x86: adjust types in smpcommon_32.c
[linux-2.6-block.git] / arch / x86 / kernel / smpboot.c
CommitLineData
68a1c3f8
GC
1#include <linux/init.h>
2#include <linux/smp.h>
3
4#ifdef CONFIG_HOTPLUG_CPU
5
6int additional_cpus __initdata = -1;
7
8static __init int setup_additional_cpus(char *s)
9{
10 return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
11}
12early_param("additional_cpus", setup_additional_cpus);
13
14/*
15 * cpu_possible_map should be static, it cannot change as cpu's
16 * are onlined, or offlined. The reason is per-cpu data-structures
17 * are allocated by some modules at init time, and dont expect to
18 * do this dynamically on cpu arrival/departure.
19 * cpu_present_map on the other hand can change dynamically.
20 * In case when cpu_hotplug is not compiled, then we resort to current
21 * behaviour, which is cpu_possible == cpu_present.
22 * - Ashok Raj
23 *
24 * Three ways to find out the number of additional hotplug CPUs:
25 * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
26 * - The user can overwrite it with additional_cpus=NUM
27 * - Otherwise don't reserve additional CPUs.
28 * We do this because additional CPUs waste a lot of memory.
29 * -AK
30 */
31__init void prefill_possible_map(void)
32{
33 int i;
34 int possible;
35
36 if (additional_cpus == -1) {
37 if (disabled_cpus > 0)
38 additional_cpus = disabled_cpus;
39 else
40 additional_cpus = 0;
41 }
42 possible = num_processors + additional_cpus;
43 if (possible > NR_CPUS)
44 possible = NR_CPUS;
45
46 printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
47 possible, max_t(int, possible - num_processors, 0));
48
49 for (i = 0; i < possible; i++)
50 cpu_set(i, cpu_possible_map);
51}
52#endif
53