1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SCHED_H
3 #define _LINUX_SCHED_H
4 
5 /*
6  * Define 'struct task_struct' and provide the main scheduler
7  * APIs (schedule(), wakeup variants, etc.)
8  */
9 
10 #include <uapi/linux/sched.h>
11 
12 #include <asm/current.h>
13 
14 #include <linux/pid.h>
15 #include <linux/sem.h>
16 #include <linux/shm.h>
17 #include <linux/mutex.h>
18 #include <linux/plist.h>
19 #include <linux/hrtimer.h>
20 #include <linux/irqflags.h>
21 #include <linux/seccomp.h>
22 #include <linux/nodemask.h>
23 #include <linux/rcupdate.h>
24 #include <linux/refcount.h>
25 #include <linux/resource.h>
26 #include <linux/latencytop.h>
27 #include <linux/sched/prio.h>
28 #include <linux/sched/types.h>
29 #include <linux/signal_types.h>
30 #include <linux/syscall_user_dispatch.h>
31 #include <linux/mm_types_task.h>
32 #include <linux/task_io_accounting.h>
33 #include <linux/posix-timers.h>
34 #include <linux/rseq.h>
35 #include <linux/seqlock.h>
36 #include <linux/kcsan.h>
37 #include <asm/kmap_size.h>
38 
39 /* task_struct member predeclarations (sorted alphabetically): */
40 struct audit_context;
41 struct backing_dev_info;
42 struct bio_list;
43 struct blk_plug;
44 struct bpf_local_storage;
45 struct bpf_run_ctx;
46 struct capture_control;
47 struct cfs_rq;
48 struct fs_struct;
49 struct futex_pi_state;
50 struct io_context;
51 struct io_uring_task;
52 struct mempolicy;
53 struct nameidata;
54 struct nsproxy;
55 struct perf_event_context;
56 struct pid_namespace;
57 struct pipe_inode_info;
58 struct rcu_node;
59 struct reclaim_state;
60 struct robust_list_head;
61 struct root_domain;
62 struct rq;
63 struct sched_attr;
64 struct sched_param;
65 struct seq_file;
66 struct sighand_struct;
67 struct signal_struct;
68 struct task_delay_info;
69 struct task_group;
70 
71 /*
72  * Task state bitmask. NOTE! These bits are also
73  * encoded in fs/proc/array.c: get_task_state().
74  *
75  * We have two separate sets of flags: task->state
76  * is about runnability, while task->exit_state are
77  * about the task exiting. Confusing, but this way
78  * modifying one set can't modify the other one by
79  * mistake.
80  */
81 
82 /* Used in tsk->state: */
83 #define TASK_RUNNING			0x0000
84 #define TASK_INTERRUPTIBLE		0x0001
85 #define TASK_UNINTERRUPTIBLE		0x0002
86 #define __TASK_STOPPED			0x0004
87 #define __TASK_TRACED			0x0008
88 /* Used in tsk->exit_state: */
89 #define EXIT_DEAD			0x0010
90 #define EXIT_ZOMBIE			0x0020
91 #define EXIT_TRACE			(EXIT_ZOMBIE | EXIT_DEAD)
92 /* Used in tsk->state again: */
93 #define TASK_PARKED			0x0040
94 #define TASK_DEAD			0x0080
95 #define TASK_WAKEKILL			0x0100
96 #define TASK_WAKING			0x0200
97 #define TASK_NOLOAD			0x0400
98 #define TASK_NEW			0x0800
99 /* RT specific auxilliary flag to mark RT lock waiters */
100 #define TASK_RTLOCK_WAIT		0x1000
101 #define TASK_STATE_MAX			0x2000
102 
103 /* Convenience macros for the sake of set_current_state: */
104 #define TASK_KILLABLE			(TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
105 #define TASK_STOPPED			(TASK_WAKEKILL | __TASK_STOPPED)
106 #define TASK_TRACED			(TASK_WAKEKILL | __TASK_TRACED)
107 
108 #define TASK_IDLE			(TASK_UNINTERRUPTIBLE | TASK_NOLOAD)
109 
110 /* Convenience macros for the sake of wake_up(): */
111 #define TASK_NORMAL			(TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
112 
113 /* get_task_state(): */
114 #define TASK_REPORT			(TASK_RUNNING | TASK_INTERRUPTIBLE | \
115 					 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
116 					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
117 					 TASK_PARKED)
118 
119 #define task_is_running(task)		(READ_ONCE((task)->__state) == TASK_RUNNING)
120 
121 #define task_is_traced(task)		((READ_ONCE(task->__state) & __TASK_TRACED) != 0)
122 
123 #define task_is_stopped(task)		((READ_ONCE(task->__state) & __TASK_STOPPED) != 0)
124 
125 #define task_is_stopped_or_traced(task)	((READ_ONCE(task->__state) & (__TASK_STOPPED | __TASK_TRACED)) != 0)
126 
127 /*
128  * Special states are those that do not use the normal wait-loop pattern. See
129  * the comment with set_special_state().
130  */
131 #define is_special_task_state(state)				\
132 	((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | TASK_DEAD))
133 
134 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
135 # define debug_normal_state_change(state_value)				\
136 	do {								\
137 		WARN_ON_ONCE(is_special_task_state(state_value));	\
138 		current->task_state_change = _THIS_IP_;			\
139 	} while (0)
140 
141 # define debug_special_state_change(state_value)			\
142 	do {								\
143 		WARN_ON_ONCE(!is_special_task_state(state_value));	\
144 		current->task_state_change = _THIS_IP_;			\
145 	} while (0)
146 
147 # define debug_rtlock_wait_set_state()					\
148 	do {								 \
149 		current->saved_state_change = current->task_state_change;\
150 		current->task_state_change = _THIS_IP_;			 \
151 	} while (0)
152 
153 # define debug_rtlock_wait_restore_state()				\
154 	do {								 \
155 		current->task_state_change = current->saved_state_change;\
156 	} while (0)
157 
158 #else
159 # define debug_normal_state_change(cond)	do { } while (0)
160 # define debug_special_state_change(cond)	do { } while (0)
161 # define debug_rtlock_wait_set_state()		do { } while (0)
162 # define debug_rtlock_wait_restore_state()	do { } while (0)
163 #endif
164 
165 /*
166  * set_current_state() includes a barrier so that the write of current->state
167  * is correctly serialised wrt the caller's subsequent test of whether to
168  * actually sleep:
169  *
170  *   for (;;) {
171  *	set_current_state(TASK_UNINTERRUPTIBLE);
172  *	if (CONDITION)
173  *	   break;
174  *
175  *	schedule();
176  *   }
177  *   __set_current_state(TASK_RUNNING);
178  *
179  * If the caller does not need such serialisation (because, for instance, the
180  * CONDITION test and condition change and wakeup are under the same lock) then
181  * use __set_current_state().
182  *
183  * The above is typically ordered against the wakeup, which does:
184  *
185  *   CONDITION = 1;
186  *   wake_up_state(p, TASK_UNINTERRUPTIBLE);
187  *
188  * where wake_up_state()/try_to_wake_up() executes a full memory barrier before
189  * accessing p->state.
190  *
191  * Wakeup will do: if (@state & p->state) p->state = TASK_RUNNING, that is,
192  * once it observes the TASK_UNINTERRUPTIBLE store the waking CPU can issue a
193  * TASK_RUNNING store which can collide with __set_current_state(TASK_RUNNING).
194  *
195  * However, with slightly different timing the wakeup TASK_RUNNING store can
196  * also collide with the TASK_UNINTERRUPTIBLE store. Losing that store is not
197  * a problem either because that will result in one extra go around the loop
198  * and our @cond test will save the day.
199  *
200  * Also see the comments of try_to_wake_up().
201  */
202 #define __set_current_state(state_value)				\
203 	do {								\
204 		debug_normal_state_change((state_value));		\
205 		WRITE_ONCE(current->__state, (state_value));		\
206 	} while (0)
207 
208 #define set_current_state(state_value)					\
209 	do {								\
210 		debug_normal_state_change((state_value));		\
211 		smp_store_mb(current->__state, (state_value));		\
212 	} while (0)
213 
214 /*
215  * set_special_state() should be used for those states when the blocking task
216  * can not use the regular condition based wait-loop. In that case we must
217  * serialize against wakeups such that any possible in-flight TASK_RUNNING
218  * stores will not collide with our state change.
219  */
220 #define set_special_state(state_value)					\
221 	do {								\
222 		unsigned long flags; /* may shadow */			\
223 									\
224 		raw_spin_lock_irqsave(&current->pi_lock, flags);	\
225 		debug_special_state_change((state_value));		\
226 		WRITE_ONCE(current->__state, (state_value));		\
227 		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	\
228 	} while (0)
229 
230 /*
231  * PREEMPT_RT specific variants for "sleeping" spin/rwlocks
232  *
233  * RT's spin/rwlock substitutions are state preserving. The state of the
234  * task when blocking on the lock is saved in task_struct::saved_state and
235  * restored after the lock has been acquired.  These operations are
236  * serialized by task_struct::pi_lock against try_to_wake_up(). Any non RT
237  * lock related wakeups while the task is blocked on the lock are
238  * redirected to operate on task_struct::saved_state to ensure that these
239  * are not dropped. On restore task_struct::saved_state is set to
240  * TASK_RUNNING so any wakeup attempt redirected to saved_state will fail.
241  *
242  * The lock operation looks like this:
243  *
244  *	current_save_and_set_rtlock_wait_state();
245  *	for (;;) {
246  *		if (try_lock())
247  *			break;
248  *		raw_spin_unlock_irq(&lock->wait_lock);
249  *		schedule_rtlock();
250  *		raw_spin_lock_irq(&lock->wait_lock);
251  *		set_current_state(TASK_RTLOCK_WAIT);
252  *	}
253  *	current_restore_rtlock_saved_state();
254  */
255 #define current_save_and_set_rtlock_wait_state()			\
256 	do {								\
257 		lockdep_assert_irqs_disabled();				\
258 		raw_spin_lock(&current->pi_lock);			\
259 		current->saved_state = current->__state;		\
260 		debug_rtlock_wait_set_state();				\
261 		WRITE_ONCE(current->__state, TASK_RTLOCK_WAIT);		\
262 		raw_spin_unlock(&current->pi_lock);			\
263 	} while (0);
264 
265 #define current_restore_rtlock_saved_state()				\
266 	do {								\
267 		lockdep_assert_irqs_disabled();				\
268 		raw_spin_lock(&current->pi_lock);			\
269 		debug_rtlock_wait_restore_state();			\
270 		WRITE_ONCE(current->__state, current->saved_state);	\
271 		current->saved_state = TASK_RUNNING;			\
272 		raw_spin_unlock(&current->pi_lock);			\
273 	} while (0);
274 
275 #define get_current_state()	READ_ONCE(current->__state)
276 
277 /* Task command name length: */
278 #define TASK_COMM_LEN			16
279 
280 extern void scheduler_tick(void);
281 
282 #define	MAX_SCHEDULE_TIMEOUT		LONG_MAX
283 
284 extern long schedule_timeout(long timeout);
285 extern long schedule_timeout_interruptible(long timeout);
286 extern long schedule_timeout_killable(long timeout);
287 extern long schedule_timeout_uninterruptible(long timeout);
288 extern long schedule_timeout_idle(long timeout);
289 asmlinkage void schedule(void);
290 extern void schedule_preempt_disabled(void);
291 asmlinkage void preempt_schedule_irq(void);
292 #ifdef CONFIG_PREEMPT_RT
293  extern void schedule_rtlock(void);
294 #endif
295 
296 extern int __must_check io_schedule_prepare(void);
297 extern void io_schedule_finish(int token);
298 extern long io_schedule_timeout(long timeout);
299 extern void io_schedule(void);
300 
301 /**
302  * struct prev_cputime - snapshot of system and user cputime
303  * @utime: time spent in user mode
304  * @stime: time spent in system mode
305  * @lock: protects the above two fields
306  *
307  * Stores previous user/system time values such that we can guarantee
308  * monotonicity.
