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2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376 
 kernel/kernel/rcu/tree.h
....@@ -1,25 +1,12 @@
1
+/* SPDX-License-Identifier: GPL-2.0+ */
12 /*
23  * Read-Copy Update mechanism for mutual exclusion (tree-based version)
34  * Internal non-public definitions.
45  *
5
- * This program is free software; you can redistribute it and/or modify
6
- * it under the terms of the GNU General Public License as published by
7
- * the Free Software Foundation; either version 2 of the License, or
8
- * (at your option) any later version.
9
- *
10
- * This program is distributed in the hope that it will be useful,
11
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
12
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13
- * GNU General Public License for more details.
14
- *
15
- * You should have received a copy of the GNU General Public License
16
- * along with this program; if not, you can access it online at
17
- * http://www.gnu.org/licenses/gpl-2.0.html.
18
- *
196  * Copyright IBM Corporation, 2008
207  *
218  * Author: Ingo Molnar <mingo@elte.hu>
22
- *	   Paul E. McKenney <paulmck@linux.vnet.ibm.com>
9
+ *	   Paul E. McKenney <paulmck@linux.ibm.com>
2310  */
2411 
2512 #include <linux/cache.h>
....@@ -29,39 +16,12 @@
2916 #include <linux/cpumask.h>
3017 #include <linux/seqlock.h>
3118 #include <linux/swait.h>
32
-#include <linux/stop_machine.h>
3319 #include <linux/rcu_node_tree.h>
3420 
3521 #include "rcu_segcblist.h"
3622 
37
-/*
38
- * Dynticks per-CPU state.
39
- */
40
-struct rcu_dynticks {
41
-	long dynticks_nesting;      /* Track process nesting level. */
42
-	long dynticks_nmi_nesting;  /* Track irq/NMI nesting level. */
43
-	atomic_t dynticks;	    /* Even value for idle, else odd. */
44
-	bool rcu_need_heavy_qs;     /* GP old, need heavy quiescent state. */
45
-	unsigned long rcu_qs_ctr;   /* Light universal quiescent state ctr. */
46
-	bool rcu_urgent_qs;	    /* GP old need light quiescent state. */
47
-#ifdef CONFIG_RCU_FAST_NO_HZ
48
-	bool all_lazy;		    /* Are all CPU's CBs lazy? */
49
-	unsigned long nonlazy_posted;
50
-				    /* # times non-lazy CBs posted to CPU. */
51
-	unsigned long nonlazy_posted_snap;
52
-				    /* idle-period nonlazy_posted snapshot. */
53
-	unsigned long last_accelerate;
54
-				    /* Last jiffy CBs were accelerated. */
55
-	unsigned long last_advance_all;
56
-				    /* Last jiffy CBs were all advanced. */
57
-	int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
58
-#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
59
-};
60
-
6123 /* Communicate arguments to a workqueue handler. */
6224 struct rcu_exp_work {
63
-	smp_call_func_t rew_func;
64
-	struct rcu_state *rew_rsp;
6525 	unsigned long rew_s;
6626 	struct work_struct rew_work;
6727 };
....@@ -81,8 +41,8 @@
8141 	raw_spinlock_t __private lock;	/* Root rcu_node's lock protects */
8242 					/*  some rcu_state fields as well as */
8343 					/*  following. */
84
-	unsigned long gp_seq;	/* Track rsp->rcu_gp_seq. */
85
-	unsigned long gp_seq_needed; /* Track rsp->rcu_gp_seq_needed. */
44
+	unsigned long gp_seq;	/* Track rsp->gp_seq. */
45
+	unsigned long gp_seq_needed; /* Track furthest future GP request. */
8646 	unsigned long completedqs; /* All QSes done for this node. */
8747 	unsigned long qsmask;	/* CPUs or groups that need to switch in */
