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 long dynticks_nesting; /* Track irq/process nesting level. */ 42 /* Process level is worth LLONG_MAX/2. */ 43 int dynticks_nmi_nesting; /* Track NMI nesting level. */ 44 atomic_t dynticks; /* Even value for idle, else odd. */ 45 bool rcu_need_heavy_qs; /* GP old, need heavy quiescent state. */ 46 unsigned long rcu_qs_ctr; /* Light universal quiescent state ctr. */ 47 bool rcu_urgent_qs; /* GP old need light quiescent state. */ 48 #ifdef CONFIG_RCU_FAST_NO_HZ 49 bool all_lazy; /* Are all CPU's CBs lazy? */ 50 unsigned long nonlazy_posted; 51 /* # times non-lazy CBs posted to CPU. */ 52 unsigned long nonlazy_posted_snap; 53 /* idle-period nonlazy_posted snapshot. */ 54 unsigned long last_accelerate; 55 /* Last jiffy CBs were accelerated. */ 56 unsigned long last_advance_all; 57 /* Last jiffy CBs were all advanced. */ 58 int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */ 59 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ 60 }; 61 62 /* RCU's kthread states for tracing. */ 63 #define RCU_KTHREAD_STOPPED 0 64 #define RCU_KTHREAD_RUNNING 1 65 #define RCU_KTHREAD_WAITING 2 66 #define RCU_KTHREAD_OFFCPU 3 67 #define RCU_KTHREAD_YIELDING 4 68 #define RCU_KTHREAD_MAX 4 69 70 /* 71 * Definition for node within the RCU grace-period-detection hierarchy. 72 */ 73 struct rcu_node { 74 raw_spinlock_t __private lock; /* Root rcu_node's lock protects */ 75 /* some rcu_state fields as well as */ 76 /* following. */ 77 unsigned long gpnum; /* Current grace period for this node. */ 78 /* This will either be equal to or one */ 79 /* behind the root rcu_node's gpnum. */ 80 unsigned long completed; /* Last GP completed for this node. */ 81 /* This will either be equal to or one */ 82 /* behind the root rcu_node's gpnum. */ 83 unsigned long qsmask; /* CPUs or groups that need to switch in */ 84 /* order for current grace period to proceed.*/ 85 /* In leaf rcu_node, each bit corresponds to */ 86 /* an rcu_data structure, otherwise, each */ 87 /* bit corresponds to a child rcu_node */ 88 /* structure. */ 89 unsigned long qsmaskinit; 90 /* Per-GP initial value for qsmask. */ 91 /* Initialized from ->qsmaskinitnext at the */ 92 /* beginning of each grace period. */ 93 unsigned long qsmaskinitnext; 94 /* Online CPUs for next grace period. */ 95 unsigned long expmask; /* CPUs or groups that need to check in */ 96 /* to allow the current expedited GP */ 97 /* to complete. */ 98 unsigned long expmaskinit; 99 /* Per-GP initial values for expmask. */ 100 /* Initialized from ->expmaskinitnext at the */ 101 /* beginning of each expedited GP. */ 102 unsigned long expmaskinitnext; 103 /* Online CPUs for next expedited GP. */ 104 /* Any CPU that has ever been online will */ 105 /* have its bit set. */ 106 unsigned long ffmask; /* Fully functional CPUs. */ 107 unsigned long grpmask; /* Mask to apply to parent qsmask. */ 108 /* Only one bit will be set in this mask. */ 109 int grplo; /* lowest-numbered CPU or group here. */ 110 int grphi; /* highest-numbered CPU or group here. */ 111 u8 grpnum; /* CPU/group number for next level up. */ 112 u8 level; /* root is at level 0. */ 113 bool wait_blkd_tasks;/* Necessary to wait for blocked tasks to */ 114 /* exit RCU read-side critical sections */ 115 /* before propagating offline up the */ 116 /* rcu_node tree? */ 117 struct rcu_node *parent; 118 struct list_head blkd_tasks; 119 /* Tasks blocked in RCU read-side critical */ 120 /* section. Tasks are placed at the head */ 121 /* of this list and age towards the tail. */ 122 struct list_head *gp_tasks; 123 /* Pointer to the first task blocking the */ 124 /* current grace period, or NULL if there */ 125 /* is no such task. */ 126 struct list_head *exp_tasks; 127 /* Pointer to the first task blocking the */ 128 /* current expedited grace period, or NULL */ 129 /* if there is no such task. If there */ 130 /* is no current expedited grace period, */ 131 /* then there can cannot be any such task. */ 132 struct list_head *boost_tasks; 133 /* Pointer to first task that needs to be */ 134 /* priority boosted, or NULL