linux/include/linux/sched.h
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   1#ifndef _LINUX_SCHED_H
   2#define _LINUX_SCHED_H
   3
   4/*
   5 * cloning flags:
   6 */
   7#define CSIGNAL         0x000000ff      /* signal mask to be sent at exit */
   8#define CLONE_VM        0x00000100      /* set if VM shared between processes */
   9#define CLONE_FS        0x00000200      /* set if fs info shared between processes */
  10#define CLONE_FILES     0x00000400      /* set if open files shared between processes */
  11#define CLONE_SIGHAND   0x00000800      /* set if signal handlers and blocked signals shared */
  12#define CLONE_PTRACE    0x00002000      /* set if we want to let tracing continue on the child too */
  13#define CLONE_VFORK     0x00004000      /* set if the parent wants the child to wake it up on mm_release */
  14#define CLONE_PARENT    0x00008000      /* set if we want to have the same parent as the cloner */
  15#define CLONE_THREAD    0x00010000      /* Same thread group? */
  16#define CLONE_NEWNS     0x00020000      /* New namespace group? */
  17#define CLONE_SYSVSEM   0x00040000      /* share system V SEM_UNDO semantics */
  18#define CLONE_SETTLS    0x00080000      /* create a new TLS for the child */
  19#define CLONE_PARENT_SETTID     0x00100000      /* set the TID in the parent */
  20#define CLONE_CHILD_CLEARTID    0x00200000      /* clear the TID in the child */
  21#define CLONE_DETACHED          0x00400000      /* Unused, ignored */
  22#define CLONE_UNTRACED          0x00800000      /* set if the tracing process can't force CLONE_PTRACE on this clone */
  23#define CLONE_CHILD_SETTID      0x01000000      /* set the TID in the child */
  24/* 0x02000000 was previously the unused CLONE_STOPPED (Start in stopped state)
  25   and is now available for re-use. */
  26#define CLONE_NEWUTS            0x04000000      /* New utsname group? */
  27#define CLONE_NEWIPC            0x08000000      /* New ipcs */
  28#define CLONE_NEWUSER           0x10000000      /* New user namespace */
  29#define CLONE_NEWPID            0x20000000      /* New pid namespace */
  30#define CLONE_NEWNET            0x40000000      /* New network namespace */
  31#define CLONE_IO                0x80000000      /* Clone io context */
  32
  33/*
  34 * Scheduling policies
  35 */
  36#define SCHED_NORMAL            0
  37#define SCHED_FIFO              1
  38#define SCHED_RR                2
  39#define SCHED_BATCH             3
  40/* SCHED_ISO: reserved but not implemented yet */
  41#define SCHED_IDLE              5
  42/* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */
  43#define SCHED_RESET_ON_FORK     0x40000000
  44
  45#ifdef __KERNEL__
  46
  47struct sched_param {
  48        int sched_priority;
  49};
  50
  51#include <asm/param.h>  /* for HZ */
  52
  53#include <linux/capability.h>
  54#include <linux/threads.h>
  55#include <linux/kernel.h>
  56#include <linux/types.h>
  57#include <linux/timex.h>
  58#include <linux/jiffies.h>
  59#include <linux/rbtree.h>
  60#include <linux/thread_info.h>
  61#include <linux/cpumask.h>
  62#include <linux/errno.h>
  63#include <linux/nodemask.h>
  64#include <linux/mm_types.h>
  65
  66#include <asm/page.h>
  67#include <asm/ptrace.h>
  68#include <asm/cputime.h>
  69
  70#include <linux/smp.h>
  71#include <linux/sem.h>
  72#include <linux/signal.h>
  73#include <linux/compiler.h>
  74#include <linux/completion.h>
  75#include <linux/pid.h>
  76#include <linux/percpu.h>
  77#include <linux/topology.h>
  78#include <linux/proportions.h>
  79#include <linux/seccomp.h>
  80#include <linux/rcupdate.h>
  81#include <linux/rculist.h>
  82#include <linux/rtmutex.h>
  83
  84#include <linux/time.h>
  85#include <linux/param.h>
  86#include <linux/resource.h>
  87#include <linux/timer.h>
  88#include <linux/hrtimer.h>
  89#include <linux/task_io_accounting.h>
  90#include <linux/latencytop.h>
  91#include <linux/cred.h>
  92#include <linux/llist.h>
  93
  94#include <asm/processor.h>
  95
  96struct exec_domain;
  97struct futex_pi_state;
  98struct robust_list_head;
  99struct bio_list;
 100struct fs_struct;
 101struct perf_event_context;
 102struct blk_plug;
 103
 104/*
 105 * List of flags we want to share for kernel threads,
 106 * if only because they are not used by them anyway.
 107 */
 108#define CLONE_KERNEL    (CLONE_FS | CLONE_FILES | CLONE_SIGHAND)
 109
 110/*
 111 * These are the constant used to fake the fixed-point load-average
 112 * counting. Some notes:
 113 *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
 114 *    a load-average precision of 10 bits integer + 11 bits fractional
 115 *  - if you want to count load-averages more often, you need more
 116 *    precision, or rounding will get you. With 2-second counting freq,
 117 *    the EXP_n values would be 1981, 2034 and 2043 if still using only
 118 *    11 bit fractions.
 119 */
 120extern unsigned long avenrun[];         /* Load averages */
 121extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
 122
 123#define FSHIFT          11              /* nr of bits of precision */
 124#define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
 125#define LOAD_FREQ       (5*HZ+1)        /* 5 sec intervals */
 126#define EXP_1           1884            /* 1/exp(5sec/1min) as fixed-point */
 127#define EXP_5           2014            /* 1/exp(5sec/5min) */
 128#define EXP_15          2037            /* 1/exp(5sec/15min) */
 129
 130#define CALC_LOAD(load,exp,n) \
 131        load *= exp; \
 132        load += n*(FIXED_1-exp); \
 133        load >>= FSHIFT;
 134
 135extern unsigned long total_forks;
 136extern int nr_threads;
 137DECLARE_PER_CPU(unsigned long, process_counts);
 138extern int nr_processes(void);
 139extern unsigned long nr_running(void);
 140extern unsigned long nr_uninterruptible(void);
 141extern unsigned long nr_iowait(void);
 142extern unsigned long nr_iowait_cpu(int cpu);
 143extern unsigned long this_cpu_load(void);
 144
 145
 146extern void calc_global_load(unsigned long ticks);
 147
 148extern unsigned long get_parent_ip(unsigned long addr);
 149
 150struct seq_file;
 151struct cfs_rq;
 152struct task_group;
 153#ifdef CONFIG_SCHED_DEBUG
 154extern void proc_sched_show_task(struct task_struct *p, struct seq_file *m);
 155extern void proc_sched_set_task(struct task_struct *p);
 156extern void
 157print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
 158#else
 159static inline void
 160proc_sched_show_task(struct task_struct *p, struct seq_file *m)
 161{
 162}
 163static inline void proc_sched_set_task(struct task_struct *p)
 164{
 165}
 166static inline void
 167print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 168{
 169}
 170#endif
 171
 172/*
 173 * Task state bitmask. NOTE! These bits are also
 174 * encoded in fs/proc/array.c: get_task_state().
 175 *
 176 * We have two separate sets of flags: task->state
 177 * is about runnability, while task->exit_state are
 178 * about the task exiting. Confusing, but this way
 179 * modifying one set can't modify the other one by
 180 * mistake.
 181 */
 182#define TASK_RUNNING            0
 183#define TASK_INTERRUPTIBLE      1
 184#define TASK_UNINTERRUPTIBLE    2
 185#define __TASK_STOPPED          4
 186#define __TASK_TRACED           8
 187/* in tsk->exit_state */
 188#define EXIT_ZOMBIE             16
 189#define EXIT_DEAD               32
 190/* in tsk->state again */
 191#define TASK_DEAD               64
 192#define TASK_WAKEKILL           128
 193#define TASK_WAKING             256
 194#define TASK_STATE_MAX          512
 195
 196#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKW"
 197
 198extern char ___assert_task_state[1 - 2*!!(
 199                sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1)];
 200
 201/* Convenience macros for the sake of set_task_state */
 202#define TASK_KILLABLE           (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
 203#define TASK_STOPPED            (TASK_WAKEKILL | __TASK_STOPPED)
 204#define TASK_TRACED             (TASK_WAKEKILL | __TASK_TRACED)
 205
 206/* Convenience macros for the sake of wake_up */
 207#define TASK_NORMAL             (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
 208#define TASK_ALL                (TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)
 209
 210/* get_task_state() */
 211#define TASK_REPORT             (TASK_RUNNING | TASK_INTERRUPTIBLE | \
 212                                 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
 213                                 __TASK_TRACED)
 214
 215#define task_is_traced(task)    ((task->state & __TASK_TRACED) != 0)
 216#define task_is_stopped(task)   ((task->state & __TASK_STOPPED) != 0)
 217#define task_is_dead(task)      ((task)->exit_state != 0)
 218#define task_is_stopped_or_traced(task) \
 219                        ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
 220#define task_contributes_to_load(task)  \
 221                                ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
 222                                 (task->flags & PF_FROZEN) == 0)
 223
 224#define __set_task_state(tsk, state_value)              \
 225        do { (tsk)->state = (state_value); } while (0)
 226#define set_task_state(tsk, state_value)                \
 227        set_mb((tsk)->state, (state_value))
 228
 229/*
 230 * set_current_state() includes a barrier so that the write of current->state
 231 * is correctly serialised wrt the caller's subsequent test of whether to
 232 * actually sleep:
 233 *
 234 *      set_current_state(TASK_UNINTERRUPTIBLE);
 235 *      if (do_i_need_to_sleep())
 236 *              schedule();
 237 *
 238 * If the caller does not need such serialisation then use __set_current_state()
 239 */
 240#define __set_current_state(state_value)                        \
 241        do { current->state = (state_value); } while (0)
 242#define set_current_state(state_value)          \
 243        set_mb(current->state, (state_value))
 244
 245/* Task command name length */
 246#define TASK_COMM_LEN 16
 247
 248#include <linux/spinlock.h>
 249
 250/*
 251 * This serializes "schedule()" and also protects
 252 * the run-queue from deletions/modifications (but
 253 * _adding_ to the beginning of the run-queue has
 254 * a separate lock).
