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=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 C15BBC433E6 for ; Mon, 1 Feb 2021 19:35:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86BA664E50 for ; Mon, 1 Feb 2021 19:35:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231610AbhBATft (ORCPT ); Mon, 1 Feb 2021 14:35:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229525AbhBATfr (ORCPT ); Mon, 1 Feb 2021 14:35:47 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 860C7C061573; Mon, 1 Feb 2021 11:35:07 -0800 (PST) Date: Mon, 1 Feb 2021 20:35:04 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1612208105; 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=H7q0ADVBv7wrASZe7+lbcKyA+aN2qy7UBOJmQRce20k=; b=bz0R4vyw46ywTkxpGU+9mHE5Y4ySzftT1jE9G1XqK1qHSiKhLeEEJQuOMF6uSOwTjUmuqm mVs+pSrV1miS4AjjaEsPuYE9E6h7jIlyqKJF26bbmybKWCjptNi0/uMOTDOskfAwFDbBvs 0zM9Ojy/BlnVkE3N13cHQPad9hn8wmWtTwbrPhnQzgVW/6Ax29q4u1m//yVPcodz6OODdx yymDFKG7P6/QIrqrc++pHhy1dhq/Q08iiZrXdgucSM4GM6rzogPgwuo9BG19oqXtLWkbyW ZV6Qh/bJl6ExBScHNzb8e14aSOsY/jfTq6srI+NVqzxj67T/qSS9LXgST/k0XQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1612208105; 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=H7q0ADVBv7wrASZe7+lbcKyA+aN2qy7UBOJmQRce20k=; b=t5vQ6hM45TikxRW//7L332EwTlPU7ZXxNihCYkLR9uH9EiwnMLOY+Cfoj0DmKEia5Dsnqj em8J1vo12VBxohAw== From: Sebastian Andrzej Siewior To: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jens Axboe , Thomas Gleixner , Peter Zijlstra , Ingo Molnar Subject: Re: [PATCH 1/3] smp: Process pending softirqs in flush_smp_call_function_from_idle() Message-ID: <20210201193504.oxceui2y52zsxqmv@linutronix.de> References: <20210123201027.3262800-1-bigeasy@linutronix.de> <20210123201027.3262800-2-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210123201027.3262800-2-bigeasy@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-01-23 21:10:25 [+0100], To linux-block@vger.kernel.org wrote: > send_call_function_single_ipi() may wake an idle CPU without sending an > IPI. The woken up CPU will process the SMP-functions in > flush_smp_call_function_from_idle(). Any raised softirq from within the > SMP-function call will not be processed. > Should the CPU have no tasks assigned, then it will go back to idle with > pending softirqs and the NOHZ will rightfully complain. > > Process pending softirqs on return from flush_smp_call_function_queue(). > > Fixes: b2a02fc43a1f4 ("smp: Optimize send_call_function_single_ipi()") > Reported-by: Jens Axboe > Signed-off-by: Sebastian Andrzej Siewior A gentle ping. This isn't just a requirement for the series: rps_trigger_softirq() is invoked from smp_call_function_single_async() and raises a softirq. Sebastian