From patchwork Fri May 12 21:07:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13239697 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 42F55C7EE24 for ; Fri, 12 May 2023 21:08:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240057AbjELVI1 (ORCPT ); Fri, 12 May 2023 17:08:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239762AbjELVHw (ORCPT ); Fri, 12 May 2023 17:07:52 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39D0DE733; Fri, 12 May 2023 14:07:22 -0700 (PDT) Message-ID: <20230512205256.206394064@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1683925640; 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=sV700lvJEg0dpnky36xy6IzX+5YcmbLPF3iuwfreLQI=; b=paQ53o7/mL5ElBtzALRvm5FWr+aqzidPhADEkGkNnFUgSdXdZKTpQ9LdM20zv3wNd69sIS it6M97+Fbbx8ktP1fteK/FRxSsUJ+d0bN0dEWXHrN+1EXE74+t5yfLHYlX4A2jlo5kaWpy u1Y4a1rKKqdKc7NvKZPW3+05W/WKM4dmC8NnWIBvmIiGSBT0dFtCcrPLjhVylwcQhwWEFh l3HKtTadZMnBQhRy9Lw4oQ4h0oFirsIvEgTyNYGnpZi6RiB0cbK/DRRrBfV3ithiX6HrKL M7rlozY1wPYf1JFhsOIHtY0UQp0uMjycyx8ukit8UWdY1BCjZKlup+pYCxy6HQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1683925640; 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=sV700lvJEg0dpnky36xy6IzX+5YcmbLPF3iuwfreLQI=; b=sb9Uqj+LJNN+k1afPutXlTsDK2EI5uKAFco5RBP+AD3FcfTjEj4fGPWwaSSh6It8iDbVO5 x1PNGDR7T4lyhTCA== 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)" , Ross Philipson Subject: [patch V4 14/37] x86/smpboot: Remove cpu_callin_mask References: <20230512203426.452963764@linutronix.de> MIME-Version: 1.0 Date: Fri, 12 May 2023 23:07:19 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Thomas Gleixner 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 Tested-by: Michael Kelley --- V4: Rename smp_callin() to ap_starting() - Peter Z. --- arch/x86/kernel/smpboot.c | 74 +++++++++------------------------------------- 1 file changed, 15 insertions(+), 59 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; @@ -161,38 +160,30 @@ static inline void smpboot_restore_warm_ } -/* - * Report back to the Boot Processor during boot time or to the caller processor - * during CPU online. - */ -static void smp_callin(void) +/* Run the next set of setup steps for the upcoming CPU */ +static void ap_starting(void) { - int cpuid; - - /* - * 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(); + int 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) + * If woken up by an INIT in an 82489DX configuration + * cpu_callout_mask guarantees the CPU does not reach this point + * before an INIT_deassert IPI reaches the local APIC, so it is now + * safe to touch the local APIC. + * + * Set up this CPU, first the APIC, which is probably redundant on + * most boards. */ apic_ap_setup(); - /* Save our processor parameters. */ + /* Save the processor parameters. */ smp_store_cpu_info(cpuid); /* * The topology information must be up to date before * notify_cpu_starting(). */ - set_cpu_sibling_map(raw_smp_processor_id()); + set_cpu_sibling_map(cpuid); ap_init_aperfmperf(); @@ -205,11 +196,6 @@ static void smp_callin(void) * state CPUHP_ONLINE. */ notify_cpu_starting(cpuid); - - /* - * Allow the master to continue. - */ - cpumask_set_cpu(cpuid, cpu_callin_mask); } static void ap_calibrate_delay(void) @@ -268,12 +254,7 @@ 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(); + ap_starting(); /* Check TSC synchronization with the control CPU. */ check_tsc_sync_target(); @@ -1109,7 +1090,7 @@ 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) { @@ -1124,20 +1105,7 @@ 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) @@ -1167,14 +1135,6 @@ 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: */ @@ -1211,7 +1171,6 @@ int native_cpu_up(unsigned int cpu, stru if (ret) goto out; - wait_cpu_callin(cpu); wait_cpu_online(cpu); out: @@ -1327,7 +1286,6 @@ 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) { @@ -1542,7 +1500,6 @@ 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); } @@ -1606,7 +1563,6 @@ 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);