8848 				/*  order for current grace period to proceed.*/
....@@ -108,12 +68,14 @@
10868 				/* Online CPUs for next expedited GP. */
10969 				/*  Any CPU that has ever been online will */
11070 				/*  have its bit set. */
71
+	unsigned long cbovldmask;
72
+				/* CPUs experiencing callback overload. */
11173 	unsigned long ffmask;	/* Fully functional CPUs. */
11274 	unsigned long grpmask;	/* Mask to apply to parent qsmask. */
11375 				/*  Only one bit will be set in this mask. */
114
-	int	grplo;		/* lowest-numbered CPU or group here. */
115
-	int	grphi;		/* highest-numbered CPU or group here. */
116
-	u8	grpnum;		/* CPU/group number for next level up. */
76
+	int	grplo;		/* lowest-numbered CPU here. */
77
+	int	grphi;		/* highest-numbered CPU here. */
78
+	u8	grpnum;		/* group number for next level up. */
11779 	u8	level;		/* root is at level 0. */
11880 	bool	wait_blkd_tasks;/* Necessary to wait for blocked tasks to */
11981 				/*  exit RCU read-side critical sections */
....@@ -170,7 +132,7 @@
170132  * are indexed relative to this interval rather than the global CPU ID space.
171133  * This generates the bit for a CPU in node-local masks.
172134  */
173
-#define leaf_node_cpu_bit(rnp, cpu) (1UL << ((cpu) - (rnp)->grplo))
135
+#define leaf_node_cpu_bit(rnp, cpu) (BIT((cpu) - (rnp)->grplo))
174136 
175137 /*
176138  * Union to allow "aggregate OR" operation on the need for a quiescent
....@@ -187,20 +149,23 @@
187149 /* Per-CPU data for read-copy update. */
188150 struct rcu_data {
189151 	/* 1) quiescent-state and grace-period handling : */
190
-	unsigned long	gp_seq;		/* Track rsp->rcu_gp_seq counter. */
191
-	unsigned long	gp_seq_needed;	/* Track rsp->rcu_gp_seq_needed ctr. */
192
-	unsigned long	rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
193
-					/*  for rcu_all_qs() invocations. */
152
+	unsigned long	gp_seq;		/* Track rsp->gp_seq counter. */
153
+	unsigned long	gp_seq_needed;	/* Track furthest future GP request. */
194154 	union rcu_noqs	cpu_no_qs;	/* No QSes yet for this CPU. */
195155 	bool		core_needs_qs;	/* Core waits for quiesc state. */
196156 	bool		beenonline;	/* CPU online at least once. */
197157 	bool		gpwrap;		/* Possible ->gp_seq wrap. */
158
+	bool		exp_deferred_qs; /* This CPU awaiting a deferred QS? */
159
+	bool		cpu_started;	/* RCU watching this onlining CPU. */
198160 	struct rcu_node *mynode;	/* This CPU's leaf of hierarchy */
199161 	unsigned long grpmask;		/* Mask to apply to leaf qsmask. */
200162 	unsigned long	ticks_this_gp;	/* The number of scheduling-clock */
201163 					/*  ticks this CPU has handled */
202164 					/*  during and after the last grace */
203165 					/* period it is aware of. */
166
+	struct irq_work defer_qs_iw;	/* Obtain later scheduler attention. */
167
+	bool defer_qs_iw_pending;	/* Scheduler attention pending? */
168
+	struct work_struct strict_work;	/* Schedule readers for strict GPs. */
204169 
205170 	/* 2) batch handling */
206171 	struct rcu_segcblist cblist;	/* Segmented callback list, with */
....@@ -208,53 +173,71 @@
208173 					/* different grace periods. */
209174 	long		qlen_last_fqs_check;
210175 					/* qlen at last check for QS forcing */
176
+	unsigned long	n_cbs_invoked;	/* # callbacks invoked since boot. */
211177 	unsigned long	n_force_qs_snap;
212178 					/* did other CPU force QS recently? */
