~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/kernel/rcu/update.c

Version: ~ [ linux-6.0-rc1 ] ~ [ linux-5.19.1 ] ~ [ linux-5.18.17 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.60 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.136 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.210 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.255 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.290 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.325 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.302 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0+
  2 /*
  3  * Read-Copy Update mechanism for mutual exclusion
  4  *
  5  * Copyright IBM Corporation, 2001
  6  *
  7  * Authors: Dipankar Sarma <dipankar@in.ibm.com>
  8  *          Manfred Spraul <manfred@colorfullife.com>
  9  *
 10  * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
 11  * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
 12  * Papers:
 13  * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf
 14  * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001)
 15  *
 16  * For detailed explanation of Read-Copy Update mechanism see -
 17  *              http://lse.sourceforge.net/locking/rcupdate.html
 18  *
 19  */
 20 #include <linux/types.h>
 21 #include <linux/kernel.h>
 22 #include <linux/init.h>
 23 #include <linux/spinlock.h>
 24 #include <linux/smp.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/sched/signal.h>
 27 #include <linux/sched/debug.h>
 28 #include <linux/atomic.h>
 29 #include <linux/bitops.h>
 30 #include <linux/percpu.h>
 31 #include <linux/notifier.h>
 32 #include <linux/cpu.h>
 33 #include <linux/mutex.h>
 34 #include <linux/export.h>
 35 #include <linux/hardirq.h>
 36 #include <linux/delay.h>
 37 #include <linux/moduleparam.h>
 38 #include <linux/kthread.h>
 39 #include <linux/tick.h>
 40 #include <linux/rcupdate_wait.h>
 41 #include <linux/sched/isolation.h>
 42 #include <linux/kprobes.h>
 43 #include <linux/slab.h>
 44 #include <linux/irq_work.h>
 45 #include <linux/rcupdate_trace.h>
 46 
 47 #define CREATE_TRACE_POINTS
 48 
 49 #include "rcu.h"
 50 
 51 #ifdef MODULE_PARAM_PREFIX
 52 #undef MODULE_PARAM_PREFIX
 53 #endif
 54 #define MODULE_PARAM_PREFIX "rcupdate."
 55 
 56 #ifndef CONFIG_TINY_RCU
 57 module_param(rcu_expedited, int, 0444);
 58 module_param(rcu_normal, int, 0444);
 59 static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
 60 #if !defined(CONFIG_PREEMPT_RT) || defined(CONFIG_NO_HZ_FULL)
 61 module_param(rcu_normal_after_boot, int, 0444);
 62 #endif
 63 #endif /* #ifndef CONFIG_TINY_RCU */
 64 
 65 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 66 /**
 67  * rcu_read_lock_held_common() - might we be in RCU-sched read-side critical section?
 68  * @ret:        Best guess answer if lockdep cannot be relied on
 69  *
 70  * Returns true if lockdep must be ignored, in which case ``*ret`` contains
 71  * the best guess described below.  Otherwise returns false, in which
 72  * case ``*ret`` tells the caller nothing and the caller should instead
 73  * consult lockdep.
 74  *
 75  * If CONFIG_DEBUG_LOCK_ALLOC is selected, set ``*ret`` to nonzero iff in an
 76  * RCU-sched read-side critical section.  In absence of
 77  * CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side
 78  * critical section unless it can prove otherwise.  Note that disabling
 79  * of preemption (including disabling irqs) counts as an RCU-sched
 80  * read-side critical section.  This is useful for debug checks in functions
 81  * that required that they be called within an RCU-sched read-side
 82  * critical section.
 83  *
 84  * Check debug_lockdep_rcu_enabled() to prevent false positives during boot
 85  * and while lockdep is disabled.
