Re: [Qemu-devel] [RFC PATCH v1 3/4] numa: Store boot memory address range in node_info

[Eduardo Habkost]

On Fri, Jun 12, 2015 at 02:30:27PM +0530, Bharata B Rao wrote:
> Store memory address range information of boot memory  in address
> range list of numa_info.
> 
> This helps to have a common NUMA node lookup by address function that
> works for both boot time memory and hotplugged memory.
> 
> Signed-off-by: Bharata B Rao <address@hidden>
> ---
>  numa.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/numa.c b/numa.c
> index 27ca743..d67b1fb 100644
> --- a/numa.c
> +++ b/numa.c
> @@ -75,6 +75,26 @@ void numa_unset_mem_node_id(ram_addr_t addr, uint64_t 
> size, uint32_t node)
>      }
>  }
>  
> +static void numa_set_mem_ranges(void)
> +{
> +    int i;
> +    ram_addr_t mem_start, mem_end_prev;
> +
> +    /*
> +     * Deduce start address of each node and use it to store
> +     * the address range info in numa_info address range list
> +     */
> +    for (i = 0; i < nb_numa_nodes; i++) {
> +        if (i) {
> +            mem_start = mem_end_prev;
> +        } else {
> +            mem_start = 0;
> +        }

You could simply initialize mem_end_prev=0 before entering the loop,
instead.

Actually, you don't even need the mem_end_prev variable:

    int i;
    ram_addr_t mem_start = 0;

    for (i = 0; i < nb_numa_nodes; i++) {
        numa_set_mem_node_id(mem_start, numa_info[i].node_mem, i);
        mem_start = mem_start + numa_info[i].node_mem;
    }

I was going to suggest moving this to
memory_region_allocate_system_memory() instead (that already has a loop
calculating the start address for each NUMA node), but the problem is
that allocate_system_memory_nonnuma() may be called even if using NUMA
if no memdevs are used. So this can be done later, after refactoring
memory_region_allocate_system_memory() to have a single memory
allocation code path.


> +        mem_end_prev = mem_start + numa_info[i].node_mem;
> +        numa_set_mem_node_id(mem_start, numa_info[i].node_mem, i);
> +    }
> +}
> +
>  static void numa_node_parse(NumaNodeOptions *node, QemuOpts *opts, Error 
> **errp)
>  {
>      uint16_t nodenr;
> @@ -300,6 +320,8 @@ void parse_numa_opts(MachineClass *mc)
>              QLIST_INIT(&numa_info[i].addr);
>          }
>  
> +        numa_set_mem_ranges();
> +
>          for (i = 0; i < nb_numa_nodes; i++) {
>              if (!bitmap_empty(numa_info[i].node_cpu, MAX_CPUMASK_BITS)) {
>                  break;
> -- 
> 2.1.0
> 

-- 
Eduardo