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abaa93d9e1
RCU priority boosting currently checks for boosting via a pointer in task_struct. However, this is not needed: As Oleg noted, if the rt_mutex is placed in the rcu_node instead of on the booster's stack, the boostee can simply check it see if it owns the lock. This commit makes this change, shrinking task_struct by one pointer and the kernel by thirteen lines. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
609 lines
25 KiB
C
609 lines
25 KiB
C
/*
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* Read-Copy Update mechanism for mutual exclusion (tree-based version)
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* Internal non-public definitions.
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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, you can access it online at
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* http://www.gnu.org/licenses/gpl-2.0.html.
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*
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* Copyright IBM Corporation, 2008
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*
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* Author: Ingo Molnar <mingo@elte.hu>
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* Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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*/
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#include <linux/cache.h>
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#include <linux/spinlock.h>
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#include <linux/threads.h>
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#include <linux/cpumask.h>
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#include <linux/seqlock.h>
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#include <linux/irq_work.h>
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/*
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* Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and
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* CONFIG_RCU_FANOUT_LEAF.
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* In theory, it should be possible to add more levels straightforwardly.
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* In practice, this did work well going from three levels to four.
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* Of course, your mileage may vary.
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*/
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#define MAX_RCU_LVLS 4
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#define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF)
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#define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT)
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#define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT)
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#define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT)
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#if NR_CPUS <= RCU_FANOUT_1
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# define RCU_NUM_LVLS 1
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# define NUM_RCU_LVL_0 1
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# define NUM_RCU_LVL_1 (NR_CPUS)
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# define NUM_RCU_LVL_2 0
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# define NUM_RCU_LVL_3 0
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# define NUM_RCU_LVL_4 0
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#elif NR_CPUS <= RCU_FANOUT_2
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# define RCU_NUM_LVLS 2
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# define NUM_RCU_LVL_0 1
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# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
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# define NUM_RCU_LVL_2 (NR_CPUS)
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# define NUM_RCU_LVL_3 0
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# define NUM_RCU_LVL_4 0
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#elif NR_CPUS <= RCU_FANOUT_3
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# define RCU_NUM_LVLS 3
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# define NUM_RCU_LVL_0 1
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# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
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# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
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# define NUM_RCU_LVL_3 (NR_CPUS)
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# define NUM_RCU_LVL_4 0
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#elif NR_CPUS <= RCU_FANOUT_4
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# define RCU_NUM_LVLS 4
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# define NUM_RCU_LVL_0 1
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# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
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# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
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# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
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# define NUM_RCU_LVL_4 (NR_CPUS)
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#else
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# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
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#endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */
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#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4)
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#define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
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extern int rcu_num_lvls;
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extern int rcu_num_nodes;
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/*
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* Dynticks per-CPU state.
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*/
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struct rcu_dynticks {
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long long dynticks_nesting; /* Track irq/process nesting level. */
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/* Process level is worth LLONG_MAX/2. */
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int dynticks_nmi_nesting; /* Track NMI nesting level. */
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atomic_t dynticks; /* Even value for idle, else odd. */
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#ifdef CONFIG_NO_HZ_FULL_SYSIDLE
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long long dynticks_idle_nesting;
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/* irq/process nesting level from idle. */
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atomic_t dynticks_idle; /* Even value for idle, else odd. */
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/* "Idle" excludes userspace execution. */
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unsigned long dynticks_idle_jiffies;
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/* End of last non-NMI non-idle period. */
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#endif /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
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#ifdef CONFIG_RCU_FAST_NO_HZ
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bool all_lazy; /* Are all CPU's CBs lazy? */
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unsigned long nonlazy_posted;
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/* # times non-lazy CBs posted to CPU. */
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unsigned long nonlazy_posted_snap;
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/* idle-period nonlazy_posted snapshot. */
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unsigned long last_accelerate;
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/* Last jiffy CBs were accelerated. */
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unsigned long last_advance_all;
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/* Last jiffy CBs were all advanced. */
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int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
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#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
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};
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/* RCU's kthread states for tracing. */
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#define RCU_KTHREAD_STOPPED 0
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#define RCU_KTHREAD_RUNNING 1
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#define RCU_KTHREAD_WAITING 2
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#define RCU_KTHREAD_OFFCPU 3
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#define RCU_KTHREAD_YIELDING 4
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#define RCU_KTHREAD_MAX 4
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/*
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* Definition for node within the RCU grace-period-detection hierarchy.
