On Thu, Oct 08, 2015 at 07:01:41PM +0200, Oleg Nesterov wrote:
> @@ -261,12 +276,8 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2,
> cpu_stop_fn_t fn, void *
> set_state(&msdata, MULTI_STOP_PREPARE);
>
> /*
> - * If we observe both CPUs active we know _cpu_down() cannot yet have
> - * queued its stop_machine works and therefore ours will get executed
> - * first. Or its not either one of our CPUs that's getting unplugged,
> - * in which case we don't care.
> - *
> - * This relies on the stopper workqueues to be FIFO.
> + * We do not want to migrate to inactive CPU. FIXME: move this
> + * into migrate_swap_stop() callback.
> */
> if (!cpu_active(cpu1) || !cpu_active(cpu2)) {
> preempt_enable();
I stuck that on top.. I'll have a closer look at the 7 patches later
when I might be more coherent (mad head-ache atm.)
---
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1335,12 +1335,16 @@ static int migrate_swap_stop(void *data)
struct rq *src_rq, *dst_rq;
int ret = -EAGAIN;
+ if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
+ return -EAGAIN;
+
src_rq = cpu_rq(arg->src_cpu);
dst_rq = cpu_rq(arg->dst_cpu);
double_raw_lock(&arg->src_task->pi_lock,
&arg->dst_task->pi_lock);
double_rq_lock(src_rq, dst_rq);
+
if (task_cpu(arg->dst_task) != arg->dst_cpu)
goto unlock;
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -275,15 +275,6 @@ int stop_two_cpus(unsigned int cpu1, uns
cpu_stop_init_done(&done, 2);
set_state(&msdata, MULTI_STOP_PREPARE);
- /*
- * We do not want to migrate to inactive CPU. FIXME: move this
- * into migrate_swap_stop() callback.
- */
- if (!cpu_active(cpu1) || !cpu_active(cpu2)) {
- preempt_enable();
- return -ENOENT;
- }
-
if (cpu1 > cpu2)
swap(cpu1, cpu2);
if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2)) {
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
