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>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 1e1a03d..e9f3125 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -135,7 +135,6 @@
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UID16 if 32BIT
select HAVE_VIRT_CPU_ACCOUNTING
- select INIT_ALL_POSSIBLE
select KTIME_SCALAR if 32BIT
select MODULES_USE_ELF_RELA
select OLD_SIGACTION
diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h
index ac9bed8..1607793 100644
--- a/arch/s390/include/asm/smp.h
+++ b/arch/s390/include/asm/smp.h
@@ -31,6 +31,7 @@
extern void smp_stop_cpu(void);
extern void smp_cpu_set_polarization(int cpu, int val);
extern int smp_cpu_get_polarization(int cpu);
+extern void smp_fill_possible_mask(void);
#else /* CONFIG_SMP */
@@ -50,6 +51,7 @@
static inline void smp_yield_cpu(int cpu) { }
static inline void smp_yield(void) { }
static inline void smp_stop_cpu(void) { }
+static inline void smp_fill_possible_mask(void) { }
#endif /* CONFIG_SMP */
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 4444875..0f3d44e 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -1023,6 +1023,7 @@
setup_vmcoreinfo();
setup_lowcore();
+ smp_fill_possible_mask();
cpu_init();
s390_init_cpu_topology();
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index dc4a534..9587047 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -721,18 +721,14 @@
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 @@
#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 */