xref: /linux-6.15/include/linux/sched.h (revision 623b4ac4)
1 #ifndef _LINUX_SCHED_H
2 #define _LINUX_SCHED_H
3 
4 /*
5  * cloning flags:
6  */
7 #define CSIGNAL		0x000000ff	/* signal mask to be sent at exit */
8 #define CLONE_VM	0x00000100	/* set if VM shared between processes */
9 #define CLONE_FS	0x00000200	/* set if fs info shared between processes */
10 #define CLONE_FILES	0x00000400	/* set if open files shared between processes */
11 #define CLONE_SIGHAND	0x00000800	/* set if signal handlers and blocked signals shared */
12 #define CLONE_PTRACE	0x00002000	/* set if we want to let tracing continue on the child too */
13 #define CLONE_VFORK	0x00004000	/* set if the parent wants the child to wake it up on mm_release */
14 #define CLONE_PARENT	0x00008000	/* set if we want to have the same parent as the cloner */
15 #define CLONE_THREAD	0x00010000	/* Same thread group? */
16 #define CLONE_NEWNS	0x00020000	/* New namespace group? */
17 #define CLONE_SYSVSEM	0x00040000	/* share system V SEM_UNDO semantics */
18 #define CLONE_SETTLS	0x00080000	/* create a new TLS for the child */
19 #define CLONE_PARENT_SETTID	0x00100000	/* set the TID in the parent */
20 #define CLONE_CHILD_CLEARTID	0x00200000	/* clear the TID in the child */
21 #define CLONE_DETACHED		0x00400000	/* Unused, ignored */
22 #define CLONE_UNTRACED		0x00800000	/* set if the tracing process can't force CLONE_PTRACE on this clone */
23 #define CLONE_CHILD_SETTID	0x01000000	/* set the TID in the child */
24 #define CLONE_STOPPED		0x02000000	/* Start in stopped state */
25 #define CLONE_NEWUTS		0x04000000	/* New utsname group? */
26 #define CLONE_NEWIPC		0x08000000	/* New ipcs */
27 #define CLONE_NEWUSER		0x10000000	/* New user namespace */
28 #define CLONE_NEWPID		0x20000000	/* New pid namespace */
29 #define CLONE_NEWNET		0x40000000	/* New network namespace */
30 #define CLONE_IO		0x80000000	/* Clone io context */
31 
32 /*
33  * Scheduling policies
34  */
35 #define SCHED_NORMAL		0
36 #define SCHED_FIFO		1
37 #define SCHED_RR		2
38 #define SCHED_BATCH		3
39 /* SCHED_ISO: reserved but not implemented yet */
40 #define SCHED_IDLE		5
41 /* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */
42 #define SCHED_RESET_ON_FORK     0x40000000
43 
44 #ifdef __KERNEL__
45 
46 struct sched_param {
47 	int sched_priority;
48 };
49 
50 #include <asm/param.h>	/* for HZ */
51 
52 #include <linux/capability.h>
53 #include <linux/threads.h>
54 #include <linux/kernel.h>
55 #include <linux/types.h>
56 #include <linux/timex.h>
57 #include <linux/jiffies.h>
58 #include <linux/rbtree.h>
59 #include <linux/thread_info.h>
60 #include <linux/cpumask.h>
61 #include <linux/errno.h>
62 #include <linux/nodemask.h>
63 #include <linux/mm_types.h>
64 
65 #include <asm/system.h>
66 #include <asm/page.h>
67 #include <asm/ptrace.h>
68 #include <asm/cputime.h>
69 
70 #include <linux/smp.h>
71 #include <linux/sem.h>
72 #include <linux/signal.h>
73 #include <linux/path.h>
74 #include <linux/compiler.h>
75 #include <linux/completion.h>
76 #include <linux/pid.h>
77 #include <linux/percpu.h>
78 #include <linux/topology.h>
79 #include <linux/proportions.h>
80 #include <linux/seccomp.h>
81 #include <linux/rcupdate.h>
82 #include <linux/rculist.h>
83 #include <linux/rtmutex.h>
84 
85 #include <linux/time.h>
86 #include <linux/param.h>
87 #include <linux/resource.h>
88 #include <linux/timer.h>
89 #include <linux/hrtimer.h>
90 #include <linux/task_io_accounting.h>
91 #include <linux/kobject.h>
92 #include <linux/latencytop.h>
93 #include <linux/cred.h>
94 
95 #include <asm/processor.h>
96 
97 struct exec_domain;
98 struct futex_pi_state;
99 struct robust_list_head;
100 struct bio;
101 struct fs_struct;
102 struct bts_context;
103 struct perf_event_context;
104 
105 /*
106  * List of flags we want to share for kernel threads,
107  * if only because they are not used by them anyway.
108  */
109 #define CLONE_KERNEL	(CLONE_FS | CLONE_FILES | CLONE_SIGHAND)
110 
111 /*
112  * These are the constant used to fake the fixed-point load-average
113  * counting. Some notes:
114  *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
115  *    a load-average precision of 10 bits integer + 11 bits fractional
116  *  - if you want to count load-averages more often, you need more
117  *    precision, or rounding will get you. With 2-second counting freq,
118  *    the EXP_n values would be 1981, 2034 and 2043 if still using only
119  *    11 bit fractions.
120  */
121 extern unsigned long avenrun[];		/* Load averages */
122 extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
123 
124 #define FSHIFT		11		/* nr of bits of precision */
125 #define FIXED_1		(1<<FSHIFT)	/* 1.0 as fixed-point */
126 #define LOAD_FREQ	(5*HZ+1)	/* 5 sec intervals */
127 #define EXP_1		1884		/* 1/exp(5sec/1min) as fixed-point */
128 #define EXP_5		2014		/* 1/exp(5sec/5min) */
129 #define EXP_15		2037		/* 1/exp(5sec/15min) */
130 
131 #define CALC_LOAD(load,exp,n) \
132 	load *= exp; \
133 	load += n*(FIXED_1-exp); \
134 	load >>= FSHIFT;
135 
136 extern unsigned long total_forks;
137 extern int nr_threads;
138 DECLARE_PER_CPU(unsigned long, process_counts);
139 extern int nr_processes(void);
140 extern unsigned long nr_running(void);
141 extern unsigned long nr_uninterruptible(void);
142 extern unsigned long nr_iowait(void);
143 extern unsigned long nr_iowait_cpu(void);
144 extern unsigned long this_cpu_load(void);
145 
146 
147 extern void calc_global_load(void);
148 
149 extern unsigned long get_parent_ip(unsigned long addr);
150 
151 struct seq_file;
152 struct cfs_rq;
153 struct task_group;
154 #ifdef CONFIG_SCHED_DEBUG
155 extern void proc_sched_show_task(struct task_struct *p, struct seq_file *m);
156 extern void proc_sched_set_task(struct task_struct *p);
157 extern void
158 print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
159 #else
160 static inline void
161 proc_sched_show_task(struct task_struct *p, struct seq_file *m)
162 {
163 }
164 static inline void proc_sched_set_task(struct task_struct *p)
165 {
166 }
167 static inline void
168 print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
169 {
170 }
171 #endif
172 
173 /*
174  * Task state bitmask. NOTE! These bits are also
175  * encoded in fs/proc/array.c: get_task_state().
176  *
177  * We have two separate sets of flags: task->state
178  * is about runnability, while task->exit_state are
179  * about the task exiting. Confusing, but this way
180  * modifying one set can't modify the other one by
181  * mistake.
182  */
183 #define TASK_RUNNING		0
184 #define TASK_INTERRUPTIBLE	1
185 #define TASK_UNINTERRUPTIBLE	2
186 #define __TASK_STOPPED		4
187 #define __TASK_TRACED		8
188 /* in tsk->exit_state */
189 #define EXIT_ZOMBIE		16
190 #define EXIT_DEAD		32
191 /* in tsk->state again */
192 #define TASK_DEAD		64
193 #define TASK_WAKEKILL		128
194 #define TASK_WAKING		256
195 #define TASK_STATE_MAX		512
196 
197 #define TASK_STATE_TO_CHAR_STR "RSDTtZXxKW"
198 
199 extern char ___assert_task_state[1 - 2*!!(
200 		sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1)];
201 
202 /* Convenience macros for the sake of set_task_state */
203 #define TASK_KILLABLE		(TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
204 #define TASK_STOPPED		(TASK_WAKEKILL | __TASK_STOPPED)
205 #define TASK_TRACED		(TASK_WAKEKILL | __TASK_TRACED)
206 
207 /* Convenience macros for the sake of wake_up */
208 #define TASK_NORMAL		(TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
209 #define TASK_ALL		(TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)
210 
211 /* get_task_state() */
212 #define TASK_REPORT		(TASK_RUNNING | TASK_INTERRUPTIBLE | \
213 				 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
214 				 __TASK_TRACED)
215 
216 #define task_is_traced(task)	((task->state & __TASK_TRACED) != 0)
217 #define task_is_stopped(task)	((task->state & __TASK_STOPPED) != 0)
218 #define task_is_stopped_or_traced(task)	\
219 			((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
220 #define task_contributes_to_load(task)	\
221 				((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
222 				 (task->flags & PF_FREEZING) == 0)
223 
224 #define __set_task_state(tsk, state_value)		\
225 	do { (tsk)->state = (state_value); } while (0)
226 #define set_task_state(tsk, state_value)		\
227 	set_mb((tsk)->state, (state_value))
228 
229 /*
230  * set_current_state() includes a barrier so that the write of current->state
231  * is correctly serialised wrt the caller's subsequent test of whether to
232  * actually sleep:
233  *
234  *	set_current_state(TASK_UNINTERRUPTIBLE);
235  *	if (do_i_need_to_sleep())
236  *		schedule();
237  *
238  * If the caller does not need such serialisation then use __set_current_state()
239  */
240 #define __set_current_state(state_value)			\
241 	do { current->state = (state_value); } while (0)
242 #define set_current_state(state_value)		\
243 	set_mb(current->state, (state_value))
244 
245 /* Task command name length */
246 #define TASK_COMM_LEN 16
247 
248 #include <linux/spinlock.h>
249 
250 /*
251  * This serializes "schedule()" and also protects
252  * the run-queue from deletions/modifications (but
253  * _adding_ to the beginning of the run-queue has
254  * a separate lock).
255  */
256 extern rwlock_t tasklist_lock;
257 extern spinlock_t mmlist_lock;
258 
259 struct task_struct;
260 
261 extern void sched_init(void);
262 extern void sched_init_smp(void);
263 extern asmlinkage void schedule_tail(struct task_struct *prev);
264 extern void init_idle(struct task_struct *idle, int cpu);
265 extern void init_idle_bootup_task(struct task_struct *idle);
266 
267 extern int runqueue_is_locked(int cpu);
268 extern void task_rq_unlock_wait(struct task_struct *p);
269 
270 extern cpumask_var_t nohz_cpu_mask;
271 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
272 extern int select_nohz_load_balancer(int cpu);
273 extern int get_nohz_load_balancer(void);
274 #else
275 static inline int select_nohz_load_balancer(int cpu)
276 {
277 	return 0;
278 }
279 #endif
280 
281 /*
282  * Only dump TASK_* tasks. (0 for all tasks)
283  */
284 extern void show_state_filter(unsigned long state_filter);
285 
286 static inline void show_state(void)
287 {
288 	show_state_filter(0);
289 }
290 
291 extern void show_regs(struct pt_regs *);
292 
293 /*
294  * TASK is a pointer to the task whose backtrace we want to see (or NULL for current
295  * task), SP is the stack pointer of the first frame that should be shown in the back
296  * trace (or NULL if the entire call-chain of the task should be shown).
