Re: [PATCH] sched: reduce sched_domain_topology space

[Namhyung Kim <namhyung@kernel.org>]

Hi, liguang

On Tue, 15 Jan 2013 17:15:18 +0800, liguang wrote:
> sched_domain_topology space was allocated by the size
> ARRAY_SIZE(default_topology) + sched_domains_numa_levels,
> suppose CONFIG_SCHED_SMT, CONFIG_SCHED_MC were y,
> "static struct sched_domain_topology_level default_topology[] = {
>          { sd_init_SIBLING, cpu_smt_mask, },
>          { sd_init_MC, cpu_coregroup_mask, },
>          { sd_init_CPU, cpu_cpu_mask, },
>          { NULL, },
> };"
> then, ARRAY_SIZE(default_topology) equals to 4,
> default_topology's NULL entry was accounted,
> but, the following allocation for other sched_domains_numa_levels
> entries was startd at 3(for default_topology[3].init is NULL),
> so, 1 entry was forgot.

I don't think it's forgotten.

The sched_domain_topology still needs NULL entry at the end.  So what
the current code does is to set up following sched_domain_topology:

{ default_topology (without last NULL entry), numa topology, NULL }

Thanks,
Namhyung