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 #ifdef CONFIG_RCU_NOCB_CPU 150 struct swait_queue_head nocb_gp_wq[2]; 151 /* Place for rcu_nocb_kthread() to wait GP. */ 152 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 153 int need_future_gp[2]; 154 /* Counts of upcoming no-CB GP requests. */ 155 raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp; 156 157 spinlock_t exp_lock ____cacheline_internodealigned_in_smp; 158 unsigned long exp_seq_rq; 159 wait_queue_head_t exp_wq[4]; 160 } ____cacheline_internodealigned_in_smp; 161 162 /* 163 * Bitmasks in an rcu_node cover the interval [grplo, grphi] of CPU IDs, and 164 * are indexed relative to this interval rather than the global CPU ID space. 165 * This generates the bit for a CPU in node-local masks. 166 */ 167 #define leaf_node_cpu_bit(rnp, cpu) (1UL << ((cpu) - (rnp)->grplo)) 168 169 /* 170 * Union to allow "aggregate OR" operation on the need for a quiescent 171 * state by the normal and expedited grace periods. 172 */ 173 union rcu_noqs { 174 struct { 175 u8 norm; 176 u8 exp; 177 } b; /* Bits. */ 178 u16 s; /* Set of bits, aggregate OR here. */ 179 }; 180 181 /* Per-CPU data for read-copy update. */ 182 struct rcu_data { 183 /* 1) quiescent-state and grace-period handling : */ 184 unsigned long completed; /* Track rsp->completed gp number */ 185 /* in order to detect GP end. */ 186 unsigned long gpnum; /* Highest gp number that this CPU */ 187 /* is aware of having started. */ 188 unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */ 189 /* for rcu_all_qs() invocations. */ 190 union rcu_noqs cpu_no_qs; /* No QSes yet for this CPU. */ 191 bool core_needs_qs; /* Core waits for quiesc state. */ 192 bool beenonline; /* CPU online at least once. */ 193 bool gpwrap; /* Possible gpnum/completed wrap. */ 194 struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ 195 unsigned long grpmask; /* Mask to apply to leaf qsmask. */ 196 unsigned long ticks_this_gp; /* The number of scheduling-clock */ 197 /* ticks this CPU has handled */ 198 /* during and after the last grace */ 199 /* period it is aware of. */ 200 201 /* 2) batch handling */ 202 struct rcu_segcblist cblist; /* Segmented callback list, with */ 203 /* different callbacks waiting for */ 204 /* different grace periods. */ 205 long qlen_last_fqs_check; 206 /* qlen at last check for QS forcing */ 207 unsigned long n_force_qs_snap; 208 /* did other CPU force QS recently? */ 209 long blimit; /* Upper limit on a processed batch */ 210 211 /* 3) dynticks interface. */ 212 struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ 213 int dynticks_snap; /* Per-GP tracking for dynticks. */ 214 215 /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ 216 unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */ 217 unsigned long offline_fqs; /* Kicked due to being offline. */ 218 unsigned long cond_resched_completed; 219 /* Grace period that needs help */ 220 /* from cond_resched(). */ 221 222 /* 5) _rcu_barrier(), OOM callbacks, and expediting. */ 223 struct rcu_head barrier_head; 224 #ifdef CONFIG_RCU_FAST_NO_HZ 225 struct rcu_head oom_head; 226 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ 227 atomic_long_t exp_workdone0; /* # done by workqueue. */ 228 atomic_long_t exp_workdone1; /* # done by others #1. */ 229 atomic_long_t exp_workdone2; /* # done by others #2. */ 230 atomic_long_t exp_workdone3; /* # done by others #3. */ 231 int exp_dynticks_snap; /* Double-check need for IPI. */ 232 233 /* 6) Callback offloading. */ 234 #ifdef CONFIG_RCU_NOCB_CPU 235 struct rcu_head *nocb_head; /* CBs waiting for kthread. */ 236 struct rcu_head **nocb_tail; 237 atomic_long_t nocb_q_count; /* # CBs waiting for nocb */ 238 atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */ 239 struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */ 240 struct rcu_head **nocb_follower_tail; 241 struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */ 242 struct task_struct *nocb_kthread; 243 raw_spinlock_t nocb_lock; /* Guard following pair of fields. */ 244 int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ 245 struct timer_list nocb_timer; /* Enforce finite deferral. */ 246 247 /* The following fields are used by the leader, hence own cacheline. */ 248 struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; 249 /* CBs waiting for GP. */ 250 struct rcu_head **nocb_gp_tail; 251 bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */ 252 struct rcu_data *nocb_next_follower; 253 /* Next follower in wakeup chain. */ 254 255 /* The following fields are used by the follower, hence new cachline. */ 256 struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp; 257 /* Leader CPU takes GP-end wakeups. */ 258 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 259 260 /* 7) RCU CPU stall data. */ 261 unsigned int softirq_snap; /* Snapshot