297  */
298 extern void show_stack(struct task_struct *task, unsigned long *sp);
299 
300 void io_schedule(void);
301 long io_schedule_timeout(long timeout);
302 
303 extern void cpu_init (void);
304 extern void trap_init(void);
305 extern void update_process_times(int user);
306 extern void scheduler_tick(void);
307 
308 extern void sched_show_task(struct task_struct *p);
309 
310 #ifdef CONFIG_DETECT_SOFTLOCKUP
311 extern void softlockup_tick(void);
312 extern void touch_softlockup_watchdog(void);
313 extern void touch_softlockup_watchdog_sync(void);
314 extern void touch_all_softlockup_watchdogs(void);
315 extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
316 				    void __user *buffer,
317 				    size_t *lenp, loff_t *ppos);
318 extern unsigned int  softlockup_panic;
319 extern int softlockup_thresh;
320 #else
321 static inline void softlockup_tick(void)
322 {
323 }
324 static inline void touch_softlockup_watchdog(void)
325 {
326 }
327 static inline void touch_softlockup_watchdog_sync(void)
328 {
329 }
330 static inline void touch_all_softlockup_watchdogs(void)
331 {
332 }
333 #endif
334 
335 #ifdef CONFIG_DETECT_HUNG_TASK
336 extern unsigned int  sysctl_hung_task_panic;
337 extern unsigned long sysctl_hung_task_check_count;
338 extern unsigned long sysctl_hung_task_timeout_secs;
339 extern unsigned long sysctl_hung_task_warnings;
340 extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
341 					 void __user *buffer,
342 					 size_t *lenp, loff_t *ppos);
343 #endif
344 
345 /* Attach to any functions which should be ignored in wchan output. */
346 #define __sched		__attribute__((__section__(".sched.text")))
347 
348 /* Linker adds these: start and end of __sched functions */
349 extern char __sched_text_start[], __sched_text_end[];
350 
351 /* Is this address in the __sched functions? */
352 extern int in_sched_functions(unsigned long addr);
353 
354 #define	MAX_SCHEDULE_TIMEOUT	LONG_MAX
355 extern signed long schedule_timeout(signed long timeout);
356 extern signed long schedule_timeout_interruptible(signed long timeout);
357 extern signed long schedule_timeout_killable(signed long timeout);
358 extern signed long schedule_timeout_uninterruptible(signed long timeout);
359 asmlinkage void schedule(void);
360 extern int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner);
361 
362 struct nsproxy;
363 struct user_namespace;
364 
365 /*
366  * Default maximum number of active map areas, this limits the number of vmas
367  * per mm struct. Users can overwrite this number by sysctl but there is a
368  * problem.
369  *
370  * When a program's coredump is generated as ELF format, a section is created
371  * per a vma. In ELF, the number of sections is represented in unsigned short.
372  * This means the number of sections should be smaller than 65535 at coredump.
373  * Because the kernel adds some informative sections to a image of program at
374  * generating coredump, we need some margin. The number of extra sections is
375  * 1-3 now and depends on arch. We use "5" as safe margin, here.
376  */
377 #define MAPCOUNT_ELF_CORE_MARGIN	(5)
378 #define DEFAULT_MAX_MAP_COUNT	(USHORT_MAX - MAPCOUNT_ELF_CORE_MARGIN)
379 
380 extern int sysctl_max_map_count;
381 
382 #include <linux/aio.h>
383 
384 #ifdef CONFIG_MMU
385 extern void arch_pick_mmap_layout(struct mm_struct *mm);
386 extern unsigned long
387 arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
388 		       unsigned long, unsigned long);
389 extern unsigned long
390 arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
391 			  unsigned long len, unsigned long pgoff,
392 			  unsigned long flags);
393 extern void arch_unmap_area(struct mm_struct *, unsigned long);
394 extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long);
395 #else
396 static inline void arch_pick_mmap_layout(struct mm_struct *mm) {}
397 #endif
398 
399 #if USE_SPLIT_PTLOCKS
400 /*
401  * The mm counters are not protected by its page_table_lock,
402  * so must be incremented atomically.
403  */
404 #define set_mm_counter(mm, member, value) atomic_long_set(&(mm)->_##member, value)
405 #define get_mm_counter(mm, member) ((unsigned long)atomic_long_read(&(mm)->_##member))
406 #define add_mm_counter(mm, member, value) atomic_long_add(value, &(mm)->_##member)
407 #define inc_mm_counter(mm, member) atomic_long_inc(&(mm)->_##member)
408 #define dec_mm_counter(mm, member) atomic_long_dec(&(mm)->_##member)
409 
410 #else  /* !USE_SPLIT_PTLOCKS */
411 /*
412  * The mm counters are protected by its page_table_lock,
413  * so can be incremented directly.
414  */
415 #define set_mm_counter(mm, member, value) (mm)->_##member = (value)
416 #define get_mm_counter(mm, member) ((mm)->_##member)
417 #define add_mm_counter(mm, member, value) (mm)->_##member += (value)
418 #define inc_mm_counter(mm, member) (mm)->_##member++
419 #define dec_mm_counter(mm, member) (mm)->_##member--
420 
421 #endif /* !USE_SPLIT_PTLOCKS */
422 
423 #define get_mm_rss(mm)					\
424 	(get_mm_counter(mm, file_rss) + get_mm_counter(mm, anon_rss))
425 #define update_hiwater_rss(mm)	do {			\
426 	unsigned long _rss = get_mm_rss(mm);		\
427 	if ((mm)->hiwater_rss < _rss)			\
428 		(mm)->hiwater_rss = _rss;		\
429 } while (0)
430 #define update_hiwater_vm(mm)	do {			\
431 	if ((mm)->hiwater_vm < (mm)->total_vm)		\
432 		(mm)->hiwater_vm = (mm)->total_vm;	\
433 } while (0)
434 
435 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
436 {
437 	return max(mm->hiwater_rss, get_mm_rss(mm));
438 }
439 
440 static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
441 					 struct mm_struct *mm)
442 {
443 	unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
444 
445 	if (*maxrss < hiwater_rss)
446 		*maxrss = hiwater_rss;
447 }
448 
449 static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
450 {
451 	return max(mm->hiwater_vm, mm->total_vm);
452 }
453 
454 extern void set_dumpable(struct mm_struct *mm, int value);
455 extern int get_dumpable(struct mm_struct *mm);
456 
457 /* mm flags */
458 /* dumpable bits */
459 #define MMF_DUMPABLE      0  /* core dump is permitted */
460 #define MMF_DUMP_SECURELY 1  /* core file is readable only by root */
461 
462 #define MMF_DUMPABLE_BITS 2
463 #define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)
464 
465 /* coredump filter bits */
466 #define MMF_DUMP_ANON_PRIVATE	2
467 #define MMF_DUMP_ANON_SHARED	3
468 #define MMF_DUMP_MAPPED_PRIVATE	4
469 #define MMF_DUMP_MAPPED_SHARED	5
470 #define MMF_DUMP_ELF_HEADERS	6
471 #define MMF_DUMP_HUGETLB_PRIVATE 7
472 #define MMF_DUMP_HUGETLB_SHARED  8
473 
474 #define MMF_DUMP_FILTER_SHIFT	MMF_DUMPABLE_BITS
475 #define MMF_DUMP_FILTER_BITS	7
476 #define MMF_DUMP_FILTER_MASK \
477 	(((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
478 #define MMF_DUMP_FILTER_DEFAULT \
479 	((1 << MMF_DUMP_ANON_PRIVATE) |	(1 << MMF_DUMP_ANON_SHARED) |\
480 	 (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
481 
482 #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
483 # define MMF_DUMP_MASK_DEFAULT_ELF	(1 << MMF_DUMP_ELF_HEADERS)
484 #else
485 # define MMF_DUMP_MASK_DEFAULT_ELF	0
486 #endif
487 					/* leave room for more dump flags */
488 #define MMF_VM_MERGEABLE	16	/* KSM may merge identical pages */
489 
490 #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)
491 
492 struct sighand_struct {
493 	atomic_t		count;
494 	struct k_sigaction	action[_NSIG];
495 	spinlock_t		siglock;
496 	wait_queue_head_t	signalfd_wqh;
497 };
498 
499 struct pacct_struct {
500 	int			ac_flag;
501 	long			ac_exitcode;
502 	unsigned long		ac_mem;
503 	cputime_t		ac_utime, ac_stime;
504 	unsigned long		ac_minflt, ac_majflt;
505 };
506 
507 struct cpu_itimer {
508 	cputime_t expires;
509 	cputime_t incr;
510 	u32 error;
511 	u32 incr_error;
512 };
513 
514 /**
515  * struct task_cputime - collected CPU time counts
516  * @utime:		time spent in user mode, in &cputime_t units
517  * @stime:		time spent in kernel mode, in &cputime_t units
518  * @sum_exec_runtime:	total time spent on the CPU, in nanoseconds
519  *
520  * This structure groups together three kinds of CPU time that are
521  * tracked for threads and thread groups.  Most things considering
522  * CPU time want to group these counts together and treat all three
523  * of them in parallel.
524  */
525 struct task_cputime {
526 	cputime_t utime;
527 	cputime_t stime;
528 	unsigned long long sum_exec_runtime;
529 };
530 /* Alternate field names when used to cache expirations. */
531 #define prof_exp	stime
532 #define virt_exp	utime
533 #define sched_exp	sum_exec_runtime
534 
535 #define INIT_CPUTIME	\
536 	(struct task_cputime) {					\
537 		.utime = cputime_zero,				\
538 		.stime = cputime_zero,				\
539 		.sum_exec_runtime = 0,				\
540 	}
541 
542 /*
543  * Disable preemption until the scheduler is running.
544  * Reset by start_kernel()->sched_init()->init_idle().
545  *
546  * We include PREEMPT_ACTIVE to avoid cond_resched() from working
547  * before the scheduler is active -- see should_resched().
548  */
549 #define INIT_PREEMPT_COUNT	(1 + PREEMPT_ACTIVE)
550 
551 /**
552  * struct thread_group_cputimer - thread group interval timer counts
553  * @cputime:		thread group interval timers.
554  * @running:		non-zero when there are timers running and
555  * 			@cputime receives updates.
556  * @lock:		lock for fields in this struct.
557  *
558  * This structure contains the version of task_cputime, above, that is
559  * used for thread group CPU timer calculations.
560  */
561 struct thread_group_cputimer {
562 	struct task_cputime cputime;
563 	int running;
564 	spinlock_t lock;
565 };
566 
567 /*
568  * NOTE! "signal_struct" does not have it's own
569  * locking, because a shared signal_struct always
570  * implies a shared sighand_struct, so locking
571  * sighand_struct is always a proper superset of
572  * the locking of signal_struct.
573  */
574 struct signal_struct {
575 	atomic_t		count;
576 	atomic_t		live;
577 
578 	wait_queue_head_t	wait_chldexit;	/* for wait4() */
579 
580 	/* current thread group signal load-balancing target: */
581 	struct task_struct	*curr_target;
582 
583 	/* shared signal handling: */
584 	struct sigpending	shared_pending;
585 
586 	/* thread group exit support */
587 	int			group_exit_code;
588 	/* overloaded:
589 	 * - notify group_exit_task when ->count is equal to notify_count
590 	 * - everyone except group_exit_task is stopped during signal delivery
591 	 *   of fatal signals, group_exit_task processes the signal.
592 	 */
593 	int			notify_count;
594 	struct task_struct	*group_exit_task;
595 
596 	/* thread group stop support, overloads group_exit_code too */
597 	int			group_stop_count;
598 	unsigned int		flags; /* see SIGNAL_* flags below */
599 
600 	/* POSIX.1b Interval Timers */
601 	struct list_head posix_timers;
602 
603 	/* ITIMER_REAL timer for the process */
604 	struct hrtimer real_timer;
605 	struct pid *leader_pid;
606 	ktime_t it_real_incr;
607 
608 	/*
609 	 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
610 	 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
611 	 * values are defined to 0 and 1 respectively
612 	 */
613 	struct cpu_itimer it[2];
614 
615 	/*
616 	 * Thread group totals for process CPU timers.
617 	 * See thread_group_cputimer(), et al, for details.
618 	 */
619 	struct thread_group_cputimer cputimer;
620 
621 	/* Earliest-expiration cache. */
622 	struct task_cputime cputime_expires;
623 
624 	struct list_head cpu_timers[3];
625 
626 	struct pid *tty_old_pgrp;
627 
628 	/* boolean value for session group leader */
629 	int leader;
630 
631 	struct tty_struct *tty; /* NULL if no tty */
632 
633 	/*
634 	 * Cumulative resource counters for dead threads in the group,
635 	 * and for reaped dead child processes forked by this group.
636 	 * Live threads maintain their own counters and add to these
637 	 * in __exit_signal, except for the group leader.
