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Linux/include/linux/sched.h

  1 #ifndef _LINUX_SCHED_H
  2 #define _LINUX_SCHED_H
  3 
  4 #include <uapi/linux/sched.h>
  5 
  6 #include <linux/sched/prio.h>
  7 
  8 
  9 struct sched_param {
 10         int sched_priority;
 11 };
 12 
 13 #include <asm/param.h>  /* for HZ */
 14 
 15 #include <linux/capability.h>
 16 #include <linux/threads.h>
 17 #include <linux/kernel.h>
 18 #include <linux/types.h>
 19 #include <linux/timex.h>
 20 #include <linux/jiffies.h>
 21 #include <linux/plist.h>
 22 #include <linux/rbtree.h>
 23 #include <linux/thread_info.h>
 24 #include <linux/cpumask.h>
 25 #include <linux/errno.h>
 26 #include <linux/nodemask.h>
 27 #include <linux/mm_types.h>
 28 #include <linux/preempt_mask.h>
 29 
 30 #include <asm/page.h>
 31 #include <asm/ptrace.h>
 32 #include <linux/cputime.h>
 33 
 34 #include <linux/smp.h>
 35 #include <linux/sem.h>
 36 #include <linux/signal.h>
 37 #include <linux/compiler.h>
 38 #include <linux/completion.h>
 39 #include <linux/pid.h>
 40 #include <linux/percpu.h>
 41 #include <linux/topology.h>
 42 #include <linux/proportions.h>
 43 #include <linux/seccomp.h>
 44 #include <linux/rcupdate.h>
 45 #include <linux/rculist.h>
 46 #include <linux/rtmutex.h>
 47 
 48 #include <linux/time.h>
 49 #include <linux/param.h>
 50 #include <linux/resource.h>
 51 #include <linux/timer.h>
 52 #include <linux/hrtimer.h>
 53 #include <linux/task_io_accounting.h>
 54 #include <linux/latencytop.h>
 55 #include <linux/cred.h>
 56 #include <linux/llist.h>
 57 #include <linux/uidgid.h>
 58 #include <linux/gfp.h>
 59 
 60 #include <asm/processor.h>
 61 
 62 #define SCHED_ATTR_SIZE_VER0    48      /* sizeof first published struct */
 63 
 64 /*
 65  * Extended scheduling parameters data structure.
 66  *
 67  * This is needed because the original struct sched_param can not be
 68  * altered without introducing ABI issues with legacy applications
 69  * (e.g., in sched_getparam()).
 70  *
 71  * However, the possibility of specifying more than just a priority for
 72  * the tasks may be useful for a wide variety of application fields, e.g.,
 73  * multimedia, streaming, automation and control, and many others.
 74  *
 75  * This variant (sched_attr) is meant at describing a so-called
 76  * sporadic time-constrained task. In such model a task is specified by:
 77  *  - the activation period or minimum instance inter-arrival time;
 78  *  - the maximum (or average, depending on the actual scheduling
 79  *    discipline) computation time of all instances, a.k.a. runtime;
 80  *  - the deadline (relative to the actual activation time) of each
 81  *    instance.
 82  * Very briefly, a periodic (sporadic) task asks for the execution of
 83  * some specific computation --which is typically called an instance--
 84  * (at most) every period. Moreover, each instance typically lasts no more
 85  * than the runtime and must be completed by time instant t equal to
 86  * the instance activation time + the deadline.
 87  *
 88  * This is reflected by the actual fields of the sched_attr structure:
 89  *
 90  *  @size               size of the structure, for fwd/bwd compat.
 91  *
 92  *  @sched_policy       task's scheduling policy
 93  *  @sched_flags        for customizing the scheduler behaviour
 94  *  @sched_nice         task's nice value      (SCHED_NORMAL/BATCH)
 95  *  @sched_priority     task's static priority (SCHED_FIFO/RR)
 96  *  @sched_deadline     representative of the task's deadline
 97  *  @sched_runtime      representative of the task's runtime
 98  *  @sched_period       representative of the task's period
 99  *
100  * Given this task model, there are a multiplicity of scheduling algorithms
101  * and policies, that can be used to ensure all the tasks will make their
102  * timing constraints.
103  *
104  * As of now, the SCHED_DEADLINE policy (sched_dl scheduling class) is the
105  * only user of this new interface. More information about the algorithm
106  * available in the scheduling class file or in Documentation/.
107  */
108 struct sched_attr {
109         u32 size;
110 
111         u32 sched_policy;
112         u64 sched_flags;
113 
114         /* SCHED_NORMAL, SCHED_BATCH */
115         s32 sched_nice;
116 
117         /* SCHED_FIFO, SCHED_RR */
118         u32 sched_priority;
119 
120         /* SCHED_DEADLINE */
121         u64 sched_runtime;
122         u64 sched_deadline;
123         u64 sched_period;
124 };
125 
126 struct exec_domain;
127 struct futex_pi_state;
128 struct robust_list_head;
129 struct bio_list;
130 struct fs_struct;
131 struct perf_event_context;
132 struct blk_plug;
133 struct filename;
134 
135 #define VMACACHE_BITS 2
136 #define VMACACHE_SIZE (1U << VMACACHE_BITS)
137 #define VMACACHE_MASK (VMACACHE_SIZE - 1)
138 
139 /*
140  * List of flags we want to share for kernel threads,
141  * if only because they are not used by them anyway.
142  */
143 #define CLONE_KERNEL    (CLONE_FS | CLONE_FILES | CLONE_SIGHAND)
144 
145 /*
146  * These are the constant used to fake the fixed-point load-average
147  * counting. Some notes:
148  *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
149  *    a load-average precision of 10 bits integer + 11 bits fractional
150  *  - if you want to count load-averages more often, you need more
151  *    precision, or rounding will get you. With 2-second counting freq,
152  *    the EXP_n values would be 1981, 2034 and 2043 if still using only
153  *    11 bit fractions.
154  */
155 extern unsigned long avenrun[];         /* Load averages */
156 extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
157 
158 #define FSHIFT          11              /* nr of bits of precision */
159 #define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
160 #define LOAD_FREQ       (5*HZ+1)        /* 5 sec intervals */
161 #define EXP_1           1884            /* 1/exp(5sec/1min) as fixed-point */
162 #define EXP_5           2014            /* 1/exp(5sec/5min) */
163 #define EXP_15          2037            /* 1/exp(5sec/15min) */
164 
165 #define CALC_LOAD(load,exp,n) \
166         load *= exp; \
167         load += n*(FIXED_1-exp); \
168         load >>= FSHIFT;
169 
170 extern unsigned long total_forks;
171 extern int nr_threads;
172 DECLARE_PER_CPU(unsigned long, process_counts);
173 extern int nr_processes(void);
174 extern unsigned long nr_running(void);
175 extern unsigned long nr_iowait(void);
176 extern unsigned long nr_iowait_cpu(int cpu);
177 extern unsigned long this_cpu_load(void);
178 
179 
180 extern void calc_global_load(unsigned long ticks);
181 extern void update_cpu_load_nohz(void);
182 
183 extern unsigned long get_parent_ip(unsigned long addr);
184 
185 extern void dump_cpu_task(int cpu);
186 
187 struct seq_file;
188 struct cfs_rq;
189 struct task_group;
190 #ifdef CONFIG_SCHED_DEBUG
191 extern void proc_sched_show_task(struct task_struct *p, struct seq_file *m);
192 extern void proc_sched_set_task(struct task_struct *p);
193 extern void
194 print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
195 #endif
196 
197 /*
198  * Task state bitmask. NOTE! These bits are also
199  * encoded in fs/proc/array.c: get_task_state().
200  *
201  * We have two separate sets of flags: task->state
202  * is about runnability, while task->exit_state are
203  * about the task exiting. Confusing, but this way
204  * modifying one set can't modify the other one by
205  * mistake.
206  */
207 #define TASK_RUNNING            0
208 #define TASK_INTERRUPTIBLE      1
209 #define TASK_UNINTERRUPTIBLE    2
210 #define __TASK_STOPPED          4
211 #define __TASK_TRACED           8
212 /* in tsk->exit_state */
213 #define EXIT_DEAD               16
214 #define EXIT_ZOMBIE             32
215 #define EXIT_TRACE              (EXIT_ZOMBIE | EXIT_DEAD)
216 /* in tsk->state again */
217 #define TASK_DEAD               64
218 #define TASK_WAKEKILL           128
219 #define TASK_WAKING             256
220 #define TASK_PARKED             512
221 #define TASK_STATE_MAX          1024
222 
223 #define TASK_STATE_TO_CHAR_STR "RSDTtXZxKWP"
224 
225 extern char ___assert_task_state[1 - 2*!!(
226                 sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1)];
227 
228 /* Convenience macros for the sake of set_task_state */
229 #define TASK_KILLABLE           (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
230 #define TASK_STOPPED            (TASK_WAKEKILL | __TASK_STOPPED)
231 #define TASK_TRACED             (TASK_WAKEKILL | __TASK_TRACED)
232 
233 /* Convenience macros for the sake of wake_up */
234 #define TASK_NORMAL             (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
235 #define TASK_ALL                (TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)
236 
237 /* get_task_state() */
238 #define TASK_REPORT             (TASK_RUNNING | TASK_INTERRUPTIBLE | \
239                                  TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
240                                  __TASK_TRACED | EXIT_ZOMBIE | EXIT_DEAD)
241 
242 #define task_is_traced(task)    ((task->state & __TASK_TRACED) != 0)
243 #define task_is_stopped(task)   ((task->state & __TASK_STOPPED) != 0)
244 #define task_is_stopped_or_traced(task) \
245                         ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
246 #define task_contributes_to_load(task)  \
247                                 ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
248                                  (task->flags & PF_FROZEN) == 0)
249 
250 #define __set_task_state(tsk, state_value)              \
251         do { (tsk)->state = (state_value); } while (0)
252 #define set_task_state(tsk, state_value)                \
253         set_mb((tsk)->state, (state_value))
254 
255 /*
256  * set_current_state() includes a barrier so that the write of current->state
257  * is correctly serialised wrt the caller's subsequent test of whether to
258  * actually sleep:
259  *
260  *      set_current_state(TASK_UNINTERRUPTIBLE);
261  *      if (do_i_need_to_sleep())
262  *              schedule();
263  *
264  * If the caller does not need such serialisation then use __set_current_state()
265  */
266 #define __set_current_state(state_value)                        \
267         do { current->state = (state_value); } while (0)
268 #define set_current_state(state_value)          \
269         set_mb(current->state, (state_value))
270 
271 /* Task command name length */
272 #define TASK_COMM_LEN 16
273 
274 #include <linux/spinlock.h>
275 
276 /*
277  * This serializes "schedule()" and also protects
278  * the run-queue from deletions/modifications (but
279  * _adding_ to the beginning of the run-queue has
280  * a separate lock).
281  */
282 extern rwlock_t tasklist_lock;
283 extern spinlock_t mmlist_lock;
284 
285 struct task_struct;
286 
287 #ifdef CONFIG_PROVE_RCU
288 extern int lockdep_tasklist_lock_is_held(void);
289 #endif /* #ifdef CONFIG_PROVE_RCU */
290 
291 extern void sched_init(void);
292 extern void sched_init_smp(void);
293 extern asmlinkage void schedule_tail(struct task_struct *prev);
294 extern void init_idle(struct task_struct *idle, int cpu);
295 extern void init_idle_bootup_task(struct task_struct *idle);
296 
297 extern int runqueue_is_locked(int cpu);
298 
299 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
300 extern void nohz_balance_enter_idle(int cpu);
301 extern void set_cpu_sd_state_idle(void);
302 extern int get_nohz_timer_target(int pinned);
303 #else
304 static inline void nohz_balance_enter_idle(int cpu) { }
305 static inline void set_cpu_sd_state_idle(void) { }
306 static inline int get_nohz_timer_target(int pinned)
307 {
308         return smp_processor_id();
309 }
310 #endif
311 
312 /*
313  * Only dump TASK_* tasks. (0 for all tasks)
314  */
315 extern void show_state_filter(unsigned long state_filter);
316 
317 static inline void show_state(void)
318 {
319         show_state_filter(0);
320 }
321 
322 extern void show_regs(struct pt_regs *);
323 
324 /*
325  * TASK is a pointer to the task whose backtrace we want to see (or NULL for current
326  * task), SP is the stack pointer of the first frame that should be shown in the back
327  * trace (or NULL if the entire call-chain of the task should be shown).
