1 /* 2 * Read-Copy Update mechanism for mutual exclusion (tree-based version) 3 * Internal non-public definitions. 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, you can access it online at 17 * http://www.gnu.org/licenses/gpl-2.0.html. 18 * 19 * Copyright IBM Corporation, 2008 20 * 21 * Author: Ingo Molnar <mingo@elte.hu> 22 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> 23 */ 24 25 #include <linux/cache.h> 26 #include <linux/spinlock.h> 27 #include <linux/rtmutex.h> 28 #include <linux/threads.h> 29 #include <linux/cpumask.h> 30 #include <linux/seqlock.h> 31 #include <linux/swait.h> 32 #include <linux/stop_machine.h> 33 #include <linux/rcu_node_tree.h> 34 35 #include "rcu_segcblist.h" 36 37 /* 38 * Dynticks per-CPU state. 39 */ 40 struct rcu_dynticks { 41 long dynticks_nesting; /* Track process nesting level. */ 42 long dynticks_nmi_nesting; /* Track irq/NMI nesting level. */ 43 atomic_t dynticks; /* Even value for idle, else odd. */ 44 bool rcu_need_heavy_qs; /* GP old, need heavy quiescent state. */ 45 unsigned long rcu_qs_ctr; /* Light universal quiescent state ctr. */ 46 bool rcu_urgent_qs; /* GP old need light quiescent state. */ 47 #ifdef CONFIG_RCU_FAST_NO_HZ 48 bool all_lazy; /* Are all CPU's CBs lazy? */ 49 unsigned long nonlazy_posted; 50 /* # times non-lazy CBs posted to CPU. */ 51 unsigned long nonlazy_posted_snap; 52 /* idle-period nonlazy_posted snapshot. */ 53 unsigned long last_accelerate; 54 /* Last jiffy CBs were accelerated. */ 55 unsigned long last_advance_all; 56 /* Last jiffy CBs were all advanced. */ 57 int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */ 58 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ 59 }; 60 61 /* RCU's kthread states for tracing. */ 62 #define RCU_KTHREAD_STOPPED 0 63 #define RCU_KTHREAD_RUNNING 1 64 #define RCU_KTHREAD_WAITING 2 65 #define RCU_KTHREAD_OFFCPU 3 66 #define RCU_KTHREAD_YIELDING 4 67 #define RCU_KTHREAD_MAX 4 68 69 /* 70 * Definition for node within the RCU grace-period-detection hierarchy. 71 */ 72 struct rcu_node { 73 raw_spinlock_t __private lock; /* Root rcu_node's lock protects */ 74 /* some rcu_state fields as well as */ 75 /* following. */ 76 unsigned long gpnum; /* Current grace period for this node. */ 77 /* This will either be equal to or one */ 78 /* behind the root rcu_node's gpnum. */ 79 unsigned long completed; /* Last GP completed for this node. */ 80 /* This will either be equal to or one */ 81 /* behind the root rcu_node's gpnum. */ 82 unsigned long qsmask; /* CPUs or groups that need to switch in */ 83 /* order for current grace period to proceed.*/ 84 /* In leaf rcu_node, each bit corresponds to */ 85 /* an rcu_data structure, otherwise, each */ 86 /* bit corresponds to a child rcu_node */ 87 /* structure. */ 88 unsigned long qsmaskinit; 89 /* Per-GP initial value for qsmask. */ 90 /* Initialized from ->qsmaskinitnext at the */ 91 /* beginning of each grace period. */ 92 unsigned long qsmaskinitnext; 93 /* Online CPUs for next grace period. */ 94 unsigned long expmask; /* CPUs or groups that need to check in */ 95 /* to allow the current expedited GP */ 96 /* to complete. */ 97 unsigned long expmaskinit; 98 /* Per-GP initial values for expmask. */ 99 /* Initialized from ->expmaskinitnext at the */ 100 /* beginning of each expedited GP. */ 101 unsigned long expmaskinitnext; 102 /* Online CPUs for next expedited GP. */ 103 /* Any CPU that has ever been online will */ 104 /* have its bit set. */ 105 unsigned long ffmask; /* Fully functional CPUs. */ 106 unsigned long grpmask; /* Mask to apply to parent qsmask. */ 107 /* Only one bit will be set in this mask. */ 108 int grplo; /* lowest-numbered CPU or group here. */ 109 int grphi; /* highest-numbered CPU or group here. */ 110 u8 grpnum; /* CPU/group number for next level up. */ 111 u8 level; /* root is at level 0. */ 112 bool wait_blkd_tasks;/* Necessary to wait for blocked tasks to */ 113 /* exit RCU read-side critical sections */ 114 /* before propagating offline up the */ 115 /* rcu_node tree? */ 116 struct rcu_node *parent; 117 struct list_head blkd_tasks; 118 /* Tasks blocked in RCU read-side critical */ 119 /* section. Tasks are placed at the head */ 120 /* of this list and age towards the tail. */ 