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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 DD507C11F6F for ; Mon, 12 Jul 2021 08:08:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C691261947 for ; Mon, 12 Jul 2021 08:08:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233025AbhGLILc (ORCPT ); Mon, 12 Jul 2021 04:11:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346687AbhGLHbD (ORCPT ); Mon, 12 Jul 2021 03:31:03 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 332DEC005F24; Mon, 12 Jul 2021 00:25:44 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1626074738; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=icbIB7QTKPXqI/o8Y0H/OIL5w65Qd9ZrzW3+ozldd6k=; b=KIY5hoSrZleZkQd3Hr1NDdrVjxzCLM/ECRW+fWSNVeFZ6HqiY81KzsQV6Y2/NAwhLIMfO4 pFw+tsKXA4mQLwuu1N3BHyRE/fgIHsmizXnInfHdl11nLJay6Lxn8mmoPTYmwTC3RQyyz4 bfdEcJ7aRhCw6TIo99cnjO656sfcCBi3TSBURBmEKr1IZcfzKuYB3fEsP7OklV//9GbhMI UmPth8dCaBnPpW2rO3RaK3ZXcx0I2ArXu+Hi4RcCJzJwvX9EaKc6F9r9ess7ZLOkzi0IUA qAkOt8SeYYVF3CKtsYSjzLpS+GBn0/aCny4A1zBOxpUG0y9CgwfWVMq3fhHNPA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1626074738; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=icbIB7QTKPXqI/o8Y0H/OIL5w65Qd9ZrzW3+ozldd6k=; b=6SAQG5Jk/rtsvH7besLKDUpbdQKd3pcgfIe1n8Dl3FCahXf4nMtBqM5NuHtS2n4GIMFhIh +cYaVHiOn8aJtBDA== To: Linux Cc: mingo@redhat.com, hpa@zytor.com, dwmw@amazon.co.uk, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, songmuchun@bytedance.com, likunkun@bytedance.com, guancheng.rjk@alibaba-inc.com, duanxiongchun@bytedance.com, wenan.mao@linux.alibaba.com Subject: Re: [PATCH] use 64bit timer for hpet In-Reply-To: <2CC6F5DA-B186-4A06-92B4-B763386F0D0A@linux.alibaba.com> References: <1625213625-25745-1-git-send-email-zhaoyan.liao@linux.alibaba.com> <875yxmqw2s.ffs@nanos.tec.linutronix.de> <8A96C0F7-FBE4-4B23-8565-E814401BF927@linux.alibaba.com> <87o8bdoy11.ffs@nanos.tec.linutronix.de> <2CC6F5DA-B186-4A06-92B4-B763386F0D0A@linux.alibaba.com> Date: Mon, 12 Jul 2021 09:25:38 +0200 Message-ID: <875yxgngct.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Liao, On Mon, Jul 12 2021 at 12:52, Linux wrote: >> Sorry, keeping the softirq from running for 3 minutes is simply out of >> spec. If the sysadmin decides to do so, then he can keep the pieces. > > It is because the kernel thread is busy that the clocksource_watchdog > thread is not scheduled, not softirq. Which thread? The clocksource watchdog runs from a timer_list timer callback in softirq context. Even if the softirq is switched to the softirq thread then still my argument of starving that for 3 minutes still stands. This is _not_ a kernel problem. Overcommitment is a admin problem. Thanks, tglx