Re: [RFC][PATCH 12/13] stop_machine: Remove lglock

From: Oleg Nesterov
Date: Tue Jun 23 2015 - 13:25:42 EST

On 06/23, Oleg Nesterov wrote:
> It would be nice to remove stop_cpus_mutex, it actually protects
> stop_cpus_work... Then probably stop_two_cpus() can just use
> stop_cpus(). We could simply make stop_cpus_mutex per-cpu too,
> but this doesn't look nice.

IOW. Suppose we add ->work_mutex into struct cpu_stopper. Btw,
I think we should move all per-cpu variables there...


for_each_cpu(cpu, cpumask)
mutex_lock(per_cpu(cpu_stopper_task, cpu).work_mutex);

for_each_cpu(cpu, cpumask)

which should be used instead of stop_cpus_mutex. After this change
stop_two_cpus() can just use stop_cpus().

Off-topic. Can't we make __stop_machine() static? The only caller,
_cpu_down() can safely call stop_machine(), get_online_cpus() is
fine under cpu_hotplug_begin().


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at