linux-kernel - Re: [patch] x86: reduce srat verbosity in the kernel log

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Date:	Fri, 13 Nov 2009 10:53:50 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	David Rientjes <rientjes@...gle.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mike Travis <travis@....com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	Roland Dreier <rdreier@...co.com>,
	Randy Dunlap <rdunlap@...otime.net>, Tejun Heo <tj@...nel.org>,
	Andi Kleen <andi@...stfloor.org>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Yinghai Lu <yhlu.kernel@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>,
	Jack Steiner <steiner@....com>,
	Frederic Weisbecker <fweisbec@...il.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [patch] x86: reduce srat verbosity in the kernel log


* David Rientjes <rientjes@...gle.com> wrote:

> It's possible to reduce the number of SRAT messages emitted to the kernel
> log by printing each valid pxm once and then creating bitmaps to represent
> the apic ids that map to the same node.
> 
> This reduces lines such as
> 
> 	SRAT: PXM 0 -> APIC 0 -> Node 0
> 	SRAT: PXM 0 -> APIC 1 -> Node 0
> 	SRAT: PXM 1 -> APIC 2 -> Node 1
> 	SRAT: PXM 1 -> APIC 3 -> Node 1
> 
> to
> 
> 	SRAT: PXM 0 -> APIC {0-1} -> Node 0
> 	SRAT: PXM 1 -> APIC {2-3} -> Node 1
> 
> The buffer used to store the apic id list is 128 characters in length.
> If that is too small to represent all the apic id ranges that are bound
> to a single pxm, a trailing "..." is added.  APICID_LIST_LEN should be
> manually increased for such configurations.
> 
> Acked-by: Mike Travis <travis@....com>
> Signed-off-by: David Rientjes <rientjes@...gle.com>
> ---
>  arch/x86/mm/srat_64.c |   41 +++++++++++++++++++++++++++++++++++++----
>  drivers/acpi/numa.c   |    5 +++++
>  include/linux/acpi.h  |    3 ++-
>  3 files changed, 44 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c
> --- a/arch/x86/mm/srat_64.c
> +++ b/arch/x86/mm/srat_64.c
> @@ -36,6 +36,9 @@ static int num_node_memblks __initdata;
>  static struct bootnode node_memblk_range[NR_NODE_MEMBLKS] __initdata;
>  static int memblk_nodeid[NR_NODE_MEMBLKS] __initdata;
>  
> +static DECLARE_BITMAP(apicid_map, MAX_LOCAL_APIC) __initdata;
> +#define APICID_LIST_LEN	(128)
> +
>  static __init int setup_node(int pxm)
>  {
>  	return acpi_map_pxm_to_node(pxm);
> @@ -136,8 +139,6 @@ acpi_numa_x2apic_affinity_init(struct acpi_srat_x2apic_cpu_affinity *pa)
>  	apicid_to_node[apic_id] = node;
>  	node_set(node, cpu_nodes_parsed);
>  	acpi_numa = 1;
> -	printk(KERN_INFO "SRAT: PXM %u -> APIC %u -> Node %u\n",
> -	       pxm, apic_id, node);
>  }
>  
>  /* Callback for Proximity Domain -> LAPIC mapping */
> @@ -170,8 +171,40 @@ acpi_numa_processor_affinity_init(struct acpi_srat_cpu_affinity *pa)
>  	apicid_to_node[apic_id] = node;
>  	node_set(node, cpu_nodes_parsed);
>  	acpi_numa = 1;
> -	printk(KERN_INFO "SRAT: PXM %u -> APIC %u -> Node %u\n",
> -	       pxm, apic_id, node);
> +}
> +
> +void __init acpi_numa_print_srat_mapping(void)
> +{
> +	char apicid_list[APICID_LIST_LEN];
> +	int i, j;
> +
> +	for (i = 0; i < MAX_PXM_DOMAINS; i++) {
> +		int len;
> +		int nid;
> +
> +		nid = pxm_to_node(i);
> +		if (nid == NUMA_NO_NODE)
> +			continue;
> +
> +		bitmap_zero(apicid_map, MAX_LOCAL_APIC);
> +		for (j = 0; j < MAX_LOCAL_APIC; j++)
> +			if (apicid_to_node[j] == nid)
> +				set_bit(j, apicid_map);
> +
> +		if (bitmap_empty(apicid_map, MAX_LOCAL_APIC))
> +			continue;
> +
> +		/*
> +		 * If the bitmap cannot be listed in a buffer of length
> +		 * APICID_LIST_LEN, then it is suffixed with "...".
> +		 */
> +		len = bitmap_scnlistprintf(apicid_list, APICID_LIST_LEN,
> +					   apicid_map, MAX_LOCAL_APIC);
> +		pr_info("SRAT: PXM %u -> APIC {%s%s} -> Node %u\n",
> +			i, apicid_list,
> +			(len == APICID_LIST_LEN - 1) ? "..." : "",
> +			nid);
> +	}
>  }

No. As i suggested many times before, just get rid of the printouts or 
make them boot-debug-flag dependent.

	Ingo
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