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): */
40struct audit_context;
41struct backing_dev_info;
42struct bio_list;
43struct blk_plug;
44struct bpf_local_storage;
45struct bpf_run_ctx;
46struct capture_control;
47struct cfs_rq;
48struct fs_struct;
49struct futex_pi_state;
50struct io_context;
51struct io_uring_task;
52struct mempolicy;
53struct nameidata;
54struct nsproxy;
55struct perf_event_context;
56struct pid_namespace;
57struct pipe_inode_info;
58struct rcu_node;
59struct reclaim_state;
60struct robust_list_head;
61struct root_domain;
62struct rq;
63struct sched_attr;
64struct sched_param;
65struct seq_file;
66struct sighand_struct;
67struct signal_struct;
68struct task_delay_info;
69struct 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_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->jobctl) & JOBCTL_TRACED) != 0)
122#define task_is_stopped(task)		((READ_ONCE(task->jobctl) & JOBCTL_STOPPED) != 0)
123#define task_is_stopped_or_traced(task)	((READ_ONCE(task->jobctl) & (JOBCTL_STOPPED | JOBCTL_TRACED)) != 0)
124
125/*
126 * Special states are those that do not use the normal wait-loop pattern. See
127 * the comment with set_special_state().
128 */
129#define is_special_task_state(state)				\
130	((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | TASK_DEAD))
131
132#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
133# define debug_normal_state_change(state_value)				\
134	do {								\
135		WARN_ON_ONCE(is_special_task_state(state_value));	\
136		current->task_state_change = _THIS_IP_;			\
137	} while (0)
138
139# define debug_special_state_change(state_value)			\
140	do {								\
141		WARN_ON_ONCE(!is_special_task_state(state_value));	\
142		current->task_state_change = _THIS_IP_;			\
143	} while (0)
144
145# define debug_rtlock_wait_set_state()					\
146	do {								 \
147		current->saved_state_change = current->task_state_change;\
148		current->task_state_change = _THIS_IP_;			 \
149	} while (0)
150
151# define debug_rtlock_wait_restore_state()				\
152	do {								 \
153		current->task_state_change = current->saved_state_change;\
154	} while (0)
155
156#else
157# define debug_normal_state_change(cond)	do { } while (0)
158# define debug_special_state_change(cond)	do { } while (0)
159# define debug_rtlock_wait_set_state()		do { } while (0)
160# define debug_rtlock_wait_restore_state()	do { } while (0)
161#endif
162
163/*
164 * set_current_state() includes a barrier so that the write of current->state
165 * is correctly serialised wrt the caller's subsequent test of whether to
166 * actually sleep:
167 *
168 *   for (;;) {
169 *	set_current_state(TASK_UNINTERRUPTIBLE);
170 *	if (CONDITION)
171 *	   break;
172 *
173 *	schedule();
174 *   }
175 *   __set_current_state(TASK_RUNNING);
176 *
177 * If the caller does not need such serialisation (because, for instance, the
178 * CONDITION test and condition change and wakeup are under the same lock) then
179 * use __set_current_state().
180 *
181 * The above is typically ordered against the wakeup, which does:
182 *
183 *   CONDITION = 1;
184 *   wake_up_state(p, TASK_UNINTERRUPTIBLE);
185 *
186 * where wake_up_state()/try_to_wake_up() executes a full memory barrier before
187 * accessing p->state.
188 *
189 * Wakeup will do: if (@state & p->state) p->state = TASK_RUNNING, that is,
190 * once it observes the TASK_UNINTERRUPTIBLE store the waking CPU can issue a
191 * TASK_RUNNING store which can collide with __set_current_state(TASK_RUNNING).
192 *
193 * However, with slightly different timing the wakeup TASK_RUNNING store can
194 * also collide with the TASK_UNINTERRUPTIBLE store. Losing that store is not
195 * a problem either because that will result in one extra go around the loop
196 * and our @cond test will save the day.
197 *
198 * Also see the comments of try_to_wake_up().
199 */
200#define __set_current_state(state_value)				\
201	do {								\
202		debug_normal_state_change((state_value));		\
203		WRITE_ONCE(current->__state, (state_value));		\
204	} while (0)
205
206#define set_current_state(state_value)					\
207	do {								\
208		debug_normal_state_change((state_value));		\
209		smp_store_mb(current->__state, (state_value));		\
210	} while (0)
211
212/*
213 * set_special_state() should be used for those states when the blocking task
214 * can not use the regular condition based wait-loop. In that case we must
215 * serialize against wakeups such that any possible in-flight TASK_RUNNING
216 * stores will not collide with our state change.
217 */
218#define set_special_state(state_value)					\
219	do {								\
220		unsigned long flags; /* may shadow */			\
221									\
222		raw_spin_lock_irqsave(&current->pi_lock, flags);	\
223		debug_special_state_change((state_value));		\
224		WRITE_ONCE(current->__state, (state_value));		\
225		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	\
226	} while (0)
227
228/*
229 * PREEMPT_RT specific variants for "sleeping" spin/rwlocks
230 *
231 * RT's spin/rwlock substitutions are state preserving. The state of the
232 * task when blocking on the lock is saved in task_struct::saved_state and
233 * restored after the lock has been acquired.  These operations are
234 * serialized by task_struct::pi_lock against try_to_wake_up(). Any non RT
235 * lock related wakeups while the task is blocked on the lock are
236 * redirected to operate on task_struct::saved_state to ensure that these
237 * are not dropped. On restore task_struct::saved_state is set to
238 * TASK_RUNNING so any wakeup attempt redirected to saved_state will fail.
239 *
240 * The lock operation looks like this:
241 *
242 *	current_save_and_set_rtlock_wait_state();
243 *	for (;;) {
244 *		if (try_lock())
245 *			break;
246 *		raw_spin_unlock_irq(&lock->wait_lock);
247 *		schedule_rtlock();
248 *		raw_spin_lock_irq(&lock->wait_lock);
249 *		set_current_state(TASK_RTLOCK_WAIT);
250 *	}
251 *	current_restore_rtlock_saved_state();
252 */
253#define current_save_and_set_rtlock_wait_state()			\
254	do {								\
255		lockdep_assert_irqs_disabled();				\
256		raw_spin_lock(&current->pi_lock);			\
257		current->saved_state = current->__state;		\
258		debug_rtlock_wait_set_state();				\
259		WRITE_ONCE(current->__state, TASK_RTLOCK_WAIT);		\
260		raw_spin_unlock(&current->pi_lock);			\
261	} while (0);
262
263#define current_restore_rtlock_saved_state()				\
264	do {								\
265		lockdep_assert_irqs_disabled();				\
266		raw_spin_lock(&current->pi_lock);			\
267		debug_rtlock_wait_restore_state();			\
268		WRITE_ONCE(current->__state, current->saved_state);	\
269		current->saved_state = TASK_RUNNING;			\
270		raw_spin_unlock(&current->pi_lock);			\
271	} while (0);
272
273#define get_current_state()	READ_ONCE(current->__state)
274
275/*
276 * Define the task command name length as enum, then it can be visible to
277 * BPF programs.
278 */
279enum {
280	TASK_COMM_LEN = 16,
281};
282
283extern void scheduler_tick(void);
284
285#define	MAX_SCHEDULE_TIMEOUT		LONG_MAX
286
287extern long schedule_timeout(long timeout);
288extern long schedule_timeout_interruptible(long timeout);
289extern long schedule_timeout_killable(long timeout);
290extern long schedule_timeout_uninterruptible(long timeout);
291extern long schedule_timeout_idle(long timeout);
292asmlinkage void schedule(void);
293extern void schedule_preempt_disabled(void);
294asmlinkage void preempt_schedule_irq(void);
295#ifdef CONFIG_PREEMPT_RT
296 extern void schedule_rtlock(void);
297#endif
298
299extern int __must_check io_schedule_prepare(void);
300extern void io_schedule_finish(int token);
301extern long io_schedule_timeout(long timeout);
302extern void io_schedule(void);
303
304/**
305 * struct prev_cputime - snapshot of system and user cputime
306 * @utime: time spent in user mode
307 * @stime: time spent in system mode
308 * @lock: protects the above two fields
309 *
310 * Stores previous user/system time values such that we can guarantee
311 * monotonicity.
312 */
313struct prev_cputime {
314#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
315	u64				utime;
316	u64				stime;
317	raw_spinlock_t			lock;
318#endif
319};
320
321enum vtime_state {
322	/* Task is sleeping or running in a CPU with VTIME inactive: */
323	VTIME_INACTIVE = 0,
324	/* Task is idle */
325	VTIME_IDLE,
326	/* Task runs in kernelspace in a CPU with VTIME active: */
327	VTIME_SYS,
328	/* Task runs in userspace in a CPU with VTIME active: */
329	VTIME_USER,
330	/* Task runs as guests in a CPU with VTIME active: */
331	VTIME_GUEST,
332};
333
334struct vtime {
335	seqcount_t		seqcount;
336	unsigned long long	starttime;
337	enum vtime_state	state;
338	unsigned int		cpu;
339	u64			utime;
340	u64			stime;
341	u64			gtime;
342};
343
344/*
345 * Utilization clamp constraints.
346 * @UCLAMP_MIN:	Minimum utilization
347 * @UCLAMP_MAX:	Maximum utilization
348 * @UCLAMP_CNT:	Utilization clamp constraints count
349 */
350enum uclamp_id {
351	UCLAMP_MIN = 0,
352	UCLAMP_MAX,
353	UCLAMP_CNT
354};
355
356#ifdef CONFIG_SMP
357extern struct root_domain def_root_domain;
358extern struct mutex sched_domains_mutex;
359#endif
360
361struct sched_info {
362#ifdef CONFIG_SCHED_INFO
363	/* Cumulative counters: */
364
365	/* # of times we have run on this CPU: */
366	unsigned long			pcount;
367
368	/* Time spent waiting on a runqueue: */
369	unsigned long long		run_delay;
370
371	/* Timestamps: */
372
373	/* When did we last run on a CPU? */
374	unsigned long long		last_arrival;
375
376	/* When were we last queued to run? */
377	unsigned long long		last_queued;
378
379#endif /* CONFIG_SCHED_INFO */
380};
381
382/*
383 * Integer metrics need fixed point arithmetic, e.g., sched/fair
384 * has a few: load, load_avg, util_avg, freq, and capacity.