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*/
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struct rcu_node {
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raw_spinlock_t lock; /* Root rcu_node's lock protects some */
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/* rcu_state fields as well as following. */
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unsigned long gpnum; /* Current grace period for this node. */
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/* This will either be equal to or one */
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/* behind the root rcu_node's gpnum. */
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unsigned long completed; /* Last GP completed for this node. */
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/* This will either be equal to or one */
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/* behind the root rcu_node's gpnum. */
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unsigned long qsmask; /* CPUs or groups that need to switch in */
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/* order for current grace period to proceed.*/
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/* In leaf rcu_node, each bit corresponds to */
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/* an rcu_data structure, otherwise, each */
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/* bit corresponds to a child rcu_node */
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/* structure. */
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unsigned long expmask; /* Groups that have ->blkd_tasks */
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/* elements that need to drain to allow the */
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/* current expedited grace period to */
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/* complete (only for TREE_PREEMPT_RCU). */
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unsigned long qsmaskinit;
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/* Per-GP initial value for qsmask & expmask. */
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unsigned long grpmask; /* Mask to apply to parent qsmask. */
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/* Only one bit will be set in this mask. */
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int grplo; /* lowest-numbered CPU or group here. */
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int grphi; /* highest-numbered CPU or group here. */
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u8 grpnum; /* CPU/group number for next level up. */
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u8 level; /* root is at level 0. */
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struct rcu_node *parent;
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struct list_head blkd_tasks;
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/* Tasks blocked in RCU read-side critical */
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/* section. Tasks are placed at the head */
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/* of this list and age towards the tail. */
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struct list_head *gp_tasks;
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/* Pointer to the first task blocking the */
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/* current grace period, or NULL if there */
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/* is no such task. */
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struct list_head *exp_tasks;
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/* Pointer to the first task blocking the */
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/* current expedited grace period, or NULL */
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/* if there is no such task. If there */
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/* is no current expedited grace period, */
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/* then there can cannot be any such task. */
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#ifdef CONFIG_RCU_BOOST
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struct list_head *boost_tasks;
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/* Pointer to first task that needs to be */
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/* priority boosted, or NULL if no priority */
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/* boosting is needed for this rcu_node */
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/* structure. If there are no tasks */
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/* queued on this rcu_node structure that */
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/* are blocking the current grace period, */
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/* there can be no such task. */
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struct completion boost_completion;
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/* Used to ensure that the rt_mutex used */
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/* to carry out the boosting is fully */
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/* released with no future boostee accesses */
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/* before that rt_mutex is re-initialized. */
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struct rt_mutex boost_mtx;
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/* Used only for the priority-boosting */
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/* side effect, not as a lock. */
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unsigned long boost_time;
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/* When to start boosting (jiffies). */
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struct task_struct *boost_kthread_task;
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/* kthread that takes care of priority */
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/* boosting for this rcu_node structure. */
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unsigned int boost_kthread_status;
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/* State of boost_kthread_task for tracing. */
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unsigned long n_tasks_boosted;
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/* Total number of tasks boosted. */
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unsigned long n_exp_boosts;
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/* Number of tasks boosted for expedited GP. */
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unsigned long n_normal_boosts;
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/* Number of tasks boosted for normal GP. */
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unsigned long n_balk_blkd_tasks;
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/* Refused to boost: no blocked tasks. */
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unsigned long n_balk_exp_gp_tasks;
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/* Refused to boost: nothing blocking GP. */
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unsigned long n_balk_boost_tasks;
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/* Refused to boost: already boosting. */
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unsigned long n_balk_notblocked;
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/* Refused to boost: RCU RS CS still running. */
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unsigned long n_balk_notyet;
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/* Refused to boost: not yet time. */
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unsigned long n_balk_nos;
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/* Refused to boost: not sure why, though. */
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/* This can happen due to race conditions. */
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#endif /* #ifdef CONFIG_RCU_BOOST */
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#ifdef CONFIG_RCU_NOCB_CPU
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wait_queue_head_t nocb_gp_wq[2];
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/* Place for rcu_nocb_kthread() to wait GP. */
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#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
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int need_future_gp[2];
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/* Counts of upcoming no-CB GP requests. */
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raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp;
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} ____cacheline_internodealigned_in_smp;
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/*
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* Do a full breadth-first scan of the rcu_node structures for the
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* specified rcu_state structure.
