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Paul E. McKenney9f77da92009-08-22 13:56:45 -07001/*
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/*
32 * Define shape of hierarchy based on NR_CPUS and CONFIG_RCU_FANOUT.
33 * In theory, it should be possible to add more levels straightforwardly.
Paul E. McKenney0209f642010-12-14 16:07:52 -080034 * In practice, this did work well going from three levels to four.
35 * Of course, your mileage may vary.
Paul E. McKenney9f77da92009-08-22 13:56:45 -070036 */
Paul E. McKenneycf244dc2009-12-02 12:10:14 -080037#define MAX_RCU_LVLS 4
Paul E. McKenney0209f642010-12-14 16:07:52 -080038#if CONFIG_RCU_FANOUT > 16
39#define RCU_FANOUT_LEAF 16
40#else /* #if CONFIG_RCU_FANOUT > 16 */
41#define RCU_FANOUT_LEAF (CONFIG_RCU_FANOUT)
42#endif /* #else #if CONFIG_RCU_FANOUT > 16 */
43#define RCU_FANOUT_1 (RCU_FANOUT_LEAF)
44#define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT)
45#define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT)
46#define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT)
Paul E. McKenney9f77da92009-08-22 13:56:45 -070047
Paul E. McKenney0209f642010-12-14 16:07:52 -080048#if NR_CPUS <= RCU_FANOUT_1
Paul E. McKenney9f77da92009-08-22 13:56:45 -070049# define NUM_RCU_LVLS 1
50# define NUM_RCU_LVL_0 1
51# define NUM_RCU_LVL_1 (NR_CPUS)
52# define NUM_RCU_LVL_2 0
53# define NUM_RCU_LVL_3 0
Paul E. McKenneycf244dc2009-12-02 12:10:14 -080054# define NUM_RCU_LVL_4 0
Paul E. McKenney0209f642010-12-14 16:07:52 -080055#elif NR_CPUS <= RCU_FANOUT_2
Paul E. McKenney9f77da92009-08-22 13:56:45 -070056# define NUM_RCU_LVLS 2
57# define NUM_RCU_LVL_0 1
Paul E. McKenney0209f642010-12-14 16:07:52 -080058# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
Paul E. McKenney9f77da92009-08-22 13:56:45 -070059# define NUM_RCU_LVL_2 (NR_CPUS)
60# define NUM_RCU_LVL_3 0
Paul E. McKenneycf244dc2009-12-02 12:10:14 -080061# define NUM_RCU_LVL_4 0
Paul E. McKenney0209f642010-12-14 16:07:52 -080062#elif NR_CPUS <= RCU_FANOUT_3
Paul E. McKenney9f77da92009-08-22 13:56:45 -070063# define NUM_RCU_LVLS 3
64# define NUM_RCU_LVL_0 1
Paul E. McKenney0209f642010-12-14 16:07:52 -080065# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
66# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
67# define NUM_RCU_LVL_3 (NR_CPUS)
Paul E. McKenneycf244dc2009-12-02 12:10:14 -080068# define NUM_RCU_LVL_4 0
Paul E. McKenney0209f642010-12-14 16:07:52 -080069#elif NR_CPUS <= RCU_FANOUT_4
Paul E. McKenneycf244dc2009-12-02 12:10:14 -080070# define NUM_RCU_LVLS 4
71# define NUM_RCU_LVL_0 1
Paul E. McKenney0209f642010-12-14 16:07:52 -080072# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
73# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
74# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
75# define NUM_RCU_LVL_4 (NR_CPUS)
Paul E. McKenney9f77da92009-08-22 13:56:45 -070076#else
77# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
Paul E. McKenney0209f642010-12-14 16:07:52 -080078#endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */
Paul E. McKenney9f77da92009-08-22 13:56:45 -070079
Paul E. McKenneycf244dc2009-12-02 12:10:14 -080080#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4)
Paul E. McKenney9f77da92009-08-22 13:56:45 -070081#define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
82
83/*
84 * Dynticks per-CPU state.
