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9f77da9f PM |
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 | ||
31 | /* | |
8932a63d PM |
32 | * Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and |
33 | * CONFIG_RCU_FANOUT_LEAF. | |
9f77da9f | 34 | * In theory, it should be possible to add more levels straightforwardly. |
0209f649 PM |
35 | * In practice, this did work well going from three levels to four. |
36 | * Of course, your mileage may vary. | |
9f77da9f | 37 | */ |
cf244dc0 | 38 | #define MAX_RCU_LVLS 4 |
8932a63d | 39 | #define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF) |
0209f649 PM |
40 | #define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT) |
41 | #define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT) | |
42 | #define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT) | |
9f77da9f | 43 | |
0209f649 | 44 | #if NR_CPUS <= RCU_FANOUT_1 |
f885b7f2 | 45 | # define RCU_NUM_LVLS 1 |
9f77da9f PM |
46 | # define NUM_RCU_LVL_0 1 |
47 | # define NUM_RCU_LVL_1 (NR_CPUS) | |
48 | # define NUM_RCU_LVL_2 0 | |
49 | # define NUM_RCU_LVL_3 0 | |
cf244dc0 | 50 | # define NUM_RCU_LVL_4 0 |
0209f649 | 51 | #elif NR_CPUS <= RCU_FANOUT_2 |
f885b7f2 | 52 | # define RCU_NUM_LVLS 2 |
9f77da9f | 53 | # define NUM_RCU_LVL_0 1 |
0209f649 | 54 | # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) |
9f77da9f PM |
55 | # define NUM_RCU_LVL_2 (NR_CPUS) |
56 | # define NUM_RCU_LVL_3 0 | |
cf244dc0 | 57 | # define NUM_RCU_LVL_4 0 |
0209f649 | 58 | #elif NR_CPUS <= RCU_FANOUT_3 |
f885b7f2 | 59 | # define RCU_NUM_LVLS 3 |
9f77da9f | 60 | # define NUM_RCU_LVL_0 1 |
0209f649 PM |
61 | # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2) |
62 | # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) | |
63 | # define NUM_RCU_LVL_3 (NR_CPUS) | |
cf244dc0 | 64 | # define NUM_RCU_LVL_4 0 |
0209f649 | 65 | #elif NR_CPUS <= RCU_FANOUT_4 |
f885b7f2 | 66 | # define RCU_NUM_LVLS 4 |
cf244dc0 | 67 | # define NUM_RCU_LVL_0 1 |
0209f649 PM |
68 | # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3) |
69 | # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2) | |
70 | # define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) | |
71 | # define NUM_RCU_LVL_4 (NR_CPUS) | |
9f77da9f PM |
72 | #else |
73 | # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS" | |
0209f649 | 74 | #endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */ |
9f77da9f | 75 | |
cf244dc0 | 76 | #define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4) |
9f77da9f PM |
77 | #define NUM_RCU_NODES (RCU_SUM - NR_CPUS) |
78 | ||
f885b7f2 PM |
79 | extern int rcu_num_lvls; |
80 | extern int rcu_num_nodes; | |
81 | ||
9f77da9f PM |
82 | /* |
83 | * Dynticks per-CPU state. | |
84 | */ | |
85 | struct rcu_dynticks { | |
9b2e4f18 PM |
86 | long long dynticks_nesting; /* Track irq/process nesting level. */ |
87 | /* Process level is worth LLONG_MAX/2. */ | |
88 | int dynticks_nmi_nesting; /* Track NMI nesting level. */ | |
89 | atomic_t dynticks; /* Even value for idle, else odd. */ | |
5955f7ee PM |
90 | #ifdef CONFIG_RCU_FAST_NO_HZ |
91 | int dyntick_drain; /* Prepare-for-idle state variable. */ | |
92 | unsigned long dyntick_holdoff; | |
93 | /* No retries for the jiffy of failure. */ | |
94 | struct timer_list idle_gp_timer; | |
95 | /* Wake up CPU sleeping with callbacks. */ | |
96 | unsigned long idle_gp_timer_expires; | |
97 | /* When to wake up CPU (for repost). */ | |
98 | bool idle_first_pass; /* First pass of attempt to go idle? */ | |