309  */
310 struct prev_cputime {
311 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
312 	u64				utime;
313 	u64				stime;
314 	raw_spinlock_t			lock;
315 #endif
316 };
317 
318 enum vtime_state {
319 	/* Task is sleeping or running in a CPU with VTIME inactive: */
320 	VTIME_INACTIVE = 0,
321 	/* Task is idle */
322 	VTIME_IDLE,
323 	/* Task runs in kernelspace in a CPU with VTIME active: */
324 	VTIME_SYS,
325 	/* Task runs in userspace in a CPU with VTIME active: */
326 	VTIME_USER,
327 	/* Task runs as guests in a CPU with VTIME active: */
328 	VTIME_GUEST,
329 };
330 
331 struct vtime {
332 	seqcount_t		seqcount;
333 	unsigned long long	starttime;
334 	enum vtime_state	state;
335 	unsigned int		cpu;
336 	u64			utime;
337 	u64			stime;
338 	u64			gtime;
339 };
340 
341 /*
342  * Utilization clamp constraints.
343  * @UCLAMP_MIN:	Minimum utilization
344  * @UCLAMP_MAX:	Maximum utilization
345  * @UCLAMP_CNT:	Utilization clamp constraints count
346  */
347 enum uclamp_id {
348 	UCLAMP_MIN = 0,
349 	UCLAMP_MAX,
350 	UCLAMP_CNT
351 };
352 
353 #ifdef CONFIG_SMP
354 extern struct root_domain def_root_domain;
355 extern struct mutex sched_domains_mutex;
356 #endif
357 
358 struct sched_info {
359 #ifdef CONFIG_SCHED_INFO
360 	/* Cumulative counters: */
361 
362 	/* # of times we have run on this CPU: */
363 	unsigned long			pcount;
364 
365 	/* Time spent waiting on a runqueue: */
366 	unsigned long long		run_delay;
367 
368 	/* Timestamps: */
369 
370 	/* When did we last run on a CPU? */
371 	unsigned long long		last_arrival;
372 
373 	/* When were we last queued to run? */
374 	unsigned long long		last_queued;
375 
376 #endif /* CONFIG_SCHED_INFO */
377 };
378 
379 /*
380  * Integer metrics need fixed point arithmetic, e.g., sched/fair
381  * has a few: load, load_avg, util_avg, freq, and capacity.
382  *
383  * We define a basic fixed point arithmetic range, and then formalize
384  * all these metrics based on that basic range.
385  */
386 # define SCHED_FIXEDPOINT_SHIFT		10
387 # define SCHED_FIXEDPOINT_SCALE		(1L << SCHED_FIXEDPOINT_SHIFT)
388 
389 /* Increase resolution of cpu_capacity calculations */
390 # define SCHED_CAPACITY_SHIFT		SCHED_FIXEDPOINT_SHIFT
391 # define SCHED_CAPACITY_SCALE		(1L << SCHED_CAPACITY_SHIFT)
392 
393 struct load_weight {
394 	unsigned long			weight;
395 	u32				inv_weight;
396 };
397 
398 /**
399  * struct util_est - Estimation utilization of FAIR tasks
400  * @enqueued: instantaneous estimated utilization of a task/cpu
401  * @ewma:     the Exponential Weighted Moving Average (EWMA)
402  *            utilization of a task
403  *
404  * Support data structure to track an Exponential Weighted Moving Average
405  * (EWMA) of a FAIR task's utilization. New samples are added to the moving
406  * average each time a task completes an activation. Sample's weight is chosen
407  * so that the EWMA will be relatively insensitive to transient changes to the
408  * task's workload.
409  *
410  * The enqueued attribute has a slightly different meaning for tasks and cpus:
411  * - task:   the task's util_avg at last task dequeue time
412  * - cfs_rq: the sum of util_est.enqueued for each RUNNABLE task on that CPU
413  * Thus, the util_est.enqueued of a task represents the contribution on the
414  * estimated utilization of the CPU where that task is currently enqueued.
415  *
416  * Only for tasks we track a moving average of the past instantaneous
417  * estimated utilization. This allows to absorb sporadic drops in utilization
418  * of an otherwise almost periodic task.
419  *
420  * The UTIL_AVG_UNCHANGED flag is used to synchronize util_est with util_avg
421  * updates. When a task is dequeued, its util_est should not be updated if its
422  * util_avg has not been updated in the meantime.
423  * This information is mapped into the MSB bit of util_est.enqueued at dequeue
424  * time. Since max value of util_est.enqueued for a task is 1024 (PELT util_avg
425  * for a task) it is safe to use MSB.
426  */
427 struct util_est {
428 	unsigned int			enqueued;
429 	unsigned int			ewma;
430 #define UTIL_EST_WEIGHT_SHIFT		2
431 #define UTIL_AVG_UNCHANGED		0x80000000
432 } __attribute__((__aligned__(sizeof(u64))));
433 
434 /*
435  * The load/runnable/util_avg accumulates an infinite geometric series
436  * (see __update_load_avg_cfs_rq() in kernel/sched/pelt.c).
437  *
438  * [load_avg definition]
439  *
440  *   load_avg = runnable% * scale_load_down(load)
441  *
442  * [runnable_avg definition]
443  *
444  *   runnable_avg = runnable% * SCHED_CAPACITY_SCALE
445  *
446  * [util_avg definition]
447  *
448  *   util_avg = running% * SCHED_CAPACITY_SCALE
449  *
450  * where runnable% is the time ratio that a sched_entity is runnable and
451  * running% the time ratio that a sched_entity is running.
452  *
453  * For cfs_rq, they are the aggregated values of all runnable and blocked
454  * sched_entities.
455  *
456  * The load/runnable/util_avg doesn't directly factor frequency scaling and CPU
457  * capacity scaling. The scaling is done through the rq_clock_pelt that is used
458  * for computing those signals (see update_rq_clock_pelt())
459  *
460  * N.B., the above ratios (runnable% and running%) themselves are in the
461  * range of [0, 1]. To do fixed point arithmetics, we therefore scale them
462  * to as large a range as necessary. This is for example reflected by
463  * util_avg's SCHED_CAPACITY_SCALE.
464  *
465  * [Overflow issue]
466  *
467  * The 64-bit load_sum can have 4353082796 (=2^64/47742/88761) entities
468  * with the highest load (=88761), always runnable on a single cfs_rq,
469  * and should not overflow as the number already hits PID_MAX_LIMIT.
470  *
471  * For all other cases (including 32-bit kernels), struct load_weight's
472  * weight will overflow first before we do, because:
473  *
474  *    Max(load_avg) <= Max(load.weight)
475  *
476  * Then it is the load_weight's responsibility to consider overflow
477  * issues.
478  */
479 struct sched_avg {
480 	u64				last_update_time;
481 	u64				load_sum;
482 	u64				runnable_sum;
483 	u32				util_sum;
484 	u32				period_contrib;
485 	unsigned long			load_avg;
486 	unsigned long			runnable_avg;
487 	unsigned long			util_avg;
488 	struct util_est			util_est;
489 } ____cacheline_aligned;
490 
491 struct sched_statistics {
492 #ifdef CONFIG_SCHEDSTATS
493 	u64				wait_start;
494 	u64				wait_max;
495 	u64				wait_count;
496 	u64				wait_sum;
497 	u64				iowait_count;
498 	u64				iowait_sum;
499 
500 	u64				sleep_start;
501 	u64				sleep_max;
502 	s64				sum_sleep_runtime;
503 
504 	u64				block_start;
505 	u64				block_max;
506 	s64				sum_block_runtime;
507 
508 	u64				exec_max;
509 	u64				slice_max;
510 
511 	u64				nr_migrations_cold;
512 	u64				nr_failed_migrations_affine;
513 	u64				nr_failed_migrations_running;
514 	u64				nr_failed_migrations_hot;
515 	u64				nr_forced_migrations;
516 
517 	u64				nr_wakeups;
518 	u64				nr_wakeups_sync;
519 	u64				nr_wakeups_migrate;
520 	u64				nr_wakeups_local;
521 	u64				nr_wakeups_remote;
522 	u64				nr_wakeups_affine;
523 	u64				nr_wakeups_affine_attempts;
524 	u64				nr_wakeups_passive;
525 	u64				nr_wakeups_idle;
526 #endif
527 } ____cacheline_aligned;
528 
529 struct sched_entity {
530 	/* For load-balancing: */
531 	struct load_weight		load;
532 	struct rb_node			run_node;
533 	struct list_head		group_node;
534 	unsigned int			on_rq;
535 
536 	u64				exec_start;
537 	u64				sum_exec_runtime;
538 	u64				vruntime;
539 	u64				prev_sum_exec_runtime;
540 
541 	u64				nr_migrations;
542 
543 #ifdef CONFIG_FAIR_GROUP_SCHED
544 	int				depth;
545 	struct sched_entity		*parent;
546 	/* rq on which this entity is (to be) queued: */
547 	struct cfs_rq			*cfs_rq;
548 	/* rq "owned" by this entity/group: */
549 	struct cfs_rq			*my_q;
550 	/* cached value of my_q->h_nr_running */
551 	unsigned long			runnable_weight;
552 #endif
553 
554 #ifdef CONFIG_SMP
555 	/*
556 	 * Per entity load average tracking.
557 	 *
558 	 * Put into separate cache line so it does not
559 	 * collide with read-mostly values above.
560 	 */
561 	struct sched_avg		avg;
562 #endif
563 };
564 
565 struct sched_rt_entity {
566 	struct list_head		run_list;
567 	unsigned long			timeout;
568 	unsigned long			watchdog_stamp;
569 	unsigned int			time_slice;
570 	unsigned short			on_rq;
571 	unsigned short			on_list;
572 
573 	struct sched_rt_entity		*back;
574 #ifdef CONFIG_RT_GROUP_SCHED
575 	struct sched_rt_entity		*parent;
576 	/* rq on which this entity is (to be) queued: */
577 	struct rt_rq			*rt_rq;
578 	/* rq "owned" by this entity/group: */
579 	struct rt_rq			*my_q;
580 #endif
581 } __randomize_layout;
582 
583 struct sched_dl_entity {
584 	struct rb_node			rb_node;
585 
586 	/*
587 	 * Original scheduling parameters. Copied here from sched_attr
588 	 * during sched_setattr(), they will remain the same until
589 	 * the next sched_setattr().
590 	 */
591 	u64				dl_runtime;	/* Maximum runtime for each instance	*/
592 	u64				dl_deadline;	/* Relative deadline of each instance	*/
593 	u64				dl_period;	/* Separation of two instances (period) */
594 	u64				dl_bw;		/* dl_runtime / dl_period		*/
595 	u64				dl_density;	/* dl_runtime / dl_deadline		*/
596 
597 	/*
598 	 * Actual scheduling parameters. Initialized with the values above,
599 	 * they are continuously updated during task execution. Note that
600 	 * the remaining runtime could be < 0 in case we are in overrun.
