[PATCH 19/22] ARM: CPU hotplug: move cpu_killed completion to core code

[Vincent Guittot]

> Date: Fri, 03 Dec 2010 20:25:22 +0000
> From: Russell King - ARM Linux <linux at arm.linux.org.uk>
> To: linux-arm-kernel at lists.infradead.org,       Catalin Marinas
>        <catalin.marinas at arm.com>
> Subject: [PATCH 19/22] ARM: CPU hotplug: move cpu_killed completion to
>        core    code
> Message-ID: <E1POcC2-0007sD-I3 at rmk-PC.arm.linux.org.uk>
> Content-Type: text/plain; charset="us-ascii"
>
> We always need to wait for the dying CPU to reach a safe state before
> taking it down, irrespective of the requirements of the platform.
> Move the completion code into the ARM SMP hotplug code rather than
> having each platform re-implement this.
>
> Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> ---
>  arch/arm/kernel/smp.c              |   14 +++++++++++++-
>  arch/arm/mach-omap2/omap-hotplug.c |    8 ++------
>  arch/arm/mach-realview/hotplug.c   |    8 +-------
>  arch/arm/mach-s5pv310/hotplug.c    |    8 +-------
>  arch/arm/mach-tegra/hotplug.c      |    8 +-------
>  arch/arm/mach-ux500/hotplug.c      |    8 +-------
>  6 files changed, 19 insertions(+), 35 deletions(-)
>
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index 1f1de2b..bebe3bd 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -24,6 +24,7 @@
>  #include <linux/irq.h>
>  #include <linux/percpu.h>
>  #include <linux/clockchips.h>
> +#include <linux/completion.h>
>
>  #include <asm/atomic.h>
>  #include <asm/cacheflush.h>
> @@ -238,12 +239,20 @@ 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, 5000)) {

Shouldn't you test the opposite like with platform_cpu_kill below ?


