Re: [patch] x86: set hotpluggable nodes in nodes_possible_map

[Yinghai Lu <yinghai@kernel.org>]

On 01/20/2010 12:10 PM, David Rientjes wrote:
> On Thu, 21 Jan 2010, Haicheng Li wrote:
> 
>> let's add more changes to fix naming issue as well since it's too confusing
>> for people to understand
>> the code logic. how about below patch?
> 
> That should be a seperate change; there's a bugfix here (my patch) and 
> then a cleanup patch that you could make incrementally on mine.  I don't 
> personally like the name "rest_nodes_parsed" since it's poor English, I 
> suggest renaming nodes_parsed to mem_nodes_parsed as I originally asked 
> and then cpu_nodes_parsed to acpi_nodes_parsed or something similiar.
> 
> Ingo, the following is my bugfix patch that addresses the issue at 
> http://patchwork.kernel.org/patch/69499.  Haicheng, can we add your 
> tested-by line?
> 
> 
> 
> x86: set hotpluggable nodes in nodes_possible_map
> 
> nodes_possible_map does not currently include nodes that have SRAT
> entries that are all ACPI_SRAT_MEM_HOT_PLUGGABLE since the bit is cleared
> in nodes_parsed if it does not have an online address range.
> 
> Unequivocally setting the bit in nodes_parsed is insufficient since
> existing code, such as acpi_get_nodes(), assumes all nodes in the map
> have online address ranges.  In fact, all code using nodes_parsed assumes
> such nodes represent an address range of online memory.
> 
> nodes_possible_map is created by unioning nodes_parsed and
> cpu_nodes_parsed; the former represents nodes with online memory and the
> latter represents memoryless nodes.  We now set the bit for hotpluggable
> nodes in cpu_nodes_parsed so that it also gets set in nodes_possible_map.
> 
> Signed-off-by: David Rientjes <rientjes@google.com>
> ---
>  arch/x86/mm/srat_64.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 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
> @@ -229,9 +229,11 @@ update_nodes_add(int node, unsigned long start, unsigned long end)
>  			printk(KERN_ERR "SRAT: Hotplug zone not continuous. Partly ignored\n");
>  	}
>  
> -	if (changed)
> +	if (changed) {
> +		node_set(node, cpu_nodes_parsed);
>  		printk(KERN_INFO "SRAT: hot plug zone found %Lx - %Lx\n",
>  				 nd->start, nd->end);
> +	}
>  }
>  
>  /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */

        if (ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) {
                update_nodes_add(node, start, end);
                /* restore nodes[node] */
                *nd = oldnode;
                if ((nd->start | nd->end) == 0)
                        node_clear(node, nodes_parsed);
        }

removing clearing with nodes_parsed is not working?

YH