if no priority */ 135 /* boosting is needed for this rcu_node */ 136 /* structure. If there are no tasks */ 137 /* queued on this rcu_node structure that */ 138 /* are blocking the current grace period, */ 139 /* there can be no such task. */ 140 struct rt_mutex boost_mtx; 141 /* Used only for the priority-boosting */ 142 /* side effect, not as a lock. */ 143 unsigned long boost_time; 144 /* When to start boosting (jiffies). */ 145 struct task_struct *boost_kthread_task; 146 /* kthread that takes care of priority */ 147 /* boosting for this rcu_node structure. */ 148 unsigned int boost_kthread_status; 149 /* State of boost_kthread_task for tracing. */ 150 unsigned long n_tasks_boosted; 151 /* Total number of tasks boosted. */ 152 unsigned long n_exp_boosts; 153 /* Number of tasks boosted for expedited GP. */ 154 unsigned long n_normal_boosts; 155 /* Number of tasks boosted for normal GP. */ 156 #ifdef CONFIG_RCU_NOCB_CPU 157 struct swait_queue_head nocb_gp_wq[2]; 158 /* Place for rcu_nocb_kthread() to wait GP. */ 159 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 160 int need_future_gp[2]; 161 /* Counts of upcoming no-CB GP requests. */ 162 raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp; 163 164 spinlock_t exp_lock ____cacheline_internodealigned_in_smp; 165 unsigned long exp_seq_rq; 166 wait_queue_head_t exp_wq[4]; 167 } ____cacheline_internodealigned_in_smp; 168 169 /* 170 * Bitmasks in an rcu_node cover the interval [grplo, grphi] of CPU IDs, and 171 * are indexed relative to this interval rather than the global CPU ID space. 172 * This generates the bit for a CPU in node-local masks. 173 */ 174 #define leaf_node_cpu_bit(rnp, cpu) (1UL << ((cpu) - (rnp)->grplo)) 175 176 /* 177 * Union to allow "aggregate OR" operation on the need for a quiescent 178 * state by the normal and expedited grace periods. 179 */ 180 union rcu_noqs { 181 struct { 182 u8 norm; 183 u8 exp; 184 } b; /* Bits. */ 185 u16 s; /* Set of bits, aggregate OR here. */ 186 }; 187 188 /* Index values for nxttail array in struct rcu_data. */ 189 #define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */ 190 #define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */ 191 #define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */ 192 #define RCU_NEXT_TAIL 3 193 #define RCU_NEXT_SIZE 4 194 195 /* Per-CPU data for read-copy update. */ 196 struct rcu_data { 197 /* 1) quiescent-state and grace-period handling : */ 198 unsigned long completed; /* Track rsp->completed gp number */ 199 /* in order to detect GP end. */ 200 unsigned long gpnum; /* Highest gp number that this CPU */ 201 /* is aware of having started. */ 202 unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */ 203 /* for rcu_all_qs() invocations. */ 204 union rcu_noqs cpu_no_qs; /* No QSes yet for this CPU. */ 205 bool core_needs_qs; /* Core waits for quiesc state. */ 206 bool beenonline; /* CPU online at least once. */ 207 bool gpwrap; /* Possible gpnum/completed wrap. */ 208 struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ 209 unsigned long grpmask; /* Mask to apply to leaf qsmask. */ 210 unsigned long ticks_this_gp; /* The number of scheduling-clock */ 211 /* ticks this CPU has handled */ 212 /* during and after the last grace */ 213 /* period it is aware of. */ 214 215 /* 2) batch handling */ 216 struct rcu_segcblist cblist; /* Segmented callback list, with */ 217 /* different callbacks waiting for */ 218 /* different grace periods. */ 219 long qlen_last_fqs_check; 220 /* qlen at last check for QS forcing */ 221 unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ 222 unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */ 223 unsigned long n_force_qs_snap; 224 /* did other CPU force QS recently? */ 225 long blimit; /* Upper limit on a processed batch */ 226 227 /* 3) dynticks interface. */ 228 struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ 229 int dynticks_snap; /* Per-GP tracking for dynticks. */ 230 231 /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ 232 unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */ 233 unsigned long