linux-kernel - Re: [PATCH v6 2/2] powerpc: Use cpu_smallcore_sibling

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Date:   Thu, 9 Aug 2018 06:26:57 -0700
From:   Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:     "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Neuling <mikey@...ling.org>,
        Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
        Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>,
        Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>,
        "Oliver O'Halloran" <oohall@...il.com>,
        Nicholas Piggin <npiggin@...il.com>,
        Murilo Opsfelder Araujo <muriloo@...ux.ibm.com>,
        Anton Blanchard <anton@...ba.org>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 2/2] powerpc: Use cpu_smallcore_sibling_mask at SMT
 level on bigcores

* Gautham R. Shenoy <ego@...ux.vnet.ibm.com> [2018-08-09 11:02:08]:

> 
> 3) ppc64_cpu --smt=2
>    SMT domain ceases to exist as each domain consists of just one
>    group.
> 

When seen in isolation, the above looks as if ppc64_cpu --smt=2 o/p says
" SMT domain ceases to exist...."

> @@ -999,7 +1012,17 @@ static void add_cpu_to_masks(int cpu)
>  {
>  	int first_thread = cpu_first_thread_sibling(cpu);
>  	int chipid = cpu_to_chip_id(cpu);
> -	int i;
> +
> +	struct thread_groups tg;
> +	int i, cpu_group_start = -1;
> +
> +	if (has_big_cores) {
> +		struct device_node *dn = of_get_cpu_node(cpu, NULL);
> +

Not checking for validity of dn and no of_node_puts?

> +		parse_thread_groups(dn, &tg);
> +		cpu_group_start = get_cpu_thread_group_start(cpu, &tg);
> +		cpumask_set_cpu(cpu, cpu_smallcore_sibling_mask(cpu));
> +	}
> 
>  	/*
>  	 * This CPU will not be in the online mask yet so we need to manually

The rest looks good