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sched/hotplug: Make activate() the last hotplug step

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The scheduler can handle per cpu threads before the cpu is set to active and
it does not allow user space threads on the cpu before active is
set. Attaching to the scheduling domains is also not required before user
space threads can be handled.

Move the activation to the end of the hotplug state space. That also means
that deactivation is the first action when a cpu is shut down.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.597477199@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2016-03-10 12:54:19 +01:00
parent f2785ddb53
commit aaddd7d1c7
2 changed files with 10 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/cpuhotplug.h
View File

@ -13,11 +13,11 @@ enum cpuhp_state {
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
CPUHP_AP_ONLINE_IDLE,
CPUHP_AP_ACTIVE,
CPUHP_AP_SMPBOOT_THREADS,
CPUHP_AP_NOTIFY_ONLINE,
CPUHP_AP_ONLINE_DYN,
CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30,
CPUHP_AP_ACTIVE,
CPUHP_ONLINE,
};

15
kernel/cpu.c
View File

@ -1242,12 +1242,6 @@ static struct cpuhp_step cpuhp_ap_states[] = {
[CPUHP_AP_ONLINE] = {
.name = "ap:online",
},
/* First state is scheduler control. Interrupts are enabled */
[CPUHP_AP_ACTIVE] = {
.name = "sched:active",
.startup = sched_cpu_activate,
.teardown = sched_cpu_deactivate,
},
/* Handle smpboot threads park/unpark */
[CPUHP_AP_SMPBOOT_THREADS] = {
.name = "smpboot:threads",
@ -1269,6 +1263,15 @@ static struct cpuhp_step cpuhp_ap_states[] = {
* The dynamically registered state space is here
*/
#ifdef CONFIG_SMP
/* Last state is scheduler control setting the cpu active */
[CPUHP_AP_ACTIVE] = {
.name = "sched:active",
.startup = sched_cpu_activate,
.teardown = sched_cpu_deactivate,
},
#endif
/* CPU is fully up and running. */
[CPUHP_ONLINE] = {
.name = "online",