diff options
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 340 |
1 files changed, 208 insertions, 132 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index d90b02b53c0e..b8bbe7960cda 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -1,44 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ /* * Read-Copy Update mechanism for mutual exclusion (tree-based version) * Internal non-public definitions. * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, you can access it online at - * http://www.gnu.org/licenses/gpl-2.0.html. - * * Copyright IBM Corporation, 2008 * * Author: Ingo Molnar <mingo@elte.hu> - * Paul E. McKenney <paulmck@linux.vnet.ibm.com> + * Paul E. McKenney <paulmck@linux.ibm.com> */ #include <linux/cache.h> +#include <linux/kthread.h> #include <linux/spinlock.h> #include <linux/rtmutex.h> #include <linux/threads.h> #include <linux/cpumask.h> #include <linux/seqlock.h> #include <linux/swait.h> -#include <linux/stop_machine.h> #include <linux/rcu_node_tree.h> #include "rcu_segcblist.h" -/* Communicate arguments to a workqueue handler. */ +/* Communicate arguments to a kthread worker handler. */ struct rcu_exp_work { - smp_call_func_t rew_func; unsigned long rew_s; - struct work_struct rew_work; + struct kthread_work rew_work; }; /* RCU's kthread states for tracing. */ @@ -56,7 +42,7 @@ struct rcu_node { raw_spinlock_t __private lock; /* Root rcu_node's lock protects */ /* some rcu_state fields as well as */ /* following. */ - unsigned long gp_seq; /* Track rsp->rcu_gp_seq. */ + unsigned long gp_seq; /* Track rsp->gp_seq. */ unsigned long gp_seq_needed; /* Track furthest future GP request. */ unsigned long completedqs; /* All QSes done for this node. */ unsigned long qsmask; /* CPUs or groups that need to switch in */ @@ -71,7 +57,6 @@ struct rcu_node { /* Initialized from ->qsmaskinitnext at the */ /* beginning of each grace period. */ unsigned long qsmaskinitnext; - /* Online CPUs for next grace period. */ unsigned long expmask; /* CPUs or groups that need to check in */ /* to allow the current expedited GP */ /* to complete. */ @@ -83,12 +68,17 @@ struct rcu_node { /* Online CPUs for next expedited GP. */ /* Any CPU that has ever been online will */ /* have its bit set. */ + struct kthread_worker *exp_kworker; + /* Workers performing per node expedited GP */ + /* initialization. */ + unsigned long cbovldmask; + /* CPUs experiencing callback overload. */ unsigned long ffmask; /* Fully functional CPUs. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ /* Only one bit will be set in this mask. */ - int grplo; /* lowest-numbered CPU or group here. */ - int grphi; /* highest-numbered CPU or group here. */ - u8 grpnum; /* CPU/group number for next level up. */ + int grplo; /* lowest-numbered CPU here. */ + int grphi; /* highest-numbered CPU here. */ + u8 grpnum; /* group number for next level up. */ u8 level; /* root is at level 0. */ bool wait_blkd_tasks;/* Necessary to wait for blocked tasks to */ /* exit RCU read-side critical sections */ @@ -122,11 +112,15 @@ struct rcu_node { /* side effect, not as a lock. */ unsigned long boost_time; /* When to start boosting (jiffies). */ + struct mutex kthread_mutex; + /* Exclusion for thread spawning and affinity */ + /* manipulation. */ struct task_struct *boost_kthread_task; /* kthread that takes care of priority */ /* boosting for this rcu_node structure. */ unsigned int boost_kthread_status; /* State of boost_kthread_task for tracing. */ + unsigned long n_boosts; /* Number of boosts for this rcu_node structure. */ #ifdef CONFIG_RCU_NOCB_CPU struct swait_queue_head nocb_gp_wq[2]; /* Place for rcu_nocb_kthread() to wait GP. */ @@ -138,6 +132,10 @@ struct rcu_node { wait_queue_head_t exp_wq[4]; struct rcu_exp_work rew; bool exp_need_flush; /* Need to flush workitem? */ + raw_spinlock_t exp_poll_lock; + /* Lock and data for polled expedited grace periods. */ + unsigned long exp_seq_poll_rq; + struct work_struct exp_poll_wq; } ____cacheline_internodealigned_in_smp; /* @@ -159,22 +157,54 @@ union rcu_noqs { u16 s; /* Set of bits, aggregate OR here. */ }; +/* + * Record the snapshot of the core stats at half of the first RCU stall timeout. + * The member gp_seq is used to ensure that all members are updated only once + * during