601 	 */
602 	s64				runtime;	/* Remaining runtime for this instance	*/
603 	u64				deadline;	/* Absolute deadline for this instance	*/
604 	unsigned int			flags;		/* Specifying the scheduler behaviour	*/
605 
606 	/*
607 	 * Some bool flags:
608 	 *
609 	 * @dl_throttled tells if we exhausted the runtime. If so, the
610 	 * task has to wait for a replenishment to be performed at the
611 	 * next firing of dl_timer.
612 	 *
613 	 * @dl_boosted tells if we are boosted due to DI. If so we are
614 	 * outside bandwidth enforcement mechanism (but only until we
615 	 * exit the critical section);
616 	 *
617 	 * @dl_yielded tells if task gave up the CPU before consuming
618 	 * all its available runtime during the last job.
619 	 *
620 	 * @dl_non_contending tells if the task is inactive while still
621 	 * contributing to the active utilization. In other words, it
622 	 * indicates if the inactive timer has been armed and its handler
623 	 * has not been executed yet. This flag is useful to avoid race
624 	 * conditions between the inactive timer handler and the wakeup
625 	 * code.
626 	 *
627 	 * @dl_overrun tells if the task asked to be informed about runtime
628 	 * overruns.
629 	 */
630 	unsigned int			dl_throttled      : 1;
631 	unsigned int			dl_yielded        : 1;
632 	unsigned int			dl_non_contending : 1;
633 	unsigned int			dl_overrun	  : 1;
634 
635 	/*
636 	 * Bandwidth enforcement timer. Each -deadline task has its
637 	 * own bandwidth to be enforced, thus we need one timer per task.
638 	 */
639 	struct hrtimer			dl_timer;
640 
641 	/*
642 	 * Inactive timer, responsible for decreasing the active utilization
643 	 * at the "0-lag time". When a -deadline task blocks, it contributes
644 	 * to GRUB's active utilization until the "0-lag time", hence a
645 	 * timer is needed to decrease the active utilization at the correct
646 	 * time.
647 	 */
648 	struct hrtimer inactive_timer;
649 
650 #ifdef CONFIG_RT_MUTEXES
651 	/*
652 	 * Priority Inheritance. When a DEADLINE scheduling entity is boosted
653 	 * pi_se points to the donor, otherwise points to the dl_se it belongs
654 	 * to (the original one/itself).
655 	 */
656 	struct sched_dl_entity *pi_se;
657 #endif
658 };
659 
660 #ifdef CONFIG_UCLAMP_TASK
661 /* Number of utilization clamp buckets (shorter alias) */
662 #define UCLAMP_BUCKETS CONFIG_UCLAMP_BUCKETS_COUNT
663 
664 /*
665  * Utilization clamp for a scheduling entity
666  * @value:		clamp value "assigned" to a se
667  * @bucket_id:		bucket index corresponding to the "assigned" value
668  * @active:		the se is currently refcounted in a rq's bucket
669  * @user_defined:	the requested clamp value comes from user-space
670  *
671  * The bucket_id is the index of the clamp bucket matching the clamp value
672  * which is pre-computed and stored to avoid expensive integer divisions from
673  * the fast path.
674  *
675  * The active bit is set whenever a task has got an "effective" value assigned,
676  * which can be different from the clamp value "requested" from user-space.
677  * This allows to know a task is refcounted in the rq's bucket corresponding
678  * to the "effective" bucket_id.
679  *
680  * The user_defined bit is set whenever a task has got a task-specific clamp
681  * value requested from userspace, i.e. the system defaults apply to this task
682  * just as a restriction. This allows to relax default clamps when a less
683  * restrictive task-specific value has been requested, thus allowing to
684  * implement a "nice" semantic. For example, a task running with a 20%
685  * default boost can still drop its own boosting to 0%.
686  */
687 struct uclamp_se {
688 	unsigned int value		: bits_per(SCHED_CAPACITY_SCALE);
689 	unsigned int bucket_id		: bits_per(UCLAMP_BUCKETS);
690 	unsigned int active		: 1;
691 	unsigned int user_defined	: 1;
692 };
693 #endif /* CONFIG_UCLAMP_TASK */
694 
695 union rcu_special {
696 	struct {
697 		u8			blocked;
698 		u8			need_qs;
699 		u8			exp_hint; /* Hint for performance. */
700 		u8			need_mb; /* Readers need smp_mb(). */
701 	} b; /* Bits. */
702 	u32 s; /* Set of bits. */
703 };
704 
705 enum perf_event_task_context {
706 	perf_invalid_context = -1,
707 	perf_hw_context = 0,
708 	perf_sw_context,
709 	perf_nr_task_contexts,
710 };
711 
712 struct wake_q_node {
713 	struct wake_q_node *next;
714 };
715 
716 struct kmap_ctrl {
717 #ifdef CONFIG_KMAP_LOCAL
718 	int				idx;
719 	pte_t				pteval[KM_MAX_IDX];
720 #endif
721 };
722 
723 struct task_struct {
724 #ifdef CONFIG_THREAD_INFO_IN_TASK
725 	/*
726 	 * For reasons of header soup (see current_thread_info()), this
727 	 * must be the first element of task_struct.
728 	 */
729 	struct thread_info		thread_info;
730 #endif
731 	unsigned int			__state;
732 
733 #ifdef CONFIG_PREEMPT_RT
734 	/* saved state for "spinlock sleepers" */
735 	unsigned int			saved_state;
736 #endif
737 
738 	/*
739 	 * This begins the randomizable portion of task_struct. Only
740 	 * scheduling-critical items should be added above here.
741 	 */
742 	randomized_struct_fields_start
743 
744 	void				*stack;
745 	refcount_t			usage;
746 	/* Per task flags (PF_*), defined further below: */
747 	unsigned int			flags;
748 	unsigned int			ptrace;
749 
750 #ifdef CONFIG_SMP
751 	int				on_cpu;
752 	struct __call_single_node	wake_entry;
753 	unsigned int			wakee_flips;
754 	unsigned long			wakee_flip_decay_ts;
755 	struct task_struct		*last_wakee;
756 
757 	/*
758 	 * recent_used_cpu is initially set as the last CPU used by a task
759 	 * that wakes affine another task. Waker/wakee relationships can
760 	 * push tasks around a CPU where each wakeup moves to the next one.
761 	 * Tracking a recently used CPU allows a quick search for a recently
762 	 * used CPU that may be idle.
763 	 */
764 	int				recent_used_cpu;
765 	int				wake_cpu;
766 #endif
767 	int				on_rq;
768 
769 	int				prio;
770 	int				static_prio;
771 	int				normal_prio;
772 	unsigned int			rt_priority;
773 
774 	struct sched_entity		se;
775 	struct sched_rt_entity		rt;
776 	struct sched_dl_entity		dl;
777 	const struct sched_class	*sched_class;
778 
779 #ifdef CONFIG_SCHED_CORE
780 	struct rb_node			core_node;
781 	unsigned long			core_cookie;
782 	unsigned int			core_occupation;
783 #endif
784 
785 #ifdef CONFIG_CGROUP_SCHED
786 	struct task_group		*sched_task_group;
787 #endif
788 
789 #ifdef CONFIG_UCLAMP_TASK
790 	/*
791 	 * Clamp values requested for a scheduling entity.
792 	 * Must be updated with task_rq_lock() held.
793 	 */
794 	struct uclamp_se		uclamp_req[UCLAMP_CNT];
795 	/*
796 	 * Effective clamp values used for a scheduling entity.
797 	 * Must be updated with task_rq_lock() held.
798 	 */
799 	struct uclamp_se		uclamp[UCLAMP_CNT];
800 #endif
801 
802 	struct sched_statistics         stats;
803 
804 #ifdef CONFIG_PREEMPT_NOTIFIERS
805 	/* List of struct preempt_notifier: */
806 	struct hlist_head		preempt_notifiers;
807 #endif
808 
809 #ifdef CONFIG_BLK_DEV_IO_TRACE
810 	unsigned int			btrace_seq;
811 #endif
812 
813 	unsigned int			policy;
814 	int				nr_cpus_allowed;
815 	const cpumask_t			*cpus_ptr;
816 	cpumask_t			*user_cpus_ptr;
817 	cpumask_t			cpus_mask;
818 	void				*migration_pending;
819 #ifdef CONFIG_SMP
820 	unsigned short			migration_disabled;
821 #endif
822 	unsigned short			migration_flags;
823 
824 #ifdef CONFIG_PREEMPT_RCU
825 	int				rcu_read_lock_nesting;
826 	union rcu_special		rcu_read_unlock_special;
827 	struct list_head		rcu_node_entry;
828 	struct rcu_node			*rcu_blocked_node;
829 #endif /* #ifdef CONFIG_PREEMPT_RCU */
830 
831 #ifdef CONFIG_TASKS_RCU
832 	unsigned long			rcu_tasks_nvcsw;
833 	u8				rcu_tasks_holdout;
834 	u8				rcu_tasks_idx;
835 	int				rcu_tasks_idle_cpu;
836 	struct list_head		rcu_tasks_holdout_list;
837 #endif /* #ifdef CONFIG_TASKS_RCU */
838 
839 #ifdef CONFIG_TASKS_TRACE_RCU
840 	int				trc_reader_nesting;
841 	int				trc_ipi_to_cpu;
842 	union rcu_special		trc_reader_special;
843 	bool				trc_reader_checked;
844 	struct list_head		trc_holdout_list;
845 #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
846 
847 	struct sched_info		sched_info;
848 
849 	struct list_head		tasks;
850 #ifdef CONFIG_SMP
851 	struct plist_node		pushable_tasks;
852 	struct rb_node			pushable_dl_tasks;
853 #endif
854 
855 	struct mm_struct		*mm;
856 	struct mm_struct		*active_mm;
857 
858 	/* Per-thread vma caching: */
859 	struct vmacache			vmacache;
860 
861 #ifdef SPLIT_RSS_COUNTING
862 	struct task_rss_stat		rss_stat;
863 #endif
864 	int				exit_state;
865 	int				exit_code;
866 	int				exit_signal;
867 	/* The signal sent when the parent dies: */
868 	int				pdeath_signal;
869 	/* JOBCTL_*, siglock protected: */
870 	unsigned long			jobctl;
871 
872 	/* Used for emulating ABI behavior of previous Linux versions: */
873 	unsigned int			personality;
874 
875 	/* Scheduler bits, serialized by scheduler locks: */
876 	unsigned			sched_reset_on_fork:1;
877 	unsigned			sched_contributes_to_load:1;
878 	unsigned			sched_migrated:1;
879 #ifdef CONFIG_PSI
880 	unsigned			sched_psi_wake_requeue:1;
881 #endif
882 
883 	/* Force alignment to the next boundary: */
884 	unsigned			:0;
885 
886 	/* Unserialized, strictly 'current' */
887 
888 	/*
889 	 * This field must not be in the scheduler word above due to wakelist
890 	 * queueing no longer being serialized by p->on_cpu. However:
891 	 *
892 	 * p->XXX = X;			ttwu()
893 	 * schedule()			  if (p->on_rq && ..) // false
894 	 *   smp_mb__after_spinlock();	  if (smp_load_acquire(&p->on_cpu) && //true
895 	 *   deactivate_task()		      ttwu_queue_wakelist())
896 	 *     p->on_rq = 0;			p->sched_remote_wakeup = Y;
897 	 *
898 	 * guarantees all stores of 'current' are visible before
899 	 * ->sched_remote_wakeup gets used, so it can be in this word.
