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, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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/threads.h>
28 #include <linux/cpumask.h>
29 #include <linux/seqlock.h>
30 #include <linux/irq_work.h>
31
32 /*
33 * Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and
34 * CONFIG_RCU_FANOUT_LEAF.
35 * In theory, it should be possible to add more levels straightforwardly.
36 * In practice, this did work well going from three levels to four.
37 * Of course, your mileage may vary.
38 */
39 #define MAX_RCU_LVLS 4
40 #define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF)
41 #define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT)
42 #define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT)
43 #define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT)
44
45 #if NR_CPUS <= RCU_FANOUT_1
46 # define RCU_NUM_LVLS 1
47 # define NUM_RCU_LVL_0 1
48 # define NUM_RCU_LVL_1 (NR_CPUS)
49 # define NUM_RCU_LVL_2 0
50 # define NUM_RCU_LVL_3 0
51 # define NUM_RCU_LVL_4 0
52 #elif NR_CPUS <= RCU_FANOUT_2
53 # define RCU_NUM_LVLS 2
54 # define NUM_RCU_LVL_0 1
55 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
56 # define NUM_RCU_LVL_2 (NR_CPUS)
57 # define NUM_RCU_LVL_3 0
58 # define NUM_RCU_LVL_4 0
59 #elif NR_CPUS <= RCU_FANOUT_3
60 # define RCU_NUM_LVLS 3
61 # define NUM_RCU_LVL_0 1
62 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
63 # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
64 # define NUM_RCU_LVL_3 (NR_CPUS)
65 # define NUM_RCU_LVL_4 0
66 #elif NR_CPUS <= RCU_FANOUT_4
67 # define RCU_NUM_LVLS 4
68 # define NUM_RCU_LVL_0 1
69 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
70 # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
71 # define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
72 # define NUM_RCU_LVL_4 (NR_CPUS)
73 #else
74 # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
75 #endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */
76
77 #define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4)
78 #define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
79
80 extern int rcu_num_lvls;
81 extern int rcu_num_nodes;
82
83 /*
84 * Dynticks per-CPU state.
85 */
86 struct rcu_dynticks {
87 long long dynticks_nesting; /* Track irq/process nesting level. */
88 /* Process level is worth LLONG_MAX/2. */
89 int dynticks_nmi_nesting; /* Track NMI nesting level. */
90 atomic_t dynticks; /* Even value for idle, else odd. */
91 #ifdef CONFIG_RCU_FAST_NO_HZ
92 bool all_lazy; /* Are all CPU's CBs lazy? */
93 unsigned long nonlazy_posted;
94 /* # times non-lazy CBs posted to CPU. */
95 unsigned long nonlazy_posted_snap;
96 /* idle-period nonlazy_posted snapshot. */
97 unsigned long last_accelerate;
98 /* Last jiffy CBs were accelerated. */
99 int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
100 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
101 };
102
103 /* RCU's kthread states for tracing. */
104 #define RCU_KTHREAD_STOPPED 0
105 #define RCU_KTHREAD_RUNNING 1
106 #define RCU_KTHREAD_WAITING 2
107 #define RCU_KTHREAD_OFFCPU 3
108 #define RCU_KTHREAD_YIELDING 4
109 #define RCU_KTHREAD_MAX 4
110
111 /*
112 * Definition for node within the RCU grace-period-detection hierarchy.