99 | unsigned long nonlazy_posted; | |
100 | /* # times non-lazy CBs posted to CPU. */ | |
101 | unsigned long nonlazy_posted_snap; | |
102 | /* idle-period nonlazy_posted snapshot. */ | |
9d2ad243 | 103 | int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */ |
5955f7ee | 104 | #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ |
c5d900bf | 105 | #ifdef CONFIG_RCU_USER_QS |
1e1a689f | 106 | bool ignore_user_qs; /* Treat userspace as extended QS or not */ |
c5d900bf FW |
107 | bool in_user; /* Is the CPU in userland from RCU POV? */ |
108 | #endif | |
9f77da9f PM |
109 | }; |
110 | ||
d71df90e PM |
111 | /* RCU's kthread states for tracing. */ |
112 | #define RCU_KTHREAD_STOPPED 0 | |
113 | #define RCU_KTHREAD_RUNNING 1 | |
114 | #define RCU_KTHREAD_WAITING 2 | |
15ba0ba8 PM |
115 | #define RCU_KTHREAD_OFFCPU 3 |
116 | #define RCU_KTHREAD_YIELDING 4 | |
117 | #define RCU_KTHREAD_MAX 4 | |
d71df90e | 118 | |
9f77da9f PM |
119 | /* |
120 | * Definition for node within the RCU grace-period-detection hierarchy. | |
121 | */ | |
122 | struct rcu_node { | |
1304afb2 | 123 | raw_spinlock_t lock; /* Root rcu_node's lock protects some */ |
1eba8f84 | 124 | /* rcu_state fields as well as following. */ |
20133cfc | 125 | unsigned long gpnum; /* Current grace period for this node. */ |
86848966 PM |
126 | /* This will either be equal to or one */ |
127 | /* behind the root rcu_node's gpnum. */ | |
20133cfc | 128 | unsigned long completed; /* Last GP completed for this node. */ |
d09b62df PM |
129 | /* This will either be equal to or one */ |
130 | /* behind the root rcu_node's gpnum. */ | |
9f77da9f PM |
131 | unsigned long qsmask; /* CPUs or groups that need to switch in */ |
132 | /* order for current grace period to proceed.*/ | |
1eba8f84 PM |
133 | /* In leaf rcu_node, each bit corresponds to */ |
134 | /* an rcu_data structure, otherwise, each */ | |
135 | /* bit corresponds to a child rcu_node */ | |
136 | /* structure. */ | |
12f5f524 | 137 | unsigned long expmask; /* Groups that have ->blkd_tasks */ |
d9a3da06 PM |
138 | /* elements that need to drain to allow the */ |
139 | /* current expedited grace period to */ | |
140 | /* complete (only for TREE_PREEMPT_RCU). */ | |
8826f3b0 PM |
141 | atomic_t wakemask; /* CPUs whose kthread needs to be awakened. */ |
142 | /* Since this has meaning only for leaf */ | |
143 | /* rcu_node structures, 32 bits suffices. */ | |
9f77da9f | 144 | unsigned long qsmaskinit; |
d9a3da06 | 145 | /* Per-GP initial value for qsmask & expmask. */ |
9f77da9f | 146 | unsigned long grpmask; /* Mask to apply to parent qsmask. */ |
1eba8f84 | 147 | /* Only one bit will be set in this mask. */ |
9f77da9f PM |
148 | int grplo; /* lowest-numbered CPU or group here. */ |
149 | int grphi; /* highest-numbered CPU or group here. */ | |
150 | u8 grpnum; /* CPU/group number for next level up. */ | |
151 | u8 level; /* root is at level 0. */ | |
152 | struct rcu_node *parent; | |
12f5f524 PM |
153 | struct list_head blkd_tasks; |
154 | /* Tasks blocked in RCU read-side critical */ | |
155 | /* section. Tasks are placed at the head */ | |
156 | /* of this list and age towards the tail. */ | |
157 | struct list_head *gp_tasks; | |
158 | /* Pointer to the first task blocking the */ | |
159 | /* current grace period, or NULL if there */ | |
160 | /* is no such task. */ | |
161 | struct list_head *exp_tasks; | |
162 | /* Pointer to the first task blocking the */ | |
163 | /* current expedited grace period, or NULL */ | |
164 | /* if there is no such task. If there */ | |