328  */
329 extern void show_stack(struct task_struct *task, unsigned long *sp);
330 
331 void io_schedule(void);
332 long io_schedule_timeout(long timeout);
333 
334 extern void cpu_init (void);
335 extern void trap_init(void);
336 extern void update_process_times(int user);
337 extern void scheduler_tick(void);
338 
339 extern void sched_show_task(struct task_struct *p);
340 
341 #ifdef CONFIG_LOCKUP_DETECTOR
342 extern void touch_softlockup_watchdog(void);
343 extern void touch_softlockup_watchdog_sync(void);
344 extern void touch_all_softlockup_watchdogs(void);
345 extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
346                                   void __user *buffer,
347                                   size_t *lenp, loff_t *ppos);
348 extern unsigned int  softlockup_panic;
349 void lockup_detector_init(void);
350 #else
351 static inline void touch_softlockup_watchdog(void)
352 {
353 }
354 static inline void touch_softlockup_watchdog_sync(void)
355 {
356 }
357 static inline void touch_all_softlockup_watchdogs(void)
358 {
359 }
360 static inline void lockup_detector_init(void)
361 {
362 }
363 #endif
364 
365 #ifdef CONFIG_DETECT_HUNG_TASK
366 void reset_hung_task_detector(void);
367 #else
368 static inline void reset_hung_task_detector(void)
369 {
370 }
371 #endif
372 
373 /* Attach to any functions which should be ignored in wchan output. */
374 #define __sched         __attribute__((__section__(".sched.text")))
375 
376 /* Linker adds these: start and end of __sched functions */
377 extern char __sched_text_start[], __sched_text_end[];
378 
379 /* Is this address in the __sched functions? */
380 extern int in_sched_functions(unsigned long addr);
381 
382 #define MAX_SCHEDULE_TIMEOUT    LONG_MAX
383 extern signed long schedule_timeout(signed long timeout);
384 extern signed long schedule_timeout_interruptible(signed long timeout);
385 extern signed long schedule_timeout_killable(signed long timeout);
386 extern signed long schedule_timeout_uninterruptible(signed long timeout);
387 asmlinkage void schedule(void);
388 extern void schedule_preempt_disabled(void);
389 
390 struct nsproxy;
391 struct user_namespace;
392 
393 #ifdef CONFIG_MMU
394 extern void arch_pick_mmap_layout(struct mm_struct *mm);
395 extern unsigned long
396 arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
397                        unsigned long, unsigned long);
398 extern unsigned long
399 arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
400                           unsigned long len, unsigned long pgoff,
401                           unsigned long flags);
402 #else
403 static inline void arch_pick_mmap_layout(struct mm_struct *mm) {}
404 #endif
405 
406 #define SUID_DUMP_DISABLE       0       /* No setuid dumping */
407 #define SUID_DUMP_USER          1       /* Dump as user of process */
408 #define SUID_DUMP_ROOT          2       /* Dump as root */
409 
410 /* mm flags */
411 
412 /* for SUID_DUMP_* above */
413 #define MMF_DUMPABLE_BITS 2
414 #define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)
415 
416 extern void set_dumpable(struct mm_struct *mm, int value);
417 /*
418  * This returns the actual value of the suid_dumpable flag. For things
419  * that are using this for checking for privilege transitions, it must
420  * test against SUID_DUMP_USER rather than treating it as a boolean
421  * value.
422  */
423 static inline int __get_dumpable(unsigned long mm_flags)
424 {
425         return mm_flags & MMF_DUMPABLE_MASK;
426 }
427 
428 static inline int get_dumpable(struct mm_struct *mm)
429 {
430         return __get_dumpable(mm->flags);
431 }
432 
433 /* coredump filter bits */
434 #define MMF_DUMP_ANON_PRIVATE   2
435 #define MMF_DUMP_ANON_SHARED    3
436 #define MMF_DUMP_MAPPED_PRIVATE 4
437 #define MMF_DUMP_MAPPED_SHARED  5
438 #define MMF_DUMP_ELF_HEADERS    6
439 #define MMF_DUMP_HUGETLB_PRIVATE 7
440 #define MMF_DUMP_HUGETLB_SHARED  8
441 
442 #define MMF_DUMP_FILTER_SHIFT   MMF_DUMPABLE_BITS
443 #define MMF_DUMP_FILTER_BITS    7
444 #define MMF_DUMP_FILTER_MASK \
445         (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
446 #define MMF_DUMP_FILTER_DEFAULT \
447         ((1 << MMF_DUMP_ANON_PRIVATE) | (1 << MMF_DUMP_ANON_SHARED) |\
448          (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
449 
450 #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
451 # define MMF_DUMP_MASK_DEFAULT_ELF      (1 << MMF_DUMP_ELF_HEADERS)
452 #else
453 # define MMF_DUMP_MASK_DEFAULT_ELF      0
454 #endif
455                                         /* leave room for more dump flags */
456 #define MMF_VM_MERGEABLE        16      /* KSM may merge identical pages */
457 #define MMF_VM_HUGEPAGE         17      /* set when VM_HUGEPAGE is set on vma */
458 #define MMF_EXE_FILE_CHANGED    18      /* see prctl_set_mm_exe_file() */
459 
460 #define MMF_HAS_UPROBES         19      /* has uprobes */
461 #define MMF_RECALC_UPROBES      20      /* MMF_HAS_UPROBES can be wrong */
462 
463 #define MMF_INIT_MASK           (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)
464 
465 struct sighand_struct {
466         atomic_t                count;
467         struct k_sigaction      action[_NSIG];
468         spinlock_t              siglock;
469         wait_queue_head_t       signalfd_wqh;
470 };
471 
472 struct pacct_struct {
473         int                     ac_flag;
474         long                    ac_exitcode;
475         unsigned long           ac_mem;
476         cputime_t               ac_utime, ac_stime;
477         unsigned long           ac_minflt, ac_majflt;
478 };
479 
480 struct cpu_itimer {
481         cputime_t expires;
482         cputime_t incr;
483         u32 error;
484         u32 incr_error;
485 };
486 
487 /**
488  * struct cputime - snaphsot of system and user cputime
489  * @utime: time spent in user mode
490  * @stime: time spent in system mode
491  *
492  * Gathers a generic snapshot of user and system time.
493  */
494 struct cputime {
495         cputime_t utime;
496         cputime_t stime;
497 };
498 
499 /**
500  * struct task_cputime - collected CPU time counts
501  * @utime:              time spent in user mode, in &cputime_t units
502  * @stime:              time spent in kernel mode, in &cputime_t units
503  * @sum_exec_runtime:   total time spent on the CPU, in nanoseconds
504  *
505  * This is an extension of struct cputime that includes the total runtime
506  * spent by the task from the scheduler point of view.
507  *
508  * As a result, this structure groups together three kinds of CPU time
509  * that are tracked for threads and thread groups.  Most things considering
510  * CPU time want to group these counts together and treat all three
511  * of them in parallel.
512  */
513 struct task_cputime {
514         cputime_t utime;
515         cputime_t stime;
516         unsigned long long sum_exec_runtime;
517 };
518 /* Alternate field names when used to cache expirations. */
519 #define prof_exp        stime
520 #define virt_exp        utime
521 #define sched_exp       sum_exec_runtime
522 
523 #define INIT_CPUTIME    \
524         (struct task_cputime) {                                 \
525                 .utime = 0,                                     \
526                 .stime = 0,                                     \
527                 .sum_exec_runtime = 0,                          \
528         }
529 
530 #ifdef CONFIG_PREEMPT_COUNT
531 #define PREEMPT_DISABLED        (1 + PREEMPT_ENABLED)
532 #else
533 #define PREEMPT_DISABLED        PREEMPT_ENABLED
534 #endif
535 
536 /*
537  * Disable preemption until the scheduler is running.
538  * Reset by start_kernel()->sched_init()->init_idle().
539  *
540  * We include PREEMPT_ACTIVE to avoid cond_resched() from working
541  * before the scheduler is active -- see should_resched().
542  */
543 #define INIT_PREEMPT_COUNT      (PREEMPT_DISABLED + PREEMPT_ACTIVE)
544 
545 /**
546  * struct thread_group_cputimer - thread group interval timer counts
547  * @cputime:            thread group interval timers.
548  * @running:            non-zero when there are timers running and
549  *                      @cputime receives updates.
550  * @lock:               lock for fields in this struct.
551  *
552  * This structure contains the version of task_cputime, above, that is
553  * used for thread group CPU timer calculations.
554  */
555 struct thread_group_cputimer {
556         struct task_cputime cputime;
557         int running;
558         raw_spinlock_t lock;
559 };
560 
561 #include <linux/rwsem.h>
562 struct autogroup;
563 
564 /*
565  * NOTE! "signal_struct" does not have its own
566  * locking, because a shared signal_struct always
567  * implies a shared sighand_struct, so locking
568  * sighand_struct is always a proper superset of
569  * the locking of signal_struct.
570  */
571 struct signal_struct {
572         atomic_t                sigcnt;
573         atomic_t                live;
574         int                     nr_threads;
575         struct list_head        thread_head;
576 
577         wait_queue_head_t       wait_chldexit;  /* for wait4() */
578 
579         /* current thread group signal load-balancing target: */
580         struct task_struct      *curr_target;
581 
582         /* shared signal handling: */
583         struct sigpending       shared_pending;
584 
585         /* thread group exit support */
586         int                     group_exit_code;
587         /* overloaded:
588          * - notify group_exit_task when ->count is equal to notify_count
589          * - everyone except group_exit_task is stopped during signal delivery
590          *   of fatal signals, group_exit_task processes the signal.
591          */
592         int                     notify_count;
593         struct task_struct      *group_exit_task;
594 
595         /* thread group stop support, overloads group_exit_code too */
596         int                     group_stop_count;
597         unsigned int            flags; /* see SIGNAL_* flags below */
598 
599         /*
600          * PR_SET_CHILD_SUBREAPER marks a process, like a service
601          * manager, to re-parent orphan (double-forking) child processes
602          * to this process instead of 'init'. The service manager is
603          * able to receive SIGCHLD signals and is able to investigate
604          * the process until it calls wait(). All children of this
605          * process will inherit a flag if they should look for a
606          * child_subreaper process at exit.
607          */
608         unsigned int            is_child_subreaper:1;
609         unsigned int            has_child_subreaper:1;
610 
611         /* POSIX.1b Interval Timers */
612         int                     posix_timer_id;
613         struct list_head        posix_timers;
614 
615         /* ITIMER_REAL timer for the process */
616         struct hrtimer real_timer;
617         struct pid *leader_pid;
618         ktime_t it_real_incr;
619 
620         /*
621          * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
622          * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
623          * values are defined to 0 and 1 respectively
624          */
625         struct cpu_itimer it[2];
626 
627         /*
628          * Thread group totals for process CPU timers.
629          * See thread_group_cputimer(), et al, for details.
630          */
631         struct thread_group_cputimer cputimer;
632 
633         /* Earliest-expiration cache. */
634         struct task_cputime cputime_expires;
635 
636         struct list_head cpu_timers[3];
637 
638         struct pid *tty_old_pgrp;
639 
640         /* boolean value for session group leader */
641         int leader;
642 
643         struct tty_struct *tty; /* NULL if no tty */
644 
645 #ifdef CONFIG_SCHED_AUTOGROUP
646         struct autogroup *autogroup;
647 #endif
648         /*
649          * Cumulative resource counters for dead threads in the group,
650          * and for reaped dead child processes forked by this group.
651          * Live threads maintain their own counters and add to these
652          * in __exit_signal, except for the group leader.
653          */
654         cputime_t utime, stime, cutime, cstime;
655         cputime_t gtime;
656         cputime_t cgtime;
657 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
658         struct cputime prev_cputime;
659 #endif
660         unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
661         unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
662         unsigned long inblock, oublock, cinblock, coublock;
663         unsigned long maxrss, cmaxrss;
664         struct task_io_accounting ioac;
665 
666         /*
667          * Cumulative ns of schedule CPU time fo dead threads in the
668          * group, not including a zombie group leader, (This only differs
669          * from jiffies_to_ns(utime + stime) if sched_clock uses something
670          * other than jiffies.)
671          */
672         unsigned long long sum_sched_runtime;
673 
674         /*
675          * We don't bother to synchronize most readers of this at all,
676          * because there is no reader checking a limit that actually needs
677          * to get both rlim_cur and rlim_max atomically, and either one
678          * alone is a single word that can safely be read normally.
679          * getrlimit/setrlimit use task_lock(current->group_leader) to
680          * protect this instead of the siglock, because they really
681          * have no need to disable irqs.
682          */
683         struct rlimit rlim[RLIM_NLIMITS];
684 
685 #ifdef CONFIG_BSD_PROCESS_ACCT
686         struct pacct_struct pacct;      /* per-process accounting information */
687 #endif
688 #ifdef CONFIG_TASKSTATS
689         struct taskstats *stats;
690 #endif
691 #ifdef CONFIG_AUDIT
692         unsigned audit_tty;
693         unsigned audit_tty_log_passwd;
694         struct tty_audit_buf *tty_audit_buf;
695 #endif
696 #ifdef CONFIG_CGROUPS
697         /*
698          * group_rwsem prevents new tasks from entering the threadgroup and
699          * member tasks from exiting,a more specifically, setting of
700          * PF_EXITING.  fork and exit paths are protected with this rwsem
701          * using threadgroup_change_begin/end().  Users which require
702          * threadgroup to remain stable should use threadgroup_[un]lock()
703          * which also takes care of exec path.  Currently, cgroup is the
704          * only user.
705          */
706         struct rw_semaphore group_rwsem;
707 #endif
708 
709         oom_flags_t oom_flags;
710         short oom_score_adj;            /* OOM kill score adjustment */
711         short oom_score_adj_min;        /* OOM kill score adjustment min value.
712                                          * Only settable by CAP_SYS_RESOURCE. */
713 
714         struct mutex cred_guard_mutex;  /* guard against foreign influences on
715                                          * credential calculations
716                                          * (notably. ptrace) */
717 };
718 
719 /*
720  * Bits in flags field of signal_struct.
721  */
722 #define SIGNAL_STOP_STOPPED     0x00000001 /* job control stop in effect */
723 #define SIGNAL_STOP_CONTINUED   0x00000002 /* SIGCONT since WCONTINUED reap */
724 #define SIGNAL_GROUP_EXIT       0x00000004 /* group exit in progress */
725 #define SIGNAL_GROUP_COREDUMP   0x00000008 /* coredump in progress */
726 /*
727  * Pending notifications to parent.
