diff options
| -rw-r--r-- | arch/x86/include/asm/apic.h | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/irq.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/apic/vector.c | 32 | ||||
| -rw-r--r-- | arch/x86/kernel/irq.c | 99 | ||||
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 2 |
5 files changed, 33 insertions, 105 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 7a8651921ed5..a9e57f08bfa6 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -386,6 +386,7 @@ extern struct apic *__apicdrivers[], *__apicdrivers_end[]; */ #ifdef CONFIG_SMP extern int wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip); +extern int lapic_can_unplug_cpu(void); #endif #ifdef CONFIG_X86_LOCAL_APIC diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h index 9958ceea2fa3..1002a3e8fccc 100644 --- a/arch/x86/include/asm/irq.h +++ b/arch/x86/include/asm/irq.h @@ -25,11 +25,7 @@ extern void irq_ctx_init(int cpu); struct irq_desc; -#ifdef CONFIG_HOTPLUG_CPU -#include <linux/cpumask.h> -extern int check_irq_vectors_for_cpu_disable(void); extern void fixup_irqs(void); -#endif #ifdef CONFIG_HAVE_KVM extern void kvm_set_posted_intr_wakeup_handler(void (*handler)(void)); 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) { diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 188990c3a514..49cfd9fe7589 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -333,105 +333,6 @@ __visible void smp_kvm_posted_intr_nested_ipi(struct pt_regs *regs) #ifdef CONFIG_HOTPLUG_CPU - -/* These two declarations are only used in check_irq_vectors_for_cpu_disable() - * below, which is protected by stop_machine(). Putting them on the stack - * results in a stack frame overflow. Dynamically allocating could result in a - * failure so declare these two cpumasks as global. - */ -static struct cpumask affinity_new, online_new; - -/* - * This cpu is going to be removed and its vectors migrated to the remaining - * online cpus. Check to see if there are enough vectors in the remaining cpus. - * This function is protected by stop_machine(). - */ -int check_irq_vectors_for_cpu_disable(void) -{ - unsigned int this_cpu, vector, this_count, count; - struct irq_desc *desc; - struct irq_data *data; - int cpu; - - this_cpu = smp_processor_id(); - cpumask_copy(&online_new, cpu_online_mask); - cpumask_clear_cpu(this_cpu, &online_new); - - this_count = 0; - for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { - desc = __this_cpu_read(vector_irq[vector]); - if (IS_ERR_OR_NULL(desc)) - continue; - /* - * Protect against concurrent action removal, affinity - * changes etc. - */ - raw_spin_lock(&desc->lock); - data = irq_desc_get_irq_data(desc); - cpumask_copy(&affinity_new, - irq_data_get_affinity_mask(data)); - cpumask_clear_cpu(this_cpu, &affinity_new); - - /* Do not count inactive or per-cpu irqs. */ - if (!irq_desc_has_action(desc) || irqd_is_per_cpu(data)) { - raw_spin_unlock(&desc->lock); - continue; - } - - raw_spin_unlock(&desc->lock); - /* - * A single irq may be mapped to multiple cpu's - * vector_irq[] (for example IOAPIC cluster mode). In - * this case we have two possibilities: - * - * 1) the resulting affinity mask is empty; that is - * this the down'd cpu is the last cpu in the irq's - * affinity mask, or - * - * 2) the resulting affinity mask is no longer a - * subset of the online cpus but the affinity mask is - * not zero; that is the down'd cpu is the last online - * cpu in a user set affinity mask. - */ - if (cpumask_empty(&affinity_new) || - !cpumask_subset(&affinity_new, &online_new)) - this_count++; - } - /* No need to check any further. */ - if (!this_count) - return 0; - - count = 0; - for_each_online_cpu(cpu) { - if (cpu == this_cpu) - continue; - /* - * We scan from FIRST_EXTERNAL_VECTOR to first system - * vector. If the vector is marked in the used vectors - * bitmap or an irq is assigned to it, we don't count - * it as available. - * - * As this is an inaccurate snapshot anyway, we can do - * this w/o holding vector_lock. - */ - for (vector = FIRST_EXTERNAL_VECTOR; - vector < FIRST_SYSTEM_VECTOR; vector++) { - if (!test_bit(vector, system_vectors) && - IS_ERR_OR_NULL(per_cpu(vector_irq, cpu)[vector])) { - if (++count == this_count) - return 0; - } - } - } - - if (count < this_count) { - pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n", - this_cpu, this_count, count); - return -ERANGE; - } - return 0; -} - /* A cpu has been removed from cpu_online_mask. Reset irq affinities. */ void fixup_irqs(void) { diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 86739f04701b..92aadfa30d61 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1525,7 +1525,7 @@ int native_cpu_disable(void) { int ret; - ret = check_irq_vectors_for_cpu_disable(); + ret = lapic_can_unplug_cpu(); if (ret) return ret; |