213179 	long		blimit;		/* Upper limit on a processed batch */
214180 
215181 	/* 3) dynticks interface. */
216
-	struct rcu_dynticks *dynticks;	/* Shared per-CPU dynticks state. */
217182 	int dynticks_snap;		/* Per-GP tracking for dynticks. */
218
-
219
-	/* 4) reasons this CPU needed to be kicked by force_quiescent_state */
220
-	unsigned long dynticks_fqs;	/* Kicked due to dynticks idle. */
221
-	unsigned long cond_resched_completed;
222
-					/* Grace period that needs help */
223
-					/*  from cond_resched(). */
224
-
225
-	/* 5) _rcu_barrier(), OOM callbacks, and expediting. */
226
-	struct rcu_head barrier_head;
183
+	long dynticks_nesting;		/* Track process nesting level. */
184
+	long dynticks_nmi_nesting;	/* Track irq/NMI nesting level. */
185
+	atomic_t dynticks;		/* Even value for idle, else odd. */
186
+	bool rcu_need_heavy_qs;		/* GP old, so heavy quiescent state! */
187
+	bool rcu_urgent_qs;		/* GP old need light quiescent state. */
188
+	bool rcu_forced_tick;		/* Forced tick to provide QS. */
189
+	bool rcu_forced_tick_exp;	/*   ... provide QS to expedited GP. */
227190 #ifdef CONFIG_RCU_FAST_NO_HZ
228
-	struct rcu_head oom_head;
191
+	unsigned long last_accelerate;	/* Last jiffy CBs were accelerated. */
192
+	unsigned long last_advance_all;	/* Last jiffy CBs were all advanced. */
193
+	int tick_nohz_enabled_snap;	/* Previously seen value from sysfs. */
229194 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
195
+
196
+	/* 4) rcu_barrier(), OOM callbacks, and expediting. */
197
+	struct rcu_head barrier_head;
230198 	int exp_dynticks_snap;		/* Double-check need for IPI. */
231199 
232
-	/* 6) Callback offloading. */
200
+	/* 5) Callback offloading. */
233201 #ifdef CONFIG_RCU_NOCB_CPU
234
-	struct rcu_head *nocb_head;	/* CBs waiting for kthread. */
235
-	struct rcu_head **nocb_tail;
236
-	atomic_long_t nocb_q_count;	/* # CBs waiting for nocb */
237
-	atomic_long_t nocb_q_count_lazy; /*  invocation (all stages). */
238
-	struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */
239
-	struct rcu_head **nocb_follower_tail;
240
-	struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */
241
-	struct task_struct *nocb_kthread;
202
+	struct swait_queue_head nocb_cb_wq; /* For nocb kthreads to sleep on. */
203
+	struct task_struct *nocb_gp_kthread;
242204 	raw_spinlock_t nocb_lock;	/* Guard following pair of fields. */
205
+	atomic_t nocb_lock_contended;	/* Contention experienced. */
243206 	int nocb_defer_wakeup;		/* Defer wakeup of nocb_kthread. */
244207 	struct timer_list nocb_timer;	/* Enforce finite deferral. */
208
+	unsigned long nocb_gp_adv_time;	/* Last call_rcu() CB adv (jiffies). */
245209 
246
-	/* The following fields are used by the leader, hence own cacheline. */
247
-	struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp;
248
-					/* CBs waiting for GP. */
249
-	struct rcu_head **nocb_gp_tail;
250
-	bool nocb_leader_sleep;		/* Is the nocb leader thread asleep? */
251
-	struct rcu_data *nocb_next_follower;
252
-					/* Next follower in wakeup chain. */
210
+	/* The following fields are used by call_rcu, hence own cacheline. */
211
+	raw_spinlock_t nocb_bypass_lock ____cacheline_internodealigned_in_smp;
212
+	struct rcu_cblist nocb_bypass;	/* Lock-contention-bypass CB list. */
213
+	unsigned long nocb_bypass_first; /* Time (jiffies) of first enqueue. */
214