385 *
386 * We define a basic fixed point arithmetic range, and then formalize
387 * all these metrics based on that basic range.
388 */
389# define SCHED_FIXEDPOINT_SHIFT		10
390# define SCHED_FIXEDPOINT_SCALE		(1L << SCHED_FIXEDPOINT_SHIFT)
391
392/* Increase resolution of cpu_capacity calculations */
393# define SCHED_CAPACITY_SHIFT		SCHED_FIXEDPOINT_SHIFT
394# define SCHED_CAPACITY_SCALE		(1L << SCHED_CAPACITY_SHIFT)
395
396struct load_weight {
397	unsigned long			weight;
398	u32				inv_weight;
399};
400
401/**
402 * struct util_est - Estimation utilization of FAIR tasks
403 * @enqueued: instantaneous estimated utilization of a task/cpu
404 * @ewma:     the Exponential Weighted Moving Average (EWMA)
405 *            utilization of a task
406 *
407 * Support data structure to track an Exponential Weighted Moving Average
408 * (EWMA) of a FAIR task's utilization. New samples are added to the moving
409 * average each time a task completes an activation. Sample's weight is chosen
410 * so that the EWMA will be relatively insensitive to transient changes to the
411 * task's workload.
412 *
413 * The enqueued attribute has a slightly different meaning for tasks and cpus:
414 * - task:   the task's util_avg at last task dequeue time
415 * - cfs_rq: the sum of util_est.enqueued for each RUNNABLE task on that CPU
416 * Thus, the util_est.enqueued of a task represents the contribution on the
417 * estimated utilization of the CPU where that task is currently enqueued.
418 *
419 * Only for tasks we track a moving average of the past instantaneous
420 * estimated utilization. This allows to absorb sporadic drops in utilization
421 * of an otherwise almost periodic task.
422 *
423 * The UTIL_AVG_UNCHANGED flag is used to synchronize util_est with util_avg
424 * updates. When a task is dequeued, its util_est should not be updated if its
425 * util_avg has not been updated in the meantime.
426 * This information is mapped into the MSB bit of util_est.enqueued at dequeue
427 * time. Since max value of util_est.enqueued for a task is 1024 (PELT util_avg
428 * for a task) it is safe to use MSB.
429 */
430struct util_est {
431	unsigned int			enqueued;
432	unsigned int			ewma;
433#define UTIL_EST_WEIGHT_SHIFT		2
434#define UTIL_AVG_UNCHANGED		0x80000000
435} __attribute__((__aligned__(sizeof(u64))));
436
437/*
438 * The load/runnable/util_avg accumulates an infinite geometric series
439 * (see __update_load_avg_cfs_rq() in kernel/sched/pelt.c).
440 *
441 * [load_avg definition]
442 *
443 *   load_avg = runnable% * scale_load_down(load)
444 *
445 * [runnable_avg definition]
446 *
447 *   runnable_avg = runnable% * SCHED_CAPACITY_SCALE
448 *
449 * [util_avg definition]
450 *
451 *   util_avg = running% * SCHED_CAPACITY_SCALE
452 *
453 * where runnable% is the time ratio that a sched_entity is runnable and
454 * running% the time ratio that a sched_entity is running.
455 *
456 * For cfs_rq, they are the aggregated values of all runnable and blocked
457 * sched_entities.
458 *
459 * The load/runnable/util_avg doesn't directly factor frequency scaling and CPU
460 * capacity scaling. The scaling is done through the rq_clock_pelt that is used
461 * for computing those signals (see update_rq_clock_pelt())
462 *
463 * N.B., the above ratios (runnable% and running%) themselves are in the
464 * range of [0, 1]. To do fixed point arithmetics, we therefore scale them
465 * to as large a range as necessary. This is for example reflected by
466 * util_avg's SCHED_CAPACITY_SCALE.
467 *
468 * [Overflow issue]
469 *
470 * The 64-bit load_sum can have 4353082796 (=2^64/47742/88761) entities
471 * with the highest load (=88761), always runnable on a single cfs_rq,
472 * and should not overflow as the number already hits PID_MAX_LIMIT.
473 *
474 * For all other cases (including 32-bit kernels), struct load_weight's
475 * weight will overflow first before we do, because:
476 *
477 *    Max(load_avg) <= Max(load.weight)
478 *
479 * Then it is the load_weight's responsibility to consider overflow
480 * issues.
481 */
482struct sched_avg {
483	u64				last_update_time;
484	u64				load_sum;
485	u64				runnable_sum;
486	u32				util_sum;
487	u32				period_contrib;
488	unsigned long			load_avg;
489	unsigned long			runnable_avg;
490	unsigned long			util_avg;
491	struct util_est			util_est;
492} ____cacheline_aligned;
493
494struct sched_statistics {
495#ifdef CONFIG_SCHEDSTATS
496	u64				wait_start;
497	u64				wait_max;
498	u64				wait_count;
499	u64				wait_sum;
500	u64				iowait_count;
501	u64				iowait_sum;
502
503	u64				sleep_start;
504	u64				sleep_max;
505	s64				sum_sleep_runtime;
506
507	u64				block_start;
508	u64				block_max;
509	s64				sum_block_runtime;
510
511	u64				exec_max;
512	u64				slice_max;
513
514	u64				nr_migrations_cold;
515	u64				nr_failed_migrations_affine;
516	u64				nr_failed_migrations_running;
517	u64				nr_failed_migrations_hot;
518	u64				nr_forced_migrations;
519
520	u64				nr_wakeups;
521	u64				nr_wakeups_sync;
522	u64				nr_wakeups_migrate;
523	u64				nr_wakeups_local;
524	u64				nr_wakeups_remote;
525	u64				nr_wakeups_affine;
526	u64				nr_wakeups_affine_attempts;
527	u64				nr_wakeups_passive;
528	u64				nr_wakeups_idle;
529
530#ifdef CONFIG_SCHED_CORE
531	u64				core_forceidle_sum;
532#endif
533#endif /* CONFIG_SCHEDSTATS */
534} ____cacheline_aligned;
535
536struct sched_entity {
537	/* For load-balancing: */
538	struct load_weight		load;
539	struct rb_node			run_node;
540	struct list_head		group_node;
541	unsigned int			on_rq;
542
543	u64				exec_start;
544	u64				sum_exec_runtime;
545	u64				vruntime;
546	u64				prev_sum_exec_runtime;
547
548	u64				nr_migrations;
549
550#ifdef CONFIG_FAIR_GROUP_SCHED
551	int				depth;
552	struct sched_entity		*parent;
553	/* rq on which this entity is (to be) queued: */
554	struct cfs_rq			*cfs_rq;
555	/* rq "owned" by this entity/group: */
556	struct cfs_rq			*my_q;
557	/* cached value of my_q->h_nr_running */
558	unsigned long			runnable_weight;
559#endif
560
561#ifdef CONFIG_SMP
562	/*
563	 * Per entity load average tracking.
564	 *
565	 * Put into separate cache line so it does not
566	 * collide with read-mostly values above.
567	 */
568	struct sched_avg		avg;
569#endif
570};
571
572struct sched_rt_entity {
573	struct list_head		run_list;
574	unsigned long			timeout;
575	unsigned long			watchdog_stamp;
576	unsigned int			time_slice;
577	unsigned short			on_rq;
578	unsigned short			on_list;
579
580	struct sched_rt_entity		*back;
581#ifdef CONFIG_RT_GROUP_SCHED
582	struct sched_rt_entity		*parent;
583	/* rq on which this entity is (to be) queued: */
584	struct rt_rq			*rt_rq;
585	/* rq "owned" by this entity/group: */
586	struct rt_rq			*my_q;
587#endif
588} __randomize_layout;
589
590struct sched_dl_entity {
591	struct rb_node			rb_node;
592
593	/*
594	 * Original scheduling parameters. Copied here from sched_attr
595	 * during sched_setattr(), they will remain the same until
596	 * the next sched_setattr().
597	 */
598	u64				dl_runtime;	/* Maximum runtime for each instance	*/
599	u64				dl_deadline;	/* Relative deadline of each instance	*/
600	u64				dl_period;	/* Separation of two instances (period) */
601	u64				dl_bw;		/* dl_runtime / dl_period		*/
602	u64				dl_density;	/* dl_runtime / dl_deadline		*/
603
604	/*
605	 * Actual scheduling parameters. Initialized with the values above,
606	 * they are continuously updated during task execution. Note that
607	 * the remaining runtime could be < 0 in case we are in overrun.
608	 */
609	s64				runtime;	/* Remaining runtime for this instance	*/
610	u64				deadline;	/* Absolute deadline for this instance	*/
611	unsigned int			flags;		/* Specifying the scheduler behaviour	*/
612
613	/*
614	 * Some bool flags:
615	 *
616	 * @dl_throttled tells if we exhausted the runtime. If so, the
617	 * task has to wait for a replenishment to be performed at the
618	 * next firing of dl_timer.
619	 *
620	 * @dl_yielded tells if task gave up the CPU before consuming
621	 * all its available runtime during the last job.
622	 *
623	 * @dl_non_contending tells if the task is inactive while still
624	 * contributing to the active utilization. In other words, it
625	 * indicates if the inactive timer has been armed and its handler
626	 * has not been executed yet. This flag is useful to avoid race
627	 * conditions between the inactive timer handler and the wakeup
628	 * code.
629	 *
630	 * @dl_overrun tells if the task asked to be informed about runtime
631	 * overruns.
632	 */
633	unsigned int			dl_throttled      : 1;
634	unsigned int			dl_yielded        : 1;
635	unsigned int			dl_non_contending : 1;
636	unsigned int			dl_overrun	  : 1;
637
638	/*
639	 * Bandwidth enforcement timer. Each -deadline task has its
640	 * own bandwidth to be enforced, thus we need one timer per task.
