * + * Usage is then: + * CPUMASK_ALLOC(my_cpumasks); + * CPUMASK_PTR(mask1, my_cpumasks); + * CPUMASK_PTR(mask2, my_cpumasks); + * + * --- DO NOT reference cpumask_t pointers until this check --- + * if (my_cpumasks == NULL) + * "kmalloc failed"... + * + * References are now pointers to the cpumask_t variables (*mask1, ...) + * + *if NR_CPUS > BITS_PER_LONG + * CPUMASK_ALLOC(m) Declares and allocates struct m *m = + * kmalloc(sizeof(*m), GFP_KERNEL) + * CPUMASK_FREE(m) Macro for kfree(m) + *else + * CPUMASK_ALLOC(m) Declares struct m _m, *m = &_m + * CPUMASK_FREE(m) Nop + *endif + * CPUMASK_PTR(v, m) Declares cpumask_t *v = &(m->v) + * ------------------------------------------------------------------------ + * * int cpumask_scnprintf(buf, len, mask) Format cpumask for printing * int cpumask_parse_user(ubuf, ulen, mask) Parse ascii string as cpumask * int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing @@ -59,7 +107,8 @@ * 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 @@ -216,33 +265,30 @@ 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 +/* + * Special-case data structure for "single bit set only" constant CPU masks. + * + * We pre-generate all the 64 (or 32) possible bit positions, with enough + * padding to the left and the right, and return the constant pointer + * appropriately offset. + */ +extern const unsigned long + cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)]; -#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP -extern cpumask_t *cpumask_of_cpu_map; -#define cpumask_of_cpu(cpu) (cpumask_of_cpu_map[cpu]) +static inline const cpumask_t *get_cpu_mask(unsigned int cpu) +{ + const unsigned long *p = cpu_bit_bitmap[1 + cpu % BITS_PER_LONG]; + p -= cpu / BITS_PER_LONG; + return (const cpumask_t *)p; +} + +/* + * In cases where we take the address of the cpumask immediately, + * gcc optimizes it out (it's a constant) and there's no huge stack + * variable created: + */ +#define cpumask_of_cpu(cpu) (*get_cpu_mask(cpu)) -#else -#define cpumask_of_cpu(cpu) \ -(*({ \ - typeof(_unused_cpumask_arg_) m; \ - if (sizeof(m) == sizeof(unsigned long)) { \ - m.bits[0] = 1UL<<(cpu); \ - } else { \ - cpus_clear(m); \ - cpu_set((cpu), m); \ - } \ - &m; \ -})) -#endif #define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS) @@ -281,6 +327,15 @@ extern cpumask_t cpu_mask_all; #define cpus_addr(src) ((src).bits) +#if NR_CPUS > BITS_PER_LONG +#define CPUMASK_ALLOC(m) struct m *m = kmalloc(sizeof(*m), GFP_KERNEL) +#define CPUMASK_FREE(m) kfree(m) +#else +#define CPUMASK_ALLOC(m) struct m _m, *m = &_m +#define CPUMASK_FREE(m) +#endif +#define CPUMASK_PTR(v, m) cpumask_t *v = &(m->v) + #define cpumask_scnprintf(buf, len, src) \ __cpumask_scnprintf((buf), (len), &(src), NR_CPUS) static inline int __cpumask_scnprintf(char *buf, int len, @@ -343,25 +398,59 @@ static inline void __cpus_fold(cpumask_t *dstp, const cpumask_t *origp, bitmap_fold(dstp->bits, origp->bits, sz, nbits); } -#if NR_CPUS > 1 -#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) \ +#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) -#endif /* NR_CPUS */ + +#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) = -1; \ + (cpu) = next_cpu((cpu), (mask)), \ + (cpu) < 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) = -1; \ + (cpu) = next_cpu_nr((cpu), (mask)), \ + (cpu) < nr_cpu_ids; ) + +#endif /* NR_CPUS > 64 */ /* * The following particular system cpumasks and operations manage - * possible, present and online cpus. Each of them is a fixed size + * possible, present, active and online cpus. Each of them is a fixed size * bitmap of size NR_CPUS. * * #ifdef CONFIG_HOTPLUG_CPU * cpu_possible_map - has bit 'cpu' set iff cpu is populatable * cpu_present_map - has bit 'cpu' set iff cpu is populated * cpu_online_map - has bit 'cpu' set iff cpu available to scheduler + * cpu_active_map - has bit 'cpu' set iff cpu available to migration * #else * cpu_possible_map - has bit 'cpu' set iff cpu is populated * cpu_present_map - copy of cpu_possible_map @@ -412,14 +501,16 @@ static inline void __cpus_fold(cpumask_t *dstp, const cpumask_t *origp, extern cpumask_t cpu_possible_map; extern cpumask_t cpu_online_map; extern cpumask_t cpu_present_map; +extern cpumask_t cpu_active_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) +#define cpu_active(cpu) cpu_isset((cpu), cpu_active_map) #else #define num_online_cpus() 1 #define num_possible_cpus() 1 @@ -427,21 +518,13 @@ extern cpumask_t cpu_present_map; #define cpu_online(cpu) ((cpu) == 0) #define cpu_possible(cpu) ((cpu) == 0) #define cpu_present(cpu) ((cpu) == 0) +#define cpu_active(cpu) ((cpu) == 0) #endif #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 */ |