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*/
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#define rcu_for_each_node_breadth_first(rsp, rnp) \
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for ((rnp) = &(rsp)->node[0]; \
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(rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)
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/*
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* Do a breadth-first scan of the non-leaf rcu_node structures for the
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* specified rcu_state structure. Note that if there is a singleton
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* rcu_node tree with but one rcu_node structure, this loop is a no-op.
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*/
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#define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
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for ((rnp) = &(rsp)->node[0]; \
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(rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++)
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/*
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* Scan the leaves of the rcu_node hierarchy for the specified rcu_state
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* structure. Note that if there is a singleton rcu_node tree with but
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* one rcu_node structure, this loop -will- visit the rcu_node structure.
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* It is still a leaf node, even if it is also the root node.
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*/
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#define rcu_for_each_leaf_node(rsp, rnp) \
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for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \
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(rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)
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/* Index values for nxttail array in struct rcu_data. */
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#define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */
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#define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */
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#define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */
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#define RCU_NEXT_TAIL 3
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#define RCU_NEXT_SIZE 4
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/* Per-CPU data for read-copy update. */
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struct rcu_data {
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/* 1) quiescent-state and grace-period handling : */
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unsigned long completed; /* Track rsp->completed gp number */
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/* in order to detect GP end. */
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unsigned long gpnum; /* Highest gp number that this CPU */
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/* is aware of having started. */
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bool passed_quiesce; /* User-mode/idle loop etc. */
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bool qs_pending; /* Core waits for quiesc state. */
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bool beenonline; /* CPU online at least once. */
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struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
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unsigned long grpmask; /* Mask to apply to leaf qsmask. */
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#ifdef CONFIG_RCU_CPU_STALL_INFO
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unsigned long ticks_this_gp; /* The number of scheduling-clock */
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/* ticks this CPU has handled */
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/* during and after the last grace */
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/* period it is aware of. */
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#endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
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/* 2) batch handling */
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/*
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* If nxtlist is not NULL, it is partitioned as follows.
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* Any of the partitions might be empty, in which case the
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* pointer to that partition will be equal to the pointer for
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* the following partition. When the list is empty, all of
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* the nxttail elements point to the ->nxtlist pointer itself,
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* which in that case is NULL.
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*
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* [nxtlist, *nxttail[RCU_DONE_TAIL]):
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* Entries that batch # <= ->completed
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* The grace period for these entries has completed, and
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* the other grace-period-completed entries may be moved
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* here temporarily in rcu_process_callbacks().
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* [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
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* Entries that batch # <= ->completed - 1: waiting for current GP
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* [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
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* Entries known to have arrived before current GP ended
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* [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]):
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* Entries that might have arrived after current GP ended
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* Note that the value of *nxttail[RCU_NEXT_TAIL] will
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* always be NULL, as this is the end of the list.