the sampling period. The snapshot is taken only if this gp_seq is not + * equal to rdp->gp_seq. + */ +struct rcu_snap_record { + unsigned long gp_seq; /* Track rdp->gp_seq counter */ + u64 cputime_irq; /* Accumulated cputime of hard irqs */ + u64 cputime_softirq;/* Accumulated cputime of soft irqs */ + u64 cputime_system; /* Accumulated cputime of kernel tasks */ + u64 nr_hardirqs; /* Accumulated number of hard irqs */ + unsigned int nr_softirqs; /* Accumulated number of soft irqs */ + unsigned long long nr_csw; /* Accumulated number of task switches */ + unsigned long jiffies; /* Track jiffies value */ +}; + +/* + * An IRQ work (deferred_qs_iw) is used by RCU to get the scheduler's attention. + * to report quiescent states at the soonest possible time. + * The request can be in one of the following states: + * - DEFER_QS_IDLE: An IRQ work is yet to be scheduled. + * - DEFER_QS_PENDING: An IRQ work was scheduled but either not yet run, or it + * ran and we still haven't reported a quiescent state. + */ +#define DEFER_QS_IDLE 0 +#define DEFER_QS_PENDING 1 + /* Per-CPU data for read-copy update. */ struct rcu_data { /* 1) quiescent-state and grace-period handling : */ - unsigned long gp_seq; /* Track rsp->rcu_gp_seq counter. */ + unsigned long gp_seq; /* Track rsp->gp_seq counter. */ unsigned long gp_seq_needed; /* Track furthest future GP request. */ union rcu_noqs cpu_no_qs; /* No QSes yet for this CPU. */ - bool core_needs_qs; /* Core waits for quiesc state. */ + bool core_needs_qs; /* Core waits for quiescent state. */ bool beenonline; /* CPU online at least once. */ bool gpwrap; /* Possible ->gp_seq wrap. */ - bool deferred_qs; /* This CPU awaiting a deferred QS? */ + unsigned int gpwrap_count; /* Count of GP sequence wrap. */ + bool cpu_started; /* RCU watching this onlining CPU. */ struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ unsigned long grpmask; /* Mask to apply to leaf qsmask. */ unsigned long ticks_this_gp; /* The number of scheduling-clock */ /* ticks this CPU has handled */ /* during and after the last grace */ /* period it is aware of. */ + struct irq_work defer_qs_iw; /* Obtain later scheduler attention. */ + int defer_qs_iw_pending; /* Scheduler attention pending? */ + struct work_struct strict_work; /* Schedule readers for strict GPs. */ /* 2) batch handling */ struct rcu_segcblist cblist; /* Segmented callback list, with */ @@ -182,77 +212,96 @@ struct rcu_data { /* different grace periods. */ long qlen_last_fqs_check; /* qlen at last check for QS forcing */ + unsigned long n_cbs_invoked; /* # callbacks invoked since boot. */ unsigned long n_force_qs_snap; /* did other CPU force QS recently? */ long blimit; /* Upper limit on a processed batch */ /* 3) dynticks interface. */ - int dynticks_snap; /* Per-GP tracking for dynticks. */ - long dynticks_nesting; /* Track process nesting level. */ - long dynticks_nmi_nesting; /* Track irq/NMI nesting level. */ - atomic_t dynticks; /* Even value for idle, else odd. */ + int watching_snap; /* Per-GP tracking for dynticks. */ bool rcu_need_heavy_qs; /* GP old, so heavy quiescent state! */ bool rcu_urgent_qs; /* GP old need light quiescent state. */ -#ifdef CONFIG_RCU_FAST_NO_HZ - bool all_lazy; /* Are all CPU's CBs lazy? */ - unsigned long nonlazy_posted; /* # times non-lazy CB posted to CPU. */ - unsigned long nonlazy_posted_snap; - /* Nonlazy_posted snapshot. */ - unsigned long last_accelerate; /* Last jiffy CBs were accelerated. */ - unsigned long last_advance_all; /* Last jiffy CBs were all advanced. */ - int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */ -#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ + bool rcu_forced_tick; /* Forced tick to provide QS. */ + bool rcu_forced_tick_exp; /* ... provide QS to expedited GP. */ /* 4) rcu_barrier(), OOM callbacks, and expediting. */ + unsigned long barrier_seq_snap; /* Snap of rcu_state.barrier_sequence. */ struct rcu_head barrier_head; - int exp_dynticks_snap; /* Double-check need for IPI. */ + int exp_watching_snap; /* Double-check need for IPI. */ /* 5) Callback offloading. */ #ifdef CONFIG_RCU_NOCB_CPU - struct rcu_head *nocb_head; /* CBs waiting for kthread. */ - struct rcu_head **nocb_tail; - atomic_long_t nocb_q_count; /* # CBs waiting for nocb */ - atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */ - struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */ - struct rcu_head **nocb_follower_tail; - struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */ - struct task_struct *nocb_kthread; + struct swait_queue_head nocb_cb_wq; /* For nocb kthreads to sleep on. */ + struct swait_queue_head nocb_state_wq; /* For offloading state changes */ + struct task_struct *nocb_gp_kthread; raw_spinlock_t nocb_lock; /* Guard following pair of fields. */ int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ struct timer_list nocb_timer; /* Enforce finite deferral. */ - - /* The following fields are used by the leader, hence own cacheline. */ - struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; - /* CBs waiting for GP. */ - struct rcu_head **nocb_gp_tail; - bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */ - struct rcu_data *nocb_next_follower; - /* Next follower in wakeup chain. */ - - /* The following fields are used by the follower, hence new cachline. */ - struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp; - /* Leader CPU takes GP-end wakeups. */ + unsigned long nocb_gp_adv_time; /* Last call_rcu() CB adv (jiffies). */ + struct mutex nocb_gp_kthread_mutex; /* Exclusion for nocb gp kthread */ + /* spawning */ + + /* The following fields are used by call_rcu, hence own cacheline. */ + raw_spinlock_t nocb_bypass_lock ____cacheline_internodealigned_in_smp; + struct rcu_cblist nocb_bypass; /* Lock-contention-bypass CB list. */ + unsigned long nocb_bypass_first; /* Time (jiffies) of first enqueue. */ + unsigned long nocb_nobypass_last; /* Last ->cblist enqueue (jiffies). */ + int nocb_nobypass_count; /* # ->cblist enqueues at ^^^ time. */ + + /* The following fields are used by GP kthread, hence own cacheline. */ + raw_spinlock_t nocb_gp_lock ____cacheline_internodealigned_in_smp; + u8 nocb_gp_sleep; /* Is the nocb GP thread asleep? */ + u8 nocb_gp_bypass; /* Found a bypass on last scan? */ + u8 nocb_gp_gp; /* GP to wait for on last scan? */ + unsigned long nocb_gp_seq; /* If so, ->gp_seq to wait for. */ + unsigned long nocb_gp_loops; /* # passes through wait code. */ + struct swait_queue_head nocb_gp_wq; /* For nocb kthreads to sleep on. */ + bool nocb_cb_sleep; /* Is the nocb CB thread asleep? */ + struct task_struct *nocb_cb_kthread; + struct list_head nocb_head_rdp; /* + * Head of rcu_data list in wakeup chain, + * if rdp_gp. + */ + struct list_head nocb_entry_rdp; /* rcu_data node in wakeup chain. */ + struct rcu_data *nocb_toggling_rdp; /* rdp queued for (de-)offloading */ + + /* The following fields are used by CB kthread, hence new cacheline. */ + struct rcu_data *nocb_gp_rdp ____cacheline_internodealigned_in_smp; + /* GP rdp takes GP-end wakeups. */ #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ - /* 6) Diagnostic data, including RCU CPU stall warnings. */ + /* 6) RCU priority boosting. */ + struct task_struct *rcu_cpu_kthread_task; + /* rcuc per-CPU kthread or NULL. */ + unsigned int rcu_cpu_kthread_status; + char rcu_cpu_has_work; + unsigned long rcuc_activity; + + /* 7) Diagnostic data, including RCU CPU stall warnings. */ unsigned int softirq_snap; /* Snapshot of softirq activity. */ /* ->rcu_iw* fields protected by leaf rcu_node ->lock. */ struct irq_work rcu_iw; /* Check for non-irq activity. */ bool rcu_iw_pending; /* Is ->rcu_iw pending? */ unsigned long rcu_iw_gp_seq; /* ->gp_seq associated with ->rcu_iw. */ unsigned long rcu_ofl_gp_seq; /* ->gp_seq at last offline. */ - short rcu_ofl_gp_flags; /* ->gp_flags at last offline. */ + short rcu_ofl_gp_state; /* ->gp_state at last offline. */ unsigned long rcu_onl_gp_seq; /* ->gp_seq at last online. */ - short rcu_onl_gp_flags; /* ->gp_flags at last online. */ + short rcu_onl_gp_state; /* ->gp_state at last online. */ unsigned long last_fqs_resched; /* Time of last rcu_resched(). */ + unsigned long last_sched_clock; /* Jiffies of last rcu_sched_clock_irq(). */ + struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */ + /* the first RCU stall timeout */ + long lazy_len; /* Length of buffered lazy callbacks. */ int cpu; }; /* Values for nocb_defer_wakeup field in struct rcu_data. */ #define RCU_NOCB_WAKE_NOT 0 -#define RCU_NOCB_WAKE 1 -#define