641	 */
642	struct hrtimer			dl_timer;
643
644	/*
645	 * Inactive timer, responsible for decreasing the active utilization
646	 * at the "0-lag time". When a -deadline task blocks, it contributes
647	 * to GRUB's active utilization until the "0-lag time", hence a
648	 * timer is needed to decrease the active utilization at the correct
649	 * time.
650	 */
651	struct hrtimer inactive_timer;
652
653#ifdef CONFIG_RT_MUTEXES
654	/*
655	 * Priority Inheritance. When a DEADLINE scheduling entity is boosted
656	 * pi_se points to the donor, otherwise points to the dl_se it belongs
657	 * to (the original one/itself).
658	 */
659	struct sched_dl_entity *pi_se;
660#endif
661};
662
663#ifdef CONFIG_UCLAMP_TASK
664/* Number of utilization clamp buckets (shorter alias) */
665#define UCLAMP_BUCKETS CONFIG_UCLAMP_BUCKETS_COUNT
666
667/*
668 * Utilization clamp for a scheduling entity
669 * @value:		clamp value "assigned" to a se
670 * @bucket_id:		bucket index corresponding to the "assigned" value
671 * @active:		the se is currently refcounted in a rq's bucket
672 * @user_defined:	the requested clamp value comes from user-space
673 *
674 * The bucket_id is the index of the clamp bucket matching the clamp value
675 * which is pre-computed and stored to avoid expensive integer divisions from
676 * the fast path.
677 *
678 * The active bit is set whenever a task has got an "effective" value assigned,
679 * which can be different from the clamp value "requested" from user-space.
680 * This allows to know a task is refcounted in the rq's bucket corresponding
681 * to the "effective" bucket_id.
682 *
683 * The user_defined bit is set whenever a task has got a task-specific clamp
684 * value requested from userspace, i.e. the system defaults apply to this task
685 * just as a restriction. This allows to relax default clamps when a less
686 * restrictive task-specific value has been requested, thus allowing to
687 * implement a "nice" semantic. For example, a task running with a 20%
688 * default boost can still drop its own boosting to 0%.
689 */
690struct uclamp_se {
691	unsigned int value		: bits_per(SCHED_CAPACITY_SCALE);
692	unsigned int bucket_id		: bits_per(UCLAMP_BUCKETS);
693	unsigned int active		: 1;
694	unsigned int user_defined	: 1;
695};
696#endif /* CONFIG_UCLAMP_TASK */
697
698union rcu_special {
699	struct {
700		u8			blocked;
701		u8			need_qs;
702		u8			exp_hint; /* Hint for performance. */
703		u8			need_mb; /* Readers need smp_mb(). */
704	} b; /* Bits. */
705	u32 s; /* Set of bits. */
706};
707
708enum perf_event_task_context {
709	perf_invalid_context = -1,
710	perf_hw_context = 0,
711	perf_sw_context,
712	perf_nr_task_contexts,
713};
714
715struct wake_q_node {
716	struct wake_q_node *next;
717};
718
719struct kmap_ctrl {
720#ifdef CONFIG_KMAP_LOCAL
721	int				idx;
722	pte_t				pteval[KM_MAX_IDX];
723#endif
724};
725
726struct task_struct {
727#ifdef CONFIG_THREAD_INFO_IN_TASK
728	/*
729	 * For reasons of header soup (see current_thread_info()), this
730	 * must be the first element of task_struct.
731	 */
732	struct thread_info		thread_info;
733#endif
734	unsigned int			__state;
735
736#ifdef CONFIG_PREEMPT_RT
737	/* saved state for "spinlock sleepers" */
738	unsigned int			saved_state;
739#endif
740
741	/*
742	 * This begins the randomizable portion of task_struct. Only
743	 * scheduling-critical items should be added above here.
744	 */
745	randomized_struct_fields_start
746
747	void				*stack;
748	refcount_t			usage;
749	/* Per task flags (PF_*), defined further below: */
750	unsigned int			flags;
751	unsigned int			ptrace;
752
753#ifdef CONFIG_SMP
754	int				on_cpu;
755	struct __call_single_node	wake_entry;
756	unsigned int			wakee_flips;
757	unsigned long			wakee_flip_decay_ts;
758	struct task_struct		*last_wakee;
759
760	/*
761	 * recent_used_cpu is initially set as the last CPU used by a task
762	 * that wakes affine another task. Waker/wakee relationships can
763	 * push tasks around a CPU where each wakeup moves to the next one.
764	 * Tracking a recently used CPU allows a quick search for a recently
765	 * used CPU that may be idle.
766	 */
767	int				recent_used_cpu;
768	int				wake_cpu;
769#endif
770	int				on_rq;
771
772	int				prio;
773	int				static_prio;
774	int				normal_prio;
775	unsigned int			rt_priority;
776
777	struct sched_entity		se;
778	struct sched_rt_entity		rt;
779	struct sched_dl_entity		dl;
780	const struct sched_class	*sched_class;
781
782#ifdef CONFIG_SCHED_CORE
783	struct rb_node			core_node;
784	unsigned long			core_cookie;
785	unsigned int			core_occupation;
786#endif
787
788#ifdef CONFIG_CGROUP_SCHED
789	struct task_group		*sched_task_group;
790#endif
791
792#ifdef CONFIG_UCLAMP_TASK
793	/*
794	 * Clamp values requested for a scheduling entity.
795	 * Must be updated with task_rq_lock() held.
796	 */
797	struct uclamp_se		uclamp_req[UCLAMP_CNT];
798	/*
799	 * Effective clamp values used for a scheduling entity.
800	 * Must be updated with task_rq_lock() held.
801	 */
802	struct uclamp_se		uclamp[UCLAMP_CNT];
803#endif
804
805	struct sched_statistics         stats;
806
807#ifdef CONFIG_PREEMPT_NOTIFIERS
808	/* List of struct preempt_notifier: */
809	struct hlist_head		preempt_notifiers;
810#endif
811
812#ifdef CONFIG_BLK_DEV_IO_TRACE
813	unsigned int			btrace_seq;
814#endif
815
816	unsigned int			policy;
817	int				nr_cpus_allowed;
818	const cpumask_t			*cpus_ptr;
819	cpumask_t			*user_cpus_ptr;
820	cpumask_t			cpus_mask;
821	void				*migration_pending;
822#ifdef CONFIG_SMP
823	unsigned short			migration_disabled;
824#endif
825	unsigned short			migration_flags;
826
827#ifdef CONFIG_PREEMPT_RCU
828	int				rcu_read_lock_nesting;
829	union rcu_special		rcu_read_unlock_special;
830	struct list_head		rcu_node_entry;
831	struct rcu_node			*rcu_blocked_node;
832#endif /* #ifdef CONFIG_PREEMPT_RCU */
833
834#ifdef CONFIG_TASKS_RCU
835	unsigned long			rcu_tasks_nvcsw;
836	u8				rcu_tasks_holdout;
837	u8				rcu_tasks_idx;
838	int				rcu_tasks_idle_cpu;
839	struct list_head		rcu_tasks_holdout_list;
840#endif /* #ifdef CONFIG_TASKS_RCU */
841
842#ifdef CONFIG_TASKS_TRACE_RCU
843	int				trc_reader_nesting;
844	int				trc_ipi_to_cpu;
845	union rcu_special		trc_reader_special;
846	bool				trc_reader_checked;
847	struct list_head		trc_holdout_list;
848#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
849
850	struct sched_info		sched_info;
851
852	struct list_head		tasks;
853#ifdef CONFIG_SMP
854	struct plist_node		pushable_tasks;
855	struct rb_node			pushable_dl_tasks;
856#endif
857
858	struct mm_struct		*mm;
859	struct mm_struct		*active_mm;
860
861	/* Per-thread vma caching: */
862	struct vmacache			vmacache;
863
864#ifdef SPLIT_RSS_COUNTING
865	struct task_rss_stat		rss_stat;
866#endif
867	int				exit_state;
868	int				exit_code;
869	int				exit_signal;
870	/* The signal sent when the parent dies: */
871	int				pdeath_signal;
872	/* JOBCTL_*, siglock protected: */
873	unsigned long			jobctl;
874
875	/* Used for emulating ABI behavior of previous Linux versions: */
876	unsigned int			personality;
877
878	/* Scheduler bits, serialized by scheduler locks: */
879	unsigned			sched_reset_on_fork:1;
880	unsigned			sched_contributes_to_load:1;
881	unsigned			sched_migrated:1;
882#ifdef CONFIG_PSI
883	unsigned			sched_psi_wake_requeue:1;
884#endif
885
886	/* Force alignment to the next boundary: */
887	unsigned			:0;
888
889	/* Unserialized, strictly 'current' */
890
891	/*
892	 * This field must not be in the scheduler word above due to wakelist
893	 * queueing no longer being serialized by p->on_cpu. However:
894	 *
895	 * p->XXX = X;			ttwu()
896	 * schedule()			  if (p->on_rq && ..) // false
897	 *   smp_mb__after_spinlock();	  if (smp_load_acquire(&p->on_cpu) && //true
898	 *   deactivate_task()		      ttwu_queue_wakelist())
899	 *     p->on_rq = 0;			p->sched_remote_wakeup = Y;
900	 *
901	 * guarantees all stores of 'current' are visible before
902	 * ->sched_remote_wakeup gets used, so it can be in this word.
