sched: Simplify build_sched_groups()

Notice that the mask being computed is the same as the domain span we
just computed. By using the domain_span we can avoid some mask
allocations and computations.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122941.925028189@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 50d5fd3..e3818f1 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6866,9 +6866,6 @@ struct s_data {
        cpumask_var_t           notcovered;
 #endif
        cpumask_var_t           nodemask;
-       cpumask_var_t           this_sibling_map;
-       cpumask_var_t           this_core_map;
-       cpumask_var_t           this_book_map;
        cpumask_var_t           send_covered;
        cpumask_var_t           tmpmask;
        struct sched_group      **sched_group_nodes;
@@ -6880,9 +6877,6 @@ enum s_alloc {
        sa_rootdomain,
        sa_tmpmask,
        sa_send_covered,
-       sa_this_book_map,
-       sa_this_core_map,
-       sa_this_sibling_map,
        sa_nodemask,
        sa_sched_group_nodes,
 #ifdef CONFIG_NUMA
@@ -7251,12 +7245,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
                free_cpumask_var(d->tmpmask); /* fall through */
        case sa_send_covered:
                free_cpumask_var(d->send_covered); /* fall through */
-       case sa_this_book_map:
-               free_cpumask_var(d->this_book_map); /* fall through */
-       case sa_this_core_map:
-               free_cpumask_var(d->this_core_map); /* fall through */
-       case sa_this_sibling_map:
-               free_cpumask_var(d->this_sibling_map); /* fall through */
        case sa_nodemask:
                free_cpumask_var(d->nodemask); /* fall through */
        case sa_sched_group_nodes:
@@ -7295,14 +7283,8 @@ static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
 #endif
        if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL))
                return sa_sched_group_nodes;
-       if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL))
-               return sa_nodemask;
-       if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL))
-               return sa_this_sibling_map;
-       if (!alloc_cpumask_var(&d->this_book_map, GFP_KERNEL))
-               return sa_this_core_map;
        if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
-               return sa_this_book_map;
+               return sa_nodemask;
        if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL))
                return sa_send_covered;
        d->rd = alloc_rootdomain();
@@ -7414,39 +7396,40 @@ static struct sched_domain *__build_smt_sched_domain(struct s_data *d,
 static void build_sched_groups(struct s_data *d, enum sched_domain_level l,
                               const struct cpumask *cpu_map, int cpu)
 {
+       struct sched_domain *sd;
+
        switch (l) {
 #ifdef CONFIG_SCHED_SMT
        case SD_LV_SIBLING: /* set up CPU (sibling) groups */
-               cpumask_and(d->this_sibling_map, cpu_map,
-                           topology_thread_cpumask(cpu));
-               if (cpu == cpumask_first(d->this_sibling_map))
-                       init_sched_build_groups(d->this_sibling_map, cpu_map,
+               sd = &per_cpu(cpu_domains, cpu).sd;
+               if (cpu == cpumask_first(sched_domain_span(sd)))
+                       init_sched_build_groups(sched_domain_span(sd), cpu_map,
                                                &cpu_to_cpu_group,
                                                d->send_covered, d->tmpmask);
                break;
 #endif
 #ifdef CONFIG_SCHED_MC
        case SD_LV_MC: /* set up multi-core groups */
-               cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu));
-               if (cpu == cpumask_first(d->this_core_map))
-                       init_sched_build_groups(d->this_core_map, cpu_map,
+               sd = &per_cpu(core_domains, cpu).sd;
+               if (cpu == cpumask_first(sched_domain_span(sd)))
+                       init_sched_build_groups(sched_domain_span(sd), cpu_map,
                                                &cpu_to_core_group,
                                                d->send_covered, d->tmpmask);
                break;
 #endif
 #ifdef CONFIG_SCHED_BOOK
        case SD_LV_BOOK: /* set up book groups */
-               cpumask_and(d->this_book_map, cpu_map, cpu_book_mask(cpu));
-               if (cpu == cpumask_first(d->this_book_map))
-                       init_sched_build_groups(d->this_book_map, cpu_map,
+               sd = &per_cpu(book_domains, cpu).sd;
+               if (cpu == cpumask_first(sched_domain_span(sd)))
+                       init_sched_build_groups(sched_domain_span(sd), cpu_map,
                                                &cpu_to_book_group,
                                                d->send_covered, d->tmpmask);
                break;
 #endif
        case SD_LV_CPU: /* set up physical groups */
-               cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map);
-               if (!cpumask_empty(d->nodemask))
-                       init_sched_build_groups(d->nodemask, cpu_map,
+               sd = &per_cpu(phys_domains, cpu).sd;
+               if (cpu == cpumask_first(sched_domain_span(sd)))
+                       init_sched_build_groups(sched_domain_span(sd), cpu_map,
                                                &cpu_to_phys_group,
                                                d->send_covered, d->tmpmask);
                break;
@@ -7502,11 +7485,8 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
                build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i);
                build_sched_groups(&d, SD_LV_BOOK, cpu_map, i);
                build_sched_groups(&d, SD_LV_MC, cpu_map, i);
-       }
-
-       /* Set up physical groups */
-       for (i = 0; i < nr_node_ids; i++)
                build_sched_groups(&d, SD_LV_CPU, cpu_map, i);
+       }
 
 #ifdef CONFIG_NUMA
        /* Set up node groups */