900 	 */
901 	unsigned			sched_remote_wakeup:1;
902 
903 	/* Bit to tell LSMs we're in execve(): */
904 	unsigned			in_execve:1;
905 	unsigned			in_iowait:1;
906 #ifndef TIF_RESTORE_SIGMASK
907 	unsigned			restore_sigmask:1;
908 #endif
909 #ifdef CONFIG_MEMCG
910 	unsigned			in_user_fault:1;
911 #endif
912 #ifdef CONFIG_COMPAT_BRK
913 	unsigned			brk_randomized:1;
914 #endif
915 #ifdef CONFIG_CGROUPS
916 	/* disallow userland-initiated cgroup migration */
917 	unsigned			no_cgroup_migration:1;
918 	/* task is frozen/stopped (used by the cgroup freezer) */
919 	unsigned			frozen:1;
920 #endif
921 #ifdef CONFIG_BLK_CGROUP
922 	unsigned			use_memdelay:1;
923 #endif
924 #ifdef CONFIG_PSI
925 	/* Stalled due to lack of memory */
926 	unsigned			in_memstall:1;
927 #endif
928 #ifdef CONFIG_PAGE_OWNER
929 	/* Used by page_owner=on to detect recursion in page tracking. */
930 	unsigned			in_page_owner:1;
931 #endif
932 #ifdef CONFIG_EVENTFD
933 	/* Recursion prevention for eventfd_signal() */
934 	unsigned			in_eventfd_signal:1;
935 #endif
936 
937 	unsigned long			atomic_flags; /* Flags requiring atomic access. */
938 
939 	struct restart_block		restart_block;
940 
941 	pid_t				pid;
942 	pid_t				tgid;
943 
944 #ifdef CONFIG_STACKPROTECTOR
945 	/* Canary value for the -fstack-protector GCC feature: */
946 	unsigned long			stack_canary;
947 #endif
948 	/*
949 	 * Pointers to the (original) parent process, youngest child, younger sibling,
950 	 * older sibling, respectively.  (p->father can be replaced with
951 	 * p->real_parent->pid)
952 	 */
953 
954 	/* Real parent process: */
955 	struct task_struct __rcu	*real_parent;
956 
957 	/* Recipient of SIGCHLD, wait4() reports: */
958 	struct task_struct __rcu	*parent;
959 
960 	/*
961 	 * Children/sibling form the list of natural children:
962 	 */
963 	struct list_head		children;
964 	struct list_head		sibling;
965 	struct task_struct		*group_leader;
966 
967 	/*
968 	 * 'ptraced' is the list of tasks this task is using ptrace() on.
969 	 *
970 	 * This includes both natural children and PTRACE_ATTACH targets.
971 	 * 'ptrace_entry' is this task's link on the p->parent->ptraced list.
972 	 */
973 	struct list_head		ptraced;
974 	struct list_head		ptrace_entry;
975 
976 	/* PID/PID hash table linkage. */
977 	struct pid			*thread_pid;
978 	struct hlist_node		pid_links[PIDTYPE_MAX];
979 	struct list_head		thread_group;
980 	struct list_head		thread_node;
981 
982 	struct completion		*vfork_done;
983 
984 	/* CLONE_CHILD_SETTID: */
985 	int __user			*set_child_tid;
986 
987 	/* CLONE_CHILD_CLEARTID: */
988 	int __user			*clear_child_tid;
989 
990 	/* PF_IO_WORKER */
991 	void				*pf_io_worker;
992 
993 	u64				utime;
994 	u64				stime;
995 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
996 	u64				utimescaled;
997 	u64				stimescaled;
998 #endif
999 	u64				gtime;
1000 	struct prev_cputime		prev_cputime;
1001 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1002 	struct vtime			vtime;
1003 #endif
1004 
1005 #ifdef CONFIG_NO_HZ_FULL
1006 	atomic_t			tick_dep_mask;
1007 #endif
1008 	/* Context switch counts: */
1009 	unsigned long			nvcsw;
1010 	unsigned long			nivcsw;
1011 
1012 	/* Monotonic time in nsecs: */
1013 	u64				start_time;
1014 
1015 	/* Boot based time in nsecs: */
1016 	u64				start_boottime;
1017 
1018 	/* MM fault and swap info: this can arguably be seen as either mm-specific or thread-specific: */
1019 	unsigned long			min_flt;
1020 	unsigned long			maj_flt;
1021 
1022 	/* Empty if CONFIG_POSIX_CPUTIMERS=n */
1023 	struct posix_cputimers		posix_cputimers;
1024 
1025 #ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
1026 	struct posix_cputimers_work	posix_cputimers_work;
1027 #endif
1028 
1029 	/* Process credentials: */
1030 
1031 	/* Tracer's credentials at attach: */
1032 	const struct cred __rcu		*ptracer_cred;
1033 
1034 	/* Objective and real subjective task credentials (COW): */
1035 	const struct cred __rcu		*real_cred;
1036 
1037 	/* Effective (overridable) subjective task credentials (COW): */
1038 	const struct cred __rcu		*cred;
1039 
1040 #ifdef CONFIG_KEYS
1041 	/* Cached requested key. */
1042 	struct key			*cached_requested_key;
1043 #endif
1044 
1045 	/*
1046 	 * executable name, excluding path.
1047 	 *
1048 	 * - normally initialized setup_new_exec()
1049 	 * - access it with [gs]et_task_comm()
1050 	 * - lock it with task_lock()
1051 	 */
1052 	char				comm[TASK_COMM_LEN];
1053 
1054 	struct nameidata		*nameidata;
1055 
1056 #ifdef CONFIG_SYSVIPC
1057 	struct sysv_sem			sysvsem;
1058 	struct sysv_shm			sysvshm;
1059 #endif
1060 #ifdef CONFIG_DETECT_HUNG_TASK
1061 	unsigned long			last_switch_count;
1062 	unsigned long			last_switch_time;
1063 #endif
1064 	/* Filesystem information: */
1065 	struct fs_struct		*fs;
1066 
1067 	/* Open file information: */
1068 	struct files_struct		*files;
1069 
1070 #ifdef CONFIG_IO_URING
1071 	struct io_uring_task		*io_uring;
1072 #endif
1073 
1074 	/* Namespaces: */
1075 	struct nsproxy			*nsproxy;
1076 
1077 	/* Signal handlers: */
1078 	struct signal_struct		*signal;
1079 	struct sighand_struct __rcu		*sighand;
1080 	sigset_t			blocked;
1081 	sigset_t			real_blocked;
1082 	/* Restored if set_restore_sigmask() was used: */
1083 	sigset_t			saved_sigmask;
1084 	struct sigpending		pending;
1085 	unsigned long			sas_ss_sp;
1086 	size_t				sas_ss_size;
1087 	unsigned int			sas_ss_flags;
1088 
1089 	struct callback_head		*task_works;
1090 
1091 #ifdef CONFIG_AUDIT
1092 #ifdef CONFIG_AUDITSYSCALL
1093 	struct audit_context		*audit_context;
1094 #endif
1095 	kuid_t				loginuid;
1096 	unsigned int			sessionid;
1097 #endif
1098 	struct seccomp			seccomp;
1099 	struct syscall_user_dispatch	syscall_dispatch;
1100 
1101 	/* Thread group tracking: */
1102 	u64				parent_exec_id;
1103 	u64				self_exec_id;
1104 
1105 	/* Protection against (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed, mempolicy: */
1106 	spinlock_t			alloc_lock;
1107 
1108 	/* Protection of the PI data structures: */
1109 	raw_spinlock_t			pi_lock;
1110 
1111 	struct wake_q_node		wake_q;
1112 
1113 #ifdef CONFIG_RT_MUTEXES
1114 	/* PI waiters blocked on a rt_mutex held by this task: */
1115 	struct rb_root_cached		pi_waiters;
1116 	/* Updated under owner's pi_lock and rq lock */
1117 	struct task_struct		*pi_top_task;
1118 	/* Deadlock detection and priority inheritance handling: */
1119 	struct rt_mutex_waiter		*pi_blocked_on;
1120 #endif
1121 
1122 #ifdef CONFIG_DEBUG_MUTEXES
1123 	/* Mutex deadlock detection: */
1124 	struct mutex_waiter		*blocked_on;
1125 #endif
1126 
1127 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1128 	int				non_block_count;
1129 #endif
1130 
1131 #ifdef CONFIG_TRACE_IRQFLAGS
1132 	struct irqtrace_events		irqtrace;
1133 	unsigned int			hardirq_threaded;
1134 	u64				hardirq_chain_key;
1135 	int				softirqs_enabled;
1136 	int				softirq_context;
1137 	int				irq_config;
1138 #endif
1139 #ifdef CONFIG_PREEMPT_RT
1140 	int				softirq_disable_cnt;
1141 #endif
1142 
1143 #ifdef CONFIG_LOCKDEP
1144 # define MAX_LOCK_DEPTH			48UL
1145 	u64				curr_chain_key;
1146 	int				lockdep_depth;
1147 	unsigned int			lockdep_recursion;
1148 	struct held_lock		held_locks[MAX_LOCK_DEPTH];
1149 #endif
1150 
1151 #if defined(CONFIG_UBSAN) && !defined(CONFIG_UBSAN_TRAP)
1152 	unsigned int			in_ubsan;
1153 #endif
1154 
1155 	/* Journalling filesystem info: */
1156 	void				*journal_info;
1157 
1158 	/* Stacked block device info: */
1159 	struct bio_list			*bio_list;
1160 
1161 	/* Stack plugging: */
1162 	struct blk_plug			*plug;
1163 
1164 	/* VM state: */
1165 	struct reclaim_state		*reclaim_state;
1166 
1167 	struct backing_dev_info		*backing_dev_info;
1168 
1169 	struct io_context		*io_context;
1170 
1171 #ifdef CONFIG_COMPACTION
1172 	struct capture_control		*capture_control;
1173 #endif
1174 	/* Ptrace state: */
1175 	unsigned long			ptrace_message;
1176 	kernel_siginfo_t		*last_siginfo;
1177 
1178 	struct task_io_accounting	ioac;
1179 #ifdef CONFIG_PSI
1180 	/* Pressure stall state */
1181 	unsigned int			psi_flags;
1182 #endif
1183 #ifdef CONFIG_TASK_XACCT
1184 	/* Accumulated RSS usage: */
1185 	u64				acct_rss_mem1;
1186 	/* Accumulated virtual memory usage: */
1187 	u64				acct_vm_mem1;
1188 	/* stime + utime since last update: */
1189 	u64				acct_timexpd;
1190 #endif
1191 #ifdef CONFIG_CPUSETS
1192 	/* Protected by ->alloc_lock: */
1193 	nodemask_t			mems_allowed;
1194 	/* Sequence number to catch updates: */
1195 	seqcount_spinlock_t		mems_allowed_seq;
1196 	int				cpuset_mem_spread_rotor;
1197 	int				cpuset_slab_spread_rotor;
1198 #endif
1199 #ifdef CONFIG_CGROUPS
1200 	/* Control Group info protected by css_set_lock: */
1201 	struct css_set __rcu		*cgroups;
1202 	/* cg_list protected by css_set_lock and tsk->alloc_lock: */
1203 	struct list_head		cg_list;
1204 #endif
1205 #ifdef CONFIG_X86_CPU_RESCTRL
1206 	u32				closid;
1207 	u32				rmid;
1208 #endif
1209 #ifdef CONFIG_FUTEX
1210 	struct robust_list_head __user	*robust_list;
1211 #ifdef CONFIG_COMPAT
1212 	struct compat_robust_list_head __user *compat_robust_list;
1213 #endif
1214 	struct list_head		pi_state_list;
1215 	struct futex_pi_state		*pi_state_cache;
1216 	struct mutex			futex_exit_mutex;
1217 	unsigned int			futex_state;
1218 #endif
1219 #ifdef CONFIG_PERF_EVENTS
1220 	struct perf_event_context	*perf_event_ctxp[perf_nr_task_contexts];
1221 	struct mutex			perf_event_mutex;
1222 	struct list_head		perf_event_list;
1223 #endif
1224 #ifdef CONFIG_DEBUG_PREEMPT
1225 	unsigned long			preempt_disable_ip;
1226 #endif
1227 #ifdef CONFIG_NUMA
1228 	/* Protected by alloc_lock: */
1229 	struct mempolicy		*mempolicy;
1230 	short				il_prev;
1231 	short				pref_node_fork;
1232 #endif
1233 #ifdef CONFIG_NUMA_BALANCING
1234 	int				numa_scan_seq;
1235 	unsigned int			numa_scan_period;
1236 	unsigned int			numa_scan_period_max;
1237 	int				numa_preferred_nid;
1238 	unsigned long			numa_migrate_retry;
1239 	/* Migration stamp: */
1240 	u64				node_stamp;
1241 	u64				last_task_numa_placement;
1242 	u64				last_sum_exec_runtime;
1243 	struct callback_head		numa_work;
1244 
1245 	/*
1246 	 * This pointer is only modified for current in syscall and
1247 	 * pagefault context (and for tasks being destroyed), so it can be read
1248 	 * from any of the following contexts:
1249 	 *  - RCU read-side critical section
1250 	 *  - current->numa_group from everywhere
1251 	 *  - task's runqueue locked, task not running
1252 	 */
1253 	struct numa_group __rcu		*numa_group;
1254 
1255 	/*
1256 	 * numa_faults is an array split into four regions:
1257 	 * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
1258 	 * in this precise order.
