mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-29 13:53:33 +00:00
54 lines
1.5 KiB
C
54 lines
1.5 KiB
C
|
#include <linux/init.h>
|
||
|
|
#include <linux/smp.h>
|
||
|
|
|
||
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
||
|
|
|
||
|
|
int additional_cpus __initdata = -1;
|
||
|
|
|
||
|
|
static __init int setup_additional_cpus(char *s)
|
||
|
|
{
|
||
|
|
return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
|
||
|
|
}
|
||
|
|
early_param("additional_cpus", setup_additional_cpus);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* cpu_possible_map should be static, it cannot change as cpu's
|
||
|
|
* are onlined, or offlined. The reason is per-cpu data-structures
|
||
|
|
* are allocated by some modules at init time, and dont expect to
|
||
|
|
* do this dynamically on cpu arrival/departure.
|
||
|
|
* cpu_present_map on the other hand can change dynamically.
|
||
|
|
* In case when cpu_hotplug is not compiled, then we resort to current
|
||
|
|
* behaviour, which is cpu_possible == cpu_present.
|
||
|
|
* - Ashok Raj
|
||
|
|
*
|
||
|
|
* Three ways to find out the number of additional hotplug CPUs:
|
||
|
|
* - If the BIOS specified disabled CPUs in ACPI/mptables use that.
|
||
|
|
* - The user can overwrite it with additional_cpus=NUM
|
||
|
|
* - Otherwise don't reserve additional CPUs.
|
||
|
|
* We do this because additional CPUs waste a lot of memory.
|
||
|
|
* -AK
|
||
|
|
*/
|
||
|
|
__init void prefill_possible_map(void)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
int possible;
|
||
|
|
|
||
|
|
if (additional_cpus == -1) {
|
||
|
|
if (disabled_cpus > 0)
|
||
|
|
additional_cpus = disabled_cpus;
|
||
|
|
else
|
||
|
|
additional_cpus = 0;
|
||
|
|
}
|
||
|
|
possible = num_processors + additional_cpus;
|
||
|
|
if (possible > NR_CPUS)
|
||
|
|
possible = NR_CPUS;
|
||
|
|
|
||
|
|
printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
|
||
|
|
possible, max_t(int, possible - num_processors, 0));
|
||
|
|
|
||
|
|
for (i = 0; i < possible; i++)
|
||
|
|
cpu_set(i, cpu_possible_map);
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|