[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 02/15] x86/IRQ: deal with move cleanup count state in fixup_irqs()
The cleanup IPI may get sent immediately before a CPU gets removed from the online map. In such a case the IPI would get handled on the CPU being offlined no earlier than in the interrupts disabled window after fixup_irqs()' main loop. This is too late, however, because a possible affinity change may incur the need for vector assignment, which will fail when the IRQ's move cleanup count is still non-zero. To fix this - record the set of CPUs the cleanup IPIs gets actually sent to alongside setting their count, - adjust the count in fixup_irqs(), accounting for all CPUs that the cleanup IPI was sent to, but that are no longer online, - bail early from the cleanup IPI handler when the CPU is no longer online, to prevent double accounting. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> --- a/xen/arch/x86/irq.c +++ b/xen/arch/x86/irq.c @@ -668,6 +668,9 @@ void irq_move_cleanup_interrupt(struct c ack_APIC_irq(); me = smp_processor_id(); + if ( !cpu_online(me) ) + return; + for ( vector = FIRST_DYNAMIC_VECTOR; vector <= LAST_HIPRIORITY_VECTOR; vector++) { @@ -727,11 +730,14 @@ unlock: static void send_cleanup_vector(struct irq_desc *desc) { - cpumask_t cleanup_mask; + cpumask_and(desc->arch.old_cpu_mask, desc->arch.old_cpu_mask, + &cpu_online_map); + desc->arch.move_cleanup_count = cpumask_weight(desc->arch.old_cpu_mask); - cpumask_and(&cleanup_mask, desc->arch.old_cpu_mask, &cpu_online_map); - desc->arch.move_cleanup_count = cpumask_weight(&cleanup_mask); - send_IPI_mask(&cleanup_mask, IRQ_MOVE_CLEANUP_VECTOR); + if ( desc->arch.move_cleanup_count ) + send_IPI_mask(desc->arch.old_cpu_mask, IRQ_MOVE_CLEANUP_VECTOR); + else + release_old_vec(desc); desc->arch.move_in_progress = 0; } @@ -2410,6 +2416,16 @@ void fixup_irqs(const cpumask_t *mask, b vector <= LAST_HIPRIORITY_VECTOR ) cpumask_and(desc->arch.cpu_mask, desc->arch.cpu_mask, mask); + if ( desc->arch.move_cleanup_count ) + { + /* The cleanup IPI may have got sent while we were still online. */ + cpumask_andnot(&affinity, desc->arch.old_cpu_mask, + &cpu_online_map); + desc->arch.move_cleanup_count -= cpumask_weight(&affinity); + if ( !desc->arch.move_cleanup_count ) + release_old_vec(desc); + } + cpumask_copy(&affinity, desc->affinity); if ( !desc->action || cpumask_subset(&affinity, mask) ) { _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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