85 */
86struct rcu_dynticks {
Paul E. McKenney80d02082011-05-12 01:08:07 -070087 int dynticks_nesting; /* Track nesting level, sort of. */
88 int dynticks; /* Even value for dynticks-idle, else odd. */
89 int dynticks_nmi; /* Even value for either dynticks-idle or */
90 /* not in nmi handler, else odd. So this */
91 /* remains even for nmi from irq handler. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -070092};
93
Paul E. McKenneyd71df902011-03-29 17:48:28 -070094/* RCU's kthread states for tracing. */
95#define RCU_KTHREAD_STOPPED 0
96#define RCU_KTHREAD_RUNNING 1
97#define RCU_KTHREAD_WAITING 2
Paul E. McKenney15ba0ba2011-04-06 16:01:16 -070098#define RCU_KTHREAD_OFFCPU 3
99#define RCU_KTHREAD_YIELDING 4
100#define RCU_KTHREAD_MAX 4
Paul E. McKenneyd71df902011-03-29 17:48:28 -0700101
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700102/*
103 * Definition for node within the RCU grace-period-detection hierarchy.
104 */
105struct rcu_node {
Paul E. McKenney1304afb2010-02-22 17:05:02 -0800106 raw_spinlock_t lock; /* Root rcu_node's lock protects some */
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700107 /* rcu_state fields as well as following. */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800108 unsigned long gpnum; /* Current grace period for this node. */
Paul E. McKenney86848962009-08-27 15:00:12 -0700109 /* This will either be equal to or one */
110 /* behind the root rcu_node's gpnum. */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800111 unsigned long completed; /* Last GP completed for this node. */
Paul E. McKenneyd09b62d2009-11-02 13:52:28 -0800112 /* This will either be equal to or one */
113 /* behind the root rcu_node's gpnum. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700114 unsigned long qsmask; /* CPUs or groups that need to switch in */
115 /* order for current grace period to proceed.*/
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700116 /* In leaf rcu_node, each bit corresponds to */
117 /* an rcu_data structure, otherwise, each */
118 /* bit corresponds to a child rcu_node */
119 /* structure. */
Paul E. McKenney12f5f522010-11-29 21:56:39 -0800120 unsigned long expmask; /* Groups that have ->blkd_tasks */
Paul E. McKenneyd9a3da02009-12-02 12:10:15 -0800121 /* elements that need to drain to allow the */
122 /* current expedited grace period to */
123 /* complete (only for TREE_PREEMPT_RCU). */
Paul E. McKenneya26ac242011-01-12 14:10:23 -0800124 unsigned long wakemask; /* CPUs whose kthread needs to be awakened. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700125 unsigned long qsmaskinit;
Paul E. McKenneyd9a3da02009-12-02 12:10:15 -0800126 /* Per-GP initial value for qsmask & expmask. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700127 unsigned long grpmask; /* Mask to apply to parent qsmask. */
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700128 /* Only one bit will be set in this mask. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700129 int grplo; /* lowest-numbered CPU or group here. */
130 int grphi; /* highest-numbered CPU or group here. */
131 u8 grpnum; /* CPU/group number for next level up. */
132 u8 level; /* root is at level 0. */
133 struct rcu_node *parent;
Paul E. McKenney12f5f522010-11-29 21:56:39 -0800134 struct list_head blkd_tasks;
135 /* Tasks blocked in RCU read-side critical */
136 /* section. Tasks are placed at the head */
137 /* of this list and age towards the tail. */
138 struct list_head *gp_tasks;
139 /* Pointer to the first task blocking the */
140 /* current grace period, or NULL if there */
141 /* is no such task. */
142 struct list_head *exp_tasks;
