diff options
Diffstat (limited to 'arch/x86/kernel/apic/vector.c')
| -rw-r--r-- | arch/x86/kernel/apic/vector.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c index 5e58da8efe77..14b21ca4483c 100644 --- a/arch/x86/kernel/apic/vector.c +++ b/arch/x86/kernel/apic/vector.c @@ -945,7 +945,37 @@ void irq_force_complete_move(struct irq_desc *desc) unlock: raw_spin_unlock(&vector_lock); } -#endif + +#ifdef CONFIG_HOTPLUG_CPU +/* + * Note, this is not accurate accounting, but at least good enough to + * prevent that the actual interrupt move will run out of vectors. + */ +int lapic_can_unplug_cpu(void) +{ + unsigned int rsvd, avl, tomove, cpu = smp_processor_id(); + int ret = 0; + + raw_spin_lock(&vector_lock); + tomove = irq_matrix_allocated(vector_matrix); + avl = irq_matrix_available(vector_matrix, true); + if (avl < tomove) { + pr_warn("CPU %u has %u vectors, %u available. Cannot disable CPU\n", + cpu, tomove, avl); + ret = -ENOSPC; + goto out; + } + rsvd = irq_matrix_reserved(vector_matrix); + if (avl < rsvd) { + pr_warn("Reserved vectors %u > available %u. IRQ request may fail\n", + rsvd, avl); + } +out: + raw_spin_unlock(&vector_lock); + return ret; +} +#endif /* HOTPLUG_CPU */ +#endif /* SMP */ static void __init print_APIC_field(int base) { |