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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22CC4C433F5 for ; Tue, 19 Oct 2021 08:57:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E498460F9D for ; Tue, 19 Oct 2021 08:57:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234519AbhJSI7b (ORCPT ); Tue, 19 Oct 2021 04:59:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229930AbhJSI7a (ORCPT ); Tue, 19 Oct 2021 04:59:30 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E41ADC06161C; Tue, 19 Oct 2021 01:57:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=AePeC9nA2QI6mWSGX2S/0MTDQgzbvo7+Ukm6tKpOg5I=; b=HxaWCe95q0/3cE+7mOP3m/kEfH Y2+gVJAGq+7bjltDYOYzZMWn/PGR+LaIaVowHT1i1QYrAzPvaivHI3OuVqqRIbneHA5pZwIZB8QU6 focq0fcKVEX9QyPd/lsA1RnilWQa8iHlsZP2NB5Y/ujI49B8AVEnDdlikDhUCFwQJWI0cpyprJKFS ND+jYxE6mdi6iePTFjhHBHEMVoqxBEKVm/G1om5wfdXe8HrQpatjn8pIFA0sf+wsjlS6ROzQalk+E GP90/eIUMybnDPG6lOC7hRjKZX0M/9iw/1dEUVFoBDUy/MbYTkNZkZ/Ci7rJv1l3lmsSp6GrZELGu QewadT/A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mckvR-00AkJc-Kb; Tue, 19 Oct 2021 08:56:49 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 62AFF30024D; Tue, 19 Oct 2021 10:56:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3C1622C7C11E1; Tue, 19 Oct 2021 10:56:48 +0200 (CEST) Date: Tue, 19 Oct 2021 10:56:48 +0200 From: Peter Zijlstra To: Qian Cai Cc: gor@linux.ibm.com, jpoimboe@redhat.com, jikos@kernel.org, mbenes@suse.cz, pmladek@suse.com, mingo@kernel.org, linux-kernel@vger.kernel.org, joe.lawrence@redhat.com, fweisbec@gmail.com, tglx@linutronix.de, hca@linux.ibm.com, svens@linux.ibm.com, sumanthk@linux.ibm.com, live-patching@vger.kernel.org, paulmck@kernel.org, rostedt@goodmis.org, x86@kernel.org Subject: Re: [PATCH v2 04/11] sched: Simplify wake_up_*idle*() Message-ID: References: <20210929151723.162004989@infradead.org> <20210929152428.769328779@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Mon, Oct 18, 2021 at 11:47:32PM -0400, Qian Cai wrote: > Peter, any thoughts? I did confirm that reverting the commit fixed the issue. > > On 10/13/2021 10:32 AM, Qian Cai wrote: > > > > > > On 9/29/2021 11:17 AM, Peter Zijlstra wrote: > >> --- a/kernel/smp.c > >> +++ b/kernel/smp.c > >> @@ -1170,14 +1170,14 @@ void wake_up_all_idle_cpus(void) > >> { > >> int cpu; > >> > >> - preempt_disable(); > >> + cpus_read_lock(); > >> for_each_online_cpu(cpu) { > >> - if (cpu == smp_processor_id()) > >> + if (cpu == raw_smp_processor_id()) > >> continue; > >> > >> wake_up_if_idle(cpu); > >> } > >> - preempt_enable(); > >> + cpus_read_unlock(); Right, so yesterday I thought: YW2KGrvvv/vSA+97@hirez.programming.kicks-ass.net but today I might have another idea, lemme go prod at this a bit more.