From patchwork Mon May 8 19:43:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13234866 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 29BABC7EE24 for ; Mon, 8 May 2023 19:44:05 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.531761.827644 (Exim 4.92) (envelope-from ) id 1pw6m2-0000ir-Ip; Mon, 08 May 2023 19:43:54 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 531761.827644; Mon, 08 May 2023 19:43:54 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pw6m2-0000fj-3K; Mon, 08 May 2023 19:43:54 +0000 Received: by outflank-mailman (input) for mailman id 531761; Mon, 08 May 2023 19:43:52 +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 1pw6m0-0004GB-BN for xen-devel@lists.xenproject.org; Mon, 08 May 2023 19:43:52 +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 a8b44ada-edd8-11ed-b226-6b7b168915f2; Mon, 08 May 2023 21:43:51 +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: a8b44ada-edd8-11ed-b226-6b7b168915f2 Message-ID: <20230508185218.070008578@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1683575031; 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=DpwezFnftgf/NwnjaJYg18wbFoZRAK6UuAmlsWmBJR4=; b=i1TFZjgCtddkAakfxkISXw55XmrEJvUVPuQTFOFgS+oTTKVcNGhuqDExhfxWr3kSGXHZ9h Q+ujpZNUZEK3gioXPoyRZ+NzfuV4aL+sQupa7bIw509g00exAtAYyYGseE5+d40Ye/9iSn kyYz5rdl/ounEY4O9wO7ubw04Cyxxy6DTnoJB2oO2RietlbB/OitKYLkOQ8iHZAyHbfy1W bv+Q2OEIWcacTVCd+tTm0xqwTwSoZ8e7RLxQJArbSe8S99eF/7jfVItjSmrC275mG9pAip lscg+orwTig3a1iTNLS2jmVzL558VHIKrCz5q1WCRCIfLCf1r3Xa3vOeSE+ulQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1683575031; 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=DpwezFnftgf/NwnjaJYg18wbFoZRAK6UuAmlsWmBJR4=; b=p4MipbJWjxb6AbwUz07UF9If0ACyXBwES1Mx0lUk9qi+e9Q63raPnhjjqmne+YvfK1SUP6 eRiNkcZ4g3zeVxBg== 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 v3 15/36] x86/smpboot: Remove wait for cpu_online() References: <20230508181633.089804905@linutronix.de> MIME-Version: 1.0 Date: Mon, 8 May 2023 21:43:51 +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 Tested-by: Michael Kelley --- 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();