+	unsigned long nocb_nobypass_last; /* Last ->cblist enqueue (jiffies). */
215
+	int nocb_nobypass_count;	/* # ->cblist enqueues at ^^^ time. */
253216 
254
-	/* The following fields are used by the follower, hence new cachline. */
255
-	struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp;
256
-					/* Leader CPU takes GP-end wakeups. */
217
+	/* The following fields are used by GP kthread, hence own cacheline. */
218
+	raw_spinlock_t nocb_gp_lock ____cacheline_internodealigned_in_smp;
219
+	struct timer_list nocb_bypass_timer; /* Force nocb_bypass flush. */
220
+	u8 nocb_gp_sleep;		/* Is the nocb GP thread asleep? */
221
+	u8 nocb_gp_bypass;		/* Found a bypass on last scan? */
222
+	u8 nocb_gp_gp;			/* GP to wait for on last scan? */
223
+	unsigned long nocb_gp_seq;	/*  If so, ->gp_seq to wait for. */
224
+	unsigned long nocb_gp_loops;	/* # passes through wait code. */
225
+	struct swait_queue_head nocb_gp_wq; /* For nocb kthreads to sleep on. */
226
+	bool nocb_cb_sleep;		/* Is the nocb CB thread asleep? */
227
+	struct task_struct *nocb_cb_kthread;
228
+	struct rcu_data *nocb_next_cb_rdp;
229
+					/* Next rcu_data in wakeup chain. */
230
+
231
+	/* The following fields are used by CB kthread, hence new cacheline. */
232
+	struct rcu_data *nocb_gp_rdp ____cacheline_internodealigned_in_smp;
233
+					/* GP rdp takes GP-end wakeups. */
257234 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */
235
+
236
+	/* 6) RCU priority boosting. */
237
+	struct task_struct *rcu_cpu_kthread_task;
238
+					/* rcuc per-CPU kthread or NULL. */
239
+	unsigned int rcu_cpu_kthread_status;
240
+	char rcu_cpu_has_work;
258241 
259242 	/* 7) Diagnostic data, including RCU CPU stall warnings. */
260243 	unsigned int softirq_snap;	/* Snapshot of softirq activity. */
....@@ -266,9 +249,9 @@
266249 	short rcu_ofl_gp_flags;		/* ->gp_flags at last offline. */
267250 	unsigned long rcu_onl_gp_seq;	/* ->gp_seq at last online. */
268251 	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
252
+	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
269253 
270254 	int cpu;
271
-	struct rcu_state *rsp;
272255 };
273256 
274257 /* Values for nocb_defer_wakeup field in struct rcu_data. */
....@@ -314,8 +297,6 @@
314297 	struct rcu_node *level[RCU_NUM_LVLS + 1];
315298 						/* Hierarchy levels (+1 to */
316299 						/*  shut bogus gcc warning) */
317
-	struct rcu_data __percpu *rda;		/* pointer of percu rcu_data. */
318
-	call_rcu_func_t call;			/* call_rcu() flavor. */
319300 	int ncpus;				/* # CPUs seen so far. */
320301 
321302 	/* The following fields are guarded by the root rcu_node's lock. */
....@@ -323,10 +304,14 @@
323304 	u8	boost ____cacheline_internodealigned_in_smp;
324305 						/* Subject to priority boost. */
325306 	unsigned long gp_seq;			/* Grace-period sequence #. */
307
+	unsigned long gp_max;			/* Maximum GP duration in */
308
+						/*  jiffies. */
326309 	struct task_struct *gp_kthread;		/* Task for grace periods. */
327310 	struct swait_queue_head gp_wq;		/* Where GP task waits. */
328311 	short gp_flags;				/* Commands for GP task. */
329312 	short gp_state;				/* GP kthread sleep state. */
313
+	unsigned long gp_wake_time;		/* Last GP kthread wake. */
314
+	unsigned long gp_wake_seq;		/* ->gp_seq at ^^^. */
330315 
331316 	/* End of fields guarded by root rcu_node's lock. */
332317 
