Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

[uclinux-h8/linux.git] / arch / mips / kernel / smp.c

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index faa46eb..d0744cc 100644 (file)
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -63,6 +63,13 @@ EXPORT_SYMBOL(cpu_sibling_map);
 cpumask_t cpu_core_map[NR_CPUS] __read_mostly;
 EXPORT_SYMBOL(cpu_core_map);
 
+/*
+ * A logcal cpu mask containing only one VPE per core to
+ * reduce the number of IPIs on large MT systems.
+ */
+cpumask_t cpu_foreign_map __read_mostly;
+EXPORT_SYMBOL(cpu_foreign_map);
+
 /* representing cpus for which sibling maps can be computed */
 static cpumask_t cpu_sibling_setup_map;
 
@@ -103,6 +110,29 @@ static inline void set_cpu_core_map(int cpu)
        }
 }
 
+/*
+ * Calculate a new cpu_foreign_map mask whenever a
+ * new cpu appears or disappears.
+ */
+static inline void calculate_cpu_foreign_map(void)
+{
+       int i, k, core_present;
+       cpumask_t temp_foreign_map;
+
+       /* Re-calculate the mask */
+       for_each_online_cpu(i) {
+               core_present = 0;
+               for_each_cpu(k, &temp_foreign_map)
+                       if (cpu_data[i].package == cpu_data[k].package &&
+                           cpu_data[i].core == cpu_data[k].core)
+                               core_present = 1;
+               if (!core_present)
+                       cpumask_set_cpu(i, &temp_foreign_map);
+       }
+
+       cpumask_copy(&cpu_foreign_map, &temp_foreign_map);
+}
+
 struct plat_smp_ops *mp_ops;
 EXPORT_SYMBOL(mp_ops);
 
@@ -146,6 +176,8 @@ asmlinkage void start_secondary(void)
        set_cpu_sibling_map(cpu);
        set_cpu_core_map(cpu);
 
+       calculate_cpu_foreign_map();
+
        cpumask_set_cpu(cpu, &cpu_callin_map);
 
        synchronise_count_slave(cpu);
@@ -173,9 +205,18 @@ void __irq_entry smp_call_function_interrupt(void)
 static void stop_this_cpu(void *dummy)
 {
        /*
-        * Remove this CPU:
+        * Remove this CPU. Be a bit slow here and
+        * set the bits for every online CPU so we don't miss
+        * any IPI whilst taking this VPE down.
         */
+
+       cpumask_copy(&cpu_foreign_map, cpu_online_mask);
+
+       /* Make it visible to every other CPU */
+       smp_mb();
+
        set_cpu_online(smp_processor_id(), false);
+       calculate_cpu_foreign_map();
        local_irq_disable();
        while (1);
 }
@@ -197,6 +238,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
        mp_ops->prepare_cpus(max_cpus);
        set_cpu_sibling_map(0);
        set_cpu_core_map(0);
+       calculate_cpu_foreign_map();
 #ifndef CONFIG_HOTPLUG_CPU
        init_cpu_present(cpu_possible_mask);
 #endif