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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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54 lines
1.5 KiB
C
54 lines
1.5 KiB
C
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#include <linux/init.h>
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#include <linux/smp.h>
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#ifdef CONFIG_HOTPLUG_CPU
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int additional_cpus __initdata = -1;
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static __init int setup_additional_cpus(char *s)
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{
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return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
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}
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early_param("additional_cpus", setup_additional_cpus);
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/*
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* cpu_possible_map should be static, it cannot change as cpu's
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* are onlined, or offlined. The reason is per-cpu data-structures
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* are allocated by some modules at init time, and dont expect to
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* do this dynamically on cpu arrival/departure.
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* cpu_present_map on the other hand can change dynamically.
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* In case when cpu_hotplug is not compiled, then we resort to current
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* behaviour, which is cpu_possible == cpu_present.
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* - Ashok Raj
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*
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* Three ways to find out the number of additional hotplug CPUs:
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* - If the BIOS specified disabled CPUs in ACPI/mptables use that.
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* - The user can overwrite it with additional_cpus=NUM
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* - Otherwise don't reserve additional CPUs.
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* We do this because additional CPUs waste a lot of memory.
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* -AK
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*/
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__init void prefill_possible_map(void)
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{
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int i;
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int possible;
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if (additional_cpus == -1) {
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if (disabled_cpus > 0)
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additional_cpus = disabled_cpus;
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else
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additional_cpus = 0;
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}
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possible = num_processors + additional_cpus;
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if (possible > NR_CPUS)
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possible = NR_CPUS;
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printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
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possible, max_t(int, possible - num_processors, 0));
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for (i = 0; i < possible; i++)
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cpu_set(i, cpu_possible_map);
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}
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#endif
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