rcu: slim down rcutiny by removing rcu_scheduler_active and friends
TINY_RCU does not need rcu_scheduler_active unless CONFIG_DEBUG_LOCK_ALLOC. So conditionally compile rcu_scheduler_active in order to slim down rcutiny a bit more. Also gets rid of an EXPORT_SYMBOL_GPL, which is responsible for most of the slimming. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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25502a6c13
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bbad937983
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@ -64,8 +64,6 @@ extern int sched_expedited_torture_stats(char *page);
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/* Internal to kernel */
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extern void rcu_init(void);
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extern int rcu_scheduler_active;
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extern void rcu_scheduler_starting(void);
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#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
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#include <linux/rcutree.h>
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@ -178,7 +176,7 @@ static inline int rcu_read_lock_bh_held(void)
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#ifdef CONFIG_PREEMPT
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static inline int rcu_read_lock_sched_held(void)
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{
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return !rcu_scheduler_active || preempt_count() != 0 || irqs_disabled();
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return preempt_count() != 0 || irqs_disabled();
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}
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#else /* #ifdef CONFIG_PREEMPT */
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static inline int rcu_read_lock_sched_held(void)
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@ -128,4 +128,17 @@ static inline int rcu_preempt_depth(void)
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return 0;
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}
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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extern int rcu_scheduler_active __read_mostly;
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extern void rcu_scheduler_starting(void);
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#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
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static inline void rcu_scheduler_starting(void)
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{
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}
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#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
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#endif /* __LINUX_RCUTINY_H */
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@ -123,4 +123,7 @@ static inline int rcu_blocking_is_gp(void)
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return num_online_cpus() == 1;
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}
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extern void rcu_scheduler_starting(void);
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extern int rcu_scheduler_active __read_mostly;
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#endif /* __LINUX_RCUTREE_H */
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@ -44,7 +44,6 @@
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#include <linux/cpu.h>
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#include <linux/mutex.h>
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#include <linux/module.h>
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#include <linux/kernel_stat.h>
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#include <linux/hardirq.h>
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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@ -64,9 +63,6 @@ struct lockdep_map rcu_sched_lock_map =
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EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
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#endif
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int rcu_scheduler_active __read_mostly;
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EXPORT_SYMBOL_GPL(rcu_scheduler_active);
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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int debug_lockdep_rcu_enabled(void)
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@ -96,21 +92,6 @@ EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
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#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
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/*
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* This function is invoked towards the end of the scheduler's initialization
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* process. Before this is called, the idle task might contain
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* RCU read-side critical sections (during which time, this idle
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* task is booting the system). After this function is called, the
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* idle tasks are prohibited from containing RCU read-side critical
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* sections.
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*/
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void rcu_scheduler_starting(void)
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{
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WARN_ON(num_online_cpus() != 1);
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WARN_ON(nr_context_switches() > 0);
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rcu_scheduler_active = 1;
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}
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/*
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* Awaken the corresponding synchronize_rcu() instance now that a
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* grace period has elapsed.
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@ -54,6 +54,11 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = {
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.curtail = &rcu_bh_ctrlblk.rcucblist,
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};
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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int rcu_scheduler_active __read_mostly;
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EXPORT_SYMBOL_GPL(rcu_scheduler_active);
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#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
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#ifdef CONFIG_NO_HZ
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static long rcu_dynticks_nesting = 1;
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@ -276,3 +281,5 @@ void __init rcu_init(void)
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{
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open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
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}
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#include "rcutiny_plugin.h"
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@ -0,0 +1,39 @@
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/*
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* Read-Copy Update mechanism for mutual exclusion (tree-based version)
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* Internal non-public definitions that provide either classic
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* or preemptable semantics.
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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,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright IBM Corporation, 2009
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*
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* Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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*/
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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#include <linux/kernel_stat.h>
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/*
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* During boot, we forgive RCU lockdep issues. After this function is
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* invoked, we start taking RCU lockdep issues seriously.
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*/
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void rcu_scheduler_starting(void)
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{
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WARN_ON(nr_context_switches() > 0);
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rcu_scheduler_active = 1;
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}
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#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
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@ -46,6 +46,7 @@
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#include <linux/cpu.h>
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#include <linux/mutex.h>
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#include <linux/time.h>
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#include <linux/kernel_stat.h>
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#include "rcutree.h"
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@ -80,6 +81,9 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
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struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
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DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
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int rcu_scheduler_active __read_mostly;
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EXPORT_SYMBOL_GPL(rcu_scheduler_active);
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/*
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* Return true if an RCU grace period is in progress. The ACCESS_ONCE()s
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* permit this function to be invoked without holding the root rcu_node
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@ -1783,6 +1787,21 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
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return NOTIFY_OK;
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}
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/*
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* This function is invoked towards the end of the scheduler's initialization
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* process. Before this is called, the idle task might contain
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* RCU read-side critical sections (during which time, this idle
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* task is booting the system). After this function is called, the
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* idle tasks are prohibited from containing RCU read-side critical
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* sections. This function also enables RCU lockdep checking.
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*/
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void rcu_scheduler_starting(void)
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{
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WARN_ON(num_online_cpus() != 1);
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WARN_ON(nr_context_switches() > 0);
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rcu_scheduler_active = 1;
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}
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/*
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* Compute the per-level fanout, either using the exact fanout specified
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* or balancing the tree, depending on CONFIG_RCU_FANOUT_EXACT.
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