113 */
114 struct rcu_node {
115 raw_spinlock_t lock; /* Root rcu_node's lock protects some */
116 /* rcu_state fields as well as following. */
117 unsigned long gpnum; /* Current grace period for this node. */
118 /* This will either be equal to or one */
119 /* behind the root rcu_node's gpnum. */
120 unsigned long completed; /* Last GP completed for this node. */
121 /* This will either be equal to or one */
122 /* behind the root rcu_node's gpnum. */
123 unsigned long qsmask; /* CPUs or groups that need to switch in */
124 /* order for current grace period to proceed.*/
125 /* In leaf rcu_node, each bit corresponds to */
126 /* an rcu_data structure, otherwise, each */
127 /* bit corresponds to a child rcu_node */
128 /* structure. */
129 unsigned long expmask; /* Groups that have ->blkd_tasks */
130 /* elements that need to drain to allow the */
131 /* current expedited grace period to */
132 /* complete (only for TREE_PREEMPT_RCU). */
133 unsigned long qsmaskinit;
134 /* Per-GP initial value for qsmask & expmask. */
135 unsigned long grpmask; /* Mask to apply to parent qsmask. */
136 /* Only one bit will be set in this mask. */
137 int grplo; /* lowest-numbered CPU or group here. */
138 int grphi; /* highest-numbered CPU or group here. */
139 u8 grpnum; /* CPU/group number for next level up. */
140 u8 level; /* root is at level 0. */
141 struct rcu_node *parent;
142 struct list_head blkd_tasks;
143 /* Tasks blocked in RCU read-side critical */
144 /* section. Tasks are placed at the head */
145 /* of this list and age towards the tail. */
146 struct list_head *gp_tasks;
147 /* Pointer to the first task blocking the */
148 /* current grace period, or NULL if there */
149 /* is no such task. */
150 struct list_head *exp_tasks;
151 /* Pointer to the first task blocking the */
152 /* current expedited grace period, or NULL */
153 /* if there is no such task. If there */
154 /* is no current expedited grace period, */
155 /* then there can cannot be any such task. */
156 #ifdef CONFIG_RCU_BOOST
157 struct list_head *boost_tasks;
158 /* Pointer to first task that needs to be */
159 /* priority boosted, or NULL if no priority */
160 /* boosting is needed for this rcu_node */
161 /* structure. If there are no tasks */
162 /* queued on this rcu_node structure that */
163 /* are blocking the current grace period, */
164 /* there can be no such task. */
165 unsigned long boost_time;
166 /* When to start boosting (jiffies). */
167 struct task_struct *boost_kthread_task;
168 /* kthread that takes care of priority */
169 /* boosting for this rcu_node structure. */
170 unsigned int boost_kthread_status;
171 /* State of boost_kthread_task for tracing. */
172 unsigned long n_tasks_boosted;
173 /* Total number of tasks boosted. */
174 unsigned long n_exp_boosts;
175 /* Number of tasks boosted for expedited GP. */
176 unsigned long n_normal_boosts;
177 /* Number of tasks boosted for normal GP. */
178 unsigned long n_balk_blkd_tasks;
179 /* Refused to boost: no blocked tasks. */
180 unsigned long n_balk_exp_gp_tasks;
181 /* Refused to boost: nothing blocking GP. */
182 unsigned long n_balk_boost_tasks;
183 /* Refused to boost: already boosting. */
184 unsigned long n_balk_notblocked;
185 /* Refused to boost: RCU RS CS still running. */
186 unsigned long n_balk_notyet;
187 /* Refused to boost: not yet time. */
188 unsigned long n_balk_nos;
189 /* Refused to boost: not sure why, though. */
190 /* This can happen due to race conditions. */
191 #endif /* #ifdef CONFIG_RCU_BOOST */
192 #ifdef CONFIG_RCU_NOCB_CPU
193 wait_queue_head_t nocb_gp_wq[2];
194 /* Place for rcu_nocb_kthread() to wait GP. */
195 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */
196 int need_future_gp[2];
197 /* Counts of upcoming no-CB GP requests. */
198 raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp;
199 } ____cacheline_internodealigned_in_smp;
200
201 /*
202 * Do a full breadth-first scan of the rcu_node structures for the
203 * specified rcu_state structure.
204 */
205 #define rcu_for_each_node_breadth_first(rsp, rnp) \
206 for ((rnp) = &(rsp)->node[0]; \
207 (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)
208
209 /*
210 * Do a breadth-first scan of the non-leaf rcu_node structures for the
211 * specified rcu_state structure. Note that if there is a singleton
212 * rcu_node tree with but one rcu_node structure, this loop is a no-op.
213 */
214 #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
215 for ((rnp) = &(rsp)->node[0]; \
216 (rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++)
217
218 /*
219 * Scan the leaves of the rcu_node hierarchy for the specified rcu_state
220 * structure. Note that if there is a singleton rcu_node tree with but
221 * one rcu_node structure, this loop -will- visit the rcu_node structure.
222 * It is still a leaf node, even if it is also the root node.