121 struct list_head *gp_tasks; 122 /* Pointer to the first task blocking the */ 123 /* current grace period, or NULL if there */ 124 /* is no such task. */ 125 struct list_head *exp_tasks; 126 /* Pointer to the first task blocking the */ 127 /* current expedited grace period, or NULL */ 128 /* if there is no such task. If there */ 129 /* is no current expedited grace period, */ 130 /* then there can cannot be any such task. */ 131 struct list_head *boost_tasks; 132 /* Pointer to first task that needs to be */ 133 /* priority boosted, or NULL if no priority */ 134 /* boosting is needed for this rcu_node */ 135 /* structure. If there are no tasks */ 136 /* queued on this rcu_node structure that */ 137 /* are blocking the current grace period, */ 138 /* there can be no such task. */ 139 struct rt_mutex boost_mtx; 140 /* Used only for the priority-boosting */ 141 /* side effect, not as a lock. */ 142 unsigned long boost_time; 143 /* When to start boosting (jiffies). */ 144 struct task_struct *boost_kthread_task; 145 /* kthread that takes care of priority */ 146 /* boosting for this rcu_node structure. */ 147 unsigned int boost_kthread_status; 148 /* State of boost_kthread_task for tracing. */ 149 unsigned long n_tasks_boosted; 150 /* Total number of tasks boosted. */ 151 unsigned long n_exp_boosts; 152 /* Number of tasks boosted for expedited GP. */ 153 unsigned long n_normal_boosts; 154 /* Number of tasks boosted for normal GP. */ 155 #ifdef CONFIG_RCU_NOCB_CPU 156 struct swait_queue_head nocb_gp_wq[2]; 157 /* Place for rcu_nocb_kthread() to wait GP. */ 158 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 159 int need_future_gp[2]; 160 /* Counts of upcoming no-CB GP requests. */ 161 raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp; 162 163 spinlock_t exp_lock ____cacheline_internodealigned_in_smp; 164 unsigned long exp_seq_rq; 165 wait_queue_head_t exp_wq[4]; 166 } ____cacheline_internodealigned_in_smp; 167 168 /* 169 * Bitmasks in an rcu_node cover the interval [grplo, grphi] of CPU IDs, and 170 * are indexed relative to this interval rather than the global CPU ID space. 171 * This generates the bit for a CPU in node-local masks. 172 */ 173 #define leaf_node_cpu_bit(rnp, cpu) (1UL << ((cpu) - (rnp)->grplo)) 174 175 /* 176 * Union to allow "aggregate OR" operation on the need for a quiescent 177 * state by the normal and expedited grace periods. 178 */ 179 union rcu_noqs { 180 struct { 181 u8 norm; 182 u8 exp; 183 } b; /* Bits. */ 184 u16 s; /* Set of bits, aggregate OR here. */ 185 }; 186 187 /* Index values for nxttail array in struct rcu_data. */ 188 #define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */ 189 #define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */ 190 #define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */ 191 #define RCU_NEXT_TAIL 3 192 #define RCU_NEXT_SIZE 4 193 194 /* Per-CPU data for read-copy update. */ 195 struct rcu_data { 196 /* 1) quiescent-state and grace-period handling : */ 197 unsigned long completed; /* Track rsp->completed gp number */ 198 /* in order to detect GP end. */ 199 unsigned long gpnum; /* Highest gp number that this CPU */ 200 /* is aware of having started. */ 201 unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */ 202 /* for rcu_all_qs() invocations. */ 203 union rcu_noqs cpu_no_qs; /* No QSes yet for this CPU. */ 204 bool core_needs_qs; /* Core waits for quiesc state. */ 205 bool beenonline; /* CPU online at least once. */ 206 bool gpwrap; /* Possible gpnum/completed wrap. */ 207 struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ 208 unsigned long grpmask; /* Mask to apply to leaf qsmask. */ 209 unsigned long ticks_this_gp; /* The number of scheduling-clock */ 210 /* ticks this CPU has handled */ 211 /* during and after the last grace */ 212 /* period it is aware of. */ 213 214 /* 2) batch handling */ 215 struct rcu_segcblist cblist; /* Segmented callback list, with */ 216 /* different callbacks waiting for */ 217 /* different grace periods. */ 218 long qlen_last_fqs_check; 219 /* qlen at last check for QS forcing */ 220 unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ 221 unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */ 222 unsigned long n_force_qs_snap; 