 255 */
 256extern rwlock_t tasklist_lock;
 257extern spinlock_t mmlist_lock;
 258
 259struct task_struct;
 260
 261#ifdef CONFIG_PROVE_RCU
 262extern int lockdep_tasklist_lock_is_held(void);
 263#endif /* #ifdef CONFIG_PROVE_RCU */
 264
 265extern void sched_init(void);
 266extern void sched_init_smp(void);
 267extern asmlinkage void schedule_tail(struct task_struct *prev);
 268extern void init_idle(struct task_struct *idle, int cpu);
 269extern void init_idle_bootup_task(struct task_struct *idle);
 270
 271extern int runqueue_is_locked(int cpu);
 272
 273#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
 274extern void select_nohz_load_balancer(int stop_tick);
 275extern void set_cpu_sd_state_idle(void);
 276extern int get_nohz_timer_target(void);
 277#else
 278static inline void select_nohz_load_balancer(int stop_tick) { }
 279static inline void set_cpu_sd_state_idle(void) { }
 280#endif
 281
 282/*
 283 * Only dump TASK_* tasks. (0 for all tasks)
 284 */
 285extern void show_state_filter(unsigned long state_filter);
 286
 287static inline void show_state(void)
 288{
 289        show_state_filter(0);
 290}
 291
 292extern void show_regs(struct pt_regs *);
 293
 294/*
 295 * TASK is a pointer to the task whose backtrace we want to see (or NULL for current
 296 * task), SP is the stack pointer of the first frame that should be shown in the back
 297 * trace (or NULL if the entire call-chain of the task should be shown).
 298 */
 299extern void show_stack(struct task_struct *task, unsigned long *sp);
 300
 301void io_schedule(void);
 302long io_schedule_timeout(long timeout);
 303
 304extern void cpu_init (void);
 305extern void trap_init(void);
 306extern void update_process_times(int user);
 307extern void scheduler_tick(void);
 308
 309extern void sched_show_task(struct task_struct *p);
 310
 311#ifdef CONFIG_LOCKUP_DETECTOR
 312extern void touch_softlockup_watchdog(void);
 313extern void touch_softlockup_watchdog_sync(void);
 314extern void touch_all_softlockup_watchdogs(void);
 315extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
 316                                  void __user *buffer,
 317                                  size_t *lenp, loff_t *ppos);
 318extern unsigned int  softlockup_panic;
 319void lockup_detector_init(void);
 320#else
 321static inline void touch_softlockup_watchdog(void)
 322{
 323}
 324static inline void touch_softlockup_watchdog_sync(void)
 325{
 326}
 327static inline void touch_all_softlockup_watchdogs(void)
 328{
 329}
 330static inline void lockup_detector_init(void)
 331{
 332}
 333#endif
 334
 335#ifdef CONFIG_DETECT_HUNG_TASK
 336extern unsigned int  sysctl_hung_task_panic;
 337extern unsigned long sysctl_hung_task_check_count;
 338extern unsigned long sysctl_hung_task_timeout_secs;
 339extern unsigned long sysctl_hung_task_warnings;
 340extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
 341                                         void __user *buffer,
 342                                         size_t *lenp, loff_t *ppos);
 343#else
 344/* Avoid need for ifdefs elsewhere in the code */
 345enum { sysctl_hung_task_timeout_secs = 0 };
 346#endif
 347
 348/* Attach to any functions which should be ignored in wchan output. */
 349#define __sched         __attribute__((__section__(".sched.text")))
 350
 351/* Linker adds these: start and end of __sched functions */
 352extern char __sched_text_start[], __sched_text_end[];
 353
 354/* Is this address in the __sched functions? */
 355extern int in_sched_functions(unsigned long addr);
 356
 357#define MAX_SCHEDULE_TIMEOUT    LONG_MAX
 358extern signed long schedule_timeout(signed long timeout);
 359extern signed long schedule_timeout_interruptible(signed long timeout);
 360extern signed long schedule_timeout_killable(signed long timeout);
 361extern signed long schedule_timeout_uninterruptible(signed long timeout);
 362asmlinkage void schedule(void);
 363extern void schedule_preempt_disabled(void);
 364extern int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner);
 365
 366struct nsproxy;
 367struct user_namespace;
 368
 369/*
 370 * Default maximum number of active map areas, this limits the number of vmas
 371 * per mm struct. Users can overwrite this number by sysctl but there is a
 372 * problem.
 373 *
 374 * When a program's coredump is generated as ELF format, a section is created
 375 * per a vma. In ELF, the number of sections is represented in unsigned short.
 376 * This means the number of sections should be smaller than 65535 at coredump.
 377 * Because the kernel adds some informative sections to a image of program at
 378 * generating coredump, we need some margin. The number of extra sections is
 379 * 1-3 now and depends on arch. We use "5" as safe margin, here.
 380 */
 381#define MAPCOUNT_ELF_CORE_MARGIN        (5)
 382#define DEFAULT_MAX_MAP_COUNT   (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)
 383
 384extern int sysctl_max_map_count;
 385
 386#include <linux/aio.h>
 387
 388#ifdef CONFIG_MMU
 389extern void arch_pick_mmap_layout(struct mm_struct *mm);
 390extern unsigned long
 391arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
 392                       unsigned long, unsigned long);
 393extern unsigned long
 394arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 395                          unsigned long len, unsigned long pgoff,
 396                          unsigned long flags);
 397extern void arch_unmap_area(struct mm_struct *, unsigned long);
 398extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long);
 399#else
 400static inline void arch_pick_mmap_layout(struct mm_struct *mm) {}
 401#endif
 402
 403
 404extern void set_dumpable(struct mm_struct *mm, int value);
 405extern int get_dumpable(struct mm_struct *mm);
 406
 407/* mm flags */
 408/* dumpable bits */
 409#define MMF_DUMPABLE      0  /* core dump is permitted */
 410#define MMF_DUMP_SECURELY 1  /* core file is readable only by root */
 411
 412#define MMF_DUMPABLE_BITS 2
 413#define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)
 414
 415/* coredump filter bits */
 416#define MMF_DUMP_ANON_PRIVATE   2
 417#define MMF_DUMP_ANON_SHARED    3
 418#define MMF_DUMP_MAPPED_PRIVATE 4
 419#define MMF_DUMP_MAPPED_SHARED  5
 420#define MMF_DUMP_ELF_HEADERS    6
 421#define MMF_DUMP_HUGETLB_PRIVATE 7
 422#define MMF_DUMP_HUGETLB_SHARED  8
 423
 424#define MMF_DUMP_FILTER_SHIFT   MMF_DUMPABLE_BITS
 425#define MMF_DUMP_FILTER_BITS    7
 426#define MMF_DUMP_FILTER_MASK \
 427        (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
 428#define MMF_DUMP_FILTER_DEFAULT \
 429        ((1 << MMF_DUMP_ANON_PRIVATE) | (1 << MMF_DUMP_ANON_SHARED) |\
 430         (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
 431
 432#ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
 433# define MMF_DUMP_MASK_DEFAULT_ELF      (1 << MMF_DUMP_ELF_HEADERS)
 434#else
 435# define MMF_DUMP_MASK_DEFAULT_ELF      0
 436#endif
 437                                        /* leave room for more dump flags */
 438#define MMF_VM_MERGEABLE        16      /* KSM may merge identical pages */
 439#define MMF_VM_HUGEPAGE         17      /* set when VM_HUGEPAGE is set on vma */
 440
 441#define MMF_INIT_MASK           (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)
 442
 443struct sighand_struct {
 444        atomic_t                count;
 445        struct k_sigaction      action[_NSIG];
 446        spinlock_t              siglock;
 447        wait_queue_head_t       signalfd_wqh;
 448};
 449
 450struct pacct_struct {
 451        int                     ac_flag;
 452        long                    ac_exitcode;
 453        unsigned long           ac_mem;
 454        cputime_t               ac_utime, ac_stime;
 455        unsigned long           ac_minflt, ac_majflt;
 456};
 457
 458struct cpu_itimer {
 459        cputime_t expires;
 460        cputime_t incr;
 461        u32 error;
 462        u32 incr_error;
 463};
 464
 465/**
 466 * struct task_cputime - collected CPU time counts
 467 * @utime:              time spent in user mode, in &cputime_t units
 468 * @stime:              time spent in kernel mode, in &cputime_t units
 469 * @sum_exec_runtime:   total time spent on the CPU, in nanoseconds
 470 *
 471 * This structure groups together three kinds of CPU time that are
 472 * tracked for threads and thread groups.  Most things considering
 473 * CPU time want to group these counts together and treat all three
 474 * of them in parallel.
 475 */
 476struct task_cputime {
 477        cputime_t utime;
 478        cputime_t stime;
 479        unsigned long long sum_exec_runtime;
 480};
 481/* Alternate field names when used to cache expirations. */
 482#define prof_exp        stime
 483#define virt_exp        utime
 484#define sched_exp       sum_exec_runtime
 485
 486#define INIT_CPUTIME    \
 487        (struct task_cputime) {                                 \
 488                .utime = 0,                                     \
 489                .stime = 0,                                     \
 490                .sum_exec_runtime = 0,                          \
 491        }
 492
 493/*
 494 * Disable preemption until the scheduler is running.
 495 * Reset by start_kernel()->sched_init()->init_idle().
 496 *
 497 * We include PREEMPT_ACTIVE to avoid cond_resched() from working
 498 * before the scheduler is active -- see should_resched().