....@@ -334,7 +319,7 @@
334319 	atomic_t barrier_cpu_count;		/* # CPUs waiting on. */
335320 	struct completion barrier_completion;	/* Wake at barrier end. */
336321 	unsigned long barrier_sequence;		/* ++ at start and end of */
337
-						/*  _rcu_barrier(). */
322
+						/*  rcu_barrier(). */
338323 	/* End of fields guarded by barrier_mutex. */
339324 
340325 	struct mutex exp_mutex;			/* Serialize expedited GP. */
....@@ -343,6 +328,8 @@
343328 	atomic_t expedited_need_qs;		/* # CPUs left to check in. */
344329 	struct swait_queue_head expedited_wq;	/* Wait for check-ins. */
345330 	int ncpus_snap;				/* # CPUs seen last time. */
331
+	u8 cbovld;				/* Callback overload now? */
332
+	u8 cbovldnext;				/* ^        ^  next time? */
346333 
347334 	unsigned long jiffies_force_qs;		/* Time at which to invoke */
348335 						/*  force_quiescent_state(). */
....@@ -352,6 +339,8 @@
352339 						/*  force_quiescent_state(). */
353340 	unsigned long gp_start;			/* Time at which GP started, */
354341 						/*  but in jiffies. */
342
+	unsigned long gp_end;			/* Time last GP ended, again */
343
+						/*  in jiffies. */
355344 	unsigned long gp_activity;		/* Time of last GP kthread */
356345 						/*  activity in jiffies. */
357346 	unsigned long gp_req_activity;		/* Time of last GP request */
....@@ -362,13 +351,10 @@
362351 						/*  a reluctant CPU. */
363352 	unsigned long n_force_qs_gpstart;	/* Snapshot of n_force_qs at */
364353 						/*  GP start. */
365
-	unsigned long gp_max;			/* Maximum GP duration in */
366
-						/*  jiffies. */
367354 	const char *name;			/* Name of structure. */
368355 	char abbr;				/* Abbreviated name. */
369
-	struct list_head flavors;		/* List of RCU flavors. */
370356 
371
-	spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
357
+	raw_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
372358 						/* Synchronize offline with */
373359 						/*  GP pre-initialization. */
374360 };
....@@ -376,6 +362,7 @@
376362 /* Values for rcu_state structure's gp_flags field. */
377363 #define RCU_GP_FLAG_INIT 0x1	/* Need grace-period initialization. */
378364 #define RCU_GP_FLAG_FQS  0x2	/* Need grace-period quiescent-state forcing. */
365
+#define RCU_GP_FLAG_OVLD 0x4	/* Experiencing callback overload. */
379366 
380367 /* Values for rcu_state structure's gp_state field. */
381368 #define RCU_GP_IDLE	 0	/* Initial state and no GP in progress. */
....@@ -388,113 +375,95 @@
388375 #define RCU_GP_CLEANUP   7	/* Grace-period cleanup started. */
389376 #define RCU_GP_CLEANED   8	/* Grace-period cleanup complete. */
390377 
391
-#ifndef RCU_TREE_NONCORE
392
-static const char * const gp_state_names[] = {
393
-	"RCU_GP_IDLE",
394
-	"RCU_GP_WAIT_GPS",
395
-	"RCU_GP_DONE_GPS",
396
-	"RCU_GP_ONOFF",
397
-	"RCU_GP_INIT",
398
-	"RCU_GP_WAIT_FQS",
399
-	"RCU_GP_DOING_FQS",
400
-	"RCU_GP_CLEANUP",
401
-	"RCU_GP_CLEANED",
402
-};
403
-#endif /* #ifndef RCU_TREE_NONCORE */
404
-
405
-extern struct list_head rcu_struct_flavors;
406
-
407
-/* Sequence through rcu_state structures for each RCU flavor. */
408
-#define for_each_rcu_flavor(rsp) \
409
-	list_for_each_entry((rsp), &rcu_struct_flavors, flavors)
410
-
411378 /*
412
- * RCU implementation internal declarations:
379
+ * In order to export the rcu_state name to the tracing tools, it
380
+ * needs to be added in the __tracepoint_string section.
