From nobody Fri Dec 19 18:53:05 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1F7D2633EA for ; Tue, 23 Jan 2024 13:11:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706015468; cv=none; b=ZyEjbfNs+WCHcolXZw0hLDX8y67WHnZIKk9K5OgSg4QJ7M1Hpc60Kp9qBSc4CZM1BQIeU+8XbNV1msQQS3RYGiqZcI5RbqAZ9Zh9NRqWait/seJdH34V3Hvfu/il2nclh1F7ukzuT3YJooQYu0+vuUWHrYEiM7yoTXkpiy6bGs0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706015468; c=relaxed/simple; bh=XBmMDfZ0gz2+VnrQJ9myM2OfczhLs81dGTuYtvW/uC0=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=nOwvAikGXpZZyrFifXCjDNA8csKuM5X1z6WKZ6KRR2fq4h/2AcHC2Qb17YviYPiEOiMXWEFA9UZPPUl/eLWtuj/V1mo4TRPPVrx6wIY/C14VD+U/lOU5Sy6DDk0qyGm8CgMNwXrqo7LIJKtAVTRN8kxhJfc0WaJRghHES++HoSM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=fem8r3jZ; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=4aAwjwRh; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="fem8r3jZ"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="4aAwjwRh" Message-ID: <20240118123649.060808881@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1706015465; 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=TTj/Kz9C0JKUULVztd5kGPjD2rrtKpaEznufq9qVeRw=; b=fem8r3jZdpIU2irArkJuEdoK6c00kWvNfcj98kNu8vDgQUFt3U7nMu+/Y0zTt+zw4ws6iF tRESMqKpDkbPJfA4epYGd8riY5T3S02RVGNlu0xuq4RaiWKYYv6YTegY1mX90sTzkf0Wgo TivkN3KkTlPrsCdig3yCuzq1IZKJJLcPN9VyMmmz05+FOPQavWQKxq+vKolqQTk4bl91l7 8mN0GzCO6GPVdRIHpNv19VuO2TDtkYf5LSAb7ho+Rsdq6Amn8i89y05u+hNzVs0j0allRh Tdy9+vtKRZ4tJUSoGpP3zTD0TKDxQaUVZmd088bkK9CORpi6qD4X9pDKRBu70w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1706015465; 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=TTj/Kz9C0JKUULVztd5kGPjD2rrtKpaEznufq9qVeRw=; b=4aAwjwRhigkMn8/qA7i7OnsVchgdSkTn7ICM+7IWFl42FYWdjcIKxnTcR02X5FTa0huoKN fKFBY6zHYcTKBfAg== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Tom Lendacky , Andrew Cooper , Arjan van de Ven , Huang Rui , Juergen Gross , Dimitri Sivanich , Sohil Mehta , K Prateek Nayak , Kan Liang , Zhang Rui , "Paul E. McKenney" , Feng Tang , Andy Shevchenko , Michael Kelley , "Peter Zijlstra (Intel)" Subject: [patch v2 09/30] x86/cpu/topology: Confine topology information References: <20240118123127.055361964@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Tue, 23 Jan 2024 14:11:04 +0100 (CET) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner Now that all external fiddling with num_processors and disabled_cpus is gone, move the last user prefill_possible_map() into the topology code too and remove the global visibility of these variables. Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/smp.h | 3 - arch/x86/kernel/apic/apic.c | 1=20 arch/x86/kernel/cpu/topology.c | 76 ++++++++++++++++++++++++++++++++++++= +++-- arch/x86/kernel/smpboot.c | 72 ------------------------------------= -- 4 files changed, 74 insertions(+), 78 deletions(-) --- --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -9,7 +9,6 @@ #include =20 extern int smp_num_siblings; -extern unsigned int num_processors; =20 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map); DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map); @@ -174,8 +173,6 @@ static inline struct cpumask *cpu_llc_sh } #endif /* CONFIG_SMP */ =20 -extern unsigned disabled_cpus; - #ifdef CONFIG_DEBUG_NMI_SELFTEST extern void nmi_selftest(void); #else --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2054,7 +2054,6 @@ void __init init_apic_mappings(void) pr_info("APIC: disable apic facility\n"); apic_disable(); } - num_processors =3D 1; } } =20 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -29,8 +29,8 @@ u32 cpuid_to_apicid[] __read_mostly =3D { */ static u32 disabled_cpu_apicid __ro_after_init =3D BAD_APICID; =20 -unsigned int num_processors; -unsigned disabled_cpus; +static unsigned int num_processors; +static unsigned int disabled_cpus; =20 /* * The number of allocated logical CPU IDs. Since logical CPU IDs are allo= cated @@ -174,6 +174,71 @@ static int generic_processor_info(int ap return cpu; } =20 +static int __initdata setup_possible_cpus =3D -1; + +/* + * cpu_possible_mask should be static, it cannot change as cpu's + * are onlined, or offlined. The reason is per-cpu data-structures + * are allocated by some modules at init time, and don't expect to + * do this dynamically on cpu