 499 */
 500#define INIT_PREEMPT_COUNT      (1 + PREEMPT_ACTIVE)
 501
 502/**
 503 * struct thread_group_cputimer - thread group interval timer counts
 504 * @cputime:            thread group interval timers.
 505 * @running:            non-zero when there are timers running and
 506 *                      @cputime receives updates.
 507 * @lock:               lock for fields in this struct.
 508 *
 509 * This structure contains the version of task_cputime, above, that is
 510 * used for thread group CPU timer calculations.
 511 */
 512struct thread_group_cputimer {
 513        struct task_cputime cputime;
 514        int running;
 515        raw_spinlock_t lock;
 516};
 517
 518#include <linux/rwsem.h>
 519struct autogroup;
 520
 521/*
 522 * NOTE! "signal_struct" does not have its own
 523 * locking, because a shared signal_struct always
 524 * implies a shared sighand_struct, so locking
 525 * sighand_struct is always a proper superset of
 526 * the locking of signal_struct.
 527 */
 528struct signal_struct {
 529        atomic_t                sigcnt;
 530        atomic_t                live;
 531        int                     nr_threads;
 532
 533        wait_queue_head_t       wait_chldexit;  /* for wait4() */
 534
 535        /* current thread group signal load-balancing target: */
 536        struct task_struct      *curr_target;
 537
 538        /* shared signal handling: */
 539        struct sigpending       shared_pending;
 540
 541        /* thread group exit support */
 542        int                     group_exit_code;
 543        /* overloaded:
 544         * - notify group_exit_task when ->count is equal to notify_count
 545         * - everyone except group_exit_task is stopped during signal delivery
 546         *   of fatal signals, group_exit_task processes the signal.
 547         */
 548        int                     notify_count;
 549        struct task_struct      *group_exit_task;
 550
 551        /* thread group stop support, overloads group_exit_code too */
 552        int                     group_stop_count;
 553        unsigned int            flags; /* see SIGNAL_* flags below */
 554
 555        /*
 556         * PR_SET_CHILD_SUBREAPER marks a process, like a service
 557         * manager, to re-parent orphan (double-forking) child processes
 558         * to this process instead of 'init'. The service manager is
 559         * able to receive SIGCHLD signals and is able to investigate
 560         * the process until it calls wait(). All children of this
 561         * process will inherit a flag if they should look for a
 562         * child_subreaper process at exit.
 563         */
 564        unsigned int            is_child_subreaper:1;
 565        unsigned int            has_child_subreaper:1;
 566
 567        /* POSIX.1b Interval Timers */
 568        struct list_head posix_timers;
 569
 570        /* ITIMER_REAL timer for the process */
 571        struct hrtimer real_timer;
 572        struct pid *leader_pid;
 573        ktime_t it_real_incr;
 574
 575        /*
 576         * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
 577         * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
 578         * values are defined to 0 and 1 respectively
 579         */
 580        struct cpu_itimer it[2];
 581
 582        /*
 583         * Thread group totals for process CPU timers.
 584         * See thread_group_cputimer(), et al, for details.
 585         */
 586        struct thread_group_cputimer cputimer;
 587
 588        /* Earliest-expiration cache. */
 589        struct task_cputime cputime_expires;
 590
 591        struct list_head cpu_timers[3];
 592
 593        struct pid *tty_old_pgrp;
 594
 595        /* boolean value for session group leader */
 596        int leader;
 597
 598        struct tty_struct *tty; /* NULL if no tty */
 599
 600#ifdef CONFIG_SCHED_AUTOGROUP
 601        struct autogroup *autogroup;
 602#endif
 603        /*
 604         * Cumulative resource counters for dead threads in the group,
 605         * and for reaped dead child processes forked by this group.
 606         * Live threads maintain their own counters and add to these
 607         * in __exit_signal, except for the group leader.
 608         */
 609        cputime_t utime, stime, cutime, cstime;
 610        cputime_t gtime;
 611        cputime_t cgtime;
 612#ifndef CONFIG_VIRT_CPU_ACCOUNTING
 613        cputime_t prev_utime, prev_stime;
 614#endif
 615        unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
 616        unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
 617        unsigned long inblock, oublock, cinblock, coublock;
 618        unsigned long maxrss, cmaxrss;
 619        struct task_io_accounting ioac;
 620
 621        /*
 622         * Cumulative ns of schedule CPU time fo dead threads in the
 623         * group, not including a zombie group leader, (This only differs
 624         * from jiffies_to_ns(utime + stime) if sched_clock uses something
 625         * other than jiffies.)
 626         */
 627        unsigned long long sum_sched_runtime;
 628
 629        /*
 630         * We don't bother to synchronize most readers of this at all,
 631         * because there is no reader checking a limit that actually needs
 632         * to get both rlim_cur and rlim_max atomically, and either one
 633         * alone is a single word that can safely be read normally.
 634         * getrlimit/setrlimit use task_lock(current->group_leader) to
 635         * protect this instead of the siglock, because they really
 636         * have no need to disable irqs.
 637         */
 638        struct rlimit rlim[RLIM_NLIMITS];
 639
 640#ifdef CONFIG_BSD_PROCESS_ACCT
 641        struct pacct_struct pacct;      /* per-process accounting information */
 642#endif
 643#ifdef CONFIG_TASKSTATS
 644        struct taskstats *stats;
 645#endif
 646#ifdef CONFIG_AUDIT
 647        unsigned audit_tty;
 648        struct tty_audit_buf *tty_audit_buf;
 649#endif
 650#ifdef CONFIG_CGROUPS
 651        /*
 652         * group_rwsem prevents new tasks from entering the threadgroup and
 653         * member tasks from exiting,a more specifically, setting of
 654         * PF_EXITING.  fork and exit paths are protected with this rwsem
 655         * using threadgroup_change_begin/end().  Users which require
 656         * threadgroup to remain stable should use threadgroup_[un]lock()
 657         * which also takes care of exec path.  Currently, cgroup is the
 658         * only user.
 659         */
 660        struct rw_semaphore group_rwsem;
 661#endif
 662
 663        int oom_adj;            /* OOM kill score adjustment (bit shift) */
 664        int oom_score_adj;      /* OOM kill score adjustment */
 665        int oom_score_adj_min;  /* OOM kill score adjustment minimum value.
 666                                 * Only settable by CAP_SYS_RESOURCE. */
 667
 668        struct mutex cred_guard_mutex;  /* guard against foreign influences on
 669                                         * credential calculations
 670                                         * (notably. ptrace) */
 671};
 672
 673/* Context switch must be unlocked if interrupts are to be enabled */
 674#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
 675# define __ARCH_WANT_UNLOCKED_CTXSW
 676#endif
 677
 678/*
 679 * Bits in flags field of signal_struct.
 680 */
 681#define SIGNAL_STOP_STOPPED     0x00000001 /* job control stop in effect */
 682#define SIGNAL_STOP_CONTINUED   0x00000002 /* SIGCONT since WCONTINUED reap */
 683#define SIGNAL_GROUP_EXIT       0x00000004 /* group exit in progress */
 684/*
 685 * Pending notifications to parent.
 686 */
 687#define SIGNAL_CLD_STOPPED      0x00000010
 688#define SIGNAL_CLD_CONTINUED    0x00000020
 689#define SIGNAL_CLD_MASK         (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
 690
 691#define SIGNAL_UNKILLABLE       0x00000040 /* for init: ignore fatal signals */
 692
 693/* If true, all threads except ->group_exit_task have pending SIGKILL */
 694static inline int signal_group_exit(const struct signal_struct *sig)
 695{
 696        return  (sig->flags & SIGNAL_GROUP_EXIT) ||
 697                (sig->group_exit_task != NULL);
 698}
 699
 700/*
 701 * Some day this will be a full-fledged user tracking system..
 702 */
 703struct user_struct {
 704        atomic_t __count;       /* reference count */
 705        atomic_t processes;     /* How many processes does this user have? */
 706        atomic_t files;         /* How many open files does this user have? */
 707        atomic_t sigpending;    /* How many pending signals does this user have? */
 708#ifdef CONFIG_INOTIFY_USER
 709        atomic_t inotify_watches; /* How many inotify watches does this user have? */
 710        atomic_t inotify_devs;  /* How many inotify devs does this user have opened? */
 711#endif
 712#ifdef CONFIG_FANOTIFY
 713        atomic_t fanotify_listeners;
 714#endif
 715#ifdef CONFIG_EPOLL
 716        atomic_long_t epoll_watches; /* The number of file descriptors currently watched */
 717#endif
 718#ifdef CONFIG_POSIX_MQUEUE
 719        /* protected by mq_lock */
 720        unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */
 721#endif
 722        unsigned long locked_shm; /* How many pages of mlocked shm ? */
 723
 724#ifdef CONFIG_KEYS
 725        struct key *uid_keyring;        /* UID specific keyring */
 726        struct key *session_keyring;    /* UID's default session keyring */
 727#endif
 728
 729        /* Hash table maintenance information */
 730        struct hlist_node uidhash_node;
 731        uid_t uid;
 732        struct user_namespace *user_ns;
 733
 734#ifdef CONFIG_PERF_EVENTS
 735        atomic_long_t locked_vm;
 736#endif
 737};
 738
 739extern int uids_sysfs_init(void);
 740
 741extern struct user_struct *find_user(uid_t);
 742
 743extern struct user_struct root_user;
 744#define INIT_USER (&root_user)
 745
 746
 747struct backing_dev_info;
 748struct reclaim_state;
 749
 750#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
 751struct sched_info {
 752        /* cumulative counters */
 753        unsigned long pcount;         /* # of times run on this cpu */
 754        unsigned long long run_delay; /* time spent waiting on a runqueue */
 755
 756        /* timestamps */
 757        unsigned long long last_arrival,/* when we last ran on a cpu */
 758                           last_queued; /* when we were last queued to run */
 759};
 760#endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */
 761
 762#ifdef CONFIG_TASK_DELAY_ACCT
 763struct task_delay_info {
 764        spinlock_t      lock;
 765        unsigned int    flags;  /* Private per-task flags */
 766
 767        /* For each stat XXX, add following, aligned appropriately
 768         *
 769         * struct timespec XXX_start, XXX_end;
 770         * u64 XXX_delay;
 771         * u32 XXX_count;
 772         *
 773         * Atomicity of updates to XXX_delay, XXX_count protected by
 774         * single lock above (split into XXX_lock if contention is an issue).