638 	 */
639 	cputime_t utime, stime, cutime, cstime;
640 	cputime_t gtime;
641 	cputime_t cgtime;
642 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
643 	cputime_t prev_utime, prev_stime;
644 #endif
645 	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
646 	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
647 	unsigned long inblock, oublock, cinblock, coublock;
648 	unsigned long maxrss, cmaxrss;
649 	struct task_io_accounting ioac;
650 
651 	/*
652 	 * Cumulative ns of schedule CPU time fo dead threads in the
653 	 * group, not including a zombie group leader, (This only differs
654 	 * from jiffies_to_ns(utime + stime) if sched_clock uses something
655 	 * other than jiffies.)
656 	 */
657 	unsigned long long sum_sched_runtime;
658 
659 	/*
660 	 * We don't bother to synchronize most readers of this at all,
661 	 * because there is no reader checking a limit that actually needs
662 	 * to get both rlim_cur and rlim_max atomically, and either one
663 	 * alone is a single word that can safely be read normally.
664 	 * getrlimit/setrlimit use task_lock(current->group_leader) to
665 	 * protect this instead of the siglock, because they really
666 	 * have no need to disable irqs.
667 	 */
668 	struct rlimit rlim[RLIM_NLIMITS];
669 
670 #ifdef CONFIG_BSD_PROCESS_ACCT
671 	struct pacct_struct pacct;	/* per-process accounting information */
672 #endif
673 #ifdef CONFIG_TASKSTATS
674 	struct taskstats *stats;
675 #endif
676 #ifdef CONFIG_AUDIT
677 	unsigned audit_tty;
678 	struct tty_audit_buf *tty_audit_buf;
679 #endif
680 
681 	int oom_adj;	/* OOM kill score adjustment (bit shift) */
682 };
683 
684 /* Context switch must be unlocked if interrupts are to be enabled */
685 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
686 # define __ARCH_WANT_UNLOCKED_CTXSW
687 #endif
688 
689 /*
690  * Bits in flags field of signal_struct.
691  */
692 #define SIGNAL_STOP_STOPPED	0x00000001 /* job control stop in effect */
693 #define SIGNAL_STOP_DEQUEUED	0x00000002 /* stop signal dequeued */
694 #define SIGNAL_STOP_CONTINUED	0x00000004 /* SIGCONT since WCONTINUED reap */
695 #define SIGNAL_GROUP_EXIT	0x00000008 /* group exit in progress */
696 /*
697  * Pending notifications to parent.
698  */
699 #define SIGNAL_CLD_STOPPED	0x00000010
700 #define SIGNAL_CLD_CONTINUED	0x00000020
701 #define SIGNAL_CLD_MASK		(SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
702 
703 #define SIGNAL_UNKILLABLE	0x00000040 /* for init: ignore fatal signals */
704 
705 /* If true, all threads except ->group_exit_task have pending SIGKILL */
706 static inline int signal_group_exit(const struct signal_struct *sig)
707 {
708 	return	(sig->flags & SIGNAL_GROUP_EXIT) ||
709 		(sig->group_exit_task != NULL);
710 }
711 
712 /*
713  * Some day this will be a full-fledged user tracking system..
714  */
715 struct user_struct {
716 	atomic_t __count;	/* reference count */
717 	atomic_t processes;	/* How many processes does this user have? */
718 	atomic_t files;		/* How many open files does this user have? */
719 	atomic_t sigpending;	/* How many pending signals does this user have? */
720 #ifdef CONFIG_INOTIFY_USER
721 	atomic_t inotify_watches; /* How many inotify watches does this user have? */
722 	atomic_t inotify_devs;	/* How many inotify devs does this user have opened? */
723 #endif
724 #ifdef CONFIG_EPOLL
725 	atomic_t epoll_watches;	/* The number of file descriptors currently watched */
726 #endif
727 #ifdef CONFIG_POSIX_MQUEUE
728 	/* protected by mq_lock	*/
729 	unsigned long mq_bytes;	/* How many bytes can be allocated to mqueue? */
730 #endif
731 	unsigned long locked_shm; /* How many pages of mlocked shm ? */
732 
733 #ifdef CONFIG_KEYS
734 	struct key *uid_keyring;	/* UID specific keyring */
735 	struct key *session_keyring;	/* UID's default session keyring */
736 #endif
737 
738 	/* Hash table maintenance information */
739 	struct hlist_node uidhash_node;
740 	uid_t uid;
741 	struct user_namespace *user_ns;
742 
743 #ifdef CONFIG_USER_SCHED
744 	struct task_group *tg;
745 #ifdef CONFIG_SYSFS
746 	struct kobject kobj;
747 	struct delayed_work work;
748 #endif
749 #endif
750 
751 #ifdef CONFIG_PERF_EVENTS
752 	atomic_long_t locked_vm;
753 #endif
754 };
755 
756 extern int uids_sysfs_init(void);
757 
758 extern struct user_struct *find_user(uid_t);
759 
760 extern struct user_struct root_user;
761 #define INIT_USER (&root_user)
762 
763 
764 struct backing_dev_info;
765 struct reclaim_state;
766 
767 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
768 struct sched_info {
769 	/* cumulative counters */
770 	unsigned long pcount;	      /* # of times run on this cpu */
771 	unsigned long long run_delay; /* time spent waiting on a runqueue */
772 
773 	/* timestamps */
774 	unsigned long long last_arrival,/* when we last ran on a cpu */
775 			   last_queued;	/* when we were last queued to run */
776 #ifdef CONFIG_SCHEDSTATS
777 	/* BKL stats */
778 	unsigned int bkl_count;
779 #endif
780 };
781 #endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */
782 
783 #ifdef CONFIG_TASK_DELAY_ACCT
784 struct task_delay_info {
785 	spinlock_t	lock;
786 	unsigned int	flags;	/* Private per-task flags */
787 
788 	/* For each stat XXX, add following, aligned appropriately
789 	 *
790 	 * struct timespec XXX_start, XXX_end;
791 	 * u64 XXX_delay;
792 	 * u32 XXX_count;
793 	 *
794 	 * Atomicity of updates to XXX_delay, XXX_count protected by
795 	 * single lock above (split into XXX_lock if contention is an issue).
796 	 */
797 
798 	/*
799 	 * XXX_count is incremented on every XXX operation, the delay
800 	 * associated with the operation is added to XXX_delay.
801 	 * XXX_delay contains the accumulated delay time in nanoseconds.
802 	 */
803 	struct timespec blkio_start, blkio_end;	/* Shared by blkio, swapin */
804 	u64 blkio_delay;	/* wait for sync block io completion */
805 	u64 swapin_delay;	/* wait for swapin block io completion */
806 	u32 blkio_count;	/* total count of the number of sync block */
807 				/* io operations performed */
808 	u32 swapin_count;	/* total count of the number of swapin block */
809 				/* io operations performed */
810 
811 	struct timespec freepages_start, freepages_end;
812 	u64 freepages_delay;	/* wait for memory reclaim */
813 	u32 freepages_count;	/* total count of memory reclaim */
814 };
815 #endif	/* CONFIG_TASK_DELAY_ACCT */
816 
817 static inline int sched_info_on(void)
818 {
819 #ifdef CONFIG_SCHEDSTATS
820 	return 1;
821 #elif defined(CONFIG_TASK_DELAY_ACCT)
822 	extern int delayacct_on;
823 	return delayacct_on;
824 #else
825 	return 0;
826 #endif
827 }
828 
829 enum cpu_idle_type {
830 	CPU_IDLE,
831 	CPU_NOT_IDLE,
832 	CPU_NEWLY_IDLE,
833 	CPU_MAX_IDLE_TYPES
834 };
835 
836 /*
837  * sched-domains (multiprocessor balancing) declarations:
838  */
839 
840 /*
841  * Increase resolution of nice-level calculations:
842  */
843 #define SCHED_LOAD_SHIFT	10
844 #define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)
845 
846 #define SCHED_LOAD_SCALE_FUZZ	SCHED_LOAD_SCALE
847 
848 #ifdef CONFIG_SMP
849 #define SD_LOAD_BALANCE		0x0001	/* Do load balancing on this domain. */
850 #define SD_BALANCE_NEWIDLE	0x0002	/* Balance when about to become idle */
851 #define SD_BALANCE_EXEC		0x0004	/* Balance on exec */
852 #define SD_BALANCE_FORK		0x0008	/* Balance on fork, clone */
853 #define SD_BALANCE_WAKE		0x0010  /* Balance on wakeup */
854 #define SD_WAKE_AFFINE		0x0020	/* Wake task to waking CPU */
855 #define SD_PREFER_LOCAL		0x0040  /* Prefer to keep tasks local to this domain */
856 #define SD_SHARE_CPUPOWER	0x0080	/* Domain members share cpu power */
857 #define SD_POWERSAVINGS_BALANCE	0x0100	/* Balance for power savings */
858 #define SD_SHARE_PKG_RESOURCES	0x0200	/* Domain members share cpu pkg resources */
859 #define SD_SERIALIZE		0x0400	/* Only a single load balancing instance */
860 
861 #define SD_PREFER_SIBLING	0x1000	/* Prefer to place tasks in a sibling domain */
862 
863 enum powersavings_balance_level {
864 	POWERSAVINGS_BALANCE_NONE = 0,  /* No power saving load balance */
865 	POWERSAVINGS_BALANCE_BASIC,	/* Fill one thread/core/package
866 					 * first for long running threads
867 					 */
868 	POWERSAVINGS_BALANCE_WAKEUP,	/* Also bias task wakeups to semi-idle
869 					 * cpu package for power savings
870 					 */
871 	MAX_POWERSAVINGS_BALANCE_LEVELS
872 };
873 
874 extern int sched_mc_power_savings, sched_smt_power_savings;
875 
876 static inline int sd_balance_for_mc_power(void)
877 {
878 	if (sched_smt_power_savings)
879 		return SD_POWERSAVINGS_BALANCE;
880 
881 	return SD_PREFER_SIBLING;
882 }
883 
884 static inline int sd_balance_for_package_power(void)
885 {
886 	if (sched_mc_power_savings | sched_smt_power_savings)
887 		return SD_POWERSAVINGS_BALANCE;
888 
889 	return SD_PREFER_SIBLING;
890 }
891 
892 /*
893  * Optimise SD flags for power savings:
894  * SD_BALANCE_NEWIDLE helps agressive task consolidation and power savings.
895  * Keep default SD flags if sched_{smt,mc}_power_saving=0
896  */
897 
898 static inline int sd_power_saving_flags(void)
899 {
900 	if (sched_mc_power_savings | sched_smt_power_savings)
901 		return SD_BALANCE_NEWIDLE;
902 
903 	return 0;
904 }
905 
906 struct sched_group {
907 	struct sched_group *next;	/* Must be a circular list */
908 
909 	/*
910 	 * CPU power of this group, SCHED_LOAD_SCALE being max power for a
911 	 * single CPU.
912 	 */
913 	unsigned int cpu_power;
914 
915 	/*
916 	 * The CPUs this group covers.
