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author | Glauber Costa <gcosta@redhat.com> | 2008-03-03 14:12:42 -0300 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-04-17 17:40:53 +0200 |
commit | 68a1c3f8cd893f5c3c1396fec5be7d8acac4fc93 (patch) | |
tree | 9e68b2943f67912535b649a45a659ee1fc076aa2 /arch/x86/kernel/smpboot.c | |
parent | 7b1292e2371e3ae2ac69fbb899d539ddc7b53a27 (diff) | |
download | kernel_samsung_smdk4412-68a1c3f8cd893f5c3c1396fec5be7d8acac4fc93.zip kernel_samsung_smdk4412-68a1c3f8cd893f5c3c1396fec5be7d8acac4fc93.tar.gz kernel_samsung_smdk4412-68a1c3f8cd893f5c3c1396fec5be7d8acac4fc93.tar.bz2 |
x86: move prefill_possible_map to common file
this patches moves prefill_possible_map() to smpboot.c
Right now it is x86_64-specific, but nothing intrinsically
prevents it to be used by i386
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/smpboot.c')
-rw-r--r-- | arch/x86/kernel/smpboot.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c new file mode 100644 index 0000000..bffe108 --- /dev/null +++ b/arch/x86/kernel/smpboot.c @@ -0,0 +1,53 @@ +#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 + |