RCU_NOCB_WAKE_FORCE 2 +#define RCU_NOCB_WAKE_BYPASS 1 +#define RCU_NOCB_WAKE_LAZY 2 +#define RCU_NOCB_WAKE 3 +#define RCU_NOCB_WAKE_FORCE 4 #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500)) /* For jiffies_till_first_fqs and */ @@ -278,6 +327,19 @@ do { \ } while (0) /* + * A max threshold for synchronize_rcu() users which are + * awaken directly by the rcu_gp_kthread(). Left part is + * deferred to the main worker. + */ +#define SR_MAX_USERS_WAKE_FROM_GP 5 +#define SR_NORMAL_GP_WAIT_HEAD_MAX 5 + +struct sr_wait_node { + atomic_t inuse; + struct llist_node node; +}; + +/* * 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 @@ -293,16 +355,23 @@ struct rcu_state { /* Hierarchy levels (+1 to */ /* shut bogus gcc warning) */ int ncpus; /* # CPUs seen so far. */ + int n_online_cpus; /* # CPUs online for RCU. */ /* The following fields are guarded by the root rcu_node's lock. */ - u8 boost ____cacheline_internodealigned_in_smp; - /* Subject to priority boost. */ - unsigned long gp_seq; /* Grace-period sequence #. */ + unsigned long gp_seq ____cacheline_internodealigned_in_smp; + /* Grace-period sequence #. */ + unsigned long gp_max; /* Maximum GP duration in */ + /* jiffies. */ struct task_struct *gp_kthread; /* Task for grace periods. */ struct swait_queue_head gp_wq; /* Where GP task waits. */ short gp_flags; /* Commands for GP task. */ short gp_state; /* GP kthread sleep state. */ + unsigned long gp_wake_time; /* Last GP kthread wake. */ + unsigned long gp_wake_seq; /* ->gp_seq at ^^^. */ + unsigned long gp_seq_polled; /* GP seq for polled API. */ + unsigned long gp_seq_polled_snap; /* ->gp_seq_polled at normal GP start. */ + unsigned long gp_seq_polled_exp_snap; /* ->gp_seq_polled at expedited GP start. */ /* End of fields guarded by root rcu_node's lock. */ @@ -313,12 +382,16 @@ struct rcu_state { /* rcu_barrier(). */ /* End of fields guarded by barrier_mutex. */ + raw_spinlock_t barrier_lock; /* Protects ->barrier_seq_snap. */ + struct mutex exp_mutex; /* Serialize expedited GP. */ struct mutex exp_wake_mutex; /* Serialize wakeup. */ unsigned long expedited_sequence; /* Take a ticket. */ atomic_t expedited_need_qs; /* # CPUs left to check in. */ struct swait_queue_head expedited_wq; /* Wait for check-ins. */ int ncpus_snap; /* # CPUs seen last time. */ + u8 cbovld; /* Callback overload now? */ + u8 cbovldnext; /* ^ ^ next time? */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */ @@ -336,23 +409,39 @@ struct rcu_state { /* in jiffies. */ unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ + int nr_fqs_jiffies_stall; /* Number of fqs loops after + * which read jiffies and set + * jiffies_stall. Stall + * warnings disabled if !0. */ 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. */ - raw_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp; + arch_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp; /* Synchronize offline with */ /* GP pre-initialization. */ + + /* synchronize_rcu() part. */ + struct llist_head srs_next; /* request a GP users. */ + struct llist_node *srs_wait_tail; /* wait for GP users. */ + struct llist_node *srs_done_tail; /* ready for GP users. */ + struct sr_wait_node srs_wait_nodes[SR_NORMAL_GP_WAIT_HEAD_MAX]; + struct work_struct srs_cleanup_work; + atomic_t srs_cleanups_pending; /* srs inflight worker cleanups. */ + +#ifdef CONFIG_RCU_NOCB_CPU + struct mutex nocb_mutex; /* Guards (de-)offloading */ + int nocb_is_setup; /* nocb is setup from boot */ +#endif }; /* 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. */ +#define RCU_GP_FLAG_OVLD 0x4 /* Experiencing callback overload. */ /* Values for rcu_state structure's gp_state field. */ #define RCU_GP_IDLE 0 /* Initial state and no GP in progress. */ @@ -365,18 +454,6 @@ struct rcu_state { #define RCU_GP_CLEANUP 7 /* Grace-period cleanup started. */ #define RCU_GP_CLEANED 8 /* Grace-period cleanup complete. */ -static const char * const gp_state_names[] = { - "RCU_GP_IDLE", - "RCU_GP_WAIT_GPS", - "RCU_GP_DONE_GPS", - "RCU_GP_ONOFF", - "RCU_GP_INIT", - "RCU_GP_WAIT_FQS", - "RCU_GP_DOING_FQS", - "RCU_GP_CLEANUP", - "RCU_GP_CLEANED", -}; - /* * In order to export the rcu_state name to the tracing tools, it * needs to be added in the __tracepoint_string section. @@ -400,73 +477,72 