cpu: Handle smpboot_unpark_threads() uniformly

Commit 00df35f99191 (cpu: Defer smpboot kthread unparking until CPU known
to scheduler) put the online path's call to smpboot_unpark_threads()
into a CPU-hotplug notifier.  This commit places the offline-failure
paths call into the same notifier for the sake of uniformity.

Note that it is not currently possible to place the offline path's call to
smpboot_park_threads() into an existing notifier because the CPU_DYING
notifiers run in a restricted environment, and the CPU_UP_PREPARE
notifiers run too soon.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 94bbe46..260eb7d 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -398,7 +398,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
        err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
        if (err) {
                /* CPU didn't die: tell everyone.  Can't complain. */
-               smpboot_unpark_threads(cpu);
                cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
                goto out_release;
        }
@@ -463,6 +462,7 @@ static int smpboot_thread_call(struct notifier_block *nfb,
 
        switch (action & ~CPU_TASKS_FROZEN) {
 
+       case CPU_DOWN_FAILED:
        case CPU_ONLINE:
                smpboot_unpark_threads(cpu);
                break;