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From: Thomas Gleixner <tglx@linutronix.de>
To: Yicong Yang <yangyicong@huawei.com>,
	catalin.marinas@arm.com, will@kernel.org, sudeep.holla@arm.com,
	peterz@infradead.org, mpe@ellerman.id.au,
	linux-arm-kernel@lists.infradead.org, mingo@redhat.com,
	bp@alien8.de, dave.hansen@linux.intel.com,
	pierre.gondois@arm.com, dietmar.eggemann@arm.com
Cc: linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, morten.rasmussen@arm.com,
	msuchanek@suse.de, gregkh@linuxfoundation.org, rafael@kernel.org,
	jonathan.cameron@huawei.com, prime.zeng@hisilicon.com,
	linuxarm@huawei.com, yangyicong@hisilicon.com, xuwei5@huawei.com,
	guohanjun@huawei.com
Subject: Re: [PATCH v7 1/4] cpu/SMT: Provide a default topology_is_primary_thread()
Date: Wed, 30 Oct 2024 15:55:17 +0100	[thread overview]
Message-ID: <87ttcty71m.ffs@tglx> (raw)
In-Reply-To: <20241030125415.18994-2-yangyicong@huawei.com>

On Wed, Oct 30 2024 at 20:54, Yicong Yang wrote:
>  
> +#ifndef topology_is_primary_thread
> +#define topology_is_primary_thread topology_is_primary_thread

Please do not glue defines and functions together w/o a newline in between.

> +static inline bool topology_is_primary_thread(unsigned int cpu)
> +{
> +	/*
> +	 * On SMT hotplug the primary thread of the SMT won't be disabled.
> +	 * Architectures do have a special primary thread (e.g. x86) need
> +	 * to override this function. Otherwise just make the first thread
> +	 * in the SMT as the primary thread.
> +	 */
> +	return cpu == cpumask_first(topology_sibling_cpumask(cpu));

How is that supposed to work? Assume both siblings are offline, then the
sibling mask is empty and you can't boot the CPU anymore.

Thanks,

        tglx


  reply	other threads:[~2024-10-30 14:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-30 12:54 [PATCH v7 0/4] Support SMT control on arm64 Yicong Yang
2024-10-30 12:54 ` [PATCH v7 1/4] cpu/SMT: Provide a default topology_is_primary_thread() Yicong Yang
2024-10-30 14:55   ` Thomas Gleixner [this message]
2024-10-31 12:17     ` Yicong Yang
2024-10-31 13:33       ` Thomas Gleixner
2024-11-01  3:18         ` Yicong Yang
2024-11-01  9:31           ` Thomas Gleixner
2024-11-07 17:20       ` Pierre Gondois
2024-10-30 12:54 ` [PATCH v7 2/4] arch_topology: Support SMT control for OF based system Yicong Yang
2024-10-30 12:54 ` [PATCH v7 3/4] arm64: topology: Support SMT control on ACPI " Yicong Yang
2024-11-07 17:20   ` Pierre Gondois
2024-11-08  8:06     ` Yicong Yang
2024-10-30 12:54 ` [PATCH v7 4/4] arm64: Kconfig: Enable HOTPLUG_SMT Yicong Yang

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