223 /* did other CPU force QS recently? */ 224 long blimit; /* Upper limit on a processed batch */ 225 226 /* 3) dynticks interface. */ 227 struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ 228 int dynticks_snap; /* Per-GP tracking for dynticks. */ 229 230 /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ 231 unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */ 232 unsigned long offline_fqs; /* Kicked due to being offline. */ 233 unsigned long cond_resched_completed; 234 /* Grace period that needs help */ 235 /* from cond_resched(). */ 236 237 /* 5) __rcu_pending() statistics. */ 238 unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ 239 unsigned long n_rp_core_needs_qs; 240 unsigned long n_rp_report_qs; 241 unsigned long n_rp_cb_ready; 242 unsigned long n_rp_cpu_needs_gp; 243 unsigned long n_rp_gp_completed; 244 unsigned long n_rp_gp_started; 245 unsigned long n_rp_nocb_defer_wakeup; 246 unsigned long n_rp_need_nothing; 247 248 /* 6) _rcu_barrier(), OOM callbacks, and expediting. */ 249 struct rcu_head barrier_head; 250 #ifdef CONFIG_RCU_FAST_NO_HZ 251 struct rcu_head oom_head; 252 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ 253 atomic_long_t exp_workdone0; /* # done by workqueue. */ 254 atomic_long_t exp_workdone1; /* # done by others #1. */ 255 atomic_long_t exp_workdone2; /* # done by others #2. */ 256 atomic_long_t exp_workdone3; /* # done by others #3. */ 257 int exp_dynticks_snap; /* Double-check need for IPI. */ 258 259 /* 7) Callback offloading. */ 260 #ifdef CONFIG_RCU_NOCB_CPU 261 struct rcu_head *nocb_head; /* CBs waiting for kthread. */ 262 struct rcu_head **nocb_tail; 263 atomic_long_t nocb_q_count; /* # CBs waiting for nocb */ 264 atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */ 265 struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */ 266 struct rcu_head **nocb_follower_tail; 267 struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */ 268 struct task_struct *nocb_kthread; 269 raw_spinlock_t nocb_lock; /* Guard following pair of fields. */ 270 int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ 271 struct timer_list nocb_timer; /* Enforce finite deferral. */ 272 273 /* The following fields are used by the leader, hence own cacheline. */ 274 struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; 275 /* CBs waiting for GP. */ 276 struct rcu_head **nocb_gp_tail; 277 bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */ 278 struct rcu_data *nocb_next_follower; 279 /* Next follower in wakeup chain. */ 280 281 /* The following fields are used by the follower, hence new cachline. */ 282 struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp; 283 /* Leader CPU takes GP-end wakeups. */ 284 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 285 286 /* 8) RCU CPU stall data. */ 287 unsigned int softirq_snap; /* Snapshot of softirq activity. */ 288 /* ->rcu_iw* fields protected by leaf rcu_node ->lock. */ 289 struct irq_work rcu_iw; /* Check for non-irq activity. */ 290 bool rcu_iw_pending; /* Is ->rcu_iw pending? */ 291 unsigned long rcu_iw_gpnum; /* ->gpnum associated with ->rcu_iw. */ 292 293 int cpu; 294 struct rcu_state *rsp; 295 }; 296 297 /* Values for nocb_defer_wakeup field in struct rcu_data. */ 298 #define RCU_NOCB_WAKE_NOT 0 299 #define RCU_NOCB_WAKE 1 300 #define RCU_NOCB_WAKE_FORCE 2 301 302 #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500)) 303 /* For jiffies_till_first_fqs and */ 304 /* and jiffies_till_next_fqs. */ 305 306 #define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */ 307 /* delay between bouts of */ 308 /* quiescent-state forcing. */ 309 310 #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */ 311 /* at least one scheduling clock */ 312 /* irq before ratting on them. */ 313 314 #define rcu_wait(cond) \ 315 do { \ 316 for (;;) { \ 317 set_current_state(TASK_INTERRUPTIBLE); \ 318 if (cond) \ 319 break; \ 320 schedule(); \ 321 } \ 322 __set_current_state(TASK_RUNNING); \ 323 } while (0) 324 325 /* 326 * RCU global state, including node hierarchy. This hierarchy is 327 * represented in "heap" form in a dense array. The root (first level) 328 * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second 329 * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), 