728  */
729 #define SIGNAL_CLD_STOPPED      0x00000010
730 #define SIGNAL_CLD_CONTINUED    0x00000020
731 #define SIGNAL_CLD_MASK         (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
732 
733 #define SIGNAL_UNKILLABLE       0x00000040 /* for init: ignore fatal signals */
734 
735 /* If true, all threads except ->group_exit_task have pending SIGKILL */
736 static inline int signal_group_exit(const struct signal_struct *sig)
737 {
738         return  (sig->flags & SIGNAL_GROUP_EXIT) ||
739                 (sig->group_exit_task != NULL);
740 }
741 
742 /*
743  * Some day this will be a full-fledged user tracking system..
744  */
745 struct user_struct {
746         atomic_t __count;       /* reference count */
747         atomic_t processes;     /* How many processes does this user have? */
748         atomic_t files;         /* How many open files does this user have? */
749         atomic_t sigpending;    /* How many pending signals does this user have? */
750 #ifdef CONFIG_INOTIFY_USER
751         atomic_t inotify_watches; /* How many inotify watches does this user have? */
752         atomic_t inotify_devs;  /* How many inotify devs does this user have opened? */
753 #endif
754 #ifdef CONFIG_FANOTIFY
755         atomic_t fanotify_listeners;
756 #endif
757 #ifdef CONFIG_EPOLL
758         atomic_long_t epoll_watches; /* The number of file descriptors currently watched */
759 #endif
760 #ifdef CONFIG_POSIX_MQUEUE
761         /* protected by mq_lock */
762         unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */
763 #endif
764         unsigned long locked_shm; /* How many pages of mlocked shm ? */
765 
766 #ifdef CONFIG_KEYS
767         struct key *uid_keyring;        /* UID specific keyring */
768         struct key *session_keyring;    /* UID's default session keyring */
769 #endif
770 
771         /* Hash table maintenance information */
772         struct hlist_node uidhash_node;
773         kuid_t uid;
774 
775 #ifdef CONFIG_PERF_EVENTS
776         atomic_long_t locked_vm;
777 #endif
778 };
779 
780 extern int uids_sysfs_init(void);
781 
782 extern struct user_struct *find_user(kuid_t);
783 
784 extern struct user_struct root_user;
785 #define INIT_USER (&root_user)
786 
787 
788 struct backing_dev_info;
789 struct reclaim_state;
790 
791 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
792 struct sched_info {
793         /* cumulative counters */
794         unsigned long pcount;         /* # of times run on this cpu */
795         unsigned long long run_delay; /* time spent waiting on a runqueue */
796 
797         /* timestamps */
798         unsigned long long last_arrival,/* when we last ran on a cpu */
799                            last_queued; /* when we were last queued to run */
800 };
801 #endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */
802 
803 #ifdef CONFIG_TASK_DELAY_ACCT
804 struct task_delay_info {
805         spinlock_t      lock;
806         unsigned int    flags;  /* Private per-task flags */
807 
808         /* For each stat XXX, add following, aligned appropriately
809          *
810          * struct timespec XXX_start, XXX_end;
811          * u64 XXX_delay;
812          * u32 XXX_count;
813          *
814          * Atomicity of updates to XXX_delay, XXX_count protected by
815          * single lock above (split into XXX_lock if contention is an issue).
816          */
817 
818         /*
819          * XXX_count is incremented on every XXX operation, the delay
820          * associated with the operation is added to XXX_delay.
821          * XXX_delay contains the accumulated delay time in nanoseconds.
822          */
823         struct timespec blkio_start, blkio_end; /* Shared by blkio, swapin */
824         u64 blkio_delay;        /* wait for sync block io completion */
825         u64 swapin_delay;       /* wait for swapin block io completion */
826         u32 blkio_count;        /* total count of the number of sync block */
827                                 /* io operations performed */
828         u32 swapin_count;       /* total count of the number of swapin block */
829                                 /* io operations performed */
830 
831         struct timespec freepages_start, freepages_end;
832         u64 freepages_delay;    /* wait for memory reclaim */
833         u32 freepages_count;    /* total count of memory reclaim */
834 };
835 #endif  /* CONFIG_TASK_DELAY_ACCT */
836 
837 static inline int sched_info_on(void)
838 {
839 #ifdef CONFIG_SCHEDSTATS
840         return 1;
841 #elif defined(CONFIG_TASK_DELAY_ACCT)
842         extern int delayacct_on;
843         return delayacct_on;
844 #else
845         return 0;
846 #endif
847 }
848 
849 enum cpu_idle_type {
850         CPU_IDLE,
851         CPU_NOT_IDLE,
852         CPU_NEWLY_IDLE,
853         CPU_MAX_IDLE_TYPES
854 };
855 
856 /*
857  * Increase resolution of cpu_power calculations
858  */
859 #define SCHED_POWER_SHIFT       10
860 #define SCHED_POWER_SCALE       (1L << SCHED_POWER_SHIFT)
861 
862 /*
863  * sched-domains (multiprocessor balancing) declarations:
864  */
865 #ifdef CONFIG_SMP
866 #define SD_LOAD_BALANCE         0x0001  /* Do load balancing on this domain. */
867 #define SD_BALANCE_NEWIDLE      0x0002  /* Balance when about to become idle */
868 #define SD_BALANCE_EXEC         0x0004  /* Balance on exec */
869 #define SD_BALANCE_FORK         0x0008  /* Balance on fork, clone */
870 #define SD_BALANCE_WAKE         0x0010  /* Balance on wakeup */
871 #define SD_WAKE_AFFINE          0x0020  /* Wake task to waking CPU */
872 #define SD_SHARE_CPUPOWER       0x0080  /* Domain members share cpu power */
873 #define SD_SHARE_PKG_RESOURCES  0x0200  /* Domain members share cpu pkg resources */
874 #define SD_SERIALIZE            0x0400  /* Only a single load balancing instance */
875 #define SD_ASYM_PACKING         0x0800  /* Place busy groups earlier in the domain */
876 #define SD_PREFER_SIBLING       0x1000  /* Prefer to place tasks in a sibling domain */
877 #define SD_OVERLAP              0x2000  /* sched_domains of this level overlap */
878 #define SD_NUMA                 0x4000  /* cross-node balancing */
879 
880 extern int __weak arch_sd_sibiling_asym_packing(void);
881 
882 struct sched_domain_attr {
883         int relax_domain_level;
884 };
885 
886 #define SD_ATTR_INIT    (struct sched_domain_attr) {    \
887         .relax_domain_level = -1,                       \
888 }
889 
890 extern int sched_domain_level_max;
891 
892 struct sched_group;
893 
894 struct sched_domain {
895         /* These fields must be setup */
896         struct sched_domain *parent;    /* top domain must be null terminated */
897         struct sched_domain *child;     /* bottom domain must be null terminated */
898         struct sched_group *groups;     /* the balancing groups of the domain */
899         unsigned long min_interval;     /* Minimum balance interval ms */
900         unsigned long max_interval;     /* Maximum balance interval ms */
901         unsigned int busy_factor;       /* less balancing by factor if busy */
902         unsigned int imbalance_pct;     /* No balance until over watermark */
903         unsigned int cache_nice_tries;  /* Leave cache hot tasks for # tries */
904         unsigned int busy_idx;
905         unsigned int idle_idx;
906         unsigned int newidle_idx;
907         unsigned int wake_idx;
908         unsigned int forkexec_idx;
909         unsigned int smt_gain;
910 
911         int nohz_idle;                  /* NOHZ IDLE status */
912         int flags;                      /* See SD_* */
913         int level;
914 
915         /* Runtime fields. */
916         unsigned long last_balance;     /* init to jiffies. units in jiffies */
917         unsigned int balance_interval;  /* initialise to 1. units in ms. */
918         unsigned int nr_balance_failed; /* initialise to 0 */
919 
920         /* idle_balance() stats */
921         u64 max_newidle_lb_cost;
922         unsigned long next_decay_max_lb_cost;
923 
924 #ifdef CONFIG_SCHEDSTATS
925         /* load_balance() stats */
926         unsigned int lb_count[CPU_MAX_IDLE_TYPES];
927         unsigned int lb_failed[CPU_MAX_IDLE_TYPES];
928         unsigned int lb_balanced[CPU_MAX_IDLE_TYPES];
929         unsigned int lb_imbalance[CPU_MAX_IDLE_TYPES];
930         unsigned int lb_gained[CPU_MAX_IDLE_TYPES];
931         unsigned int lb_hot_gained[CPU_MAX_IDLE_TYPES];
932         unsigned int lb_nobusyg[CPU_MAX_IDLE_TYPES];
933         unsigned int lb_nobusyq[CPU_MAX_IDLE_TYPES];
934 
935         /* Active load balancing */
936         unsigned int alb_count;
937         unsigned int alb_failed;
938         unsigned int alb_pushed;
939 
940         /* SD_BALANCE_EXEC stats */
941         unsigned int sbe_count;
942         unsigned int sbe_balanced;
943         unsigned int sbe_pushed;
944 
945         /* SD_BALANCE_FORK stats */
946         unsigned int sbf_count;
947         unsigned int sbf_balanced;
948         unsigned int sbf_pushed;
949 
950         /* try_to_wake_up() stats */
951         unsigned int ttwu_wake_remote;
952         unsigned int ttwu_move_affine;
953         unsigned int ttwu_move_balance;
954 #endif
955 #ifdef CONFIG_SCHED_DEBUG
956         char *name;
957 #endif
958         union {
959                 void *private;          /* used during construction */
960                 struct rcu_head rcu;    /* used during destruction */
961         };
962 
963         unsigned int span_weight;
964         /*
965          * Span of all CPUs in this domain.
966          *
967          * NOTE: this field is variable length. (Allocated dynamically
968          * by attaching extra space to the end of the structure,
969          * depending on how many CPUs the kernel has booted up with)
970          */
971         unsigned long span[0];
972 };
973 
974 static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
975 {
976         return to_cpumask(sd->span);
977 }
978 
979 extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
980                                     struct sched_domain_attr *dattr_new);
981 
982 /* Allocate an array of sched domains, for partition_sched_domains(). */
983 cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
984 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
985 
986 bool cpus_share_cache(int this_cpu, int that_cpu);
987 
988 #else /* CONFIG_SMP */
989 
990 struct sched_domain_attr;
991 
992 static inline void
993 partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
994                         struct sched_domain_attr *dattr_new)
995 {
996 }
997 
998 static inline bool cpus_share_cache(int this_cpu, int that_cpu)
999 {
1000         return true;
1001 }
1002 
1003 #endif  /* !CONFIG_SMP */
1004 
1005 
1006 struct io_context;                      /* See blkdev.h */
1007 
1008 
1009 #ifdef ARCH_HAS_PREFETCH_SWITCH_STACK
1010 extern void prefetch_stack(struct task_struct *t);
1011 #else
1012 static inline void prefetch_stack(struct task_struct *t) { }
1013 #endif
1014 
1015 struct audit_context;           /* See audit.c */
1016 struct mempolicy;
1017 struct pipe_inode_info;
1018 struct uts_namespace;
1019 
1020 struct load_weight {
1021         unsigned long weight;
1022         u32 inv_weight;
1023 };
1024 
1025 struct sched_avg {
1026         /*
1027          * These sums represent an infinite geometric series and so are bound
1028          * above by 1024/(1-y).  Thus we only need a u32 to store them for all
1029          * choices of y < 1-2^(-32)*1024.
1030          */
1031         u32 runnable_avg_sum, runnable_avg_period;
1032         u64 last_runnable_update;
1033         s64 decay_count;
1034         unsigned long load_avg_contrib;
1035 };
1036 
1037 #ifdef CONFIG_SCHEDSTATS
1038 struct sched_statistics {
1039         u64                     wait_start;
1040         u64                     wait_max;
1041         u64                     wait_count;
1042         u64                     wait_sum;
1043         u64                     iowait_count;
1044         u64                     iowait_sum;
1045 
1046         u64                     sleep_start;
1047         u64                     sleep_max;
1048         s64                     sum_sleep_runtime;
1049 
1050         u64                     block_start;
1051         u64                     block_max;
1052         u64                     exec_max;
1053         u64                     slice_max;
1054 
1055         u64                     nr_migrations_cold;
1056         u64                     nr_failed_migrations_affine;
1057         u64                     nr_failed_migrations_running;
1058         u64                     nr_failed_migrations_hot;
1059         u64                     nr_forced_migrations;
1060 
1061         u64                     nr_wakeups;
1062         u64                     nr_wakeups_sync;
1063         u64                     nr_wakeups_migrate;
1064         u64                     nr_wakeups_local;
1065         u64                     nr_wakeups_remote;
1066         u64                     nr_wakeups_affine;
1067         u64                     nr_wakeups_affine_attempts;
1068         u64                     nr_wakeups_passive;
1069         u64                     nr_wakeups_idle;
1070 };
1071 #endif
1072 
1073 struct sched_entity {
1074         struct load_weight      load;           /* for load-balancing */
1075         struct rb_node          run_node;
1076         struct list_head        group_node;
1077         unsigned int            on_rq;
1078 
1079         u64                     exec_start;
1080         u64                     sum_exec_runtime;
1081         u64                     vruntime;
1082         u64                     prev_sum_exec_runtime;
1083 
1084         u64                     nr_migrations;
1085 
1086 #ifdef CONFIG_SCHEDSTATS
1087         struct sched_statistics statistics;
1088 #endif
1089 
1090 #ifdef CONFIG_FAIR_GROUP_SCHED
1091         int                     depth;
1092         struct sched_entity     *parent;
1093         /* rq on which this entity is (to be) queued: */
1094         struct cfs_rq           *cfs_rq;
1095         /* rq "owned" by this entity/group: */
1096         struct cfs_rq           *my_q;
1097 #endif
1098 
1099 #ifdef CONFIG_SMP
1100         /* Per-entity load-tracking */
1101         struct sched_avg        avg;
1102 #endif
1103 };
1104 
1105 struct sched_rt_entity {
1106         struct list_head run_list;
1107         unsigned long timeout;
1108         unsigned long watchdog_stamp;
1109         unsigned int time_slice;
1110 
1111         struct sched_rt_entity *back;
1112 #ifdef CONFIG_RT_GROUP_SCHED
1113         struct sched_rt_entity  *parent;
1114         /* rq on which this entity is (to be) queued: */
1115         struct rt_rq            *rt_rq;
1116         /* rq "owned" by this entity/group: */
1117         struct rt_rq            *my_q;
1118 #endif
1119 };
1120 
1121 struct sched_dl_entity {
1122         struct rb_node  rb_node;
1123 
1124         /*
1125          * Original scheduling parameters. Copied here from sched_attr
1126          * during sched_setscheduler2(), they will remain the same until
1127          * the next sched_setscheduler2().