165 | /* is no current expedited grace period, */ | |
166 | /* then there can cannot be any such task. */ | |
27f4d280 PM |
167 | #ifdef CONFIG_RCU_BOOST |
168 | struct list_head *boost_tasks; | |
169 | /* Pointer to first task that needs to be */ | |
170 | /* priority boosted, or NULL if no priority */ | |
171 | /* boosting is needed for this rcu_node */ | |
172 | /* structure. If there are no tasks */ | |
173 | /* queued on this rcu_node structure that */ | |
174 | /* are blocking the current grace period, */ | |
175 | /* there can be no such task. */ | |
176 | unsigned long boost_time; | |
177 | /* When to start boosting (jiffies). */ | |
178 | struct task_struct *boost_kthread_task; | |
179 | /* kthread that takes care of priority */ | |
180 | /* boosting for this rcu_node structure. */ | |
d71df90e PM |
181 | unsigned int boost_kthread_status; |
182 | /* State of boost_kthread_task for tracing. */ | |
0ea1f2eb PM |
183 | unsigned long n_tasks_boosted; |
184 | /* Total number of tasks boosted. */ | |
185 | unsigned long n_exp_boosts; | |
186 | /* Number of tasks boosted for expedited GP. */ | |
187 | unsigned long n_normal_boosts; | |
188 | /* Number of tasks boosted for normal GP. */ | |
189 | unsigned long n_balk_blkd_tasks; | |
190 | /* Refused to boost: no blocked tasks. */ | |
191 | unsigned long n_balk_exp_gp_tasks; | |
192 | /* Refused to boost: nothing blocking GP. */ | |
193 | unsigned long n_balk_boost_tasks; | |
194 | /* Refused to boost: already boosting. */ | |
195 | unsigned long n_balk_notblocked; | |
196 | /* Refused to boost: RCU RS CS still running. */ | |
197 | unsigned long n_balk_notyet; | |
198 | /* Refused to boost: not yet time. */ | |
199 | unsigned long n_balk_nos; | |
200 | /* Refused to boost: not sure why, though. */ | |
201 | /* This can happen due to race conditions. */ | |
27f4d280 | 202 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
394f2769 | 203 | raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp; |
9f77da9f PM |
204 | } ____cacheline_internodealigned_in_smp; |
205 | ||
a0b6c9a7 PM |
206 | /* |
207 | * Do a full breadth-first scan of the rcu_node structures for the | |
208 | * specified rcu_state structure. | |
209 | */ | |
210 | #define rcu_for_each_node_breadth_first(rsp, rnp) \ | |
211 | for ((rnp) = &(rsp)->node[0]; \ | |
f885b7f2 | 212 | (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) |
a0b6c9a7 | 213 | |
d9a3da06 PM |
214 | /* |
215 | * Do a breadth-first scan of the non-leaf rcu_node structures for the | |
216 | * specified rcu_state structure. Note that if there is a singleton | |
217 | * rcu_node tree with but one rcu_node structure, this loop is a no-op. | |
218 | */ | |
219 | #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ | |
220 | for ((rnp) = &(rsp)->node[0]; \ | |
f885b7f2 | 221 | (rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++) |
d9a3da06 PM |
222 | |
223 | /* | |
224 | * Scan the leaves of the rcu_node hierarchy for the specified rcu_state | |
225 | * structure. Note that if there is a singleton rcu_node tree with but | |
226 | * one rcu_node structure, this loop -will- visit the rcu_node structure. | |
227 | * It is still a leaf node, even if it is also the root node. | |
228 | */ | |
a0b6c9a7 | 229 | #define rcu_for_each_leaf_node(rsp, rnp) \ |
f885b7f2 PM |
230 | for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \ |
231 | (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) | |
a0b6c9a7 | 232 | |
9f77da9f PM |
233 | /* Index values for nxttail array in struct rcu_data. */ |
