From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Tom Lendacky <thomas.lendacky@amd.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Arjan van de Ven <arjan@linux.intel.com>,
Huang Rui <ray.huang@amd.com>, Juergen Gross <jgross@suse.com>,
Dimitri Sivanich <dimitri.sivanich@hpe.com>,
Sohil Mehta <sohil.mehta@intel.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Kan Liang <kan.liang@linux.intel.com>,
Zhang Rui <rui.zhang@intel.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Feng Tang <feng.tang@intel.com>,
Andy Shevchenko <andy@infradead.org>,
Michael Kelley <mhklinux@outlook.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [patch 23/30] x86/cpu/topology: Simplify cpu_mark_primary_thread()
Date: Tue, 13 Feb 2024 22:06:06 +0100 (CET) [thread overview]
Message-ID: <20240213210252.791176581@linutronix.de> (raw)
In-Reply-To: 20240213205415.307029033@linutronix.de
From: Thomas Gleixner <tglx@linutronix.de>
No point in creating a mask via fls(). smp_num_siblings is guaranteed to be
a power of 2. So just using (smp_num_siblings - 1) has the same effect.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/cpu/topology.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
---
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -76,10 +76,7 @@ bool arch_match_cpu_phys_id(int cpu, u64
#ifdef CONFIG_SMP
static void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid)
{
- /* Isolate the SMT bit(s) in the APICID and check for 0 */
- u32 mask = (1U << (fls(smp_num_siblings) - 1)) - 1;
-
- if (smp_num_siblings == 1 || !(apicid & mask))
+ if (!(apicid & (smp_num_siblings - 1)))
cpumask_set_cpu(cpu, &__cpu_primary_thread_mask);
}
#else
next prev parent reply other threads:[~2024-02-13 21:06 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-13 21:05 [patch 00/30] x86/apic: Rework APIC registration Thomas Gleixner
2024-02-13 21:05 ` [patch 01/30] x86/cpu/topology: Move registration out of APIC code Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 02/30] x86/cpu/topology: Provide separate APIC registration functions Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 03/30] x86/acpi: Use new " Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 04/30] x86/jailhouse: Use new APIC registration function Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 05/30] x86/of: Use new APIC registration functions Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 06/30] x86/mpparse: Use new APIC registration function Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 07/30] x86/acpi: Dont invoke topology_register_apic() for XEN PV Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 08/30] x86/xen/smp_pv: Register fake APICs Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 09/30] x86/cpu/topology: Confine topology information Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 10/30] x86/cpu/topology: Simplify APIC registration Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 11/30] x86/cpu/topology: Use a data structure for topology info Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 12/30] x86/smpboot: Make error message actually useful Thomas Gleixner
2024-02-16 15:17 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 13/30] x86/cpu/topology: Sanitize the APIC admission logic Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 14/30] x86/cpu/topology: Rework possible CPU management Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 15/30] x86/cpu: Detect real BSP on crash kernels Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 16/30] x86/topology: Add a mechanism to track topology via APIC IDs Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 17/30] x86/cpu/topology: Reject unknown APIC IDs on ACPI hotplug Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:05 ` [patch 18/30] x86/cpu/topology: Assign hotpluggable CPUIDs during init Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 19/30] x86/xen/smp_pv: Count number of vCPUs early Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 20/30] x86/cpu/topology: Let XEN/PV use topology from CPUID/MADT Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 21/30] x86/cpu/topology: Use topology bitmaps for sizing Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 22/30] x86/cpu/topology: Mop up primary thread mask handling Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` Thomas Gleixner [this message]
2024-02-16 15:16 ` [tip: x86/apic] x86/cpu/topology: Simplify cpu_mark_primary_thread() tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 24/30] x86/cpu/topology: Provide logical pkg/die mapping Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 25/30] x86/cpu/topology: Use topology logical mapping mechanism Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 26/30] x86/cpu/topology: Retrieve cores per package from topology bitmaps Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 27/30] x86/cpu/topology: Rename smp_num_siblings Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 28/30] x86/cpu/topology: Rename topology_max_die_per_package() Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 29/30] x86/cpu/topology: Provide __num_[cores|threads]_per_package Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner
2024-02-13 21:06 ` [patch 30/30] x86/cpu/topology: Get rid of cpuinfo:: X86_max_cores Thomas Gleixner
2024-02-16 15:16 ` [tip: x86/apic] x86/cpu/topology: Get rid of cpuinfo::x86_max_cores tip-bot2 for Thomas Gleixner
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