143 /* Pointer to the first task blocking the */
144 /* current expedited grace period, or NULL */
145 /* if there is no such task. If there */
146 /* is no current expedited grace period, */
147 /* then there can cannot be any such task. */
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800148#ifdef CONFIG_RCU_BOOST
149 struct list_head *boost_tasks;
150 /* Pointer to first task that needs to be */
151 /* priority boosted, or NULL if no priority */
152 /* boosting is needed for this rcu_node */
153 /* structure. If there are no tasks */
154 /* queued on this rcu_node structure that */
155 /* are blocking the current grace period, */
156 /* there can be no such task. */
157 unsigned long boost_time;
158 /* When to start boosting (jiffies). */
159 struct task_struct *boost_kthread_task;
160 /* kthread that takes care of priority */
161 /* boosting for this rcu_node structure. */
162 wait_queue_head_t boost_wq;
163 /* Wait queue on which to park the boost */
164 /* kthread. */
Paul E. McKenneyd71df902011-03-29 17:48:28 -0700165 unsigned int boost_kthread_status;
166 /* State of boost_kthread_task for tracing. */
Paul E. McKenney0ea1f2e2011-02-22 13:42:43 -0800167 unsigned long n_tasks_boosted;
168 /* Total number of tasks boosted. */
169 unsigned long n_exp_boosts;
170 /* Number of tasks boosted for expedited GP. */
171 unsigned long n_normal_boosts;
172 /* Number of tasks boosted for normal GP. */
173 unsigned long n_balk_blkd_tasks;
174 /* Refused to boost: no blocked tasks. */
175 unsigned long n_balk_exp_gp_tasks;
176 /* Refused to boost: nothing blocking GP. */
177 unsigned long n_balk_boost_tasks;
178 /* Refused to boost: already boosting. */
179 unsigned long n_balk_notblocked;
180 /* Refused to boost: RCU RS CS still running. */
181 unsigned long n_balk_notyet;
182 /* Refused to boost: not yet time. */
183 unsigned long n_balk_nos;
184 /* Refused to boost: not sure why, though. */
185 /* This can happen due to race conditions. */
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800186#endif /* #ifdef CONFIG_RCU_BOOST */
Paul E. McKenneya26ac242011-01-12 14:10:23 -0800187 struct task_struct *node_kthread_task;
188 /* kthread that takes care of this rcu_node */
189 /* structure, for example, awakening the */
190 /* per-CPU kthreads as needed. */
191 wait_queue_head_t node_wq;
192 /* Wait queue on which to park the per-node */
193 /* kthread. */
Paul E. McKenneyd71df902011-03-29 17:48:28 -0700194 unsigned int node_kthread_status;
195 /* State of node_kthread_task for tracing. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700196} ____cacheline_internodealigned_in_smp;
197
Paul E. McKenneya0b6c9a2009-09-28 07:46:33 -0700198/*
199 * Do a full breadth-first scan of the rcu_node structures for the
200 * specified rcu_state structure.
201 */
202#define rcu_for_each_node_breadth_first(rsp, rnp) \
203 for ((rnp) = &(rsp)->node[0]; \
204 (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
205
Paul E. McKenneyd9a3da02009-12-02 12:10:15 -0800206/*
207 * Do a breadth-first scan of the non-leaf rcu_node structures for the
208 * specified rcu_state structure. Note that if there is a singleton
209 * rcu_node tree with but one rcu_node structure, this loop is a no-op.
210 */
211#define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
212 for ((rnp) = &(rsp)->node[0]; \
213 (rnp) < (rsp)->level[NUM_RCU_LVLS - 1]; (rnp)++)
214
215/*
216 * Scan the leaves of the rcu_node hierarchy for the specified rcu_state
217 * structure. Note that if there is a singleton rcu_node tree with but
218 * one rcu_node structure, this loop -will- visit the rcu_node structure.
219 * It is still a leaf node, even if it is also the root node.
