Commit 09884951 authored by Tejun Heo's avatar Tejun Heo

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
...@@ -271,6 +271,19 @@ static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, ...@@ -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); 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) \ #define for_each_gcwq_cpu(cpu) \
for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \
(cpu) < WORK_CPU_NONE; \ (cpu) < WORK_CPU_NONE; \
......
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