234 | #define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */ | |
235 | #define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */ | |
236 | #define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */ | |
237 | #define RCU_NEXT_TAIL 3 | |
238 | #define RCU_NEXT_SIZE 4 | |
239 | ||
240 | /* Per-CPU data for read-copy update. */ | |
241 | struct rcu_data { | |
242 | /* 1) quiescent-state and grace-period handling : */ | |
20133cfc | 243 | unsigned long completed; /* Track rsp->completed gp number */ |
9f77da9f | 244 | /* in order to detect GP end. */ |
20133cfc | 245 | unsigned long gpnum; /* Highest gp number that this CPU */ |
9f77da9f | 246 | /* is aware of having started. */ |
e4cc1f22 | 247 | bool passed_quiesce; /* User-mode/idle loop etc. */ |
9f77da9f PM |
248 | bool qs_pending; /* Core waits for quiesc state. */ |
249 | bool beenonline; /* CPU online at least once. */ | |
6cc68793 | 250 | bool preemptible; /* Preemptible RCU? */ |
9f77da9f PM |
251 | struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ |
252 | unsigned long grpmask; /* Mask to apply to leaf qsmask. */ | |
a858af28 PM |
253 | #ifdef CONFIG_RCU_CPU_STALL_INFO |
254 | unsigned long ticks_this_gp; /* The number of scheduling-clock */ | |
255 | /* ticks this CPU has handled */ | |
256 | /* during and after the last grace */ | |
257 | /* period it is aware of. */ | |
258 | #endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */ | |
9f77da9f PM |
259 | |
260 | /* 2) batch handling */ | |
261 | /* | |
262 | * If nxtlist is not NULL, it is partitioned as follows. | |
263 | * Any of the partitions might be empty, in which case the | |
264 | * pointer to that partition will be equal to the pointer for | |
265 | * the following partition. When the list is empty, all of | |
1eba8f84 PM |
266 | * the nxttail elements point to the ->nxtlist pointer itself, |
267 | * which in that case is NULL. | |
9f77da9f | 268 | * |
9f77da9f PM |
269 | * [nxtlist, *nxttail[RCU_DONE_TAIL]): |
270 | * Entries that batch # <= ->completed | |
271 | * The grace period for these entries has completed, and | |
272 | * the other grace-period-completed entries may be moved | |
273 | * here temporarily in rcu_process_callbacks(). | |
1eba8f84 PM |
274 | * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]): |
275 | * Entries that batch # <= ->completed - 1: waiting for current GP | |
276 | * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]): | |
277 | * Entries known to have arrived before current GP ended | |
278 | * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]): | |
279 | * Entries that might have arrived after current GP ended | |
280 | * Note that the value of *nxttail[RCU_NEXT_TAIL] will | |
281 | * always be NULL, as this is the end of the list. | |
9f77da9f PM |
282 | */ |
283 | struct rcu_head *nxtlist; | |
284 | struct rcu_head **nxttail[RCU_NEXT_SIZE]; | |
486e2593 PM |
285 | long qlen_lazy; /* # of lazy queued callbacks */ |
286 | long qlen; /* # of queued callbacks, incl lazy */ | |
37c72e56 PM |
287 | long qlen_last_fqs_check; |
288 | /* qlen at last check for QS forcing */ | |
269dcc1c | 289 | unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ |
c635a4e1 | 290 | unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */ |
29494be7 LJ |
291 | unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */ |
292 | unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */ | |
37c72e56 PM |
293 | unsigned long n_force_qs_snap; |
294 | /* did other CPU force QS recently? */ | |