220 */
Paul E. McKenneya0b6c9a2009-09-28 07:46:33 -0700221#define rcu_for_each_leaf_node(rsp, rnp) \
222 for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \
223 (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
224
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700225/* Index values for nxttail array in struct rcu_data. */
226#define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */
227#define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */
228#define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */
229#define RCU_NEXT_TAIL 3
230#define RCU_NEXT_SIZE 4
231
232/* Per-CPU data for read-copy update. */
233struct rcu_data {
234 /* 1) quiescent-state and grace-period handling : */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800235 unsigned long completed; /* Track rsp->completed gp number */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700236 /* in order to detect GP end. */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800237 unsigned long gpnum; /* Highest gp number that this CPU */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700238 /* is aware of having started. */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800239 unsigned long passed_quiesc_completed;
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700240 /* Value of completed at time of qs. */
241 bool passed_quiesc; /* User-mode/idle loop etc. */
242 bool qs_pending; /* Core waits for quiesc state. */
243 bool beenonline; /* CPU online at least once. */
Paul E. McKenney6cc68792011-03-02 13:15:15 -0800244 bool preemptible; /* Preemptible RCU? */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700245 struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
246 unsigned long grpmask; /* Mask to apply to leaf qsmask. */
247
248 /* 2) batch handling */
249 /*
250 * If nxtlist is not NULL, it is partitioned as follows.
251 * Any of the partitions might be empty, in which case the
252 * pointer to that partition will be equal to the pointer for
253 * the following partition. When the list is empty, all of
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700254 * the nxttail elements point to the ->nxtlist pointer itself,
255 * which in that case is NULL.
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700256 *
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700257 * [nxtlist, *nxttail[RCU_DONE_TAIL]):
258 * Entries that batch # <= ->completed
259 * The grace period for these entries has completed, and
260 * the other grace-period-completed entries may be moved
261 * here temporarily in rcu_process_callbacks().
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700262 * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
263 * Entries that batch # <= ->completed - 1: waiting for current GP
264 * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
265 * Entries known to have arrived before current GP ended
266 * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]):
267 * Entries that might have arrived after current GP ended
268 * Note that the value of *nxttail[RCU_NEXT_TAIL] will
269 * always be NULL, as this is the end of the list.
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700270 */
271 struct rcu_head *nxtlist;
272 struct rcu_head **nxttail[RCU_NEXT_SIZE];
Paul E. McKenneya71fca52009-09-18 10:28:19 -0700273 long qlen; /* # of queued callbacks */
Paul E. McKenney37c72e52009-10-14 10:15:55 -0700274 long qlen_last_fqs_check;
275 /* qlen at last check for QS forcing */
Paul E. McKenney269dcc12010-09-07 14:23:09 -0700276 unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */
Lai Jiangshan29494be2010-10-20 14:13:06 +0800277 unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */
278 unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */
Paul E. McKenney37c72e52009-10-14 10:15:55 -0700279 unsigned long n_force_qs_snap;
280 /* did other CPU force QS recently? */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700281 long blimit; /* Upper limit on a processed batch */
282
283#ifdef CONFIG_NO_HZ
284 /* 3) dynticks interface. */
285 struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */
286 int dynticks_snap; /* Per-GP tracking for dynticks. */
Paul E. McKenney80d02082011-05-12 01:08:07 -0700287 int dynticks_nmi_snap; /* Per-GP tracking for dynticks_nmi. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700288#endif /* #ifdef CONFIG_NO_HZ */
289
290 /* 4) reasons this CPU needed to be kicked by force_quiescent_state */
291#ifdef CONFIG_NO_HZ
292 unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */
293#endif /* #ifdef CONFIG_NO_HZ */
294 unsigned long offline_fqs; /* Kicked due to being offline. */
295 unsigned long resched_ipi; /* Sent a resched IPI. */
296