1259 	 *
1260 	 * faults_memory: Exponential decaying average of faults on a per-node
1261 	 * basis. Scheduling placement decisions are made based on these
1262 	 * counts. The values remain static for the duration of a PTE scan.
1263 	 * faults_cpu: Track the nodes the process was running on when a NUMA
1264 	 * hinting fault was incurred.
1265 	 * faults_memory_buffer and faults_cpu_buffer: Record faults per node
1266 	 * during the current scan window. When the scan completes, the counts
1267 	 * in faults_memory and faults_cpu decay and these values are copied.
1268 	 */
1269 	unsigned long			*numa_faults;
1270 	unsigned long			total_numa_faults;
1271 
1272 	/*
1273 	 * numa_faults_locality tracks if faults recorded during the last
1274 	 * scan window were remote/local or failed to migrate. The task scan
1275 	 * period is adapted based on the locality of the faults with different
1276 	 * weights depending on whether they were shared or private faults
1277 	 */
1278 	unsigned long			numa_faults_locality[3];
1279 
1280 	unsigned long			numa_pages_migrated;
1281 #endif /* CONFIG_NUMA_BALANCING */
1282 
1283 #ifdef CONFIG_RSEQ
1284 	struct rseq __user *rseq;
1285 	u32 rseq_sig;
1286 	/*
1287 	 * RmW on rseq_event_mask must be performed atomically
1288 	 * with respect to preemption.
1289 	 */
1290 	unsigned long rseq_event_mask;
1291 #endif
1292 
1293 	struct tlbflush_unmap_batch	tlb_ubc;
1294 
1295 	union {
1296 		refcount_t		rcu_users;
1297 		struct rcu_head		rcu;
1298 	};
1299 
1300 	/* Cache last used pipe for splice(): */
1301 	struct pipe_inode_info		*splice_pipe;
1302 
1303 	struct page_frag		task_frag;
1304 
1305 #ifdef CONFIG_TASK_DELAY_ACCT
1306 	struct task_delay_info		*delays;
1307 #endif
1308 
1309 #ifdef CONFIG_FAULT_INJECTION
1310 	int				make_it_fail;
1311 	unsigned int			fail_nth;
1312 #endif
1313 	/*
1314 	 * When (nr_dirtied >= nr_dirtied_pause), it's time to call
1315 	 * balance_dirty_pages() for a dirty throttling pause:
1316 	 */
1317 	int				nr_dirtied;
1318 	int				nr_dirtied_pause;
1319 	/* Start of a write-and-pause period: */
1320 	unsigned long			dirty_paused_when;
1321 
1322 #ifdef CONFIG_LATENCYTOP
1323 	int				latency_record_count;
1324 	struct latency_record		latency_record[LT_SAVECOUNT];
1325 #endif
1326 	/*
1327 	 * Time slack values; these are used to round up poll() and
1328 	 * select() etc timeout values. These are in nanoseconds.
1329 	 */
1330 	u64				timer_slack_ns;
1331 	u64				default_timer_slack_ns;
1332 
1333 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
1334 	unsigned int			kasan_depth;
1335 #endif
1336 
1337 #ifdef CONFIG_KCSAN
1338 	struct kcsan_ctx		kcsan_ctx;
1339 #ifdef CONFIG_TRACE_IRQFLAGS
1340 	struct irqtrace_events		kcsan_save_irqtrace;
1341 #endif
1342 #endif
1343 
1344 #if IS_ENABLED(CONFIG_KUNIT)
1345 	struct kunit			*kunit_test;
1346 #endif
1347 
1348 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1349 	/* Index of current stored address in ret_stack: */
1350 	int				curr_ret_stack;
1351 	int				curr_ret_depth;
1352 
1353 	/* Stack of return addresses for return function tracing: */
1354 	struct ftrace_ret_stack		*ret_stack;
1355 
1356 	/* Timestamp for last schedule: */
1357 	unsigned long long		ftrace_timestamp;
1358 
1359 	/*
1360 	 * Number of functions that haven't been traced
1361 	 * because of depth overrun:
1362 	 */
1363 	atomic_t			trace_overrun;
1364 
1365 	/* Pause tracing: */
1366 	atomic_t			tracing_graph_pause;
1367 #endif
1368 
1369 #ifdef CONFIG_TRACING
1370 	/* State flags for use by tracers: */
1371 	unsigned long			trace;
1372 
1373 	/* Bitmask and counter of trace recursion: */
1374 	unsigned long			trace_recursion;
1375 #endif /* CONFIG_TRACING */
1376 
1377 #ifdef CONFIG_KCOV
1378 	/* See kernel/kcov.c for more details. */
1379 
1380 	/* Coverage collection mode enabled for this task (0 if disabled): */
1381 	unsigned int			kcov_mode;
1382 
1383 	/* Size of the kcov_area: */
1384 	unsigned int			kcov_size;
1385 
1386 	/* Buffer for coverage collection: */
1387 	void				*kcov_area;
1388 
1389 	/* KCOV descriptor wired with this task or NULL: */
1390 	struct kcov			*kcov;
1391 
1392 	/* KCOV common handle for remote coverage collection: */
1393 	u64				kcov_handle;
1394 
1395 	/* KCOV sequence number: */
1396 	int				kcov_sequence;
1397 
1398 	/* Collect coverage from softirq context: */
1399 	unsigned int			kcov_softirq;
1400 #endif
1401 
1402 #ifdef CONFIG_MEMCG
1403 	struct mem_cgroup		*memcg_in_oom;
1404 	gfp_t				memcg_oom_gfp_mask;
1405 	int				memcg_oom_order;
1406 
1407 	/* Number of pages to reclaim on returning to userland: */
1408 	unsigned int			memcg_nr_pages_over_high;
1409 
1410 	/* Used by memcontrol for targeted memcg charge: */
1411 	struct mem_cgroup		*active_memcg;
1412 #endif
1413 
1414 #ifdef CONFIG_BLK_CGROUP
1415 	struct request_queue		*throttle_queue;
1416 #endif
1417 
1418 #ifdef CONFIG_UPROBES
1419 	struct uprobe_task		*utask;
1420 #endif
1421 #if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
1422 	unsigned int			sequential_io;
1423 	unsigned int			sequential_io_avg;
1424 #endif
1425 	struct kmap_ctrl		kmap_ctrl;
1426 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1427 	unsigned long			task_state_change;
1428 # ifdef CONFIG_PREEMPT_RT
1429 	unsigned long			saved_state_change;
1430 # endif
1431 #endif
1432 	int				pagefault_disabled;
1433 #ifdef CONFIG_MMU
1434 	struct task_struct		*oom_reaper_list;
1435 #endif
1436 #ifdef CONFIG_VMAP_STACK
1437 	struct vm_struct		*stack_vm_area;
1438 #endif
1439 #ifdef CONFIG_THREAD_INFO_IN_TASK
1440 	/* A live task holds one reference: */
1441 	refcount_t			stack_refcount;
1442 #endif
1443 #ifdef CONFIG_LIVEPATCH
1444 	int patch_state;
1445 #endif
1446 #ifdef CONFIG_SECURITY
1447 	/* Used by LSM modules for access restriction: */
1448 	void				*security;
1449 #endif
1450 #ifdef CONFIG_BPF_SYSCALL
1451 	/* Used by BPF task local storage */
1452 	struct bpf_local_storage __rcu	*bpf_storage;
1453 	/* Used for BPF run context */
1454 	struct bpf_run_ctx		*bpf_ctx;
1455 #endif
1456 
1457 #ifdef CONFIG_GCC_PLUGIN_STACKLEAK
1458 	unsigned long			lowest_stack;
1459 	unsigned long			prev_lowest_stack;
1460 #endif
1461 
1462 #ifdef CONFIG_X86_MCE
1463 	void __user			*mce_vaddr;
1464 	__u64				mce_kflags;
1465 	u64				mce_addr;
1466 	__u64				mce_ripv : 1,
1467 					mce_whole_page : 1,
1468 					__mce_reserved : 62;
1469 	struct callback_head		mce_kill_me;
1470 	int				mce_count;
1471 #endif
1472 
1473 #ifdef CONFIG_KRETPROBES
1474 	struct llist_head               kretprobe_instances;
1475 #endif
1476 
1477 #ifdef CONFIG_ARCH_HAS_PARANOID_L1D_FLUSH
1478 	/*
1479 	 * If L1D flush is supported on mm context switch
1480 	 * then we use this callback head to queue kill work
1481 	 * to kill tasks that are not running on SMT disabled
1482 	 * cores
1483 	 */
1484 	struct callback_head		l1d_flush_kill;
1485 #endif
1486 
1487 	/*
1488 	 * New fields for task_struct should be added above here, so that
1489 	 * they are included in the randomized portion of task_struct.