330 * and the third level in ->node[m+1] and following (->node[m+1] referenced 331 * by ->level[2]). The number of levels is determined by the number of 332 * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" 333 * consisting of a single rcu_node. 334 */ 335 struct rcu_state { 336 struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ 337 struct rcu_node *level[RCU_NUM_LVLS + 1]; 338 /* Hierarchy levels (+1 to */ 339 /* shut bogus gcc warning) */ 340 struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ 341 call_rcu_func_t call; /* call_rcu() flavor. */ 342 int ncpus; /* # CPUs seen so far. */ 343 344 /* The following fields are guarded by the root rcu_node's lock. */ 345 346 u8 boost ____cacheline_internodealigned_in_smp; 347 /* Subject to priority boost. */ 348 unsigned long gpnum; /* Current gp number. */ 349 unsigned long completed; /* # of last completed gp. */ 350 struct task_struct *gp_kthread; /* Task for grace periods. */ 351 struct swait_queue_head gp_wq; /* Where GP task waits. */ 352 short gp_flags; /* Commands for GP task. */ 353 short gp_state; /* GP kthread sleep state. */ 354 355 /* End of fields guarded by root rcu_node's lock. */ 356 357 struct mutex barrier_mutex; /* Guards barrier fields. */ 358 atomic_t barrier_cpu_count; /* # CPUs waiting on. */ 359 struct completion barrier_completion; /* Wake at barrier end. */ 360 unsigned long barrier_sequence; /* ++ at start and end of */ 361 /* _rcu_barrier(). */ 362 /* End of fields guarded by barrier_mutex. */ 363 364 struct mutex exp_mutex; /* Serialize expedited GP. */ 365 struct mutex exp_wake_mutex; /* Serialize wakeup. */ 366 unsigned long expedited_sequence; /* Take a ticket. */ 367 atomic_t expedited_need_qs; /* # CPUs left to check in. */ 368 struct swait_queue_head expedited_wq; /* Wait for check-ins. */ 369 int ncpus_snap; /* # CPUs seen last time. */ 370 371 unsigned long jiffies_force_qs; /* Time at which to invoke */ 372 /* force_quiescent_state(). */ 373 unsigned long jiffies_kick_kthreads; /* Time at which to kick */ 374 /* kthreads, if configured. */ 375 unsigned long n_force_qs; /* Number of calls to */ 376 /* force_quiescent_state(). */ 377 unsigned long n_force_qs_lh; /* ~Number of calls leaving */ 378 /* due to lock unavailable. */ 379 unsigned long n_force_qs_ngp; /* Number of calls leaving */ 380 /* due to no GP active. */ 381 unsigned long gp_start; /* Time at which GP started, */ 382 /* but in jiffies. */ 383 unsigned long gp_activity; /* Time of last GP kthread */ 384 /* activity in jiffies. */ 385 unsigned long jiffies_stall; /* Time at which to check */ 386 /* for CPU stalls. */ 387 unsigned long jiffies_resched; /* Time at which to resched */ 388 /* a reluctant CPU. */ 389 unsigned long n_force_qs_gpstart; /* Snapshot of n_force_qs at */ 390 /* GP start. */ 391 unsigned long gp_max; /* Maximum GP duration in */ 392 /* jiffies. */ 393 const char *name; /* Name of structure. */ 394 char abbr; /* Abbreviated name. */ 395 struct list_head flavors; /* List of RCU flavors. */ 396 }; 397 398 /* Values for rcu_state structure's gp_flags field. */ 399 #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ 400 #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ 401 402 /* Values for rcu_state structure's gp_state field. */ 403 #define RCU_GP_IDLE 0 /* Initial state and no GP in progress. */ 404 #define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */ 405 #define RCU_GP_DONE_GPS 2 /* Wait done for grace-period start. */ 406 #define RCU_GP_WAIT_FQS 3 /* Wait for force-quiescent-state time. */ 407 #define RCU_GP_DOING_FQS 4 /* Wait done for force-quiescent-state time. */ 408 #define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */ 409 #define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */ 410 411 #ifndef RCU_TREE_NONCORE 412 static const char * const gp_state_names[] = { 413 "RCU_GP_IDLE", 414 "RCU_GP_WAIT_GPS", 415 "RCU_GP_DONE_GPS", 416 "RCU_GP_WAIT_FQS", 417 "RCU_GP_DOING_FQS", 418 "RCU_GP_CLEANUP", 419 "RCU_GP_CLEANED", 420 }; 421 #endif /* #ifndef RCU_TREE_NONCORE */ 422 423 extern struct list_head rcu_struct_flavors; 424 425 /* Sequence through rcu_state structures for each RCU flavor. */ 426 #define for_each_rcu_flavor(rsp) \ 