917 	 *
918 	 * NOTE: this field is variable length. (Allocated dynamically
919 	 * by attaching extra space to the end of the structure,
920 	 * depending on how many CPUs the kernel has booted up with)
921 	 *
922 	 * It is also be embedded into static data structures at build
923 	 * time. (See 'struct static_sched_group' in kernel/sched.c)
924 	 */
925 	unsigned long cpumask[0];
926 };
927 
928 static inline struct cpumask *sched_group_cpus(struct sched_group *sg)
929 {
930 	return to_cpumask(sg->cpumask);
931 }
932 
933 enum sched_domain_level {
934 	SD_LV_NONE = 0,
935 	SD_LV_SIBLING,
936 	SD_LV_MC,
937 	SD_LV_CPU,
938 	SD_LV_NODE,
939 	SD_LV_ALLNODES,
940 	SD_LV_MAX
941 };
942 
943 struct sched_domain_attr {
944 	int relax_domain_level;
945 };
946 
947 #define SD_ATTR_INIT	(struct sched_domain_attr) {	\
948 	.relax_domain_level = -1,			\
949 }
950 
951 struct sched_domain {
952 	/* These fields must be setup */
953 	struct sched_domain *parent;	/* top domain must be null terminated */
954 	struct sched_domain *child;	/* bottom domain must be null terminated */
955 	struct sched_group *groups;	/* the balancing groups of the domain */
956 	unsigned long min_interval;	/* Minimum balance interval ms */
957 	unsigned long max_interval;	/* Maximum balance interval ms */
958 	unsigned int busy_factor;	/* less balancing by factor if busy */
959 	unsigned int imbalance_pct;	/* No balance until over watermark */
960 	unsigned int cache_nice_tries;	/* Leave cache hot tasks for # tries */
961 	unsigned int busy_idx;
962 	unsigned int idle_idx;
963 	unsigned int newidle_idx;
964 	unsigned int wake_idx;
965 	unsigned int forkexec_idx;
966 	unsigned int smt_gain;
967 	int flags;			/* See SD_* */
968 	enum sched_domain_level level;
969 
970 	/* Runtime fields. */
971 	unsigned long last_balance;	/* init to jiffies. units in jiffies */
972 	unsigned int balance_interval;	/* initialise to 1. units in ms. */
973 	unsigned int nr_balance_failed; /* initialise to 0 */
974 
975 	u64 last_update;
976 
977 #ifdef CONFIG_SCHEDSTATS
978 	/* load_balance() stats */
979 	unsigned int lb_count[CPU_MAX_IDLE_TYPES];
980 	unsigned int lb_failed[CPU_MAX_IDLE_TYPES];
981 	unsigned int lb_balanced[CPU_MAX_IDLE_TYPES];
982 	unsigned int lb_imbalance[CPU_MAX_IDLE_TYPES];
983 	unsigned int lb_gained[CPU_MAX_IDLE_TYPES];
984 	unsigned int lb_hot_gained[CPU_MAX_IDLE_TYPES];
985 	unsigned int lb_nobusyg[CPU_MAX_IDLE_TYPES];
986 	unsigned int lb_nobusyq[CPU_MAX_IDLE_TYPES];
987 
988 	/* Active load balancing */
989 	unsigned int alb_count;
990 	unsigned int alb_failed;
991 	unsigned int alb_pushed;
992 
993 	/* SD_BALANCE_EXEC stats */
994 	unsigned int sbe_count;
995 	unsigned int sbe_balanced;
996 	unsigned int sbe_pushed;
997 
998 	/* SD_BALANCE_FORK stats */
999 	unsigned int sbf_count;
1000 	unsigned int sbf_balanced;
1001 	unsigned int sbf_pushed;
1002 
1003 	/* try_to_wake_up() stats */
1004 	unsigned int ttwu_wake_remote;
1005 	unsigned int ttwu_move_affine;
1006 	unsigned int ttwu_move_balance;
1007 #endif
1008 #ifdef CONFIG_SCHED_DEBUG
1009 	char *name;
1010 #endif
1011 
1012 	/*
1013 	 * Span of all CPUs in this domain.
1014 	 *
1015 	 * NOTE: this field is variable length. (Allocated dynamically
1016 	 * by attaching extra space to the end of the structure,
1017 	 * depending on how many CPUs the kernel has booted up with)
1018 	 *
1019 	 * It is also be embedded into static data structures at build
1020 	 * time. (See 'struct static_sched_domain' in kernel/sched.c)
1021 	 */
1022 	unsigned long span[0];
1023 };
1024 
1025 static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
1026 {
1027 	return to_cpumask(sd->span);
1028 }
1029 
1030 extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
1031 				    struct sched_domain_attr *dattr_new);
1032 
1033 /* Allocate an array of sched domains, for partition_sched_domains(). */
1034 cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
1035 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
1036 
1037 /* Test a flag in parent sched domain */
1038 static inline int test_sd_parent(struct sched_domain *sd, int flag)
1039 {
1040 	if (sd->parent && (sd->parent->flags & flag))
1041 		return 1;
1042 
1043 	return 0;
1044 }
1045 
1046 unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu);
1047 unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu);
1048 
1049 #else /* CONFIG_SMP */
1050 
1051 struct sched_domain_attr;
1052 
1053 static inline void
1054 partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
1055 			struct sched_domain_attr *dattr_new)
1056 {
1057 }
1058 #endif	/* !CONFIG_SMP */
1059 
1060 
1061 struct io_context;			/* See blkdev.h */
1062 
1063 
1064 #ifdef ARCH_HAS_PREFETCH_SWITCH_STACK
1065 extern void prefetch_stack(struct task_struct *t);
1066 #else
1067 static inline void prefetch_stack(struct task_struct *t) { }
1068 #endif
1069 
1070 struct audit_context;		/* See audit.c */
1071 struct mempolicy;
1072 struct pipe_inode_info;
1073 struct uts_namespace;
1074 
1075 struct rq;
1076 struct sched_domain;
1077 
1078 /*
1079  * wake flags
1080  */
1081 #define WF_SYNC		0x01		/* waker goes to sleep after wakup */
1082 #define WF_FORK		0x02		/* child wakeup after fork */
1083 
1084 struct sched_class {
1085 	const struct sched_class *next;
1086 
1087 	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup);
1088 	void (*dequeue_task) (struct rq *rq, struct task_struct *p, int sleep);
1089 	void (*yield_task) (struct rq *rq);
1090 
1091 	void (*check_preempt_curr) (struct rq *rq, struct task_struct *p, int flags);
1092 
1093 	struct task_struct * (*pick_next_task) (struct rq *rq);
1094 	void (*put_prev_task) (struct rq *rq, struct task_struct *p);
1095 
1096 #ifdef CONFIG_SMP
1097 	int  (*select_task_rq)(struct task_struct *p, int sd_flag, int flags);
1098 
1099 	unsigned long (*load_balance) (struct rq *this_rq, int this_cpu,
1100 			struct rq *busiest, unsigned long max_load_move,
1101 			struct sched_domain *sd, enum cpu_idle_type idle,
1102 			int *all_pinned, int *this_best_prio);
1103 
1104 	int (*move_one_task) (struct rq *this_rq, int this_cpu,
1105 			      struct rq *busiest, struct sched_domain *sd,
1106 			      enum cpu_idle_type idle);
1107 	void (*pre_schedule) (struct rq *this_rq, struct task_struct *task);
1108 	void (*post_schedule) (struct rq *this_rq);
1109 	void (*task_waking) (struct rq *this_rq, struct task_struct *task);
1110 	void (*task_woken) (struct rq *this_rq, struct task_struct *task);
1111 
1112 	void (*set_cpus_allowed)(struct task_struct *p,
1113 				 const struct cpumask *newmask);
1114 
1115 	void (*rq_online)(struct rq *rq);
1116 	void (*rq_offline)(struct rq *rq);
1117 #endif
1118 
1119 	void (*set_curr_task) (struct rq *rq);
1120 	void (*task_tick) (struct rq *rq, struct task_struct *p, int queued);
1121 	void (*task_fork) (struct task_struct *p);
1122 
1123 	void (*switched_from) (struct rq *this_rq, struct task_struct *task,
1124 			       int running);
1125 	void (*switched_to) (struct rq *this_rq, struct task_struct *task,
1126 			     int running);
1127 	void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
1128 			     int oldprio, int running);
1129 
1130 	unsigned int (*get_rr_interval) (struct rq *rq,
1131 					 struct task_struct *task);
1132 
1133 #ifdef CONFIG_FAIR_GROUP_SCHED
1134 	void (*moved_group) (struct task_struct *p, int on_rq);
1135 #endif
1136 };
1137 
1138 struct load_weight {
1139 	unsigned long weight, inv_weight;
1140 };
1141 
1142 /*
1143  * CFS stats for a schedulable entity (task, task-group etc)
1144  *
1145  * Current field usage histogram:
1146  *
1147  *     4 se->block_start
1148  *     4 se->run_node
1149  *     4 se->sleep_start
1150  *     6 se->load.weight
1151  */
1152 struct sched_entity {
1153 	struct load_weight	load;		/* for load-balancing */
1154 	struct rb_node		run_node;
1155 	struct list_head	group_node;
1156 	unsigned int		on_rq;
1157 
1158 	u64			exec_start;
1159 	u64			sum_exec_runtime;
1160 	u64			vruntime;
1161 	u64			prev_sum_exec_runtime;
1162 
1163 	u64			last_wakeup;
1164 	u64			avg_overlap;
1165 
1166 	u64			nr_migrations;
1167 
1168 	u64			start_runtime;
1169 	u64			avg_wakeup;
1170 
1171 #ifdef CONFIG_SCHEDSTATS
1172 	u64			wait_start;
1173 	u64			wait_max;
1174 	u64			wait_count;
1175 	u64			wait_sum;
1176 	u64			iowait_count;
1177 	u64			iowait_sum;
1178 
1179 	u64			sleep_start;
1180 	u64			sleep_max;
1181 	s64			sum_sleep_runtime;
1182 
1183 	u64			block_start;
1184 	u64			block_max;
1185 	u64			exec_max;
1186 	u64			slice_max;
1187 
1188 	u64			nr_migrations_cold;
1189 	u64			nr_failed_migrations_affine;
1190 	u64			nr_failed_migrations_running;
1191 	u64			nr_failed_migrations_hot;
1192 	u64			nr_forced_migrations;
1193 
1194 	u64			nr_wakeups;
1195 	u64			nr_wakeups_sync;
1196 	u64			nr_wakeups_migrate;
1197 	u64			nr_wakeups_local;
1198 	u64			nr_wakeups_remote;
1199 	u64			nr_wakeups_affine;
1200 	u64			nr_wakeups_affine_attempts;
1201 	u64			nr_wakeups_passive;
1202 	u64			nr_wakeups_idle;
1203 #endif
1204 
1205 #ifdef CONFIG_FAIR_GROUP_SCHED
1206 	struct sched_entity	*parent;
1207 	/* rq on which this entity is (to be) queued: */
1208 	struct cfs_rq		*cfs_rq;
1209 	/* rq "owned" by this entity/group: */
1210 	struct cfs_rq		*my_q;
1211 #endif
1212 };
1213 
1214 struct sched_rt_entity {
1215 	struct list_head run_list;
1216 	unsigned long timeout;
1217 	unsigned int time_slice;
1218 	int nr_cpus_allowed;
1219 
1220 	struct sched_rt_entity *back;
1221 #ifdef CONFIG_RT_GROUP_SCHED
1222 	struct sched_rt_entity	*parent;
1223 	/* rq on which this entity is (to be) queued: */
1224 	struct rt_rq		*rt_rq;
1225 	/* rq "owned" by this entity/group: */
1226 	struct rt_rq		*my_q;
1227 #endif
1228 };
1229 
1230 struct rcu_node;
1231 
1232 struct task_struct {
1233 	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
1234 	void *stack;
1235 	atomic_t usage;
1236 	unsigned int flags;	/* per process flags, defined below */
1237 	unsigned int ptrace;
1238 
1239 	int lock_depth;		/* BKL lock depth */
1240 
1241 #ifdef CONFIG_SMP
1242 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
1243 	int oncpu;
1244 #endif
1245 #endif
1246 
1247 	int prio, static_prio, normal_prio;
1248 	unsigned int rt_priority;
1249 	const struct sched_class *sched_class;
1250 	struct sched_entity se;
1251 	struct sched_rt_entity rt;
1252 
1253 #ifdef CONFIG_PREEMPT_NOTIFIERS
1254 	/* list of struct preempt_notifier: */
1255 	struct hlist_head preempt_notifiers;
1256 #endif
1257 
1258 	/*
1259 	 * fpu_counter contains the number of consecutive context switches
1260 	 * that the FPU is used. If this is over a threshold, the lazy fpu
1261 	 * saving becomes unlazy to save the trap. This is an unsigned char
1262 	 * so that after 256 times the counter wraps and the behavior turns
1263 	 * lazy again; this to deal with bursty apps that only use FPU for
1264 	 * a short time
1265 	 */
1266 	unsigned char fpu_counter;
1267 #ifdef CONFIG_BLK_DEV_IO_TRACE
1268 	unsigned int btrace_seq;
1269 #endif
1270 
1271 	unsigned int policy;
1272 	cpumask_t cpus_allowed;
1273 
1274 #ifdef CONFIG_TREE_PREEMPT_RCU
1275 	int rcu_read_lock_nesting;
1276 	char rcu_read_unlock_special;
1277 	struct rcu_node *rcu_blocked_node;
1278 	struct list_head rcu_node_entry;
1279 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
1280 
1281 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1282 	struct sched_info sched_info;
1283 #endif
1284 
1285 	struct list_head tasks;
1286 	struct plist_node pushable_tasks;
1287 
1288 	struct mm_struct *mm, *active_mm;
1289 
1290 /* task state */
1291 	int exit_state;
1292 	int exit_code, exit_signal;
1293 	int pdeath_signal;  /*  The signal sent when the parent dies  */
1294 	/* ??? */
1295 	unsigned int personality;
1296 	unsigned did_exec:1;
1297 	unsigned in_execve:1;	/* Tell the LSMs that the process is doing an
1298 				 * execve */
1299 	unsigned in_iowait:1;
1300 
1301 
1302 	/* Revert to default priority/policy when forking */
1303 	unsigned sched_reset_on_fork:1;
1304 
1305 	pid_t pid;
1306 	pid_t tgid;
1307 
1308 #ifdef CONFIG_CC_STACKPROTECTOR
1309 	/* Canary value for the -fstack-protector gcc feature */
1310 	unsigned long stack_canary;
1311 #endif
1312 
1313 	/*
1314 	 * pointers to (original) parent process, youngest child, younger sibling,
1315 	 * older sibling, respectively.  (p->father can be replaced with
1316 	 * p->real_parent->pid)
1317 	 */
1318 	struct task_struct *real_parent; /* real parent process */
1319 	struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */
1320 	/*
1321 	 * children/sibling forms the list of my natural children
1322 	 */
1323 	struct list_head children;	/* list of my children */
1324 	struct list_head sibling;	/* linkage in my parent's children list */
1325 	struct task_struct *group_leader;	/* threadgroup leader */
1326 
1327 	/*
1328 	 * ptraced is the list of tasks this task is using ptrace on.
