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cpumask: add cpumask_nth_{,and,andnot} 

Add cpumask_nth_{,and,andnot} as wrappers around corresponding
find functions, and use it in cpumask_local_spread().

Signed-off-by: Yury Norov <yury.norov@gmail.com>
This commit is contained in:
Yury Norov 2022-09-17 20:07:16 -07:00
parent 97848c10f9
commit 944c417dae
2 changed files with 55 additions and 13 deletions
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44
include/linux/cpumask.h
View File

@ -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 \

24
lib/cpumask.c
View File

@ -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;
cpu = cpumask_nth_and(i, cpu_online_mask, cpumask_of_node(node));
if (cpu < nr_cpu_ids)
return cpu;
for_each_cpu(cpu, cpu_online_mask) {
/* Skip NUMA nodes, done above. */
if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
continue;
i -= cpumask_weight_and(cpu_online_mask, cpumask_of_node(node));
if (i-- == 0)
return cpu;
}
/* 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();
}