forked from mirrors/linux
3babbe447d
cpu_smt_mask tracks topology_sibling_cpumask. This would be good for most architectures. One of the users of cpu_smt_mask(), would be to identify idle-cores. On Power9, a pair of SMT4 cores can be presented by the firmware as a SMT8 core for backward compatibility reasons. powerpc allows LPARs to be live migrated from Power8 to Power9. Do note Power8 had only SMT8 cores. Existing software which has been developed/configured for Power8 would expect to see SMT8 core. Maintaining the illusion of SMT8 core is a requirement to make that work. In order to maintain above userspace backward compatibility with previous versions of processor, Power9 onwards there is option to the firmware to advertise a pair of SMT4 cores as a fused cores aka SMT8 core. On Power9 this pair shares the L2 cache as well. However, from the scheduler's point of view, a core should be determined by SMT4, since its a completely independent unit of compute. Hence allow powerpc architecture to override the default cpu_smt_mask() to point to the SMT4 cores in a SMT8 mode. This will ensure the scheduler is always given the right information. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200807074517.27957-1-srikar@linux.vnet.ibm.com
214 lines
5.2 KiB
C
214 lines
5.2 KiB
C
/*
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* include/linux/topology.h
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*
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* Written by: Matthew Dobson, IBM Corporation
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*
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* Copyright (C) 2002, IBM Corp.
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Send feedback to <colpatch@us.ibm.com>
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*/
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#ifndef _LINUX_TOPOLOGY_H
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#define _LINUX_TOPOLOGY_H
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#include <linux/arch_topology.h>
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#include <linux/cpumask.h>
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#include <linux/bitops.h>
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#include <linux/mmzone.h>
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#include <linux/smp.h>
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#include <linux/percpu.h>
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#include <asm/topology.h>
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#ifndef nr_cpus_node
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#define nr_cpus_node(node) cpumask_weight(cpumask_of_node(node))
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#endif
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#define for_each_node_with_cpus(node) \
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for_each_online_node(node) \
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if (nr_cpus_node(node))
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int arch_update_cpu_topology(void);
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/* Conform to ACPI 2.0 SLIT distance definitions */
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#define LOCAL_DISTANCE 10
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#define REMOTE_DISTANCE 20
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#ifndef node_distance
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#define node_distance(from,to) ((from) == (to) ? LOCAL_DISTANCE : REMOTE_DISTANCE)
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#endif
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#ifndef RECLAIM_DISTANCE
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/*
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* If the distance between nodes in a system is larger than RECLAIM_DISTANCE
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* (in whatever arch specific measurement units returned by node_distance())
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* and node_reclaim_mode is enabled then the VM will only call node_reclaim()
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* on nodes within this distance.
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*/
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#define RECLAIM_DISTANCE 30
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#endif
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/*
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* The following tunable allows platforms to override the default node
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* reclaim distance (RECLAIM_DISTANCE) if remote memory accesses are
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* sufficiently fast that the default value actually hurts
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* performance.
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*
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* AMD EPYC machines use this because even though the 2-hop distance
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* is 32 (3.2x slower than a local memory access) performance actually
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* *improves* if allowed to reclaim memory and load balance tasks
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* between NUMA nodes 2-hops apart.
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*/
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extern int __read_mostly node_reclaim_distance;
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#ifndef PENALTY_FOR_NODE_WITH_CPUS
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#define PENALTY_FOR_NODE_WITH_CPUS (1)
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#endif
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#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
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DECLARE_PER_CPU(int, numa_node);
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#ifndef numa_node_id
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/* Returns the number of the current Node. */
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static inline int numa_node_id(void)
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{
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return raw_cpu_read(numa_node);
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}
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#endif
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#ifndef cpu_to_node
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static inline int cpu_to_node(int cpu)
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{
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return per_cpu(numa_node, cpu);
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}
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#endif
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#ifndef set_numa_node
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static inline void set_numa_node(int node)
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{
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this_cpu_write(numa_node, node);
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}
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#endif
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#ifndef set_cpu_numa_node
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static inline void set_cpu_numa_node(int cpu, int node)
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{
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per_cpu(numa_node, cpu) = node;
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}
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#endif
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#else /* !CONFIG_USE_PERCPU_NUMA_NODE_ID */
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/* Returns the number of the current Node. */
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#ifndef numa_node_id
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static inline int numa_node_id(void)
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{
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return cpu_to_node(raw_smp_processor_id());
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}
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#endif
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#endif /* [!]CONFIG_USE_PERCPU_NUMA_NODE_ID */
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#ifdef CONFIG_HAVE_MEMORYLESS_NODES
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/*
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* N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
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* It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
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* Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem().
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*/
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DECLARE_PER_CPU(int, _numa_mem_);
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#ifndef set_numa_mem
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static inline void set_numa_mem(int node)
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{
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this_cpu_write(_numa_mem_, node);
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}
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#endif
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#ifndef numa_mem_id
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/* Returns the number of the nearest Node with memory */
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static inline int numa_mem_id(void)
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{
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return raw_cpu_read(_numa_mem_);
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}
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#endif
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#ifndef cpu_to_mem
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static inline int cpu_to_mem(int cpu)
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{
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return per_cpu(_numa_mem_, cpu);
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}
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#endif
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#ifndef set_cpu_numa_mem
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static inline void set_cpu_numa_mem(int cpu, int node)
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{
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per_cpu(_numa_mem_, cpu) = node;
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}
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#endif
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#else /* !CONFIG_HAVE_MEMORYLESS_NODES */
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#ifndef numa_mem_id
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/* Returns the number of the nearest Node with memory */
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static inline int numa_mem_id(void)
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{
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return numa_node_id();
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}
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#endif
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#ifndef cpu_to_mem
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static inline int cpu_to_mem(int cpu)
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{
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return cpu_to_node(cpu);
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}
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#endif
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#endif /* [!]CONFIG_HAVE_MEMORYLESS_NODES */
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#ifndef topology_physical_package_id
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#define topology_physical_package_id(cpu) ((void)(cpu), -1)
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#endif
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#ifndef topology_die_id
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#define topology_die_id(cpu) ((void)(cpu), -1)
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#endif
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#ifndef topology_core_id
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#define topology_core_id(cpu) ((void)(cpu), 0)
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#endif
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#ifndef topology_sibling_cpumask
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#define topology_sibling_cpumask(cpu) cpumask_of(cpu)
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#endif
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#ifndef topology_core_cpumask
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#define topology_core_cpumask(cpu) cpumask_of(cpu)
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#endif
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#ifndef topology_die_cpumask
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#define topology_die_cpumask(cpu) cpumask_of(cpu)
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#endif
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#if defined(CONFIG_SCHED_SMT) && !defined(cpu_smt_mask)
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static inline const struct cpumask *cpu_smt_mask(int cpu)
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{
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return topology_sibling_cpumask(cpu);
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}
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#endif
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static inline const struct cpumask *cpu_cpu_mask(int cpu)
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{
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return cpumask_of_node(cpu_to_node(cpu));
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}
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#endif /* _LINUX_TOPOLOGY_H */
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