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*/
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struct rcu_head *nxtlist;
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struct rcu_head **nxttail[RCU_NEXT_SIZE];
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unsigned long nxtcompleted[RCU_NEXT_SIZE];
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/* grace periods for sublists. */
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long qlen_lazy; /* # of lazy queued callbacks */
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long qlen; /* # of queued callbacks, incl lazy */
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long qlen_last_fqs_check;
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/* qlen at last check for QS forcing */
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unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */
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unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */
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unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */
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unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */
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unsigned long n_force_qs_snap;
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/* did other CPU force QS recently? */
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long blimit; /* Upper limit on a processed batch */
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/* 3) dynticks interface. */
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struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */
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int dynticks_snap; /* Per-GP tracking for dynticks. */
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/* 4) reasons this CPU needed to be kicked by force_quiescent_state */
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unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */
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unsigned long offline_fqs; /* Kicked due to being offline. */
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unsigned long cond_resched_completed;
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/* Grace period that needs help */
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/* from cond_resched(). */
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/* 5) __rcu_pending() statistics. */
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unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */
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unsigned long n_rp_qs_pending;
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unsigned long n_rp_report_qs;
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unsigned long n_rp_cb_ready;
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unsigned long n_rp_cpu_needs_gp;
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unsigned long n_rp_gp_completed;
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unsigned long n_rp_gp_started;
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unsigned long n_rp_nocb_defer_wakeup;
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unsigned long n_rp_need_nothing;
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/* 6) _rcu_barrier() and OOM callbacks. */
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struct rcu_head barrier_head;
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#ifdef CONFIG_RCU_FAST_NO_HZ
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struct rcu_head oom_head;
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#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
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/* 7) Callback offloading. */
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#ifdef CONFIG_RCU_NOCB_CPU
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struct rcu_head *nocb_head; /* CBs waiting for kthread. */
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struct rcu_head **nocb_tail;
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atomic_long_t nocb_q_count; /* # CBs waiting for kthread */
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atomic_long_t nocb_q_count_lazy; /* (approximate). */
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int nocb_p_count; /* # CBs being invoked by kthread */
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int nocb_p_count_lazy; /* (approximate). */
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wait_queue_head_t nocb_wq; /* For nocb kthreads to sleep on. */
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struct task_struct *nocb_kthread;
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bool nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */
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#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
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/* 8) RCU CPU stall data. */
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#ifdef CONFIG_RCU_CPU_STALL_INFO
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unsigned int softirq_snap; /* Snapshot of softirq activity. */
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#endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
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int cpu;
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struct rcu_state *rsp;
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};
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/* Values for fqs_state field in struct rcu_state. */
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#define RCU_GP_IDLE 0 /* No grace period in progress. */
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#define RCU_GP_INIT 1 /* Grace period being initialized. */
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#define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */
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#define RCU_FORCE_QS 3 /* Need to force quiescent state. */
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#define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK
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#define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500))
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/* For jiffies_till_first_fqs and */
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/* and jiffies_till_next_fqs. */
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#define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */
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/* delay between bouts of */
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/* quiescent-state forcing. */
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#define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */
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/* at least one scheduling clock */
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/* irq before ratting on them. */
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#define rcu_wait(cond) \
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do { \
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for (;;) { \
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set_current_state(TASK_INTERRUPTIBLE); \
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if (cond) \
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break; \
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schedule(); \
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} \
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__set_current_state(TASK_RUNNING); \
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} while (0)
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/*
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* RCU global state, including node hierarchy. This hierarchy is
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* represented in "heap" form in a dense array. The root (first level)
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* of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
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* level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
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* and the third level in ->node[m+1] and following (->node[m+1] referenced
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* by ->level[2]). The number of levels is determined by the number of
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* CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy"
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* consisting of a single rcu_node.