9f77da9f PM |
295 | long blimit; /* Upper limit on a processed batch */ |
296 | ||
9f77da9f PM |
297 | /* 3) dynticks interface. */ |
298 | struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ | |
299 | int dynticks_snap; /* Per-GP tracking for dynticks. */ | |
9f77da9f PM |
300 | |
301 | /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ | |
9f77da9f | 302 | unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */ |
9f77da9f | 303 | unsigned long offline_fqs; /* Kicked due to being offline. */ |
9f77da9f PM |
304 | |
305 | /* 5) __rcu_pending() statistics. */ | |
20133cfc PM |
306 | unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ |
307 | unsigned long n_rp_qs_pending; | |
d21670ac | 308 | unsigned long n_rp_report_qs; |
20133cfc PM |
309 | unsigned long n_rp_cb_ready; |
310 | unsigned long n_rp_cpu_needs_gp; | |
311 | unsigned long n_rp_gp_completed; | |
312 | unsigned long n_rp_gp_started; | |
20133cfc | 313 | unsigned long n_rp_need_nothing; |
9f77da9f | 314 | |
b626c1b6 | 315 | /* 6) _rcu_barrier() and OOM callbacks. */ |
06668efa | 316 | struct rcu_head barrier_head; |
b626c1b6 PM |
317 | #ifdef CONFIG_RCU_FAST_NO_HZ |
318 | struct rcu_head oom_head; | |
319 | #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ | |
06668efa | 320 | |
3fbfbf7a PM |
321 | /* 7) Callback offloading. */ |
322 | #ifdef CONFIG_RCU_NOCB_CPU | |
323 | struct rcu_head *nocb_head; /* CBs waiting for kthread. */ | |
324 | struct rcu_head **nocb_tail; | |
325 | atomic_long_t nocb_q_count; /* # CBs waiting for kthread */ | |
326 | atomic_long_t nocb_q_count_lazy; /* (approximate). */ | |
327 | int nocb_p_count; /* # CBs being invoked by kthread */ | |
328 | int nocb_p_count_lazy; /* (approximate). */ | |
329 | wait_queue_head_t nocb_wq; /* For nocb kthreads to sleep on. */ | |
330 | struct task_struct *nocb_kthread; | |
331 | #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ | |
332 | ||
9f77da9f | 333 | int cpu; |
d4c08f2a | 334 | struct rcu_state *rsp; |
9f77da9f PM |
335 | }; |
336 | ||
af446b70 | 337 | /* Values for fqs_state field in struct rcu_state. */ |
83f5b01f PM |
338 | #define RCU_GP_IDLE 0 /* No grace period in progress. */ |
339 | #define RCU_GP_INIT 1 /* Grace period being initialized. */ | |
340 | #define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ | |
ee47eb9f | 341 | #define RCU_FORCE_QS 3 /* Need to force quiescent state. */ |
9f77da9f | 342 | #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK |
9f77da9f PM |
343 | |
344 | #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ | |
007b0924 PM |
345 | |
346 | #ifdef CONFIG_PROVE_RCU | |
347 | #define RCU_STALL_DELAY_DELTA (5 * HZ) | |
348 | #else | |
349 | #define RCU_STALL_DELAY_DELTA 0 | |
350 | #endif | |
007b0924 PM |
351 | #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time */ |
352 | /* to take at least one */ | |
353 | /* scheduling clock irq */ | |
354 | /* before ratting on them. */ | |
9f77da9f | 355 | |
08bca60a PZ |
356 | #define rcu_wait(cond) \ |
357 | do { \ | |
358 | for (;;) { \ | |
359 | set_current_state(TASK_INTERRUPTIBLE); \ | |
360 | if (cond) \ | |
361 | break; \ | |
362 | schedule(); \ | |
363 | } \ | |
364 | __set_current_state(TASK_RUNNING); \ | |
365 | } while (0) | |
9f77da9f PM |
366 | |
367 | /* | |
368 | * RCU global state, including node hierarchy. This hierarchy is | |
369 | * represented in "heap" form in a dense array. The root (first level) | |
370 | * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second | |