 775         */
 776
 777        /*
 778         * XXX_count is incremented on every XXX operation, the delay
 779         * associated with the operation is added to XXX_delay.
 780         * XXX_delay contains the accumulated delay time in nanoseconds.
 781         */
 782        struct timespec blkio_start, blkio_end; /* Shared by blkio, swapin */
 783        u64 blkio_delay;        /* wait for sync block io completion */
 784        u64 swapin_delay;       /* wait for swapin block io completion */
 785        u32 blkio_count;        /* total count of the number of sync block */
 786                                /* io operations performed */
 787        u32 swapin_count;       /* total count of the number of swapin block */
 788                                /* io operations performed */
 789
 790        struct timespec freepages_start, freepages_end;
 791        u64 freepages_delay;    /* wait for memory reclaim */
 792        u32 freepages_count;    /* total count of memory reclaim */
 793};
 794#endif  /* CONFIG_TASK_DELAY_ACCT */
 795
 796static inline int sched_info_on(void)
 797{
 798#ifdef CONFIG_SCHEDSTATS
 799        return 1;
 800#elif defined(CONFIG_TASK_DELAY_ACCT)
 801        extern int delayacct_on;
 802        return delayacct_on;
 803#else
 804        return 0;
 805#endif
 806}
 807
 808enum cpu_idle_type {
 809        CPU_IDLE,
 810        CPU_NOT_IDLE,
 811        CPU_NEWLY_IDLE,
 812        CPU_MAX_IDLE_TYPES
 813};
 814
 815/*
 816 * Increase resolution of nice-level calculations for 64-bit architectures.
 817 * The extra resolution improves shares distribution and load balancing of
 818 * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
 819 * hierarchies, especially on larger systems. This is not a user-visible change
 820 * and does not change the user-interface for setting shares/weights.
 821 *
 822 * We increase resolution only if we have enough bits to allow this increased
 823 * resolution (i.e. BITS_PER_LONG > 32). The costs for increasing resolution
 824 * when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the
 825 * increased costs.
 826 */
 827#if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load  */
 828# define SCHED_LOAD_RESOLUTION  10
 829# define scale_load(w)          ((w) << SCHED_LOAD_RESOLUTION)
 830# define scale_load_down(w)     ((w) >> SCHED_LOAD_RESOLUTION)
 831#else
 832# define SCHED_LOAD_RESOLUTION  0
 833# define scale_load(w)          (w)
 834# define scale_load_down(w)     (w)
 835#endif
 836
 837#define SCHED_LOAD_SHIFT        (10 + SCHED_LOAD_RESOLUTION)
 838#define SCHED_LOAD_SCALE        (1L << SCHED_LOAD_SHIFT)
 839
 840/*
 841 * Increase resolution of cpu_power calculations
 842 */
 843#define SCHED_POWER_SHIFT       10
 844#define SCHED_POWER_SCALE       (1L << SCHED_POWER_SHIFT)
 845
 846/*
 847 * sched-domains (multiprocessor balancing) declarations:
 848 */
 849#ifdef CONFIG_SMP
 850#define SD_LOAD_BALANCE         0x0001  /* Do load balancing on this domain. */
 851#define SD_BALANCE_NEWIDLE      0x0002  /* Balance when about to become idle */
 852#define SD_BALANCE_EXEC         0x0004  /* Balance on exec */
 853#define SD_BALANCE_FORK         0x0008  /* Balance on fork, clone */
 854#define SD_BALANCE_WAKE         0x0010  /* Balance on wakeup */
 855#define SD_WAKE_AFFINE          0x0020  /* Wake task to waking CPU */
 856#define SD_PREFER_LOCAL         0x0040  /* Prefer to keep tasks local to this domain */
 857#define SD_SHARE_CPUPOWER       0x0080  /* Domain members share cpu power */
 858#define SD_POWERSAVINGS_BALANCE 0x0100  /* Balance for power savings */
 859#define SD_SHARE_PKG_RESOURCES  0x0200  /* Domain members share cpu pkg resources */
 860#define SD_SERIALIZE            0x0400  /* Only a single load balancing instance */
 861#define SD_ASYM_PACKING         0x0800  /* Place busy groups earlier in the domain */
 862#define SD_PREFER_SIBLING       0x1000  /* Prefer to place tasks in a sibling domain */
 863#define SD_OVERLAP              0x2000  /* sched_domains of this level overlap */
 864
 865enum powersavings_balance_level {
 866        POWERSAVINGS_BALANCE_NONE = 0,  /* No power saving load balance */
 867        POWERSAVINGS_BALANCE_BASIC,     /* Fill one thread/core/package
 868                                         * first for long running threads
 869                                         */
 870        POWERSAVINGS_BALANCE_WAKEUP,    /* Also bias task wakeups to semi-idle
 871                                         * cpu package for power savings
 872                                         */
 873        MAX_POWERSAVINGS_BALANCE_LEVELS
 874};
 875
 876extern int sched_mc_power_savings, sched_smt_power_savings;
 877
 878static inline int sd_balance_for_mc_power(void)
 879{
 880        if (sched_smt_power_savings)
 881                return SD_POWERSAVINGS_BALANCE;
 882
 883        if (!sched_mc_power_savings)
 884                return SD_PREFER_SIBLING;
 885
 886        return 0;
 887}
 888
 889static inline int sd_balance_for_package_power(void)
 890{
 891        if (sched_mc_power_savings | sched_smt_power_savings)
 892                return SD_POWERSAVINGS_BALANCE;
 893
 894        return SD_PREFER_SIBLING;
 895}
 896
 897extern int __weak arch_sd_sibiling_asym_packing(void);
 898
 899/*
 900 * Optimise SD flags for power savings:
 901 * SD_BALANCE_NEWIDLE helps aggressive task consolidation and power savings.
 902 * Keep default SD flags if sched_{smt,mc}_power_saving=0
 903 */
 904
 905static inline int sd_power_saving_flags(void)
 906{
 907        if (sched_mc_power_savings | sched_smt_power_savings)
 908                return SD_BALANCE_NEWIDLE;
 909
 910        return 0;
 911}
 912
 913struct sched_group_power {
 914        atomic_t ref;
 915        /*
 916         * CPU power of this group, SCHED_LOAD_SCALE being max power for a
 917         * single CPU.
 918         */
 919        unsigned int power, power_orig;
 920        unsigned long next_update;
 921        /*
 922         * Number of busy cpus in this group.
 923         */
 924        atomic_t nr_busy_cpus;
 925};
 926
 927struct sched_group {
 928        struct sched_group *next;       /* Must be a circular list */
 929        atomic_t ref;
 930
 931        unsigned int group_weight;
 932        struct sched_group_power *sgp;
 933
 934        /*
 935         * The CPUs this group covers.
 936         *
 937         * NOTE: this field is variable length. (Allocated dynamically
 938         * by attaching extra space to the end of the structure,
 939         * depending on how many CPUs the kernel has booted up with)
 940         */
 941        unsigned long cpumask[0];
 942};
 943
 944static inline struct cpumask *sched_group_cpus(struct sched_group *sg)
 945{
 946        return to_cpumask(sg->cpumask);
 947}
 948
 949/**
 950 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
 951 * @group: The group whose first cpu is to be returned.
 952 */
 953static inline unsigned int group_first_cpu(struct sched_group *group)
 954{
 955        return cpumask_first(sched_group_cpus(group));
 956}
 957
 958struct sched_domain_attr {
 959        int relax_domain_level;
 960};
 961
 962#define SD_ATTR_INIT    (struct sched_domain_attr) {    \
 963        .relax_domain_level = -1,                       \
 964}
 965
 966extern int sched_domain_level_max;
 967
 968struct sched_domain {
 969        /* These fields must be setup */
 970        struct sched_domain *parent;    /* top domain must be null terminated */
 971        struct sched_domain *child;     /* bottom domain must be null terminated */
 972        struct sched_group *groups;     /* the balancing groups of the domain */
 973        unsigned long min_interval;     /* Minimum balance interval ms */
 974        unsigned long max_interval;     /* Maximum balance interval ms */
 975        unsigned int busy_factor;       /* less balancing by factor if busy */
 976        unsigned int imbalance_pct;     /* No balance until over watermark */
 977        unsigned int cache_nice_tries;  /* Leave cache hot tasks for # tries */
 978        unsigned int busy_idx;
 979        unsigned int idle_idx;
 980        unsigned int newidle_idx;
 981        unsigned int wake_idx;
 982        unsigned int forkexec_idx;
 983        unsigned int smt_gain;
 984        int flags;                      /* See SD_* */
 985        int level;
 986
 987        /* Runtime fields. */
 988        unsigned long last_balance;     /* init to jiffies. units in jiffies */
 989        unsigned int balance_interval;  /* initialise to 1. units in ms. */
 990        unsigned int nr_balance_failed; /* initialise to 0 */
 991
 992        u64 last_update;
 993
 994#ifdef CONFIG_SCHEDSTATS
 995        /* load_balance() stats */
 996        unsigned int lb_count[CPU_MAX_IDLE_TYPES];
 997        unsigned int lb_failed[CPU_MAX_IDLE_TYPES];
 998        unsigned int lb_balanced[CPU_MAX_IDLE_TYPES];
 999        unsigned int lb_imbalance[CPU_MAX_IDLE_TYPES];
1000        unsigned int lb_gained[CPU_MAX_IDLE_TYPES];
1001        unsigned int lb_hot_gained[CPU_MAX_IDLE_TYPES];
1002        unsigned int lb_nobusyg[CPU_MAX_IDLE_TYPES];
1003        unsigned int lb_nobusyq[CPU_MAX_IDLE_TYPES];
1004
1005        /* Active load balancing */
1006        unsigned int alb_count;
1007        unsigned int alb_failed;
1008        unsigned int alb_pushed;
1009
1010        /* SD_BALANCE_EXEC stats */
1011        unsigned int sbe_count;
1012        unsigned int sbe_balanced;
1013        unsigned int sbe_pushed;
1014
1015        /* SD_BALANCE_FORK stats */
1016        unsigned int sbf_count;
1017        unsigned int sbf_balanced;
1018        unsigned int sbf_pushed;
1019
1020        /* try_to_wake_up() stats */
1021        unsigned int ttwu_wake_remote;
1022        unsigned int ttwu_move_affine;
1023        unsigned int ttwu_move_balance;
1024#endif
1025#ifdef CONFIG_SCHED_DEBUG
1026        char *name;
1027#endif
1028        union {
1029                void *private;          /* used during construction */
1030                struct rcu_head rcu;    /* used during destruction */
1031        };
1032
1033        unsigned int span_weight;
1034        /*
1035         * Span of all CPUs in this domain.