 86  *
 87  * Note that if the CPU is in the idle loop from an RCU point of view (ie:
 88  * that we are in the section between rcu_idle_enter() and rcu_idle_exit())
 89  * then rcu_read_lock_held() sets ``*ret`` to false even if the CPU did an
 90  * rcu_read_lock().  The reason for this is that RCU ignores CPUs that are
 91  * in such a section, considering these as in extended quiescent state,
 92  * so such a CPU is effectively never in an RCU read-side critical section
 93  * regardless of what RCU primitives it invokes.  This state of affairs is
 94  * required --- we need to keep an RCU-free window in idle where the CPU may
 95  * possibly enter into low power mode. This way we can notice an extended
 96  * quiescent state to other CPUs that started a grace period. Otherwise
 97  * we would delay any grace period as long as we run in the idle task.
 98  *
 99  * Similarly, we avoid claiming an RCU read lock held if the current
100  * CPU is offline.
101  */
102 static bool rcu_read_lock_held_common(bool *ret)
103 {
104         if (!debug_lockdep_rcu_enabled()) {
105                 *ret = true;
106                 return true;
107         }
108         if (!rcu_is_watching()) {
109                 *ret = false;
110                 return true;
111         }
112         if (!rcu_lockdep_current_cpu_online()) {
113                 *ret = false;
114                 return true;
115         }
116         return false;
117 }
118 
119 int rcu_read_lock_sched_held(void)
120 {
121         bool ret;
122 
123         if (rcu_read_lock_held_common(&ret))
124                 return ret;
125         return lock_is_held(&rcu_sched_lock_map) || !preemptible();
126 }
127 EXPORT_SYMBOL(rcu_read_lock_sched_held);
128 #endif
129 
130 #ifndef CONFIG_TINY_RCU
131 
132 /*
133  * Should expedited grace-period primitives always fall back to their
134  * non-expedited counterparts?  Intended for use within RCU.  Note
135  * that if the user specifies both rcu_expedited and rcu_normal, then
136  * rcu_normal wins.  (Except during the time period during boot from
137  * when the first task is spawned until the rcu_set_runtime_mode()
138  * core_initcall() is invoked, at which point everything is expedited.)
139  */
140 bool rcu_gp_is_normal(void)
141 {
142         return READ_ONCE(rcu_normal) &&
143                rcu_scheduler_active != RCU_SCHEDULER_INIT;
144 }
145 EXPORT_SYMBOL_GPL(rcu_gp_is_normal);
146 
147 static atomic_t rcu_expedited_nesting = ATOMIC_INIT(1);
148 
149 /*
150  * Should normal grace-period primitives be expedited?  Intended for
151  * use within RCU.  Note that this function takes the rcu_expedited
152  * sysfs/boot variable and rcu_scheduler_active into account as well
153  * as the rcu_expedite_gp() nesting.  So looping on rcu_unexpedite_gp()
154  * until rcu_gp_is_expedited() returns false is a -really- bad idea.
155  */
156 bool rcu_gp_is_expedited(void)
157 {
158         return rcu_expedited || atomic_read(&rcu_expedited_nesting);
159 }
160 EXPORT_SYMBOL_GPL(rcu_gp_is_expedited);
161 
162 /**
163  * rcu_expedite_gp - Expedite future RCU grace periods
164  *
165  * After a call to this function, future calls to synchronize_rcu() and
166  * friends act as the corresponding synchronize_rcu_expedited() function
167  * had instead been called.
168  */
169 void rcu_expedite_gp(void)
170 {
171         atomic_inc(&rcu_expedited_nesting);
172 }
173 EXPORT_SYMBOL_GPL(rcu_expedite_gp);
174 
175 /**
176  * rcu_unexpedite_gp - Cancel prior rcu_expedite_gp() invocation
177  *
178  * Undo a prior call to rcu_expedite_gp().  If all prior calls to
179  * rcu_expedite_gp() are undone by a subsequent call to rcu_unexpedite_gp(),
180  * and if the rcu_expedited sysfs/boot parameter is not set, then all
181  * subsequent calls to synchronize_rcu() and friends will return to
182  * their normal non-expedited behavior.