1490 	 */
1491 	randomized_struct_fields_end
1492 
1493 	/* CPU-specific state of this task: */
1494 	struct thread_struct		thread;
1495 
1496 	/*
1497 	 * WARNING: on x86, 'thread_struct' contains a variable-sized
1498 	 * structure.  It *MUST* be at the end of 'task_struct'.
1499 	 *
1500 	 * Do not put anything below here!
1501 	 */
1502 };
1503 
task_pid(struct task_struct * task)1504 static inline struct pid *task_pid(struct task_struct *task)
1505 {
1506 	return task->thread_pid;
1507 }
1508 
1509 /*
1510  * the helpers to get the task's different pids as they are seen
1511  * from various namespaces
1512  *
1513  * task_xid_nr()     : global id, i.e. the id seen from the init namespace;
1514  * task_xid_vnr()    : virtual id, i.e. the id seen from the pid namespace of
1515  *                     current.
1516  * task_xid_nr_ns()  : id seen from the ns specified;
1517  *
1518  * see also pid_nr() etc in include/linux/pid.h
1519  */
1520 pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, struct pid_namespace *ns);
1521 
task_pid_nr(struct task_struct * tsk)1522 static inline pid_t task_pid_nr(struct task_struct *tsk)
1523 {
1524 	return tsk->pid;
1525 }
1526 
task_pid_nr_ns(struct task_struct * tsk,struct pid_namespace * ns)1527 static inline pid_t task_pid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1528 {
1529 	return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1530 }
1531 
task_pid_vnr(struct task_struct * tsk)1532 static inline pid_t task_pid_vnr(struct task_struct *tsk)
1533 {
1534 	return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1535 }
1536 
1537 
task_tgid_nr(struct task_struct * tsk)1538 static inline pid_t task_tgid_nr(struct task_struct *tsk)
1539 {
1540 	return tsk->tgid;
1541 }
1542 
1543 /**
1544  * pid_alive - check that a task structure is not stale
1545  * @p: Task structure to be checked.
1546  *
1547  * Test if a process is not yet dead (at most zombie state)
1548  * If pid_alive fails, then pointers within the task structure
1549  * can be stale and must not be dereferenced.
1550  *
1551  * Return: 1 if the process is alive. 0 otherwise.
1552  */
pid_alive(const struct task_struct * p)1553 static inline int pid_alive(const struct task_struct *p)
1554 {
1555 	return p->thread_pid != NULL;
1556 }
1557 
task_pgrp_nr_ns(struct task_struct * tsk,struct pid_namespace * ns)1558 static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1559 {
1560 	return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1561 }
1562 
task_pgrp_vnr(struct task_struct * tsk)1563 static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1564 {
1565 	return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1566 }
1567 
1568 
task_session_nr_ns(struct task_struct * tsk,struct pid_namespace * ns)1569 static inline pid_t task_session_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1570 {
1571 	return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1572 }
1573 
task_session_vnr(struct task_struct * tsk)1574 static inline pid_t task_session_vnr(struct task_struct *tsk)
1575 {
1576 	return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1577 }
1578 
task_tgid_nr_ns(struct task_struct * tsk,struct pid_namespace * ns)1579 static inline pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1580 {
1581 	return __task_pid_nr_ns(tsk, PIDTYPE_TGID, ns);
1582 }
1583 
task_tgid_vnr(struct task_struct * tsk)1584 static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1585 {
1586 	return __task_pid_nr_ns(tsk, PIDTYPE_TGID, NULL);
1587 }
1588 
task_ppid_nr_ns(const struct task_struct * tsk,struct pid_namespace * ns)1589 static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)
1590 {
1591 	pid_t pid = 0;
1592 
1593 	rcu_read_lock();
1594 	if (pid_alive(tsk))
1595 		pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
1596 	rcu_read_unlock();
1597 
1598 	return pid;
1599 }
1600 
task_ppid_nr(const struct task_struct * tsk)1601 static inline pid_t task_ppid_nr(const struct task_struct *tsk)
1602 {
1603 	return task_ppid_nr_ns(tsk, &init_pid_ns);
1604 }
1605 
1606 /* Obsolete, do not use: */
task_pgrp_nr(struct task_struct * tsk)1607 static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1608 {
1609 	return task_pgrp_nr_ns(tsk, &init_pid_ns);
1610 }
1611 
1612 #define TASK_REPORT_IDLE	(TASK_REPORT + 1)
1613 #define TASK_REPORT_MAX		(TASK_REPORT_IDLE << 1)
1614 
task_state_index(struct task_struct * tsk)1615 static inline unsigned int task_state_index(struct task_struct *tsk)
1616 {
1617 	unsigned int tsk_state = READ_ONCE(tsk->__state);
1618 	unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT;
1619 
1620 	BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
1621 
1622 	if (tsk_state == TASK_IDLE)
1623 		state = TASK_REPORT_IDLE;
1624 
1625 	return fls(state);
1626 }
1627 
task_index_to_char(unsigned int state)1628 static inline char task_index_to_char(unsigned int state)
1629 {
1630 	static const char state_char[] = "RSDTtXZPI";
1631 
1632 	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != sizeof(state_char) - 1);
1633 
1634 	return state_char[state];
1635 }
1636 
task_state_to_char(struct task_struct * tsk)1637 static inline char task_state_to_char(struct task_struct *tsk)
1638 {
1639 	return task_index_to_char(task_state_index(tsk));
1640 }
1641 
1642 /**
1643  * is_global_init - check if a task structure is init. Since init
1644  * is free to have sub-threads we need to check tgid.
1645  * @tsk: Task structure to be checked.
1646  *
1647  * Check if a task structure is the first user space task the kernel created.
1648  *
1649  * Return: 1 if the task structure is init. 0 otherwise.
1650  */
is_global_init(struct task_struct * tsk)1651 static inline int is_global_init(struct task_struct *tsk)
1652 {
1653 	return task_tgid_nr(tsk) == 1;
1654 }
1655 
1656 extern struct pid *cad_pid;
1657 
1658 /*
1659  * Per process flags
1660  */
1661 #define PF_VCPU			0x00000001	/* I'm a virtual CPU */
1662 #define PF_IDLE			0x00000002	/* I am an IDLE thread */
1663 #define PF_EXITING		0x00000004	/* Getting shut down */
1664 #define PF_POSTCOREDUMP		0x00000008	/* Coredumps should ignore this task */
1665 #define PF_IO_WORKER		0x00000010	/* Task is an IO worker */
1666 #define PF_WQ_WORKER		0x00000020	/* I'm a workqueue worker */
1667 #define PF_FORKNOEXEC		0x00000040	/* Forked but didn't exec */
1668 #define PF_MCE_PROCESS		0x00000080      /* Process policy on mce errors */
1669 #define PF_SUPERPRIV		0x00000100	/* Used super-user privileges */
1670 #define PF_DUMPCORE		0x00000200	/* Dumped core */
1671 #define PF_SIGNALED		0x00000400	/* Killed by a signal */
1672 #define PF_MEMALLOC		0x00000800	/* Allocating memory */
1673 #define PF_NPROC_EXCEEDED	0x00001000	/* set_user() noticed that RLIMIT_NPROC was exceeded */
1674 #define PF_USED_MATH		0x00002000	/* If unset the fpu must be initialized before use */
1675 #define PF_USED_ASYNC		0x00004000	/* Used async_schedule*(), used by module init */
1676 #define PF_NOFREEZE		0x00008000	/* This thread should not be frozen */
1677 #define PF_FROZEN		0x00010000	/* Frozen for system suspend */
1678 #define PF_KSWAPD		0x00020000	/* I am kswapd */
1679 #define PF_MEMALLOC_NOFS	0x00040000	/* All allocation requests will inherit GFP_NOFS */
1680 #define PF_MEMALLOC_NOIO	0x00080000	/* All allocation requests will inherit GFP_NOIO */
1681 #define PF_LOCAL_THROTTLE	0x00100000	/* Throttle writes only against the bdi I write to,
1682 						 * I am cleaning dirty pages from some other bdi. */
1683 #define PF_KTHREAD		0x00200000	/* I am a kernel thread */
1684 #define PF_RANDOMIZE		0x00400000	/* Randomize virtual address space */
1685 #define PF_SWAPWRITE		0x00800000	/* Allowed to write to swap */
1686 #define PF_NO_SETAFFINITY	0x04000000	/* Userland is not allowed to meddle with cpus_mask */
1687 #define PF_MCE_EARLY		0x08000000      /* Early kill for mce process policy */
1688 #define PF_MEMALLOC_PIN		0x10000000	/* Allocation context constrained to zones which allow long term pinning. */
1689 #define PF_FREEZER_SKIP		0x40000000	/* Freezer should not count it as freezable */
1690 #define PF_SUSPEND_TASK		0x80000000      /* This thread called freeze_processes() and should not be frozen */
1691 
1692 /*
1693  * Only the _current_ task can read/write to tsk->flags, but other
1694  * tasks can access tsk->flags in readonly mode for example
1695  * with tsk_used_math (like during threaded core dumping).
1696  * There is however an exception to this rule during ptrace
1697  * or during fork: the ptracer task is allowed to write to the
1698  * child->flags of its traced child (same goes for fork, the parent
1699  * can write to the child->flags), because we're guaranteed the
1700  * child is not running and in turn not changing child->flags
1701  * at the same time the parent does it.