1329 	 * This includes both natural children and PTRACE_ATTACH targets.
1330 	 * p->ptrace_entry is p's link on the p->parent->ptraced list.
1331 	 */
1332 	struct list_head ptraced;
1333 	struct list_head ptrace_entry;
1334 
1335 	/*
1336 	 * This is the tracer handle for the ptrace BTS extension.
1337 	 * This field actually belongs to the ptracer task.
1338 	 */
1339 	struct bts_context *bts;
1340 
1341 	/* PID/PID hash table linkage. */
1342 	struct pid_link pids[PIDTYPE_MAX];
1343 	struct list_head thread_group;
1344 
1345 	struct completion *vfork_done;		/* for vfork() */
1346 	int __user *set_child_tid;		/* CLONE_CHILD_SETTID */
1347 	int __user *clear_child_tid;		/* CLONE_CHILD_CLEARTID */
1348 
1349 	cputime_t utime, stime, utimescaled, stimescaled;
1350 	cputime_t gtime;
1351 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
1352 	cputime_t prev_utime, prev_stime;
1353 #endif
1354 	unsigned long nvcsw, nivcsw; /* context switch counts */
1355 	struct timespec start_time; 		/* monotonic time */
1356 	struct timespec real_start_time;	/* boot based time */
1357 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
1358 	unsigned long min_flt, maj_flt;
1359 
1360 	struct task_cputime cputime_expires;
1361 	struct list_head cpu_timers[3];
1362 
1363 /* process credentials */
1364 	const struct cred *real_cred;	/* objective and real subjective task
1365 					 * credentials (COW) */
1366 	const struct cred *cred;	/* effective (overridable) subjective task
1367 					 * credentials (COW) */
1368 	struct mutex cred_guard_mutex;	/* guard against foreign influences on
1369 					 * credential calculations
1370 					 * (notably. ptrace) */
1371 	struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */
1372 
1373 	char comm[TASK_COMM_LEN]; /* executable name excluding path
1374 				     - access with [gs]et_task_comm (which lock
1375 				       it with task_lock())
1376 				     - initialized normally by setup_new_exec */
1377 /* file system info */
1378 	int link_count, total_link_count;
1379 #ifdef CONFIG_SYSVIPC
1380 /* ipc stuff */
1381 	struct sysv_sem sysvsem;
1382 #endif
1383 #ifdef CONFIG_DETECT_HUNG_TASK
1384 /* hung task detection */
1385 	unsigned long last_switch_count;
1386 #endif
1387 /* CPU-specific state of this task */
1388 	struct thread_struct thread;
1389 /* filesystem information */
1390 	struct fs_struct *fs;
1391 /* open file information */
1392 	struct files_struct *files;
1393 /* namespaces */
1394 	struct nsproxy *nsproxy;
1395 /* signal handlers */
1396 	struct signal_struct *signal;
1397 	struct sighand_struct *sighand;
1398 
1399 	sigset_t blocked, real_blocked;
1400 	sigset_t saved_sigmask;	/* restored if set_restore_sigmask() was used */
1401 	struct sigpending pending;
1402 
1403 	unsigned long sas_ss_sp;
1404 	size_t sas_ss_size;
1405 	int (*notifier)(void *priv);
1406 	void *notifier_data;
1407 	sigset_t *notifier_mask;
1408 	struct audit_context *audit_context;
1409 #ifdef CONFIG_AUDITSYSCALL
1410 	uid_t loginuid;
1411 	unsigned int sessionid;
1412 #endif
1413 	seccomp_t seccomp;
1414 
1415 /* Thread group tracking */
1416    	u32 parent_exec_id;
1417    	u32 self_exec_id;
1418 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed,
1419  * mempolicy */
1420 	spinlock_t alloc_lock;
1421 
1422 #ifdef CONFIG_GENERIC_HARDIRQS
1423 	/* IRQ handler threads */
1424 	struct irqaction *irqaction;
1425 #endif
1426 
1427 	/* Protection of the PI data structures: */
1428 	raw_spinlock_t pi_lock;
1429 
1430 #ifdef CONFIG_RT_MUTEXES
1431 	/* PI waiters blocked on a rt_mutex held by this task */
1432 	struct plist_head pi_waiters;
1433 	/* Deadlock detection and priority inheritance handling */
1434 	struct rt_mutex_waiter *pi_blocked_on;
1435 #endif
1436 
1437 #ifdef CONFIG_DEBUG_MUTEXES
1438 	/* mutex deadlock detection */
1439 	struct mutex_waiter *blocked_on;
1440 #endif
1441 #ifdef CONFIG_TRACE_IRQFLAGS
1442 	unsigned int irq_events;
1443 	unsigned long hardirq_enable_ip;
1444 	unsigned long hardirq_disable_ip;
1445 	unsigned int hardirq_enable_event;
1446 	unsigned int hardirq_disable_event;
1447 	int hardirqs_enabled;
1448 	int hardirq_context;
1449 	unsigned long softirq_disable_ip;
1450 	unsigned long softirq_enable_ip;
1451 	unsigned int softirq_disable_event;
1452 	unsigned int softirq_enable_event;
1453 	int softirqs_enabled;
1454 	int softirq_context;
1455 #endif
1456 #ifdef CONFIG_LOCKDEP
1457 # define MAX_LOCK_DEPTH 48UL
1458 	u64 curr_chain_key;
1459 	int lockdep_depth;
1460 	unsigned int lockdep_recursion;
1461 	struct held_lock held_locks[MAX_LOCK_DEPTH];
1462 	gfp_t lockdep_reclaim_gfp;
1463 #endif
1464 
1465 /* journalling filesystem info */
1466 	void *journal_info;
1467 
1468 /* stacked block device info */
1469 	struct bio *bio_list, **bio_tail;
1470 
1471 /* VM state */
1472 	struct reclaim_state *reclaim_state;
1473 
1474 	struct backing_dev_info *backing_dev_info;
1475 
1476 	struct io_context *io_context;
1477 
1478 	unsigned long ptrace_message;
1479 	siginfo_t *last_siginfo; /* For ptrace use.  */
1480 	struct task_io_accounting ioac;
1481 #if defined(CONFIG_TASK_XACCT)
1482 	u64 acct_rss_mem1;	/* accumulated rss usage */
1483 	u64 acct_vm_mem1;	/* accumulated virtual memory usage */
1484 	cputime_t acct_timexpd;	/* stime + utime since last update */
1485 #endif
1486 #ifdef CONFIG_CPUSETS
1487 	nodemask_t mems_allowed;	/* Protected by alloc_lock */
1488 	int cpuset_mem_spread_rotor;
1489 #endif
1490 #ifdef CONFIG_CGROUPS
1491 	/* Control Group info protected by css_set_lock */
1492 	struct css_set *cgroups;
1493 	/* cg_list protected by css_set_lock and tsk->alloc_lock */
1494 	struct list_head cg_list;
1495 #endif
1496 #ifdef CONFIG_FUTEX
1497 	struct robust_list_head __user *robust_list;
1498 #ifdef CONFIG_COMPAT
1499 	struct compat_robust_list_head __user *compat_robust_list;
1500 #endif
1501 	struct list_head pi_state_list;
1502 	struct futex_pi_state *pi_state_cache;
1503 #endif
1504 #ifdef CONFIG_PERF_EVENTS
1505 	struct perf_event_context *perf_event_ctxp;
1506 	struct mutex perf_event_mutex;
1507 	struct list_head perf_event_list;
1508 #endif
1509 #ifdef CONFIG_NUMA
1510 	struct mempolicy *mempolicy;	/* Protected by alloc_lock */
1511 	short il_next;
1512 #endif
1513 	atomic_t fs_excl;	/* holding fs exclusive resources */
1514 	struct rcu_head rcu;
1515 
1516 	/*
1517 	 * cache last used pipe for splice
1518 	 */
1519 	struct pipe_inode_info *splice_pipe;
1520 #ifdef	CONFIG_TASK_DELAY_ACCT
1521 	struct task_delay_info *delays;
1522 #endif
1523 #ifdef CONFIG_FAULT_INJECTION
1524 	int make_it_fail;
1525 #endif
1526 	struct prop_local_single dirties;
1527 #ifdef CONFIG_LATENCYTOP
1528 	int latency_record_count;
1529 	struct latency_record latency_record[LT_SAVECOUNT];
1530 #endif
1531 	/*
1532 	 * time slack values; these are used to round up poll() and
1533 	 * select() etc timeout values. These are in nanoseconds.
1534 	 */
1535 	unsigned long timer_slack_ns;
1536 	unsigned long default_timer_slack_ns;
1537 
1538 	struct list_head	*scm_work_list;
1539 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1540 	/* Index of current stored adress in ret_stack */
1541 	int curr_ret_stack;
1542 	/* Stack of return addresses for return function tracing */
1543 	struct ftrace_ret_stack	*ret_stack;
1544 	/* time stamp for last schedule */
1545 	unsigned long long ftrace_timestamp;
1546 	/*
1547 	 * Number of functions that haven't been traced
1548 	 * because of depth overrun.
1549 	 */
1550 	atomic_t trace_overrun;
1551 	/* Pause for the tracing */
1552 	atomic_t tracing_graph_pause;
1553 #endif
1554 #ifdef CONFIG_TRACING
1555 	/* state flags for use by tracers */
1556 	unsigned long trace;
1557 	/* bitmask of trace recursion */
1558 	unsigned long trace_recursion;
1559 #endif /* CONFIG_TRACING */
1560 	unsigned long stack_start;
1561 #ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */
1562 	struct memcg_batch_info {
1563 		int do_batch;	/* incremented when batch uncharge started */
1564 		struct mem_cgroup *memcg; /* target memcg of uncharge */
1565 		unsigned long bytes; 		/* uncharged usage */
1566 		unsigned long memsw_bytes; /* uncharged mem+swap usage */
1567 	} memcg_batch;
1568 #endif
1569 };
1570 
1571 /* Future-safe accessor for struct task_struct's cpus_allowed. */
1572 #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
1573 
1574 /*
1575  * Priority of a process goes from 0..MAX_PRIO-1, valid RT
1576  * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
1577  * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
1578  * values are inverted: lower p->prio value means higher priority.