183  */
184 void rcu_unexpedite_gp(void)
185 {
186         atomic_dec(&rcu_expedited_nesting);
187 }
188 EXPORT_SYMBOL_GPL(rcu_unexpedite_gp);
189 
190 static bool rcu_boot_ended __read_mostly;
191 
192 /*
193  * Inform RCU of the end of the in-kernel boot sequence.
194  */
195 void rcu_end_inkernel_boot(void)
196 {
197         rcu_unexpedite_gp();
198         if (rcu_normal_after_boot)
199                 WRITE_ONCE(rcu_normal, 1);
200         rcu_boot_ended = true;
201 }
202 
203 /*
204  * Let rcutorture know when it is OK to turn it up to eleven.
205  */
206 bool rcu_inkernel_boot_has_ended(void)
207 {
208         return rcu_boot_ended;
209 }
210 EXPORT_SYMBOL_GPL(rcu_inkernel_boot_has_ended);
211 
212 #endif /* #ifndef CONFIG_TINY_RCU */
213 
214 /*
215  * Test each non-SRCU synchronous grace-period wait API.  This is
216  * useful just after a change in mode for these primitives, and
217  * during early boot.
218  */
219 void rcu_test_sync_prims(void)
220 {
221         if (!IS_ENABLED(CONFIG_PROVE_RCU))
222                 return;
223         synchronize_rcu();
224         synchronize_rcu_expedited();
225 }
226 
227 #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU)
228 
229 /*
230  * Switch to run-time mode once RCU has fully initialized.
231  */
232 static int __init rcu_set_runtime_mode(void)
233 {
234         rcu_test_sync_prims();
235         rcu_scheduler_active = RCU_SCHEDULER_RUNNING;
236         kfree_rcu_scheduler_running();
237         rcu_test_sync_prims();
238         return 0;
239 }
240 core_initcall(rcu_set_runtime_mode);
241 
242 #endif /* #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU) */
243 
244 #ifdef CONFIG_DEBUG_LOCK_ALLOC
245 static struct lock_class_key rcu_lock_key;
246 struct lockdep_map rcu_lock_map = {
247         .name = "rcu_read_lock",
248         .key = &rcu_lock_key,
249         .wait_type_outer = LD_WAIT_FREE,
250         .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT implies PREEMPT_RCU */
251 };
252 EXPORT_SYMBOL_GPL(rcu_lock_map);
253 
254 static struct lock_class_key rcu_bh_lock_key;
255 struct lockdep_map rcu_bh_lock_map = {
256         .name = "rcu_read_lock_bh",
257         .key = &rcu_bh_lock_key,
258         .wait_type_outer = LD_WAIT_FREE,
259         .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */
260 };
261 EXPORT_SYMBOL_GPL(rcu_bh_lock_map);
262 
263 static struct lock_class_key rcu_sched_lock_key;
264 struct lockdep_map rcu_sched_lock_map = {
265         .name = "rcu_read_lock_sched",
266         .key = &rcu_sched_lock_key,
267         .wait_type_outer = LD_WAIT_FREE,
268         .wait_type_inner = LD_WAIT_SPIN,
269 };
270 EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
271 
272 // Tell lockdep when RCU callbacks are being invoked.
273 static struct lock_class_key rcu_callback_key;
274 struct lockdep_map rcu_callback_map =
275         STATIC_LOCKDEP_MAP_INIT("rcu_callback", &rcu_callback_key);
276 EXPORT_SYMBOL_GPL(rcu_callback_map);
277 
278 noinstr int notrace debug_lockdep_rcu_enabled(void)
279 {
280         return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && READ_ONCE(debug_locks) &&
281                current->lockdep_recursion == 0;
282 }
283 EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
284 
285 /**
286  * rcu_read_lock_held() - might we be in RCU read-side critical section?
