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![Con Kolivas](/assets/img/avatar_default.png)
Remove the SMT-nice feature which idles sibling cpus on SMT cpus to facilitiate nice working properly where cpu power is shared. The idling of cpus in the presence of runnable tasks is considered too fragile, easy to break with outside code, and the complexity of managing this system if an architecture comes along with many logical cores sharing cpu power will be unworkable. Remove the associated per_cpu_gain variable in sched_domains used only by this code. Also: The reason is that with dynticks enabled, this code breaks without yet further tweaks so dynticks brought on the rapid demise of this code. So either we tweak this code or kill it off entirely. It was Ingo's preference to kill it off. Either way this needs to happen for 2.6.21 since dynticks has gone in. Signed-off-by: Con Kolivas <kernel@kolivas.org> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
206 lines
5.6 KiB
C
206 lines
5.6 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/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 <asm/topology.h>
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#ifndef node_has_online_mem
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#define node_has_online_mem(nid) (1)
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#endif
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#ifndef nr_cpus_node
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#define nr_cpus_node(node) \
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({ \
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cpumask_t __tmp__; \
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__tmp__ = node_to_cpumask(node); \
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cpus_weight(__tmp__); \
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})
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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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#ifndef node_distance
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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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#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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* then switch on zone reclaim on boot.
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*/
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#define RECLAIM_DISTANCE 20
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#endif
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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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/*
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* Below are the 3 major initializers used in building sched_domains:
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* SD_SIBLING_INIT, for SMT domains
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* SD_CPU_INIT, for SMP domains
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* SD_NODE_INIT, for NUMA domains
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*
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* Any architecture that cares to do any tuning to these values should do so
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* by defining their own arch-specific initializer in include/asm/topology.h.
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* A definition there will automagically override these default initializers
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* and allow arch-specific performance tuning of sched_domains.
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*/
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#ifdef CONFIG_SCHED_SMT
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/* MCD - Do we really need this? It is always on if CONFIG_SCHED_SMT is,
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* so can't we drop this in favor of CONFIG_SCHED_SMT?
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*/
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#define ARCH_HAS_SCHED_WAKE_IDLE
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/* Common values for SMT siblings */
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#ifndef SD_SIBLING_INIT
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#define SD_SIBLING_INIT (struct sched_domain) { \
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.span = CPU_MASK_NONE, \
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.parent = NULL, \
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.child = NULL, \
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.groups = NULL, \
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.min_interval = 1, \
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.max_interval = 2, \
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.busy_factor = 64, \
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.imbalance_pct = 110, \
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.cache_nice_tries = 0, \
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.busy_idx = 0, \
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.idle_idx = 0, \
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.newidle_idx = 1, \
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.wake_idx = 0, \
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.forkexec_idx = 0, \
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.flags = SD_LOAD_BALANCE \
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| SD_BALANCE_NEWIDLE \
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| SD_BALANCE_EXEC \
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| SD_WAKE_AFFINE \
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| SD_WAKE_IDLE \
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| SD_SHARE_CPUPOWER, \
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.last_balance = jiffies, \
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.balance_interval = 1, \
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.nr_balance_failed = 0, \
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}
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#endif
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#endif /* CONFIG_SCHED_SMT */
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#ifdef CONFIG_SCHED_MC
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/* Common values for MC siblings. for now mostly derived from SD_CPU_INIT */
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#ifndef SD_MC_INIT
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#define SD_MC_INIT (struct sched_domain) { \
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.span = CPU_MASK_NONE, \
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.parent = NULL, \
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.child = NULL, \
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.groups = NULL, \
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.min_interval = 1, \
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.max_interval = 4, \
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.busy_factor = 64, \
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.imbalance_pct = 125, \
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.cache_nice_tries = 1, \
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.busy_idx = 2, \
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.idle_idx = 1, \
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.newidle_idx = 2, \
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.wake_idx = 1, \
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.forkexec_idx = 1, \
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.flags = SD_LOAD_BALANCE \
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| SD_BALANCE_NEWIDLE \
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| SD_BALANCE_EXEC \
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| SD_WAKE_AFFINE \
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| SD_SHARE_PKG_RESOURCES\
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| BALANCE_FOR_MC_POWER, \
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.last_balance = jiffies, \
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.balance_interval = 1, \
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.nr_balance_failed = 0, \
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}
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#endif
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#endif /* CONFIG_SCHED_MC */
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/* Common values for CPUs */
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#ifndef SD_CPU_INIT
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#define SD_CPU_INIT (struct sched_domain) { \
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.span = CPU_MASK_NONE, \
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.parent = NULL, \
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.child = NULL, \
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.groups = NULL, \
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.min_interval = 1, \
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.max_interval = 4, \
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.busy_factor = 64, \
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.imbalance_pct = 125, \
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.cache_nice_tries = 1, \
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.busy_idx = 2, \
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.idle_idx = 1, \
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.newidle_idx = 2, \
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.wake_idx = 1, \
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.forkexec_idx = 1, \
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.flags = SD_LOAD_BALANCE \
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| SD_BALANCE_NEWIDLE \
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| SD_BALANCE_EXEC \
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| SD_WAKE_AFFINE \
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| BALANCE_FOR_PKG_POWER,\
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.last_balance = jiffies, \
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.balance_interval = 1, \
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.nr_balance_failed = 0, \
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}
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#endif
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/* sched_domains SD_ALLNODES_INIT for NUMA machines */
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#define SD_ALLNODES_INIT (struct sched_domain) { \
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.span = CPU_MASK_NONE, \
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.parent = NULL, \
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.child = NULL, \
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.groups = NULL, \
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.min_interval = 64, \
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.max_interval = 64*num_online_cpus(), \
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.busy_factor = 128, \
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.imbalance_pct = 133, \
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.cache_hot_time = (10*1000000), \
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.cache_nice_tries = 1, \
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.busy_idx = 3, \
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.idle_idx = 3, \
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.newidle_idx = 0, /* unused */ \
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.wake_idx = 0, /* unused */ \
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.forkexec_idx = 0, /* unused */ \
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.flags = SD_LOAD_BALANCE \
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| SD_SERIALIZE, \
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.last_balance = jiffies, \
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.balance_interval = 64, \
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.nr_balance_failed = 0, \
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}
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#ifdef CONFIG_NUMA
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#ifndef SD_NODE_INIT
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#error Please define an appropriate SD_NODE_INIT in include/asm/topology.h!!!
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#endif
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#endif /* CONFIG_NUMA */
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#endif /* _LINUX_TOPOLOGY_H */
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