forked from luck/tmp_suning_uos_patched
0aa04b055e
Races between CPU hotplug and grace periods can be difficult to resolve, so the ->onoff_mutex is used to exclude the two events. Unfortunately, this means that it is impossible for an outgoing CPU to perform the last bits of its offlining from its last pass through the idle loop, because sleeplocks cannot be acquired in that context. This commit avoids these problems by buffering online and offline events in a new ->qsmaskinitnext field in the leaf rcu_node structures. When a grace period starts, the events accumulated in this mask are applied to the ->qsmaskinit field, and, if needed, up the rcu_node tree. The special case of all CPUs corresponding to a given leaf rcu_node structure being offline while there are still elements in that structure's ->blkd_tasks list is handled using a new ->wait_blkd_tasks field. In this case, propagating the offline bits up the tree is deferred until the beginning of the grace period after all of the tasks have exited their RCU read-side critical sections and removed themselves from the list, at which point the ->wait_blkd_tasks flag is cleared. If one of that leaf rcu_node structure's CPUs comes back online before the list empties, then the ->wait_blkd_tasks flag is simply cleared. This of course means that RCU's notion of which CPUs are offline can be out of date. This is OK because RCU need only wait on CPUs that were online at the time that the grace period started. In addition, RCU's force-quiescent-state actions will handle the case where a CPU goes offline after the grace period starts. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
623 lines
25 KiB
C
623 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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/*
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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 PREEMPT_RCU). */
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unsigned long qsmaskinit;
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/* Per-GP initial value for qsmask & expmask. */
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/* Initialized from ->qsmaskinitnext at the */
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/* beginning of each grace period. */
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unsigned long qsmaskinitnext;
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/* Online CPUs for next grace period. */
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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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bool wait_blkd_tasks;/* Necessary to wait for blocked tasks to */
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/* exit RCU read-side critical sections */
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/* before propagating offline up the */
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/* rcu_node tree? */
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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 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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unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
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/* for rcu_all_qs() invocations. */
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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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bool gpwrap; /* Possible gpnum/completed wrap. */
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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 nocb */
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atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */
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struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */
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struct rcu_head **nocb_follower_tail;
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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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int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */
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/* The following fields are used by the leader, hence own cacheline. */
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struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp;
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/* CBs waiting for GP. */
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struct rcu_head **nocb_gp_tail;
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bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */
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struct rcu_data *nocb_next_follower;
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/* Next follower in wakeup chain. */
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/* The following fields are used by the follower, hence new cachline. */
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struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp;
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/* Leader CPU takes GP-end wakeups. */
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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
|
|
|
|
/* Values for nocb_defer_wakeup field in struct rcu_data. */
|
|
#define RCU_NOGP_WAKE_NOT 0
|
|
#define RCU_NOGP_WAKE 1
|
|
#define RCU_NOGP_WAKE_FORCE 2
|
|
|
|
#define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500))
|
|
/* For jiffies_till_first_fqs and */
|
|
/* and jiffies_till_next_fqs. */
|
|
|
|
#define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */
|
|
/* delay between bouts of */
|
|
/* quiescent-state forcing. */
|
|
|
|
#define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */
|
|
/* at least one scheduling clock */
|
|
/* irq before ratting on them. */
|
|
|
|
#define rcu_wait(cond) \
|
|
do { \
|
|
for (;;) { \
|
|
set_current_state(TASK_INTERRUPTIBLE); \
|
|
if (cond) \
|
|
break; \
|
|
schedule(); \
|
|
} \
|
|
__set_current_state(TASK_RUNNING); \
|
|
} while (0)
|
|
|
|
/*
|
|
* RCU global state, including node hierarchy. This hierarchy is
|
|
* represented in "heap" form in a dense array. The root (first level)
|
|
* of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
|
|
* level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
|
|
* and the third level in ->node[m+1] and following (->node[m+1] referenced
|
|
* by ->level[2]). The number of levels is determined by the number of
|
|
* CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy"
|
|
* consisting of a single rcu_node.