903	 */
904	unsigned			sched_remote_wakeup:1;
905
906	/* Bit to tell LSMs we're in execve(): */
907	unsigned			in_execve:1;
908	unsigned			in_iowait:1;
909#ifndef TIF_RESTORE_SIGMASK
910	unsigned			restore_sigmask:1;
911#endif
912#ifdef CONFIG_MEMCG
913	unsigned			in_user_fault:1;
914#endif
915#ifdef CONFIG_COMPAT_BRK
916	unsigned			brk_randomized:1;
917#endif
918#ifdef CONFIG_CGROUPS
919	/* disallow userland-initiated cgroup migration */
920	unsigned			no_cgroup_migration:1;
921	/* task is frozen/stopped (used by the cgroup freezer) */
922	unsigned			frozen:1;
923#endif
924#ifdef CONFIG_BLK_CGROUP
925	unsigned			use_memdelay:1;
926#endif
927#ifdef CONFIG_PSI
928	/* Stalled due to lack of memory */
929	unsigned			in_memstall:1;
930#endif
931#ifdef CONFIG_PAGE_OWNER
932	/* Used by page_owner=on to detect recursion in page tracking. */
933	unsigned			in_page_owner:1;
934#endif
935#ifdef CONFIG_EVENTFD
936	/* Recursion prevention for eventfd_signal() */
937	unsigned			in_eventfd_signal:1;
938#endif
939#ifdef CONFIG_IOMMU_SVA
940	unsigned			pasid_activated:1;
941#endif
942#ifdef	CONFIG_CPU_SUP_INTEL
943	unsigned			reported_split_lock:1;
944#endif
945
946	unsigned long			atomic_flags; /* Flags requiring atomic access. */
947
948	struct restart_block		restart_block;
949
950	pid_t				pid;
951	pid_t				tgid;
952
953#ifdef CONFIG_STACKPROTECTOR
954	/* Canary value for the -fstack-protector GCC feature: */
955	unsigned long			stack_canary;
956#endif
957	/*
958	 * Pointers to the (original) parent process, youngest child, younger sibling,
959	 * older sibling, respectively.  (p->father can be replaced with
960	 * p->real_parent->pid)
961	 */
962
963	/* Real parent process: */
964	struct task_struct __rcu	*real_parent;
965
966	/* Recipient of SIGCHLD, wait4() reports: */
967	struct task_struct __rcu	*parent;
968
969	/*
970	 * Children/sibling form the list of natural children:
971	 */
972	struct list_head		children;
973	struct list_head		sibling;
974	struct task_struct		*group_leader;
975
976	/*
977	 * 'ptraced' is the list of tasks this task is using ptrace() on.
978	 *
979	 * This includes both natural children and PTRACE_ATTACH targets.
980	 * 'ptrace_entry' is this task's link on the p->parent->ptraced list.
981	 */
982	struct list_head		ptraced;
983	struct list_head		ptrace_entry;
984
985	/* PID/PID hash table linkage. */
986	struct pid			*thread_pid;
987	struct hlist_node		pid_links[PIDTYPE_MAX];
988	struct list_head		thread_group;
989	struct list_head		thread_node;
990
991	struct completion		*vfork_done;
992
993	/* CLONE_CHILD_SETTID: */
994	int __user			*set_child_tid;
995
996	/* CLONE_CHILD_CLEARTID: */
997	int __user			*clear_child_tid;
998
999	/* PF_KTHREAD | PF_IO_WORKER */
1000	void				*worker_private;
1001
1002	u64				utime;
1003	u64				stime;
1004#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
1005	u64				utimescaled;
1006	u64				stimescaled;
1007#endif
1008	u64				gtime;
1009	struct prev_cputime		prev_cputime;
1010#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1011	struct vtime			vtime;
1012#endif
1013
1014#ifdef CONFIG_NO_HZ_FULL
1015	atomic_t			tick_dep_mask;
1016#endif
1017	/* Context switch counts: */
1018	unsigned long			nvcsw;
1019	unsigned long			nivcsw;
1020
1021	/* Monotonic time in nsecs: */
1022	u64				start_time;
1023
1024	/* Boot based time in nsecs: */
1025	u64				start_boottime;
1026
1027	/* MM fault and swap info: this can arguably be seen as either mm-specific or thread-specific: */
1028	unsigned long			min_flt;
1029	unsigned long			maj_flt;
1030
1031	/* Empty if CONFIG_POSIX_CPUTIMERS=n */
1032	struct posix_cputimers		posix_cputimers;
1033
1034#ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
1035	struct posix_cputimers_work	posix_cputimers_work;
1036#endif
1037
1038	/* Process credentials: */
1039
1040	/* Tracer's credentials at attach: */
1041	const struct cred __rcu		*ptracer_cred;
1042
1043	/* Objective and real subjective task credentials (COW): */
1044	const struct cred __rcu		*real_cred;
1045
1046	/* Effective (overridable) subjective task credentials (COW): */
1047	const struct cred __rcu		*cred;
1048
1049#ifdef CONFIG_KEYS
1050	/* Cached requested key. */
1051	struct key			*cached_requested_key;
1052#endif
1053
1054	/*
1055	 * executable name, excluding path.
1056	 *
1057	 * - normally initialized setup_new_exec()
1058	 * - access it with [gs]et_task_comm()
1059	 * - lock it with task_lock()
1060	 */
1061	char				comm[TASK_COMM_LEN];
1062
1063	struct nameidata		*nameidata;
1064
1065#ifdef CONFIG_SYSVIPC
1066	struct sysv_sem			sysvsem;
1067	struct sysv_shm			sysvshm;
1068#endif
1069#ifdef CONFIG_DETECT_HUNG_TASK
1070	unsigned long			last_switch_count;
1071	unsigned long			last_switch_time;
1072#endif
1073	/* Filesystem information: */
1074	struct fs_struct		*fs;
1075
1076	/* Open file information: */
1077	struct files_struct		*files;
1078
1079#ifdef CONFIG_IO_URING
1080	struct io_uring_task		*io_uring;
1081#endif
1082
1083	/* Namespaces: */
1084	struct nsproxy			*nsproxy;
1085
1086	/* Signal handlers: */
1087	struct signal_struct		*signal;
1088	struct sighand_struct __rcu		*sighand;
1089	sigset_t			blocked;
1090	sigset_t			real_blocked;
1091	/* Restored if set_restore_sigmask() was used: */
1092	sigset_t			saved_sigmask;
1093	struct sigpending		pending;
1094	unsigned long			sas_ss_sp;
1095	size_t				sas_ss_size;
1096	unsigned int			sas_ss_flags;
1097
1098	struct callback_head		*task_works;
1099
1100#ifdef CONFIG_AUDIT
1101#ifdef CONFIG_AUDITSYSCALL
1102	struct audit_context		*audit_context;
1103#endif
1104	kuid_t				loginuid;
1105	unsigned int			sessionid;
1106#endif
1107	struct seccomp			seccomp;
1108	struct syscall_user_dispatch	syscall_dispatch;
1109
1110	/* Thread group tracking: */
1111	u64				parent_exec_id;
1112	u64				self_exec_id;
1113
1114	/* Protection against (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed, mempolicy: */
1115	spinlock_t			alloc_lock;
1116
1117	/* Protection of the PI data structures: */
1118	raw_spinlock_t			pi_lock;
1119
1120	struct wake_q_node		wake_q;
1121
1122#ifdef CONFIG_RT_MUTEXES
1123	/* PI waiters blocked on a rt_mutex held by this task: */
1124	struct rb_root_cached		pi_waiters;
1125	/* Updated under owner's pi_lock and rq lock */
1126	struct task_struct		*pi_top_task;
1127	/* Deadlock detection and priority inheritance handling: */
1128	struct rt_mutex_waiter		*pi_blocked_on;
1129#endif
1130
1131#ifdef CONFIG_DEBUG_MUTEXES
1132	/* Mutex deadlock detection: */
1133	struct mutex_waiter		*blocked_on;
1134#endif
1135
1136#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1137	int				non_block_count;
1138#endif
1139
1140#ifdef CONFIG_TRACE_IRQFLAGS
1141	struct irqtrace_events		irqtrace;
1142	unsigned int			hardirq_threaded;
1143	u64				hardirq_chain_key;
1144	int				softirqs_enabled;
1145	int				softirq_context;
1146	int				irq_config;
1147#endif
1148#ifdef CONFIG_PREEMPT_RT
1149	int				softirq_disable_cnt;
1150#endif
1151
1152#ifdef CONFIG_LOCKDEP
1153# define MAX_LOCK_DEPTH			48UL
1154	u64				curr_chain_key;
1155	int				lockdep_depth;
1156	unsigned int			lockdep_recursion;
1157	struct held_lock		held_locks[MAX_LOCK_DEPTH];
1158#endif
1159
1160#if defined(CONFIG_UBSAN) && !defined(CONFIG_UBSAN_TRAP)
1161	unsigned int			in_ubsan;
1162#endif
1163
1164	/* Journalling filesystem info: */
1165	void				*journal_info;
1166
1167	/* Stacked block device info: */
1168	struct bio_list			*bio_list;
1169
1170	/* Stack plugging: */
1171	struct blk_plug			*plug;
1172
1173	/* VM state: */
1174	struct reclaim_state		*reclaim_state;
1175
1176	struct backing_dev_info		*backing_dev_info;
1177
1178	struct io_context		*io_context;
1179
1180#ifdef CONFIG_COMPACTION
1181	struct capture_control		*capture_control;
1182#endif
1183	/* Ptrace state: */
1184	unsigned long			ptrace_message;
1185	kernel_siginfo_t		*last_siginfo;
1186
1187	struct task_io_accounting	ioac;
1188#ifdef CONFIG_PSI
1189	/* Pressure stall state */
1190	unsigned int			psi_flags;
1191#endif
1192#ifdef CONFIG_TASK_XACCT
1193	/* Accumulated RSS usage: */
1194	u64				acct_rss_mem1;
1195	/* Accumulated virtual memory usage: */
1196	u64				acct_vm_mem1;
1197	/* stime + utime since last update: */
1198	u64				acct_timexpd;
1199#endif
1200#ifdef CONFIG_CPUSETS
1201	/* Protected by ->alloc_lock: */
1202	nodemask_t			mems_allowed;
1203	/* Sequence number to catch updates: */
1204	seqcount_spinlock_t		mems_allowed_seq;
1205	int				cpuset_mem_spread_rotor;
1206	int				cpuset_slab_spread_rotor;
1207#endif
1208#ifdef CONFIG_CGROUPS
1209	/* Control Group info protected by css_set_lock: */
1210	struct css_set __rcu		*cgroups;
1211	/* cg_list protected by css_set_lock and tsk->alloc_lock: */
1212	struct list_head		cg_list;
1213#endif
1214#ifdef CONFIG_X86_CPU_RESCTRL
1215	u32				closid;
1216	u32				rmid;
1217#endif
1218#ifdef CONFIG_FUTEX
1219	struct robust_list_head __user	*robust_list;
1220#ifdef CONFIG_COMPAT
1221	struct compat_robust_list_head __user *compat_robust_list;
1222#endif
1223	struct list_head		pi_state_list;
1224	struct futex_pi_state		*pi_state_cache;
1225	struct mutex			futex_exit_mutex;
1226	unsigned int			futex_state;
1227#endif
1228#ifdef CONFIG_PERF_EVENTS
1229	struct perf_event_context	*perf_event_ctxp[perf_nr_task_contexts];
1230	struct mutex			perf_event_mutex;
1231	struct list_head		perf_event_list;
1232#endif
1233#ifdef CONFIG_DEBUG_PREEMPT
1234	unsigned long			preempt_disable_ip;
1235#endif
1236#ifdef CONFIG_NUMA
1237	/* Protected by alloc_lock: */
1238	struct mempolicy		*mempolicy;
1239	short				il_prev;
1240	short				pref_node_fork;
1241#endif
1242#ifdef CONFIG_NUMA_BALANCING
1243	int				numa_scan_seq;
1244	unsigned int			numa_scan_period;
1245	unsigned int			numa_scan_period_max;
1246	int				numa_preferred_nid;
1247	unsigned long			numa_migrate_retry;
1248	/* Migration stamp: */
1249	u64				node_stamp;
1250	u64				last_task_numa_placement;
1251	u64				last_sum_exec_runtime;
1252	struct callback_head		numa_work;
1253
1254	/*
1255	 * This pointer is only modified for current in syscall and
1256	 * pagefault context (and for tasks being destroyed), so it can be read
1257	 * from any of the following contexts:
1258	 *  - RCU read-side critical section
1259	 *  - current->numa_group from everywhere
1260	 *  - task's runqueue locked, task not running
1261	 */
1262	struct numa_group __rcu		*numa_group;
1263
1264	/*
1265	 * numa_faults is an array split into four regions:
1266	 * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
1267	 * in this precise order.
