The following commit has been merged in the linux branch: commit 65a64464349883891e21e74af16c05d6e1eeb4e9 Author: Andi Kleen ak@linux.intel.com Date: Wed Oct 14 06:22:47 2009 +0200
HWPOISON: Allow schedule_on_each_cpu() from keventd
Right now when calling schedule_on_each_cpu() from keventd there is a deadlock because it tries to schedule a work item on the current CPU too. This happens via lru_add_drain_all() in hwpoison.
Just call the function for the current CPU in this case. This is actually faster too.
Debugging with Fengguang Wu & Max Asbock
Signed-off-by: Andi Kleen ak@linux.intel.com
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index addfe2d..f61a2fe 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -667,21 +667,38 @@ EXPORT_SYMBOL(schedule_delayed_work_on); int schedule_on_each_cpu(work_func_t func) { int cpu; + int orig = -1; struct work_struct *works;
works = alloc_percpu(struct work_struct); if (!works) return -ENOMEM;
+ /* + * when running in keventd don't schedule a work item on itself. + * Can just call directly because the work queue is already bound. + * This also is faster. + * Make this a generic parameter for other workqueues? + */ + if (current_is_keventd()) { + orig = raw_smp_processor_id(); + INIT_WORK(per_cpu_ptr(works, orig), func); + func(per_cpu_ptr(works, orig)); + } + get_online_cpus(); for_each_online_cpu(cpu) { struct work_struct *work = per_cpu_ptr(works, cpu);
+ if (cpu == orig) + continue; INIT_WORK(work, func); schedule_work_on(cpu, work); } - for_each_online_cpu(cpu) - flush_work(per_cpu_ptr(works, cpu)); + for_each_online_cpu(cpu) { + if (cpu != orig) + flush_work(per_cpu_ptr(works, cpu)); + } put_online_cpus(); free_percpu(works); return 0;