|
|
*/
|
|
struct rcu_state {
|
|
struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
|
|
struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */
|
|
u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */
|
|
u8 levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */
|
|
u8 flavor_mask; /* bit in flavor mask. */
|
|
struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */
|
|
void (*call)(struct rcu_head *head, /* call_rcu() flavor. */
|
|
void (*func)(struct rcu_head *head));
|
|
|
|
/* The following fields are guarded by the root rcu_node's lock. */
|
|
|
|
u8 fqs_state ____cacheline_internodealigned_in_smp;
|
|
/* Force QS state. */
|
|
u8 boost; /* Subject to priority boost. */
|
|
unsigned long gpnum; /* Current gp number. */
|
|
unsigned long completed; /* # of last completed gp. */
|
|
struct task_struct *gp_kthread; /* Task for grace periods. */
|
|
wait_queue_head_t gp_wq; /* Where GP task waits. */
|
|
short gp_flags; /* Commands for GP task. */
|
|
short gp_state; /* GP kthread sleep state. */
|
|
|
|
/* End of fields guarded by root rcu_node's lock. */
|
|
|
|
raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp;
|
|
/* Protect following fields. */
|
|
struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */
|
|
/* need a grace period. */
|
|
struct rcu_head **orphan_nxttail; /* Tail of above. */
|
|
struct rcu_head *orphan_donelist; /* Orphaned callbacks that */
|
|
/* are ready to invoke. */
|
|
struct rcu_head **orphan_donetail; /* Tail of above. */
|
|
long qlen_lazy; /* Number of lazy callbacks. */
|
|
long qlen; /* Total number of callbacks. */
|
|
/* End of fields guarded by orphan_lock. */
|
|
|
|
struct mutex onoff_mutex; /* Coordinate hotplug & GPs. */
|
|
|
|
struct mutex barrier_mutex; /* Guards barrier fields. */
|
|
atomic_t barrier_cpu_count; /* # CPUs waiting on. */
|
|
struct completion barrier_completion; /* Wake at barrier end. */
|
|
unsigned long n_barrier_done; /* ++ at start and end of */
|
|
/* _rcu_barrier(). */
|
|
/* End of fields guarded by barrier_mutex. */
|
|
|
|
atomic_long_t expedited_start; /* Starting ticket. */
|
|
atomic_long_t expedited_done; /* Done ticket. */
|
|
atomic_long_t expedited_wrap; /* # near-wrap incidents. */
|
|
atomic_long_t expedited_tryfail; /* # acquisition failures. */
|
|
atomic_long_t expedited_workdone1; /* # done by others #1. */
|
|
atomic_long_t expedited_workdone2; /* # done by others #2. */
|
|
atomic_long_t expedited_normal; /* # fallbacks to normal. */
|
|
atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */
|
|
atomic_long_t expedited_done_tries; /* # tries to update _done. */
|
|
atomic_long_t expedited_done_lost; /* # times beaten to _done. */
|
|
atomic_long_t expedited_done_exit; /* # times exited _done loop. */
|
|
|
|
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 gp_activity; /* Time of last GP kthread */
|
|
/* activity 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 n_force_qs_gpstart; /* Snapshot of n_force_qs at */
|
|
/* GP start. */
|
|
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)
|
|
|
|
/*
|
|
* 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_PREEMPT_RCU
|
|
extern struct rcu_state rcu_preempt_state;
|
|
DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
|
|
#endif /* #ifdef CONFIG_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);
|
|
static void rcu_preempt_note_context_switch(void);
|
|
static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
|
|
#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);
|
|
static void rcu_preempt_check_callbacks(void);
|
|
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *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 __init rcu_spawn_boost_kthreads(void);
|
|
static void rcu_prepare_kthreads(int cpu);
|
|
static void rcu_cleanup_after_idle(void);
|
|
static void rcu_prepare_for_idle(void);
|
|
static void rcu_idle_count_callbacks_posted(void);
|
|
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
|
|
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 bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu);
|
|
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 int 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_all_nocb_kthreads(int cpu);
|
|
static void __init rcu_spawn_nocb_kthreads(void);
|
|
#ifdef CONFIG_RCU_NOCB_CPU
|
|
static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp);
|
|
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
|
|
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(int irq);
|
|
static void rcu_sysidle_exit(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);
|
|
static void rcu_dynticks_task_enter(void);
|
|
static void rcu_dynticks_task_exit(void);
|
|
|
|
#endif /* #ifndef RCU_TREE_NONCORE */
|
|
|
|
#ifdef CONFIG_RCU_TRACE
|
|
/* Read out queue lengths for tracing. */
|
|
static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
|
|
{
|
|
#ifdef CONFIG_RCU_NOCB_CPU
|
|
*ql = atomic_long_read(&rdp->nocb_q_count);
|
|
*qll = atomic_long_read(&rdp->nocb_q_count_lazy);
|
|
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
|
|
*ql = 0;
|
|
*qll = 0;
|
|
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
|
|
}
|
|
#endif /* #ifdef CONFIG_RCU_TRACE */
|