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Groups > linux.kernel > #1346994
| From | tip-bot for Thomas Gleixner <tipbot@zytor.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [tip:smp/hotplug] cpu/hotplug: Make wait for dead cpu completion based |
| Date | 2016-03-01 21:00 +0100 |
| Message-ID | <r7YCF-5hG-67@gated-at.bofh.it> (permalink) |
| References | <r6vCI-7sv-51@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Commit-ID: e69aab13117efc1987620090e539b4ebeb33a04c
Gitweb: http://git.kernel.org/tip/e69aab13117efc1987620090e539b4ebeb33a04c
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Fri, 26 Feb 2016 18:43:43 +0000
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 1 Mar 2016 20:36:58 +0100
cpu/hotplug: Make wait for dead cpu completion based
Kill the busy spinning on the control side and just wait for the hotplugged
cpu to tell that it reached the dead state.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182341.776157858@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/cpu.h | 5 +++--
include/linux/cpuhotplug.h | 1 +
kernel/cpu.c | 16 ++++++++++++----
kernel/sched/idle.c | 5 +----
4 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 83f3576..91a48d1 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -276,14 +276,15 @@ void arch_cpu_idle_enter(void);
void arch_cpu_idle_exit(void);
void arch_cpu_idle_dead(void);
-DECLARE_PER_CPU(bool, cpu_dead_idle);
-
int cpu_report_state(int cpu);
int cpu_check_up_prepare(int cpu);
void cpu_set_state_online(int cpu);
#ifdef CONFIG_HOTPLUG_CPU
bool cpu_wait_death(unsigned int cpu, int seconds);
bool cpu_report_death(void);
+void cpuhp_report_idle_dead(void);
+#else
+static inline void cpuhp_report_idle_dead(void) { }
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
#endif /* _LINUX_CPU_H_ */
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index ad5d7fc..5d68e15 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -6,6 +6,7 @@ enum cpuhp_state {
CPUHP_CREATE_THREADS,
CPUHP_NOTIFY_PREPARE,
CPUHP_BRINGUP_CPU,
+ CPUHP_AP_IDLE_DEAD,
CPUHP_AP_OFFLINE,
CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
diff --git a/kernel/cpu.c b/kernel/cpu.c
index f1f880f..0e8c07f 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -688,6 +688,7 @@ static int take_cpu_down(void *_param)
static int takedown_cpu(unsigned int cpu)
{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int err;
/*
@@ -733,10 +734,8 @@ static int takedown_cpu(unsigned int cpu)
*
* Wait for the stop thread to go away.
*/
- while (!per_cpu(cpu_dead_idle, cpu))
- cpu_relax();
- smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */
- per_cpu(cpu_dead_idle, cpu) = false;
+ wait_for_completion(&st->done);
+ BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
/* Interrupts are moved away from the dying cpu, reenable alloc/free */
irq_unlock_sparse();
@@ -756,6 +755,15 @@ static int notify_dead(unsigned int cpu)
return 0;
}
+void cpuhp_report_idle_dead(void)
+{
+ struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+
+ BUG_ON(st->state != CPUHP_AP_OFFLINE);
+ st->state = CPUHP_AP_IDLE_DEAD;
+ complete(&st->done);
+}
+
#else
#define notify_down_prepare NULL
#define takedown_cpu NULL
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index a4b9813..8abbe89 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -194,8 +194,6 @@ exit_idle:
rcu_idle_exit();
}
-DEFINE_PER_CPU(bool, cpu_dead_idle);
-
/*
* Generic idle loop implementation
*
@@ -224,8 +222,7 @@ static void cpu_idle_loop(void)
if (cpu_is_offline(smp_processor_id())) {
rcu_cpu_notify(NULL, CPU_DYING_IDLE,
(void *)(long)smp_processor_id());
- smp_mb(); /* all activity before dead. */
- this_cpu_write(cpu_dead_idle, true);
+ cpuhp_report_idle_dead();
arch_cpu_idle_dead();
}
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[patch 00/20] cpu/hotplug: Core infrastructure for cpu hotplug rework Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[patch 14/20] cpu/hotplug: Split out the state walk into functions Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Split out the state walk into functions tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 17/20] arch/hotplug: Call into idle with a proper state Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] arch/hotplug: Call into idle with a proper state tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 04/20] cpu/hotplug: Split out cpu down functions Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Split out cpu down functions tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Split out cpu down functions "Srivatsa S. Bhat" <srivatsa@csail.mit.edu> - 2016-03-03 00:10 +0100
[patch 03/20] cpu/hotplug: Restructure cpu_up code Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Restructure cpu_up code tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Restructure cpu_up code "Srivatsa S. Bhat" <srivatsa@csail.mit.edu> - 2016-03-03 00:00 +0100
