提交 07f06cb3 编写于 作者: P Peter Zijlstra 提交者: Ingo Molnar

sched: Start stopper early

Ensure the stopper thread is active 'early', because the load balancer
pretty much assumes that its available. And when 'online && active' the
load-balancer is fully available.

Not only the numa balancing stop_two_cpus() caller relies on it, but
also the self migration stuff does, and at CPU_ONLINE time the cpu
really is 'free' to run anything.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: heiko.carstens@de.ibm.com
Link: http://lkml.kernel.org/r/20151009160054.GA10176@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
上级 f0cf16cb
......@@ -475,7 +475,6 @@ static int smpboot_thread_call(struct notifier_block *nfb,
case CPU_DOWN_FAILED:
case CPU_ONLINE:
stop_machine_unpark(cpu);
smpboot_unpark_threads(cpu);
break;
......
......@@ -5545,21 +5545,27 @@ static void set_cpu_rq_start_time(void)
static int sched_cpu_active(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
int cpu = (long)hcpu;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
set_cpu_rq_start_time();
return NOTIFY_OK;
case CPU_ONLINE:
/*
* At this point a starting CPU has marked itself as online via
* set_cpu_online(). But it might not yet have marked itself
* as active, which is essential from here on.
*
* Thus, fall-through and help the starting CPU along.
*/
set_cpu_active(cpu, true);
stop_machine_unpark(cpu);
return NOTIFY_OK;
case CPU_DOWN_FAILED:
set_cpu_active((long)hcpu, true);
set_cpu_active(cpu, true);
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
......
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