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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-12-16 14:31:26 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-12-18 17:35:18 +0100
commitd80512f87474f2dfd67ef931737659acce20fe69 (patch)
treedac6a70fa90b58bdf396292e95dced35c3caccff /arch/s390/kernel/smp.c
parent319e2e3f63c348a9b66db4667efa73178e18b17d (diff)
downloadlinux-linaro-stable-d80512f87474f2dfd67ef931737659acce20fe69.tar.gz
s390/smp: improve setup of possible cpu mask
Since under z/VM we cannot have more than 64 cpus, make sure the cpu_possible_mask does not contain more bits. This avoids wasting memory for dynamic per-cpu allocations if CONFIG_NR_CPUS is larger than 64. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/smp.c')
-rw-r--r--arch/s390/kernel/smp.c25
1 files changed, 16 insertions, 9 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index dc4a53465060..958704798f4a 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -721,18 +721,14 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
return 0;
}
-static int __init setup_possible_cpus(char *s)
-{
- int max, cpu;
+static unsigned int setup_possible_cpus __initdata;
- if (kstrtoint(s, 0, &max) < 0)
- return 0;
- init_cpu_possible(cpumask_of(0));
- for (cpu = 1; cpu < max && cpu < nr_cpu_ids; cpu++)
- set_cpu_possible(cpu, true);
+static int __init _setup_possible_cpus(char *s)
+{
+ get_option(&s, &setup_possible_cpus);
return 0;
}
-early_param("possible_cpus", setup_possible_cpus);
+early_param("possible_cpus", _setup_possible_cpus);
#ifdef CONFIG_HOTPLUG_CPU
@@ -775,6 +771,17 @@ void __noreturn cpu_die(void)
#endif /* CONFIG_HOTPLUG_CPU */
+void __init smp_fill_possible_mask(void)
+{
+ unsigned int possible, cpu;
+
+ possible = setup_possible_cpus;
+ if (!possible)
+ possible = MACHINE_IS_VM ? 64 : nr_cpu_ids;
+ for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
+ set_cpu_possible(cpu, true);
+}
+
void __init smp_prepare_cpus(unsigned int max_cpus)
{
/* request the 0x1201 emergency signal external interrupt */