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sched/fair, cpumask: Export for_each_cpu_wrap()

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[ Upstream commit c743f0a5c50f2fcbc628526279cfa24f3dabe182 ]

More users for for_each_cpu_wrap() have appeared. Promote the construct
to generic cpumask interface.

The implementation is slightly modified to reduce arguments.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Lauro Ramos Venancio <lvenanci@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: lwang@redhat.com
Link: http://lkml.kernel.org/r/20170414122005.o35me2h5nowqkxbv@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[dj: include only what's added to the cpumask interface, 4.4 doesn't
     have them in the scheduler]
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Peter Zijlstra 2020-05-21 16:51:42 -04:00 committed by Greg Kroah-Hartman
parent 7653fbfc21
commit 8539c5151a
2 changed files with 49 additions and 0 deletions
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17
include/linux/cpumask.h
View File

@ -232,6 +232,23 @@ unsigned int cpumask_local_spread(unsigned int i, int node);
(cpu) = cpumask_next_zero((cpu), (mask)), \
(cpu) < nr_cpu_ids;)
extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap);
/**
* for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location
* @cpu: the (optionally unsigned) integer iterator
* @mask: the cpumask poiter
* @start: the start location
*
* The implementation does not assume any bit in @mask is set (including @start).
*
* After the loop, cpu is >= nr_cpu_ids.
*/
#define for_each_cpu_wrap(cpu, mask, start) \
for ((cpu) = cpumask_next_wrap((start)-1, (mask), (start), false); \
(cpu) < nr_cpumask_bits; \
(cpu) = cpumask_next_wrap((cpu), (mask), (start), true))
/**
* for_each_cpu_and - iterate over every cpu in both masks
* @cpu: the (optionally unsigned) integer iterator

32
lib/cpumask.c
View File

@ -42,6 +42,38 @@ int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
return i;
}
/**
* cpumask_next_wrap - helper to implement for_each_cpu_wrap
* @n: the cpu prior to the place to search
* @mask: the cpumask pointer
* @start: the start point of the iteration
* @wrap: assume @n crossing @start terminates the iteration
*
* Returns >= nr_cpu_ids on completion
*
* Note: the @wrap argument is required for the start condition when
* we cannot assume @start is set in @mask.
*/
int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
{
int next;
again:
next = cpumask_next(n, mask);
if (wrap && n < start && next >= start) {
return nr_cpumask_bits;
} else if (next >= nr_cpumask_bits) {
wrap = true;
n = -1;
goto again;
}
return next;
}
EXPORT_SYMBOL(cpumask_next_wrap);
/* These are not inline because of header tangles. */
#ifdef CONFIG_CPUMASK_OFFSTACK
/**