From patchwork Fri Apr 14 23:44:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13212046 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08104C77B77 for ; Fri, 14 Apr 2023 23:45:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230306AbjDNXpc (ORCPT ); Fri, 14 Apr 2023 19:45:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230250AbjDNXpC (ORCPT ); Fri, 14 Apr 2023 19:45:02 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E1B69ED5; Fri, 14 Apr 2023 16:44:36 -0700 (PDT) Message-ID: <20230414232310.010585365@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1681515875; 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=o+IIZolWdFzFoKPnCYeSD1bdkqJKKR73ExqiLPCERDI=; b=YtXMog5VLahh+j7fmWogAvr6ObdCeMs2/pQmIXREKblleGoCtvJL4rCNiqdvWzbyjDcTRQ uiN2/aQVEAqhEyWPSPIkKx0AVkXmtnjjoHfjwT3/yh44khK5MSa6L7h2bJz7b22ZDlJ6sh 00pAwnPCUJWCsn2Ejc57QMUUvq4xsRjx3LwBphTuReLzL6PmYvBpWBQh7nPpyk6UmRKfhO 2Eee0WLf6JgST16c76h3RPniWFIj95CGMwloYJMAwCCsO+gfqOq1rnGnjyKNvGqHT1gYGv P1F3HkYh07cMCdG7gc3D1VPgXDTVfI3a8otMhGht4nwU8AdufkquSsBkf+sOZA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1681515875; 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=o+IIZolWdFzFoKPnCYeSD1bdkqJKKR73ExqiLPCERDI=; b=/GA3IGAqyXeZ0ie5H89dtUrqgSL/9oSjEmZXWUtsSX1UpgcGxjRjqmWWhXVPw2ws/g8YlI DVurnNfTpyXvJvDg== 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 , David Woodhouse , 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 Subject: [patch 13/37] x86/smpboot: Remove cpu_callin_mask References: <20230414225551.858160935@linutronix.de> MIME-Version: 1.0 Date: Sat, 15 Apr 2023 01:44:34 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Now that TSC synchronization is SMP function call based there is no reason to wait for the AP to be set in smp_callin_mask. The control CPU waits for the AP to set itself in the online mask anyway. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/smpboot.c | 61 +++++++--------------------------------------- 1 file changed, 10 insertions(+), 51 deletions(-) --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -104,7 +104,6 @@ EXPORT_PER_CPU_SYMBOL(cpu_info); /* All of these masks are initialized in setup_cpu_local_masks() */ static cpumask_var_t cpu_initialized_mask; static cpumask_var_t cpu_callout_mask; -static cpumask_var_t cpu_callin_mask; /* Representing CPUs for which sibling maps can be computed */ static cpumask_var_t cpu_sibling_setup_mask; @@ -167,21 +166,16 @@ static inline void smpboot_restore_warm_ */ static void smp_callin(void) { - int cpuid; + int cpuid = smp_processor_id(); /* * If waken up by an INIT in an 82489DX configuration - * cpu_callout_mask guarantees we don't get here before - * an INIT_deassert IPI reaches our local APIC, so it is - * now safe to touch our local APIC. - */ - cpuid = smp_processor_id(); - - /* - * the boot CPU has finished the init stage and is spinning - * on callin_map until we finish. We are free to set up this - * CPU, first the APIC. (this is probably redundant on most - * boards) + * cpu_callout_mask guarantees we don't get here before an + * INIT_deassert IPI reaches our local APIC, so it is now safe to + * touch our local APIC. + * + * Set up this CPU, first the APIC, which is probably redundant on + * most boards. */ apic_ap_setup(); @@ -192,7 +186,7 @@ static void smp_callin(void) * The topology information must be up to date before * calibrate_delay() and notify_cpu_starting(). */ - set_cpu_sibling_map(raw_smp_processor_id()); + set_cpu_sibling_map(cpuid); ap_init_aperfmperf(); @@ -205,11 +199,6 @@ static void smp_callin(void) * state (CPUHP_ONLINE in the case of serial bringup). */ notify_cpu_starting(cpuid); - - /* - * Allow the master to continue. - */ - cpumask_set_cpu(cpuid, cpu_callin_mask); } static void ap_calibrate_delay(void) @@ -268,11 +257,6 @@ static void notrace start_secondary(void rcu_cpu_starting(raw_smp_processor_id()); x86_cpuinit.early_percpu_clock_init(); - /* - * Sync point with wait_cpu_callin(). The AP doesn't wait here - * but just sets the bit to let the controlling CPU (BSP) know that - * it's got this far. - */ smp_callin(); /* Otherwise gcc will move up smp_processor_id() before cpu_init() */ @@ -1112,7 +1096,7 @@ static int wait_cpu_cpumask(unsigned int * and thus wait_for_master_cpu(), then set cpu_callout_mask to allow it * to proceed. The AP will then proceed past setting its 'callin' bit * and end up waiting in check_tsc_sync_target() until we reach - * do_wait_cpu_online() to tend to it. + * wait_cpu_online() to tend to it. */ static int wait_cpu_initialized(unsigned int cpu) { @@ -1127,20 +1111,7 @@ static int wait_cpu_initialized(unsigned } /* - * Bringup step three: Wait for the target AP to reach smp_callin(). - * The AP is not waiting for us here so we don't need to parallelise - * this step. Not entirely clear why we care about this, since we just - * proceed directly to TSC synchronization which is the next sync - * point with the AP anyway. - */ -static void wait_cpu_callin(unsigned int cpu) -{ - while (!cpumask_test_cpu(cpu, cpu_callin_mask)) - schedule(); -} - -/* - * Bringup step four: Wait for the target AP to reach set_cpu_online() in + * Bringup step three: Wait for the target AP to reach set_cpu_online() in * start_secondary(). */ static void wait_cpu_online(unsigned int cpu) @@ -1170,14 +1141,6 @@ static int native_kick_ap(unsigned int c } /* - * Already booted CPU? - */ - if (cpumask_test_cpu(cpu, cpu_callin_mask)) { - pr_debug("do_boot_cpu %d Already started\n", cpu); - return -ENOSYS; - } - - /* * Save current MTRR state in case it was changed since early boot * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync: */ @@ -1214,7 +1177,6 @@ int native_cpu_up(unsigned int cpu, stru if (ret) goto out; - wait_cpu_callin(cpu); wait_cpu_online(cpu); out: @@ -1330,7 +1292,6 @@ void __init smp_prepare_cpus_common(void * Setup boot CPU information */ smp_store_boot_cpu_info(); /* Final full version of the data */ - cpumask_copy(cpu_callin_mask, cpumask_of(0)); mb(); for_each_possible_cpu(i) { @@ -1545,7 +1506,6 @@ early_param("possible_cpus", _setup_poss void __init setup_cpu_local_masks(void) { alloc_bootmem_cpumask_var(&cpu_initialized_mask); - alloc_bootmem_cpumask_var(&cpu_callin_mask); alloc_bootmem_cpumask_var(&cpu_callout_mask); alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask); } @@ -1609,7 +1569,6 @@ static void remove_cpu_from_maps(int cpu { set_cpu_online(cpu, false); cpumask_clear_cpu(cpu, cpu_callout_mask); - cpumask_clear_cpu(cpu, cpu_callin_mask); /* was set by cpu_init() */ cpumask_clear_cpu(cpu, cpu_initialized_mask); numa_remove_cpu(cpu);