1128          */
1129         u64 dl_runtime;         /* maximum runtime for each instance    */
1130         u64 dl_deadline;        /* relative deadline of each instance   */
1131         u64 dl_period;          /* separation of two instances (period) */
1132         u64 dl_bw;              /* dl_runtime / dl_deadline             */
1133 
1134         /*
1135          * Actual scheduling parameters. Initialized with the values above,
1136          * they are continously updated during task execution. Note that
1137          * the remaining runtime could be < 0 in case we are in overrun.
1138          */
1139         s64 runtime;            /* remaining runtime for this instance  */
1140         u64 deadline;           /* absolute deadline for this instance  */
1141         unsigned int flags;     /* specifying the scheduler behaviour   */
1142 
1143         /*
1144          * Some bool flags:
1145          *
1146          * @dl_throttled tells if we exhausted the runtime. If so, the
1147          * task has to wait for a replenishment to be performed at the
1148          * next firing of dl_timer.
1149          *
1150          * @dl_new tells if a new instance arrived. If so we must
1151          * start executing it with full runtime and reset its absolute
1152          * deadline;
1153          *
1154          * @dl_boosted tells if we are boosted due to DI. If so we are
1155          * outside bandwidth enforcement mechanism (but only until we
1156          * exit the critical section);
1157          *
1158          * @dl_yielded tells if task gave up the cpu before consuming
1159          * all its available runtime during the last job.
1160          */
1161         int dl_throttled, dl_new, dl_boosted, dl_yielded;
1162 
1163         /*
1164          * Bandwidth enforcement timer. Each -deadline task has its
1165          * own bandwidth to be enforced, thus we need one timer per task.
1166          */
1167         struct hrtimer dl_timer;
1168 };
1169 
1170 struct rcu_node;
1171 
1172 enum perf_event_task_context {
1173         perf_invalid_context = -1,
1174         perf_hw_context = 0,
1175         perf_sw_context,
1176         perf_nr_task_contexts,
1177 };
1178 
1179 struct task_struct {
1180         volatile long state;    /* -1 unrunnable, 0 runnable, >0 stopped */
1181         void *stack;
1182         atomic_t usage;
1183         unsigned int flags;     /* per process flags, defined below */
1184         unsigned int ptrace;
1185 
1186 #ifdef CONFIG_SMP
1187         struct llist_node wake_entry;
1188         int on_cpu;
1189         struct task_struct *last_wakee;
1190         unsigned long wakee_flips;
1191         unsigned long wakee_flip_decay_ts;
1192 
1193         int wake_cpu;
1194 #endif
1195         int on_rq;
1196 
1197         int prio, static_prio, normal_prio;
1198         unsigned int rt_priority;
1199         const struct sched_class *sched_class;
1200         struct sched_entity se;
1201         struct sched_rt_entity rt;
1202 #ifdef CONFIG_CGROUP_SCHED
1203         struct task_group *sched_task_group;
1204 #endif
1205         struct sched_dl_entity dl;
1206 
1207 #ifdef CONFIG_PREEMPT_NOTIFIERS
1208         /* list of struct preempt_notifier: */
1209         struct hlist_head preempt_notifiers;
1210 #endif
1211 
1212 #ifdef CONFIG_BLK_DEV_IO_TRACE
1213         unsigned int btrace_seq;
1214 #endif
1215 
1216         unsigned int policy;
1217         int nr_cpus_allowed;
1218         cpumask_t cpus_allowed;
1219 
1220 #ifdef CONFIG_PREEMPT_RCU
1221         int rcu_read_lock_nesting;
1222         char rcu_read_unlock_special;
1223         struct list_head rcu_node_entry;
1224 #endif /* #ifdef CONFIG_PREEMPT_RCU */
1225 #ifdef CONFIG_TREE_PREEMPT_RCU
1226         struct rcu_node *rcu_blocked_node;
1227 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
1228 #ifdef CONFIG_RCU_BOOST
1229         struct rt_mutex *rcu_boost_mutex;
1230 #endif /* #ifdef CONFIG_RCU_BOOST */
1231 
1232 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1233         struct sched_info sched_info;
1234 #endif
1235 
1236         struct list_head tasks;
1237 #ifdef CONFIG_SMP
1238         struct plist_node pushable_tasks;
1239         struct rb_node pushable_dl_tasks;
1240 #endif
1241 
1242         struct mm_struct *mm, *active_mm;
1243 #ifdef CONFIG_COMPAT_BRK
1244         unsigned brk_randomized:1;
1245 #endif
1246         /* per-thread vma caching */
1247         u32 vmacache_seqnum;
1248         struct vm_area_struct *vmacache[VMACACHE_SIZE];
1249 #if defined(SPLIT_RSS_COUNTING)
1250         struct task_rss_stat    rss_stat;
1251 #endif
1252 /* task state */
1253         int exit_state;
1254         int exit_code, exit_signal;
1255         int pdeath_signal;  /*  The signal sent when the parent dies  */
1256         unsigned int jobctl;    /* JOBCTL_*, siglock protected */
1257 
1258         /* Used for emulating ABI behavior of previous Linux versions */
1259         unsigned int personality;
1260 
1261         unsigned in_execve:1;   /* Tell the LSMs that the process is doing an
1262                                  * execve */
1263         unsigned in_iowait:1;
1264 
1265         /* task may not gain privileges */
1266         unsigned no_new_privs:1;
1267 
1268         /* Revert to default priority/policy when forking */
1269         unsigned sched_reset_on_fork:1;
1270         unsigned sched_contributes_to_load:1;
1271 
1272         pid_t pid;
1273         pid_t tgid;
1274 
1275 #ifdef CONFIG_CC_STACKPROTECTOR
1276         /* Canary value for the -fstack-protector gcc feature */
1277         unsigned long stack_canary;
1278 #endif
1279         /*
1280          * pointers to (original) parent process, youngest child, younger sibling,
1281          * older sibling, respectively.  (p->father can be replaced with
1282          * p->real_parent->pid)
1283          */
1284         struct task_struct __rcu *real_parent; /* real parent process */
1285         struct task_struct __rcu *parent; /* recipient of SIGCHLD, wait4() reports */
1286         /*
1287          * children/sibling forms the list of my natural children
1288          */
1289         struct list_head children;      /* list of my children */
1290         struct list_head sibling;       /* linkage in my parent's children list */
1291         struct task_struct *group_leader;       /* threadgroup leader */
1292 
1293         /*
1294          * ptraced is the list of tasks this task is using ptrace on.
1295          * This includes both natural children and PTRACE_ATTACH targets.
1296          * p->ptrace_entry is p's link on the p->parent->ptraced list.
1297          */
1298         struct list_head ptraced;
1299         struct list_head ptrace_entry;
1300 
1301         /* PID/PID hash table linkage. */
1302         struct pid_link pids[PIDTYPE_MAX];
1303         struct list_head thread_group;
1304         struct list_head thread_node;
1305 
1306         struct completion *vfork_done;          /* for vfork() */
1307         int __user *set_child_tid;              /* CLONE_CHILD_SETTID */
1308         int __user *clear_child_tid;            /* CLONE_CHILD_CLEARTID */
1309 
1310         cputime_t utime, stime, utimescaled, stimescaled;
1311         cputime_t gtime;
1312 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
1313         struct cputime prev_cputime;
1314 #endif
1315 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1316         seqlock_t vtime_seqlock;
1317         unsigned long long vtime_snap;
1318         enum {
1319                 VTIME_SLEEPING = 0,
1320                 VTIME_USER,
1321                 VTIME_SYS,
1322         } vtime_snap_whence;
1323 #endif
1324         unsigned long nvcsw, nivcsw; /* context switch counts */
1325         struct timespec start_time;             /* monotonic time */
1326         struct timespec real_start_time;        /* boot based time */
1327 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
1328         unsigned long min_flt, maj_flt;
1329 
1330         struct task_cputime cputime_expires;
1331         struct list_head cpu_timers[3];
1332 
1333 /* process credentials */
1334         const struct cred __rcu *real_cred; /* objective and real subjective task
1335                                          * credentials (COW) */
1336         const struct cred __rcu *cred;  /* effective (overridable) subjective task
1337                                          * credentials (COW) */
1338         char comm[TASK_COMM_LEN]; /* executable name excluding path
1339                                      - access with [gs]et_task_comm (which lock
1340                                        it with task_lock())
1341                                      - initialized normally by setup_new_exec */
1342 /* file system info */
1343         int link_count, total_link_count;
1344 #ifdef CONFIG_SYSVIPC
1345 /* ipc stuff */
1346         struct sysv_sem sysvsem;
1347 #endif
1348 #ifdef CONFIG_DETECT_HUNG_TASK
1349 /* hung task detection */
1350         unsigned long last_switch_count;
1351 #endif
1352 /* CPU-specific state of this task */
1353         struct thread_struct thread;
1354 /* filesystem information */
1355         struct fs_struct *fs;
1356 /* open file information */
1357         struct files_struct *files;
1358 /* namespaces */
1359         struct nsproxy *nsproxy;
1360 /* signal handlers */
1361         struct signal_struct *signal;
1362         struct sighand_struct *sighand;
1363 
1364         sigset_t blocked, real_blocked;
1365         sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */
1366         struct sigpending pending;
1367 
1368         unsigned long sas_ss_sp;
1369         size_t sas_ss_size;
1370         int (*notifier)(void *priv);
1371         void *notifier_data;
1372         sigset_t *notifier_mask;
1373         struct callback_head *task_works;
1374 
1375         struct audit_context *audit_context;
1376 #ifdef CONFIG_AUDITSYSCALL
1377         kuid_t loginuid;
1378         unsigned int sessionid;
1379 #endif
1380         struct seccomp seccomp;
1381 
1382 /* Thread group tracking */
1383         u32 parent_exec_id;
1384         u32 self_exec_id;
1385 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed,
1386  * mempolicy */
1387         spinlock_t alloc_lock;
1388 
1389         /* Protection of the PI data structures: */
1390         raw_spinlock_t pi_lock;
1391 
1392 #ifdef CONFIG_RT_MUTEXES
1393         /* PI waiters blocked on a rt_mutex held by this task */
1394         struct rb_root pi_waiters;
1395         struct rb_node *pi_waiters_leftmost;
1396         /* Deadlock detection and priority inheritance handling */
1397         struct rt_mutex_waiter *pi_blocked_on;
1398         /* Top pi_waiters task */
1399         struct task_struct *pi_top_task;
1400 #endif
1401 
1402 #ifdef CONFIG_DEBUG_MUTEXES
1403         /* mutex deadlock detection */
1404         struct mutex_waiter *blocked_on;
1405 #endif
1406 #ifdef CONFIG_TRACE_IRQFLAGS
1407         unsigned int irq_events;
1408         unsigned long hardirq_enable_ip;
1409         unsigned long hardirq_disable_ip;
1410         unsigned int hardirq_enable_event;
1411         unsigned int hardirq_disable_event;
1412         int hardirqs_enabled;
1413         int hardirq_context;
1414         unsigned long softirq_disable_ip;
1415         unsigned long softirq_enable_ip;
1416         unsigned int softirq_disable_event;
1417         unsigned int softirq_enable_event;
1418         int softirqs_enabled;
1419         int softirq_context;
1420 #endif
1421 #ifdef CONFIG_LOCKDEP
1422 # define MAX_LOCK_DEPTH 48UL
1423         u64 curr_chain_key;
1424         int lockdep_depth;
1425         unsigned int lockdep_recursion;
1426         struct held_lock held_locks[MAX_LOCK_DEPTH];
1427         gfp_t lockdep_reclaim_gfp;
1428 #endif
1429 
1430 /* journalling filesystem info */
1431         void *journal_info;
1432 
1433 /* stacked block device info */
1434         struct bio_list *bio_list;
1435 
1436 #ifdef CONFIG_BLOCK
1437 /* stack plugging */
1438         struct blk_plug *plug;
1439 #endif
1440 
1441 /* VM state */
1442         struct reclaim_state *reclaim_state;
1443 
1444         struct backing_dev_info *backing_dev_info;
1445 
1446         struct io_context *io_context;
1447 
1448         unsigned long ptrace_message;
1449         siginfo_t *last_siginfo; /* For ptrace use.  */
1450         struct task_io_accounting ioac;
1451 #if defined(CONFIG_TASK_XACCT)
1452         u64 acct_rss_mem1;      /* accumulated rss usage */
1453         u64 acct_vm_mem1;       /* accumulated virtual memory usage */
1454         cputime_t acct_timexpd; /* stime + utime since last update */
1455 #endif
1456 #ifdef CONFIG_CPUSETS
1457         nodemask_t mems_allowed;        /* Protected by alloc_lock */
1458         seqcount_t mems_allowed_seq;    /* Seqence no to catch updates */
1459         int cpuset_mem_spread_rotor;
1460         int cpuset_slab_spread_rotor;
1461 #endif
1462 #ifdef CONFIG_CGROUPS
1463         /* Control Group info protected by css_set_lock */
1464         struct css_set __rcu *cgroups;
1465         /* cg_list protected by css_set_lock and tsk->alloc_lock */
1466         struct list_head cg_list;
1467 #endif
1468 #ifdef CONFIG_FUTEX
1469         struct robust_list_head __user *robust_list;
1470 #ifdef CONFIG_COMPAT
1471         struct compat_robust_list_head __user *compat_robust_list;
1472 #endif
1473         struct list_head pi_state_list;
1474         struct futex_pi_state *pi_state_cache;
1475 #endif
1476 #ifdef CONFIG_PERF_EVENTS
1477         struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
1478         struct mutex perf_event_mutex;
1479         struct list_head perf_event_list;
1480 #endif
1481 #ifdef CONFIG_DEBUG_PREEMPT
1482         unsigned long preempt_disable_ip;
1483 #endif
1484 #ifdef CONFIG_NUMA
1485         struct mempolicy *mempolicy;    /* Protected by alloc_lock */
1486         short il_next;
1487         short pref_node_fork;
1488 #endif
1489 #ifdef CONFIG_NUMA_BALANCING
1490         int numa_scan_seq;
1491         unsigned int numa_scan_period;
1492         unsigned int numa_scan_period_max;
1493         int numa_preferred_nid;
1494         unsigned long numa_migrate_retry;
1495         u64 node_stamp;                 /* migration stamp  */
1496         u64 last_task_numa_placement;
1497         u64 last_sum_exec_runtime;
1498         struct callback_head numa_work;
1499 
1500         struct list_head numa_entry;
1501         struct numa_group *numa_group;
1502 
1503         /*
1504          * Exponential decaying average of faults on a per-node basis.