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*/
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struct rcu_state {
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struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
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struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */
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u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */
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u8 levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */
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u8 flavor_mask; /* bit in flavor mask. */
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struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */
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void (*call)(struct rcu_head *head, /* call_rcu() flavor. */
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void (*func)(struct rcu_head *head));
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/* The following fields are guarded by the root rcu_node's lock. */
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u8 fqs_state ____cacheline_internodealigned_in_smp;
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/* Force QS state. */
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u8 boost; /* Subject to priority boost. */
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unsigned long gpnum; /* Current gp number. */
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unsigned long completed; /* # of last completed gp. */
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struct task_struct *gp_kthread; /* Task for grace periods. */
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wait_queue_head_t gp_wq; /* Where GP task waits. */
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short gp_flags; /* Commands for GP task. */
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short gp_state; /* GP kthread sleep state. */
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/* End of fields guarded by root rcu_node's lock. */
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raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp;
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/* Protect following fields. */
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struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */
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/* need a grace period. */
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struct rcu_head **orphan_nxttail; /* Tail of above. */
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struct rcu_head *orphan_donelist; /* Orphaned callbacks that */
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/* are ready to invoke. */
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struct rcu_head **orphan_donetail; /* Tail of above. */
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long qlen_lazy; /* Number of lazy callbacks. */
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long qlen; /* Total number of callbacks. */
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/* End of fields guarded by orphan_lock. */
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struct mutex onoff_mutex; /* Coordinate hotplug & GPs. */
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struct mutex barrier_mutex; /* Guards barrier fields. */
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atomic_t barrier_cpu_count; /* # CPUs waiting on. */
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struct completion barrier_completion; /* Wake at barrier end. */
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unsigned long n_barrier_done; /* ++ at start and end of */
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/* _rcu_barrier(). */
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/* End of fields guarded by barrier_mutex. */
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atomic_long_t expedited_start; /* Starting ticket. */
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atomic_long_t expedited_done; /* Done ticket. */
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atomic_long_t expedited_wrap; /* # near-wrap incidents. */
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atomic_long_t expedited_tryfail; /* # acquisition failures. */
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atomic_long_t expedited_workdone1; /* # done by others #1. */
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atomic_long_t expedited_workdone2; /* # done by others #2. */
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atomic_long_t expedited_normal; /* # fallbacks to normal. */
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atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */
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atomic_long_t expedited_done_tries; /* # tries to update _done. */
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atomic_long_t expedited_done_lost; /* # times beaten to _done. */
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atomic_long_t expedited_done_exit; /* # times exited _done loop. */
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|
|
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unsigned long jiffies_force_qs; /* Time at which to invoke */
|
|
/* force_quiescent_state(). */
|
|
unsigned long n_force_qs; /* Number of calls to */
|
|
/* force_quiescent_state(). */
|
|
unsigned long n_force_qs_lh; /* ~Number of calls leaving */
|
|
/* due to lock unavailable. */
|
|
unsigned long n_force_qs_ngp; /* Number of calls leaving */
|
|
/* due to no GP active. */
|
|
unsigned long gp_start; /* Time at which GP started, */
|
|
/* but in jiffies. */
|
|
unsigned long jiffies_stall; /* Time at which to check */
|
|
/* for CPU stalls. */
|
|
unsigned long jiffies_resched; /* Time at which to resched */