1702  */
1703 #define clear_stopped_child_used_math(child)	do { (child)->flags &= ~PF_USED_MATH; } while (0)
1704 #define set_stopped_child_used_math(child)	do { (child)->flags |= PF_USED_MATH; } while (0)
1705 #define clear_used_math()			clear_stopped_child_used_math(current)
1706 #define set_used_math()				set_stopped_child_used_math(current)
1707 
1708 #define conditional_stopped_child_used_math(condition, child) \
1709 	do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1710 
1711 #define conditional_used_math(condition)	conditional_stopped_child_used_math(condition, current)
1712 
1713 #define copy_to_stopped_child_used_math(child) \
1714 	do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1715 
1716 /* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1717 #define tsk_used_math(p)			((p)->flags & PF_USED_MATH)
1718 #define used_math()				tsk_used_math(current)
1719 
is_percpu_thread(void)1720 static __always_inline bool is_percpu_thread(void)
1721 {
1722 #ifdef CONFIG_SMP
1723 	return (current->flags & PF_NO_SETAFFINITY) &&
1724 		(current->nr_cpus_allowed  == 1);
1725 #else
1726 	return true;
1727 #endif
1728 }
1729 
1730 /* Per-process atomic flags. */
1731 #define PFA_NO_NEW_PRIVS		0	/* May not gain new privileges. */
1732 #define PFA_SPREAD_PAGE			1	/* Spread page cache over cpuset */
1733 #define PFA_SPREAD_SLAB			2	/* Spread some slab caches over cpuset */
1734 #define PFA_SPEC_SSB_DISABLE		3	/* Speculative Store Bypass disabled */
1735 #define PFA_SPEC_SSB_FORCE_DISABLE	4	/* Speculative Store Bypass force disabled*/
1736 #define PFA_SPEC_IB_DISABLE		5	/* Indirect branch speculation restricted */
1737 #define PFA_SPEC_IB_FORCE_DISABLE	6	/* Indirect branch speculation permanently restricted */
1738 #define PFA_SPEC_SSB_NOEXEC		7	/* Speculative Store Bypass clear on execve() */
1739 
1740 #define TASK_PFA_TEST(name, func)					\
1741 	static inline bool task_##func(struct task_struct *p)		\
1742 	{ return test_bit(PFA_##name, &p->atomic_flags); }
1743 
1744 #define TASK_PFA_SET(name, func)					\
1745 	static inline void task_set_##func(struct task_struct *p)	\
1746 	{ set_bit(PFA_##name, &p->atomic_flags); }
1747 
1748 #define TASK_PFA_CLEAR(name, func)					\
1749 	static inline void task_clear_##func(struct task_struct *p)	\
1750 	{ clear_bit(PFA_##name, &p->atomic_flags); }
1751 
TASK_PFA_TEST(NO_NEW_PRIVS,no_new_privs)1752 TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
1753 TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
1754 
1755 TASK_PFA_TEST(SPREAD_PAGE, spread_page)
1756 TASK_PFA_SET(SPREAD_PAGE, spread_page)
1757 TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
1758 
1759 TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
1760 TASK_PFA_SET(SPREAD_SLAB, spread_slab)
1761 TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
1762 
1763 TASK_PFA_TEST(SPEC_SSB_DISABLE, spec_ssb_disable)
1764 TASK_PFA_SET(SPEC_SSB_DISABLE, spec_ssb_disable)
1765 TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
1766 
1767 TASK_PFA_TEST(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1768 TASK_PFA_SET(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1769 TASK_PFA_CLEAR(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1770 
1771 TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
1772 TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
1773 
1774 TASK_PFA_TEST(SPEC_IB_DISABLE, spec_ib_disable)
1775 TASK_PFA_SET(SPEC_IB_DISABLE, spec_ib_disable)
1776 TASK_PFA_CLEAR(SPEC_IB_DISABLE, spec_ib_disable)
1777 
1778 TASK_PFA_TEST(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
1779 TASK_PFA_SET(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
1780 
1781 static inline void
1782 current_restore_flags(unsigned long orig_flags, unsigned long flags)
1783 {
1784 	current->flags &= ~flags;
1785 	current->flags |= orig_flags & flags;
1786 }
1787 
1788 extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
1789 extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
1790 #ifdef CONFIG_SMP
1791 extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
1792 extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);
1793 extern int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node);
1794 extern void release_user_cpus_ptr(struct task_struct *p);
1795 extern int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask);
1796 extern void force_compatible_cpus_allowed_ptr(struct task_struct *p);
1797 extern void relax_compatible_cpus_allowed_ptr(struct task_struct *p);
1798 #else
do_set_cpus_allowed(struct task_struct * p,const struct cpumask * new_mask)1799 static inline void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
1800 {
1801 }
set_cpus_allowed_ptr(struct task_struct * p,const struct cpumask * new_mask)1802 static inline int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1803 {
1804 	if (!cpumask_test_cpu(0, new_mask))
1805 		return -EINVAL;
1806 	return 0;
1807 }
dup_user_cpus_ptr(struct task_struct * dst,struct task_struct * src,int node)1808 static inline int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node)
1809 {
1810 	if (src->user_cpus_ptr)
1811 		return -EINVAL;
1812 	return 0;
1813 }
release_user_cpus_ptr(struct task_struct * p)1814 static inline void release_user_cpus_ptr(struct task_struct *p)
1815 {
1816 	WARN_ON(p->user_cpus_ptr);
1817 }
1818 
dl_task_check_affinity(struct task_struct * p,const struct cpumask * mask)1819 static inline int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
1820 {
1821 	return 0;
1822 }
1823 #endif
1824 
1825 extern int yield_to(struct task_struct *p, bool preempt);
1826 extern void set_user_nice(struct task_struct *p, long nice);
1827 extern int task_prio(const struct task_struct *p);
1828 
1829 /**
1830  * task_nice - return the nice value of a given task.
1831  * @p: the task in question.
1832  *
1833  * Return: The nice value [ -20 ... 0 ... 19 ].
1834  */
task_nice(const struct task_struct * p)1835 static inline int task_nice(const struct task_struct *p)
1836 {
1837 	return PRIO_TO_NICE((p)->static_prio);
1838 }
1839 
1840 extern int can_nice(const struct task_struct *p, const int nice);
1841 extern int task_curr(const struct task_struct *p);
1842 extern int idle_cpu(int cpu);
1843 extern int available_idle_cpu(int cpu);
1844 extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *);
1845 extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *);
1846 extern void sched_set_fifo(struct task_struct *p);
1847 extern void sched_set_fifo_low(struct task_struct *p);
1848 extern void sched_set_normal(struct task_struct *p, int nice);
1849 extern int sched_setattr(struct task_struct *, const struct sched_attr *);
1850 extern int sched_setattr_nocheck(struct task_struct *, const struct sched_attr *);
1851 extern struct task_struct *idle_task(int cpu);
1852 
1853 /**
1854  * is_idle_task - is the specified task an idle task?
1855  * @p: the task in question.
1856  *
1857  * Return: 1 if @p is an idle task. 0 otherwise.
1858  */
is_idle_task(const struct task_struct * p)1859 static __always_inline bool is_idle_task(const struct task_struct *p)
1860 {
1861 	return !!(p->flags & PF_IDLE);
1862 }
1863 
1864 extern struct task_struct *curr_task(int cpu);
1865 extern void ia64_set_curr_task(int cpu, struct task_struct *p);
1866 
1867 void yield(void);
1868 
1869 union thread_union {
1870 #ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK
1871 	struct task_struct task;
1872 #endif
1873 #ifndef CONFIG_THREAD_INFO_IN_TASK
1874 	struct thread_info thread_info;
1875 #endif
1876 	unsigned long stack[THREAD_SIZE/sizeof(long)];
1877 };
1878 
1879 #ifndef CONFIG_THREAD_INFO_IN_TASK
1880 extern struct thread_info init_thread_info;
1881 #endif
1882 
1883 extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)];
1884 
1885 #ifdef CONFIG_THREAD_INFO_IN_TASK
1886 # define task_thread_info(task)	(&(task)->thread_info)
1887 #elif !defined(__HAVE_THREAD_FUNCTIONS)
1888 # define task_thread_info(task)	((struct thread_info *)(task)->stack)
1889 #endif
1890 
1891 /*
1892  * find a task by one of its numerical ids
1893  *
1894  * find_task_by_pid_ns():
1895  *      finds a task by its pid in the specified namespace
1896  * find_task_by_vpid():
1897  *      finds a task by its virtual pid
1898  *
1899  * see also find_vpid() etc in include/linux/pid.h
1900  */
1901 
1902 extern struct task_struct *find_task_by_vpid(pid_t nr);
1903 extern struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns);
1904 
1905 /*
1906  * find a task by its virtual pid and get the task struct
1907  */
1908 extern struct task_struct *find_get_task_by_vpid(pid_t nr);
1909 
1910 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
1911 extern int wake_up_process(struct task_struct *tsk);
1912 extern void wake_up_new_task(struct task_struct *tsk);
1913 
1914 #ifdef CONFIG_SMP
1915 extern void kick_process(struct task_struct *tsk);
1916 #else
kick_process(struct task_struct * tsk)1917 static inline void kick_process(struct task_struct *tsk) { }
1918 #endif
1919 
1920 extern void __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
1921 
set_task_comm(struct task_struct * tsk,const char * from)1922 static inline void set_task_comm(struct task_struct *tsk, const char *from)
1923 {
1924 	__set_task_comm(tsk, from, false);
1925 }
1926 
1927 extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
1928 #define get_task_comm(buf, tsk) ({			\
1929 	BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN);	\
1930 	__get_task_comm(buf, sizeof(buf), tsk);		\
1931 })
1932 
1933 #ifdef CONFIG_SMP
scheduler_ipi(void)1934 static __always_inline void scheduler_ipi(void)
1935 {
1936 	/*
1937 	 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1938 	 * TIF_NEED_RESCHED remotely (for the first time) will also send
1939 	 * this IPI.
1940 	 */
1941 	preempt_fold_need_resched();
1942 }
1943 extern unsigned long wait_task_inactive(struct task_struct *, unsigned int match_state);
1944 #else
scheduler_ipi(void)1945 static inline void scheduler_ipi(void) { }
wait_task_inactive(struct task_struct * p,unsigned int match_state)1946 static inline unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
1947 {
1948 	return 1;
1949 }
1950 #endif
1951 
1952 /*
1953  * Set thread flags in other task's structures.
1954  * See asm/thread_info.h for TIF_xxxx flags available:
1955  */
set_tsk_thread_flag(struct task_struct * tsk,int flag)1956 static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
1957 {
1958 	set_ti_thread_flag(task_thread_info(tsk), flag);
1959 }
1960 
clear_tsk_thread_flag(struct task_struct * tsk,int flag)1961 static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1962 {
1963 	clear_ti_thread_flag(task_thread_info(tsk), flag);
1964 }
1965 
update_tsk_thread_flag(struct task_struct * tsk,int flag,bool value)1966 static inline void update_tsk_thread_flag(struct task_struct *tsk, int flag,
1967 					  bool value)
1968 {
1969 	update_ti_thread_flag(task_thread_info(tsk), flag, value);
1970 }
1971 
test_and_set_tsk_thread_flag(struct task_struct * tsk,int flag)1972 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
1973 {
1974 	return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
1975 }
1976 
test_and_clear_tsk_thread_flag(struct task_struct * tsk,int flag)1977 static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1978 {
1979 	return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
1980 }
1981 
test_tsk_thread_flag(struct task_struct * tsk,int flag)1982 static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
1983 {
1984 	return test_ti_thread_flag(task_thread_info(tsk), flag);
1985 }
1986 
set_tsk_need_resched(struct task_struct * tsk)1987 static inline void set_tsk_need_resched(struct task_struct *tsk)
1988 {
1989 	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
1990 }
1991 
clear_tsk_need_resched(struct task_struct * tsk)1992 static inline void clear_tsk_need_resched(struct task_struct *tsk)
1993 {
1994 	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
1995 }
1996 
test_tsk_need_resched(struct task_struct * tsk)1997 static inline int test_tsk_need_resched(struct task_struct *tsk)
1998 {
1999 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
2000 }
2001 
2002 /*
2003  * cond_resched() and cond_resched_lock(): latency reduction via
2004  * explicit rescheduling in places that are safe. The return
2005  * value indicates whether a reschedule was done in fact.