1579  *
1580  * The MAX_USER_RT_PRIO value allows the actual maximum
1581  * RT priority to be separate from the value exported to
1582  * user-space.  This allows kernel threads to set their
1583  * priority to a value higher than any user task. Note:
1584  * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
1585  */
1586 
1587 #define MAX_USER_RT_PRIO	100
1588 #define MAX_RT_PRIO		MAX_USER_RT_PRIO
1589 
1590 #define MAX_PRIO		(MAX_RT_PRIO + 40)
1591 #define DEFAULT_PRIO		(MAX_RT_PRIO + 20)
1592 
1593 static inline int rt_prio(int prio)
1594 {
1595 	if (unlikely(prio < MAX_RT_PRIO))
1596 		return 1;
1597 	return 0;
1598 }
1599 
1600 static inline int rt_task(struct task_struct *p)
1601 {
1602 	return rt_prio(p->prio);
1603 }
1604 
1605 static inline struct pid *task_pid(struct task_struct *task)
1606 {
1607 	return task->pids[PIDTYPE_PID].pid;
1608 }
1609 
1610 static inline struct pid *task_tgid(struct task_struct *task)
1611 {
1612 	return task->group_leader->pids[PIDTYPE_PID].pid;
1613 }
1614 
1615 /*
1616  * Without tasklist or rcu lock it is not safe to dereference
1617  * the result of task_pgrp/task_session even if task == current,
1618  * we can race with another thread doing sys_setsid/sys_setpgid.
1619  */
1620 static inline struct pid *task_pgrp(struct task_struct *task)
1621 {
1622 	return task->group_leader->pids[PIDTYPE_PGID].pid;
1623 }
1624 
1625 static inline struct pid *task_session(struct task_struct *task)
1626 {
1627 	return task->group_leader->pids[PIDTYPE_SID].pid;
1628 }
1629 
1630 struct pid_namespace;
1631 
1632 /*
1633  * the helpers to get the task's different pids as they are seen
1634  * from various namespaces
1635  *
1636  * task_xid_nr()     : global id, i.e. the id seen from the init namespace;
1637  * task_xid_vnr()    : virtual id, i.e. the id seen from the pid namespace of
1638  *                     current.
1639  * task_xid_nr_ns()  : id seen from the ns specified;
1640  *
1641  * set_task_vxid()   : assigns a virtual id to a task;
1642  *
1643  * see also pid_nr() etc in include/linux/pid.h
1644  */
1645 pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
1646 			struct pid_namespace *ns);
1647 
1648 static inline pid_t task_pid_nr(struct task_struct *tsk)
1649 {
1650 	return tsk->pid;
1651 }
1652 
1653 static inline pid_t task_pid_nr_ns(struct task_struct *tsk,
1654 					struct pid_namespace *ns)
1655 {
1656 	return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1657 }
1658 
1659 static inline pid_t task_pid_vnr(struct task_struct *tsk)
1660 {
1661 	return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1662 }
1663 
1664 
1665 static inline pid_t task_tgid_nr(struct task_struct *tsk)
1666 {
1667 	return tsk->tgid;
1668 }
1669 
1670 pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);
1671 
1672 static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1673 {
1674 	return pid_vnr(task_tgid(tsk));
1675 }
1676 
1677 
1678 static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,
1679 					struct pid_namespace *ns)
1680 {
1681 	return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1682 }
1683 
1684 static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1685 {
1686 	return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1687 }
1688 
1689 
1690 static inline pid_t task_session_nr_ns(struct task_struct *tsk,
1691 					struct pid_namespace *ns)
1692 {
1693 	return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1694 }
1695 
1696 static inline pid_t task_session_vnr(struct task_struct *tsk)
1697 {
1698 	return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1699 }
1700 
1701 /* obsolete, do not use */
1702 static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1703 {
1704 	return task_pgrp_nr_ns(tsk, &init_pid_ns);
1705 }
1706 
1707 /**
1708  * pid_alive - check that a task structure is not stale
1709  * @p: Task structure to be checked.
1710  *
1711  * Test if a process is not yet dead (at most zombie state)
1712  * If pid_alive fails, then pointers within the task structure
1713  * can be stale and must not be dereferenced.
1714  */
1715 static inline int pid_alive(struct task_struct *p)
1716 {
1717 	return p->pids[PIDTYPE_PID].pid != NULL;
1718 }
1719 
1720 /**
1721  * is_global_init - check if a task structure is init
1722  * @tsk: Task structure to be checked.
1723  *
1724  * Check if a task structure is the first user space task the kernel created.
1725  */
1726 static inline int is_global_init(struct task_struct *tsk)
1727 {
1728 	return tsk->pid == 1;
1729 }
1730 
1731 /*
1732  * is_container_init:
1733  * check whether in the task is init in its own pid namespace.
1734  */
1735 extern int is_container_init(struct task_struct *tsk);
1736 
1737 extern struct pid *cad_pid;
1738 
1739 extern void free_task(struct task_struct *tsk);
1740 #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
1741 
1742 extern void __put_task_struct(struct task_struct *t);
1743 
1744 static inline void put_task_struct(struct task_struct *t)
1745 {
1746 	if (atomic_dec_and_test(&t->usage))
1747 		__put_task_struct(t);
1748 }
1749 
1750 extern void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
1751 extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
1752 
1753 /*
1754  * Per process flags
1755  */
1756 #define PF_ALIGNWARN	0x00000001	/* Print alignment warning msgs */
1757 					/* Not implemented yet, only for 486*/
1758 #define PF_STARTING	0x00000002	/* being created */
1759 #define PF_EXITING	0x00000004	/* getting shut down */
1760 #define PF_EXITPIDONE	0x00000008	/* pi exit done on shut down */
1761 #define PF_VCPU		0x00000010	/* I'm a virtual CPU */
1762 #define PF_FORKNOEXEC	0x00000040	/* forked but didn't exec */
1763 #define PF_MCE_PROCESS  0x00000080      /* process policy on mce errors */
1764 #define PF_SUPERPRIV	0x00000100	/* used super-user privileges */
1765 #define PF_DUMPCORE	0x00000200	/* dumped core */
1766 #define PF_SIGNALED	0x00000400	/* killed by a signal */
1767 #define PF_MEMALLOC	0x00000800	/* Allocating memory */
1768 #define PF_FLUSHER	0x00001000	/* responsible for disk writeback */
1769 #define PF_USED_MATH	0x00002000	/* if unset the fpu must be initialized before use */
1770 #define PF_FREEZING	0x00004000	/* freeze in progress. do not account to load */
1771 #define PF_NOFREEZE	0x00008000	/* this thread should not be frozen */
1772 #define PF_FROZEN	0x00010000	/* frozen for system suspend */
1773 #define PF_FSTRANS	0x00020000	/* inside a filesystem transaction */
1774 #define PF_KSWAPD	0x00040000	/* I am kswapd */
1775 #define PF_OOM_ORIGIN	0x00080000	/* Allocating much memory to others */
1776 #define PF_LESS_THROTTLE 0x00100000	/* Throttle me less: I clean memory */
1777 #define PF_KTHREAD	0x00200000	/* I am a kernel thread */
1778 #define PF_RANDOMIZE	0x00400000	/* randomize virtual address space */
1779 #define PF_SWAPWRITE	0x00800000	/* Allowed to write to swap */
1780 #define PF_SPREAD_PAGE	0x01000000	/* Spread page cache over cpuset */
1781 #define PF_SPREAD_SLAB	0x02000000	/* Spread some slab caches over cpuset */
1782 #define PF_THREAD_BOUND	0x04000000	/* Thread bound to specific cpu */
1783 #define PF_MCE_EARLY    0x08000000      /* Early kill for mce process policy */
1784 #define PF_MEMPOLICY	0x10000000	/* Non-default NUMA mempolicy */
1785 #define PF_MUTEX_TESTER	0x20000000	/* Thread belongs to the rt mutex tester */
1786 #define PF_FREEZER_SKIP	0x40000000	/* Freezer should not count it as freezeable */
1787 #define PF_FREEZER_NOSIG 0x80000000	/* Freezer won't send signals to it */
1788 
1789 /*
1790  * Only the _current_ task can read/write to tsk->flags, but other
1791  * tasks can access tsk->flags in readonly mode for example
1792  * with tsk_used_math (like during threaded core dumping).
1793  * There is however an exception to this rule during ptrace
1794  * or during fork: the ptracer task is allowed to write to the
1795  * child->flags of its traced child (same goes for fork, the parent
1796  * can write to the child->flags), because we're guaranteed the
1797  * child is not running and in turn not changing child->flags
1798  * at the same time the parent does it.
1799  */
1800 #define clear_stopped_child_used_math(child) do { (child)->flags &= ~PF_USED_MATH; } while (0)
1801 #define set_stopped_child_used_math(child) do { (child)->flags |= PF_USED_MATH; } while (0)
1802 #define clear_used_math() clear_stopped_child_used_math(current)
1803 #define set_used_math() set_stopped_child_used_math(current)
1804 #define conditional_stopped_child_used_math(condition, child) \
1805 	do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1806 #define conditional_used_math(condition) \
1807 	conditional_stopped_child_used_math(condition, current)
1808 #define copy_to_stopped_child_used_math(child) \
1809 	do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1810 /* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1811 #define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
1812 #define used_math() tsk_used_math(current)
1813 
1814 #ifdef CONFIG_TREE_PREEMPT_RCU
1815 
1816 #define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
1817 #define RCU_READ_UNLOCK_NEED_QS (1 << 1) /* RCU core needs CPU response. */
1818 
1819 static inline void rcu_copy_process(struct task_struct *p)
1820 {
1821 	p->rcu_read_lock_nesting = 0;
1822 	p->rcu_read_unlock_special = 0;
1823 	p->rcu_blocked_node = NULL;
1824 	INIT_LIST_HEAD(&p->rcu_node_entry);
1825 }
1826 
1827 #else
1828 
1829 static inline void rcu_copy_process(struct task_struct *p)
1830 {
1831 }
1832 
1833 #endif
1834 
1835 #ifdef CONFIG_SMP
1836 extern int set_cpus_allowed_ptr(struct task_struct *p,
1837 				const struct cpumask *new_mask);
1838 #else
1839 static inline int set_cpus_allowed_ptr(struct task_struct *p,
1840 				       const struct cpumask *new_mask)
1841 {
1842 	if (!cpumask_test_cpu(0, new_mask))
1843 		return -EINVAL;
1844 	return 0;
1845 }
1846 #endif
1847 
1848 #ifndef CONFIG_CPUMASK_OFFSTACK
1849 static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
1850 {
1851 	return set_cpus_allowed_ptr(p, &new_mask);
1852 }
1853 #endif
1854 
1855 /*
1856  * Architectures can set this to 1 if they have specified
1857  * CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
1858  * but then during bootup it turns out that sched_clock()
1859  * is reliable after all:
1860  */
1861 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
1862 extern int sched_clock_stable;
1863 #endif
1864 
1865 /* ftrace calls sched_clock() directly */
1866 extern unsigned long long notrace sched_clock(void);
1867 
1868 extern void sched_clock_init(void);
1869 extern u64 sched_clock_cpu(int cpu);
1870 
1871 #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
1872 static inline void sched_clock_tick(void)
1873 {
1874 }
1875 
1876 static inline void sched_clock_idle_sleep_event(void)
1877 {
1878 }
1879 
1880 static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
1881 {
1882 }
1883 #else
1884 extern void sched_clock_tick(void);
1885 extern void sched_clock_idle_sleep_event(void);
1886 extern void sched_clock_idle_wakeup_event(u64 delta_ns);
1887 #endif
1888 
1889 /*
1890  * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
1891  * clock constructed from sched_clock():
1892  */
1893 extern unsigned long long cpu_clock(int cpu);
1894 
1895 extern unsigned long long
1896 task_sched_runtime(struct task_struct *task);
1897 extern unsigned long long thread_group_sched_runtime(struct task_struct *task);
1898 
1899 /* sched_exec is called by processes performing an exec */
1900 #ifdef CONFIG_SMP
1901 extern void sched_exec(void);
1902 #else
1903 #define sched_exec()   {}
1904 #endif
1905 
1906 extern void sched_clock_idle_sleep_event(void);
1907 extern void sched_clock_idle_wakeup_event(u64 delta_ns);
1908 
1909 #ifdef CONFIG_HOTPLUG_CPU
1910 extern void idle_task_exit(void);
1911 #else
1912 static inline void idle_task_exit(void) {}
1913 #endif
1914 
1915 extern void sched_idle_next(void);
1916 
1917 #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
1918 extern void wake_up_idle_cpu(int cpu);
1919 #else
1920 static inline void wake_up_idle_cpu(int cpu) { }
1921 #endif
1922 
1923 extern unsigned int sysctl_sched_latency;
1924 extern unsigned int sysctl_sched_min_granularity;
1925 extern unsigned int sysctl_sched_wakeup_granularity;
1926 extern unsigned int sysctl_sched_shares_ratelimit;
1927 extern unsigned int sysctl_sched_shares_thresh;
1928 extern unsigned int sysctl_sched_child_runs_first;
1929 
1930 enum sched_tunable_scaling {
1931 	SCHED_TUNABLESCALING_NONE,
1932 	SCHED_TUNABLESCALING_LOG,
1933 	SCHED_TUNABLESCALING_LINEAR,
1934 	SCHED_TUNABLESCALING_END,
1935 };
1936 extern enum sched_tunable_scaling sysctl_sched_tunable_scaling;
1937 
1938 #ifdef CONFIG_SCHED_DEBUG
1939 extern unsigned int sysctl_sched_migration_cost;
1940 extern unsigned int sysctl_sched_nr_migrate;
1941 extern unsigned int sysctl_sched_time_avg;
1942 extern unsigned int sysctl_timer_migration;
1943 
1944 int sched_proc_update_handler(struct ctl_table *table, int write,
1945 		void __user *buffer, size_t *length,
1946 		loff_t *ppos);
1947 #endif
1948 #ifdef CONFIG_SCHED_DEBUG
1949 static inline unsigned int get_sysctl_timer_migration(void)
1950 {
1951 	return sysctl_timer_migration;
1952 }
1953 #else
1954 static inline unsigned int get_sysctl_timer_migration(void)
1955 {
1956 	return 1;
1957 }
1958 #endif
1959 extern unsigned int sysctl_sched_rt_period;
1960 extern int sysctl_sched_rt_runtime;
1961 
1962 int sched_rt_handler(struct ctl_table *table, int write,
1963 		void __user *buffer, size_t *lenp,
1964 		loff_t *ppos);
1965 
1966 extern unsigned int sysctl_sched_compat_yield;
1967 
1968 #ifdef CONFIG_RT_MUTEXES
1969 extern int rt_mutex_getprio(struct task_struct *p);
1970 extern void rt_mutex_setprio(struct task_struct *p, int prio);
1971 extern void rt_mutex_adjust_pi(struct task_struct *p);
1972 #else
1973 static inline int rt_mutex_getprio(struct task_struct *p)
1974 {
1975 	return p->normal_prio;
1976 }
1977 # define rt_mutex_adjust_pi(p)		do { } while (0)
1978 #endif
1979 
1980 extern void set_user_nice(struct task_struct *p, long nice);
1981 extern int task_prio(const struct task_struct *p);
1982 extern int task_nice(const struct task_struct *p);
1983 extern int can_nice(const struct task_struct *p, const int nice);
1984 extern int task_curr(const struct task_struct *p);
1985 extern int idle_cpu(int cpu);
1986 extern int sched_setscheduler(struct task_struct *, int, struct sched_param *);
1987 extern int sched_setscheduler_nocheck(struct task_struct *, int,
1988 				      struct sched_param *);
1989 extern struct task_struct *idle_task(int cpu);
1990 extern struct task_struct *curr_task(int cpu);
1991 extern void set_curr_task(int cpu, struct task_struct *p);
1992 
1993 void yield(void);
1994 
1995 /*
1996  * The default (Linux) execution domain.
