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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 36EA5C64E7A for ; Wed, 25 Nov 2020 02:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA47620BED for ; Wed, 25 Nov 2020 02:16:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="RdwpOJix" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726603AbgKYCQB (ORCPT ); Tue, 24 Nov 2020 21:16:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:38162 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725287AbgKYCQA (ORCPT ); Tue, 24 Nov 2020 21:16:00 -0500 Received: from localhost.localdomain (unknown [94.238.200.242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 938DB20BED; Wed, 25 Nov 2020 02:15:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606270560; bh=SpjewY+zCUd4+dIAcXesrctaRe/IkPPUnJz7GEMao2c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RdwpOJixZ7e0vyG7uFfu1Wbbhqq9tOMFxt8fKy967bqDJFh8yY5UBwmrdPB7zdQp8 qeRAYkLhw+ycCMmZz79SepIH0W4xaOcvS31cDjtaAWDC/02rWDX2Su0jHv2ysolwV5 Tsb4QlR1JhKQOg0mQ5cBmv25RAOSUdA6nYa1kroI= From: Frederic Weisbecker To: Thomas Gleixner Cc: LKML , Frederic Weisbecker , Tony Luck , Peter Zijlstra , Vasily Gorbik , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Christian Borntraeger , Fenghua Yu , Heiko Carstens Subject: [RFC PATCH 4/4] irq: Call tick_irq_enter() inside HARDIRQ_OFFSET Date: Wed, 25 Nov 2020 03:15:42 +0100 Message-Id: <20201125021542.30237-5-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201125021542.30237-1-frederic@kernel.org> References: <20201125021542.30237-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that account_irq_enter_time() is called after HARDIRQ_OFFSET has been incremented, there is nothing left that prevents us from also moving tick_irq_enter() after HARDIRQ_OFFSET is incremented. The desired outcome is to remove the nasty hack that prevents softirqs from being raised through ksoftirqd instead of the hardirq bottom half. Also tick_irq_enter() then becomes appropriately covered by lockdep. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Tony Luck Cc: Fenghua Yu Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger --- kernel/softirq.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/kernel/softirq.c b/kernel/softirq.c index 24254c41bb7c..447ee4d6fe4d 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -377,16 +377,12 @@ asmlinkage __visible void __softirq_entry __do_softirq(void) */ void irq_enter_rcu(void) { - if (is_idle_task(current) && !in_interrupt()) { - /* - * Prevent raise_softirq from needlessly waking up ksoftirqd - * here, as softirq will be serviced on return from interrupt. - */ - local_bh_disable(); + __irq_enter_raw(); + + if (is_idle_task(current) && (irq_count() == HARDIRQ_OFFSET)) tick_irq_enter(); - _local_bh_enable(); - } - __irq_enter(); + + account_irq_enter_time(current); } /** -- 2.25.1