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 B2F2DC433ED for ; Wed, 14 Apr 2021 07:13:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8ABE1613A9 for ; Wed, 14 Apr 2021 07:13:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349593AbhDNHN4 (ORCPT ); Wed, 14 Apr 2021 03:13:56 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:51310 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349581AbhDNHNq (ORCPT ); Wed, 14 Apr 2021 03:13:46 -0400 Date: Wed, 14 Apr 2021 09:13:22 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1618384404; 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=s1a8CshZw26m5BPo40fPgY70peR7b/oBo1WgNZJ84PU=; b=tfoPDrMz+bDx6GEZ18qfSmD32hyCOd50f121Wj+M1N+AESll+NPKTJF8jLv2RPCaxXKegg Qmj85Ehh8bOAwsEnwJ/iz6jAD4LdoA1J7qdCu3em3suVAWV7DKySDCGmpEHnue7IOOwTLp IZyNN0oGroPATeyUUzKracVt5rWp0GI+K4tL8eYArpqV0i5yX1tCXJrSwM6R31I7wRMHF0 Cjqc5Jb6lIsy4oz9K6U5ScTtWg8lDKO2/XV2zpOBlE7V/OtBEkxLHjWFTnsC6yS6F2E9T9 5MJNV8r1iC5vyO5erEIAeOt+AGF1L/PnXHV2seu3P/lvdWI8nVCWcro6LnDuLQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1618384404; 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=s1a8CshZw26m5BPo40fPgY70peR7b/oBo1WgNZJ84PU=; b=/ji24/zUdBjSgpPBk3m4wRAgZ/rOTRnNiDW44YXS/9ETjOx6+6CyfN+OXZI6NdX9IRqo32 kaapHP+y/CBhTlBg== From: Sebastian Andrzej Siewior To: "Paul E. McKenney" Cc: Thomas Gleixner , "tip-bot2 for Paul E. McKenney" , linux-tip-commits@vger.kernel.org, Uladzislau Rezki , Peter Zijlstra , Frederic Weisbecker , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [tip: core/rcu] softirq: Don't try waking ksoftirqd before it has been spawned Message-ID: <20210414071322.nz64kow4sp4nwzmy@linutronix.de> References: <161814860838.29796.15260901429057690999.tip-bot2@tip-bot2> <87czuz1tbc.ffs@nanos.tec.linutronix.de> <20210412183645.GF4510@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210412183645.GF4510@paulmck-ThinkPad-P17-Gen-1> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-04-12 11:36:45 [-0700], Paul E. McKenney wrote: > > Color me confused. I did not follow the discussion around this > > completely, but wasn't it agreed on that this rcu torture muck can wait > > until the threads are brought up? > > Yes, we can cause rcutorture to wait. But in this case, rcutorture > is just the messenger, and making it wait would simply be ignoring > the message. The message is that someone could invoke any number of > things that wait on a softirq handler's invocation during the interval > before ksoftirqd has been spawned. My memory on this is that the only user, that required this early behaviour, was kprobe which was recently changed to not need it anymore. Which makes the test as the only user that remains. Therefore I thought that this test will be moved to later position (when ksoftirqd is up and running) and that there is no more requirement for RCU to be completely up that early in the boot process. Did I miss anything? > > Thanx, Paul Sebastian