1036         *
1037         * NOTE: this field is variable length. (Allocated dynamically
1038         * by attaching extra space to the end of the structure,
1039         * depending on how many CPUs the kernel has booted up with)
1040         */
1041        unsigned long span[0];
1042};
1043
1044static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
1045{
1046        return to_cpumask(sd->span);
1047}
1048
1049extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
1050                                    struct sched_domain_attr *dattr_new);
1051
1052/* Allocate an array of sched domains, for partition_sched_domains(). */
1053cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
1054void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
1055
1056/* Test a flag in parent sched domain */
1057static inline int test_sd_parent(struct sched_domain *sd, int flag)
1058{
1059        if (sd->parent && (sd->parent->flags & flag))
1060                return 1;
1061
1062        return 0;
1063}
1064
1065unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu);
1066unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu);
1067
1068bool cpus_share_cache(int this_cpu, int that_cpu);
1069
1070#else /* CONFIG_SMP */
1071
1072struct sched_domain_attr;
1073
1074static inline void
1075partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
1076                        struct sched_domain_attr *dattr_new)
1077{
1078}
1079
1080static inline bool cpus_share_cache(int this_cpu, int that_cpu)
1081{
1082        return true;
1083}
1084
1085#endif  /* !CONFIG_SMP */
1086
1087
1088struct io_context;                      /* See blkdev.h */
1089
1090
1091#ifdef ARCH_HAS_PREFETCH_SWITCH_STACK
1092extern void prefetch_stack(struct task_struct *t);
1093#else
1094static inline void prefetch_stack(struct task_struct *t) { }
1095#endif
1096
1097struct audit_context;           /* See audit.c */
1098struct mempolicy;
1099struct pipe_inode_info;
1100struct uts_namespace;
1101
1102struct rq;
1103struct sched_domain;
1104
1105/*
1106 * wake flags
1107 */
1108#define WF_SYNC         0x01            /* waker goes to sleep after wakup */
1109#define WF_FORK         0x02            /* child wakeup after fork */
1110#define WF_MIGRATED     0x04            /* internal use, task got migrated */
1111
1112#define ENQUEUE_WAKEUP          1
1113#define ENQUEUE_HEAD            2
1114#ifdef CONFIG_SMP
1115#define ENQUEUE_WAKING          4       /* sched_class::task_waking was called */
1116#else
1117#define ENQUEUE_WAKING          0
1118#endif
1119
1120#define DEQUEUE_SLEEP           1
1121
1122struct sched_class {
1123        const struct sched_class *next;
1124
1125        void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
1126        void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
1127        void (*yield_task) (struct rq *rq);
1128        bool (*yield_to_task) (struct rq *rq, struct task_struct *p, bool preempt);
1129
1130        void (*check_preempt_curr) (struct rq *rq, struct task_struct *p, int flags);
1131
1132        struct task_struct * (*pick_next_task) (struct rq *rq);
1133        void (*put_prev_task) (struct rq *rq, struct task_struct *p);
1134
1135#ifdef CONFIG_SMP
1136        int  (*select_task_rq)(struct task_struct *p, int sd_flag, int flags);
1137
1138        void (*pre_schedule) (struct rq *this_rq, struct task_struct *task);
1139        void (*post_schedule) (struct rq *this_rq);
1140        void (*task_waking) (struct task_struct *task);
1141        void (*task_woken) (struct rq *this_rq, struct task_struct *task);
1142
1143        void (*set_cpus_allowed)(struct task_struct *p,
1144                                 const struct cpumask *newmask);
1145
1146        void (*rq_online)(struct rq *rq);
1147        void (*rq_offline)(struct rq *rq);
1148#endif
1149
1150        void (*set_curr_task) (struct rq *rq);
1151        void (*task_tick) (struct rq *rq, struct task_struct *p, int queued);
1152        void (*task_fork) (struct task_struct *p);
1153
1154        void (*switched_from) (struct rq *this_rq, struct task_struct *task);
1155        void (*switched_to) (struct rq *this_rq, struct task_struct *task);
1156        void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
1157                             int oldprio);
1158
1159        unsigned int (*get_rr_interval) (struct rq *rq,
1160                                         struct task_struct *task);
1161
1162#ifdef CONFIG_FAIR_GROUP_SCHED
1163        void (*task_move_group) (struct task_struct *p, int on_rq);
1164#endif
1165};
1166
1167struct load_weight {
1168        unsigned long weight, inv_weight;
1169};
1170
1171#ifdef CONFIG_SCHEDSTATS
1172struct sched_statistics {
1173        u64                     wait_start;
1174        u64                     wait_max;
1175        u64                     wait_count;
1176        u64                     wait_sum;
1177        u64                     iowait_count;
1178        u64                     iowait_sum;
1179
1180        u64                     sleep_start;
1181        u64                     sleep_max;
1182        s64                     sum_sleep_runtime;
1183
1184        u64                     block_start;
1185        u64                     block_max;
1186        u64                     exec_max;
1187        u64                     slice_max;
1188
1189        u64                     nr_migrations_cold;
1190        u64                     nr_failed_migrations_affine;
1191        u64                     nr_failed_migrations_running;
1192        u64                     nr_failed_migrations_hot;
1193        u64                     nr_forced_migrations;
1194
1195        u64                     nr_wakeups;
1196        u64                     nr_wakeups_sync;
1197        u64                     nr_wakeups_migrate;
1198        u64                     nr_wakeups_local;
1199        u64                     nr_wakeups_remote;
1200        u64                     nr_wakeups_affine;
1201        u64                     nr_wakeups_affine_attempts;
1202        u64                     nr_wakeups_passive;
1203        u64                     nr_wakeups_idle;
1204};
1205#endif
1206
1207struct sched_entity {
1208        struct load_weight      load;           /* for load-balancing */
1209        struct rb_node          run_node;
1210        struct list_head        group_node;
1211        unsigned int            on_rq;
1212
1213        u64                     exec_start;
1214        u64                     sum_exec_runtime;
1215        u64                     vruntime;
1216        u64                     prev_sum_exec_runtime;
1217
1218        u64                     nr_migrations;
1219
1220#ifdef CONFIG_SCHEDSTATS
1221        struct sched_statistics statistics;
1222#endif
1223
1224#ifdef CONFIG_FAIR_GROUP_SCHED
1225        struct sched_entity     *parent;
1226        /* rq on which this entity is (to be) queued: */
1227        struct cfs_rq           *cfs_rq;
1228        /* rq "owned" by this entity/group: */
1229        struct cfs_rq           *my_q;
1230#endif
1231};
1232
1233struct sched_rt_entity {
1234        struct list_head run_list;
1235        unsigned long timeout;
1236        unsigned int time_slice;
1237        int nr_cpus_allowed;
1238
1239        struct sched_rt_entity *back;
1240#ifdef CONFIG_RT_GROUP_SCHED
1241        struct sched_rt_entity  *parent;
1242        /* rq on which this entity is (to be) queued: */
1243        struct rt_rq            *rt_rq;
1244        /* rq "owned" by this entity/group: */
1245        struct rt_rq            *my_q;
1246#endif
1247};
1248
1249/*
1250 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
1251 * Timeslices get refilled after they expire.