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name; #define RCU_NAME rcu_name #endif /* #else #ifdef CONFIG_TRACING */ -int rcu_dynticks_snap(struct rcu_data *rdp); - -#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 */ - -/* Forward declarations for rcutree_plugin.h */ +/* Forward declarations for tree_plugin.h */ static void rcu_bootup_announce(void); static void rcu_qs(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(void); -static int rcu_print_task_stall(struct rcu_node *rnp); static int rcu_print_task_exp_stall(struct rcu_node *rnp); static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); -static void rcu_flavor_check_callbacks(int user); -void call_rcu(struct rcu_head *head, rcu_callback_t func); +static void rcu_flavor_sched_clock_irq(int user); static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck); +static void rcu_preempt_deferred_qs_init(struct rcu_data *rdp); 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); -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_is_callbacks_kthread(struct rcu_data *rdp); +static void rcu_cpu_kthread_setup(unsigned int cpu); +static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp); static bool rcu_preempt_has_tasks(struct rcu_node *rnp); static bool rcu_preempt_need_deferred_qs(struct task_struct *t); -static void rcu_preempt_deferred_qs(struct task_struct *t); -static void print_cpu_stall_info_begin(void); -static void print_cpu_stall_info(int cpu); -static void print_cpu_stall_info_end(void); static void zero_cpu_stall_ticks(struct rcu_data *rdp); -static bool rcu_nocb_cpu_needs_barrier(int cpu); static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp); static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq); 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_data *my_rdp, - 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 bool wake_nocb_gp(struct rcu_data *rdp, bool force); +static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp, + unsigned long j, bool lazy); +static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head, + rcu_callback_t func, unsigned long flags, bool lazy); +static void __maybe_unused __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty, + unsigned long flags); +static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level); +static bool 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); +static void rcu_spawn_cpu_nocb_kthread(int cpu); +static void show_rcu_nocb_state(struct rcu_data *rdp); +static void rcu_nocb_lock(struct rcu_data *rdp); +static void rcu_nocb_unlock(struct rcu_data *rdp); +static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp, + unsigned long flags); +static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp); #ifdef CONFIG_RCU_NOCB_CPU static void __init rcu_organize_nocb_kthreads(void); -#endif /* #ifdef CONFIG_RCU_NOCB_CPU */ -static bool init_nocb_callback_list(struct rcu_data *rdp); -static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp); + +/* + * Disable IRQs before checking offloaded state so that local + * locking is safe against concurrent de-offloading. + */ +#define rcu_nocb_lock_irqsave(rdp, flags) \ +do { \ + local_irq_save(flags); \ + if (rcu_segcblist_is_offloaded(&(rdp)->cblist)) \ + raw_spin_lock(&(rdp)->nocb_lock); \ +} while (0) +#else /* #ifdef CONFIG_RCU_NOCB_CPU */ +#define rcu_nocb_lock_irqsave(rdp, flags) local_irq_save(flags) +#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ + static void rcu_bind_gp_kthread(void); static bool rcu_nohz_full_cpu(void); -static void rcu_dynticks_task_enter(void); -static void rcu_dynticks_task_exit(void); - -#ifdef CONFIG_SRCU -void srcu_online_cpu(unsigned int cpu); -void srcu_offline_cpu(unsigned int cpu); -#else /* #ifdef CONFIG_SRCU */ -void srcu_online_cpu(unsigned int cpu) { } -void srcu_offline_cpu(unsigned int cpu) { } -#endif /* #else #ifdef CONFIG_SRCU */ + +/* Forward declarations for tree_stall.h */ +static void record_gp_stall_check_time(void); +static void rcu_iw_handler(struct irq_work *iwp); +static void check_cpu_stall(struct rcu_data *rdp); +static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp, + const unsigned long gpssdelay); + +/* Forward declarations for tree_exp.h. */ +static void sync_rcu_do_polled_gp(struct work_struct *wp); |