arrival/departure. + * cpu_present_mask on the other hand can change dynamically. + * In case when cpu_hotplug is not compiled, then we resort to current + * behaviour, which is cpu_possible =3D=3D cpu_present. + * - Ashok Raj + * + * Three ways to find out the number of additional hotplug CPUs: + * - If the BIOS specified disabled CPUs in ACPI/mptables use that. + * - The user can overwrite it with possible_cpus=3DNUM + * - Otherwise don't reserve additional CPUs. + * We do this because additional CPUs waste a lot of memory. + * -AK + */ +__init void prefill_possible_map(void) +{ + int i, possible; + + i =3D setup_max_cpus ?: 1; + if (setup_possible_cpus =3D=3D -1) { + possible =3D num_processors; +#ifdef CONFIG_HOTPLUG_CPU + if (setup_max_cpus) + possible +=3D disabled_cpus; +#else + if (possible > i) + possible =3D i; +#endif + } else + possible =3D setup_possible_cpus; + + total_cpus =3D max_t(int, possible, num_processors + disabled_cpus); + + /* nr_cpu_ids could be reduced via nr_cpus=3D */ + if (possible > nr_cpu_ids) { + pr_warn("%d Processors exceeds NR_CPUS limit of %u\n", + possible, nr_cpu_ids); + possible =3D nr_cpu_ids; + } + +#ifdef CONFIG_HOTPLUG_CPU + if (!setup_max_cpus) +#endif + if (possible > i) { + pr_warn("%d Processors exceeds max_cpus limit of %u\n", + possible, setup_max_cpus); + possible =3D i; + } + + set_nr_cpu_ids(possible); + + pr_info("Allowing %d CPUs, %d hotplug CPUs\n", + possible, max_t(int, possible - num_processors, 0)); + + reset_cpu_possible_mask(); + + for (i =3D 0; i < possible; i++) + set_cpu_possible(i, true); +} + /** * topology_register_apic - Register an APIC in early topology maps * @apic_id: The APIC ID to set up @@ -251,6 +316,13 @@ void topology_hotunplug_apic(unsigned in } #endif =20 +static int __init _setup_possible_cpus(char *str) +{ + get_option(&str, &setup_possible_cpus); + return 0; +} +early_param("possible_cpus", _setup_possible_cpus); + static int __init apic_set_disabled_cpu_apicid(char *arg) { if (!arg || !get_option(&arg, &disabled_cpu_apicid)) --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1291,78 +1291,6 @@ void __init native_smp_cpus_done(unsigne cache_aps_init(); } =20 -static int __initdata setup_possible_cpus =3D -1; -static int __init _setup_possible_cpus(char *str) -{ - get_option(&str, &setup_possible_cpus); - return 0; -} -early_param("possible_cpus", _setup_possible_cpus); - - -/* - * cpu_possible_mask should be static, it cannot change as cpu's - * are onlined, or offlined. The reason is per-cpu data-structures - * are allocated by some modules at init time, and don't expect to - * do this dynamically on cpu arrival/departure. - * cpu_present_mask on the other hand can change dynamically. - * In case when cpu_hotplug is not compiled, then we resort to current - * behaviour, which is cpu_possible =3D=3D cpu_present. - * - Ashok Raj - * - * Three ways to find out the number of additional hotplug CPUs: - * - If the BIOS specified disabled CPUs in ACPI/mptables use that. - * - The user can overwrite it with possible_cpus=3DNUM - * - Otherwise don't reserve additional CPUs. - * We do this because additional CPUs waste a lot of memory. - * -AK - */ -__init void prefill_possible_map(void) -{ - int i, possible; - - i =3D setup_max_cpus ?: 1; - if (setup_possible_cpus =3D=3D -1) { - possible =3D num_processors; -#ifdef CONFIG_HOTPLUG_CPU - if (setup_max_cpus) - possible +=3D disabled_cpus; -#else - if (possible > i) - possible =3D i; -#endif - } else - possible =3D setup_possible_cpus; - - total_cpus =3D max_t(int, possible, num_processors + disabled_cpus); - - /* nr_cpu_ids could be reduced via nr_cpus=3D */ - if (possible > nr_cpu_ids) { - pr_warn("%d Processors exceeds NR_CPUS limit of %u\n", - possible, nr_cpu_ids); - possible =3D nr_cpu_ids; - } - -#ifdef CONFIG_HOTPLUG_CPU - if (!setup_max_cpus) -#endif - if (possible > i) { - pr_warn("%d Processors exceeds max_cpus limit of %u\n", - possible, setup_max_cpus); - possible =3D i; - } - - set_nr_cpu_ids(possible); - - pr_info("Allowing %d CPUs, %d hotplug CPUs\n", - possible, max_t(int, possible - num_processors, 0)); - - reset_cpu_possible_mask(); - - for (i =3D 0; i < possible; i++) - set_cpu_possible(i, true); -} - /* correctly size the local cpu masks */ void __init setup_cpu_local_masks(void) {