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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66E9AC433F5 for ; Wed, 6 Oct 2021 11:19:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E2EC61373 for ; Wed, 6 Oct 2021 11:19:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238354AbhJFLVG (ORCPT ); Wed, 6 Oct 2021 07:21:06 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:57684 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238254AbhJFLUw (ORCPT ); Wed, 6 Oct 2021 07:20:52 -0400 From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1633519138; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1c+mt9Nk63OaX4OMSEWkc1KvDz8pF4SDlnSH3o4hh0Y=; b=RaDQSYUtH+/evYc5lEqyrGO2iIU53jnDrNaCeDs6Uwn2yejK/oXOiliOijqaru2pcmgaTQ MpLP9kdqlOXR3N6zYLET/+fdtDp5sbE++LRbFrSvQec0MWKLMBEc7hHrri71AvpDPy4Lg6 I91eKQyiQmrkdljT0HUcAZw4Fw+zNdH6KxHwpqTyKtNO/qTlr01t/2xzFNh7cyJsqT6BIK oqexzNKFupRxdPmXcOxmXBuoBw0ucrs2t0HUbgb69AtLko6QButM/Q9TJx044eRnU+e72t uibPfPE4ARircADikvO+yrvM1lWDS39/7WiLyrIZol41G6hnODt7q137Y0y3IQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1633519138; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1c+mt9Nk63OaX4OMSEWkc1KvDz8pF4SDlnSH3o4hh0Y=; b=Andb3sBOMuXbdUCfvsm48yQEUGfsBpP4dkPOtDlnVavFEueAOUUk+OdbHgG8RdLvfzdVI8 jbxuWpNgc0MsLkBQ== To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Thomas Gleixner , Sebastian Andrzej Siewior Subject: [PATCH v2 4/4] irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT Date: Wed, 6 Oct 2021 13:18:52 +0200 Message-Id: <20211006111852.1514359-5-bigeasy@linutronix.de> In-Reply-To: <20211006111852.1514359-1-bigeasy@linutronix.de> References: <20211006111852.1514359-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On PREEMPT_RT most items are processed as LAZY via softirq context. Avoid to spin-wait for them because irq_work_sync() could have higher priority and not allow the irq-work to be completed. Wait additionally for !IRQ_WORK_HARD_IRQ irq_work items on PREEMPT_RT. Signed-off-by: Sebastian Andrzej Siewior --- include/linux/irq_work.h | 5 +++++ kernel/irq_work.c | 6 ++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h index b48955e9c920e..8cd11a2232605 100644 --- a/include/linux/irq_work.h +++ b/include/linux/irq_work.h @@ -49,6 +49,11 @@ static inline bool irq_work_is_busy(struct irq_work *wor= k) return atomic_read(&work->node.a_flags) & IRQ_WORK_BUSY; } =20 +static inline bool irq_work_is_hard(struct irq_work *work) +{ + return atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ; +} + bool irq_work_queue(struct irq_work *work); bool irq_work_queue_on(struct irq_work *work, int cpu); =20 diff --git a/kernel/irq_work.c b/kernel/irq_work.c index daa5d12522faa..1833f9e23f224 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -214,7 +214,8 @@ void irq_work_single(void *arg) */ (void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY); =20 - if (!arch_irq_work_has_interrupt()) + if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) || + !arch_irq_work_has_interrupt()) rcuwait_wake_up(&work->irqwait); } =20 @@ -274,7 +275,8 @@ void irq_work_sync(struct irq_work *work) lockdep_assert_irqs_enabled(); might_sleep(); =20 - if (!arch_irq_work_has_interrupt()) { + if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) || + !arch_irq_work_has_interrupt()) { rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work), TASK_UNINTERRUPTIBLE); return; --=20 2.33.0