371 | * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), | |
372 | * and the third level in ->node[m+1] and following (->node[m+1] referenced | |
373 | * by ->level[2]). The number of levels is determined by the number of | |
374 | * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" | |
375 | * consisting of a single rcu_node. | |
376 | */ | |
377 | struct rcu_state { | |
378 | struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ | |
f885b7f2 | 379 | struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */ |
9f77da9f | 380 | u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */ |
f885b7f2 | 381 | u8 levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */ |
394f99a9 | 382 | struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ |
037b64ed PM |
383 | void (*call)(struct rcu_head *head, /* call_rcu() flavor. */ |
384 | void (*func)(struct rcu_head *head)); | |
3fbfbf7a PM |
385 | #ifdef CONFIG_RCU_NOCB_CPU |
386 | void (*call_remote)(struct rcu_head *head, | |
387 | void (*func)(struct rcu_head *head)); | |
388 | /* call_rcu() flavor, but for */ | |
389 | /* placing on remote CPU. */ | |
390 | #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ | |
9f77da9f PM |
391 | |
392 | /* The following fields are guarded by the root rcu_node's lock. */ | |
393 | ||
af446b70 | 394 | u8 fqs_state ____cacheline_internodealigned_in_smp; |
9f77da9f | 395 | /* Force QS state. */ |
a46e0899 | 396 | u8 boost; /* Subject to priority boost. */ |
20133cfc PM |
397 | unsigned long gpnum; /* Current gp number. */ |
398 | unsigned long completed; /* # of last completed gp. */ | |
b3dbec76 PM |
399 | struct task_struct *gp_kthread; /* Task for grace periods. */ |
400 | wait_queue_head_t gp_wq; /* Where GP task waits. */ | |
401 | int gp_flags; /* Commands for GP task. */ | |
1eba8f84 | 402 | |
d9a3da06 | 403 | /* End of fields guarded by root rcu_node's lock. */ |
1eba8f84 | 404 | |
7b2e6011 PM |
405 | raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp; |
406 | /* Protect following fields. */ | |
b1420f1c PM |
407 | struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */ |
408 | /* need a grace period. */ | |
409 | struct rcu_head **orphan_nxttail; /* Tail of above. */ | |
410 | struct rcu_head *orphan_donelist; /* Orphaned callbacks that */ | |
411 | /* are ready to invoke. */ | |
412 | struct rcu_head **orphan_donetail; /* Tail of above. */ | |
413 | long qlen_lazy; /* Number of lazy callbacks. */ | |
414 | long qlen; /* Total number of callbacks. */ | |
7b2e6011 | 415 | /* End of fields guarded by orphan_lock. */ |
a4fbe35a PM |
416 | |
417 | struct mutex onoff_mutex; /* Coordinate hotplug & GPs. */ | |
418 | ||
7be7f0be | 419 | struct mutex barrier_mutex; /* Guards barrier fields. */ |
24ebbca8 | 420 | atomic_t barrier_cpu_count; /* # CPUs waiting on. */ |
7db74df8 | 421 | struct completion barrier_completion; /* Wake at barrier end. */ |
cf3a9c48 PM |
422 | unsigned long n_barrier_done; /* ++ at start and end of */ |
423 | /* _rcu_barrier(). */ | |
a4fbe35a PM |
424 | /* End of fields guarded by barrier_mutex. */ |
425 | ||
40694d66 PM |
426 | atomic_long_t expedited_start; /* Starting ticket. */ |
427 | atomic_long_t expedited_done; /* Done ticket. */ | |
a30489c5 PM |
428 | atomic_long_t expedited_wrap; /* # near-wrap incidents. */ |
429 | atomic_long_t expedited_tryfail; /* # acquisition failures. */ | |
430 | atomic_long_t expedited_workdone1; /* # done by others #1. */ | |
431 | atomic_long_t expedited_workdone2; /* # done by others #2. */ | |
