From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39161C10F0E for ; Tue, 9 Apr 2019 09:34:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 086132084C for ; Tue, 9 Apr 2019 09:34:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oyXftwAE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726937AbfDIJeR (ORCPT ); Tue, 9 Apr 2019 05:34:17 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:39673 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726133AbfDIJeR (ORCPT ); Tue, 9 Apr 2019 05:34:17 -0400 Received: by mail-pg1-f193.google.com with SMTP id k3so8977710pga.6 for ; Tue, 09 Apr 2019 02:34:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=2N+5jiEm0s/U2LTS+8nQ21jut0Nu3Hq3t6TQBxBjLPk=; b=oyXftwAEU3sjeUXHhhr9SX8UD1Bd0orzHbkk7RSE0KuX+sEe+PVHpzUTHJVaRbxSwe 3tinPmMWZbyIKXF0O8rbRK7ar5H0W0aI4adDC77hQliius64qASwX7Yp50OSrLnSMUrH umfL1/9h4ecEi33OB9oc40+cXLLOMQpHFXWKcclqrVbj/1iRHw9Ib2EEEAQm/1wQQpVL R3XKG3ICRhu9DkZ704JJ0uCA85VX3x8jYzSPm6m5Z0gwQ/bKNpMZnXKc2RQgL2fJQQ+c GLOdg+IA9y3XKuGt4jnsX0ii/RM9hY4SXXlFnThrPN1uTtl63fI7OL//zrRhw5clhdpA T0XQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=2N+5jiEm0s/U2LTS+8nQ21jut0Nu3Hq3t6TQBxBjLPk=; b=FR82Y8bR28cEYSMXL5vN7dZRRgJj3BwzjVPfkkeE2qz2UVHlUz5HuuK2LteiYLjYNg f2tE9w9QTg2yEaTWYMcV8IKVNkie7nGv3IcrD2ARgkJ2UiLEdvYV2k/DLidzoT+x1bOv 6111mC8ZrW5Qr/IOw1y1ECSItHB4Eyps0wb/p7FuS4XPxyasArWRF4kDNUJf8OBOetGF tehqsxFDQipT4nZg83XVDLJkA5Pqtt5Zwf1mgEvm+jyUJGUQmQnP/CQvoM92rhNbG6WX VOhCqw8Hotou+uyu9XjSzhpeUf2cSMb1KvN52E+Tm5br5Y2KEqBqm4WD1BmQ6JkLxikz vo4g== X-Gm-Message-State: APjAAAV08j5yf9np3SKVatqCxVpreE8l4F3cVKP7jY4nr37OJU7i/uDa u0HKsXcbRP25VGVvxUI0CZM= X-Google-Smtp-Source: APXvYqzhO65Xzo4IO+b31eRGM8g8TnjxyHsIgkEh1iyBS+1c9jr2oKhgJ5uVWfRyXg+oVeHqN5YwYg== X-Received: by 2002:a65:64cf:: with SMTP id t15mr32643244pgv.322.1554802456213; Tue, 09 Apr 2019 02:34:16 -0700 (PDT) Received: from bobo.local0.net ([58.84.79.14]) by smtp.gmail.com with ESMTPSA id b63sm88892686pfj.54.2019.04.09.02.34.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Apr 2019 02:34:15 -0700 (PDT) From: Nicholas Piggin To: Thomas Gleixner Cc: Nicholas Piggin , linux-kernel@vger.kernel.org, =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Suraj Jitindar Singh , Paul Mackerras , Sebastian Andrzej Siewior , Steven Rostedt , Peter Zijlstra , Frederic Weisbecker Subject: [PATCH] irq_work: Do not raise an IPI when queueing work on the local CPU Date: Tue, 9 Apr 2019 19:34:03 +1000 Message-Id: <20190409093403.20994-1-npiggin@gmail.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The QEMU powerpc/pseries machine model was not expecting a self-IPI, and it may be a bit surprising thing to do, so have irq_work_queue_on do local queueing when target is the current CPU. Reported-by: Sebastian Andrzej Siewior Tested-by: Sebastian Andrzej Siewior Suggested-by: Steven Rostedt Acked-by: Peter Zijlstra (Intel) Reviewed-by: Frederic Weisbecker Signed-off-by: Nicholas Piggin --- kernel/irq_work.c | 78 ++++++++++++++++++++++++++--------------------- 1 file changed, 43 insertions(+), 35 