Re: [PATCH] mem-hotplug: introduce movablenodes boot option for memory hotplug debugging

[tangchen <tangchen@cn.fujitsu.com>]

On 08/19/2014 06:02 PM, Xishi Qiu wrote:
> This patch introduces a new boot option "movablenodes". This parameter
> depends on movable_node, it is used for debugging memory hotplug.
> Instead SRAT specifies which memory is hotpluggable.
>
> e.g. movable_node movablenodes=1,2,4
>
> It means nodes 1,2,4 will be set to movable nodes, the other nodes are
> unmovable nodes. Usually movable nodes are parsed from SRAT table which
> offered by BIOS.

This may not work on some machines. So far as I know, there are machines
that after a reboot, node id will change. So node 1,2,4 may be not the same
nodes as before in the next boot.

Thanks.

>
> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
> ---
>   Documentation/kernel-parameters.txt |    5 ++++
>   arch/x86/mm/srat.c                  |   36 +++++++++++++++++++++++++++++++++++
>   2 files changed, 41 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 5ae8608..e072ccf 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1949,6 +1949,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>   	movable_node	[KNL,X86] Boot-time switch to enable the effects
>   			of CONFIG_MOVABLE_NODE=y. See mm/Kconfig for details.
>   
> +	movablenodes=	[KNL,X86] This parameter depends on movable_node, it
> +			is used for debugging memory hotplug. Instead SRAT
> +			specifies which memory is hotpluggable.
> +			e.g. movablenodes=1,2,4
> +
>   	MTD_Partition=	[MTD]
>   			Format: <name>,<region-number>,<size>,<offset>
>   
> diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
> index 66338a6..523e58b 100644
> --- a/arch/x86/mm/srat.c
> +++ b/arch/x86/mm/srat.c
> @@ -157,6 +157,37 @@ static inline int save_add_info(void) {return 1;}
>   static inline int save_add_info(void) {return 0;}
>   #endif
>   
> +static nodemask_t movablenodes_mask;
> +
> +static void __init parse_movablenodes_one(char *p)
> +{
> +	int node;
> +
> +	get_option(&p, &node);
> +	node_set(node, movablenodes_mask);
> +}
> +
> +static int __init parse_movablenodes_opt(char *str)
> +{
> +	nodes_clear(movablenodes_mask);
> +
> +#ifdef CONFIG_MOVABLE_NODE
> +	while (str) {
> +		char *k = strchr(str, ',');
> +
> +		if (k)
> +			*k++ = 0;
> +		parse_movablenodes_one(str);
> +		str = k;
> +	}
> +#else
> +	pr_warn("movable_node option not supported\n");
> +#endif
> +
> +	return 0;
> +}
> +early_param("movablenodes", parse_movablenodes_opt);
> +
>   /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
>   int __init
>   acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
> @@ -202,6 +233,11 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
>   		pr_warn("SRAT: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
>   			(unsigned long long)start, (unsigned long long)end - 1);
>   
> +	if (node_isset(node, movablenodes_mask) &&
> +		memblock_mark_hotplug(start, ma->length))
> +		pr_warn("SRAT debug: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
> +			(unsigned long long)start, (unsigned long long)end - 1);
> +
>   	return 0;
>   out_err_bad_srat:
>   	bad_srat();

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