1252 */
1253#define RR_TIMESLICE            (100 * HZ / 1000)
1254
1255struct rcu_node;
1256
1257enum perf_event_task_context {
1258        perf_invalid_context = -1,
1259        perf_hw_context = 0,
1260        perf_sw_context,
1261        perf_nr_task_contexts,
1262};
1263
1264struct task_struct {
1265        volatile long state;    /* -1 unrunnable, 0 runnable, >0 stopped */
1266        void *stack;
1267        atomic_t usage;
1268        unsigned int flags;     /* per process flags, defined below */
1269        unsigned int ptrace;
1270
1271#ifdef CONFIG_SMP
1272        struct llist_node wake_entry;
1273        int on_cpu;
1274#endif
1275        int on_rq;
1276
1277        int prio, static_prio, normal_prio;
1278        unsigned int rt_priority;
1279        const struct sched_class *sched_class;
1280        struct sched_entity se;
1281        struct sched_rt_entity rt;
1282
1283#ifdef CONFIG_PREEMPT_NOTIFIERS
1284        /* list of struct preempt_notifier: */
1285        struct hlist_head preempt_notifiers;
1286#endif
1287
1288        /*
1289         * fpu_counter contains the number of consecutive context switches
1290         * that the FPU is used. If this is over a threshold, the lazy fpu
1291         * saving becomes unlazy to save the trap. This is an unsigned char
1292         * so that after 256 times the counter wraps and the behavior turns
1293         * lazy again; this to deal with bursty apps that only use FPU for
1294         * a short time
1295         */
1296        unsigned char fpu_counter;
1297#ifdef CONFIG_BLK_DEV_IO_TRACE
1298        unsigned int btrace_seq;
1299#endif
1300
1301        unsigned int policy;
1302        cpumask_t cpus_allowed;
1303
1304#ifdef CONFIG_PREEMPT_RCU
1305        int rcu_read_lock_nesting;
1306        char rcu_read_unlock_special;
1307        struct list_head rcu_node_entry;
1308#endif /* #ifdef CONFIG_PREEMPT_RCU */
1309#ifdef CONFIG_TREE_PREEMPT_RCU
1310        struct rcu_node *rcu_blocked_node;
1311#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
1312#ifdef CONFIG_RCU_BOOST
1313        struct rt_mutex *rcu_boost_mutex;
1314#endif /* #ifdef CONFIG_RCU_BOOST */
1315
1316#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1317        struct sched_info sched_info;
1318#endif
1319
1320        struct list_head tasks;
1321#ifdef CONFIG_SMP
1322        struct plist_node pushable_tasks;
1323#endif
1324
1325        struct mm_struct *mm, *active_mm;
1326#ifdef CONFIG_COMPAT_BRK
1327        unsigned brk_randomized:1;
1328#endif
1329#if defined(SPLIT_RSS_COUNTING)
1330        struct task_rss_stat    rss_stat;
1331#endif
1332/* task state */
1333        int exit_state;
1334        int exit_code, exit_signal;
1335        int pdeath_signal;  /*  The signal sent when the parent dies  */
1336        unsigned int jobctl;    /* JOBCTL_*, siglock protected */
1337        /* ??? */
1338        unsigned int personality;
1339        unsigned did_exec:1;
1340        unsigned in_execve:1;   /* Tell the LSMs that the process is doing an
1341                                 * execve */
1342        unsigned in_iowait:1;
1343
1344
1345        /* Revert to default priority/policy when forking */
1346        unsigned sched_reset_on_fork:1;
1347        unsigned sched_contributes_to_load:1;
1348
1349#ifdef CONFIG_GENERIC_HARDIRQS
1350        /* IRQ handler threads */
1351        unsigned irq_thread:1;
1352#endif
1353
1354        pid_t pid;
1355        pid_t tgid;
1356
1357#ifdef CONFIG_CC_STACKPROTECTOR
1358        /* Canary value for the -fstack-protector gcc feature */
1359        unsigned long stack_canary;
1360#endif
1361
1362        /* 
1363         * pointers to (original) parent process, youngest child, younger sibling,
1364         * older sibling, respectively.  (p->father can be replaced with 
1365         * p->real_parent->pid)
1366         */
1367        struct task_struct __rcu *real_parent; /* real parent process */
1368        struct task_struct __rcu *parent; /* recipient of SIGCHLD, wait4() reports */
1369        /*
1370         * children/sibling forms the list of my natural children
1371         */
1372        struct list_head children;      /* list of my children */
1373        struct list_head sibling;       /* linkage in my parent's children list */
1374        struct task_struct *group_leader;       /* threadgroup leader */
1375
1376        /*
1377         * ptraced is the list of tasks this task is using ptrace on.
1378         * This includes both natural children and PTRACE_ATTACH targets.
1379         * p->ptrace_entry is p's link on the p->parent->ptraced list.
1380         */
1381        struct list_head ptraced;
1382        struct list_head ptrace_entry;
1383
1384        /* PID/PID hash table linkage. */
1385        struct pid_link pids[PIDTYPE_MAX];
1386        struct list_head thread_group;
1387
1388        struct completion *vfork_done;          /* for vfork() */
1389        int __user *set_child_tid;              /* CLONE_CHILD_SETTID */
1390        int __user *clear_child_tid;            /* CLONE_CHILD_CLEARTID */
1391
1392        cputime_t utime, stime, utimescaled, stimescaled;
1393        cputime_t gtime;
1394#ifndef CONFIG_VIRT_CPU_ACCOUNTING
1395        cputime_t prev_utime, prev_stime;
1396#endif
1397        unsigned long nvcsw, nivcsw; /* context switch counts */
1398        struct timespec start_time;             /* monotonic time */
1399        struct timespec real_start_time;        /* boot based time */
1400/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
1401        unsigned long min_flt, maj_flt;
1402
1403        struct task_cputime cputime_expires;
1404        struct list_head cpu_timers[3];
1405
1406/* process credentials */
1407        const struct cred __rcu *real_cred; /* objective and real subjective task
1408                                         * credentials (COW) */
1409        const struct cred __rcu *cred;  /* effective (overridable) subjective task
1410                                         * credentials (COW) */
1411        struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */
1412
1413        char comm[TASK_COMM_LEN]; /* executable name excluding path
1414                                     - access with [gs]et_task_comm (which lock
1415                                       it with task_lock())
1416                                     - initialized normally by setup_new_exec */
1417/* file system info */
1418        int link_count, total_link_count;
1419#ifdef CONFIG_SYSVIPC
1420/* ipc stuff */
1421        struct sysv_sem sysvsem;
1422#endif
1423#ifdef CONFIG_DETECT_HUNG_TASK
1424/* hung task detection */
1425        unsigned long last_switch_count;
1426#endif
1427/* CPU-specific state of this task */
1428        struct thread_struct thread;
1429/* filesystem information */
1430        struct fs_struct *fs;
1431/* open file information */
1432        struct files_struct *files;
1433/* namespaces */
1434        struct nsproxy *nsproxy;
1435/* signal handlers */
1436        struct signal_struct *signal;
1437        struct sighand_struct *sighand;
1438
1439        sigset_t blocked, real_blocked;
1440        sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */
1441        struct sigpending pending;
1442
1443        unsigned long sas_ss_sp;
1444        size_t sas_ss_size;
1445        int (*notifier)(void *priv);
1446        void *notifier_data;
1447        sigset_t *notifier_mask;
1448        struct audit_context *audit_context;
1449#ifdef CONFIG_AUDITSYSCALL
1450        uid_t loginuid;
1451        unsigned int sessionid;
1452#endif
1453        seccomp_t seccomp;
1454
1455/* Thread group tracking */
1456        u32 parent_exec_id;
1457        u32 self_exec_id;
1458/* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed,
1459 * mempolicy */
1460        spinlock_t alloc_lock;
1461
1462        /* Protection of the PI data structures: */
1463        raw_spinlock_t pi_lock;
1464
1465#ifdef CONFIG_RT_MUTEXES
1466        /* PI waiters blocked on a rt_mutex held by this task */
1467        struct plist_head pi_waiters;
1468        /* Deadlock detection and priority inheritance handling */
1469        struct rt_mutex_waiter *pi_blocked_on;
1470#endif
1471
1472#ifdef CONFIG_DEBUG_MUTEXES
1473        /* mutex deadlock detection */
1474        struct mutex_waiter *blocked_on;
1475#endif
1476#ifdef CONFIG_TRACE_IRQFLAGS
1477        unsigned int irq_events;
1478        unsigned long hardirq_enable_ip;
1479        unsigned long hardirq_disable_ip;
1480        unsigned int hardirq_enable_event;
1481        unsigned int hardirq_disable_event;
1482        int hardirqs_enabled;
1483        int hardirq_context;
1484        unsigned long softirq_disable_ip;
1485        unsigned long softirq_enable_ip;
1486        unsigned int softirq_disable_event;
1487        unsigned int softirq_enable_event;
1488        int softirqs_enabled;
1489        int softirq_context;
1490#endif
1491#ifdef CONFIG_LOCKDEP
1492# define MAX_LOCK_DEPTH 48UL
1493        u64 curr_chain_key;
1494        int lockdep_depth;
1495        unsigned int lockdep_recursion;
1496        struct held_lock held_locks[MAX_LOCK_DEPTH];
1497        gfp_t lockdep_reclaim_gfp;
1498#endif
1499
1500/* journalling filesystem info */
1501        void *journal_info;
1502
1503/* stacked block device info */
1504        struct bio_list *bio_list;
1505
1506#ifdef CONFIG_BLOCK
1507/* stack plugging */
1508        struct blk_plug *plug;
1509#endif
1510
1511/* VM state */
1512        struct reclaim_state *reclaim_state;
1513
1514        struct backing_dev_info *backing_dev_info;
1515
1516        struct io_context *io_context;
1517
1518        unsigned long ptrace_message;
1519        siginfo_t *last_siginfo; /* For ptrace use.  */
1520        struct task_io_accounting ioac;
1521#if defined(CONFIG_TASK_XACCT)
1522        u64 acct_rss_mem1;      /* accumulated rss usage */
1523        u64 acct_vm_mem1;       /* accumulated virtual memory usage */
1524        cputime_t acct_timexpd; /* stime + utime since last update */
1525#endif
1526#ifdef CONFIG_CPUSETS
1527        nodemask_t mems_allowed;        /* Protected by alloc_lock */
1528        seqcount_t mems_allowed_seq;    /* Seqence no to catch updates */
1529        int cpuset_mem_spread_rotor;
1530        int cpuset_slab_spread_rotor;
1531#endif
1532#ifdef CONFIG_CGROUPS
1533        /* Control Group info protected by css_set_lock */
1534        struct css_set __rcu *cgroups;
1535        /* cg_list protected by css_set_lock and tsk->alloc_lock */
1536        struct list_head cg_list;
1537#endif
1538#ifdef CONFIG_FUTEX
1539        struct robust_list_head __user *robust_list;
1540#ifdef CONFIG_COMPAT
1541        struct compat_robust_list_head __user *compat_robust_list;
1542#endif
1543        struct list_head pi_state_list;
1544        struct futex_pi_state *pi_state_cache;
1545#endif
1546#ifdef CONFIG_PERF_EVENTS
1547        struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
1548        struct mutex perf_event_mutex;
1549        struct list_head perf_event_list;
1550#endif
1551#ifdef CONFIG_NUMA
1552        struct mempolicy *mempolicy;    /* Protected by alloc_lock */
1553        short il_next;
1554        short pref_node_fork;
1555#endif
1556        struct rcu_head rcu;
1557
1558        /*
1559         * cache last used pipe for splice
1560         */
1561        struct pipe_inode_info *splice_pipe;
1562#ifdef  CONFIG_TASK_DELAY_ACCT
1563        struct task_delay_info *delays;
1564#endif
1565#ifdef CONFIG_FAULT_INJECTION
1566        int make_it_fail;
1567#endif
1568        /*
1569         * when (nr_dirtied >= nr_dirtied_pause), it's time to call
1570         * balance_dirty_pages() for some dirty throttling pause
1571         */
1572        int nr_dirtied;
1573        int nr_dirtied_pause;
1574        unsigned long dirty_paused_when; /* start of a write-and-pause period */
1575
1576#ifdef CONFIG_LATENCYTOP
1577        int latency_record_count;
1578        struct latency_record latency_record[LT_SAVECOUNT];
1579#endif
1580        /*
1581         * time slack values; these are used to round up poll() and
1582         * select() etc timeout values. These are in nanoseconds.