1268	 *
1269	 * faults_memory: Exponential decaying average of faults on a per-node
1270	 * basis. Scheduling placement decisions are made based on these
1271	 * counts. The values remain static for the duration of a PTE scan.
1272	 * faults_cpu: Track the nodes the process was running on when a NUMA
1273	 * hinting fault was incurred.
1274	 * faults_memory_buffer and faults_cpu_buffer: Record faults per node
1275	 * during the current scan window. When the scan completes, the counts
1276	 * in faults_memory and faults_cpu decay and these values are copied.
1277	 */
1278	unsigned long			*numa_faults;
1279	unsigned long			total_numa_faults;
1280
1281	/*
1282	 * numa_faults_locality tracks if faults recorded during the last
1283	 * scan window were remote/local or failed to migrate. The task scan
1284	 * period is adapted based on the locality of the faults with different
1285	 * weights depending on whether they were shared or private faults
1286	 */
1287	unsigned long			numa_faults_locality[3];
1288
1289	unsigned long			numa_pages_migrated;
1290#endif /* CONFIG_NUMA_BALANCING */
1291
1292#ifdef CONFIG_RSEQ
1293	struct rseq __user *rseq;
1294	u32 rseq_sig;
1295	/*
1296	 * RmW on rseq_event_mask must be performed atomically
1297	 * with respect to preemption.
1298	 */
1299	unsigned long rseq_event_mask;
1300#endif
1301
1302	struct tlbflush_unmap_batch	tlb_ubc;
1303
1304	union {
1305		refcount_t		rcu_users;
1306		struct rcu_head		rcu;
1307	};
1308
1309	/* Cache last used pipe for splice(): */
1310	struct pipe_inode_info		*splice_pipe;
1311
1312	struct page_frag		task_frag;
1313
1314#ifdef CONFIG_TASK_DELAY_ACCT
1315	struct task_delay_info		*delays;
1316#endif
1317
1318#ifdef CONFIG_FAULT_INJECTION
1319	int				make_it_fail;
1320	unsigned int			fail_nth;
1321#endif
1322	/*
1323	 * When (nr_dirtied >= nr_dirtied_pause), it's time to call
1324	 * balance_dirty_pages() for a dirty throttling pause:
1325	 */
1326	int				nr_dirtied;
1327	int				nr_dirtied_pause;
1328	/* Start of a write-and-pause period: */
1329	unsigned long			dirty_paused_when;
1330
1331#ifdef CONFIG_LATENCYTOP
1332	int				latency_record_count;
1333	struct latency_record		latency_record[LT_SAVECOUNT];
1334#endif
1335	/*
1336	 * Time slack values; these are used to round up poll() and
1337	 * select() etc timeout values. These are in nanoseconds.
1338	 */
1339	u64				timer_slack_ns;
1340	u64				default_timer_slack_ns;
1341
1342#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
1343	unsigned int			kasan_depth;
1344#endif
1345
1346#ifdef CONFIG_KCSAN
1347	struct kcsan_ctx		kcsan_ctx;
1348#ifdef CONFIG_TRACE_IRQFLAGS
1349	struct irqtrace_events		kcsan_save_irqtrace;
1350#endif
1351#ifdef CONFIG_KCSAN_WEAK_MEMORY
1352	int				kcsan_stack_depth;
1353#endif
1354#endif
1355
1356#if IS_ENABLED(CONFIG_KUNIT)
1357	struct kunit			*kunit_test;
1358#endif
1359
1360#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1361	/* Index of current stored address in ret_stack: */
1362	int				curr_ret_stack;
1363	int				curr_ret_depth;
1364
1365	/* Stack of return addresses for return function tracing: */
1366	struct ftrace_ret_stack		*ret_stack;
1367
1368	/* Timestamp for last schedule: */
1369	unsigned long long		ftrace_timestamp;
1370
1371	/*
1372	 * Number of functions that haven't been traced
1373	 * because of depth overrun:
1374	 */
1375	atomic_t			trace_overrun;
1376
1377	/* Pause tracing: */
1378	atomic_t			tracing_graph_pause;
1379#endif
1380
1381#ifdef CONFIG_TRACING
1382	/* State flags for use by tracers: */
1383	unsigned long			trace;
1384
1385	/* Bitmask and counter of trace recursion: */
1386	unsigned long			trace_recursion;
1387#endif /* CONFIG_TRACING */
1388
1389#ifdef CONFIG_KCOV
1390	/* See kernel/kcov.c for more details. */
1391
1392	/* Coverage collection mode enabled for this task (0 if disabled): */
1393	unsigned int			kcov_mode;
1394
1395	/* Size of the kcov_area: */
1396	unsigned int			kcov_size;
1397
1398	/* Buffer for coverage collection: */
1399	void				*kcov_area;
1400
1401	/* KCOV descriptor wired with this task or NULL: */
1402	struct kcov			*kcov;
1403
1404	/* KCOV common handle for remote coverage collection: */
1405	u64				kcov_handle;
1406
1407	/* KCOV sequence number: */
1408	int				kcov_sequence;
1409
1410	/* Collect coverage from softirq context: */
1411	unsigned int			kcov_softirq;
1412#endif
1413
1414#ifdef CONFIG_MEMCG
1415	struct mem_cgroup		*memcg_in_oom;
1416	gfp_t				memcg_oom_gfp_mask;
1417	int				memcg_oom_order;
1418
1419	/* Number of pages to reclaim on returning to userland: */
1420	unsigned int			memcg_nr_pages_over_high;
1421
1422	/* Used by memcontrol for targeted memcg charge: */
1423	struct mem_cgroup		*active_memcg;
1424#endif
1425
1426#ifdef CONFIG_BLK_CGROUP
1427	struct request_queue		*throttle_queue;
1428#endif
1429
1430#ifdef CONFIG_UPROBES
1431	struct uprobe_task		*utask;
1432#endif
1433#if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
1434	unsigned int			sequential_io;
1435	unsigned int			sequential_io_avg;
1436#endif
1437	struct kmap_ctrl		kmap_ctrl;
1438#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1439	unsigned long			task_state_change;
1440# ifdef CONFIG_PREEMPT_RT
1441	unsigned long			saved_state_change;
1442# endif
1443#endif
1444	int				pagefault_disabled;
1445#ifdef CONFIG_MMU
1446	struct task_struct		*oom_reaper_list;
1447	struct timer_list		oom_reaper_timer;
1448#endif
1449#ifdef CONFIG_VMAP_STACK
1450	struct vm_struct		*stack_vm_area;
1451#endif
1452#ifdef CONFIG_THREAD_INFO_IN_TASK
1453	/* A live task holds one reference: */
1454	refcount_t			stack_refcount;
1455#endif
1456#ifdef CONFIG_LIVEPATCH
1457	int patch_state;
1458#endif
1459#ifdef CONFIG_SECURITY
1460	/* Used by LSM modules for access restriction: */
1461	void				*security;
1462#endif
1463#ifdef CONFIG_BPF_SYSCALL
1464	/* Used by BPF task local storage */
1465	struct bpf_local_storage __rcu	*bpf_storage;
1466	/* Used for BPF run context */
1467	struct bpf_run_ctx		*bpf_ctx;
1468#endif
1469
1470#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
1471	unsigned long			lowest_stack;
1472	unsigned long			prev_lowest_stack;
1473#endif
1474
1475#ifdef CONFIG_X86_MCE
1476	void __user			*mce_vaddr;
1477	__u64				mce_kflags;
1478	u64				mce_addr;
1479	__u64				mce_ripv : 1,
1480					mce_whole_page : 1,
1481					__mce_reserved : 62;
1482	struct callback_head		mce_kill_me;
1483	int				mce_count;
1484#endif
1485
1486#ifdef CONFIG_KRETPROBES
1487	struct llist_head               kretprobe_instances;
1488#endif
1489#ifdef CONFIG_RETHOOK
1490	struct llist_head               rethooks;
1491#endif
1492
1493#ifdef CONFIG_ARCH_HAS_PARANOID_L1D_FLUSH
1494	/*
1495	 * If L1D flush is supported on mm context switch
1496	 * then we use this callback head to queue kill work
1497	 * to kill tasks that are not running on SMT disabled
1498	 * cores
1499	 */
1500	struct callback_head		l1d_flush_kill;
1501#endif
1502
1503	/*
1504	 * New fields for task_struct should be added above here, so that
1505	 * they are included in the randomized portion of task_struct.