287  *
288  * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an RCU
289  * read-side critical section.  In absence of CONFIG_DEBUG_LOCK_ALLOC,
290  * this assumes we are in an RCU read-side critical section unless it can
291  * prove otherwise.  This is useful for debug checks in functions that
292  * require that they be called within an RCU read-side critical section.
293  *
294  * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
295  * and while lockdep is disabled.
296  *
297  * Note that rcu_read_lock() and the matching rcu_read_unlock() must
298  * occur in the same context, for example, it is illegal to invoke
299  * rcu_read_unlock() in process context if the matching rcu_read_lock()
300  * was invoked from within an irq handler.
301  *
302  * Note that rcu_read_lock() is disallowed if the CPU is either idle or
303  * offline from an RCU perspective, so check for those as well.
304  */
305 int rcu_read_lock_held(void)
306 {
307         bool ret;
308 
309         if (rcu_read_lock_held_common(&ret))
310                 return ret;
311         return lock_is_held(&rcu_lock_map);
312 }
313 EXPORT_SYMBOL_GPL(rcu_read_lock_held);
314 
315 /**
316  * rcu_read_lock_bh_held() - might we be in RCU-bh read-side critical section?
317  *
318  * Check for bottom half being disabled, which covers both the
319  * CONFIG_PROVE_RCU and not cases.  Note that if someone uses
320  * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled)
321  * will show the situation.  This is useful for debug checks in functions
322  * that require that they be called within an RCU read-side critical
323  * section.
324  *
325  * Check debug_lockdep_rcu_enabled() to prevent false positives during boot.
326  *
327  * Note that rcu_read_lock_bh() is disallowed if the CPU is either idle or
328  * offline from an RCU perspective, so check for those as well.
329  */
330 int rcu_read_lock_bh_held(void)
331 {
332         bool ret;
333 
334         if (rcu_read_lock_held_common(&ret))
335                 return ret;
336         return in_softirq() || irqs_disabled();
337 }
338 EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
339 
340 int rcu_read_lock_any_held(void)
341 {
342         bool ret;
343 
344         if (rcu_read_lock_held_common(&ret))
345                 return ret;
346         if (lock_is_held(&rcu_lock_map) ||
347             lock_is_held(&rcu_bh_lock_map) ||
348             lock_is_held(&rcu_sched_lock_map))
349                 return 1;
350         return !preemptible();
351 }
352 EXPORT_SYMBOL_GPL(rcu_read_lock_any_held);
353 
354 #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
355 
356 /**
357  * wakeme_after_rcu() - Callback function to awaken a task after grace period
358  * @head: Pointer to rcu_head member within rcu_synchronize structure
359  *
360  * Awaken the corresponding task now that a grace period has elapsed.
361  */
362 void wakeme_after_rcu(struct rcu_head *head)
363 {
364         struct rcu_synchronize *rcu;
365 
366         rcu = container_of(head, struct rcu_synchronize, head);
367         complete(&rcu->completion);
368 }
369 EXPORT_SYMBOL_GPL(wakeme_after_rcu);
370 
371 void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
372                    struct rcu_synchronize *rs_array)
373 {
374         int i;
375         int j;
376 
377         /* Initialize and register callbacks for each crcu_array element. */
378         for (i = 0; i < n; i++) {
379                 if (checktiny &&
380                     (crcu_array[i] == call_rcu)) {
381                         might_sleep();
382                         continue;
383                 }
384                 for (j = 0; j < i; j++)
385                         if (crcu_array[j] == crcu_array[i])
386                                 break;
387                 if (j == i) {
388                         init_rcu_head_on_stack(&rs_array[i].head);
389                         init_completion(&rs_array[i].completion);
390                         (crcu_array[i])(&rs_array[i].head, wakeme_after_rcu);
391                 }
392         }
393 
