[libvirt] [PATCH 09/10] nodeinfo: Use a bitmap to keep track of node CPUs

[Peter Krempa]

On Fri, Jul 17, 2015 at 18:13:28 +0200, Andrea Bolognani wrote:
> Keep track of what CPUs belong to the current node while walking
> through the sysfs node entry, so we don't need to do it a second
> time immediately afterwards.
> 
> This also allows us to loop through all CPUs that are part of a
> node in guaranteed ascending order, which is something that is
> required for some upcoming changes.
> ---
>  src/nodeinfo.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
> 

...

> @@ -480,13 +490,11 @@ virNodeParseNode(const char *sysfs_prefix,
>          if (!(cores_maps[i] = virBitmapNew(ID_MAX + 1)))
>              goto cleanup;
>  
> -    /* iterate over all CPU's in the node */
> -    rewinddir(cpudir);
> -    while ((direrr = virDirRead(cpudir, &cpudirent, node)) > 0) {
> -        if (sscanf(cpudirent->d_name, "cpu%u", &cpu) != 1)
> -            continue;
> +    /* Iterate over all CPUs in the node, in ascending order */
> +    for (cpu = 0; cpu < npresent_cpus; cpu++) {
>  
> -        if (!virBitmapIsBitSet(present_cpumap, cpu))
> +        /* Skip CPUs that are not part of the current node */
> +        if (!virBitmapIsBitSet(node_cpus_map, cpu))

Perhaps you can use virBitmapNextSetBit to simplify the iteration.

>              continue;
>  
>          if (!virBitmapIsBitSet(online_cpus_map, cpu)) {

ACK with or without the iteration modified.

Peter
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