427 list_for_each_entry((rsp), &rcu_struct_flavors, flavors) 428 429 /* 430 * RCU implementation internal declarations: 431 */ 432 extern struct rcu_state rcu_sched_state; 433 434 extern struct rcu_state rcu_bh_state; 435 436 #ifdef CONFIG_PREEMPT_RCU 437 extern struct rcu_state rcu_preempt_state; 438 #endif /* #ifdef CONFIG_PREEMPT_RCU */ 439 440 int rcu_dynticks_snap(struct rcu_dynticks *rdtp); 441 bool rcu_eqs_special_set(int cpu); 442 443 #ifdef CONFIG_RCU_BOOST 444 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); 445 DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); 446 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); 447 DECLARE_PER_CPU(char, rcu_cpu_has_work); 448 #endif /* #ifdef CONFIG_RCU_BOOST */ 449 450 #ifndef RCU_TREE_NONCORE 451 452 /* Forward declarations for rcutree_plugin.h */ 453 static void rcu_bootup_announce(void); 454 static void rcu_preempt_note_context_switch(bool preempt); 455 static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); 456 #ifdef CONFIG_HOTPLUG_CPU 457 static bool rcu_preempt_has_tasks(struct rcu_node *rnp); 458 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 459 static void rcu_print_detail_task_stall(struct rcu_state *rsp); 460 static int rcu_print_task_stall(struct rcu_node *rnp); 461 static int rcu_print_task_exp_stall(struct rcu_node *rnp); 462 static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); 463 static void rcu_preempt_check_callbacks(void); 464 void call_rcu(struct rcu_head *head, rcu_callback_t func); 465 static void __init __rcu_init_preempt(void); 466 static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); 467 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); 468 static void invoke_rcu_callbacks_kthread(void); 469 static bool rcu_is_callbacks_kthread(void); 470 #ifdef CONFIG_RCU_BOOST 471 static void rcu_preempt_do_callbacks(void); 472 static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, 473 struct rcu_node *rnp); 474 #endif /* #ifdef CONFIG_RCU_BOOST */ 475 static void __init rcu_spawn_boost_kthreads(void); 476 static void rcu_prepare_kthreads(int cpu); 477 static void rcu_cleanup_after_idle(void); 478 static void rcu_prepare_for_idle(void); 479 static void rcu_idle_count_callbacks_posted(void); 480 static bool rcu_preempt_has_tasks(struct rcu_node *rnp); 481 static void print_cpu_stall_info_begin(void); 482 static void print_cpu_stall_info(struct rcu_state *rsp, int cpu); 483 static void print_cpu_stall_info_end(void); 484 static void zero_cpu_stall_ticks(struct rcu_data *rdp); 485 static void increment_cpu_stall_ticks(void); 486 static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu); 487 static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq); 488 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp); 489 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq); 490 static void rcu_init_one_nocb(struct rcu_node *rnp); 491 static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, 492 bool lazy, unsigned long flags); 493 static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp, 494 struct rcu_data *rdp, 495 unsigned long flags); 496 static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); 497 static void do_nocb_deferred_wakeup(struct rcu_data *rdp); 498 static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); 499 static void rcu_spawn_all_nocb_kthreads(int cpu); 500 static void __init rcu_spawn_nocb_kthreads(void); 501 #ifdef CONFIG_RCU_NOCB_CPU 502 static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp); 503 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 504 static void __maybe_unused rcu_kick_nohz_cpu(int cpu); 505 static bool init_nocb_callback_list(struct rcu_data *rdp); 506 static void rcu_bind_gp_kthread(void); 507 static bool rcu_nohz_full_cpu(struct rcu_state *rsp); 508 static void rcu_dynticks_task_enter(void); 509 static void rcu_dynticks_task_exit(void); 510 511 #ifdef CONFIG_SRCU 512 void srcu_online_cpu(unsigned int cpu); 513 void srcu_offline_cpu(unsigned int cpu); 514 #else /* #ifdef CONFIG_SRCU */ 515 void srcu_online_cpu(unsigned int cpu) { } 516 void srcu_offline_cpu(unsigned int cpu) { } 517 #endif /* #else #ifdef CONFIG_SRCU */ 518 519 #endif /* #ifndef RCU_TREE_NONCORE */ 520