deletions(-) diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 6b7cdf17ccf8..d2cdf2367c16 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -56,61 +56,69 @@ void __weak arch_irq_work_raise(void) */ } -/* - * Enqueue the irq_work @work on @cpu unless it's already pending - * somewhere. - * - * Can be re-enqueued while the callback is still in progress. - */ -bool irq_work_queue_on(struct irq_work *work, int cpu) +/* Enqueue on current CPU, work must already be claimed and preempt disabled */ +static void __irq_work_queue_local(struct irq_work *work) { - /* All work should have been flushed before going offline */ - WARN_ON_ONCE(cpu_is_offline(cpu)); - -#ifdef CONFIG_SMP - - /* Arch remote IPI send/receive backend aren't NMI safe */ - WARN_ON_ONCE(in_nmi()); + /* If the work is "lazy", handle it from next tick if any */ + if (work->flags & IRQ_WORK_LAZY) { + if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) && + tick_nohz_tick_stopped()) + arch_irq_work_raise(); + } else { + if (llist_add(&work->llnode, this_cpu_ptr(&raised_list))) + arch_irq_work_raise(); + } +} +/* Enqueue the irq work @work on the current CPU */ +bool irq_work_queue(struct irq_work *work) +{ /* Only queue if not already pending */ if (!irq_work_claim(work)) return false; - if (llist_add(&work->llnode, &per_cpu(raised_list, cpu))) - arch_send_call_function_single_ipi(cpu); - -#else /* #ifdef CONFIG_SMP */ - irq_work_queue(work); -#endif /* #else #ifdef CONFIG_SMP */ + /* Queue the entry and raise the IPI if needed. */ + preempt_disable(); + __irq_work_queue_local(work); + preempt_enable(); return true; } +EXPORT_SYMBOL_GPL(irq_work_queue); -/* Enqueue the irq work @work on the current CPU */ -bool irq_work_queue(struct irq_work *work) +/* + * Enqueue the irq_work @work on @cpu unless it's already pending + * somewhere. + * + * Can be re-enqueued while the callback is still in progress. + */ +bool irq_work_queue_on(struct irq_work *work, int cpu) { +#ifndef CONFIG_SMP + return irq_work_queue(work); + +#else /* #ifndef CONFIG_SMP */ + /* All work should have been flushed before going offline */ + WARN_ON_ONCE(cpu_is_offline(cpu)); + /* Only queue if not already pending */ if (!irq_work_claim(work)) return false; - /* Queue the entry and raise the IPI if needed. */ preempt_disable(); - - /* If the work is "lazy", handle it from next tick if any */ - if (work->flags & IRQ_WORK_LAZY) { - if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) && - tick_nohz_tick_stopped()) - arch_irq_work_raise(); - } else { - if (llist_add(&work->llnode, this_cpu_ptr(&raised_list))) - arch_irq_work_raise(); - } - + if (cpu != smp_processor_id()) { + /* Arch remote IPI send/receive backend aren't NMI safe */ + WARN_ON_ONCE(in_nmi()); + if (llist_add(&work->llnode, &per_cpu(raised_list, cpu))) + arch_send_call_function_single_ipi(cpu); + } else + __irq_work_queue_local(work); preempt_enable(); return true; +#endif /* #else #ifndef CONFIG_SMP */ } -EXPORT_SYMBOL_GPL(irq_work_queue); + bool irq_work_needs_cpu(void) { -- 2.20.1