432 | atomic_long_t expedited_normal; /* # fallbacks to normal. */ | |
433 | atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */ | |
434 | atomic_long_t expedited_done_tries; /* # tries to update _done. */ | |
435 | atomic_long_t expedited_done_lost; /* # times beaten to _done. */ | |
436 | atomic_long_t expedited_done_exit; /* # times exited _done loop. */ | |
40694d66 | 437 | |
9f77da9f PM |
438 | unsigned long jiffies_force_qs; /* Time at which to invoke */ |
439 | /* force_quiescent_state(). */ | |
440 | unsigned long n_force_qs; /* Number of calls to */ | |
441 | /* force_quiescent_state(). */ | |
442 | unsigned long n_force_qs_lh; /* ~Number of calls leaving */ | |
443 | /* due to lock unavailable. */ | |
444 | unsigned long n_force_qs_ngp; /* Number of calls leaving */ | |
445 | /* due to no GP active. */ | |
9f77da9f PM |
446 | unsigned long gp_start; /* Time at which GP started, */ |
447 | /* but in jiffies. */ | |
448 | unsigned long jiffies_stall; /* Time at which to check */ | |
449 | /* for CPU stalls. */ | |
15ba0ba8 PM |
450 | unsigned long gp_max; /* Maximum GP duration in */ |
451 | /* jiffies. */ | |
4300aa64 | 452 | char *name; /* Name of structure. */ |
6ce75a23 | 453 | struct list_head flavors; /* List of RCU flavors. */ |
9f77da9f PM |
454 | }; |
455 | ||
4cdfc175 PM |
456 | /* Values for rcu_state structure's gp_flags field. */ |
457 | #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ | |
458 | #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ | |
459 | ||
6ce75a23 | 460 | extern struct list_head rcu_struct_flavors; |
3fbfbf7a PM |
461 | |
462 | /* Sequence through rcu_state structures for each RCU flavor. */ | |
6ce75a23 PM |
463 | #define for_each_rcu_flavor(rsp) \ |
464 | list_for_each_entry((rsp), &rcu_struct_flavors, flavors) | |
465 | ||
d9a3da06 PM |
466 | /* Return values for rcu_preempt_offline_tasks(). */ |
467 | ||
468 | #define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */ | |
469 | /* GP were moved to root. */ | |
470 | #define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */ | |
471 | /* GP were moved to root. */ | |
472 | ||
6258c4fb IM |
473 | /* |
474 | * RCU implementation internal declarations: | |
475 | */ | |
d6714c22 PM |
476 | extern struct rcu_state rcu_sched_state; |
477 | DECLARE_PER_CPU(struct rcu_data, rcu_sched_data); | |
6258c4fb IM |
478 | |
479 | extern struct rcu_state rcu_bh_state; | |
480 | DECLARE_PER_CPU(struct rcu_data, rcu_bh_data); | |
481 | ||
f41d911f PM |
482 | #ifdef CONFIG_TREE_PREEMPT_RCU |
483 | extern struct rcu_state rcu_preempt_state; | |
484 | DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); | |
485 | #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ | |
486 | ||
eab0993c PM |
487 | #ifdef CONFIG_RCU_BOOST |
488 | DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); | |
489 | DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); | |
490 | DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); | |
491 | DECLARE_PER_CPU(char, rcu_cpu_has_work); | |
492 | #endif /* #ifdef CONFIG_RCU_BOOST */ | |
493 | ||
017c4261 | 494 | #ifndef RCU_TREE_NONCORE |
9f77da9f | 495 | |
9b2619af | 496 | /* Forward declarations for rcutree_plugin.h */ |
dbe01350 | 497 | static void rcu_bootup_announce(void); |
9b2619af | 498 | long rcu_batches_completed(void); |
cba6d0d6 | 499 | static void rcu_preempt_note_context_switch(int cpu); |
27f4d280 | 500 | static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); |
b668c9cf | 501 | #ifdef CONFIG_HOTPLUG_CPU |
d3f6bad3 PM |