[patch 16/20] cpu/hotplug: Move online calls to hotplugged cpu Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Move online calls to hotplugged cpu tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 02/20] cpu/hotplug: Restructure FROZEN state handling Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Restructure FROZEN state handling tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Restructure FROZEN state handling "Srivatsa S. Bhat" <srivatsa@csail.mit.edu> - 2016-03-03 00:10 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Restructure FROZEN state handling "Srivatsa S. Bhat" <srivatsa@csail.mit.edu> - 2016-03-03 00:50 +0100
[patch 11/20] cpu/hotplug: Implement setup/removal interface Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Implement setup/removal interface tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 12/20] cpu/hotplug: Move scheduler cpu_online notifier to hotplug core Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Move scheduler cpu_online notifier to hotplug core tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 18/20] cpu/hotplug: Let upcoming cpu bring itself fully up Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Let upcoming cpu bring itself fully up tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [patch 18/20] cpu/hotplug: Let upcoming cpu bring itself fully up Richard Cochran <richardcochran@gmail.com> - 2016-03-02 18:30 +0100
[patch 15/20] cpu/hotplug: Create hotplug threads Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Create hotplug threads tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 09/20] cpu/hotplug: Add sysfs state interface Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Add sysfs state interface tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Add sysfs state interface Peter Zijlstra <peterz@infradead.org> - 2016-03-02 13:50 +0100
[patch 06/20] cpu/hotplug: Convert to a state machine for the control processor Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Convert to a state machine for the control processor tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Convert to a state machine for the control processor Peter Zijlstra <peterz@infradead.org> - 2016-03-02 12:30 +0100
[patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
Re: [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-02-27 03:20 +0100
Re: [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-02-27 03:30 +0100
Re: [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call Thomas Gleixner <tglx@linutronix.de> - 2016-02-27 08:50 +0100
Re: [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-02-27 12:10 +0100
Re: [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call Thomas Gleixner <tglx@linutronix.de> - 2016-02-27 12:40 +0100
Re: [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-02-27 17:40 +0100
[tip:smp/hotplug] rcu: Make CPU_DYING_IDLE an explicit call tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
Re: [tip:smp/hotplug] rcu: Make CPU_DYING_IDLE an explicit call "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-03-02 21:20 +0100
Re: [tip:smp/hotplug] rcu: Make CPU_DYING_IDLE an explicit call Thomas Gleixner <tglx@linutronix.de> - 2016-03-03 08:40 +0100
[tip:smp/hotplug] cpu/hotplug: Plug death reporting race tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-03 11:10 +0100
Re: [tip:smp/hotplug] cpu/hotplug: Plug death reporting race "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-03-03 15:20 +0100
[patch 08/20] cpu/hotplug: Hand in target state to _cpu_up/down Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Hand in target state to _cpu_up/down tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 19/20] cpu/hotplug: Make wait for dead cpu completion based Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 19:50 +0100
[tip:smp/hotplug] cpu/hotplug: Make wait for dead cpu completion based tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 07/20] cpu/hotplug: Convert the hotplugged cpu work to a state machine Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 20:00 +0100
[tip:smp/hotplug] cpu/hotplug: Convert the hotplugged cpu work to a state machine tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-03-01 21:00 +0100
[patch 01/20] idle: Move x86ism out of generic code Thomas Gleixner <tglx@linutronix.de> - 2016-02-26 20:00 +0100
Re: [patch 01/20] idle: Move x86ism out of generic code Brian Gerst <brgerst@gmail.com> - 2016-02-27 21:30 +0100
Re: [patch 01/20] idle: Move x86ism out of generic code Thomas Gleixner <tglx@linutronix.de> - 2016-02-29 20:40 +0100
Re: [patch 01/20] idle: Move x86ism out of generic code Will Deacon <will.deacon@arm.com> - 2016-02-29 20:50 +0100
Re: [patch 01/20] idle: Move x86ism out of generic code Thomas Gleixner <tglx@linutronix.de> - 2016-02-29 21:10 +0100
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