Root/
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 (1 + (HZ > 250) + (HZ > 500)) |
347 | /* For jiffies_till_first_fqs and */ |
348 | /* and jiffies_till_next_fqs. */ |
349 | |
350 | #define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */ |
351 | /* delay between bouts of */ |
352 | /* quiescent-state forcing. */ |
353 | |
354 | #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */ |
355 | /* at least one scheduling clock */ |
356 | /* irq before ratting on them. */ |
357 | |
358 | #define rcu_wait(cond) \ |
359 | do { \ |
360 | for (;;) { \ |
361 | set_current_state(TASK_INTERRUPTIBLE); \ |
362 | if (cond) \ |
363 | break; \ |
364 | schedule(); \ |
365 | } \ |
366 | __set_current_state(TASK_RUNNING); \ |
367 | } while (0) |
368 | |
369 | /* |
370 | * RCU global state, including node hierarchy. This hierarchy is |
371 | * represented in "heap" form in a dense array. The root (first level) |
372 | * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second |
373 | * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), |
374 | * and the third level in ->node[m+1] and following (->node[m+1] referenced |
375 | * by ->level[2]). The number of levels is determined by the number of |
376 | * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" |
377 | * consisting of a single rcu_node. |
378 | */ |
379 | struct rcu_state { |
380 | struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ |
381 | struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */ |
382 | u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */ |
383 | u8 levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */ |
384 | struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ |
385 | void (*call)(struct rcu_head *head, /* call_rcu() flavor. */ |
386 | void (*func)(struct rcu_head *head)); |
387 | |
388 | /* The following fields are guarded by the root rcu_node's lock. */ |
389 | |
390 | u8 fqs_state ____cacheline_internodealigned_in_smp; |
391 | /* Force QS state. */ |
392 | u8 boost; /* Subject to priority boost. */ |
393 | unsigned long gpnum; /* Current gp number. */ |
394 | unsigned long completed; /* # of last completed gp. */ |
395 | struct task_struct *gp_kthread; /* Task for grace periods. */ |
396 | wait_queue_head_t gp_wq; /* Where GP task waits. */ |
397 | int gp_flags; /* Commands for GP task. */ |
398 | |
399 | /* End of fields guarded by root rcu_node's lock. */ |
400 | |
401 | raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp; |
402 | /* Protect following fields. */ |
403 | struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */ |
404 | /* need a grace period. */ |
405 | struct rcu_head **orphan_nxttail; /* Tail of above. */ |
406 | struct rcu_head *orphan_donelist; /* Orphaned callbacks that */ |
407 | /* are ready to invoke. */ |
408 | struct rcu_head **orphan_donetail; /* Tail of above. */ |
409 | long qlen_lazy; /* Number of lazy callbacks. */ |
410 | long qlen; /* Total number of callbacks. */ |
411 | /* End of fields guarded by orphan_lock. */ |
412 | |
413 | struct mutex onoff_mutex; /* Coordinate hotplug & GPs. */ |
414 | |
415 | struct mutex barrier_mutex; /* Guards barrier fields. */ |
416 | atomic_t barrier_cpu_count; /* # CPUs waiting on. */ |
417 | struct completion barrier_completion; /* Wake at barrier end. */ |
418 | unsigned long n_barrier_done; /* ++ at start and end of */ |
419 | /* _rcu_barrier(). */ |
420 | /* End of fields guarded by barrier_mutex. */ |
421 | |
422 | atomic_long_t expedited_start; /* Starting ticket. */ |
423 | atomic_long_t expedited_done; /* Done ticket. */ |
424 | atomic_long_t expedited_wrap; /* # near-wrap incidents. */ |
425 | atomic_long_t expedited_tryfail; /* # acquisition failures. */ |
426 | atomic_long_t expedited_workdone1; /* # done by others #1. */ |
427 | atomic_long_t expedited_workdone2; /* # done by others #2. */ |
428 | atomic_long_t expedited_normal; /* # fallbacks to normal. */ |
429 | atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */ |
430 | atomic_long_t expedited_done_tries; /* # tries to update _done. */ |
431 | atomic_long_t expedited_done_lost; /* # times beaten to _done. */ |
432 | atomic_long_t expedited_done_exit; /* # times exited _done loop. */ |
433 | |
434 | unsigned long jiffies_force_qs; /* Time at which to invoke */ |
435 | /* force_quiescent_state(). */ |
436 | unsigned long n_force_qs; /* Number of calls to */ |
437 | /* force_quiescent_state(). */ |
438 | unsigned long n_force_qs_lh; /* ~Number of calls leaving */ |
439 | /* due to lock unavailable. */ |
440 | unsigned long n_force_qs_ngp; /* Number of calls leaving */ |
441 | /* due to no GP active. */ |
442 | unsigned long gp_start; /* Time at which GP started, */ |
443 | /* but in jiffies. */ |
444 | unsigned long jiffies_stall; /* Time at which to check */ |
445 | /* for CPU stalls. */ |
446 | unsigned long gp_max; /* Maximum GP duration in */ |
447 | /* jiffies. */ |
448 | char *name; /* Name of structure. */ |
449 | char abbr; /* Abbreviated name. */ |
450 | struct list_head flavors; /* List of RCU flavors. */ |
451 | struct irq_work wakeup_work; /* Postponed wakeups */ |
452 | }; |
453 | |
454 | /* Values for rcu_state structure's gp_flags field. */ |
455 | #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ |
456 | #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ |
457 | |
458 | extern struct list_head rcu_struct_flavors; |
459 | |
460 | /* Sequence through rcu_state structures for each RCU flavor. */ |
461 | #define for_each_rcu_flavor(rsp) \ |
462 | list_for_each_entry((rsp), &rcu_struct_flavors, flavors) |
463 | |
464 | /* Return values for rcu_preempt_offline_tasks(). */ |
465 | |
466 | #define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */ |
467 | /* GP were moved to root. */ |
468 | #define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */ |
469 | /* GP were moved to root. */ |
470 | |
471 | /* |
472 | * RCU implementation internal declarations: |
473 | */ |
474 | extern struct rcu_state rcu_sched_state; |
475 | DECLARE_PER_CPU(struct rcu_data, rcu_sched_data); |
476 | |
477 | extern struct rcu_state rcu_bh_state; |
478 | DECLARE_PER_CPU(struct rcu_data, rcu_bh_data); |
479 | |
480 | #ifdef CONFIG_TREE_PREEMPT_RCU |
481 | extern struct rcu_state rcu_preempt_state; |
482 | DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); |
483 | #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ |
484 | |
485 | #ifdef CONFIG_RCU_BOOST |
486 | DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); |
487 | DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); |
488 | DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); |
489 | DECLARE_PER_CPU(char, rcu_cpu_has_work); |
490 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
491 | |
492 | #ifndef RCU_TREE_NONCORE |
493 | |
494 | /* Forward declarations for rcutree_plugin.h */ |
495 | static void rcu_bootup_announce(void); |
496 | long rcu_batches_completed(void); |
497 | static void rcu_preempt_note_context_switch(int cpu); |
498 | static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); |
499 | #ifdef CONFIG_HOTPLUG_CPU |
500 | static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, |
501 | unsigned long flags); |
502 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
503 | static void rcu_print_detail_task_stall(struct rcu_state *rsp); |
504 | static int rcu_print_task_stall(struct rcu_node *rnp); |
505 | static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); |
506 | #ifdef CONFIG_HOTPLUG_CPU |
507 | static int rcu_preempt_offline_tasks(struct rcu_state *rsp, |
508 | struct rcu_node *rnp, |
509 | struct rcu_data *rdp); |
510 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
511 | static void rcu_preempt_check_callbacks(int cpu); |
512 | void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); |
513 | #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) |
514 | static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, |
515 | bool wake); |
516 | #endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */ |
517 | static void __init __rcu_init_preempt(void); |
518 | static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); |
519 | static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); |
520 | static void invoke_rcu_callbacks_kthread(void); |
521 | static bool rcu_is_callbacks_kthread(void); |
522 | #ifdef CONFIG_RCU_BOOST |
523 | static void rcu_preempt_do_callbacks(void); |
524 | static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, |
525 | struct rcu_node *rnp); |
526 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
527 | static void rcu_prepare_kthreads(int cpu); |
528 | static void rcu_cleanup_after_idle(int cpu); |
529 | static void rcu_prepare_for_idle(int cpu); |
530 | static void rcu_idle_count_callbacks_posted(void); |
531 | static void print_cpu_stall_info_begin(void); |
532 | static void print_cpu_stall_info(struct rcu_state *rsp, int cpu); |
533 | static void print_cpu_stall_info_end(void); |
534 | static void zero_cpu_stall_ticks(struct rcu_data *rdp); |
535 | static void increment_cpu_stall_ticks(void); |
536 | static int rcu_nocb_needs_gp(struct rcu_state *rsp); |
537 | static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq); |
538 | static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp); |
539 | static void rcu_init_one_nocb(struct rcu_node *rnp); |
540 | static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, |
541 | bool lazy); |
542 | static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, |
543 | struct rcu_data *rdp); |
544 | static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); |
545 | static void rcu_spawn_nocb_kthreads(struct rcu_state *rsp); |
546 | static void rcu_kick_nohz_cpu(int cpu); |
547 | static bool init_nocb_callback_list(struct rcu_data *rdp); |
548 | |
549 | #endif /* #ifndef RCU_TREE_NONCORE */ |
550 | |
551 | #ifdef CONFIG_RCU_TRACE |
552 | #ifdef CONFIG_RCU_NOCB_CPU |
553 | /* Sum up queue lengths for tracing. */ |
554 | static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) |
555 | { |
556 | *ql = atomic_long_read(&rdp->nocb_q_count) + rdp->nocb_p_count; |
557 | *qll = atomic_long_read(&rdp->nocb_q_count_lazy) + rdp->nocb_p_count_lazy; |
558 | } |
559 | #else /* #ifdef CONFIG_RCU_NOCB_CPU */ |
560 | static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) |
561 | { |
562 | *ql = 0; |
563 | *qll = 0; |
564 | } |
565 | #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ |
566 | #endif /* #ifdef CONFIG_RCU_TRACE */ |
567 |
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