1506	 */
1507	randomized_struct_fields_end
1508
1509	/* CPU-specific state of this task: */
1510	struct thread_struct		thread;
1511
1512	/*
1513	 * WARNING: on x86, 'thread_struct' contains a variable-sized
1514	 * structure.  It *MUST* be at the end of 'task_struct'.
1515	 *
1516	 * Do not put anything below here!
1517	 */
1518};
1519
1520static inline struct pid *task_pid(struct task_struct *task)
1521{
1522	return task->thread_pid;
1523}
1524
1525/*
1526 * the helpers to get the task's different pids as they are seen
1527 * from various namespaces
1528 *
1529 * task_xid_nr()     : global id, i.e. the id seen from the init namespace;
1530 * task_xid_vnr()    : virtual id, i.e. the id seen from the pid namespace of
1531 *                     current.
1532 * task_xid_nr_ns()  : id seen from the ns specified;
1533 *
1534 * see also pid_nr() etc in include/linux/pid.h
1535 */
1536pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, struct pid_namespace *ns);
1537
1538static inline pid_t task_pid_nr(struct task_struct *tsk)
1539{
1540	return tsk->pid;
1541}
1542
1543static inline pid_t task_pid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1544{
1545	return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1546}
1547
1548static inline pid_t task_pid_vnr(struct task_struct *tsk)
1549{
1550	return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1551}
1552
1553
1554static inline pid_t task_tgid_nr(struct task_struct *tsk)
1555{
1556	return tsk->tgid;
1557}
1558
1559/**
1560 * pid_alive - check that a task structure is not stale
1561 * @p: Task structure to be checked.
1562 *
1563 * Test if a process is not yet dead (at most zombie state)
1564 * If pid_alive fails, then pointers within the task structure
1565 * can be stale and must not be dereferenced.
1566 *
1567 * Return: 1 if the process is alive. 0 otherwise.
1568 */
1569static inline int pid_alive(const struct task_struct *p)
1570{
1571	return p->thread_pid != NULL;
1572}
1573
1574static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1575{
1576	return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1577}
1578
1579static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1580{
1581	return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1582}
1583
1584
1585static inline pid_t task_session_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1586{
1587	return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1588}
1589
1590static inline pid_t task_session_vnr(struct task_struct *tsk)
1591{
1592	return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1593}
1594
1595static inline pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1596{
1597	return __task_pid_nr_ns(tsk, PIDTYPE_TGID, ns);
1598}
1599
1600static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1601{
1602	return __task_pid_nr_ns(tsk, PIDTYPE_TGID, NULL);
1603}
1604
1605static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)
1606{
1607	pid_t pid = 0;
1608
1609	rcu_read_lock();
1610	if (pid_alive(tsk))
1611		pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
1612	rcu_read_unlock();
1613
1614	return pid;
1615}
1616
1617static inline pid_t task_ppid_nr(const struct task_struct *tsk)
1618{
1619	return task_ppid_nr_ns(tsk, &init_pid_ns);
1620}
1621
1622/* Obsolete, do not use: */
1623static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1624{
1625	return task_pgrp_nr_ns(tsk, &init_pid_ns);
1626}
1627
1628#define TASK_REPORT_IDLE	(TASK_REPORT + 1)
1629#define TASK_REPORT_MAX		(TASK_REPORT_IDLE << 1)
1630
1631static inline unsigned int __task_state_index(unsigned int tsk_state,
1632					      unsigned int tsk_exit_state)
1633{
1634	unsigned int state = (tsk_state | tsk_exit_state) & TASK_REPORT;
1635
1636	BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
1637
1638	if (tsk_state == TASK_IDLE)
1639		state = TASK_REPORT_IDLE;
1640
1641	/*
1642	 * We're lying here, but rather than expose a completely new task state
1643	 * to userspace, we can make this appear as if the task has gone through
1644	 * a regular rt_mutex_lock() call.
1645	 */
1646	if (tsk_state == TASK_RTLOCK_WAIT)
1647		state = TASK_UNINTERRUPTIBLE;
1648
1649	return fls(state);
1650}
1651
1652static inline unsigned int task_state_index(struct task_struct *tsk)
1653{
1654	return __task_state_index(READ_ONCE(tsk->__state), tsk->exit_state);
1655}
1656
1657static inline char task_index_to_char(unsigned int state)
1658{
1659	static const char state_char[] = "RSDTtXZPI";
1660
1661	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != sizeof(state_char) - 1);
1662
1663	return state_char[state];
1664}
1665
1666static inline char task_state_to_char(struct task_struct *tsk)
1667{
1668	return task_index_to_char(task_state_index(tsk));
1669}
1670
1671/**
1672 * is_global_init - check if a task structure is init. Since init
1673 * is free to have sub-threads we need to check tgid.
1674 * @tsk: Task structure to be checked.
1675 *
1676 * Check if a task structure is the first user space task the kernel created.
1677 *
1678 * Return: 1 if the task structure is init. 0 otherwise.
1679 */
1680static inline int is_global_init(struct task_struct *tsk)
1681{
1682	return task_tgid_nr(tsk) == 1;
1683}
1684
1685extern struct pid *cad_pid;
1686
1687/*
1688 * Per process flags
1689 */
1690#define PF_VCPU			0x00000001	/* I'm a virtual CPU */
1691#define PF_IDLE			0x00000002	/* I am an IDLE thread */
1692#define PF_EXITING		0x00000004	/* Getting shut down */
1693#define PF_POSTCOREDUMP		0x00000008	/* Coredumps should ignore this task */
1694#define PF_IO_WORKER		0x00000010	/* Task is an IO worker */
1695#define PF_WQ_WORKER		0x00000020	/* I'm a workqueue worker */
1696#define PF_FORKNOEXEC		0x00000040	/* Forked but didn't exec */
1697#define PF_MCE_PROCESS		0x00000080      /* Process policy on mce errors */
1698#define PF_SUPERPRIV		0x00000100	/* Used super-user privileges */
1699#define PF_DUMPCORE		0x00000200	/* Dumped core */
1700#define PF_SIGNALED		0x00000400	/* Killed by a signal */
1701#define PF_MEMALLOC		0x00000800	/* Allocating memory */
1702#define PF_NPROC_EXCEEDED	0x00001000	/* set_user() noticed that RLIMIT_NPROC was exceeded */
1703#define PF_USED_MATH		0x00002000	/* If unset the fpu must be initialized before use */
1704#define PF_NOFREEZE		0x00008000	/* This thread should not be frozen */
1705#define PF_FROZEN		0x00010000	/* Frozen for system suspend */
1706#define PF_KSWAPD		0x00020000	/* I am kswapd */
1707#define PF_MEMALLOC_NOFS	0x00040000	/* All allocation requests will inherit GFP_NOFS */
1708#define PF_MEMALLOC_NOIO	0x00080000	/* All allocation requests will inherit GFP_NOIO */
1709#define PF_LOCAL_THROTTLE	0x00100000	/* Throttle writes only against the bdi I write to,
1710						 * I am cleaning dirty pages from some other bdi. */
1711#define PF_KTHREAD		0x00200000	/* I am a kernel thread */
1712#define PF_RANDOMIZE		0x00400000	/* Randomize virtual address space */
1713#define PF_NO_SETAFFINITY	0x04000000	/* Userland is not allowed to meddle with cpus_mask */
1714#define PF_MCE_EARLY		0x08000000      /* Early kill for mce process policy */
1715#define PF_MEMALLOC_PIN		0x10000000	/* Allocation context constrained to zones which allow long term pinning. */
1716#define PF_FREEZER_SKIP		0x40000000	/* Freezer should not count it as freezable */
1717#define PF_SUSPEND_TASK		0x80000000      /* This thread called freeze_processes() and should not be frozen */
1718
1719/*
1720 * Only the _current_ task can read/write to tsk->flags, but other
1721 * tasks can access tsk->flags in readonly mode for example
1722 * with tsk_used_math (like during threaded core dumping).
1723 * There is however an exception to this rule during ptrace
1724 * or during fork: the ptracer task is allowed to write to the
1725 * child->flags of its traced child (same goes for fork, the parent
1726 * can write to the child->flags), because we're guaranteed the
1727 * child is not running and in turn not changing child->flags
1728 * at the same time the parent does it.
