0 "lm_J*j"Troh*bѿ hMAJOR=4 MINOR=8 DEVNAME=tty8 A l4( (  fB- u9_I|+am_J*j"TvF /* SPDX-License-Identifier: GPL-2.0+ */ /* * Sleepable Read-Copy Update mechanism for mutual exclusion, * tree variant. * * Copyright (C) IBM Corporation, 2017 * * Author: Paul McKenney */ #ifndef _LINUX_SRCU_TREE_H #define _LINUX_SRCU_TREE_H #include #include struct srcu_node; struct srcu_struct; /* * Per-CPU structure feeding into leaf srcu_node, similar in function * to rcu_node. */ struct srcu_data { /* Read-side state. */ atomic_long_t srcu_lock_count[2]; /* Locks per CPU. */ atomic_long_t srcu_unlock_count[2]; /* Unlocks per CPU. */ int srcu_nmi_safety; /* NMI-safe srcu_struct structure? */ /* Update-side state. */ spinlock_t __private lock ____cacheline_internodealigned_in_smp; struct rcu_segcblist srcu_cblist; /* List of callbacks.*/ unsigned long srcu_gp_seq_needed; /* Furthest future GP needed. */ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ bool srcu_cblist_invoking; /* Invoking these CBs? */ struct timer_list delay_work; /* Delay for CB invoking */ struct work_struct work; /* Context for CB invoking. */ struct rcu_head srcu_barrier_head; /* For srcu_barrier() use. */ struct srcu_node *mynode; /* Leaf srcu_node. */ unsigned long grpmask; /* Mask for leaf srcu_node */ /* ->srcu_data_have_cbs[]. */ int cpu; struct srcu_struct *ssp; }; /* * Node in SRCU combining tree, similar in function to rcu_data. */ struct srcu_node { spinlock_t __private lock; unsigned long srcu_have_cbs[4]; /* GP seq for children having CBs, but only */ /* if greater than ->srcu_gq_seq. */ unsigned long srcu_data_have_cbs[4]; /* Which srcu_data structs have CBs for given GP? */ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ struct srcu_node *srcu_parent; /* Next up in tree. */ int grplo; /* Least CPU for node. */ int grphi; /* Biggest CPU for node. */ }; /* * Per-SRCU-domain structure, update-side data linked from srcu_struct. */ struct srcu_usage { struct srcu_node *node; /* Combining tree. */ struct srcu_node *level[RCU_NUM_LVLS + 1]; /* First node at each level. */ int srcu_size_state; /* Small-to-big transition state. */ struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ spinlock_t __private lock; /* Protect counters and size state. */ struct mutex srcu_gp_mutex; /* Serialize GP work. */ unsigned long srcu_gp_seq; /* Grace-period seq #. */ unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ unsigned long srcu_gp_start; /* Last GP start timestamp (jiffies) */ unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */ unsigned long srcu_size_jiffies; /* Current contention-measurement interval. */ unsigned long srcu_n_lock_retries; /* Contention events in current interval. */ unsigned long srcu_n_exp_nodelay; /* # expedited no-delays in current GP phase. */ bool sda_is_static; /* May ->sda be passed to free_percpu()? */ unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */ struct mutex srcu_barrier_mutex; /* Serialize barrier ops. */ struct completion srcu_barrier_completion; /* Awaken barrier rq at end. */ atomic_t srcu_barrier_cpu_cnt; /* # CPUs not yet posting a */ /* callback for the barrier */ /* operation. */ unsigned long reschedule_jiffies; unsigned long reschedule_count; struct delayed_work work; struct srcu_struct *srcu_ssp; }; /* * Per-SRCU-domain structure, similar in function to rcu_state. */ struct srcu_struct { unsigned int srcu_idx; /* Current rdr array element. */ struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */ struct lockdep_map dep_map; struct srcu_usage *srcu_sup; /* Update-side data. */ }; /* Values for size state variable (->srcu_size_state). */ #define SRCU_SIZE_SMALL 0 #define SRCU_S