1997  */
1998 extern struct exec_domain	default_exec_domain;
1999 
2000 union thread_union {
2001 	struct thread_info thread_info;
2002 	unsigned long stack[THREAD_SIZE/sizeof(long)];
2003 };
2004 
2005 #ifndef __HAVE_ARCH_KSTACK_END
2006 static inline int kstack_end(void *addr)
2007 {
2008 	/* Reliable end of stack detection:
2009 	 * Some APM bios versions misalign the stack
2010 	 */
2011 	return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*)));
2012 }
2013 #endif
2014 
2015 extern union thread_union init_thread_union;
2016 extern struct task_struct init_task;
2017 
2018 extern struct   mm_struct init_mm;
2019 
2020 extern struct pid_namespace init_pid_ns;
2021 
2022 /*
2023  * find a task by one of its numerical ids
2024  *
2025  * find_task_by_pid_ns():
2026  *      finds a task by its pid in the specified namespace
2027  * find_task_by_vpid():
2028  *      finds a task by its virtual pid
2029  *
2030  * see also find_vpid() etc in include/linux/pid.h
2031  */
2032 
2033 extern struct task_struct *find_task_by_vpid(pid_t nr);
2034 extern struct task_struct *find_task_by_pid_ns(pid_t nr,
2035 		struct pid_namespace *ns);
2036 
2037 extern void __set_special_pids(struct pid *pid);
2038 
2039 /* per-UID process charging. */
2040 extern struct user_struct * alloc_uid(struct user_namespace *, uid_t);
2041 static inline struct user_struct *get_uid(struct user_struct *u)
2042 {
2043 	atomic_inc(&u->__count);
2044 	return u;
2045 }
2046 extern void free_uid(struct user_struct *);
2047 extern void release_uids(struct user_namespace *ns);
2048 
2049 #include <asm/current.h>
2050 
2051 extern void do_timer(unsigned long ticks);
2052 
2053 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
2054 extern int wake_up_process(struct task_struct *tsk);
2055 extern void wake_up_new_task(struct task_struct *tsk,
2056 				unsigned long clone_flags);
2057 #ifdef CONFIG_SMP
2058  extern void kick_process(struct task_struct *tsk);
2059 #else
2060  static inline void kick_process(struct task_struct *tsk) { }
2061 #endif
2062 extern void sched_fork(struct task_struct *p, int clone_flags);
2063 extern void sched_dead(struct task_struct *p);
2064 
2065 extern void proc_caches_init(void);
2066 extern void flush_signals(struct task_struct *);
2067 extern void __flush_signals(struct task_struct *);
2068 extern void ignore_signals(struct task_struct *);
2069 extern void flush_signal_handlers(struct task_struct *, int force_default);
2070 extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
2071 
2072 static inline int dequeue_signal_lock(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
2073 {
2074 	unsigned long flags;
2075 	int ret;
2076 
2077 	spin_lock_irqsave(&tsk->sighand->siglock, flags);
2078 	ret = dequeue_signal(tsk, mask, info);
2079 	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2080 
2081 	return ret;
2082 }
2083 
2084 extern void block_all_signals(int (*notifier)(void *priv), void *priv,
2085 			      sigset_t *mask);
2086 extern void unblock_all_signals(void);
2087 extern void release_task(struct task_struct * p);
2088 extern int send_sig_info(int, struct siginfo *, struct task_struct *);
2089 extern int force_sigsegv(int, struct task_struct *);
2090 extern int force_sig_info(int, struct siginfo *, struct task_struct *);
2091 extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
2092 extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
2093 extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_t, u32);
2094 extern int kill_pgrp(struct pid *pid, int sig, int priv);
2095 extern int kill_pid(struct pid *pid, int sig, int priv);
2096 extern int kill_proc_info(int, struct siginfo *, pid_t);
2097 extern int do_notify_parent(struct task_struct *, int);
2098 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
2099 extern void force_sig(int, struct task_struct *);
2100 extern int send_sig(int, struct task_struct *, int);
2101 extern void zap_other_threads(struct task_struct *p);
2102 extern struct sigqueue *sigqueue_alloc(void);
2103 extern void sigqueue_free(struct sigqueue *);
2104 extern int send_sigqueue(struct sigqueue *,  struct task_struct *, int group);
2105 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
2106 extern int do_sigaltstack(const stack_t __user *, stack_t __user *, unsigned long);
2107 
2108 static inline int kill_cad_pid(int sig, int priv)
2109 {
2110 	return kill_pid(cad_pid, sig, priv);
2111 }
2112 
2113 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
2114 #define SEND_SIG_NOINFO ((struct siginfo *) 0)
2115 #define SEND_SIG_PRIV	((struct siginfo *) 1)
2116 #define SEND_SIG_FORCED	((struct siginfo *) 2)
2117 
2118 /*
2119  * True if we are on the alternate signal stack.
2120  */
2121 static inline int on_sig_stack(unsigned long sp)
2122 {
2123 #ifdef CONFIG_STACK_GROWSUP
2124 	return sp >= current->sas_ss_sp &&
2125 		sp - current->sas_ss_sp < current->sas_ss_size;
2126 #else
2127 	return sp > current->sas_ss_sp &&
2128 		sp - current->sas_ss_sp <= current->sas_ss_size;
2129 #endif
2130 }
2131 
2132 static inline int sas_ss_flags(unsigned long sp)
2133 {
2134 	return (current->sas_ss_size == 0 ? SS_DISABLE
2135 		: on_sig_stack(sp) ? SS_ONSTACK : 0);
2136 }
2137 
2138 /*
2139  * Routines for handling mm_structs
2140  */
2141 extern struct mm_struct * mm_alloc(void);
2142 
2143 /* mmdrop drops the mm and the page tables */
2144 extern void __mmdrop(struct mm_struct *);
2145 static inline void mmdrop(struct mm_struct * mm)
2146 {
2147 	if (unlikely(atomic_dec_and_test(&mm->mm_count)))
2148 		__mmdrop(mm);
2149 }
2150 
2151 /* mmput gets rid of the mappings and all user-space */
2152 extern void mmput(struct mm_struct *);
2153 /* Grab a reference to a task's mm, if it is not already going away */
2154 extern struct mm_struct *get_task_mm(struct task_struct *task);
2155 /* Remove the current tasks stale references to the old mm_struct */
2156 extern void mm_release(struct task_struct *, struct mm_struct *);
2157 /* Allocate a new mm structure and copy contents from tsk->mm */
2158 extern struct mm_struct *dup_mm(struct task_struct *tsk);
2159 
2160 extern int copy_thread(unsigned long, unsigned long, unsigned long,
2161 			struct task_struct *, struct pt_regs *);
2162 extern void flush_thread(void);
2163 extern void exit_thread(void);
2164 
2165 extern void exit_files(struct task_struct *);
2166 extern void __cleanup_signal(struct signal_struct *);
2167 extern void __cleanup_sighand(struct sighand_struct *);
2168 
2169 extern void exit_itimers(struct signal_struct *);
2170 extern void flush_itimer_signals(void);
2171 
2172 extern NORET_TYPE void do_group_exit(int);
2173 
2174 extern void daemonize(const char *, ...);
2175 extern int allow_signal(int);
2176 extern int disallow_signal(int);
2177 
2178 extern int do_execve(char *, char __user * __user *, char __user * __user *, struct pt_regs *);
2179 extern long do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *);
2180 struct task_struct *fork_idle(int);
2181 
2182 extern void set_task_comm(struct task_struct *tsk, char *from);
2183 extern char *get_task_comm(char *to, struct task_struct *tsk);
2184 
2185 #ifdef CONFIG_SMP
2186 extern void wait_task_context_switch(struct task_struct *p);
2187 extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
2188 #else
2189 static inline void wait_task_context_switch(struct task_struct *p) {}
2190 static inline unsigned long wait_task_inactive(struct task_struct *p,
2191 					       long match_state)
2192 {
2193 	return 1;
2194 }
2195 #endif
2196 
2197 #define next_task(p) \
2198 	list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
2199 
2200 #define for_each_process(p) \
2201 	for (p = &init_task ; (p = next_task(p)) != &init_task ; )
2202 
2203 extern bool current_is_single_threaded(void);
2204 
2205 /*
2206  * Careful: do_each_thread/while_each_thread is a double loop so
2207  *          'break' will not work as expected - use goto instead.
2208  */
2209 #define do_each_thread(g, t) \
2210 	for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
2211 
2212 #define while_each_thread(g, t) \
2213 	while ((t = next_thread(t)) != g)
2214 
2215 /* de_thread depends on thread_group_leader not being a pid based check */
2216 #define thread_group_leader(p)	(p == p->group_leader)
2217 
2218 /* Do to the insanities of de_thread it is possible for a process
2219  * to have the pid of the thread group leader without actually being
2220  * the thread group leader.  For iteration through the pids in proc
2221  * all we care about is that we have a task with the appropriate
2222  * pid, we don't actually care if we have the right task.
