From patchwork Mon Apr 29 11:22:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 10921683 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E83AF1515 for ; Mon, 29 Apr 2019 11:25:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D632B27C2D for ; Mon, 29 Apr 2019 11:25:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C75B5282E8; Mon, 29 Apr 2019 11:25:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 52E3E27C2D for ; Mon, 29 Apr 2019 11:25:09 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hL4NF-0007mM-4q; Mon, 29 Apr 2019 11:23:05 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hL4ND-0007mH-IA for xen-devel@lists.xenproject.org; Mon, 29 Apr 2019 11:23:03 +0000 X-Inumbo-ID: 25474eec-6a71-11e9-9fd0-0721d75f5957 Received: from prv1-mh.provo.novell.com (unknown [137.65.248.33]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 25474eec-6a71-11e9-9fd0-0721d75f5957; Mon, 29 Apr 2019 11:23:00 +0000 (UTC) Received: from INET-PRV1-MTA by prv1-mh.provo.novell.com with Novell_GroupWise; Mon, 29 Apr 2019 05:22:59 -0600 Message-Id: <5CC6DE8F0200007800229E9A@prv1-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 18.1.0 Date: Mon, 29 Apr 2019 05:22:55 -0600 From: "Jan Beulich" To: "xen-devel" References: <5CC6DD090200007800229E80@prv1-mh.provo.novell.com> In-Reply-To: <5CC6DD090200007800229E80@prv1-mh.provo.novell.com> Mime-Version: 1.0 Content-Disposition: inline Subject: [Xen-devel] [PATCH RFC 1/9] x86/IRQ: deal with move-in-progress state in fixup_irqs() X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Wei Liu , Roger Pau Monne Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP The flag being set may prevent affinity changes, as these often imply assignment of a new vector. When there's no possible destination left for the IRQ, the clearing of the flag needs to happen right from fixup_irqs(). Additionally _assign_irq_vector() needs to avoid setting the flag when there's no online CPU left in what gets put into ->arch.old_cpu_mask. The old vector can be released right away in this case. Also extend the log message about broken affinity to include the new affinity as well, allowing to notice issues with affinity changes not actually having taken place. Swap the if/else-if order there at the same time to reduce the amount of conditions checked. At the same time replace two open coded instances of the new helper function. Signed-off-by: Jan Beulich --- RFC: I've seen the new ASSERT() in irq_move_cleanup_interrupt() trigger. I'm pretty sure that this assertion triggering means something else is wrong, and has been even prior to this change (adding the assertion without any of the other changes here should be valid in my understanding). --- a/xen/arch/x86/irq.c +++ b/xen/arch/x86/irq.c @@ -242,6 +242,20 @@ void destroy_irq(unsigned int irq) xfree(action); } +static void release_old_vec(struct irq_desc *desc) +{ + unsigned int vector = desc->arch.old_vector; + + desc->arch.old_vector = IRQ_VECTOR_UNASSIGNED; + cpumask_clear(desc->arch.old_cpu_mask); + + if ( desc->arch.used_vectors ) + { + ASSERT(test_bit(vector, desc->arch.used_vectors)); + clear_bit(vector, desc->arch.used_vectors); + } +} + static void __clear_irq_vector(int irq) { int cpu, vector, old_vector; @@ -285,14 +299,7 @@ static void __clear_irq_vector(int irq) per_cpu(vector_irq, cpu)[old_vector] = ~irq; } - desc->arch.old_vector = IRQ_VECTOR_UNASSIGNED; - cpumask_clear(desc->arch.old_cpu_mask); - - if ( desc->arch.used_vectors ) - { - ASSERT(test_bit(old_vector, desc->arch.used_vectors)); - clear_bit(old_vector, desc->arch.used_vectors); - } + release_old_vec(desc); desc->arch.move_in_progress = 0; } @@ -517,12 +524,21 @@ next: /* Found one! */ current_vector = vector; current_offset = offset; - if (old_vector > 0) { - desc->arch.move_in_progress = 1; - cpumask_copy(desc->arch.old_cpu_mask, desc->arch.cpu_mask); + + if ( old_vector > 0 ) + { + cpumask_and(desc->arch.old_cpu_mask, desc->arch.cpu_mask, + &cpu_online_map); desc->arch.old_vector = desc->arch.vector; + if ( !cpumask_empty(desc->arch.old_cpu_mask) ) + desc->arch.move_in_progress = 1; + else + /* This can happen while offlining a CPU. */ + release_old_vec(desc); } + trace_irq_mask(TRC_HW_IRQ_ASSIGN_VECTOR, irq, vector, &tmp_mask); + for_each_cpu(new_cpu, &tmp_mask) per_cpu(vector_irq, new_cpu)[vector] = irq; desc->arch.vector = vector; @@ -691,14 +707,8 @@ void irq_move_cleanup_interrupt(struct c if ( desc->arch.move_cleanup_count == 0 ) { - desc->arch.old_vector = IRQ_VECTOR_UNASSIGNED; - cpumask_clear(desc->arch.old_cpu_mask); - - if ( desc->arch.used_vectors ) - { - ASSERT(test_bit(vector, desc->arch.used_vectors)); - clear_bit(vector, desc->arch.used_vectors); - } + ASSERT(vector == desc->arch.old_vector); + release_old_vec(desc); } unlock: spin_unlock(&desc->lock); @@ -2391,6 +2401,24 @@ void fixup_irqs(const cpumask_t *mask, b continue; } + /* + * In order for the affinity adjustment below to be successful, we + * need __assign_irq_vector() to succeed. This in particular means + * clearing desc->arch.move_in_progress if this would otherwise + * prevent the function from succeeding. Since there's no way for the + * flag to get cleared anymore when there's no possible destination + * left (the only possibility then would be the IRQs enabled window + * after this loop), there's then also no race with us doing it here. + * + * Therefore the logic here and there need to remain in sync. + */ + if ( desc->arch.move_in_progress && + !cpumask_intersects(mask, desc->arch.cpu_mask) ) + { + release_old_vec(desc); + desc->arch.move_in_progress = 0; + } + cpumask_and(&affinity, &affinity, mask); if ( cpumask_empty(&affinity) ) { @@ -2409,15 +2437,18 @@ void fixup_irqs(const cpumask_t *mask, b if ( desc->handler->enable ) desc->handler->enable(desc); + cpumask_copy(&affinity, desc->affinity); + spin_unlock(&desc->lock); if ( !verbose ) continue; - if ( break_affinity && set_affinity ) - printk("Broke affinity for irq %i\n", irq); - else if ( !set_affinity ) - printk("Cannot set affinity for irq %i\n", irq); + if ( !set_affinity ) + printk("Cannot set affinity for IRQ%u\n", irq); + else if ( break_affinity ) + printk("Broke affinity for IRQ%u, new: %*pb\n", + irq, nr_cpu_ids, &affinity); } /* That doesn't seem sufficient. Give it 1ms. */