381
+ * This requires defining a separate variable tp_<sname>_varname
382
+ * that points to the string being used, and this will allow
383
+ * the tracing userspace tools to be able to decipher the string
384
+ * address to the matching string.
413385  */
414
-extern struct rcu_state rcu_sched_state;
415
-
416
-extern struct rcu_state rcu_bh_state;
417
-
418386 #ifdef CONFIG_PREEMPT_RCU
419
-extern struct rcu_state rcu_preempt_state;
420
-#endif /* #ifdef CONFIG_PREEMPT_RCU */
387
+#define RCU_ABBR 'p'
388
+#define RCU_NAME_RAW "rcu_preempt"
389
+#else /* #ifdef CONFIG_PREEMPT_RCU */
390
+#define RCU_ABBR 's'
391
+#define RCU_NAME_RAW "rcu_sched"
392
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
393
+#ifndef CONFIG_TRACING
394
+#define RCU_NAME RCU_NAME_RAW
395
+#else /* #ifdef CONFIG_TRACING */
396
+static char rcu_name[] = RCU_NAME_RAW;
397
+static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
398
+#define RCU_NAME rcu_name
399
+#endif /* #else #ifdef CONFIG_TRACING */
421400 
422
-int rcu_dynticks_snap(struct rcu_dynticks *rdtp);
423
-
424
-#ifdef CONFIG_RCU_BOOST
425
-DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
426
-DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
427
-DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
428
-DECLARE_PER_CPU(char, rcu_cpu_has_work);
429
-#endif /* #ifdef CONFIG_RCU_BOOST */
430
-
431
-#ifndef RCU_TREE_NONCORE
432
-
433
-/* Forward declarations for rcutree_plugin.h */
401
+/* Forward declarations for tree_plugin.h */
434402 static void rcu_bootup_announce(void);
435
-static void rcu_preempt_note_context_switch(bool preempt);
403
+static void rcu_qs(void);
436404 static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
437405 #ifdef CONFIG_HOTPLUG_CPU
438406 static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
439407 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
440
-static void rcu_print_detail_task_stall(struct rcu_state *rsp);
441
-static int rcu_print_task_stall(struct rcu_node *rnp);
442408 static int rcu_print_task_exp_stall(struct rcu_node *rnp);
443
-static void rcu_preempt_check_blocked_tasks(struct rcu_state *rsp,
444
-					    struct rcu_node *rnp);
445
-static void rcu_preempt_check_callbacks(void);
446
-void call_rcu(struct rcu_head *head, rcu_callback_t func);
447
-static void __init __rcu_init_preempt(void);
448
-static void dump_blkd_tasks(struct rcu_state *rsp, struct rcu_node *rnp,
449
-			    int ncheck);
409
+static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
410
+static void rcu_flavor_sched_clock_irq(int user);
411
+static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck);
450412 static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
451413 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
452
-static void invoke_rcu_callbacks_kthread(void);
453414 static bool rcu_is_callbacks_kthread(void);
454
-#ifdef CONFIG_RCU_BOOST
455
-static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
456
-						 struct rcu_node *rnp);
457
-#endif /* #ifdef CONFIG_RCU_BOOST */
415
+static void rcu_cpu_kthread_setup(unsigned int cpu);
458416 static void __init rcu_spawn_boost_kthreads(void);
459417 static void rcu_prepare_kthreads(int cpu);
460418 static void rcu_cleanup_after_idle(void);
461419 static void rcu_prepare_for_idle(void);
462
-static void rcu_idle_count_callbacks_posted(void);
463420 static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
464
-static void print_cpu_stall_info_begin(void);
465
-static void print_cpu_stall_info(struct rcu_state *rsp, int cpu);
466