1505          * Scheduling placement decisions are made based on the these counts.
1506          * The values remain static for the duration of a PTE scan
1507          */
1508         unsigned long *numa_faults_memory;
1509         unsigned long total_numa_faults;
1510 
1511         /*
1512          * numa_faults_buffer records faults per node during the current
1513          * scan window. When the scan completes, the counts in
1514          * numa_faults_memory decay and these values are copied.
1515          */
1516         unsigned long *numa_faults_buffer_memory;
1517 
1518         /*
1519          * Track the nodes the process was running on when a NUMA hinting
1520          * fault was incurred.
1521          */
1522         unsigned long *numa_faults_cpu;
1523         unsigned long *numa_faults_buffer_cpu;
1524 
1525         /*
1526          * numa_faults_locality tracks if faults recorded during the last
1527          * scan window were remote/local. The task scan period is adapted
1528          * based on the locality of the faults with different weights
1529          * depending on whether they were shared or private faults
1530          */
1531         unsigned long numa_faults_locality[2];
1532 
1533         unsigned long numa_pages_migrated;
1534 #endif /* CONFIG_NUMA_BALANCING */
1535 
1536         struct rcu_head rcu;
1537 
1538         /*
1539          * cache last used pipe for splice
1540          */
1541         struct pipe_inode_info *splice_pipe;
1542 
1543         struct page_frag task_frag;
1544 
1545 #ifdef  CONFIG_TASK_DELAY_ACCT
1546         struct task_delay_info *delays;
1547 #endif
1548 #ifdef CONFIG_FAULT_INJECTION
1549         int make_it_fail;
1550 #endif
1551         /*
1552          * when (nr_dirtied >= nr_dirtied_pause), it's time to call
1553          * balance_dirty_pages() for some dirty throttling pause
1554          */
1555         int nr_dirtied;
1556         int nr_dirtied_pause;
1557         unsigned long dirty_paused_when; /* start of a write-and-pause period */
1558 
1559 #ifdef CONFIG_LATENCYTOP
1560         int latency_record_count;
1561         struct latency_record latency_record[LT_SAVECOUNT];
1562 #endif
1563         /*
1564          * time slack values; these are used to round up poll() and
1565          * select() etc timeout values. These are in nanoseconds.
1566          */
1567         unsigned long timer_slack_ns;
1568         unsigned long default_timer_slack_ns;
1569 
1570 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1571         /* Index of current stored address in ret_stack */
1572         int curr_ret_stack;
1573         /* Stack of return addresses for return function tracing */
1574         struct ftrace_ret_stack *ret_stack;
1575         /* time stamp for last schedule */
1576         unsigned long long ftrace_timestamp;
1577         /*
1578          * Number of functions that haven't been traced
1579          * because of depth overrun.
1580          */
1581         atomic_t trace_overrun;
1582         /* Pause for the tracing */
1583         atomic_t tracing_graph_pause;
1584 #endif
1585 #ifdef CONFIG_TRACING
1586         /* state flags for use by tracers */
1587         unsigned long trace;
1588         /* bitmask and counter of trace recursion */
1589         unsigned long trace_recursion;
1590 #endif /* CONFIG_TRACING */
1591 #ifdef CONFIG_MEMCG /* memcg uses this to do batch job */
1592         struct memcg_batch_info {
1593                 int do_batch;   /* incremented when batch uncharge started */
1594                 struct mem_cgroup *memcg; /* target memcg of uncharge */
1595                 unsigned long nr_pages; /* uncharged usage */
1596                 unsigned long memsw_nr_pages; /* uncharged mem+swap usage */
1597         } memcg_batch;
1598         unsigned int memcg_kmem_skip_account;
1599         struct memcg_oom_info {
1600                 struct mem_cgroup *memcg;
1601                 gfp_t gfp_mask;
1602                 int order;
1603                 unsigned int may_oom:1;
1604         } memcg_oom;
1605 #endif
1606 #ifdef CONFIG_UPROBES
1607         struct uprobe_task *utask;
1608 #endif
1609 #if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
1610         unsigned int    sequential_io;
1611         unsigned int    sequential_io_avg;
1612 #endif
1613 };
1614 
1615 /* Future-safe accessor for struct task_struct's cpus_allowed. */
1616 #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
1617 
1618 #define TNF_MIGRATED    0x01
1619 #define TNF_NO_GROUP    0x02
1620 #define TNF_SHARED      0x04
1621 #define TNF_FAULT_LOCAL 0x08
1622 
1623 #ifdef CONFIG_NUMA_BALANCING
1624 extern void task_numa_fault(int last_node, int node, int pages, int flags);
1625 extern pid_t task_numa_group_id(struct task_struct *p);
1626 extern void set_numabalancing_state(bool enabled);
1627 extern void task_numa_free(struct task_struct *p);
1628 extern bool should_numa_migrate_memory(struct task_struct *p, struct page *page,
1629                                         int src_nid, int dst_cpu);
1630 #else
1631 static inline void task_numa_fault(int last_node, int node, int pages,
1632                                    int flags)
1633 {
1634 }
1635 static inline pid_t task_numa_group_id(struct task_struct *p)
1636 {
1637         return 0;
1638 }
1639 static inline void set_numabalancing_state(bool enabled)
1640 {
1641 }
1642 static inline void task_numa_free(struct task_struct *p)
1643 {
1644 }
1645 static inline bool should_numa_migrate_memory(struct task_struct *p,
1646                                 struct page *page, int src_nid, int dst_cpu)
1647 {
1648         return true;
1649 }
1650 #endif
1651 
1652 static inline struct pid *task_pid(struct task_struct *task)
1653 {
1654         return task->pids[PIDTYPE_PID].pid;
1655 }
1656 
1657 static inline struct pid *task_tgid(struct task_struct *task)
1658 {
1659         return task->group_leader->pids[PIDTYPE_PID].pid;
1660 }
1661 
1662 /*
1663  * Without tasklist or rcu lock it is not safe to dereference
1664  * the result of task_pgrp/task_session even if task == current,
1665  * we can race with another thread doing sys_setsid/sys_setpgid.
1666  */
1667 static inline struct pid *task_pgrp(struct task_struct *task)
1668 {
1669         return task->group_leader->pids[PIDTYPE_PGID].pid;
1670 }
1671 
1672 static inline struct pid *task_session(struct task_struct *task)
1673 {
1674         return task->group_leader->pids[PIDTYPE_SID].pid;
1675 }
1676 
1677 struct pid_namespace;
1678 
1679 /*
1680  * the helpers to get the task's different pids as they are seen
1681  * from various namespaces
1682  *
1683  * task_xid_nr()     : global id, i.e. the id seen from the init namespace;
1684  * task_xid_vnr()    : virtual id, i.e. the id seen from the pid namespace of
1685  *                     current.
1686  * task_xid_nr_ns()  : id seen from the ns specified;
1687  *
1688  * set_task_vxid()   : assigns a virtual id to a task;
1689  *
1690  * see also pid_nr() etc in include/linux/pid.h
1691  */
1692 pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
1693                         struct pid_namespace *ns);
1694 
1695 static inline pid_t task_pid_nr(struct task_struct *tsk)
1696 {
1697         return tsk->pid;
1698 }
1699 
1700 static inline pid_t task_pid_nr_ns(struct task_struct *tsk,
1701                                         struct pid_namespace *ns)
1702 {
1703         return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1704 }
1705 
1706 static inline pid_t task_pid_vnr(struct task_struct *tsk)
1707 {
1708         return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1709 }
1710 
1711 
1712 static inline pid_t task_tgid_nr(struct task_struct *tsk)
1713 {
1714         return tsk->tgid;
1715 }
1716 
1717 pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);
1718 
1719 static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1720 {
1721         return pid_vnr(task_tgid(tsk));
1722 }
1723 
1724 
1725 static inline int pid_alive(const struct task_struct *p);
1726 static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)
1727 {
1728         pid_t pid = 0;
1729 
1730         rcu_read_lock();
1731         if (pid_alive(tsk))
1732                 pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
1733         rcu_read_unlock();
1734 
1735         return pid;
1736 }
1737 
1738 static inline pid_t task_ppid_nr(const struct task_struct *tsk)
1739 {
1740         return task_ppid_nr_ns(tsk, &init_pid_ns);
1741 }
1742 
1743 static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,
1744                                         struct pid_namespace *ns)
1745 {
1746         return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1747 }
1748 
1749 static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1750 {
1751         return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1752 }
1753 
1754 
1755 static inline pid_t task_session_nr_ns(struct task_struct *tsk,
1756                                         struct pid_namespace *ns)
1757 {
1758         return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1759 }
1760 
1761 static inline pid_t task_session_vnr(struct task_struct *tsk)
1762 {
1763         return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1764 }
1765 
1766 /* obsolete, do not use */
1767 static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1768 {
1769         return task_pgrp_nr_ns(tsk, &init_pid_ns);
1770 }
1771 
1772 /**
1773  * pid_alive - check that a task structure is not stale
1774  * @p: Task structure to be checked.
1775  *
1776  * Test if a process is not yet dead (at most zombie state)
1777  * If pid_alive fails, then pointers within the task structure
1778  * can be stale and must not be dereferenced.
1779  *
1780  * Return: 1 if the process is alive. 0 otherwise.
1781  */
1782 static inline int pid_alive(const struct task_struct *p)
1783 {
1784         return p->pids[PIDTYPE_PID].pid != NULL;
1785 }
1786 
1787 /**
1788  * is_global_init - check if a task structure is init
1789  * @tsk: Task structure to be checked.
1790  *
1791  * Check if a task structure is the first user space task the kernel created.
1792  *
1793  * Return: 1 if the task structure is init. 0 otherwise.
