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Re: [PATCH 1/3] powernv:smp: Add busy-wait loop as fall back for CPU-Hotplug

From Nicholas Piggin <npiggin@gmail.com>
Newsgroups linux.kernel
Subject Re: [PATCH 1/3] powernv:smp: Add busy-wait loop as fall back for CPU-Hotplug
Date 2017-03-14 14:40 +0100
Message-ID <tkUQa-Mo-35@gated-at.bofh.it> (permalink)
References <tkrl7-4G5-3@gated-at.bofh.it> <tkrl8-4G5-7@gated-at.bofh.it>
Organization IBM

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On Mon, 13 Mar 2017 11:31:26 +0530
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com> wrote:

> [Changelog written with inputs from svaidy@linux.vnet.ibm.com]
> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

> ---
>  arch/powerpc/platforms/powernv/smp.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
> index e39e6c4..8d5b99e 100644
> --- a/arch/powerpc/platforms/powernv/smp.c
> +++ b/arch/powerpc/platforms/powernv/smp.c
> @@ -192,8 +192,16 @@ static void pnv_smp_cpu_kill_self(void)
>  		} else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
>  			   (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
>  			srr1 = power7_sleep();
> -		} else {
> +		} else if (idle_states & OPAL_PM_NAP_ENABLED) {
>  			srr1 = power7_nap(1);
> +		} else {
> +			/* This is the fallback method. We emulate snooze */
> +			while (!generic_check_cpu_restart(cpu)) {
> +				HMT_low();
> +				HMT_very_low();
> +			}
> +			srr1 = 0;
> +			HMT_medium();
>  		}
>  
>  		ppc64_runlatch_on();

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Thread

[PATCH 0/3] powernv:idle: Fixes for CPU-Hotplug on POWER DD1.0 "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-03-13 07:10 +0100
  [PATCH 2/3] powernv:idle: Don't override default/deepest directly in kernel "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-03-13 07:10 +0100
    Re: [PATCH 2/3] powernv:idle: Don't override default/deepest  directly in kernel Nicholas Piggin <npiggin@gmail.com> - 2017-03-14 15:10 +0100
      Re: [PATCH 2/3] powernv:idle: Don't override default/deepest  directly in kernel Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-03-15 12:20 +0100
  [PATCH 1/3] powernv:smp: Add busy-wait loop as fall back for CPU-Hotplug "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-03-13 07:10 +0100
    Re: [PATCH 1/3] powernv:smp: Add busy-wait loop as fall back for  CPU-Hotplug Nicholas Piggin <npiggin@gmail.com> - 2017-03-14 14:40 +0100
  [PATCH 3/3] powernv:Recover correct PACA on wakeup from a stop on P9 DD1 "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-03-13 07:10 +0100
    Re: [PATCH 3/3] powernv:Recover correct PACA on wakeup from a stop  on P9 DD1 Nicholas Piggin <npiggin@gmail.com> - 2017-03-14 15:40 +0100

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