394         /* Wait for all callbacks to be invoked. */
395         for (i = 0; i < n; i++) {
396                 if (checktiny &&
397                     (crcu_array[i] == call_rcu))
398                         continue;
399                 for (j = 0; j < i; j++)
400                         if (crcu_array[j] == crcu_array[i])
401                                 break;
402                 if (j == i) {
403                         wait_for_completion(&rs_array[i].completion);
404                         destroy_rcu_head_on_stack(&rs_array[i].head);
405                 }
406         }
407 }
408 EXPORT_SYMBOL_GPL(__wait_rcu_gp);
409 
410 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
411 void init_rcu_head(struct rcu_head *head)
412 {
413         debug_object_init(head, &rcuhead_debug_descr);
414 }
415 EXPORT_SYMBOL_GPL(init_rcu_head);
416 
417 void destroy_rcu_head(struct rcu_head *head)
418 {
419         debug_object_free(head, &rcuhead_debug_descr);
420 }
421 EXPORT_SYMBOL_GPL(destroy_rcu_head);
422 
423 static bool rcuhead_is_static_object(void *addr)
424 {
425         return true;
426 }
427 
428 /**
429  * init_rcu_head_on_stack() - initialize on-stack rcu_head for debugobjects
430  * @head: pointer to rcu_head structure to be initialized
431  *
432  * This function informs debugobjects of a new rcu_head structure that
433  * has been allocated as an auto variable on the stack.  This function
434  * is not required for rcu_head structures that are statically defined or
435  * that are dynamically allocated on the heap.  This function has no
436  * effect for !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds.
437  */
438 void init_rcu_head_on_stack(struct rcu_head *head)
439 {
440         debug_object_init_on_stack(head, &rcuhead_debug_descr);
441 }
442 EXPORT_SYMBOL_GPL(init_rcu_head_on_stack);
443 
444 /**
445  * destroy_rcu_head_on_stack() - destroy on-stack rcu_head for debugobjects
446  * @head: pointer to rcu_head structure to be initialized
447  *
448  * This function informs debugobjects that an on-stack rcu_head structure
449  * is about to go out of scope.  As with init_rcu_head_on_stack(), this
450  * function is not required for rcu_head structures that are statically
451  * defined or that are dynamically allocated on the heap.  Also as with
452  * init_rcu_head_on_stack(), this function has no effect for
453  * !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds.
454  */
455 void destroy_rcu_head_on_stack(struct rcu_head *head)
456 {
457         debug_object_free(head, &rcuhead_debug_descr);
458 }
459 EXPORT_SYMBOL_GPL(destroy_rcu_head_on_stack);
460 
461 const struct debug_obj_descr rcuhead_debug_descr = {
462         .name = "rcu_head",
463         .is_static_object = rcuhead_is_static_object,
464 };
465 EXPORT_SYMBOL_GPL(rcuhead_debug_descr);
466 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
467 
468 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_RCU_TRACE)
469 void do_trace_rcu_torture_read(const char *rcutorturename, struct rcu_head *rhp,
470                                unsigned long secs,
471                                unsigned long c_old, unsigned long c)
472 {
473         trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c);
474 }
475 EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read);
476 #else
477 #define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
478         do { } while (0)
479 #endif
480 
481 #if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
482 /* Get rcutorture access to sched_setaffinity(). */
483 long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
484 {
485         int ret;
486 
487         ret = sched_setaffinity(pid, in_mask);
488         WARN_ONCE(ret, "%s: sched_setaffinity() returned %d\n", __func__, ret);
489         return ret;
490 }
491 EXPORT_SYMBOL_GPL(rcutorture_sched_setaffinity);
492 #endif
493 
494 #ifdef CONFIG_RCU_STALL_COMMON
495 int rcu_cpu_stall_ftrace_dump __read_mostly;
496 module_param(rcu_cpu_stall_ftrace_dump, int, 0644);
497 int rcu_cpu_stall_suppress __read_mostly; // !0 = suppress stall warnings.