1794  */
1795 static inline int is_global_init(struct task_struct *tsk)
1796 {
1797         return tsk->pid == 1;
1798 }
1799 
1800 extern struct pid *cad_pid;
1801 
1802 extern void free_task(struct task_struct *tsk);
1803 #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
1804 
1805 extern void __put_task_struct(struct task_struct *t);
1806 
1807 static inline void put_task_struct(struct task_struct *t)
1808 {
1809         if (atomic_dec_and_test(&t->usage))
1810                 __put_task_struct(t);
1811 }
1812 
1813 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1814 extern void task_cputime(struct task_struct *t,
1815                          cputime_t *utime, cputime_t *stime);
1816 extern void task_cputime_scaled(struct task_struct *t,
1817                                 cputime_t *utimescaled, cputime_t *stimescaled);
1818 extern cputime_t task_gtime(struct task_struct *t);
1819 #else
1820 static inline void task_cputime(struct task_struct *t,
1821                                 cputime_t *utime, cputime_t *stime)
1822 {
1823         if (utime)
1824                 *utime = t->utime;
1825         if (stime)
1826                 *stime = t->stime;
1827 }
1828 
1829 static inline void task_cputime_scaled(struct task_struct *t,
1830                                        cputime_t *utimescaled,
1831                                        cputime_t *stimescaled)
1832 {
1833         if (utimescaled)
1834                 *utimescaled = t->utimescaled;
1835         if (stimescaled)
1836                 *stimescaled = t->stimescaled;
1837 }
1838 
1839 static inline cputime_t task_gtime(struct task_struct *t)
1840 {
1841         return t->gtime;
1842 }
1843 #endif
1844 extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
1845 extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
1846 
1847 /*
1848  * Per process flags
1849  */
1850 #define PF_EXITING      0x00000004      /* getting shut down */
1851 #define PF_EXITPIDONE   0x00000008      /* pi exit done on shut down */
1852 #define PF_VCPU         0x00000010      /* I'm a virtual CPU */
1853 #define PF_WQ_WORKER    0x00000020      /* I'm a workqueue worker */
1854 #define PF_FORKNOEXEC   0x00000040      /* forked but didn't exec */
1855 #define PF_MCE_PROCESS  0x00000080      /* process policy on mce errors */
1856 #define PF_SUPERPRIV    0x00000100      /* used super-user privileges */
1857 #define PF_DUMPCORE     0x00000200      /* dumped core */
1858 #define PF_SIGNALED     0x00000400      /* killed by a signal */
1859 #define PF_MEMALLOC     0x00000800      /* Allocating memory */
1860 #define PF_NPROC_EXCEEDED 0x00001000    /* set_user noticed that RLIMIT_NPROC was exceeded */
1861 #define PF_USED_MATH    0x00002000      /* if unset the fpu must be initialized before use */
1862 #define PF_USED_ASYNC   0x00004000      /* used async_schedule*(), used by module init */
1863 #define PF_NOFREEZE     0x00008000      /* this thread should not be frozen */
1864 #define PF_FROZEN       0x00010000      /* frozen for system suspend */
1865 #define PF_FSTRANS      0x00020000      /* inside a filesystem transaction */
1866 #define PF_KSWAPD       0x00040000      /* I am kswapd */
1867 #define PF_MEMALLOC_NOIO 0x00080000     /* Allocating memory without IO involved */
1868 #define PF_LESS_THROTTLE 0x00100000     /* Throttle me less: I clean memory */
1869 #define PF_KTHREAD      0x00200000      /* I am a kernel thread */
1870 #define PF_RANDOMIZE    0x00400000      /* randomize virtual address space */
1871 #define PF_SWAPWRITE    0x00800000      /* Allowed to write to swap */
1872 #define PF_SPREAD_PAGE  0x01000000      /* Spread page cache over cpuset */
1873 #define PF_SPREAD_SLAB  0x02000000      /* Spread some slab caches over cpuset */
1874 #define PF_NO_SETAFFINITY 0x04000000    /* Userland is not allowed to meddle with cpus_allowed */
1875 #define PF_MCE_EARLY    0x08000000      /* Early kill for mce process policy */
1876 #define PF_MUTEX_TESTER 0x20000000      /* Thread belongs to the rt mutex tester */
1877 #define PF_FREEZER_SKIP 0x40000000      /* Freezer should not count it as freezable */
1878 #define PF_SUSPEND_TASK 0x80000000      /* this thread called freeze_processes and should not be frozen */
1879 
1880 /*
1881  * Only the _current_ task can read/write to tsk->flags, but other
1882  * tasks can access tsk->flags in readonly mode for example
1883  * with tsk_used_math (like during threaded core dumping).
1884  * There is however an exception to this rule during ptrace
1885  * or during fork: the ptracer task is allowed to write to the
1886  * child->flags of its traced child (same goes for fork, the parent
1887  * can write to the child->flags), because we're guaranteed the
1888  * child is not running and in turn not changing child->flags
1889  * at the same time the parent does it.
1890  */
1891 #define clear_stopped_child_used_math(child) do { (child)->flags &= ~PF_USED_MATH; } while (0)
1892 #define set_stopped_child_used_math(child) do { (child)->flags |= PF_USED_MATH; } while (0)
1893 #define clear_used_math() clear_stopped_child_used_math(current)
1894 #define set_used_math() set_stopped_child_used_math(current)
1895 #define conditional_stopped_child_used_math(condition, child) \
1896         do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1897 #define conditional_used_math(condition) \
1898         conditional_stopped_child_used_math(condition, current)
1899 #define copy_to_stopped_child_used_math(child) \
1900         do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1901 /* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1902 #define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
1903 #define used_math() tsk_used_math(current)
1904 
1905 /* __GFP_IO isn't allowed if PF_MEMALLOC_NOIO is set in current->flags */
1906 static inline gfp_t memalloc_noio_flags(gfp_t flags)
1907 {
1908         if (unlikely(current->flags & PF_MEMALLOC_NOIO))
1909                 flags &= ~__GFP_IO;
1910         return flags;
1911 }
1912 
1913 static inline unsigned int memalloc_noio_save(void)
1914 {
1915         unsigned int flags = current->flags & PF_MEMALLOC_NOIO;
1916         current->flags |= PF_MEMALLOC_NOIO;
1917         return flags;
1918 }
1919 
1920 static inline void memalloc_noio_restore(unsigned int flags)
1921 {
1922         current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
1923 }
1924 
1925 /*
1926  * task->jobctl flags
1927  */
1928 #define JOBCTL_STOP_SIGMASK     0xffff  /* signr of the last group stop */
1929 
1930 #define JOBCTL_STOP_DEQUEUED_BIT 16     /* stop signal dequeued */
1931 #define JOBCTL_STOP_PENDING_BIT 17      /* task should stop for group stop */
1932 #define JOBCTL_STOP_CONSUME_BIT 18      /* consume group stop count */
1933 #define JOBCTL_TRAP_STOP_BIT    19      /* trap for STOP */
1934 #define JOBCTL_TRAP_NOTIFY_BIT  20      /* trap for NOTIFY */
1935 #define JOBCTL_TRAPPING_BIT     21      /* switching to TRACED */
1936 #define JOBCTL_LISTENING_BIT    22      /* ptracer is listening for events */
1937 
1938 #define JOBCTL_STOP_DEQUEUED    (1 << JOBCTL_STOP_DEQUEUED_BIT)
1939 #define JOBCTL_STOP_PENDING     (1 << JOBCTL_STOP_PENDING_BIT)
1940 #define JOBCTL_STOP_CONSUME     (1 << JOBCTL_STOP_CONSUME_BIT)
1941 #define JOBCTL_TRAP_STOP        (1 << JOBCTL_TRAP_STOP_BIT)
1942 #define JOBCTL_TRAP_NOTIFY      (1 << JOBCTL_TRAP_NOTIFY_BIT)
1943 #define JOBCTL_TRAPPING         (1 << JOBCTL_TRAPPING_BIT)
1944 #define JOBCTL_LISTENING        (1 << JOBCTL_LISTENING_BIT)
1945 
1946 #define JOBCTL_TRAP_MASK        (JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY)
1947 #define JOBCTL_PENDING_MASK     (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK)
1948 
1949 extern bool task_set_jobctl_pending(struct task_struct *task,
1950                                     unsigned int mask);
1951 extern void task_clear_jobctl_trapping(struct task_struct *task);
1952 extern void task_clear_jobctl_pending(struct task_struct *task,
1953                                       unsigned int mask);
1954 
1955 #ifdef CONFIG_PREEMPT_RCU
1956 
1957 #define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
1958 #define RCU_READ_UNLOCK_NEED_QS (1 << 1) /* RCU core needs CPU response. */
1959 
1960 static inline void rcu_copy_process(struct task_struct *p)
1961 {
1962         p->rcu_read_lock_nesting = 0;
1963         p->rcu_read_unlock_special = 0;
1964 #ifdef CONFIG_TREE_PREEMPT_RCU
1965         p->rcu_blocked_node = NULL;
1966 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
1967 #ifdef CONFIG_RCU_BOOST
1968         p->rcu_boost_mutex = NULL;
1969 #endif /* #ifdef CONFIG_RCU_BOOST */
1970         INIT_LIST_HEAD(&p->rcu_node_entry);
1971 }
1972 
1973 #else
1974 
1975 static inline void rcu_copy_process(struct task_struct *p)
1976 {
1977 }
1978 
1979 #endif
1980 
1981 static inline void tsk_restore_flags(struct task_struct *task,
1982                                 unsigned long orig_flags, unsigned long flags)
1983 {
1984         task->flags &= ~flags;
1985         task->flags |= orig_flags & flags;
1986 }
1987 
1988 #ifdef CONFIG_SMP
1989 extern void do_set_cpus_allowed(struct task_struct *p,
1990                                const struct cpumask *new_mask);
1991 
1992 extern int set_cpus_allowed_ptr(struct task_struct *p,
1993                                 const struct cpumask *new_mask);
1994 #else
1995 static inline void do_set_cpus_allowed(struct task_struct *p,
1996                                       const struct cpumask *new_mask)
1997 {
1998 }
1999 static inline int set_cpus_allowed_ptr(struct task_struct *p,
2000                                        const struct cpumask *new_mask)
2001 {
2002         if (!cpumask_test_cpu(0, new_mask))
2003                 return -EINVAL;
2004         return 0;
2005 }
2006 #endif
2007 
2008 #ifdef CONFIG_NO_HZ_COMMON
2009 void calc_load_enter_idle(void);
2010 void calc_load_exit_idle(void);
2011 #else
2012 static inline void calc_load_enter_idle(void) { }
2013 static inline void calc_load_exit_idle(void) { }
2014 #endif /* CONFIG_NO_HZ_COMMON */
2015 
2016 #ifndef CONFIG_CPUMASK_OFFSTACK
2017 static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
2018 {
2019         return set_cpus_allowed_ptr(p, &new_mask);
2020 }
2021 #endif
2022 
2023 /*
2024  * Do not use outside of architecture code which knows its limitations.
2025  *
2026  * sched_clock() has no promise of monotonicity or bounded drift between
2027  * CPUs, use (which you should not) requires disabling IRQs.
2028  *
2029  * Please use one of the three interfaces below.
2030  */
2031 extern unsigned long long notrace sched_clock(void);
2032 /*
2033  * See the comment in kernel/sched/clock.c
2034  */
2035 extern u64 cpu_clock(int cpu);
2036 extern u64 local_clock(void);
2037 extern u64 sched_clock_cpu(int cpu);
2038 
2039 
2040 extern void sched_clock_init(void);
2041 
2042 #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2043 static inline void sched_clock_tick(void)
2044 {
2045 }
2046 
2047 static inline void sched_clock_idle_sleep_event(void)
2048 {
2049 }
2050 
2051 static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
2052 {
2053 }
2054 #else
2055 /*
2056  * Architectures can set this to 1 if they have specified
2057  * CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
2058  * but then during bootup it turns out that sched_clock()
2059  * is reliable after all:
2060  */
2061 extern int sched_clock_stable(void);
2062 extern void set_sched_clock_stable(void);
2063 extern void clear_sched_clock_stable(void);
2064 
2065 extern void sched_clock_tick(void);
2066 extern void sched_clock_idle_sleep_event(void);
2067 extern void sched_clock_idle_wakeup_event(u64 delta_ns);
2068 #endif
2069 
2070 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2071 /*
2072  * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
2073  * The reason for this explicit opt-in is not to have perf penalty with
2074  * slow sched_clocks.
2075  */
2076 extern void enable_sched_clock_irqtime(void);
2077 extern void disable_sched_clock_irqtime(void);
2078 #else
2079 static inline void enable_sched_clock_irqtime(void) {}
2080 static inline void disable_sched_clock_irqtime(void) {}
2081 #endif
2082 
2083 extern unsigned long long
2084 task_sched_runtime(struct task_struct *task);
2085 
2086 /* sched_exec is called by processes performing an exec */
2087 #ifdef CONFIG_SMP
2088 extern void sched_exec(void);
2089 #else
2090 #define sched_exec()   {}
2091 #endif
2092 
2093 extern void sched_clock_idle_sleep_event(void);
2094 extern void sched_clock_idle_wakeup_event(u64 delta_ns);
2095 
2096 #ifdef CONFIG_HOTPLUG_CPU
2097 extern void idle_task_exit(void);
2098 #else
2099 static inline void idle_task_exit(void) {}
2100 #endif
2101 
2102 #if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
2103 extern void wake_up_nohz_cpu(int cpu);
2104 #else
2105 static inline void wake_up_nohz_cpu(int cpu) { }
2106 #endif
2107 
2108 #ifdef CONFIG_NO_HZ_FULL
2109 extern bool sched_can_stop_tick(void);
2110 extern u64 scheduler_tick_max_deferment(void);
2111 #else
2112 static inline bool sched_can_stop_tick(void) { return false; }
2113 #endif
2114 
2115 #ifdef CONFIG_SCHED_AUTOGROUP
2116 extern void sched_autogroup_create_attach(struct task_struct *p);
2117 extern void sched_autogroup_detach(struct task_struct *p);
2118 extern void sched_autogroup_fork(struct signal_struct *sig);
2119 extern void sched_autogroup_exit(struct signal_struct *sig);
2120 #ifdef CONFIG_PROC_FS
2121 extern void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m);
2122 extern int proc_sched_autogroup_set_nice(struct task_struct *p, int nice);
2123 #endif
2124 #else
2125 static inline void sched_autogroup_create_attach(struct task_struct *p) { }
2126 static inline void sched_autogroup_detach(struct task_struct *p) { }
2127 static inline void sched_autogroup_fork(struct signal_struct *sig) { }
2128 static inline void sched_autogroup_exit(struct signal_struct *sig) { }
2129 #endif
2130 
2131 extern bool yield_to(struct task_struct *p, bool preempt);
2132 extern void set_user_nice(struct task_struct *p, long nice);
2133 extern int task_prio(const struct task_struct *p);
2134 /**
2135  * task_nice - return the nice value of a given task.
2136  * @p: the task in question.
2137  *
2138  * Return: The nice value [ -20 ... 0 ... 19 ].