1729 */
1730#define clear_stopped_child_used_math(child)	do { (child)->flags &= ~PF_USED_MATH; } while (0)
1731#define set_stopped_child_used_math(child)	do { (child)->flags |= PF_USED_MATH; } while (0)
1732#define clear_used_math()			clear_stopped_child_used_math(current)
1733#define set_used_math()				set_stopped_child_used_math(current)
1734
1735#define conditional_stopped_child_used_math(condition, child) \
1736	do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1737
1738#define conditional_used_math(condition)	conditional_stopped_child_used_math(condition, current)
1739
1740#define copy_to_stopped_child_used_math(child) \
1741	do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1742
1743/* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1744#define tsk_used_math(p)			((p)->flags & PF_USED_MATH)
1745#define used_math()				tsk_used_math(current)
1746
1747static __always_inline bool is_percpu_thread(void)
1748{
1749#ifdef CONFIG_SMP
1750	return (current->flags & PF_NO_SETAFFINITY) &&
1751		(current->nr_cpus_allowed  == 1);
1752#else
1753	return true;
1754#endif
1755}
1756
1757/* Per-process atomic flags. */
1758#define PFA_NO_NEW_PRIVS		0	/* May not gain new privileges. */
1759#define PFA_SPREAD_PAGE			1	/* Spread page cache over cpuset */
1760#define PFA_SPREAD_SLAB			2	/* Spread some slab caches over cpuset */
1761#define PFA_SPEC_SSB_DISABLE		3	/* Speculative Store Bypass disabled */
1762#define PFA_SPEC_SSB_FORCE_DISABLE	4	/* Speculative Store Bypass force disabled*/
1763#define PFA_SPEC_IB_DISABLE		5	/* Indirect branch speculation restricted */
1764#define PFA_SPEC_IB_FORCE_DISABLE	6	/* Indirect branch speculation permanently restricted */
1765#define PFA_SPEC_SSB_NOEXEC		7	/* Speculative Store Bypass clear on execve() */
1766
1767#define TASK_PFA_TEST(name, func)					\
1768	static inline bool task_##func(struct task_struct *p)		\
1769	{ return test_bit(PFA_##name, &p->atomic_flags); }
1770
1771#define TASK_PFA_SET(name, func)					\
1772	static inline void task_set_##func(struct task_struct *p)	\
1773	{ set_bit(PFA_##name, &p->atomic_flags); }
1774
1775#define TASK_PFA_CLEAR(name, func)					\
1776	static inline void task_clear_##func(struct task_struct *p)	\
1777	{ clear_bit(PFA_##name, &p->atomic_flags); }
1778
1779TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
1780TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
1781
1782TASK_PFA_TEST(SPREAD_PAGE, spread_page)
1783TASK_PFA_SET(SPREAD_PAGE, spread_page)
1784TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
1785
1786TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
1787TASK_PFA_SET(SPREAD_SLAB, spread_slab)
1788TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
1789
1790TASK_PFA_TEST(SPEC_SSB_DISABLE, spec_ssb_disable)
1791TASK_PFA_SET(SPEC_SSB_DISABLE, spec_ssb_disable)
1792TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
1793
1794TASK_PFA_TEST(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1795TASK_PFA_SET(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1796TASK_PFA_CLEAR(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1797
1798TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
1799TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
1800
1801TASK_PFA_TEST(SPEC_IB_DISABLE, spec_ib_disable)
1802TASK_PFA_SET(SPEC_IB_DISABLE, spec_ib_disable)
1803TASK_PFA_CLEAR(SPEC_IB_DISABLE, spec_ib_disable)
1804
1805TASK_PFA_TEST(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
1806TASK_PFA_SET(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
1807
1808static inline void
1809current_restore_flags(unsigned long orig_flags, unsigned long flags)
1810{
1811	current->flags &= ~flags;
1812	current->flags |= orig_flags & flags;
1813}
1814
1815extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
1816extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
1817#ifdef CONFIG_SMP
1818extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
1819extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);
1820extern int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node);
1821extern void release_user_cpus_ptr(struct task_struct *p);
1822extern int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask);
1823extern void force_compatible_cpus_allowed_ptr(struct task_struct *p);
1824extern void relax_compatible_cpus_allowed_ptr(struct task_struct *p);
1825#else
1826static inline void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
1827{
1828}
1829static inline int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1830{
1831	if (!cpumask_test_cpu(0, new_mask))
1832		return -EINVAL;
1833	return 0;
1834}
1835static inline int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node)
1836{
1837	if (src->user_cpus_ptr)
1838		return -EINVAL;
1839	return 0;
1840}
1841static inline void release_user_cpus_ptr(struct task_struct *p)
1842{
1843	WARN_ON(p->user_cpus_ptr);
1844}
1845
1846static inline int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
1847{
1848	return 0;
1849}
1850#endif
1851
1852extern int yield_to(struct task_struct *p, bool preempt);
1853extern void set_user_nice(struct task_struct *p, long nice);
1854extern int task_prio(const struct task_struct *p);
1855
1856/**
1857 * task_nice - return the nice value of a given task.
1858 * @p: the task in question.
1859 *
1860 * Return: The nice value [ -20 ... 0 ... 19 ].
1861 */
1862static inline int task_nice(const struct task_struct *p)
1863{
1864	return PRIO_TO_NICE((p)->static_prio);
1865}
1866
1867extern int can_nice(const struct task_struct *p, const int nice);
1868extern int task_curr(const struct task_struct *p);
1869extern int idle_cpu(int cpu);
1870extern int available_idle_cpu(int cpu);
1871extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *);
1872extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *);
1873extern void sched_set_fifo(struct task_struct *p);
1874extern void sched_set_fifo_low(struct task_struct *p);
1875extern void sched_set_normal(struct task_struct *p, int nice);
1876extern int sched_setattr(struct task_struct *, const struct sched_attr *);
1877extern int sched_setattr_nocheck(struct task_struct *, const struct sched_attr *);
1878extern struct task_struct *idle_task(int cpu);
1879
1880/**
1881 * is_idle_task - is the specified task an idle task?
1882 * @p: the task in question.
1883 *
1884 * Return: 1 if @p is an idle task. 0 otherwise.
1885 */
1886static __always_inline bool is_idle_task(const struct task_struct *p)
1887{
1888	return !!(p->flags & PF_IDLE);
1889}
1890
1891extern struct task_struct *curr_task(int cpu);
1892extern void ia64_set_curr_task(int cpu, struct task_struct *p);
1893
1894void yield(void);
1895
1896union thread_union {
1897#ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK
1898	struct task_struct task;
1899#endif
1900#ifndef CONFIG_THREAD_INFO_IN_TASK
1901	struct thread_info thread_info;
1902#endif
1903	unsigned long stack[THREAD_SIZE/sizeof(long)];
1904};
1905
1906#ifndef CONFIG_THREAD_INFO_IN_TASK
1907extern struct thread_info init_thread_info;
1908#endif
1909
1910extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)];
1911
1912#ifdef CONFIG_THREAD_INFO_IN_TASK
1913# define task_thread_info(task)	(&(task)->thread_info)
1914#elif !defined(__HAVE_THREAD_FUNCTIONS)
1915# define task_thread_info(task)	((struct thread_info *)(task)->stack)
1916#endif
1917
1918/*
1919 * find a task by one of its numerical ids
1920 *
1921 * find_task_by_pid_ns():
1922 *      finds a task by its pid in the specified namespace
1923 * find_task_by_vpid():
1924 *      finds a task by its virtual pid
1925 *
1926 * see also find_vpid() etc in include/linux/pid.h
1927 */
1928
1929extern struct task_struct *find_task_by_vpid(pid_t nr);
1930extern struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns);
1931
1932/*
1933 * find a task by its virtual pid and get the task struct
1934 */
1935extern struct task_struct *find_get_task_by_vpid(pid_t nr);
1936
1937extern int wake_up_state(struct task_struct *tsk, unsigned int state);
1938extern int wake_up_process(struct task_struct *tsk);
1939extern void wake_up_new_task(struct task_struct *tsk);
1940
1941#ifdef CONFIG_SMP
1942extern void kick_process(struct task_struct *tsk);
1943#else
1944static inline void kick_process(struct task_struct *tsk) { }
1945#endif
1946
1947extern void __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
1948
1949static inline void set_task_comm(struct task_struct *tsk, const char *from)
1950{
1951	__set_task_comm(tsk, from, false);
1952}
1953
1954extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
1955#define get_task_comm(buf, tsk) ({			\
1956	BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN);	\
1957	__get_task_comm(buf, sizeof(buf), tsk);		\
1958})
1959
1960#ifdef CONFIG_SMP
1961static __always_inline void scheduler_ipi(void)
1962{
1963	/*
1964	 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1965	 * TIF_NEED_RESCHED remotely (for the first time) will also send
1966	 * this IPI.
1967	 */
1968	preempt_fold_need_resched();
1969}
1970extern unsigned long wait_task_inactive(struct task_struct *, unsigned int match_state);
1971#else
1972static inline void scheduler_ipi(void) { }
1973static inline unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
1974{
1975	return 1;
1976}
1977#endif
1978
1979/*
1980 * Set thread flags in other task's structures.
1981 * See asm/thread_info.h for TIF_xxxx flags available:
1982 */
1983static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
1984{
1985	set_ti_thread_flag(task_thread_info(tsk), flag);
1986}
1987
1988static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1989{
1990	clear_ti_thread_flag(task_thread_info(tsk), flag);
1991}
1992
1993static inline void update_tsk_thread_flag(struct task_struct *tsk, int flag,
1994					  bool value)
1995{
1996	update_ti_thread_flag(task_thread_info(tsk), flag, value);
1997}
1998
1999static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
2000{
2001	return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
2002}
2003
2004static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2005{
2006	return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
2007}
2008
2009static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
2010{
2011	return test_ti_thread_flag(task_thread_info(tsk), flag);
2012}
2013
2014static inline void set_tsk_need_resched(struct task_struct *tsk)
2015{
2016	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2017}
2018
2019static inline void clear_tsk_need_resched(struct task_struct *tsk)
2020{
2021	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2022}
2023
2024static inline int test_tsk_need_resched(struct task_struct *tsk)
2025{
2026	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
2027}
2028
2029/*
2030 * cond_resched() and cond_resched_lock(): latency reduction via
2031 * explicit rescheduling in places that are safe. The return
2032 * value indicates whether a reschedule was done in fact.
2033 * cond_resched_lock() will drop the spinlock before scheduling,
2034 */
2035#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
2036extern int __cond_resched(void);
2037
2038#if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
2039
2040DECLARE_STATIC_CALL(cond_resched, __cond_resched);
2041
2042static __always_inline int _cond_resched(void)
2043{
2044	return static_call_mod(cond_resched)();
2045}
2046
2047#elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
2048extern int dynamic_cond_resched(void);
2049
2050static __always_inline int _cond_resched(void)
2051{
2052	return dynamic_cond_resched();
2053}
2054
2055#else
2056
2057static inline int _cond_resched(void)
2058{
2059	return __cond_resched();
2060}
2061
2062#endif /* CONFIG_PREEMPT_DYNAMIC */
2063
2064#else
2065
2066static inline int _cond_resched(void) { return 0; }
2067
2068#endif /* !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) */
2069
2070#define cond_resched() ({			\
2071	__might_resched(__FILE__, __LINE__, 0);	\
2072	_cond_resched();			\
2073})
2074
2075extern int __cond_resched_lock(spinlock_t *lock);
2076extern int __cond_resched_rwlock_read(rwlock_t *lock);
2077extern int __cond_resched_rwlock_write(rwlock_t *lock);
2078
2079#define MIGHT_RESCHED_RCU_SHIFT		8
2080#define MIGHT_RESCHED_PREEMPT_MASK	((1U << MIGHT_RESCHED_RCU_SHIFT) - 1)
2081
2082#ifndef CONFIG_PREEMPT_RT
2083/*
2084 * Non RT kernels have an elevated preempt count due to the held lock,
2085 * but are not allowed to be inside a RCU read side critical section
2086 */
2087# define PREEMPT_LOCK_RESCHED_OFFSETS	PREEMPT_LOCK_OFFSET
2088#else
2089/*
2090 * spin/rw_lock() on RT implies rcu_read_lock(). The might_sleep() check in
2091 * cond_resched*lock() has to take that into account because it checks for
2092 * preempt_count() and rcu_preempt_depth().