1583         */
1584        unsigned long timer_slack_ns;
1585        unsigned long default_timer_slack_ns;
1586
1587        struct list_head        *scm_work_list;
1588#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1589        /* Index of current stored address in ret_stack */
1590        int curr_ret_stack;
1591        /* Stack of return addresses for return function tracing */
1592        struct ftrace_ret_stack *ret_stack;
1593        /* time stamp for last schedule */
1594        unsigned long long ftrace_timestamp;
1595        /*
1596         * Number of functions that haven't been traced
1597         * because of depth overrun.
1598         */
1599        atomic_t trace_overrun;
1600        /* Pause for the tracing */
1601        atomic_t tracing_graph_pause;
1602#endif
1603#ifdef CONFIG_TRACING
1604        /* state flags for use by tracers */
1605        unsigned long trace;
1606        /* bitmask and counter of trace recursion */
1607        unsigned long trace_recursion;
1608#endif /* CONFIG_TRACING */
1609#ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */
1610        struct memcg_batch_info {
1611                int do_batch;   /* incremented when batch uncharge started */
1612                struct mem_cgroup *memcg; /* target memcg of uncharge */
1613                unsigned long nr_pages; /* uncharged usage */
1614                unsigned long memsw_nr_pages; /* uncharged mem+swap usage */
1615        } memcg_batch;
1616#endif
1617#ifdef CONFIG_HAVE_HW_BREAKPOINT
1618        atomic_t ptrace_bp_refcnt;
1619#endif
1620};
1621
1622/* Future-safe accessor for struct task_struct's cpus_allowed. */
1623#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
1624
1625/*
1626 * Priority of a process goes from 0..MAX_PRIO-1, valid RT
1627 * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
1628 * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
1629 * values are inverted: lower p->prio value means higher priority.
1630 *
1631 * The MAX_USER_RT_PRIO value allows the actual maximum
1632 * RT priority to be separate from the value exported to
1633 * user-space.  This allows kernel threads to set their
1634 * priority to a value higher than any user task. Note:
1635 * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
1636 */
1637
1638#define MAX_USER_RT_PRIO        100
1639#define MAX_RT_PRIO             MAX_USER_RT_PRIO
1640
1641#define MAX_PRIO                (MAX_RT_PRIO + 40)
1642#define DEFAULT_PRIO            (MAX_RT_PRIO + 20)
1643
1644static inline int rt_prio(int prio)
1645{
1646        if (unlikely(prio < MAX_RT_PRIO))
1647                return 1;
1648        return 0;
1649}
1650
1651static inline int rt_task(struct task_struct *p)
1652{
1653        return rt_prio(p->prio);
1654}
1655
1656static inline struct pid *task_pid(struct task_struct *task)
1657{
1658        return task->pids[PIDTYPE_PID].pid;
1659}
1660
1661static inline struct pid *task_tgid(struct task_struct *task)
1662{
1663        return task->group_leader->pids[PIDTYPE_PID].pid;
1664}
1665
1666/*
1667 * Without tasklist or rcu lock it is not safe to dereference
1668 * the result of task_pgrp/task_session even if task == current,
1669 * we can race with another thread doing sys_setsid/sys_setpgid.
1670 */
1671static inline struct pid *task_pgrp(struct task_struct *task)
1672{
1673        return task->group_leader->pids[PIDTYPE_PGID].pid;
1674}
1675
1676static inline struct pid *task_session(struct task_struct *task)
1677{
1678        return task->group_leader->pids[PIDTYPE_SID].pid;
1679}
1680
1681struct pid_namespace;
1682
1683/*
1684 * the helpers to get the task's different pids as they are seen
1685 * from various namespaces
1686 *
1687 * task_xid_nr()     : global id, i.e. the id seen from the init namespace;
1688 * task_xid_vnr()    : virtual id, i.e. the id seen from the pid namespace of
1689 *                     current.
1690 * task_xid_nr_ns()  : id seen from the ns specified;
1691 *
1692 * set_task_vxid()   : assigns a virtual id to a task;
1693 *
1694 * see also pid_nr() etc in include/linux/pid.h
1695 */
1696pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
1697                        struct pid_namespace *ns);
1698
1699static inline pid_t task_pid_nr(struct task_struct *tsk)
1700{
1701        return tsk->pid;
1702}
1703
1704static inline pid_t task_pid_nr_ns(struct task_struct *tsk,
1705                                        struct pid_namespace *ns)
1706{
1707        return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1708}
1709
1710static inline pid_t task_pid_vnr(struct task_struct *tsk)
1711{
1712        return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1713}
1714
1715
1716static inline pid_t task_tgid_nr(struct task_struct *tsk)
1717{
1718        return tsk->tgid;
1719}
1720
1721pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);
1722
1723static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1724{
1725        return pid_vnr(task_tgid(tsk));
1726}
1727
1728
1729static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,
1730                                        struct pid_namespace *ns)
1731{
1732        return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1733}
1734
1735static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1736{
1737        return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1738}
1739
1740
1741static inline pid_t task_session_nr_ns(struct task_struct *tsk,
1742                                        struct pid_namespace *ns)
1743{
1744        return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1745}
1746
1747static inline pid_t task_session_vnr(struct task_struct *tsk)
1748{
1749        return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1750}
1751
1752/* obsolete, do not use */
1753static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1754{
1755        return task_pgrp_nr_ns(tsk, &init_pid_ns);
1756}
1757
1758/**
1759 * pid_alive - check that a task structure is not stale
1760 * @p: Task structure to be checked.
1761 *
1762 * Test if a process is not yet dead (at most zombie state)
1763 * If pid_alive fails, then pointers within the task structure
1764 * can be stale and must not be dereferenced.
1765 */
1766static inline int pid_alive(struct task_struct *p)
1767{
1768        return p->pids[PIDTYPE_PID].pid != NULL;
1769}
1770
1771/**
1772 * is_global_init - check if a task structure is init
1773 * @tsk: Task structure to be checked.
1774 *
1775 * Check if a task structure is the first user space task the kernel created.
1776 */
1777static inline int is_global_init(struct task_struct *tsk)
1778{
1779        return tsk->pid == 1;
1780}
1781
1782/*
1783 * is_container_init:
1784 * check whether in the task is init in its own pid namespace.
1785 */
1786extern int is_container_init(struct task_struct *tsk);
1787
1788extern struct pid *cad_pid;
1789
1790extern void free_task(struct task_struct *tsk);
1791#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
1792
1793extern void __put_task_struct(struct task_struct *t);
1794
1795static inline void put_task_struct(struct task_struct *t)
1796{
1797        if (atomic_dec_and_test(&t->usage))
1798                __put_task_struct(t);
1799}
1800
1801extern void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
1802extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
1803
1804/*
1805 * Per process flags
1806 */
1807#define PF_EXITING      0x00000004      /* getting shut down */
1808#define PF_EXITPIDONE   0x00000008      /* pi exit done on shut down */
1809#define PF_VCPU         0x00000010      /* I'm a virtual CPU */
1810#define PF_WQ_WORKER    0x00000020      /* I'm a workqueue worker */
1811#define PF_FORKNOEXEC   0x00000040      /* forked but didn't exec */
1812#define PF_MCE_PROCESS  0x00000080      /* process policy on mce errors */
1813#define PF_SUPERPRIV    0x00000100      /* used super-user privileges */
1814#define PF_DUMPCORE     0x00000200      /* dumped core */
1815#define PF_SIGNALED     0x00000400      /* killed by a signal */
1816#define PF_MEMALLOC     0x00000800      /* Allocating memory */
1817#define PF_NPROC_EXCEEDED 0x00001000    /* set_user noticed that RLIMIT_NPROC was exceeded */
1818#define PF_USED_MATH    0x00002000      /* if unset the fpu must be initialized before use */
1819#define PF_NOFREEZE     0x00008000      /* this thread should not be frozen */
1820#define PF_FROZEN       0x00010000      /* frozen for system suspend */
1821#define PF_FSTRANS      0x00020000      /* inside a filesystem transaction */
1822#define PF_KSWAPD       0x00040000      /* I am kswapd */
1823#define PF_LESS_THROTTLE 0x00100000     /* Throttle me less: I clean memory */
1824#define PF_KTHREAD      0x00200000      /* I am a kernel thread */
1825#define PF_RANDOMIZE    0x00400000      /* randomize virtual address space */
1826#define PF_SWAPWRITE    0x00800000      /* Allowed to write to swap */
1827#define PF_SPREAD_PAGE  0x01000000      /* Spread page cache over cpuset */
1828#define PF_SPREAD_SLAB  0x02000000      /* Spread some slab caches over cpuset */
1829#define PF_THREAD_BOUND 0x04000000      /* Thread bound to specific cpu */
1830#define PF_MCE_EARLY    0x08000000      /* Early kill for mce process policy */
1831#define PF_MEMPOLICY    0x10000000      /* Non-default NUMA mempolicy */
1832#define PF_MUTEX_TESTER 0x20000000      /* Thread belongs to the rt mutex tester */
1833#define PF_FREEZER_SKIP 0x40000000      /* Freezer should not count it as freezable */
1834
1835/*
1836 * Only the _current_ task can read/write to tsk->flags, but other
1837 * tasks can access tsk->flags in readonly mode for example
1838 * with tsk_used_math (like during threaded core dumping).