2139  */
2140 static inline int task_nice(const struct task_struct *p)
2141 {
2142         return PRIO_TO_NICE((p)->static_prio);
2143 }
2144 extern int can_nice(const struct task_struct *p, const int nice);
2145 extern int task_curr(const struct task_struct *p);
2146 extern int idle_cpu(int cpu);
2147 extern int sched_setscheduler(struct task_struct *, int,
2148                               const struct sched_param *);
2149 extern int sched_setscheduler_nocheck(struct task_struct *, int,
2150                                       const struct sched_param *);
2151 extern int sched_setattr(struct task_struct *,
2152                          const struct sched_attr *);
2153 extern struct task_struct *idle_task(int cpu);
2154 /**
2155  * is_idle_task - is the specified task an idle task?
2156  * @p: the task in question.
2157  *
2158  * Return: 1 if @p is an idle task. 0 otherwise.
2159  */
2160 static inline bool is_idle_task(const struct task_struct *p)
2161 {
2162         return p->pid == 0;
2163 }
2164 extern struct task_struct *curr_task(int cpu);
2165 extern void set_curr_task(int cpu, struct task_struct *p);
2166 
2167 void yield(void);
2168 
2169 /*
2170  * The default (Linux) execution domain.
2171  */
2172 extern struct exec_domain       default_exec_domain;
2173 
2174 union thread_union {
2175         struct thread_info thread_info;
2176         unsigned long stack[THREAD_SIZE/sizeof(long)];
2177 };
2178 
2179 #ifndef __HAVE_ARCH_KSTACK_END
2180 static inline int kstack_end(void *addr)
2181 {
2182         /* Reliable end of stack detection:
2183          * Some APM bios versions misalign the stack
2184          */
2185         return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*)));
2186 }
2187 #endif
2188 
2189 extern union thread_union init_thread_union;
2190 extern struct task_struct init_task;
2191 
2192 extern struct   mm_struct init_mm;
2193 
2194 extern struct pid_namespace init_pid_ns;
2195 
2196 /*
2197  * find a task by one of its numerical ids
2198  *
2199  * find_task_by_pid_ns():
2200  *      finds a task by its pid in the specified namespace
2201  * find_task_by_vpid():
2202  *      finds a task by its virtual pid
2203  *
2204  * see also find_vpid() etc in include/linux/pid.h
2205  */
2206 
2207 extern struct task_struct *find_task_by_vpid(pid_t nr);
2208 extern struct task_struct *find_task_by_pid_ns(pid_t nr,
2209                 struct pid_namespace *ns);
2210 
2211 /* per-UID process charging. */
2212 extern struct user_struct * alloc_uid(kuid_t);
2213 static inline struct user_struct *get_uid(struct user_struct *u)
2214 {
2215         atomic_inc(&u->__count);
2216         return u;
2217 }
2218 extern void free_uid(struct user_struct *);
2219 
2220 #include <asm/current.h>
2221 
2222 extern void xtime_update(unsigned long ticks);
2223 
2224 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
2225 extern int wake_up_process(struct task_struct *tsk);
2226 extern void wake_up_new_task(struct task_struct *tsk);
2227 #ifdef CONFIG_SMP
2228  extern void kick_process(struct task_struct *tsk);
2229 #else
2230  static inline void kick_process(struct task_struct *tsk) { }
2231 #endif
2232 extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
2233 extern void sched_dead(struct task_struct *p);
2234 
2235 extern void proc_caches_init(void);
2236 extern void flush_signals(struct task_struct *);
2237 extern void __flush_signals(struct task_struct *);
2238 extern void ignore_signals(struct task_struct *);
2239 extern void flush_signal_handlers(struct task_struct *, int force_default);
2240 extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
2241 
2242 static inline int dequeue_signal_lock(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
2243 {
2244         unsigned long flags;
2245         int ret;
2246 
2247         spin_lock_irqsave(&tsk->sighand->siglock, flags);
2248         ret = dequeue_signal(tsk, mask, info);
2249         spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2250 
2251         return ret;
2252 }
2253 
2254 extern void block_all_signals(int (*notifier)(void *priv), void *priv,
2255                               sigset_t *mask);
2256 extern void unblock_all_signals(void);
2257 extern void release_task(struct task_struct * p);
2258 extern int send_sig_info(int, struct siginfo *, struct task_struct *);
2259 extern int force_sigsegv(int, struct task_struct *);
2260 extern int force_sig_info(int, struct siginfo *, struct task_struct *);
2261 extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
2262 extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
2263 extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *,
2264                                 const struct cred *, u32);
2265 extern int kill_pgrp(struct pid *pid, int sig, int priv);
2266 extern int kill_pid(struct pid *pid, int sig, int priv);
2267 extern int kill_proc_info(int, struct siginfo *, pid_t);
2268 extern __must_check bool do_notify_parent(struct task_struct *, int);
2269 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
2270 extern void force_sig(int, struct task_struct *);
2271 extern int send_sig(int, struct task_struct *, int);
2272 extern int zap_other_threads(struct task_struct *p);
2273 extern struct sigqueue *sigqueue_alloc(void);
2274 extern void sigqueue_free(struct sigqueue *);
2275 extern int send_sigqueue(struct sigqueue *,  struct task_struct *, int group);
2276 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
2277 
2278 static inline void restore_saved_sigmask(void)
2279 {
2280         if (test_and_clear_restore_sigmask())
2281                 __set_current_blocked(&current->saved_sigmask);
2282 }
2283 
2284 static inline sigset_t *sigmask_to_save(void)
2285 {
2286         sigset_t *res = &current->blocked;
2287         if (unlikely(test_restore_sigmask()))
2288                 res = &current->saved_sigmask;
2289         return res;
2290 }
2291 
2292 static inline int kill_cad_pid(int sig, int priv)
2293 {
2294         return kill_pid(cad_pid, sig, priv);
2295 }
2296 
2297 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
2298 #define SEND_SIG_NOINFO ((struct siginfo *) 0)
2299 #define SEND_SIG_PRIV   ((struct siginfo *) 1)
2300 #define SEND_SIG_FORCED ((struct siginfo *) 2)
2301 
2302 /*
2303  * True if we are on the alternate signal stack.
2304  */
2305 static inline int on_sig_stack(unsigned long sp)
2306 {
2307 #ifdef CONFIG_STACK_GROWSUP
2308         return sp >= current->sas_ss_sp &&
2309                 sp - current->sas_ss_sp < current->sas_ss_size;
2310 #else
2311         return sp > current->sas_ss_sp &&
2312                 sp - current->sas_ss_sp <= current->sas_ss_size;
2313 #endif
2314 }
2315 
2316 static inline int sas_ss_flags(unsigned long sp)
2317 {
2318         return (current->sas_ss_size == 0 ? SS_DISABLE
2319                 : on_sig_stack(sp) ? SS_ONSTACK : 0);
2320 }
2321 
2322 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
2323 {
2324         if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
2325 #ifdef CONFIG_STACK_GROWSUP
2326                 return current->sas_ss_sp;
2327 #else
2328                 return current->sas_ss_sp + current->sas_ss_size;
2329 #endif
2330         return sp;
2331 }
2332 
2333 /*
2334  * Routines for handling mm_structs
2335  */
2336 extern struct mm_struct * mm_alloc(void);
2337 
2338 /* mmdrop drops the mm and the page tables */
2339 extern void __mmdrop(struct mm_struct *);
2340 static inline void mmdrop(struct mm_struct * mm)
2341 {
2342         if (unlikely(atomic_dec_and_test(&mm->mm_count)))
2343                 __mmdrop(mm);
2344 }
2345 
2346 /* mmput gets rid of the mappings and all user-space */
2347 extern void mmput(struct mm_struct *);
2348 /* Grab a reference to a task's mm, if it is not already going away */
2349 extern struct mm_struct *get_task_mm(struct task_struct *task);
2350 /*
2351  * Grab a reference to a task's mm, if it is not already going away
2352  * and ptrace_may_access with the mode parameter passed to it
2353  * succeeds.
2354  */
2355 extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode);
2356 /* Remove the current tasks stale references to the old mm_struct */
2357 extern void mm_release(struct task_struct *, struct mm_struct *);
2358 
2359 extern int copy_thread(unsigned long, unsigned long, unsigned long,
2360                         struct task_struct *);
2361 extern void flush_thread(void);
2362 extern void exit_thread(void);
2363 
2364 extern void exit_files(struct task_struct *);
2365 extern void __cleanup_sighand(struct sighand_struct *);
2366 
2367 extern void exit_itimers(struct signal_struct *);
2368 extern void flush_itimer_signals(void);
2369 
2370 extern void do_group_exit(int);
2371 
2372 extern int allow_signal(int);
2373 extern int disallow_signal(int);
2374 
2375 extern int do_execve(struct filename *,
2376                      const char __user * const __user *,
2377                      const char __user * const __user *);
2378 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
2379 struct task_struct *fork_idle(int);
2380 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
2381 
2382 extern void set_task_comm(struct task_struct *tsk, const char *from);
2383 extern char *get_task_comm(char *to, struct task_struct *tsk);
2384 
2385 #ifdef CONFIG_SMP
2386 void scheduler_ipi(void);
2387 extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
2388 #else
2389 static inline void scheduler_ipi(void) { }
2390 static inline unsigned long wait_task_inactive(struct task_struct *p,
2391                                                long match_state)
2392 {
2393         return 1;
2394 }
2395 #endif
2396 
2397 #define next_task(p) \
2398         list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
2399 
2400 #define for_each_process(p) \
2401         for (p = &init_task ; (p = next_task(p)) != &init_task ; )
2402 
2403 extern bool current_is_single_threaded(void);
2404 
2405 /*
2406  * Careful: do_each_thread/while_each_thread is a double loop so
2407  *          'break' will not work as expected - use goto instead.
2408  */
2409 #define do_each_thread(g, t) \
2410         for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
2411 
2412 #define while_each_thread(g, t) \
2413         while ((t = next_thread(t)) != g)
2414 
2415 #define __for_each_thread(signal, t)    \
2416         list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
2417 
2418 #define for_each_thread(p, t)           \
2419         __for_each_thread((p)->signal, t)
2420 
2421 /* Careful: this is a double loop, 'break' won't work as expected. */
2422 #define for_each_process_thread(p, t)   \
2423         for_each_process(p) for_each_thread(p, t)
2424 
2425 static inline int get_nr_threads(struct task_struct *tsk)
2426 {
2427         return tsk->signal->nr_threads;
2428 }
2429 
2430 static inline bool thread_group_leader(struct task_struct *p)
2431 {
2432         return p->exit_signal >= 0;
2433 }
2434 
2435 /* Do to the insanities of de_thread it is possible for a process
2436  * to have the pid of the thread group leader without actually being
2437  * the thread group leader.  For iteration through the pids in proc
2438  * all we care about is that we have a task with the appropriate
2439  * pid, we don't actually care if we have the right task.
2440  */
2441 static inline bool has_group_leader_pid(struct task_struct *p)
2442 {
2443         return task_pid(p) == p->signal->leader_pid;
2444 }
2445 
2446 static inline
2447 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
2448 {
2449         return p1->signal == p2->signal;
2450 }
2451 
2452 static inline struct task_struct *next_thread(const struct task_struct *p)
2453 {
2454         return list_entry_rcu(p->thread_group.next,
2455                               struct task_struct, thread_group);
2456 }
2457 
2458 static inline int thread_group_empty(struct task_struct *p)
2459 {
2460         return list_empty(&p->thread_group);
2461 }
2462 
2463 #define delay_group_leader(p) \
2464                 (thread_group_leader(p) && !thread_group_empty(p))
2465 
2466 /*
2467  * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
2468  * subscriptions and synchronises with wait4().  Also used in procfs.  Also
2469  * pins the final release of task.io_context.  Also protects ->cpuset and
2470  * ->cgroup.subsys[]. And ->vfork_done.
2471  *
2472  * Nests both inside and outside of read_lock(&tasklist_lock).
2473  * It must not be nested with write_lock_irq(&tasklist_lock),
2474  * neither inside nor outside.
2475  */
2476 static inline void task_lock(struct task_struct *p)
2477 {
2478         spin_lock(&p->alloc_lock);
2479 }
2480 
2481 static inline void task_unlock(struct task_struct *p)
2482 {
2483         spin_unlock(&p->alloc_lock);
2484 }
2485 
2486 extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
2487                                                         unsigned long *flags);
2488 
2489 static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
2490                                                        unsigned long *flags)
2491 {
2492         struct sighand_struct *ret;
2493 
2494         ret = __lock_task_sighand(tsk, flags);
2495         (void)__cond_lock(&tsk->sighand->siglock, ret);
2496         return ret;
2497 }
2498 
2499 static inline void unlock_task_sighand(struct task_struct *tsk,
2500                                                 unsigned long *flags)
2501 {
2502         spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
2503 }
2504 
2505 #ifdef CONFIG_CGROUPS
2506 static inline void threadgroup_change_begin(struct task_struct *tsk)
2507 {
2508         down_read(&tsk->signal->group_rwsem);
2509 }
2510 static inline void threadgroup_change_end(struct task_struct *tsk)
2511 {
2512         up_read(&tsk->signal->group_rwsem);
2513 }
2514 
2515 /**
2516  * threadgroup_lock - lock threadgroup
2517  * @tsk: member task of the threadgroup to lock
2518  *
2519  * Lock the threadgroup @tsk belongs to.  No new task is allowed to enter
2520  * and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
2521  * change ->group_leader/pid.  This is useful for cases where the threadgroup
2522  * needs to stay stable across blockable operations.
2523  *
2524  * fork and exit paths explicitly call threadgroup_change_{begin|end}() for
2525  * synchronization.  While held, no new task will be added to threadgroup
2526  * and no existing live task will have its PF_EXITING set.