2093 */
2094# define PREEMPT_LOCK_RESCHED_OFFSETS	\
2095	(PREEMPT_LOCK_OFFSET + (1U << MIGHT_RESCHED_RCU_SHIFT))
2096#endif
2097
2098#define cond_resched_lock(lock) ({						\
2099	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);	\
2100	__cond_resched_lock(lock);						\
2101})
2102
2103#define cond_resched_rwlock_read(lock) ({					\
2104	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);	\
2105	__cond_resched_rwlock_read(lock);					\
2106})
2107
2108#define cond_resched_rwlock_write(lock) ({					\
2109	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);	\
2110	__cond_resched_rwlock_write(lock);					\
2111})
2112
2113static inline void cond_resched_rcu(void)
2114{
2115#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
2116	rcu_read_unlock();
2117	cond_resched();
2118	rcu_read_lock();
2119#endif
2120}
2121
2122#ifdef CONFIG_PREEMPT_DYNAMIC
2123
2124extern bool preempt_model_none(void);
2125extern bool preempt_model_voluntary(void);
2126extern bool preempt_model_full(void);
2127
2128#else
2129
2130static inline bool preempt_model_none(void)
2131{
2132	return IS_ENABLED(CONFIG_PREEMPT_NONE);
2133}
2134static inline bool preempt_model_voluntary(void)
2135{
2136	return IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY);
2137}
2138static inline bool preempt_model_full(void)
2139{
2140	return IS_ENABLED(CONFIG_PREEMPT);
2141}
2142
2143#endif
2144
2145static inline bool preempt_model_rt(void)
2146{
2147	return IS_ENABLED(CONFIG_PREEMPT_RT);
2148}
2149
2150/*
2151 * Does the preemption model allow non-cooperative preemption?
2152 *
2153 * For !CONFIG_PREEMPT_DYNAMIC kernels this is an exact match with
2154 * CONFIG_PREEMPTION; for CONFIG_PREEMPT_DYNAMIC this doesn't work as the
2155 * kernel is *built* with CONFIG_PREEMPTION=y but may run with e.g. the
2156 * PREEMPT_NONE model.
2157 */
2158static inline bool preempt_model_preemptible(void)
2159{
2160	return preempt_model_full() || preempt_model_rt();
2161}
2162
2163/*
2164 * Does a critical section need to be broken due to another
2165 * task waiting?: (technically does not depend on CONFIG_PREEMPTION,
2166 * but a general need for low latency)
2167 */
2168static inline int spin_needbreak(spinlock_t *lock)
2169{
2170#ifdef CONFIG_PREEMPTION
2171	return spin_is_contended(lock);
2172#else
2173	return 0;
2174#endif
2175}
2176
2177/*
2178 * Check if a rwlock is contended.
2179 * Returns non-zero if there is another task waiting on the rwlock.
2180 * Returns zero if the lock is not contended or the system / underlying
2181 * rwlock implementation does not support contention detection.
2182 * Technically does not depend on CONFIG_PREEMPTION, but a general need
2183 * for low latency.
2184 */
2185static inline int rwlock_needbreak(rwlock_t *lock)
2186{
2187#ifdef CONFIG_PREEMPTION
2188	return rwlock_is_contended(lock);
2189#else
2190	return 0;
2191#endif
2192}
2193
2194static __always_inline bool need_resched(void)
2195{
2196	return unlikely(tif_need_resched());
2197}
2198
2199/*
2200 * Wrappers for p->thread_info->cpu access. No-op on UP.
2201 */
2202#ifdef CONFIG_SMP
2203
2204static inline unsigned int task_cpu(const struct task_struct *p)
2205{
2206	return READ_ONCE(task_thread_info(p)->cpu);
2207}
2208
2209extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
2210
2211#else
2212
2213static inline unsigned int task_cpu(const struct task_struct *p)
2214{
2215	return 0;
2216}
2217
2218static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
2219{
2220}
2221
2222#endif /* CONFIG_SMP */
2223
2224extern bool sched_task_on_rq(struct task_struct *p);
2225extern unsigned long get_wchan(struct task_struct *p);
2226
2227/*
2228 * In order to reduce various lock holder preemption latencies provide an
2229 * interface to see if a vCPU is currently running or not.
2230 *
2231 * This allows us to terminate optimistic spin loops and block, analogous to
2232 * the native optimistic spin heuristic of testing if the lock owner task is
2233 * running or not.
2234 */
2235#ifndef vcpu_is_preempted
2236static inline bool vcpu_is_preempted(int cpu)
2237{
2238	return false;
2239}
2240#endif
2241
2242extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
2243extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
2244
2245#ifndef TASK_SIZE_OF
2246#define TASK_SIZE_OF(tsk)	TASK_SIZE
2247#endif
2248
2249#ifdef CONFIG_SMP
2250static inline bool owner_on_cpu(struct task_struct *owner)
2251{
2252	/*
2253	 * As lock holder preemption issue, we both skip spinning if
2254	 * task is not on cpu or its cpu is preempted
2255	 */
2256	return READ_ONCE(owner->on_cpu) && !vcpu_is_preempted(task_cpu(owner));
2257}
2258
2259/* Returns effective CPU energy utilization, as seen by the scheduler */
2260unsigned long sched_cpu_util(int cpu, unsigned long max);
2261#endif /* CONFIG_SMP */
2262
2263#ifdef CONFIG_RSEQ
2264
2265/*
2266 * Map the event mask on the user-space ABI enum rseq_cs_flags
2267 * for direct mask checks.
2268 */
2269enum rseq_event_mask_bits {
2270	RSEQ_EVENT_PREEMPT_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
2271	RSEQ_EVENT_SIGNAL_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
2272	RSEQ_EVENT_MIGRATE_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
2273};
2274
2275enum rseq_event_mask {
2276	RSEQ_EVENT_PREEMPT	= (1U << RSEQ_EVENT_PREEMPT_BIT),
2277	RSEQ_EVENT_SIGNAL	= (1U << RSEQ_EVENT_SIGNAL_BIT),
2278	RSEQ_EVENT_MIGRATE	= (1U << RSEQ_EVENT_MIGRATE_BIT),
2279};
2280
2281static inline void rseq_set_notify_resume(struct task_struct *t)
2282{
2283	if (t->rseq)
2284		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
2285}
2286
2287void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
2288
2289static inline void rseq_handle_notify_resume(struct ksignal *ksig,
2290					     struct pt_regs *regs)
2291{
2292	if (current->rseq)
2293		__rseq_handle_notify_resume(ksig, regs);
2294}
2295
2296static inline void rseq_signal_deliver(struct ksignal *ksig,
2297				       struct pt_regs *regs)
2298{
2299	preempt_disable();
2300	__set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
2301	preempt_enable();
2302	rseq_handle_notify_resume(ksig, regs);
2303}
2304
2305/* rseq_preempt() requires preemption to be disabled. */
2306static inline void rseq_preempt(struct task_struct *t)
2307{
2308	__set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
2309	rseq_set_notify_resume(t);
2310}
2311
2312/* rseq_migrate() requires preemption to be disabled. */
2313static inline void rseq_migrate(struct task_struct *t)
2314{
2315	__set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
2316	rseq_set_notify_resume(t);
2317}
2318
2319/*
2320 * If parent process has a registered restartable sequences area, the
2321 * child inherits. Unregister rseq for a clone with CLONE_VM set.
2322 */
2323static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
2324{
2325	if (clone_flags & CLONE_VM) {
2326		t->rseq = NULL;
2327		t->rseq_sig = 0;
2328		t->rseq_event_mask = 0;
2329	} else {
2330		t->rseq = current->rseq;
2331		t->rseq_sig = current->rseq_sig;
2332		t->rseq_event_mask = current->rseq_event_mask;
2333	}
2334}
2335
2336static inline void rseq_execve(struct task_struct *t)
2337{
2338	t->rseq = NULL;
2339	t->rseq_sig = 0;
2340	t->rseq_event_mask = 0;
2341}
2342
2343#else
2344
2345static inline void rseq_set_notify_resume(struct task_struct *t)
2346{
2347}
2348static inline void rseq_handle_notify_resume(struct ksignal *ksig,
2349					     struct pt_regs *regs)
2350{
2351}
2352static inline void rseq_signal_deliver(struct ksignal *ksig,
2353				       struct pt_regs *regs)
2354{
2355}
2356static inline void rseq_preempt(struct task_struct *t)
2357{
2358}
2359static inline void rseq_migrate(struct task_struct *t)
2360{
2361}
2362static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
2363{
2364}
2365static inline void rseq_execve(struct task_struct *t)
2366{
2367}
2368
2369#endif
2370
2371#ifdef CONFIG_DEBUG_RSEQ
2372
2373void rseq_syscall(struct pt_regs *regs);
2374
2375#else
2376
2377static inline void rseq_syscall(struct pt_regs *regs)
2378{
2379}
2380
2381#endif
2382
2383#ifdef CONFIG_SCHED_CORE
2384extern void sched_core_free(struct task_struct *tsk);
2385extern void sched_core_fork(struct task_struct *p);
2386extern int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type,
2387				unsigned long uaddr);
2388#else
2389static inline void sched_core_free(struct task_struct *tsk) { }
2390static inline void sched_core_fork(struct task_struct *p) { }
2391#endif
2392
2393extern void sched_set_stop_task(int cpu, struct task_struct *stop);
2394
2395#endif
2396