of softirq activity. */ 262 /* ->rcu_iw* fields protected by leaf rcu_node ->lock. */ 263 struct irq_work rcu_iw; /* Check for non-irq activity. */ 264 bool rcu_iw_pending; /* Is ->rcu_iw pending? */ 265 unsigned long rcu_iw_gpnum; /* ->gpnum associated with ->rcu_iw. */ 266 267 int cpu; 268 struct rcu_state *rsp; 269 }; 270 271 /* Values for nocb_defer_wakeup field in struct rcu_data. */ 272 #define RCU_NOCB_WAKE_NOT 0 273 #define RCU_NOCB_WAKE 1 274 #define RCU_NOCB_WAKE_FORCE 2 275 276 #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500)) 277 /* For jiffies_till_first_fqs and */ 278 /* and jiffies_till_next_fqs. */ 279 280 #define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */ 281 /* delay between bouts of */ 282 /* quiescent-state forcing. */ 283 284 #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */ 285 /* at least one scheduling clock */ 286 /* irq before ratting on them. */ 287 288 #define rcu_wait(cond) \ 289 do { \ 290 for (;;) { \ 291 set_current_state(TASK_INTERRUPTIBLE); \ 292 if (cond) \ 293 break; \ 294 schedule(); \ 295 } \ 296 __set_current_state(TASK_RUNNING); \ 297 } while (0) 298 299 /* 300 * RCU global state, including node hierarchy. This hierarchy is 301 * represented in "heap" form in a dense array. The root (first level) 302 * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second 303 * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), 304 * and the third level in ->node[m+1] and following (->node[m+1] referenced 305 * by ->level[2]). The number of levels is determined by the number of 306 * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" 307 * consisting of a single rcu_node. 308 */ 309 struct rcu_state { 310 struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ 311 struct rcu_node *level[RCU_NUM_LVLS + 1]; 312 /* Hierarchy levels (+1 to */ 313 /* shut bogus gcc warning) */ 314 struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ 315 call_rcu_func_t call; /* call_rcu() flavor. */ 316 int ncpus; /* # CPUs seen so far. */ 317 318 /* The following fields are guarded by the root rcu_node's lock. */ 319 320 u8 boost ____cacheline_internodealigned_in_smp; 321 /* Subject to priority boost. */ 322 unsigned long gpnum; /* Current gp number. */ 323 unsigned long completed; /* # of last completed gp. */ 324 struct task_struct *gp_kthread; /* Task for grace periods. */ 325 struct swait_queue_head gp_wq; /* Where GP task waits. */ 326 short gp_flags; /* Commands for GP task. */ 327 short gp_state; /* GP kthread sleep state. */ 328 329 /* End of fields guarded by root rcu_node's lock. */ 330 331 struct mutex barrier_mutex; /* Guards barrier fields. */ 332 atomic_t barrier_cpu_count; /* # CPUs waiting on. */ 333 struct completion barrier_completion; /* Wake at barrier end. */ 334 unsigned long barrier_sequence; /* ++ at start and end of */ 335 /* _rcu_barrier(). */ 336 /* End of fields guarded by barrier_mutex. */ 337 338 struct mutex exp_mutex; /* Serialize expedited GP. */ 339 struct mutex exp_wake_mutex; /* Serialize wakeup. */ 340 unsigned long expedited_sequence; /* Take a ticket. */ 341 atomic_t expedited_need_qs; /* # CPUs left to check in. */ 342 struct swait_queue_head expedited_wq; /* Wait for check-ins. */ 343 int ncpus_snap; /* # CPUs seen last time. */ 344 345 unsigned long jiffies_force_qs; /* Time at which to invoke */ 346 /* force_quiescent_state(). */ 347 unsigned long jiffies_kick_kthreads; /* Time at which to kick */ 348 /* kthreads, if configured. */ 349 unsigned long n_force_qs; /* Number of calls to */ 350 /* force_quiescent_state(). */ 351 unsigned long gp_start; /* Time at which GP started, */ 352 /* but in jiffies. */ 353 unsigned long gp_activity; /* Time of last GP kthread */ 354 /* activity in jiffies. */ 355 unsigned long jiffies_stall; /* Time at which to check */ 356 /* for CPU stalls. */ 357 unsigned long jiffies_resched; /* Time at which to resched */ 358 /* a reluctant CPU. */ 359 unsigned long n_force_qs_gpstart; /* Snapshot of n_force_qs at */ 360 /* GP start. */ 361 unsigned long gp_max; /* Maximum GP duration in */ 362 /* jiffies. */ 363 const char *name; /* Name of structure. */ 364 char abbr; /* Abbreviated name. */ 365 struct list_head flavors; /* List of RCU flavors. */ 366 }; 367 368 /* Values for rcu_state structure's gp_flags field. */ 369 #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ 370 #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ 371 372 /* Values for rcu_state structure's gp_state field. */ 373 #define RCU_GP_IDLE 0 /* Initial state and no GP in progress. */ 374 #define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */ 375 #define RCU_GP_DONE_GPS 2 /* Wait done for grace-period start. */ 376 #define RCU_GP_WAIT_FQS 3 /* Wait for force-quiescent-state time. */ 377 #define RCU_GP_DOING_FQS 4 /* Wait done for force-quiescent-state