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Commit 09884951 authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: explain for_each_*cwq_cpu() iterators 



for_each_*cwq_cpu() are similar to regular CPU iterators except that
it also considers the pseudo CPU number used for unbound workqueues.
Explain them.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
parent 40f2b6ff

kernel/workqueue.c

+13 −0
Original line number Diff line number Diff line
@@ -271,6 +271,19 @@ static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, 
	return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2);

}



/*

 * CPU iterators

 *

 * An extra gcwq is defined for an invalid cpu number

 * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any

 * specific CPU.  The following iterators are similar to

 * for_each_*_cpu() iterators but also considers the unbound gcwq.

 *

 * for_each_gcwq_cpu()		: possible CPUs + WORK_CPU_UNBOUND

 * for_each_online_gcwq_cpu()	: online CPUs + WORK_CPU_UNBOUND

 * for_each_cwq_cpu()		: possible CPUs for bound workqueues,

 *				  WORK_CPU_UNBOUND for unbound workqueues

 */

#define for_each_gcwq_cpu(cpu)						\

	for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3);		\

	     (cpu) < WORK_CPU_NONE;					\