[PATCH tip/core/rcu 6/9] cpu: Handle smpboot_unpark_threads() uniformly

From: Paul E. McKenney
Date: Tue May 12 2015 - 17:53:03 EST

From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxx>
kernel/cpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 94bbe4695232..260eb7db281e 100644
--- 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) {


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