502 | static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, |
503 | unsigned long flags); | |
b668c9cf | 504 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
1ed509a2 | 505 | static void rcu_print_detail_task_stall(struct rcu_state *rsp); |
9bc8b558 | 506 | static int rcu_print_task_stall(struct rcu_node *rnp); |
9b2619af PM |
507 | static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); |
508 | #ifdef CONFIG_HOTPLUG_CPU | |
237c80c5 PM |
509 | static int rcu_preempt_offline_tasks(struct rcu_state *rsp, |
510 | struct rcu_node *rnp, | |
511 | struct rcu_data *rdp); | |
9b2619af PM |
512 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
513 | static void rcu_preempt_check_callbacks(int cpu); | |
9b2619af | 514 | void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); |
d9a3da06 | 515 | #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) |
b40d293e TG |
516 | static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, |
517 | bool wake); | |
d9a3da06 | 518 | #endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */ |
9b2619af | 519 | static void __init __rcu_init_preempt(void); |
1217ed1b | 520 | static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); |
a46e0899 PM |
521 | static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); |
522 | static void invoke_rcu_callbacks_kthread(void); | |
dff1672d | 523 | static bool rcu_is_callbacks_kthread(void); |
a46e0899 PM |
524 | #ifdef CONFIG_RCU_BOOST |
525 | static void rcu_preempt_do_callbacks(void); | |
27f4d280 | 526 | static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, |
5d01bbd1 | 527 | struct rcu_node *rnp); |
a46e0899 | 528 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
f8b7fc6b | 529 | static void __cpuinit rcu_prepare_kthreads(int cpu); |
7cb92499 PM |
530 | static void rcu_prepare_for_idle_init(int cpu); |
531 | static void rcu_cleanup_after_idle(int cpu); | |
aea1b35e | 532 | static void rcu_prepare_for_idle(int cpu); |
c57afe80 | 533 | static void rcu_idle_count_callbacks_posted(void); |
a858af28 PM |
534 | static void print_cpu_stall_info_begin(void); |
535 | static void print_cpu_stall_info(struct rcu_state *rsp, int cpu); | |
536 | static void print_cpu_stall_info_end(void); | |
537 | static void zero_cpu_stall_ticks(struct rcu_data *rdp); | |
538 | static void increment_cpu_stall_ticks(void); | |
3fbfbf7a PM |
539 | static bool is_nocb_cpu(int cpu); |
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 bool nocb_cpu_expendable(int cpu); | |
545 | static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); | |
546 | static void rcu_spawn_nocb_kthreads(struct rcu_state *rsp); | |
547 | static void init_nocb_callback_list(struct rcu_data *rdp); | |
548 | static void __init rcu_init_nocb(void); | |
9b2619af | 549 | |
017c4261 | 550 | #endif /* #ifndef RCU_TREE_NONCORE */ |
3fbfbf7a PM |
551 | |
552 | #ifdef CONFIG_RCU_TRACE | |
553 | #ifdef CONFIG_RCU_NOCB_CPU | |
554 | /* Sum up queue lengths for tracing. */ | |
555 | static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) | |
556 | { | |
557 | *ql = atomic_long_read(&rdp->nocb_q_count) + rdp->nocb_p_count; | |
558 | *qll = atomic_long_read(&rdp->nocb_q_count_lazy) + rdp->nocb_p_count_lazy; | |
559 | } | |
560 | #else /* #ifdef CONFIG_RCU_NOCB_CPU */ | |
561 | static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) | |
562 | { | |
563 | *ql = 0; | |
564 | *qll = 0; | |
565 | } | |
566 | #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ | |
567 | #endif /* #ifdef CONFIG_RCU_TRACE */ |