-static void print_cpu_stall_info_end(void);
421
+static bool rcu_preempt_need_deferred_qs(struct task_struct *t);
422
+static void rcu_preempt_deferred_qs(struct task_struct *t);
467423 static void zero_cpu_stall_ticks(struct rcu_data *rdp);
468
-static void increment_cpu_stall_ticks(void);
469
-static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu);
470424 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
471425 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
472426 static void rcu_init_one_nocb(struct rcu_node *rnp);
473
-static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
474
-			    bool lazy, unsigned long flags);
475
-static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp,
476
-				      struct rcu_data *rdp,
477
-				      unsigned long flags);
427
+static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
428
+				  unsigned long j);
429
+static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
430
+				bool *was_alldone, unsigned long flags);
431
+static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty,
432
+				 unsigned long flags);
478433 static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
479434 static void do_nocb_deferred_wakeup(struct rcu_data *rdp);
480435 static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
481
-static void rcu_spawn_all_nocb_kthreads(int cpu);
436
+static void rcu_spawn_cpu_nocb_kthread(int cpu);
482437 static void __init rcu_spawn_nocb_kthreads(void);
438
+static void show_rcu_nocb_state(struct rcu_data *rdp);
439
+static void rcu_nocb_lock(struct rcu_data *rdp);
440
+static void rcu_nocb_unlock(struct rcu_data *rdp);
441
+static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
442
+				       unsigned long flags);
443
+static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp);
483444 #ifdef CONFIG_RCU_NOCB_CPU
484
-static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp);
485
-#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
486
-static bool init_nocb_callback_list(struct rcu_data *rdp);
445
+static void __init rcu_organize_nocb_kthreads(void);
446
+#define rcu_nocb_lock_irqsave(rdp, flags)				\
447
+do {									\
448
+	if (!rcu_segcblist_is_offloaded(&(rdp)->cblist))		\
449
+		local_irq_save(flags);					\
450
+	else								\
451
+		raw_spin_lock_irqsave(&(rdp)->nocb_lock, (flags));	\
452
+} while (0)
453
+#else /* #ifdef CONFIG_RCU_NOCB_CPU */
454
+#define rcu_nocb_lock_irqsave(rdp, flags) local_irq_save(flags)
455
+#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
456
+
487457 static void rcu_bind_gp_kthread(void);
488
-static bool rcu_nohz_full_cpu(struct rcu_state *rsp);
458
+static bool rcu_nohz_full_cpu(void);
489459 static void rcu_dynticks_task_enter(void);
490460 static void rcu_dynticks_task_exit(void);
461
+static void rcu_dynticks_task_trace_enter(void);
462
+static void rcu_dynticks_task_trace_exit(void);
491463 
492
-#ifdef CONFIG_SRCU
493
-void srcu_online_cpu(unsigned int cpu);
494
-void srcu_offline_cpu(unsigned int cpu);
495
-#else /* #ifdef CONFIG_SRCU */
496
-void srcu_online_cpu(unsigned int cpu) { }
497
-void srcu_offline_cpu(unsigned int cpu) { }
498
-#endif /* #else #ifdef CONFIG_SRCU */
499
-
500
-#endif /* #ifndef RCU_TREE_NONCORE */
464
+/* Forward declarations for tree_stall.h */
465
+static void record_gp_stall_check_time(void);
466
+static void rcu_iw_handler(struct irq_work *iwp);
467
+static void check_cpu_stall(struct rcu_data *rdp);
468
+static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
469
+				     const unsigned long gpssdelay);