223 */
224 #define rcu_for_each_leaf_node(rsp, rnp) \
225 for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \
226 (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)
227
228 /* Index values for nxttail array in struct rcu_data. */
229 #define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */
230 #define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */
231 #define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */
232 #define RCU_NEXT_TAIL 3
233 #define RCU_NEXT_SIZE 4
234
235 /* Per-CPU data for read-copy update. */
236 struct rcu_data {
237 /* 1) quiescent-state and grace-period handling : */
238 unsigned long completed; /* Track rsp->completed gp number */
239 /* in order to detect GP end. */
240 unsigned long gpnum; /* Highest gp number that this CPU */
241 /* is aware of having started. */
242 bool passed_quiesce; /* User-mode/idle loop etc. */
243 bool qs_pending; /* Core waits for quiesc state. */
244 bool beenonline; /* CPU online at least once. */
245 bool preemptible; /* Preemptible RCU? */
246 struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
247 unsigned long grpmask; /* Mask to apply to leaf qsmask. */
248 #ifdef CONFIG_RCU_CPU_STALL_INFO
249 unsigned long ticks_this_gp; /* The number of scheduling-clock */
250 /* ticks this CPU has handled */
251 /* during and after the last grace */
252 /* period it is aware of. */
253 #endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
254
255 /* 2) batch handling */
256 /*
257 * If nxtlist is not NULL, it is partitioned as follows.
258 * Any of the partitions might be empty, in which case the
259 * pointer to that partition will be equal to the pointer for
260 * the following partition. When the list is empty, all of
261 * the nxttail elements point to the ->nxtlist pointer itself,
262 * which in that case is NULL.
263 *
264 * [nxtlist, *nxttail[RCU_DONE_TAIL]):
265 * Entries that batch # <= ->completed
266 * The grace period for these entries has completed, and
267 * the other grace-period-completed entries may be moved
268 * here temporarily in rcu_process_callbacks().
269 * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
270 * Entries that batch # <= ->completed - 1: waiting for current GP
271 * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
272 * Entries known to have arrived before current GP ended
273 * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]):
274 * Entries that might have arrived after current GP ended
275 * Note that the value of *nxttail[RCU_NEXT_TAIL] will
276 * always be NULL, as this is the end of the list.
277 */
278 struct rcu_head *nxtlist;
279 struct rcu_head **nxttail[RCU_NEXT_SIZE];
280 unsigned long nxtcompleted[RCU_NEXT_SIZE];
281 /* grace periods for sublists. */
282 long qlen_lazy; /* # of lazy queued callbacks */
283 long qlen; /* # of queued callbacks, incl lazy */
284 long qlen_last_fqs_check;
285 /* qlen at last check for QS forcing */
286 unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */
287 unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */
288 unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */
289 unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */
290 unsigned long n_force_qs_snap;
291 /* did other CPU force QS recently? */
292 long blimit; /* Upper limit on a processed batch */
293
294 /* 3) dynticks interface. */
295 struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */
296 int dynticks_snap; /* Per-GP tracking for dynticks. */
297
298 /* 4) reasons this CPU needed to be kicked by force_quiescent_state */
299 unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */
300 unsigned long offline_fqs; /* Kicked due to being offline. */
301
302 /* 5) __rcu_pending() statistics. */
303 unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */
304 unsigned long n_rp_qs_pending;
305 unsigned long n_rp_report_qs;
306 unsigned long n_rp_cb_ready;
307 unsigned long n_rp_cpu_needs_gp;
308 unsigned long n_rp_gp_completed;
309 unsigned long n_rp_gp_started;
310 unsigned long n_rp_need_nothing;
311
312 /* 6) _rcu_barrier() and OOM callbacks. */
313 struct rcu_head barrier_head;
314 #ifdef CONFIG_RCU_FAST_NO_HZ
315 struct rcu_head oom_head;
316 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
317
318 /* 7) Callback offloading. */
319 #ifdef CONFIG_RCU_NOCB_CPU
320 struct rcu_head *nocb_head; /* CBs waiting for kthread. */
321 struct rcu_head **nocb_tail;
322 atomic_long_t nocb_q_count; /* # CBs waiting for kthread */
323 atomic_long_t nocb_q_count_lazy; /* (approximate). */
324 int nocb_p_count; /* # CBs being invoked by kthread */
325 int nocb_p_count_lazy; /* (approximate). */
326 wait_queue_head_t nocb_wq; /* For nocb kthreads to sleep on. */
327 struct task_struct *nocb_kthread;
328 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */
329
330 /* 8) RCU CPU stall data. */
331 #ifdef CONFIG_RCU_CPU_STALL_INFO
332 unsigned int softirq_snap; /* Snapshot of softirq activity. */
333 #endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
334
335 int cpu;
336 struct rcu_state *rsp;
337 };
338
339 /* Values for fqs_state field in struct rcu_state. */
340 #define RCU_GP_IDLE 0 /* No grace period in progress. */
341 #define RCU_GP_INIT 1 /* Grace period being initialized. */
342 #define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */
343 #define RCU_FORCE_QS 3 /* Need to force quiescent state. */
344 #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK
345
346 #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */
347
348 #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time */
349 /* to take at least one */
350 /* scheduling clock irq */
351 /* before ratting on them. */
352
353 #define rcu_wait(cond) \
354 do { \
355 for (;;) { \
356 set_current_state(TASK_INTERRUPTIBLE); \
357 if (cond) \
358 break; \
359 schedule(); \
360 } \
361 __set_current_state(TASK_RUNNING); \
362 } while (0)
363
364 /*
365 * RCU global state, including node hierarchy. This hierarchy is
366 * represented in "heap" form in a dense array. The root (first level)
367 * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
368 * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
369 * and the third level in ->node[m+1] and following (->node[m+1] referenced
370 * by ->level[2]). The number of levels is determined by the number of
371 * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy"
372 * consisting of a single rcu_node.