|
|
/* a reluctant CPU. */
|
|
unsigned long gp_max; /* Maximum GP duration in */
|
|
/* jiffies. */
|
|
const char *name; /* Name of structure. */
|
|
char abbr; /* Abbreviated name. */
|
|
struct list_head flavors; /* List of RCU flavors. */
|
|
};
|
|
|
|
/* Values for rcu_state structure's gp_flags field. */
|
|
#define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */
|
|
#define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */
|
|
|
|
/* Values for rcu_state structure's gp_flags field. */
|
|
#define RCU_GP_WAIT_INIT 0 /* Initial state. */
|
|
#define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */
|
|
#define RCU_GP_WAIT_FQS 2 /* Wait for force-quiescent-state time. */
|
|
|
|
extern struct list_head rcu_struct_flavors;
|
|
|
|
/* Sequence through rcu_state structures for each RCU flavor. */
|
|
#define for_each_rcu_flavor(rsp) \
|
|
list_for_each_entry((rsp), &rcu_struct_flavors, flavors)
|
|
|
|
/* Return values for rcu_preempt_offline_tasks(). */
|
|
|
|
#define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */
|
|
/* GP were moved to root. */
|
|
#define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */
|
|
/* GP were moved to root. */
|
|
|
|
/*
|
|
* RCU implementation internal declarations:
|
|
*/
|
|
extern struct rcu_state rcu_sched_state;
|
|
DECLARE_PER_CPU(struct rcu_data, rcu_sched_data);
|
|
|
|
extern struct rcu_state rcu_bh_state;
|
|
DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
|
|
|
|
#ifdef CONFIG_TREE_PREEMPT_RCU
|
|
extern struct rcu_state rcu_preempt_state;
|
|
DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
|
|
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
|
|
|
|
#ifdef CONFIG_RCU_BOOST
|
|
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
|
|
DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
|
|
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
|
|
DECLARE_PER_CPU(char, rcu_cpu_has_work);
|
|
#endif /* #ifdef CONFIG_RCU_BOOST */
|
|
|
|
#ifndef RCU_TREE_NONCORE
|
|
|
|
/* Forward declarations for rcutree_plugin.h */
|
|
static void rcu_bootup_announce(void);
|
|
long rcu_batches_completed(void);
|
|
static void rcu_preempt_note_context_switch(int cpu);
|
|
static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
|
|
unsigned long flags);
|
|
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
|
|
static void rcu_print_detail_task_stall(struct rcu_state *rsp);
|
|
static int rcu_print_task_stall(struct rcu_node *rnp);
|
|
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
|
|
struct rcu_node *rnp,
|
|
struct rcu_data *rdp);
|
|
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
|
|
static void rcu_preempt_check_callbacks(int cpu);
|
|
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
|
|
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU)
|
|
static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
|
|
bool wake);
|
|
#endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */
|
|
static void __init __rcu_init_preempt(void);
|
|
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
|
|
static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
|
|
static void invoke_rcu_callbacks_kthread(void);
|
|
static bool rcu_is_callbacks_kthread(void);
|
|
#ifdef CONFIG_RCU_BOOST
|
|
static void rcu_preempt_do_callbacks(void);
|
|
static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
|
|
struct rcu_node *rnp);
|
|
#endif /* #ifdef CONFIG_RCU_BOOST */
|
|
static void rcu_prepare_kthreads(int cpu);
|
|
static void rcu_cleanup_after_idle(int cpu);
|
|
static void rcu_prepare_for_idle(int cpu);
|
|
static void rcu_idle_count_callbacks_posted(void);
|
|
static void print_cpu_stall_info_begin(void);
|
|
static void print_cpu_stall_info(struct rcu_state *rsp, int cpu);
|
|
static void print_cpu_stall_info_end(void);
|
|
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
|
|
static void increment_cpu_stall_ticks(void);
|
|
static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq);
|
|
static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp);
|
|
static void rcu_init_one_nocb(struct rcu_node *rnp);
|
|
static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
|
|
bool lazy, unsigned long flags);
|
|
static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
|
|
struct rcu_data *rdp,
|
|
unsigned long flags);
|
|
static bool rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
|
|
static void do_nocb_deferred_wakeup(struct rcu_data *rdp);
|
|
static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
|
|
static void rcu_spawn_nocb_kthreads(struct rcu_state *rsp);
|
|
static void __maybe_unused rcu_kick_nohz_cpu(int cpu);
|
|
static bool init_nocb_callback_list(struct rcu_data *rdp);
|
|
static void rcu_sysidle_enter(struct rcu_dynticks *rdtp, int irq);
|
|
static void rcu_sysidle_exit(struct rcu_dynticks *rdtp, int irq);
|
|
static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle,
|
|
unsigned long *maxj);
|
|
static bool is_sysidle_rcu_state(struct rcu_state *rsp);
|
|
static void rcu_sysidle_report_gp(struct rcu_state *rsp, int isidle,
|
|
unsigned long maxj);
|
|
static void rcu_bind_gp_kthread(void);
|
|
static void rcu_sysidle_init_percpu_data(struct rcu_dynticks *rdtp);
|
|
static bool rcu_nohz_full_cpu(struct rcu_state *rsp);
|
|
|
|
#endif /* #ifndef RCU_TREE_NONCORE */
|
|
|
|
#ifdef CONFIG_RCU_TRACE
|
|
#ifdef CONFIG_RCU_NOCB_CPU
|
|
/* Sum up queue lengths for tracing. */
|
|
static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
|
|
{
|
|
*ql = atomic_long_read(&rdp->nocb_q_count) + rdp->nocb_p_count;
|
|
*qll = atomic_long_read(&rdp->nocb_q_count_lazy) + rdp->nocb_p_count_lazy;
|
|
}
|
|
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
|
|
static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
|
|
{
|
|
*ql = 0;
|
|
*qll = 0;
|
|
}
|
|
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
|
|
#endif /* #ifdef CONFIG_RCU_TRACE */
|