linux-kernel - Re: [PATCH v4] x86,sched: allow topologies where NUMA nodes share an LLC

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Date:   Wed, 4 Apr 2018 10:24:49 -0700
From:   Tim Chen <tim.c.chen@...ux.intel.com>
To:     Alison Schofield <alison.schofield@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        "H. Peter Anvin" <hpa@...ux.intel.com>,
        Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        David Rientjes <rientjes@...gle.com>,
        Igor Mammedov <imammedo@...hat.com>,
        Prarit Bhargava <prarit@...hat.com>, brice.goglin@...il.com,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] x86,sched: allow topologies where NUMA nodes share an
 LLC

On 04/03/2018 02:12 PM, Alison Schofield wrote:

> +
> +	/*
> +	 * topology_sane() considers LLCs that span NUMA nodes to be
> +	 * insane and will display a warning message. Bypass the call
> +	 * to topology_sane() for snc_cpu's to avoid that warning.
> +	 */
> +
> +	if (!topology_same_node(c, o) && x86_match_cpu(snc_cpu)) {
> +		/* Indicate that package has NUMA nodes inside: */
> +		x86_has_numa_in_package = true;

Why does the x86_has_numa_in_package has to be set here when it would have
been done later in set_cpu_sibling_map?

> +
> +		/*
> +		 * false means 'c' does not share the LLC of 'o'.
> +		 * Note: this decision gets reflected all the way
> +		 * out to userspace.
> +		 */
> +
> +		return false;

Thanks.

Tim