time. */ 378 #define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */ 379 #define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */ 380 381 #ifndef RCU_TREE_NONCORE 382 static const char * const gp_state_names[] = { 383 "RCU_GP_IDLE", 384 "RCU_GP_WAIT_GPS", 385 "RCU_GP_DONE_GPS", 386 "RCU_GP_WAIT_FQS", 387 "RCU_GP_DOING_FQS", 388 "RCU_GP_CLEANUP", 389 "RCU_GP_CLEANED", 390 }; 391 #endif /* #ifndef RCU_TREE_NONCORE */ 392 393 extern struct list_head rcu_struct_flavors; 394 395 /* Sequence through rcu_state structures for each RCU flavor. */ 396 #define for_each_rcu_flavor(rsp) \ 397 list_for_each_entry((rsp), &rcu_struct_flavors, flavors) 398 399 /* 400 * RCU implementation internal declarations: 401 */ 402 extern struct rcu_state rcu_sched_state; 403 404 extern struct rcu_state rcu_bh_state; 405 406 #ifdef CONFIG_PREEMPT_RCU 407 extern struct rcu_state rcu_preempt_state; 408 #endif /* #ifdef CONFIG_PREEMPT_RCU */ 409 410 int rcu_dynticks_snap(struct rcu_dynticks *rdtp); 411 bool rcu_eqs_special_set(int cpu); 412 413 #ifdef CONFIG_RCU_BOOST 414 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); 415 DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); 416 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); 417 DECLARE_PER_CPU(char, rcu_cpu_has_work); 418 #endif /* #ifdef CONFIG_RCU_BOOST */ 419 420 #ifndef RCU_TREE_NONCORE 421 422 /* Forward declarations for rcutree_plugin.h */ 423 static void rcu_bootup_announce(void); 424 static void rcu_preempt_note_context_switch(bool preempt); 425 static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); 426 #ifdef CONFIG_HOTPLUG_CPU 427 static bool rcu_preempt_has_tasks(struct rcu_node *rnp); 428 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 429 static void rcu_print_detail_task_stall(struct rcu_state *rsp); 430 static int rcu_print_task_stall(struct rcu_node *rnp); 431 static int rcu_print_task_exp_stall(struct rcu_node *rnp); 432 static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); 433 static void rcu_preempt_check_callbacks(void); 434 void call_rcu(struct rcu_head *head, rcu_callback_t func); 435 static void __init __rcu_init_preempt(void); 436 static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); 437 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); 438 static void invoke_rcu_callbacks_kthread(void); 439 static bool rcu_is_callbacks_kthread(void); 440 #ifdef CONFIG_RCU_BOOST 441 static void rcu_preempt_do_callbacks(void); 442 static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, 443 struct rcu_node *rnp); 444 #endif /* #ifdef CONFIG_RCU_BOOST */ 445 static void __init rcu_spawn_boost_kthreads(void); 446 static void rcu_prepare_kthreads(int cpu); 447 static void rcu_cleanup_after_idle(void); 448 static void rcu_prepare_for_idle(void); 449 static void rcu_idle_count_callbacks_posted(void); 450 static bool rcu_preempt_has_tasks(struct rcu_node *rnp); 451 static void print_cpu_stall_info_begin(void); 452 static void print_cpu_stall_info(struct rcu_state *rsp, int cpu); 453 static void print_cpu_stall_info_end(void); 454 static void zero_cpu_stall_ticks(struct rcu_data *rdp); 455 static void increment_cpu_stall_ticks(void); 456 static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu); 457 static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq); 458 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp); 459 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq); 460 static void rcu_init_one_nocb(struct rcu_node *rnp); 461 static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, 462 bool lazy, unsigned long flags); 463 static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp, 464 struct rcu_data *rdp, 465 unsigned long flags); 466 static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); 467 static void do_nocb_deferred_wakeup(struct rcu_data *rdp); 468 static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); 469 static void rcu_spawn_all_nocb_kthreads(int cpu); 470 static void __init rcu_spawn_nocb_kthreads(void); 471 #ifdef CONFIG_RCU_NOCB_CPU 472 static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp); 473 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ 474 static void __maybe_unused rcu_kick_nohz_cpu(int cpu); 475 static bool init_nocb_callback_list(struct rcu_data *rdp); 476 static void rcu_bind_gp_kthread(void); 477 static bool rcu_nohz_full_cpu(struct rcu_state *rsp); 478 static void rcu_dynticks_task_enter(void); 479 static void rcu_dynticks_task_exit(void); 480 481 #ifdef CONFIG_SRCU 482 void srcu_online_cpu(unsigned int cpu); 483 void srcu_offline_cpu(unsigned int cpu); 484 #else /* #ifdef CONFIG_SRCU */ 485 void srcu_online_cpu(unsigned int cpu) { } 486 void srcu_offline_cpu(unsigned int cpu) { } 487 #endif /* #else #ifdef CONFIG_SRCU */ 488 489 #endif /* #ifndef RCU_TREE_NONCORE */ 490