498 EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress);
499 module_param(rcu_cpu_stall_suppress, int, 0644);
500 int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
501 module_param(rcu_cpu_stall_timeout, int, 0644);
502 #endif /* #ifdef CONFIG_RCU_STALL_COMMON */
503 
504 // Suppress boot-time RCU CPU stall warnings and rcutorture writer stall
505 // warnings.  Also used by rcutorture even if stall warnings are excluded.
506 int rcu_cpu_stall_suppress_at_boot __read_mostly; // !0 = suppress boot stalls.
507 EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress_at_boot);
508 module_param(rcu_cpu_stall_suppress_at_boot, int, 0444);
509 
510 #ifdef CONFIG_PROVE_RCU
511 
512 /*
513  * Early boot self test parameters.
514  */
515 static bool rcu_self_test;
516 module_param(rcu_self_test, bool, 0444);
517 
518 static int rcu_self_test_counter;
519 
520 static void test_callback(struct rcu_head *r)
521 {
522         rcu_self_test_counter++;
523         pr_info("RCU test callback executed %d\n", rcu_self_test_counter);
524 }
525 
526 DEFINE_STATIC_SRCU(early_srcu);
527 static unsigned long early_srcu_cookie;
528 
529 struct early_boot_kfree_rcu {
530         struct rcu_head rh;
531 };
532 
533 static void early_boot_test_call_rcu(void)
534 {
535         static struct rcu_head head;
536         static struct rcu_head shead;
537         struct early_boot_kfree_rcu *rhp;
538 
539         call_rcu(&head, test_callback);
540         if (IS_ENABLED(CONFIG_SRCU)) {
541                 early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu);
542                 call_srcu(&early_srcu, &shead, test_callback);
543         }
544         rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
545         if (!WARN_ON_ONCE(!rhp))
546                 kfree_rcu(rhp, rh);
547 }
548 
549 void rcu_early_boot_tests(void)
550 {
551         pr_info("Running RCU self tests\n");
552 
553         if (rcu_self_test)
554                 early_boot_test_call_rcu();
555         rcu_test_sync_prims();
556 }
557 
558 static int rcu_verify_early_boot_tests(void)
559 {
560         int ret = 0;
561         int early_boot_test_counter = 0;
562 
563         if (rcu_self_test) {
564                 early_boot_test_counter++;
565                 rcu_barrier();
566                 if (IS_ENABLED(CONFIG_SRCU)) {
567                         early_boot_test_counter++;
568                         srcu_barrier(&early_srcu);
569                         WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie));
570                 }
571         }
572         if (rcu_self_test_counter != early_boot_test_counter) {
573                 WARN_ON(1);
574                 ret = -1;
575         }
576 
577         return ret;
578 }
579 late_initcall(rcu_verify_early_boot_tests);
580 #else
581 void rcu_early_boot_tests(void) {}
582 #endif /* CONFIG_PROVE_RCU */
583 
584 #include "tasks.h"
585 
586 #ifndef CONFIG_TINY_RCU
587 
588 /*
589  * Print any significant non-default boot-time settings.
590  */
591 void __init rcupdate_announce_bootup_oddness(void)
592 {
593         if (rcu_normal)
594                 pr_info("\tNo expedited grace period (rcu_normal).\n");
595         else if (rcu_normal_after_boot)
596                 pr_info("\tNo expedited grace period (rcu_normal_after_boot).\n");
597         else if (rcu_expedited)
598                 pr_info("\tAll grace periods are expedited (rcu_expedited).\n");
599         if (rcu_cpu_stall_suppress)
600                 pr_info("\tRCU CPU stall warnings suppressed (rcu_cpu_stall_suppress).\n");
601         if (rcu_cpu_stall_timeout != CONFIG_RCU_CPU_STALL_TIMEOUT)
602                 pr_info("\tRCU CPU stall warnings timeout set to %d (rcu_cpu_stall_timeout).\n", rcu_cpu_stall_timeout);
603         rcu_tasks_bootup_oddness();
604 }
605 
606 #endif /* #ifndef CONFIG_TINY_RCU */
607 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp