From: Tejun Heo Date: Sun, 1 Aug 2010 09:50:12 +0000 (+0200) Subject: workqueue: explain for_each_*cwq_cpu() iterators X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=098849516dd522a343e659740c8f1394a5b7fa69;p=linux-beck.git 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: Tejun Heo Cc: Andrew Morton --- diff --git a/kernel/workqueue.c b/kernel/workqueue.c index e5cb7faac58e..1105c474073a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -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; \