Re: [Xen-devel] [RFC PATCH v1 11/21] ARM: NUMA: Add fallback on NUMA failure

[Julien Grall <julien.grall@xxxxxxx>]

Hello Vijay,

On 09/02/17 15:57, vijay.kilari@xxxxxxxxx wrote:
> From: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxx>
>
> On NUMA initialization failure, reset all the
> NUMA structures to emulate as single node.
>
> Signed-off-by: Vijaya Kumar <Vijaya.Kumar@xxxxxxxxxx>
> ---
>  xen/arch/arm/numa.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/numa.c b/xen/arch/arm/numa.c
> index aa34c82..31dc552 100644
> --- a/xen/arch/arm/numa.c
> +++ b/xen/arch/arm/numa.c
> @@ -19,6 +19,7 @@
>  #include <xen/ctype.h>
>  #include <xen/mm.h>
>  #include <xen/nodemask.h>
> +#include <xen/pfn.h>
>  #include <asm/mm.h>
>  #include <xen/numa.h>
>  #include <asm/acpi.h>
> @@ -127,6 +128,29 @@ static int __init numa_scan_mem_nodes(void)
>      return 0;
>  }
>
> +static void __init numa_dummy_init(unsigned long start_pfn,
> +                                   unsigned long end_pfn)
This code is very similar to numa_initmem_init on x86. This is a call to 
make the code more generic.
> +{
> +    int i;
> +
> +    nodes_clear(numa_nodes_parsed);
> +    memnode_shift = BITS_PER_LONG - 1;
> +    memnodemap = _memnodemap;
> +    nodes_clear(node_online_map);
> +    node_set_online(0);
> +
> +    for ( i = 0; i < NR_CPUS; i++ )
> +        numa_set_node(i, 0);
> +
> +    node_distance = NULL;
> +    for ( i = 0; i < MAX_NUMNODES * 2; i++ )
> +        _node_distance[i] = 0;
> +
> +    cpumask_copy(&node_to_cpumask[0], cpumask_of(0));
> +    setup_node_bootmem(0, (u64)start_pfn << PAGE_SHIFT,
> +                       (u64)end_pfn << PAGE_SHIFT);
> +}
> +
>  static int __init numa_initmem_init(void)
>  {
>      if ( !numa_mem_init() )
> @@ -151,7 +175,9 @@ void __init init_cpu_to_node(void)
>
>  int __init numa_init(void)
I would make numa_initmem_init from x86 generic and have an arch 
specific function called from there.
>  {
> -    int i, ret = 0;
> +    int i, bank, ret = 0;
> +    paddr_t ram_start = ~0;
> +    paddr_t ram_end = 0;
>
>      if ( numa_off )
>          goto no_numa;
> @@ -164,8 +190,28 @@ int __init numa_init(void)
>      if ( !ret )
>          ret = numa_initmem_init();
>
> +    if ( !ret )
> +        return 0;
> +
>  no_numa:
> -    return ret;
> +    for ( bank = 0 ; bank < bootinfo.mem.nr_banks; bank++ )
> +    {
> +        paddr_t bank_start = bootinfo.mem.bank[bank].start;
> +        paddr_t bank_end = bank_start + bootinfo.mem.bank[bank].size;
> +
> +        ram_start = min(ram_start, bank_start);
> +        ram_end = max(ram_end, bank_end);
> +    }
I am sure this could be done in setup.c rather than here.

> +
> +    printk(XENLOG_INFO "%s\n",
> +           numa_off ? "NUMA turned off" : "No NUMA configuration found");
> +
> +    printk(XENLOG_INFO "Faking a node at %016"PRIx64"-%016"PRIx64"\n",
> +           (u64)ram_start, (u64)ram_end);
> +
> +    numa_dummy_init(PFN_UP(ram_start),PFN_DOWN(ram_end));
> +
> +    return 0;
>  }
>
>  int __init arch_numa_setup(char *opt)
Regards,

--
Julien Grall

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