297 /* 5) __rcu_pending() statistics. */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800298 unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */
299 unsigned long n_rp_qs_pending;
Paul E. McKenneyd21670a2010-04-14 17:39:26 -0700300 unsigned long n_rp_report_qs;
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800301 unsigned long n_rp_cb_ready;
302 unsigned long n_rp_cpu_needs_gp;
303 unsigned long n_rp_gp_completed;
304 unsigned long n_rp_gp_started;
305 unsigned long n_rp_need_fqs;
306 unsigned long n_rp_need_nothing;
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700307
308 int cpu;
309};
310
311/* Values for signaled field in struct rcu_state. */
Paul E. McKenney83f5b012009-10-28 08:14:49 -0700312#define RCU_GP_IDLE 0 /* No grace period in progress. */
313#define RCU_GP_INIT 1 /* Grace period being initialized. */
314#define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */
Paul E. McKenneyee47eb92010-01-04 15:09:07 -0800315#define RCU_FORCE_QS 3 /* Need to force quiescent state. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700316#ifdef CONFIG_NO_HZ
317#define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK
318#else /* #ifdef CONFIG_NO_HZ */
Paul E. McKenneyee47eb92010-01-04 15:09:07 -0800319#define RCU_SIGNAL_INIT RCU_FORCE_QS
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700320#endif /* #else #ifdef CONFIG_NO_HZ */
321
322#define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */
Paul E. McKenney007b0922010-03-05 15:03:26 -0800323
324#ifdef CONFIG_PROVE_RCU
325#define RCU_STALL_DELAY_DELTA (5 * HZ)
326#else
327#define RCU_STALL_DELAY_DELTA 0
328#endif
329
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700330#define RCU_SECONDS_TILL_STALL_CHECK (CONFIG_RCU_CPU_STALL_TIMEOUT * HZ + \
331 RCU_STALL_DELAY_DELTA)
Paul E. McKenney007b0922010-03-05 15:03:26 -0800332 /* for rsp->jiffies_stall */
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700333#define RCU_SECONDS_TILL_STALL_RECHECK (3 * RCU_SECONDS_TILL_STALL_CHECK + 30)
Paul E. McKenney007b0922010-03-05 15:03:26 -0800334 /* for rsp->jiffies_stall */
335#define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time */
336 /* to take at least one */
337 /* scheduling clock irq */
338 /* before ratting on them. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700339
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700340
341/*
342 * RCU global state, including node hierarchy. This hierarchy is
343 * represented in "heap" form in a dense array. The root (first level)
344 * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
345 * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
346 * and the third level in ->node[m+1] and following (->node[m+1] referenced
347 * by ->level[2]). The number of levels is determined by the number of
348 * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy"
349 * consisting of a single rcu_node.
350 */
351struct rcu_state {
352 struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
353 struct rcu_node *level[NUM_RCU_LVLS]; /* Hierarchy levels. */
354 u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */
355 u8 levelspread[NUM_RCU_LVLS]; /* kids/node in each level. */
Lai Jiangshan394f99a2010-06-28 16:25:04 +0800356 struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700357
358 /* The following fields are guarded by the root rcu_node's lock. */
359
360 u8 signaled ____cacheline_internodealigned_in_smp;
361 /* Force QS state. */
Paul E. McKenney07079d52010-01-04 15:09:02 -0800362 u8 fqs_active; /* force_quiescent_state() */
363 /* is running. */
Paul E. McKenney46a1e342010-01-04 15:09:09 -0800364 u8 fqs_need_gp; /* A CPU was prevented from */
365 /* starting a new grace */
366 /* period because */
367 /* force_quiescent_state() */
368 /* was running. */
Paul E. McKenney20133cf2010-02-22 17:05:01 -0800369 unsigned long gpnum; /* Current gp number. */
370 unsigned long completed; /* # of last completed gp. */
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700371
Paul E. McKenneyd9a3da02009-12-02 12:10:15 -0800372 /* End of fields guarded by root rcu_node's lock. */
Paul E. McKenney1eba8f82009-09-23 09:50:42 -0700373
Paul E. McKenney1304afb2010-02-22 17:05:02 -0800374 raw_spinlock_t onofflock; /* exclude on/offline and */
Lai Jiangshan29494be2010-10-20 14:13:06 +0800375 /* starting new GP. */
Paul E. McKenney1304afb2010-02-22 17:05:02 -0800376 raw_spinlock_t fqslock; /* Only one task forcing */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700377 /* quiescent states. */
378 unsigned long jiffies_force_qs; /* Time at which to invoke */
379 /* force_quiescent_state(). */
380 unsigned long n_force_qs; /* Number of calls to */
381 /* force_quiescent_state(). */
382 unsigned long n_force_qs_lh; /* ~Number of calls leaving */
