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From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: linux@arm.linux.org.uk, mark.rutland@arm.com, dietmar.eggemann@arm.com
Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH arm] Use common outgoing-CPU-notification code
Date: Tue, 11 Jun 2019 12:24:10 -0700	[thread overview]
Message-ID: <20190611192410.GA27930@linux.ibm.com> (raw)

This commit removes the open-coded CPU-offline notification with new
common code.  In particular, this change avoids calling scheduler code
using RCU from an offline CPU that RCU is ignoring.  This is a minimal
change.  A more intrusive change might invoke the cpu_check_up_prepare()
and cpu_set_state_online() functions at CPU-online time, which would
allow onlining throw an error if the CPU did not go offline properly.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index ebc53804d57b..8687d619260f 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -267,15 +267,13 @@ int __cpu_disable(void)
 	return 0;
 }
 
-static DECLARE_COMPLETION(cpu_died);
-
 /*
  * called on the thread which is asking for a CPU to be shutdown -
  * waits until shutdown has completed, or it is timed out.
  */
 void __cpu_die(unsigned int cpu)
 {
-	if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+	if (!cpu_wait_death(cpu, 5)) {
 		pr_err("CPU%u: cpu didn't die\n", cpu);
 		return;
 	}
@@ -322,7 +320,7 @@ void arch_cpu_idle_dead(void)
 	 * this returns, power and/or clocks can be removed at any point
 	 * from this CPU and its cache by platform_cpu_kill().
 	 */
-	complete(&cpu_died);
+	(void)cpu_report_death();
 
 	/*
 	 * Ensure that the cache lines associated with that completion are


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WARNING: multiple messages have this Message-ID (diff)
From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: linux@arm.linux.org.uk, mark.rutland@arm.com, dietmar.eggemann@arm.com
Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH arm] Use common outgoing-CPU-notification code
Date: Tue, 11 Jun 2019 12:24:10 -0700	[thread overview]
Message-ID: <20190611192410.GA27930@linux.ibm.com> (raw)

This commit removes the open-coded CPU-offline notification with new
common code.  In particular, this change avoids calling scheduler code
using RCU from an offline CPU that RCU is ignoring.  This is a minimal
change.  A more intrusive change might invoke the cpu_check_up_prepare()
and cpu_set_state_online() functions at CPU-online time, which would
allow onlining throw an error if the CPU did not go offline properly.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index ebc53804d57b..8687d619260f 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -267,15 +267,13 @@ int __cpu_disable(void)
 	return 0;
 }
 
-static DECLARE_COMPLETION(cpu_died);
-
 /*
  * called on the thread which is asking for a CPU to be shutdown -
  * waits until shutdown has completed, or it is timed out.
  */
 void __cpu_die(unsigned int cpu)
 {
-	if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+	if (!cpu_wait_death(cpu, 5)) {
 		pr_err("CPU%u: cpu didn't die\n", cpu);
 		return;
 	}
@@ -322,7 +320,7 @@ void arch_cpu_idle_dead(void)
 	 * this returns, power and/or clocks can be removed at any point
 	 * from this CPU and its cache by platform_cpu_kill().
 	 */
-	complete(&cpu_died);
+	(void)cpu_report_death();
 
 	/*
 	 * Ensure that the cache lines associated with that completion are


             reply	other threads:[~2019-06-11 19:25 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-11 19:24 Paul E. McKenney [this message]
2019-06-11 19:24 ` [PATCH arm] Use common outgoing-CPU-notification code Paul E. McKenney
2019-06-17 11:58 ` Mark Rutland
2019-06-17 11:58   ` Mark Rutland
2019-06-17 13:06   ` Paul E. McKenney
2019-06-17 13:06     ` Paul E. McKenney
2019-06-26 16:42     ` Mark Rutland
2019-06-26 16:42       ` Mark Rutland
2019-06-26 17:49       ` Paul E. McKenney
2019-06-26 17:49         ` Paul E. McKenney

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