2223  */
2224 static inline int has_group_leader_pid(struct task_struct *p)
2225 {
2226 	return p->pid == p->tgid;
2227 }
2228 
2229 static inline
2230 int same_thread_group(struct task_struct *p1, struct task_struct *p2)
2231 {
2232 	return p1->tgid == p2->tgid;
2233 }
2234 
2235 static inline struct task_struct *next_thread(const struct task_struct *p)
2236 {
2237 	return list_entry_rcu(p->thread_group.next,
2238 			      struct task_struct, thread_group);
2239 }
2240 
2241 static inline int thread_group_empty(struct task_struct *p)
2242 {
2243 	return list_empty(&p->thread_group);
2244 }
2245 
2246 #define delay_group_leader(p) \
2247 		(thread_group_leader(p) && !thread_group_empty(p))
2248 
2249 static inline int task_detached(struct task_struct *p)
2250 {
2251 	return p->exit_signal == -1;
2252 }
2253 
2254 /*
2255  * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
2256  * subscriptions and synchronises with wait4().  Also used in procfs.  Also
2257  * pins the final release of task.io_context.  Also protects ->cpuset and
2258  * ->cgroup.subsys[].
2259  *
2260  * Nests both inside and outside of read_lock(&tasklist_lock).
2261  * It must not be nested with write_lock_irq(&tasklist_lock),
2262  * neither inside nor outside.
2263  */
2264 static inline void task_lock(struct task_struct *p)
2265 {
2266 	spin_lock(&p->alloc_lock);
2267 }
2268 
2269 static inline void task_unlock(struct task_struct *p)
2270 {
2271 	spin_unlock(&p->alloc_lock);
2272 }
2273 
2274 extern struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
2275 							unsigned long *flags);
2276 
2277 static inline void unlock_task_sighand(struct task_struct *tsk,
2278 						unsigned long *flags)
2279 {
2280 	spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
2281 }
2282 
2283 #ifndef __HAVE_THREAD_FUNCTIONS
2284 
2285 #define task_thread_info(task)	((struct thread_info *)(task)->stack)
2286 #define task_stack_page(task)	((task)->stack)
2287 
2288 static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)
2289 {
2290 	*task_thread_info(p) = *task_thread_info(org);
2291 	task_thread_info(p)->task = p;
2292 }
2293 
2294 static inline unsigned long *end_of_stack(struct task_struct *p)
2295 {
2296 	return (unsigned long *)(task_thread_info(p) + 1);
2297 }
2298 
2299 #endif
2300 
2301 static inline int object_is_on_stack(void *obj)
2302 {
2303 	void *stack = task_stack_page(current);
2304 
2305 	return (obj >= stack) && (obj < (stack + THREAD_SIZE));
2306 }
2307 
2308 extern void thread_info_cache_init(void);
2309 
2310 #ifdef CONFIG_DEBUG_STACK_USAGE
2311 static inline unsigned long stack_not_used(struct task_struct *p)
2312 {
2313 	unsigned long *n = end_of_stack(p);
2314 
2315 	do { 	/* Skip over canary */
2316 		n++;
2317 	} while (!*n);
2318 
2319 	return (unsigned long)n - (unsigned long)end_of_stack(p);
2320 }
2321 #endif
2322 
2323 /* set thread flags in other task's structures
2324  * - see asm/thread_info.h for TIF_xxxx flags available
2325  */
2326 static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
2327 {
2328 	set_ti_thread_flag(task_thread_info(tsk), flag);
2329 }
2330 
2331 static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2332 {
2333 	clear_ti_thread_flag(task_thread_info(tsk), flag);
2334 }
2335 
2336 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
2337 {
2338 	return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
2339 }
2340 
2341 static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2342 {
2343 	return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
2344 }
2345 
2346 static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
2347 {
2348 	return test_ti_thread_flag(task_thread_info(tsk), flag);
2349 }
2350 
2351 static inline void set_tsk_need_resched(struct task_struct *tsk)
2352 {
2353 	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2354 }
2355 
2356 static inline void clear_tsk_need_resched(struct task_struct *tsk)
2357 {
2358 	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2359 }
2360 
2361 static inline int test_tsk_need_resched(struct task_struct *tsk)
2362 {
2363 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
2364 }
2365 
2366 static inline int restart_syscall(void)
2367 {
2368 	set_tsk_thread_flag(current, TIF_SIGPENDING);
2369 	return -ERESTARTNOINTR;
2370 }
2371 
2372 static inline int signal_pending(struct task_struct *p)
2373 {
2374 	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
2375 }
2376 
2377 static inline int __fatal_signal_pending(struct task_struct *p)
2378 {
2379 	return unlikely(sigismember(&p->pending.signal, SIGKILL));
2380 }
2381 
2382 static inline int fatal_signal_pending(struct task_struct *p)
2383 {
2384 	return signal_pending(p) && __fatal_signal_pending(p);
2385 }
2386 
2387 static inline int signal_pending_state(long state, struct task_struct *p)
2388 {
2389 	if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
2390 		return 0;
2391 	if (!signal_pending(p))
2392 		return 0;
2393 
2394 	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
2395 }
2396 
2397 static inline int need_resched(void)
2398 {
2399 	return unlikely(test_thread_flag(TIF_NEED_RESCHED));
2400 }
2401 
2402 /*
2403  * cond_resched() and cond_resched_lock(): latency reduction via
2404  * explicit rescheduling in places that are safe. The return
2405  * value indicates whether a reschedule was done in fact.
2406  * cond_resched_lock() will drop the spinlock before scheduling,
2407  * cond_resched_softirq() will enable bhs before scheduling.
2408  */
2409 extern int _cond_resched(void);
2410 
2411 #define cond_resched() ({			\
2412 	__might_sleep(__FILE__, __LINE__, 0);	\
2413 	_cond_resched();			\
2414 })
2415 
2416 extern int __cond_resched_lock(spinlock_t *lock);
2417 
2418 #ifdef CONFIG_PREEMPT
2419 #define PREEMPT_LOCK_OFFSET	PREEMPT_OFFSET
2420 #else
2421 #define PREEMPT_LOCK_OFFSET	0
2422 #endif
2423 
2424 #define cond_resched_lock(lock) ({				\
2425 	__might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
2426 	__cond_resched_lock(lock);				\
2427 })
2428 
2429 extern int __cond_resched_softirq(void);
2430 
2431 #define cond_resched_softirq() ({				\
2432 	__might_sleep(__FILE__, __LINE__, SOFTIRQ_OFFSET);	\
2433 	__cond_resched_softirq();				\
2434 })
2435 
2436 /*
2437  * Does a critical section need to be broken due to another
2438  * task waiting?: (technically does not depend on CONFIG_PREEMPT,
2439  * but a general need for low latency)
2440  */
2441 static inline int spin_needbreak(spinlock_t *lock)
2442 {
2443 #ifdef CONFIG_PREEMPT
2444 	return spin_is_contended(lock);
2445 #else
2446 	return 0;
2447 #endif
2448 }
2449 
2450 /*
2451  * Thread group CPU time accounting.
2452  */
2453 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
2454 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);
2455 
2456 static inline void thread_group_cputime_init(struct signal_struct *sig)
2457 {
2458 	sig->cputimer.cputime = INIT_CPUTIME;
2459 	spin_lock_init(&sig->cputimer.lock);
2460 	sig->cputimer.running = 0;
2461 }
2462 
2463 static inline void thread_group_cputime_free(struct signal_struct *sig)
2464 {
2465 }
2466 
2467 /*
2468  * Reevaluate whether the task has signals pending delivery.
2469  * Wake the task if so.
2470  * This is required every time the blocked sigset_t changes.
2471  * callers must hold sighand->siglock.
2472  */
2473 extern void recalc_sigpending_and_wake(struct task_struct *t);
2474 extern void recalc_sigpending(void);
2475 
2476 extern void signal_wake_up(struct task_struct *t, int resume_stopped);
2477 
2478 /*
2479  * Wrappers for p->thread_info->cpu access. No-op on UP.
2480  */
2481 #ifdef CONFIG_SMP
2482 
2483 static inline unsigned int task_cpu(const struct task_struct *p)
2484 {
2485 	return task_thread_info(p)->cpu;
2486 }
2487 
2488 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
2489 
2490 #else
2491 
2492 static inline unsigned int task_cpu(const struct task_struct *p)
2493 {
2494 	return 0;
2495 }
2496 
2497 static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
2498 {
2499 }
2500 
2501 #endif /* CONFIG_SMP */
2502 
2503 #ifdef CONFIG_TRACING
2504 extern void
2505 __trace_special(void *__tr, void *__data,
2506 		unsigned long arg1, unsigned long arg2, unsigned long arg3);
2507 #else
2508 static inline void
2509 __trace_special(void *__tr, void *__data,
2510 		unsigned long arg1, unsigned long arg2, unsigned long arg3)
2511 {
2512 }
2513 #endif
2514 
2515 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
2516 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
2517 
2518 extern void normalize_rt_tasks(void);
2519 
2520 #ifdef CONFIG_GROUP_SCHED
2521 
2522 extern struct task_group init_task_group;
2523 #ifdef CONFIG_USER_SCHED
2524 extern struct task_group root_task_group;
2525 extern void set_tg_uid(struct user_struct *user);
2526 #endif
2527 
2528 extern struct task_group *sched_create_group(struct task_group *parent);
2529 extern void sched_destroy_group(struct task_group *tg);
2530 extern void sched_move_task(struct task_struct *tsk);
2531 #ifdef CONFIG_FAIR_GROUP_SCHED
2532 extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
2533 extern unsigned long sched_group_shares(struct task_group *tg);
2534 #endif
2535 #ifdef CONFIG_RT_GROUP_SCHED
2536 extern int sched_group_set_rt_runtime(struct task_group *tg,
2537 				      long rt_runtime_us);
2538 extern long sched_group_rt_runtime(struct task_group *tg);
2539 extern int sched_group_set_rt_period(struct task_group *tg,
2540 				      long rt_period_us);
2541 extern long sched_group_rt_period(struct task_group *tg);
2542 extern int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk);
2543 #endif
2544 #endif
2545 
2546 extern int task_can_switch_user(struct user_struct *up,
2547 					struct task_struct *tsk);
2548 
2549 #ifdef CONFIG_TASK_XACCT
2550 static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
2551 {
2552 	tsk->ioac.rchar += amt;
2553 }
2554 
2555 static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
2556 {
2557 	tsk->ioac.wchar += amt;
2558 }
2559 
2560 static inline void inc_syscr(struct task_struct *tsk)
2561 {
2562 	tsk->ioac.syscr++;
2563 }
2564 
2565 static inline void inc_syscw(struct task_struct *tsk)
2566 {
2567 	tsk->ioac.syscw++;
2568 }
2569 #else
2570 static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
2571 {
2572 }
2573 
2574 static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
2575 {
2576 }
2577 
2578 static inline void inc_syscr(struct task_struct *tsk)
2579 {
2580 }
2581 
2582 static inline void inc_syscw(struct task_struct *tsk)
2583 {
2584 }
2585 #endif
2586 
2587 #ifndef TASK_SIZE_OF
2588 #define TASK_SIZE_OF(tsk)	TASK_SIZE
2589 #endif
2590 
2591 /*
2592  * Call the function if the target task is executing on a CPU right now:
2593  */
2594 extern void task_oncpu_function_call(struct task_struct *p,
2595 				     void (*func) (void *info), void *info);
2596 
2597 
2598 #ifdef CONFIG_MM_OWNER
2599 extern void mm_update_next_owner(struct mm_struct *mm);
2600 extern void mm_init_owner(struct mm_struct *mm, struct task_struct *p);
2601 #else
2602 static inline void mm_update_next_owner(struct mm_struct *mm)
2603 {
2604 }
2605 
2606 static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
2607 {
2608 }
2609 #endif /* CONFIG_MM_OWNER */
2610 
2611 static inline unsigned long task_rlimit(const struct task_struct *tsk,
2612 		unsigned int limit)
2613 {
2614 	return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_cur);
2615 }
2616 
2617 static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
2618 		unsigned int limit)
2619 {
2620 	return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_max);
2621 }
2622 
2623 static inline unsigned long rlimit(unsigned int limit)
2624 {
2625 	return task_rlimit(current, limit);
2626 }
2627 
2628 static inline unsigned long rlimit_max(unsigned int limit)
2629 {
2630 	return task_rlimit_max(current, limit);
2631 }
2632 
2633 #endif /* __KERNEL__ */
2634 
2635 #endif
2636