373 */
374 struct rcu_state {
375 struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
376 struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */
377 u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */
378 u8 levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */
379 struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */
380 void (*call)(struct rcu_head *head, /* call_rcu() flavor. */
381 void (*func)(struct rcu_head *head));
382
383 /* The following fields are guarded by the root rcu_node's lock. */
384
385 u8 fqs_state ____cacheline_internodealigned_in_smp;
386 /* Force QS state. */
387 u8 boost; /* Subject to priority boost. */
388 unsigned long gpnum; /* Current gp number. */
389 unsigned long completed; /* # of last completed gp. */
390 struct task_struct *gp_kthread; /* Task for grace periods. */
391 wait_queue_head_t gp_wq; /* Where GP task waits. */
392 int gp_flags; /* Commands for GP task. */
393
394 /* End of fields guarded by root rcu_node's lock. */
395
396 raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp;
397 /* Protect following fields. */
398 struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */
399 /* need a grace period. */
400 struct rcu_head **orphan_nxttail; /* Tail of above. */
401 struct rcu_head *orphan_donelist; /* Orphaned callbacks that */
402 /* are ready to invoke. */
403 struct rcu_head **orphan_donetail; /* Tail of above. */
404 long qlen_lazy; /* Number of lazy callbacks. */
405 long qlen; /* Total number of callbacks. */
406 /* End of fields guarded by orphan_lock. */
407
408 struct mutex onoff_mutex; /* Coordinate hotplug & GPs. */
409
410 struct mutex barrier_mutex; /* Guards barrier fields. */
411 atomic_t barrier_cpu_count; /* # CPUs waiting on. */
412 struct completion barrier_completion; /* Wake at barrier end. */
413 unsigned long n_barrier_done; /* ++ at start and end of */
414 /* _rcu_barrier(). */
415 /* End of fields guarded by barrier_mutex. */
416
417 atomic_long_t expedited_start; /* Starting ticket. */
418 atomic_long_t expedited_done; /* Done ticket. */
419 atomic_long_t expedited_wrap; /* # near-wrap incidents. */
420 atomic_long_t expedited_tryfail; /* # acquisition failures. */
421 atomic_long_t expedited_workdone1; /* # done by others #1. */
422 atomic_long_t expedited_workdone2; /* # done by others #2. */
423 atomic_long_t expedited_normal; /* # fallbacks to normal. */
424 atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */
425 atomic_long_t expedited_done_tries; /* # tries to update _done. */
426 atomic_long_t expedited_done_lost; /* # times beaten to _done. */
427 atomic_long_t expedited_done_exit; /* # times exited _done loop. */
428
429 unsigned long jiffies_force_qs; /* Time at which to invoke */
430 /* force_quiescent_state(). */
431 unsigned long n_force_qs; /* Number of calls to */
432 /* force_quiescent_state(). */
433 unsigned long n_force_qs_lh; /* ~Number of calls leaving */
434 /* due to lock unavailable. */
435 unsigned long n_force_qs_ngp; /* Number of calls leaving */
436 /* due to no GP active. */
437 unsigned long gp_start; /* Time at which GP started, */
438 /* but in jiffies. */
439 unsigned long jiffies_stall; /* Time at which to check */
440 /* for CPU stalls. */
441 unsigned long gp_max; /* Maximum GP duration in */
442 /* jiffies. */
443 char *name; /* Name of structure. */
444 char abbr; /* Abbreviated name. */
445 struct list_head flavors; /* List of RCU flavors. */
446 struct irq_work wakeup_work; /* Postponed wakeups */
447 };
448
449 /* Values for rcu_state structure's gp_flags field. */
450 #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */
451 #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */
452
453 extern struct list_head rcu_struct_flavors;
454
455 /* Sequence through rcu_state structures for each RCU flavor. */
456 #define for_each_rcu_flavor(rsp) \
457 list_for_each_entry((rsp), &rcu_struct_flavors, flavors)
458
459 /* Return values for rcu_preempt_offline_tasks(). */
460
461 #define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */
462 /* GP were moved to root. */
463 #define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */
464 /* GP were moved to root. */
465
466 /*
467 * RCU implementation internal declarations:
468 */