2006  * cond_resched_lock() will drop the spinlock before scheduling,
2007  */
2008 #if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
2009 extern int __cond_resched(void);
2010 
2011 #ifdef CONFIG_PREEMPT_DYNAMIC
2012 
2013 DECLARE_STATIC_CALL(cond_resched, __cond_resched);
2014 
_cond_resched(void)2015 static __always_inline int _cond_resched(void)
2016 {
2017 	return static_call_mod(cond_resched)();
2018 }
2019 
2020 #else
2021 
_cond_resched(void)2022 static inline int _cond_resched(void)
2023 {
2024 	return __cond_resched();
2025 }
2026 
2027 #endif /* CONFIG_PREEMPT_DYNAMIC */
2028 
2029 #else
2030 
_cond_resched(void)2031 static inline int _cond_resched(void) { return 0; }
2032 
2033 #endif /* !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) */
2034 
2035 #define cond_resched() ({			\
2036 	__might_resched(__FILE__, __LINE__, 0);	\
2037 	_cond_resched();			\
2038 })
2039 
2040 extern int __cond_resched_lock(spinlock_t *lock);
2041 extern int __cond_resched_rwlock_read(rwlock_t *lock);
2042 extern int __cond_resched_rwlock_write(rwlock_t *lock);
2043 
2044 #define MIGHT_RESCHED_RCU_SHIFT		8
2045 #define MIGHT_RESCHED_PREEMPT_MASK	((1U << MIGHT_RESCHED_RCU_SHIFT) - 1)
2046 
2047 #ifndef CONFIG_PREEMPT_RT
2048 /*
2049  * Non RT kernels have an elevated preempt count due to the held lock,
2050  * but are not allowed to be inside a RCU read side critical section
2051  */
2052 # define PREEMPT_LOCK_RESCHED_OFFSETS	PREEMPT_LOCK_OFFSET
2053 #else
2054 /*
2055  * spin/rw_lock() on RT implies rcu_read_lock(). The might_sleep() check in
2056  * cond_resched*lock() has to take that into account because it checks for
2057  * preempt_count() and rcu_preempt_depth().
2058  */
2059 # define PREEMPT_LOCK_RESCHED_OFFSETS	\
2060 	(PREEMPT_LOCK_OFFSET + (1U << MIGHT_RESCHED_RCU_SHIFT))
2061 #endif
2062 
2063 #define cond_resched_lock(lock) ({						\
2064 	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);	\
2065 	__cond_resched_lock(lock);						\
2066 })
2067 
2068 #define cond_resched_rwlock_read(lock) ({					\
2069 	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);	\
2070 	__cond_resched_rwlock_read(lock);					\
2071 })
2072 
2073 #define cond_resched_rwlock_write(lock) ({					\
2074 	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);	\
2075 	__cond_resched_rwlock_write(lock);					\
2076 })
2077 
cond_resched_rcu(void)2078 static inline void cond_resched_rcu(void)
2079 {
2080 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
2081 	rcu_read_unlock();
2082 	cond_resched();
2083 	rcu_read_lock();
2084 #endif
2085 }
2086 
2087 /*
2088  * Does a critical section need to be broken due to another
2089  * task waiting?: (technically does not depend on CONFIG_PREEMPTION,
2090  * but a general need for low latency)
2091  */
spin_needbreak(spinlock_t * lock)2092 static inline int spin_needbreak(spinlock_t *lock)
2093 {
2094 #ifdef CONFIG_PREEMPTION
2095 	return spin_is_contended(lock);
2096 #else
2097 	return 0;
2098 #endif
2099 }
2100 
2101 /*
2102  * Check if a rwlock is contended.
2103  * Returns non-zero if there is another task waiting on the rwlock.
2104  * Returns zero if the lock is not contended or the system / underlying
2105  * rwlock implementation does not support contention detection.
2106  * Technically does not depend on CONFIG_PREEMPTION, but a general need
2107  * for low latency.
2108  */
rwlock_needbreak(rwlock_t * lock)2109 static inline int rwlock_needbreak(rwlock_t *lock)
2110 {
2111 #ifdef CONFIG_PREEMPTION
2112 	return rwlock_is_contended(lock);
2113 #else
2114 	return 0;
2115 #endif
2116 }
2117 
need_resched(void)2118 static __always_inline bool need_resched(void)
2119 {
2120 	return unlikely(tif_need_resched());
2121 }
2122 
2123 /*
2124  * Wrappers for p->thread_info->cpu access. No-op on UP.
2125  */
2126 #ifdef CONFIG_SMP
2127 
task_cpu(const struct task_struct * p)2128 static inline unsigned int task_cpu(const struct task_struct *p)
2129 {
2130 	return READ_ONCE(task_thread_info(p)->cpu);
2131 }
2132 
2133 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
2134 
2135 #else
2136 
task_cpu(const struct task_struct * p)2137 static inline unsigned int task_cpu(const struct task_struct *p)
2138 {
2139 	return 0;
2140 }
2141 
set_task_cpu(struct task_struct * p,unsigned int cpu)2142 static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
2143 {
2144 }
2145 
2146 #endif /* CONFIG_SMP */
2147 
2148 extern bool sched_task_on_rq(struct task_struct *p);
2149 extern unsigned long get_wchan(struct task_struct *p);
2150 
2151 /*
2152  * In order to reduce various lock holder preemption latencies provide an
2153  * interface to see if a vCPU is currently running or not.
2154  *
2155  * This allows us to terminate optimistic spin loops and block, analogous to
2156  * the native optimistic spin heuristic of testing if the lock owner task is
2157  * running or not.
2158  */
2159 #ifndef vcpu_is_preempted
vcpu_is_preempted(int cpu)2160 static inline bool vcpu_is_preempted(int cpu)
2161 {
2162 	return false;
2163 }
2164 #endif
2165 
2166 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
2167 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
2168 
2169 #ifndef TASK_SIZE_OF
2170 #define TASK_SIZE_OF(tsk)	TASK_SIZE
2171 #endif
2172 
2173 #ifdef CONFIG_SMP
2174 /* Returns effective CPU energy utilization, as seen by the scheduler */
2175 unsigned long sched_cpu_util(int cpu, unsigned long max);
2176 #endif /* CONFIG_SMP */
2177 
2178 #ifdef CONFIG_RSEQ
2179 
2180 /*
2181  * Map the event mask on the user-space ABI enum rseq_cs_flags
2182  * for direct mask checks.
2183  */
2184 enum rseq_event_mask_bits {
2185 	RSEQ_EVENT_PREEMPT_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
2186 	RSEQ_EVENT_SIGNAL_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
2187 	RSEQ_EVENT_MIGRATE_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
2188 };
2189 
2190 enum rseq_event_mask {
2191 	RSEQ_EVENT_PREEMPT	= (1U << RSEQ_EVENT_PREEMPT_BIT),
2192 	RSEQ_EVENT_SIGNAL	= (1U << RSEQ_EVENT_SIGNAL_BIT),
2193 	RSEQ_EVENT_MIGRATE	= (1U << RSEQ_EVENT_MIGRATE_BIT),
2194 };
2195 
rseq_set_notify_resume(struct task_struct * t)2196 static inline void rseq_set_notify_resume(struct task_struct *t)
2197 {
2198 	if (t->rseq)
2199 		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
2200 }
2201 
2202 void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
2203 
rseq_handle_notify_resume(struct ksignal * ksig,struct pt_regs * regs)2204 static inline void rseq_handle_notify_resume(struct ksignal *ksig,
2205 					     struct pt_regs *regs)
2206 {
2207 	if (current->rseq)
2208 		__rseq_handle_notify_resume(ksig, regs);
2209 }
2210 
rseq_signal_deliver(struct ksignal * ksig,struct pt_regs * regs)2211 static inline void rseq_signal_deliver(struct ksignal *ksig,
2212 				       struct pt_regs *regs)
2213 {
2214 	preempt_disable();
2215 	__set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
2216 	preempt_enable();
2217 	rseq_handle_notify_resume(ksig, regs);
2218 }
2219 
2220 /* rseq_preempt() requires preemption to be disabled. */
rseq_preempt(struct task_struct * t)2221 static inline void rseq_preempt(struct task_struct *t)
2222 {
2223 	__set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
2224 	rseq_set_notify_resume(t);
2225 }
2226 
2227 /* rseq_migrate() requires preemption to be disabled. */
rseq_migrate(struct task_struct * t)2228 static inline void rseq_migrate(struct task_struct *t)
2229 {
2230 	__set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
2231 	rseq_set_notify_resume(t);
2232 }
2233 
2234 /*
2235  * If parent process has a registered restartable sequences area, the
2236  * child inherits. Unregister rseq for a clone with CLONE_VM set.
2237  */
rseq_fork(struct task_struct * t,unsigned long clone_flags)2238 static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
2239 {
2240 	if (clone_flags & CLONE_VM) {
2241 		t->rseq = NULL;
2242 		t->rseq_sig = 0;
2243 		t->rseq_event_mask = 0;
2244 	} else {
2245 		t->rseq = current->rseq;
2246 		t->rseq_sig = current->rseq_sig;
2247 		t->rseq_event_mask = current->rseq_event_mask;
2248 	}
2249 }
2250 
rseq_execve(struct task_struct * t)2251 static inline void rseq_execve(struct task_struct *t)
2252 {
2253 	t->rseq = NULL;
2254 	t->rseq_sig = 0;
2255 	t->rseq_event_mask = 0;
2256 }
2257 
2258 #else
2259 
rseq_set_notify_resume(struct task_struct * t)2260 static inline void rseq_set_notify_resume(struct task_struct *t)
2261 {
2262 }
rseq_handle_notify_resume(struct ksignal * ksig,struct pt_regs * regs)2263 static inline void rseq_handle_notify_resume(struct ksignal *ksig,
2264 					     struct pt_regs *regs)
2265 {
2266 }
rseq_signal_deliver(struct ksignal * ksig,struct pt_regs * regs)2267 static inline void rseq_signal_deliver(struct ksignal *ksig,
2268 				       struct pt_regs *regs)
2269 {
2270 }
rseq_preempt(struct task_struct * t)2271 static inline void rseq_preempt(struct task_struct *t)
2272 {
2273 }
rseq_migrate(struct task_struct * t)2274 static inline void rseq_migrate(struct task_struct *t)
2275 {
2276 }
rseq_fork(struct task_struct * t,unsigned long clone_flags)2277 static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
2278 {
2279 }
rseq_execve(struct task_struct * t)2280 static inline void rseq_execve(struct task_struct *t)
2281 {
2282 }
2283 
2284 #endif
2285 
2286 #ifdef CONFIG_DEBUG_RSEQ
2287 
2288 void rseq_syscall(struct pt_regs *regs);
2289 
2290 #else
2291 
rseq_syscall(struct pt_regs * regs)2292 static inline void rseq_syscall(struct pt_regs *regs)
2293 {
2294 }
2295 
2296 #endif
2297 
2298 const struct sched_avg *sched_trace_cfs_rq_avg(struct cfs_rq *cfs_rq);
2299 char *sched_trace_cfs_rq_path(struct cfs_rq *cfs_rq, char *str, int len);
2300 int sched_trace_cfs_rq_cpu(struct cfs_rq *cfs_rq);
2301 
2302 const struct sched_avg *sched_trace_rq_avg_rt(struct rq *rq);
2303 const struct sched_avg *sched_trace_rq_avg_dl(struct rq *rq);
2304 const struct sched_avg *sched_trace_rq_avg_irq(struct rq *rq);
2305 
2306 int sched_trace_rq_cpu(struct rq *rq);
2307 int sched_trace_rq_cpu_capacity(struct rq *rq);
2308 int sched_trace_rq_nr_running(struct rq *rq);
2309 
2310 const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
2311 
2312 #ifdef CONFIG_SCHED_CORE
2313 extern void sched_core_free(struct task_struct *tsk);
2314 extern void sched_core_fork(struct task_struct *p);
2315 extern int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type,
2316 				unsigned long uaddr);
2317 #else
sched_core_free(struct task_struct * tsk)2318 static inline void sched_core_free(struct task_struct *tsk) { }
sched_core_fork(struct task_struct * p)2319 static inline void sched_core_fork(struct task_struct *p) { }
2320 #endif
2321 
2322 #endif
2323