offline_fqs; /* Kicked due to being offline. */ 234 unsigned long cond_resched_completed; 235 /* Grace period that needs help */ 236 /* from cond_resched(). */ 237 238 /* 5) __rcu_pending() statistics. */ 239 unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ 240 unsigned long n_rp_core_needs_qs; 241 unsigned long n_rp_report_qs; 242 unsigned long n_rp_cb_ready; 243 unsigned long n_rp_cpu_needs_gp; 244 unsigned long n_rp_gp_completed; 245 unsigned long n_rp_gp_started; 246 unsigned long n_rp_nocb_defer_wakeup; 247 unsigned long n_rp_need_nothing; 248 249 /* 6) _rcu_barrier(), OOM callbacks, and expediting. */ 250 struct rcu_head barrier_head; 251 #ifdef CONFIG_RCU_FAST_NO_HZ 252 struct rcu_head oom_head; 253 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ 254 atomic_long_t exp_workdone0; /* # done by workqueue. */ 255 atomic_long_t exp_workdone1; /* # done by others #1. */ 256 atomic_long_t exp_workdone2; /* # done by others #2. */ 257 atomic_long_t exp_workdone3; /* # done by others #3. */ 258 int exp_dynticks_snap; /* Double-check need for IPI. */ 259 260 /* 7) Callback offloading. */ 261 #ifdef CONFIG_RCU_NOCB_CPU 262 struct rcu_head *nocb_head; /* CBs waiting for kthread. */ 263 struct rcu_head **nocb_tail; 264 atomic_long_t nocb_q_count; /* # CBs waiting for nocb */ 265 atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */ 266 struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */ 267 struct rcu_head **nocb_follower_tail; 268 struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */ 269 struct task_struct *nocb_kthread; 270 raw_spinlock_t nocb_lock; /* Guard following pair of fields. */ 271 int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ 272 struct timer_list nocb_timer; /* Enforce finite deferral. */ 273 274 /* The following fields are used by the leader, hence own cacheline. */ 275 struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; 276 /* CBs waiting for GP. */ 277 struct rcu_head **nocb_gp_tail; 278 bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */ 279 struct rcu_data *nocb_next_follower; 280 /* Next follower in wakeup chain. */ 281 282 /* The following fields are used by the follower, hence new cachline. */ 283 struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp; 284 /* Leader CPU takes GP-end wakeups. */ 285 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 286 287 /* 8) RCU CPU stall data. */ 288 unsigned int softirq_snap; /* Snapshot of softirq activity. */ 289 /* ->rcu_iw* fields protected by leaf rcu_node ->lock. */ 290 struct irq_work rcu_iw; /* Check for non-irq activity. */ 291 bool rcu_iw_pending; /* Is ->rcu_iw pending? */ 292 unsigned long rcu_iw_gpnum; /* ->gpnum associated with ->rcu_iw. */ 293 294 int cpu; 295 struct rcu_state *rsp; 296 }; 297 298 /* Values for nocb_defer_wakeup field in struct rcu_data. */ 299 #define RCU_NOCB_WAKE_NOT 0 300 #define RCU_NOCB_WAKE 1 301 #define RCU_NOCB_WAKE_FORCE 2 302 303 #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500)) 304 /* For jiffies_till_first_fqs and */ 305 /* and jiffies_till_next_fqs. */ 306 307 #define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */ 308 /* delay between bouts of */ 309 /* quiescent-state forcing. */ 310 311 #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */ 312 /* at least one scheduling clock */ 313 /* irq before ratting on them. */ 314 315 #define rcu_wait(cond) \ 316 do { \ 317 for (;;) { \ 318 set_current_state(TASK_INTERRUPTIBLE); \ 319 if (cond) \ 320 break; \ 321 schedule(); \ 322 } \ 323 __set_current_state(TASK_RUNNING); \ 324 } while (0) 325 326 /* 327 * RCU global state, including node hierarchy. This hierarchy is 328 * represented in "heap" form in a dense array. The root (first level) 329 * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second 330 * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), 331 * and the third level in ->node[m+1] and following (->node[m+1] referenced 332 * by ->level[2]). The number of levels is determined by the number of 333 * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" 334 * consisting of a single rcu_node. 