> +               printk(KERN_ERR "CPU%u: cpu didn't die\n", cpu);
> +               return;
> +       }
> +       printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
> +
>        if (!platform_cpu_kill(cpu))
>                printk("CPU%u: unable to kill\n", cpu);
>  }
> @@ -263,9 +272,12 @@ void __ref cpu_die(void)
>        local_irq_disable();
>        idle_task_exit();
>
> +       /* Tell __cpu_die() that this CPU is now safe to dispose of */
> +       complete(&cpu_died);
> +
>        /*
>         * actual CPU shutdown procedure is at least platform (if not
> -        * CPU) specific
> +        * CPU) specific.
>         */
>        platform_cpu_die(cpu);
>
> diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c
> index 6cee456..ace979d 100644
> --- a/arch/arm/mach-omap2/omap-hotplug.c
> +++ b/arch/arm/mach-omap2/omap-hotplug.c
> @@ -17,16 +17,13 @@
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
>  #include <linux/smp.h>
> -#include <linux/completion.h>
>
>  #include <asm/cacheflush.h>
>  #include <mach/omap4-common.h>
>
> -static DECLARE_COMPLETION(cpu_killed);
> -
>  int platform_cpu_kill(unsigned int cpu)
>  {
> -       return wait_for_completion_timeout(&cpu_killed, 5000);
> +       return 1;
>  }
>
>  /*
> @@ -42,8 +39,7 @@ void platform_cpu_die(unsigned int cpu)
>                           this_cpu, cpu);
>                BUG();
>        }
> -       pr_notice("CPU%u: shutdown\n", cpu);
> -       complete(&cpu_killed);
> +
>        flush_cache_all();
>        dsb();
>
> diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c
> index f95521a..7d58c16 100644
> --- a/arch/arm/mach-realview/hotplug.c
> +++ b/arch/arm/mach-realview/hotplug.c
> @@ -11,14 +11,11 @@
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
>  #include <linux/smp.h>
> -#include <linux/completion.h>
>
>  #include <asm/cacheflush.h>
>
>  extern volatile int pen_release;
>
> -static DECLARE_COMPLETION(cpu_killed);
> -
>  static inline void cpu_enter_lowpower(void)
>  {
>        unsigned int v;
> @@ -95,7 +92,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
>
>  int platform_cpu_kill(unsigned int cpu)
>  {
> -       return wait_for_completion_timeout(&cpu_killed, 5000);
> +       return 1;
>  }
>
>  /*
> @@ -115,9 +112,6 @@ void platform_cpu_die(unsigned int cpu)
>        }
>  #endif
>
> -       printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
> -       complete(&cpu_killed);
> -
>        /*
>         * we're ready for shutdown now, so do it
>         */
> diff --git a/arch/arm/mach-s5pv310/hotplug.c b/arch/arm/mach-s5pv310/hotplug.c
> index 03652c3..d7be70a 100644
> --- a/arch/arm/mach-s5pv310/hotplug.c
> +++ b/arch/arm/mach-s5pv310/hotplug.c
> @@ -13,14 +13,11 @@
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
>  #include <linux/smp.h>
> -#include <linux/completion.h>
>
>  #include <asm/cacheflush.h>
>
>  extern volatile int pen_release;
>
> -static DECLARE_COMPLETION(cpu_killed);
> -
>  static inline void cpu_enter_lowpower(void)
>  {
>        unsigned int v;
> @@ -98,7 +95,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
>
>  int platform_cpu_kill(unsigned int cpu)
>  {
> -       return wait_for_completion_timeout(&cpu_killed, 5000);
> +       return 1;
>  }
>
>  /*
> @@ -118,9 +115,6 @@ void platform_cpu_die(unsigned int cpu)
>        }
>  #endif
>
> -       printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
> -       complete(&cpu_killed);
> -
>        /*
>         * we're ready for shutdown now, so do it
>         */
> diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c
> index 8e7f115..ecaa41c 100644
> --- a/arch/arm/mach-tegra/hotplug.c
> +++ b/arch/arm/mach-tegra/hotplug.c
> @@ -11,12 +11,9 @@
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
>  #include <linux/smp.h>
> -#include <linux/completion.h>
>
>  #include <asm/cacheflush.h>
>
> -static DECLARE_COMPLETION(cpu_killed);
> -
>  static inline void cpu_enter_lowpower(void)
>  {
>        unsigned int v;
> @@ -94,7 +91,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
>
>  int platform_cpu_kill(unsigned int cpu)
>  {
> -       return wait_for_completion_timeout(&cpu_killed, 5000);
> +       return 1;
>  }
>
>  /*
> @@ -114,9 +111,6 @@ void platform_cpu_die(unsigned int cpu)
>        }
>  #endif
>
> -       printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
> -       complete(&cpu_killed);
> -
>        /*
>         * we're ready for shutdown now, so do it
>         */
> diff --git a/arch/arm/mach-ux500/hotplug.c b/arch/arm/mach-ux500/hotplug.c
> index b782a03..7a4890b 100644
> --- a/arch/arm/mach-ux500/hotplug.c
> +++ b/arch/arm/mach-ux500/hotplug.c
> @@ -11,14 +11,11 @@
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
>  #include <linux/smp.h>
> -#include <linux/completion.h>
>
>  #include <asm/cacheflush.h>
>
>  extern volatile int pen_release;
>
> -static DECLARE_COMPLETION(cpu_killed);
> -
>  static inline void platform_do_lowpower(unsigned int cpu)
>  {
>        flush_cache_all();
> @@ -38,7 +35,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
>
>  int platform_cpu_kill(unsigned int cpu)
>  {
> -       return wait_for_completion_timeout(&cpu_killed, 5000);
> +       return 1;
>  }
>
>  /*
> @@ -58,9 +55,6 @@ void platform_cpu_die(unsigned int cpu)
>        }
>  #endif
>
> -       printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
> -       complete(&cpu_killed);
> -
>        /* directly enter low power state, skipping secure registers */
>        platform_do_lowpower(cpu);
>  }
> --
> 1.6.2.5
>
>
>