From patchwork Thu May 4 19:02:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13231541 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B0936C7EE22 for ; Thu, 4 May 2023 19:02:46 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.529901.824958 (Exim 4.92) (envelope-from ) id 1pueDi-0000G2-Uy; Thu, 04 May 2023 19:02:26 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 529901.824958; Thu, 04 May 2023 19:02:26 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pueDi-0000BF-BD; Thu, 04 May 2023 19:02:26 +0000 Received: by outflank-mailman (input) for mailman id 529901; Thu, 04 May 2023 19:02:24 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pueDf-00042j-Vf for xen-devel@lists.xenproject.org; Thu, 04 May 2023 19:02:23 +0000 Received: from galois.linutronix.de (galois.linutronix.de [2a0a:51c0:0:12e:550::1]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 33e3e5b7-eaae-11ed-b226-6b7b168915f2; Thu, 04 May 2023 21:02:23 +0200 (CEST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 33e3e5b7-eaae-11ed-b226-6b7b168915f2 Message-ID: <20230504185937.145906075@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1683226943; 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: references:references; bh=lJLvACyWoTrqBZOps4v6XbP7wlJ3d4Q7defz4e+9Zb8=; b=M3KgFVyzFkR4ccZ70dYavQ5/yqmJzYsNUe2w4AYa1zmqPGpOGfvnO2dLe+bqfdSYVxHNmg UzxBYDkuh0vO9FnTUv0U0boU0E1jTAuFuEPxGvjM1vNFxZkY4+YKEIRoL7asL6MLh7WY2k YHroxEZc/MyAi6EghJhWG+wOe//5AznxGGSpRWucK1h/BnTyT75KngcAYt8WZjiMtq166b mZZvUfn/tKwnN+lYf/c6UiDK6atXikbDlaDBZ4sMT8u+PU/SPukxmYsr0YlXnC0aFBugr6 4bUgvijH50TXxyxKZ9qydiyNaQwVfzl3UXTSijqX2pY50ezKH3gbSbXO2Pf/Zg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1683226943; 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: references:references; bh=lJLvACyWoTrqBZOps4v6XbP7wlJ3d4Q7defz4e+9Zb8=; b=YUlyUuTQQYH6MyD4cTuFQt3gYiD8H4Dxlm3l2cVGkFebVjVj9D7krF98nosGppSH1sXEJ5 189JeF0cp5TwVnAA== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, David Woodhouse , Andrew Cooper , Brian Gerst , Arjan van de Veen , Paolo Bonzini , Paul McKenney , Tom Lendacky , Sean Christopherson , Oleksandr Natalenko , Paul Menzel , "Guilherme G. Piccoli" , Piotr Gorski , Usama Arif , Juergen Gross , Boris Ostrovsky , xen-devel@lists.xenproject.org, Russell King , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Guo Ren , linux-csky@vger.kernel.org, Thomas Bogendoerfer , linux-mips@vger.kernel.org, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Mark Rutland , Sabin Rapan , "Michael Kelley (LINUX)" Subject: [patch V2 15/38] x86/smpboot: Remove wait for cpu_online() References: <20230504185733.126511787@linutronix.de> MIME-Version: 1.0 Date: Thu, 4 May 2023 21:02:22 +0200 (CEST) From: Thomas Gleixner Now that the core code drops sparse_irq_lock after the idle thread synchronized, it's pointless to wait for the AP to mark itself online. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/smpboot.c | 26 ++------------------------ 1 file changed, 2 insertions(+), 24 deletions(-) --- --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -281,7 +281,6 @@ static void notrace start_secondary(void * half valid vector space. */ lock_vector_lock(); - /* Sync point with do_wait_cpu_online() */ set_cpu_online(smp_processor_id(), true); lapic_online(); unlock_vector_lock(); @@ -1110,20 +1109,6 @@ static int wait_cpu_initialized(unsigned return 0; } -/* - * Bringup step three: Wait for the target AP to reach set_cpu_online() in - * start_secondary(). - */ -static void wait_cpu_online(unsigned int cpu) -{ - /* - * Wait for the AP to mark itself online, so the core caller - * can drop sparse_irq_lock. - */ - while (!cpu_online(cpu)) - schedule(); -} - static int native_kick_ap(unsigned int cpu, struct task_struct *tidle) { int apicid = apic->cpu_present_to_apicid(cpu); @@ -1170,16 +1155,9 @@ int native_cpu_up(unsigned int cpu, stru int ret; ret = native_kick_ap(cpu, tidle); - if (ret) - goto out; - - ret = wait_cpu_initialized(cpu); - if (ret) - goto out; - - wait_cpu_online(cpu); + if (!ret) + ret = wait_cpu_initialized(cpu); -out: /* Cleanup possible dangling ends... */ if (x86_platform.legacy.warm_reset) smpboot_restore_warm_reset_vector();