[tip:smp/hotplug] cpu/hotplug: Remove CPU_STARTING and CPU_DYING notifier

From: tip-bot for Thomas Gleixner
Date: Tue Sep 06 2016 - 12:38:28 EST


Commit-ID: ee1e714b94521b0bb27b04dfd1728ec51b19d4f0
Gitweb: http://git.kernel.org/tip/ee1e714b94521b0bb27b04dfd1728ec51b19d4f0
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 18 Aug 2016 14:57:16 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 6 Sep 2016 18:30:19 +0200

cpu/hotplug: Remove CPU_STARTING and CPU_DYING notifier

All users are converted to state machine, remove CPU_STARTING and the
corresponding CPU_DYING.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: rt@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20160818125731.27256-2-bigeasy@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
arch/sparc/kernel/smp_32.c | 2 --
include/linux/cpu.h | 12 ------------
include/linux/cpuhotplug.h | 1 -
kernel/cpu.c | 30 ++----------------------------
tools/testing/radix-tree/linux/cpu.h | 13 -------------
5 files changed, 2 insertions(+), 56 deletions(-)

diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index fb30e7c..e80e6ba 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -352,9 +352,7 @@ static void sparc_start_secondary(void *arg)
preempt_disable();
cpu = smp_processor_id();

- /* Invoke the CPU_STARTING notifier callbacks */
notify_cpu_starting(cpu);
-
arch_cpu_pre_online(arg);

/* Set the CPU in the cpu_online_mask */
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 797d9c8..6bf1992 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -61,17 +61,8 @@ struct notifier_block;
#define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */
#define CPU_DOWN_FAILED 0x0006 /* CPU (unsigned)v NOT going down */
#define CPU_DEAD 0x0007 /* CPU (unsigned)v dead */
-#define CPU_DYING 0x0008 /* CPU (unsigned)v not running any task,
- * not handling interrupts, soon dead.
- * Called on the dying cpu, interrupts
- * are already disabled. Must not
- * sleep, must not fail */
#define CPU_POST_DEAD 0x0009 /* CPU (unsigned)v dead, cpu_hotplug
* lock is dropped */
-#define CPU_STARTING 0x000A /* CPU (unsigned)v soon running.
- * Called on the new cpu, just before
- * enabling interrupts. Must not sleep,
- * must not fail */
#define CPU_BROKEN 0x000B /* CPU (unsigned)v did not die properly,
* perhaps due to preemption. */

@@ -86,9 +77,6 @@ struct notifier_block;
#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
#define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
-#define CPU_DYING_FROZEN (CPU_DYING | CPU_TASKS_FROZEN)
-#define CPU_STARTING_FROZEN (CPU_STARTING | CPU_TASKS_FROZEN)
-

#ifdef CONFIG_SMP
extern bool cpuhp_tasks_frozen;
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index b95f7ad..9e6d107 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -69,7 +69,6 @@ enum cpuhp_state {
CPUHP_AP_ARM64_ISNDEP_STARTING,
CPUHP_AP_SMPCFD_DYING,
CPUHP_AP_X86_TBOOT_DYING,
- CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
CPUHP_AP_ONLINE_IDLE,
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 32eef27..d14ae44 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -408,12 +408,6 @@ static int notify_online(unsigned int cpu)
return 0;
}

-static int notify_starting(unsigned int cpu)
-{
- cpu_notify(CPU_STARTING, cpu);
- return 0;
-}
-
static int bringup_wait_for_ap(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
@@ -759,12 +753,6 @@ static int notify_down_prepare(unsigned int cpu)
return err;
}

-static int notify_dying(unsigned int cpu)
-{
- cpu_notify(CPU_DYING, cpu);
- return 0;
-}
-
/* Take this CPU down. */
static int take_cpu_down(void *_param)
{
@@ -823,7 +811,7 @@ static int takedown_cpu(unsigned int cpu)
BUG_ON(cpu_online(cpu));

/*
- * The migration_call() CPU_DYING callback will have removed all
+ * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all
* runnable tasks from the cpu, there's only the idle task left now
* that the migration thread is done doing the stop_machine thing.
*
@@ -876,7 +864,6 @@ void cpuhp_report_idle_dead(void)
#define notify_down_prepare NULL
#define takedown_cpu NULL
#define notify_dead NULL
-#define notify_dying NULL
#endif

#ifdef CONFIG_HOTPLUG_CPU
@@ -966,10 +953,9 @@ EXPORT_SYMBOL(cpu_down);
#endif /*CONFIG_HOTPLUG_CPU*/

/**
- * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
+ * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
* @cpu: cpu that just started
*
- * This function calls the cpu_chain notifiers with CPU_STARTING.
* It must be called by the arch code on the new cpu, before the new cpu
* enables interrupts and before the "boot" cpu returns from __cpu_up().
*/
@@ -1365,18 +1351,6 @@ static struct cpuhp_step cpuhp_ap_states[] = {
.startup.single = NULL,
.teardown.single = rcutree_dying_cpu,
},
- /*
- * Low level startup.single/teardown notifiers. Run with interrupts
- * disabled. Will be removed once the notifiers are converted to
- * states.
- */
- [CPUHP_AP_NOTIFY_STARTING] = {
- .name = "notify:starting",
- .startup.single = notify_starting,
- .teardown.single = notify_dying,
- .skip_onerr = true,
- .cant_stop = true,
- },
/* Entry state on starting. Interrupts enabled from here on. Transient
* state for synchronsization */
[CPUHP_AP_ONLINE] = {
diff --git a/tools/testing/radix-tree/linux/cpu.h b/tools/testing/radix-tree/linux/cpu.h
index 60a4045..7cf4121 100644
--- a/tools/testing/radix-tree/linux/cpu.h
+++ b/tools/testing/radix-tree/linux/cpu.h
@@ -7,19 +7,8 @@
#define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */
#define CPU_DOWN_FAILED 0x0006 /* CPU (unsigned)v NOT going down */
#define CPU_DEAD 0x0007 /* CPU (unsigned)v dead */
-#define CPU_DYING 0x0008 /* CPU (unsigned)v not running any task,
- * not handling interrupts, soon dead.
- * Called on the dying cpu, interrupts
- * are already disabled. Must not
- * sleep, must not fail */
#define CPU_POST_DEAD 0x0009 /* CPU (unsigned)v dead, cpu_hotplug
* lock is dropped */
-#define CPU_STARTING 0x000A /* CPU (unsigned)v soon running.
- * Called on the new cpu, just before
- * enabling interrupts. Must not sleep,
- * must not fail */
-#define CPU_DYING_IDLE 0x000B /* CPU (unsigned)v dying, reached
- * idle loop. */
#define CPU_BROKEN 0x000C /* CPU (unsigned)v did not die properly,
* perhaps due to preemption. */
#define CPU_TASKS_FROZEN 0x0010
@@ -30,5 +19,3 @@
#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
#define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
-#define CPU_DYING_FROZEN (CPU_DYING | CPU_TASKS_FROZEN)
-#define CPU_STARTING_FROZEN (CPU_STARTING | CPU_TASKS_FROZEN)