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=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH 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 075C8C433F4 for ; Tue, 28 Aug 2018 17:57:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B27F820847 for ; Tue, 28 Aug 2018 17:57:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="f7pFSfkj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B27F820847 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=ti.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727865AbeH1Vtw (ORCPT ); Tue, 28 Aug 2018 17:49:52 -0400 Received: from fllv0016.ext.ti.com ([198.47.19.142]:36482 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727040AbeH1Vtv (ORCPT ); Tue, 28 Aug 2018 17:49:51 -0400 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id w7SHurXd098737; Tue, 28 Aug 2018 12:56:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1535479013; bh=ymoxweu15qYLc0XC1BN6g3wkvIP5PlSgfwg7BtU28BM=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=f7pFSfkjurrjLn1YELLnaxeFXPKn3Nv+yfbdv4YZnKv8aHKVBhKAWaHM0B/z69URz C75UhIBS4liuhxTJwtleNcWAs6e+we/rQgDCQgZWFIHLsiGsxC1FMjVwy0+eccI/6B 4zygvDRRQcoJ0+zaf4wuwDNgDGkfSM+dpcgcknDc= Received: from DFLE103.ent.ti.com (dfle103.ent.ti.com [10.64.6.24]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id w7SHurWM031428; Tue, 28 Aug 2018 12:56:53 -0500 Received: from DFLE111.ent.ti.com (10.64.6.32) by DFLE103.ent.ti.com (10.64.6.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1466.3; Tue, 28 Aug 2018 12:56:53 -0500 Received: from dlep33.itg.ti.com (157.170.170.75) by DFLE111.ent.ti.com (10.64.6.32) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1466.3 via Frontend Transport; Tue, 28 Aug 2018 12:56:53 -0500 Received: from [128.247.59.147] (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id w7SHur9p000680; Tue, 28 Aug 2018 12:56:53 -0500 Subject: Re: [PATCH] nohz: Fix missing tick reprog while interrupting inline timer softirq To: Frederic Weisbecker CC: Thomas Gleixner , Greg KH , LKML , Ingo Molnar , Anna-Maria Gleixner , , Tero Kristo References: <1533077570-9169-1-git-send-email-frederic@kernel.org> <8ecb9229-4c14-6967-0863-15b47cefd251@ti.com> <20180824061750.GA20523@kroah.com> <0d63c2bb-f75d-3f79-c19d-bb4ac9a00cd5@ti.com> <20180824184103.GD2730@lerouge> From: Grygorii Strashko Message-ID: <47d2416d-6359-1f48-311d-404fb5bfa3a8@ti.com> Date: Tue, 28 Aug 2018 12:56:53 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180824184103.GD2730@lerouge> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/24/2018 01:41 PM, Frederic Weisbecker wrote: > On Fri, Aug 24, 2018 at 11:10:44AM -0500, Grygorii Strashko wrote: >> Yes. i do not see local_softirq_pending messages any more >> >> But one question, just to clarify, after patch "nohz: Fix missing tick reprog while interrupting inline timer softirq" >> the tick_nohz_irq_exit() will be called few times in case of nested interrupts (min 2): >> gic_handle_irq >> |- irq_exit >> |- preempt_count_sub(HARDIRQ_OFFSET); >> |-__do_softirq >> >> |- gic_handle_irq() >> |- irq_exit() >> |- tick_irq_exit() >> if (!in_irq()) >> tick_nohz_irq_exit(); <-- [1] >> |- tick_irq_exit() >> if (!in_irq()) >> tick_nohz_irq_exit(); <-- [2] >> >> Is it correct? in 4.14 tick_nohz_irq_exit() is much more complex then in LKML now, >> and this is hot path. > > That's correct and it's indeed more costly in 4.14 as then the tick is going to be programmed > twice. > Sry, that disturbing you all, but what are the conclusion here for 4.14.y? - take Thomas's patch https://lore.kernel.org/patchwork/patch/969521/#1162900 - revert commit 2d898915ccf4838c04531c51a598469e921a5eb5 -- regards, -grygorii