Re: [Xen-devel] [PATCH v2] xl: fix vcpus to vnode assignement in config file

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Mon, 2015-07-20 at 11:30 +0200, Dario Faggioli wrote:
> In fact, right now, if the "vcpus=" list (where the
> user specifies what vcpus should be part of a vnode)
> has multiple elements, things don't work.
> E.g., the following examples all result in failure
> to create the guest:

What is the failure?

>  [ "pnode=0","size=512","vcpus=0,2","vdistances=10,20"  ]
>  [ "pnode=0","size=512","vcpus=0-1,4","vdistances=10,20"  ]
> 
> Reason is we need either a multidimentional array,
> or a bitmap, to temporary store the vcpus of a
> vnode, while parsing the vnuma config entry.

That sounds like a cure, not the reason for the failure. Please can you
explain the nature of the failure, so it becomes clear why this change
is needed.

> Let's use the latter, which happens to also make it
> easier to copy the outcome of the parsing to its
> final destination in b_info, if everything goes ok.
> 
> Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
> Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>

---
> Changes from v1:
>  * fix coding style
> ---
> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
>  tools/libxl/xl_cmdimpl.c |   34 ++++++++++++++++++----------------
>  1 file changed, 18 insertions(+), 16 deletions(-)
> 
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index 8cbf30e..b41874a 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -1076,9 +1076,7 @@ static void parse_vnuma_config(const XLU_Config 
> *config,
>      /* Temporary storage for parsed vcpus information to avoid
>       * parsing config twice. This array has num_vnuma elements.
>       */
> -    struct vcpu_range_parsed {
> -        unsigned long start, end;
> -    } *vcpu_range_parsed;
> +    libxl_bitmap *vcpu_parsed;
>  
>      libxl_physinfo_init(&physinfo);
>      if (libxl_get_physinfo(ctx, &physinfo) != 0) {
> @@ -1095,7 +1093,14 @@ static void parse_vnuma_config(const 
> XLU_Config *config,
>  
>      b_info->num_vnuma_nodes = num_vnuma;
>      b_info->vnuma_nodes = xcalloc(num_vnuma, 
> sizeof(libxl_vnode_info));
> -    vcpu_range_parsed = xcalloc(num_vnuma, 
> sizeof(*vcpu_range_parsed));
> +    vcpu_parsed = xcalloc(num_vnuma, sizeof(libxl_bitmap));
> +    for (i = 0; i < num_vnuma; i++) {
> +        libxl_bitmap_init(&vcpu_parsed[i]);
> +        if (libxl_cpu_bitmap_alloc(ctx, &vcpu_parsed[i], b_info
> ->max_vcpus)) {
> +            fprintf(stderr, "libxl_node_bitmap_alloc failed.\n");
> +            exit(1);
> +        }
> +    }
>  
>      for (i = 0; i < b_info->num_vnuma_nodes; i++) {
>          libxl_vnode_info *p = &b_info->vnuma_nodes[i];
> @@ -1165,12 +1170,14 @@ static void parse_vnuma_config(const 
> XLU_Config *config,
>                      split_string_into_string_list(value, ",", 
> &cpu_spec_list);
>                      len = libxl_string_list_length(&cpu_spec_list);
>  
> -                    for (j = 0; j < len; j++)
> +                    for (j = 0; j < len; j++) {
>                          parse_range(cpu_spec_list[j], &s, &e);
> +                        for (; s <= e; s++) {
> +                            libxl_bitmap_set(&vcpu_parsed[i], s);
> +                            max_vcpus++;
> +                        }
> +                    }
>  
> -                    vcpu_range_parsed[i].start = s;
> -                    vcpu_range_parsed[i].end   = e;
> -                    max_vcpus += (e - s + 1);
>                      libxl_string_list_dispose(&cpu_spec_list);
>                  } else if (!strcmp("vdistances", option)) {
>                      libxl_string_list vdist;
> @@ -1209,17 +1216,12 @@ static void parse_vnuma_config(const 
> XLU_Config *config,
>  
>      for (i = 0; i < b_info->num_vnuma_nodes; i++) {
>          libxl_vnode_info *p = &b_info->vnuma_nodes[i];
> -        int cpu;
>  
> -        libxl_cpu_bitmap_alloc(ctx, &p->vcpus, b_info->max_vcpus);
> -        libxl_bitmap_set_none(&p->vcpus);
> -        for (cpu = vcpu_range_parsed[i].start;
> -             cpu <= vcpu_range_parsed[i].end;
> -             cpu++)
> -            libxl_bitmap_set(&p->vcpus, cpu);
> +        libxl_bitmap_copy_alloc(ctx, &p->vcpus, &vcpu_parsed[i]);
> +        libxl_bitmap_dispose(&vcpu_parsed[i]);
>      }
>  
> -    free(vcpu_range_parsed);
> +    free(vcpu_parsed);
>  }
>  
>  static void parse_config_data(const char *config_source,
> 

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