335 */ 336 struct rcu_state { 337 struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ 338 struct rcu_node *level[RCU_NUM_LVLS + 1]; 339 /* Hierarchy levels (+1 to */ 340 /* shut bogus gcc warning) */ 341 struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ 342 call_rcu_func_t call; /* call_rcu() flavor. */ 343 int ncpus; /* # CPUs seen so far. */ 344 345 /* The following fields are guarded by the root rcu_node's lock. */ 346 347 u8 boost ____cacheline_internodealigned_in_smp; 348 /* Subject to priority boost. */ 349 unsigned long gpnum; /* Current gp number. */ 350 unsigned long completed; /* # of last completed gp. */ 351 struct task_struct *gp_kthread; /* Task for grace periods. */ 352 struct swait_queue_head gp_wq; /* Where GP task waits. */ 353 short gp_flags; /* Commands for GP task. */ 354 short gp_state; /* GP kthread sleep state. */ 355 356 /* End of fields guarded by root rcu_node's lock. */ 357 358 struct mutex barrier_mutex; /* Guards barrier fields. */ 359 atomic_t barrier_cpu_count; /* # CPUs waiting on. */ 360 struct completion barrier_completion; /* Wake at barrier end. */ 361 unsigned long barrier_sequence; /* ++ at start and end of */ 362 /* _rcu_barrier(). */ 363 /* End of fields guarded by barrier_mutex. */ 364 365 struct mutex exp_mutex; /* Serialize expedited GP. */ 366 struct mutex exp_wake_mutex; /* Serialize wakeup. */ 367 unsigned long expedited_sequence; /* Take a ticket. */ 368 atomic_t expedited_need_qs; /* # CPUs left to check in. */ 369 struct swait_queue_head expedited_wq; /* Wait for check-ins. */ 370 int ncpus_snap; /* # CPUs seen last time. */ 371 372 unsigned long jiffies_force_qs; /* Time at which to invoke */ 373 /* force_quiescent_state(). */ 374 unsigned long jiffies_kick_kthreads; /* Time at which to kick */ 375 /* kthreads, if configured. */ 376 unsigned long n_force_qs; /* Number of calls to */ 377 /* force_quiescent_state(). */ 378 unsigned long n_force_qs_lh; /* ~Number of calls leaving */ 379 /* due to lock unavailable. */ 380 unsigned long n_force_qs_ngp; /* Number of calls leaving */ 381 /* due to no GP active. */ 382 unsigned long gp_start; /* Time at which GP started, */ 383 /* but in jiffies. */ 384 unsigned long gp_activity; /* Time of last GP kthread */ 385 /* activity in jiffies. */ 386 unsigned long jiffies_stall; /* Time at which to check */ 387 /* for CPU stalls. */ 388 unsigned long jiffies_resched; /* Time at which to resched */ 389 /* a reluctant CPU. */ 390 unsigned long n_force_qs_gpstart; /* Snapshot of n_force_qs at */ 391 /* GP start. */ 392 unsigned long gp_max; /* Maximum GP duration in */ 393 /* jiffies. */ 394 const char *name; /* Name of structure. */ 395 char abbr; /* Abbreviated name. */ 396 struct list_head flavors; /* List of RCU flavors. */ 397 }; 398 399 /* Values for rcu_state structure's gp_flags field. */ 400 #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ 401 #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ 402 403 /* Values for rcu_state structure's gp_state field. */ 404 #define RCU_GP_IDLE 0 /* Initial state and no GP in progress. */ 405 #define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */ 406 #define RCU_GP_DONE_GPS 2 /* Wait done for grace-period start. */ 407 #define RCU_GP_WAIT_FQS 3 /* Wait for force-quiescent-state time. */ 408 #define RCU_GP_DOING_FQS 4 /* Wait done for force-quiescent-state time. */ 409 #define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */ 410 #define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */ 411 412 #ifndef RCU_TREE_NONCORE 413 static const char * const gp_state_names[] = { 414 "RCU_GP_IDLE", 415 "RCU_GP_WAIT_GPS", 416 "RCU_GP_DONE_GPS", 417 "RCU_GP_WAIT_FQS", 418 "RCU_GP_DOING_FQS", 419 "RCU_GP_CLEANUP", 420 "RCU_GP_CLEANED", 421 }; 422 #endif /* #ifndef RCU_TREE_NONCORE */ 423 424 extern struct list_head rcu_struct_flavors; 425 426 /* Sequence through rcu_state structures for each RCU flavor. */ 427 #define for_each_rcu_flavor(rsp) \ 428 list_for_each_entry((rsp), &rcu_struct_flavors, flavors) 429 430 /* 431 * RCU implementation internal declarations: 432 */ 433 