2527  *
2528  * de_thread() does threadgroup_change_{begin|end}() when a non-leader
2529  * sub-thread becomes a new leader.
2530  */
2531 static inline void threadgroup_lock(struct task_struct *tsk)
2532 {
2533         down_write(&tsk->signal->group_rwsem);
2534 }
2535 
2536 /**
2537  * threadgroup_unlock - unlock threadgroup
2538  * @tsk: member task of the threadgroup to unlock
2539  *
2540  * Reverse threadgroup_lock().
2541  */
2542 static inline void threadgroup_unlock(struct task_struct *tsk)
2543 {
2544         up_write(&tsk->signal->group_rwsem);
2545 }
2546 #else
2547 static inline void threadgroup_change_begin(struct task_struct *tsk) {}
2548 static inline void threadgroup_change_end(struct task_struct *tsk) {}
2549 static inline void threadgroup_lock(struct task_struct *tsk) {}
2550 static inline void threadgroup_unlock(struct task_struct *tsk) {}
2551 #endif
2552 
2553 #ifndef __HAVE_THREAD_FUNCTIONS
2554 
2555 #define task_thread_info(task)  ((struct thread_info *)(task)->stack)
2556 #define task_stack_page(task)   ((task)->stack)
2557 
2558 static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)
2559 {
2560         *task_thread_info(p) = *task_thread_info(org);
2561         task_thread_info(p)->task = p;
2562 }
2563 
2564 static inline unsigned long *end_of_stack(struct task_struct *p)
2565 {
2566         return (unsigned long *)(task_thread_info(p) + 1);
2567 }
2568 
2569 #endif
2570 
2571 static inline int object_is_on_stack(void *obj)
2572 {
2573         void *stack = task_stack_page(current);
2574 
2575         return (obj >= stack) && (obj < (stack + THREAD_SIZE));
2576 }
2577 
2578 extern void thread_info_cache_init(void);
2579 
2580 #ifdef CONFIG_DEBUG_STACK_USAGE
2581 static inline unsigned long stack_not_used(struct task_struct *p)
2582 {
2583         unsigned long *n = end_of_stack(p);
2584 
2585         do {    /* Skip over canary */
2586                 n++;
2587         } while (!*n);
2588 
2589         return (unsigned long)n - (unsigned long)end_of_stack(p);
2590 }
2591 #endif
2592 
2593 /* set thread flags in other task's structures
2594  * - see asm/thread_info.h for TIF_xxxx flags available
2595  */
2596 static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
2597 {
2598         set_ti_thread_flag(task_thread_info(tsk), flag);
2599 }
2600 
2601 static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2602 {
2603         clear_ti_thread_flag(task_thread_info(tsk), flag);
2604 }
2605 
2606 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
2607 {
2608         return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
2609 }
2610 
2611 static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2612 {
2613         return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
2614 }
2615 
2616 static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
2617 {
2618         return test_ti_thread_flag(task_thread_info(tsk), flag);
2619 }
2620 
2621 static inline void set_tsk_need_resched(struct task_struct *tsk)
2622 {
2623         set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2624 }
2625 
2626 static inline void clear_tsk_need_resched(struct task_struct *tsk)
2627 {
2628         clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2629 }
2630 
2631 static inline int test_tsk_need_resched(struct task_struct *tsk)
2632 {
2633         return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
2634 }
2635 
2636 static inline int restart_syscall(void)
2637 {
2638         set_tsk_thread_flag(current, TIF_SIGPENDING);
2639         return -ERESTARTNOINTR;
2640 }
2641 
2642 static inline int signal_pending(struct task_struct *p)
2643 {
2644         return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
2645 }
2646 
2647 static inline int __fatal_signal_pending(struct task_struct *p)
2648 {
2649         return unlikely(sigismember(&p->pending.signal, SIGKILL));
2650 }
2651 
2652 static inline int fatal_signal_pending(struct task_struct *p)
2653 {
2654         return signal_pending(p) && __fatal_signal_pending(p);
2655 }
2656 
2657 static inline int signal_pending_state(long state, struct task_struct *p)
2658 {
2659         if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
2660                 return 0;
2661         if (!signal_pending(p))
2662                 return 0;
2663 
2664         return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
2665 }
2666 
2667 /*
2668  * cond_resched() and cond_resched_lock(): latency reduction via
2669  * explicit rescheduling in places that are safe. The return
2670  * value indicates whether a reschedule was done in fact.
2671  * cond_resched_lock() will drop the spinlock before scheduling,
2672  * cond_resched_softirq() will enable bhs before scheduling.
2673  */
2674 extern int _cond_resched(void);
2675 
2676 #define cond_resched() ({                       \
2677         __might_sleep(__FILE__, __LINE__, 0);   \
2678         _cond_resched();                        \
2679 })
2680 
2681 extern int __cond_resched_lock(spinlock_t *lock);
2682 
2683 #ifdef CONFIG_PREEMPT_COUNT
2684 #define PREEMPT_LOCK_OFFSET     PREEMPT_OFFSET
2685 #else
2686 #define PREEMPT_LOCK_OFFSET     0
2687 #endif
2688 
2689 #define cond_resched_lock(lock) ({                              \
2690         __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \
2691         __cond_resched_lock(lock);                              \
2692 })
2693 
2694 extern int __cond_resched_softirq(void);
2695 
2696 #define cond_resched_softirq() ({                                       \
2697         __might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET);      \
2698         __cond_resched_softirq();                                       \
2699 })
2700 
2701 static inline void cond_resched_rcu(void)
2702 {
2703 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
2704         rcu_read_unlock();
2705         cond_resched();
2706         rcu_read_lock();
2707 #endif
2708 }
2709 
2710 /*
2711  * Does a critical section need to be broken due to another
2712  * task waiting?: (technically does not depend on CONFIG_PREEMPT,
2713  * but a general need for low latency)
2714  */
2715 static inline int spin_needbreak(spinlock_t *lock)
2716 {
2717 #ifdef CONFIG_PREEMPT
2718         return spin_is_contended(lock);
2719 #else
2720         return 0;
2721 #endif
2722 }
2723 
2724 /*
2725  * Idle thread specific functions to determine the need_resched
2726  * polling state. We have two versions, one based on TS_POLLING in
2727  * thread_info.status and one based on TIF_POLLING_NRFLAG in
2728  * thread_info.flags
2729  */
2730 #ifdef TS_POLLING
2731 static inline int tsk_is_polling(struct task_struct *p)
2732 {
2733         return task_thread_info(p)->status & TS_POLLING;
2734 }
2735 static inline void __current_set_polling(void)
2736 {
2737         current_thread_info()->status |= TS_POLLING;
2738 }
2739 
2740 static inline bool __must_check current_set_polling_and_test(void)
2741 {
2742         __current_set_polling();
2743 
2744         /*
2745          * Polling state must be visible before we test NEED_RESCHED,
2746          * paired by resched_task()
2747          */
2748         smp_mb();
2749 
2750         return unlikely(tif_need_resched());
2751 }
2752 
2753 static inline void __current_clr_polling(void)
2754 {
2755         current_thread_info()->status &= ~TS_POLLING;
2756 }
2757 
2758 static inline bool __must_check current_clr_polling_and_test(void)
2759 {
2760         __current_clr_polling();
2761 
2762         /*
2763          * Polling state must be visible before we test NEED_RESCHED,
2764          * paired by resched_task()
2765          */
2766         smp_mb();
2767 
2768         return unlikely(tif_need_resched());
2769 }
2770 #elif defined(TIF_POLLING_NRFLAG)
2771 static inline int tsk_is_polling(struct task_struct *p)
2772 {
2773         return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
2774 }
2775 
2776 static inline void __current_set_polling(void)
2777 {
2778         set_thread_flag(TIF_POLLING_NRFLAG);
2779 }
2780 
2781 static inline bool __must_check current_set_polling_and_test(void)
2782 {
2783         __current_set_polling();
2784 
2785         /*
2786          * Polling state must be visible before we test NEED_RESCHED,
2787          * paired by resched_task()
2788          *
2789          * XXX: assumes set/clear bit are identical barrier wise.
2790          */
2791         smp_mb__after_clear_bit();
2792 
2793         return unlikely(tif_need_resched());
2794 }
2795 
2796 static inline void __current_clr_polling(void)
2797 {
2798         clear_thread_flag(TIF_POLLING_NRFLAG);
2799 }
2800 
2801 static inline bool __must_check current_clr_polling_and_test(void)
2802 {
2803         __current_clr_polling();
2804 
2805         /*
2806          * Polling state must be visible before we test NEED_RESCHED,
2807          * paired by resched_task()
2808          */
2809         smp_mb__after_clear_bit();
2810 
2811         return unlikely(tif_need_resched());
2812 }
2813 
2814 #else
2815 static inline int tsk_is_polling(struct task_struct *p) { return 0; }
2816 static inline void __current_set_polling(void) { }
2817 static inline void __current_clr_polling(void) { }
2818 
2819 static inline bool __must_check current_set_polling_and_test(void)
2820 {
2821         return unlikely(tif_need_resched());
2822 }
2823 static inline bool __must_check current_clr_polling_and_test(void)
2824 {
2825         return unlikely(tif_need_resched());
2826 }
2827 #endif
2828 
2829 static inline void current_clr_polling(void)
2830 {
2831         __current_clr_polling();
2832 
2833         /*
2834          * Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
2835          * Once the bit is cleared, we'll get IPIs with every new
2836          * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
2837          * fold.
2838          */
2839         smp_mb(); /* paired with resched_task() */
2840 
2841         preempt_fold_need_resched();
2842 }
2843 
2844 static __always_inline bool need_resched(void)
2845 {
2846         return unlikely(tif_need_resched());
2847 }
2848 
2849 /*
2850  * Thread group CPU time accounting.
2851  */
2852 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
2853 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);
2854 
2855 static inline void thread_group_cputime_init(struct signal_struct *sig)
2856 {
2857         raw_spin_lock_init(&sig->cputimer.lock);
2858 }
2859 
2860 /*
2861  * Reevaluate whether the task has signals pending delivery.
2862  * Wake the task if so.
2863  * This is required every time the blocked sigset_t changes.
2864  * callers must hold sighand->siglock.
2865  */
2866 extern void recalc_sigpending_and_wake(struct task_struct *t);
2867 extern void recalc_sigpending(void);
2868 
2869 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
2870 
2871 static inline void signal_wake_up(struct task_struct *t, bool resume)
2872 {
2873         signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
2874 }
2875 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
2876 {
2877         signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
2878 }
2879 
2880 /*
2881  * Wrappers for p->thread_info->cpu access. No-op on UP.
2882  */
2883 #ifdef CONFIG_SMP
2884 
2885 static inline unsigned int task_cpu(const struct task_struct *p)
2886 {
2887         return task_thread_info(p)->cpu;
2888 }
2889 
2890 static inline int task_node(const struct task_struct *p)
2891 {
2892         return cpu_to_node(task_cpu(p));
2893 }
2894 
2895 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
2896 
2897 #else
2898 
2899 static inline unsigned int task_cpu(const struct task_struct *p)
2900 {
2901         return 0;
2902 }
2903 
2904 static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
2905 {
2906 }
2907 
2908 #endif /* CONFIG_SMP */
2909 
2910 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
2911 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
2912 
2913 #ifdef CONFIG_CGROUP_SCHED
2914 extern struct task_group root_task_group;
2915 #endif /* CONFIG_CGROUP_SCHED */
2916 
2917 extern int task_can_switch_user(struct user_struct *up,
2918                                         struct task_struct *tsk);
2919 
2920 #ifdef CONFIG_TASK_XACCT
2921 static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
2922 {
2923         tsk->ioac.rchar += amt;
2924 }
2925 
2926 static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
2927 {
2928         tsk->ioac.wchar += amt;
2929 }
2930 
2931 static inline void inc_syscr(struct task_struct *tsk)
2932 {
2933         tsk->ioac.syscr++;
2934 }
2935 
2936 static inline void inc_syscw(struct task_struct *tsk)
2937 {
2938         tsk->ioac.syscw++;
2939 }
2940 #else
2941 static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
2942 {
2943 }
2944 
2945 static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
2946 {
2947 }
2948 
2949 static inline void inc_syscr(struct task_struct *tsk)
2950 {
2951 }
2952 
2953 static inline void inc_syscw(struct task_struct *tsk)
2954 {
2955 }
2956 #endif
2957 
2958 #ifndef TASK_SIZE_OF
2959 #define TASK_SIZE_OF(tsk)       TASK_SIZE
2960 #endif
2961 
2962 #ifdef CONFIG_MM_OWNER
2963 extern void mm_update_next_owner(struct mm_struct *mm);
2964 extern void mm_init_owner(struct mm_struct *mm, struct task_struct *p);
2965 #else
2966 static inline void mm_update_next_owner(struct mm_struct *mm)
2967 {
2968 }
2969 
2970 static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
2971 {
2972 }
2973 #endif /* CONFIG_MM_OWNER */
2974 
2975 static inline unsigned long task_rlimit(const struct task_struct *tsk,
2976                 unsigned int limit)
2977 {
2978         return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_cur);
2979 }
2980 
2981 static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
2982                 unsigned int limit)
2983 {
2984         return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_max);
2985 }
2986 
2987 static inline unsigned long rlimit(unsigned int limit)
2988 {
2989         return task_rlimit(current, limit);
2990 }
2991 
2992 static inline unsigned long rlimit_max(unsigned int limit)
2993 {
2994         return task_rlimit_max(current, limit);
2995 }
2996 
2997 #endif
2998 

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