From: Nicholas Piggin <npiggin@gmail.com>
To: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Michael Neuling <mikey@neuling.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"Shreyas B. Prabhu" <shreyasbp@gmail.com>,
Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Anton Blanchard <anton@samba.org>,
Balbir Singh <bsingharora@gmail.com>,
Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [v2 PATCH 3/4] powernv:idle: Don't override default/deepest directly in kernel
Date: Tue, 21 Mar 2017 02:39:34 +1000 [thread overview]
Message-ID: <20170321023934.1a9b84f6@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <84bfbacbd0ab98dd82241292a29e4d5d1bb456c6.1490024477.git.ego@linux.vnet.ibm.com>
On Mon, 20 Mar 2017 21:24:17 +0530
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com> wrote:
> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
>
> Currently during idle-init on power9, if we don't find suitable stop
> states in the device tree that can be used as the
> default_stop/deepest_stop, we set stop0 (ESL=1,EC=1) as the default
> stop state psscr to be used by power9_idle and deepest stop state
> which is used by CPU-Hotplug.
>
> However, if the platform firmware has not configured or enabled a stop
> state, the kernel should not make any assumptions and fallback to a
> default choice.
>
> If the kernel uses a stop state that is not configured by the platform
> firmware, it may lead to further failures which should be avoided.
>
> In this patch, we modify the init code to ensure that the kernel uses
> only the stop states exposed by the firmware through the device
> tree. When a suitable default stop state isn't found, we disable
> ppc_md.power_save for power9. Similarly, when a suitable
> deepest_stop_state is not found in the device tree exported by the
> firmware, fall back to the default busy-wait loop in the CPU-Hotplug
> code.
>
> [Changelog written with inputs from svaidy@linux.vnet.ibm.com]
>
> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> ---
> arch/powerpc/platforms/powernv/idle.c | 35 ++++++++++++++++++-----------------
> 1 file changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index f335e0f..63ade78 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -147,7 +147,6 @@ u32 pnv_get_supported_cpuidle_states(void)
> }
> EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states);
>
> -
> static void pnv_fastsleep_workaround_apply(void *info)
>
> {
> @@ -241,8 +240,9 @@ static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600,
> * The default stop state that will be used by ppc_md.power_save
> * function on platforms that support stop instruction.
> */
> -u64 pnv_default_stop_val;
> -u64 pnv_default_stop_mask;
> +static u64 pnv_default_stop_val;
> +static u64 pnv_default_stop_mask;
> +static bool default_stop_found;
>
> /*
> * Used for ppc_md.power_save which needs a function with no parameters
> @@ -262,8 +262,9 @@ static void power9_idle(void)
> * psscr value and mask of the deepest stop idle state.
> * Used when a cpu is offlined.
> */
> -u64 pnv_deepest_stop_psscr_val;
> -u64 pnv_deepest_stop_psscr_mask;
> +static u64 pnv_deepest_stop_psscr_val;
> +static u64 pnv_deepest_stop_psscr_mask;
> +static bool deepest_stop_found;
Aha you have made them static. Nitpick withdrawn :)
The log messages look good now.
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
next prev parent reply other threads:[~2017-03-20 16:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-20 15:54 [v2 PATCH 0/4] powernv:idle: Fixes for CPU-Hotplug on POWER DD1.0 Gautham R. Shenoy
2017-03-20 15:54 ` [v2 PATCH 1/4] powernv: Move CPU-Offline idle state invocation from smp.c to idle.c Gautham R. Shenoy
2017-03-20 16:35 ` Nicholas Piggin
2017-03-22 5:41 ` Gautham R Shenoy
2017-03-20 15:54 ` [v2 PATCH 2/4] powernv:smp: Add busy-wait loop as fall back for CPU-Hotplug Gautham R. Shenoy
2017-03-20 15:54 ` [v2 PATCH 3/4] powernv:idle: Don't override default/deepest directly in kernel Gautham R. Shenoy
2017-03-20 16:39 ` Nicholas Piggin [this message]
2017-03-22 5:43 ` Gautham R Shenoy
2017-03-20 15:54 ` [v2 PATCH 4/4] powernv: Recover correct PACA on wakeup from a stop on P9 DD1 Gautham R. Shenoy
2017-03-20 16:59 ` Nicholas Piggin
2017-03-22 3:29 ` Nicholas Piggin
2017-03-22 5:58 ` Gautham R Shenoy
2017-03-22 8:30 ` Nicholas Piggin
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