diff options
| -rw-r--r-- | include/linux/cpumask.h | 44 | ||||
| -rw-r--r-- | lib/cpumask.c | 28 |
2 files changed, 57 insertions, 15 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 9a71af8097ca..e4f9136a4a63 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -337,6 +337,50 @@ unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) return i; } +/** + * cpumask_nth - get the first cpu in a cpumask + * @srcp: the cpumask pointer + * @cpu: the N'th cpu to find, starting from 0 + * + * Returns >= nr_cpu_ids if such cpu doesn't exist. + */ +static inline unsigned int cpumask_nth(unsigned int cpu, const struct cpumask *srcp) +{ + return find_nth_bit(cpumask_bits(srcp), nr_cpumask_bits, cpumask_check(cpu)); +} + +/** + * cpumask_nth_and - get the first cpu in 2 cpumasks + * @srcp1: the cpumask pointer + * @srcp2: the cpumask pointer + * @cpu: the N'th cpu to find, starting from 0 + * + * Returns >= nr_cpu_ids if such cpu doesn't exist. + */ +static inline +unsigned int cpumask_nth_and(unsigned int cpu, const struct cpumask *srcp1, + const struct cpumask *srcp2) +{ + return find_nth_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), + nr_cpumask_bits, cpumask_check(cpu)); +} + +/** + * cpumask_nth_andnot - get the first cpu set in 1st cpumask, and clear in 2nd. + * @srcp1: the cpumask pointer + * @srcp2: the cpumask pointer + * @cpu: the N'th cpu to find, starting from 0 + * + * Returns >= nr_cpu_ids if such cpu doesn't exist. + */ +static inline +unsigned int cpumask_nth_andnot(unsigned int cpu, const struct cpumask *srcp1, + const struct cpumask *srcp2) +{ + return find_nth_andnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), + nr_cpumask_bits, cpumask_check(cpu)); +} + #define CPU_BITS_NONE \ { \ [0 ... BITS_TO_LONGS(NR_CPUS)-1] = 0UL \ diff --git a/lib/cpumask.c b/lib/cpumask.c index f0ae119be8c4..2c4a63b6f03f 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -128,23 +128,21 @@ unsigned int cpumask_local_spread(unsigned int i, int node) i %= num_online_cpus(); if (node == NUMA_NO_NODE) { - for_each_cpu(cpu, cpu_online_mask) - if (i-- == 0) - return cpu; + cpu = cpumask_nth(i, cpu_online_mask); + if (cpu < nr_cpu_ids) + return cpu; } else { /* NUMA first. */ - for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask) - if (i-- == 0) - return cpu; - - for_each_cpu(cpu, cpu_online_mask) { - /* Skip NUMA nodes, done above. */ - if (cpumask_test_cpu(cpu, cpumask_of_node(node))) - continue; - - if (i-- == 0) - return cpu; - } + cpu = cpumask_nth_and(i, cpu_online_mask, cpumask_of_node(node)); + if (cpu < nr_cpu_ids) + return cpu; + + i -= cpumask_weight_and(cpu_online_mask, cpumask_of_node(node)); + + /* Skip NUMA nodes, done above. */ + cpu = cpumask_nth_andnot(i, cpu_online_mask, cpumask_of_node(node)); + if (cpu < nr_cpu_ids) + return cpu; } BUG(); } |