469 extern struct rcu_state rcu_sched_state;
470 DECLARE_PER_CPU(struct rcu_data, rcu_sched_data);
471
472 extern struct rcu_state rcu_bh_state;
473 DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
474
475 #ifdef CONFIG_TREE_PREEMPT_RCU
476 extern struct rcu_state rcu_preempt_state;
477 DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
478 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
479
480 #ifdef CONFIG_RCU_BOOST
481 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
482 DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
483 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
484 DECLARE_PER_CPU(char, rcu_cpu_has_work);
485 #endif /* #ifdef CONFIG_RCU_BOOST */
486
487 #ifndef RCU_TREE_NONCORE
488
489 /* Forward declarations for rcutree_plugin.h */
490 static void rcu_bootup_announce(void);
491 long rcu_batches_completed(void);
492 static void rcu_preempt_note_context_switch(int cpu);
493 static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
494 #ifdef CONFIG_HOTPLUG_CPU
495 static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
496 unsigned long flags);
497 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
498 static void rcu_print_detail_task_stall(struct rcu_state *rsp);
499 static int rcu_print_task_stall(struct rcu_node *rnp);
500 static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
501 #ifdef CONFIG_HOTPLUG_CPU
502 static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
503 struct rcu_node *rnp,
504 struct rcu_data *rdp);
505 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
506 static void rcu_preempt_check_callbacks(int cpu);
507 void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
508 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU)
509 static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
510 bool wake);
511 #endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */
512 static void __init __rcu_init_preempt(void);
513 static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
514 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
515 static void invoke_rcu_callbacks_kthread(void);
516 static bool rcu_is_callbacks_kthread(void);
517 #ifdef CONFIG_RCU_BOOST
518 static void rcu_preempt_do_callbacks(void);
519 static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
520 struct rcu_node *rnp);
521 #endif /* #ifdef CONFIG_RCU_BOOST */
522 static void __cpuinit rcu_prepare_kthreads(int cpu);
523 static void rcu_cleanup_after_idle(int cpu);
524 static void rcu_prepare_for_idle(int cpu);
525 static void rcu_idle_count_callbacks_posted(void);
526 static void print_cpu_stall_info_begin(void);
527 static void print_cpu_stall_info(struct rcu_state *rsp, int cpu);
528 static void print_cpu_stall_info_end(void);
529 static void zero_cpu_stall_ticks(struct rcu_data *rdp);
530 static void increment_cpu_stall_ticks(void);
531 static int rcu_nocb_needs_gp(struct rcu_state *rsp);
532 static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq);
533 static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp);
534 static void rcu_init_one_nocb(struct rcu_node *rnp);
535 static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
536 bool lazy);
537 static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
538 struct rcu_data *rdp);
539 static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
540 static void rcu_spawn_nocb_kthreads(struct rcu_state *rsp);
541 static void rcu_kick_nohz_cpu(int cpu);
542 static bool init_nocb_callback_list(struct rcu_data *rdp);
543
544 #endif /* #ifndef RCU_TREE_NONCORE */
545
546 #ifdef CONFIG_RCU_TRACE
547 #ifdef CONFIG_RCU_NOCB_CPU
548 /* Sum up queue lengths for tracing. */
rcu_nocb_q_lengths(struct rcu_data * rdp,long * ql,long * qll)549 static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
550 {
551 *ql = atomic_long_read(&rdp->nocb_q_count) + rdp->nocb_p_count;
552 *qll = atomic_long_read(&rdp->nocb_q_count_lazy) + rdp->nocb_p_count_lazy;
553 }
554 #else /* #ifdef CONFIG_RCU_NOCB_CPU */
rcu_nocb_q_lengths(struct rcu_data * rdp,long * ql,long * qll)555 static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
556 {
557 *ql = 0;
558 *qll = 0;
559 }
560 #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
561 #endif /* #ifdef CONFIG_RCU_TRACE */
562