extern struct rcu_state rcu_sched_state; 434 435 extern struct rcu_state rcu_bh_state; 436 437 #ifdef CONFIG_PREEMPT_RCU 438 extern struct rcu_state rcu_preempt_state; 439 #endif /* #ifdef CONFIG_PREEMPT_RCU */ 440 441 int rcu_dynticks_snap(struct rcu_dynticks *rdtp); 442 bool rcu_eqs_special_set(int cpu); 443 444 #ifdef CONFIG_RCU_BOOST 445 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); 446 DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); 447 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); 448 DECLARE_PER_CPU(char, rcu_cpu_has_work); 449 #endif /* #ifdef CONFIG_RCU_BOOST */ 450 451 #ifndef RCU_TREE_NONCORE 452 453 /* Forward declarations for rcutree_plugin.h */ 454 static void rcu_bootup_announce(void); 455 static void rcu_preempt_note_context_switch(bool preempt); 456 static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); 457 #ifdef CONFIG_HOTPLUG_CPU 458 static bool rcu_preempt_has_tasks(struct rcu_node *rnp); 459 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 460 static void rcu_print_detail_task_stall(struct rcu_state *rsp); 461 static int rcu_print_task_stall(struct rcu_node *rnp); 462 static int rcu_print_task_exp_stall(struct rcu_node *rnp); 463 static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); 464 static void rcu_preempt_check_callbacks(void); 465 void call_rcu(struct rcu_head *head, rcu_callback_t func); 466 static void __init __rcu_init_preempt(void); 467 static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); 468 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); 469 static void invoke_rcu_callbacks_kthread(void); 470 static bool rcu_is_callbacks_kthread(void); 471 #ifdef CONFIG_RCU_BOOST 472 static void rcu_preempt_do_callbacks(void); 473 static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, 474 struct rcu_node *rnp); 475 #endif /* #ifdef CONFIG_RCU_BOOST */ 476 static void __init rcu_spawn_boost_kthreads(void); 477 static void rcu_prepare_kthreads(int cpu); 478 static void rcu_cleanup_after_idle(void); 479 static void rcu_prepare_for_idle(void); 480 static void rcu_idle_count_callbacks_posted(void); 481 static bool rcu_preempt_has_tasks(struct rcu_node *rnp); 482 static void print_cpu_stall_info_begin(void); 483 static void print_cpu_stall_info(struct rcu_state *rsp, int cpu); 484 static void print_cpu_stall_info_end(void); 485 static void zero_cpu_stall_ticks(struct rcu_data *rdp); 486 static void increment_cpu_stall_ticks(void); 487 static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu); 488 static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq); 489 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp); 490 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq); 491 static void rcu_init_one_nocb(struct rcu_node *rnp); 492 static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, 493 bool lazy, unsigned long flags); 494 static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp, 495 struct rcu_data *rdp, 496 unsigned long flags); 497 static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); 498 static void do_nocb_deferred_wakeup(struct rcu_data *rdp); 499 static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); 500 static void rcu_spawn_all_nocb_kthreads(int cpu); 501 static void __init rcu_spawn_nocb_kthreads(void); 502 #ifdef CONFIG_RCU_NOCB_CPU 503 static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp); 504 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 505 static void __maybe_unused rcu_kick_nohz_cpu(int cpu); 506 static bool init_nocb_callback_list(struct rcu_data *rdp); 507 static void rcu_bind_gp_kthread(void); 508 static bool rcu_nohz_full_cpu(struct rcu_state *rsp); 509 static void rcu_dynticks_task_enter(void); 510 static void rcu_dynticks_task_exit(void); 511 512 #ifdef CONFIG_SRCU 513 void srcu_online_cpu(unsigned int cpu); 514 void srcu_offline_cpu(unsigned int cpu); 515 #else /* #ifdef CONFIG_SRCU */ 516 void srcu_online_cpu(unsigned int cpu) { } 517 void srcu_offline_cpu(unsigned int cpu) { } 518 #endif /* #else #ifdef CONFIG_SRCU */ 519 520 #endif /* #ifndef RCU_TREE_NONCORE */ 521