383 /* due to lock unavailable. */
384 unsigned long n_force_qs_ngp; /* Number of calls leaving */
385 /* due to no GP active. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700386 unsigned long gp_start; /* Time at which GP started, */
387 /* but in jiffies. */
388 unsigned long jiffies_stall; /* Time at which to check */
389 /* for CPU stalls. */
Paul E. McKenney15ba0ba2011-04-06 16:01:16 -0700390 unsigned long gp_max; /* Maximum GP duration in */
391 /* jiffies. */
Paul E. McKenney4300aa62010-04-13 16:18:22 -0700392 char *name; /* Name of structure. */
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700393};
394
Paul E. McKenneyd9a3da02009-12-02 12:10:15 -0800395/* Return values for rcu_preempt_offline_tasks(). */
396
397#define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */
398 /* GP were moved to root. */
399#define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */
400 /* GP were moved to root. */
401
Ingo Molnar6258c4f2009-03-25 16:42:24 +0100402/*
403 * RCU implementation internal declarations:
404 */
Paul E. McKenneyd6714c22009-08-22 13:56:46 -0700405extern struct rcu_state rcu_sched_state;
406DECLARE_PER_CPU(struct rcu_data, rcu_sched_data);
Ingo Molnar6258c4f2009-03-25 16:42:24 +0100407
408extern struct rcu_state rcu_bh_state;
409DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
410
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700411#ifdef CONFIG_TREE_PREEMPT_RCU
412extern struct rcu_state rcu_preempt_state;
413DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
414#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
415
Paul E. McKenney017c4262010-01-14 16:10:58 -0800416#ifndef RCU_TREE_NONCORE
Paul E. McKenney9f77da92009-08-22 13:56:45 -0700417
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700418/* Forward declarations for rcutree_plugin.h */
Paul E. McKenneydbe01352009-11-10 13:37:19 -0800419static void rcu_bootup_announce(void);
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700420long rcu_batches_completed(void);
421static void rcu_preempt_note_context_switch(int cpu);
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800422static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
Paul E. McKenneyb668c9c2009-11-22 08:53:48 -0800423#ifdef CONFIG_HOTPLUG_CPU
Paul E. McKenneyd3f6bad2009-12-02 12:10:13 -0800424static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
425 unsigned long flags);
Paul E. McKenneyb668c9c2009-11-22 08:53:48 -0800426#endif /* #ifdef CONFIG_HOTPLUG_CPU */
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800427static void rcu_print_detail_task_stall(struct rcu_state *rsp);
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700428static void rcu_print_task_stall(struct rcu_node *rnp);
Paul E. McKenney53d84e02010-08-10 14:28:53 -0700429static void rcu_preempt_stall_reset(void);
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700430static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
431#ifdef CONFIG_HOTPLUG_CPU
Paul E. McKenney237c80c2009-10-15 09:26:14 -0700432static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
433 struct rcu_node *rnp,
434 struct rcu_data *rdp);
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700435static void rcu_preempt_offline_cpu(int cpu);
436#endif /* #ifdef CONFIG_HOTPLUG_CPU */
437static void rcu_preempt_check_callbacks(int cpu);
438static void rcu_preempt_process_callbacks(void);
439void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
Paul E. McKenneyd9a3da02009-12-02 12:10:15 -0800440#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU)
441static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp);
442#endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700443static int rcu_preempt_pending(int cpu);
444static int rcu_preempt_needs_cpu(int cpu);
445static void __cpuinit rcu_preempt_init_percpu_data(int cpu);
Lai Jiangshan29494be2010-10-20 14:13:06 +0800446static void rcu_preempt_send_cbs_to_online(void);
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700447static void __init __rcu_init_preempt(void);
Paul E. McKenneya47cd882010-02-26 16:38:56 -0800448static void rcu_needs_cpu_flush(void);
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800449static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp);
Paul E. McKenney1217ed12011-05-04 21:43:49 -0700450static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800451static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp,
452 cpumask_var_t cm);
453static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
454static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
455 struct rcu_node *rnp,
456 int rnp_index);
Paul E. McKenney9b2619a2009-09-23 09:50:43 -0700457
Paul E. McKenney017c4262010-01-14 16:10:58 -0800458#endif /* #ifndef RCU_TREE_NONCORE */