1839 * There is however an exception to this rule during ptrace
1840 * or during fork: the ptracer task is allowed to write to the
1841 * child->flags of its traced child (same goes for fork, the parent
1842 * can write to the child->flags), because we're guaranteed the
1843 * child is not running and in turn not changing child->flags
1844 * at the same time the parent does it.
1845 */
1846#define clear_stopped_child_used_math(child) do { (child)->flags &= ~PF_USED_MATH; } while (0)
1847#define set_stopped_child_used_math(child) do { (child)->flags |= PF_USED_MATH; } while (0)
1848#define clear_used_math() clear_stopped_child_used_math(current)
1849#define set_used_math() set_stopped_child_used_math(current)
1850#define conditional_stopped_child_used_math(condition, child) \
1851        do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1852#define conditional_used_math(condition) \
1853        conditional_stopped_child_used_math(condition, current)
1854#define copy_to_stopped_child_used_math(child) \
1855        do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1856/* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1857#define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
1858#define used_math() tsk_used_math(current)
1859
1860/*
1861 * task->jobctl flags
1862 */
1863#define JOBCTL_STOP_SIGMASK     0xffff  /* signr of the last group stop */
1864
1865#define JOBCTL_STOP_DEQUEUED_BIT 16     /* stop signal dequeued */
1866#define JOBCTL_STOP_PENDING_BIT 17      /* task should stop for group stop */
1867#define JOBCTL_STOP_CONSUME_BIT 18      /* consume group stop count */
1868#define JOBCTL_TRAP_STOP_BIT    19      /* trap for STOP */
1869#define JOBCTL_TRAP_NOTIFY_BIT  20      /* trap for NOTIFY */
1870#define JOBCTL_TRAPPING_BIT     21      /* switching to TRACED */
1871#define JOBCTL_LISTENING_BIT    22      /* ptracer is listening for events */
1872
1873#define JOBCTL_STOP_DEQUEUED    (1 << JOBCTL_STOP_DEQUEUED_BIT)
1874#define JOBCTL_STOP_PENDING     (1 << JOBCTL_STOP_PENDING_BIT)
1875#define JOBCTL_STOP_CONSUME     (1 << JOBCTL_STOP_CONSUME_BIT)
1876#define JOBCTL_TRAP_STOP        (1 << JOBCTL_TRAP_STOP_BIT)
1877#define JOBCTL_TRAP_NOTIFY      (1 << JOBCTL_TRAP_NOTIFY_BIT)
1878#define JOBCTL_TRAPPING         (1 << JOBCTL_TRAPPING_BIT)
1879#define JOBCTL_LISTENING        (1 << JOBCTL_LISTENING_BIT)
1880
1881#define JOBCTL_TRAP_MASK        (JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY)
1882#define JOBCTL_PENDING_MASK     (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK)
1883
1884extern bool task_set_jobctl_pending(struct task_struct *task,
1885                                    unsigned int mask);
1886extern void task_clear_jobctl_trapping(struct task_struct *task);
1887extern void task_clear_jobctl_pending(struct task_struct *task,
1888                                      unsigned int mask);
1889
1890#ifdef CONFIG_PREEMPT_RCU
1891
1892#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
1893#define RCU_READ_UNLOCK_NEED_QS (1 << 1) /* RCU core needs CPU response. */
1894
1895static inline void rcu_copy_process(struct task_struct *p)
1896{
1897        p->rcu_read_lock_nesting = 0;
1898        p->rcu_read_unlock_special = 0;
1899#ifdef CONFIG_TREE_PREEMPT_RCU
1900        p->rcu_blocked_node = NULL;
1901#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
1902#ifdef CONFIG_RCU_BOOST
1903        p->rcu_boost_mutex = NULL;
1904#endif /* #ifdef CONFIG_RCU_BOOST */
1905        INIT_LIST_HEAD(&p->rcu_node_entry);
1906}
1907
1908#else
1909
1910static inline void rcu_copy_process(struct task_struct *p)
1911{
1912}
1913
1914#endif
1915
1916#ifdef CONFIG_SMP
1917extern void do_set_cpus_allowed(struct task_struct *p,
1918                               const struct cpumask *new_mask);
1919
1920extern int set_cpus_allowed_ptr(struct task_struct *p,
1921                                const struct cpumask *new_mask);
1922#else
1923static inline void do_set_cpus_allowed(struct task_struct *p,
1924                                      const struct cpumask *new_mask)
1925{
1926}
1927static inline int set_cpus_allowed_ptr(struct task_struct *p,
1928                                       const struct cpumask *new_mask)
1929{
1930        if (!cpumask_test_cpu(0, new_mask))
1931                return -EINVAL;
1932        return 0;
1933}
1934#endif
1935
1936#ifndef CONFIG_CPUMASK_OFFSTACK
1937static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
1938{
1939        return set_cpus_allowed_ptr(p, &new_mask);
1940}
1941#endif
1942
1943/*
1944 * Do not use outside of architecture code which knows its limitations.
1945 *
1946 * sched_clock() has no promise of monotonicity or bounded drift between
1947 * CPUs, use (which you should not) requires disabling IRQs.
1948 *
1949 * Please use one of the three interfaces below.
1950 */
1951extern unsigned long long notrace sched_clock(void);
1952/*
1953 * See the comment in kernel/sched_clock.c
1954 */
1955extern u64 cpu_clock(int cpu);
1956extern u64 local_clock(void);
1957extern u64 sched_clock_cpu(int cpu);
1958
1959
1960extern void sched_clock_init(void);
1961
1962#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
1963static inline void sched_clock_tick(void)
1964{
1965}
1966
1967static inline void sched_clock_idle_sleep_event(void)
1968{
1969}
1970
1971static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
1972{
1973}
1974#else
1975/*
1976 * Architectures can set this to 1 if they have specified
1977 * CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
1978 * but then during bootup it turns out that sched_clock()
1979 * is reliable after all:
1980 */
1981extern int sched_clock_stable;
1982
1983extern void sched_clock_tick(void);
1984extern void sched_clock_idle_sleep_event(void);
1985extern void sched_clock_idle_wakeup_event(u64 delta_ns);
1986#endif
1987
1988#ifdef CONFIG_IRQ_TIME_ACCOUNTING
1989/*
1990 * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
1991 * The reason for this explicit opt-in is not to have perf penalty with
1992 * slow sched_clocks.
1993 */
1994extern void enable_sched_clock_irqtime(void);
1995extern void disable_sched_clock_irqtime(void);
1996#else
1997static inline void enable_sched_clock_irqtime(void) {}
1998static inline void disable_sched_clock_irqtime(void) {}
1999#endif
2000
2001extern unsigned long long
2002task_sched_runtime(struct task_struct *task);
2003
2004/* sched_exec is called by processes performing an exec */
2005#ifdef CONFIG_SMP
2006extern void sched_exec(void);
2007#else
2008#define sched_exec()   {}
2009#endif
2010
2011extern void sched_clock_idle_sleep_event(void);
2012extern void sched_clock_idle_wakeup_event(u64 delta_ns);
2013
2014#ifdef CONFIG_HOTPLUG_CPU
2015extern void idle_task_exit(void);
2016#else
2017static inline void idle_task_exit(void) {}
2018#endif
2019
2020#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
2021extern void wake_up_idle_cpu(int cpu);
2022#else
2023static inline void wake_up_idle_cpu(int cpu) { }
2024#endif
2025
2026extern unsigned int sysctl_sched_latency;
2027extern unsigned int sysctl_sched_min_granularity;
2028extern unsigned int sysctl_sched_wakeup_granularity;
2029extern unsigned int sysctl_sched_child_runs_first;
2030
2031enum sched_tunable_scaling {
2032        SCHED_TUNABLESCALING_NONE,
2033        SCHED_TUNABLESCALING_LOG,
2034        SCHED_TUNABLESCALING_LINEAR,
2035        SCHED_TUNABLESCALING_END,
2036};
2037extern enum sched_tunable_scaling sysctl_sched_tunable_scaling;
2038
2039#ifdef CONFIG_SCHED_DEBUG
2040extern unsigned int sysctl_sched_migration_cost;
2041extern unsigned int sysctl_sched_nr_migrate;
2042extern unsigned int sysctl_sched_time_avg;
2043extern unsigned int sysctl_timer_migration;
2044extern unsigned int sysctl_sched_shares_window;
2045
2046int sched_proc_update_handler(struct ctl_table *table, int write,
2047                void __user *buffer, size_t *length,
2048                loff_t *ppos);
2049#endif
2050#ifdef CONFIG_SCHED_DEBUG
2051static inline unsigned int get_sysctl_timer_migration(void)
2052{
2053        return sysctl_timer_migration;
2054}
2055#else
2056static inline unsigned int get_sysctl_timer_migration(void)
2057{
2058        return 1;
2059}
2060#endif
2061extern unsigned int sysctl_sched_rt_period;
2062extern int sysctl_sched_rt_runtime;
2063
2064int sched_rt_handler(struct ctl_table *table, int write,
2065                void __user *buffer, size_t *lenp,
2066                loff_t *ppos);
2067
2068#ifdef CONFIG_SCHED_AUTOGROUP
2069extern unsigned int sysctl_sched_autogroup_enabled;
2070
2071extern void sched_autogroup_create_attach(struct task_struct *p);
2072extern void sched_autogroup_detach(struct task_struct *p);
2073extern void sched_autogroup_fork(struct signal_struct *sig);
2074extern void sched_autogroup_exit(struct signal_struct *sig);
2075#ifdef CONFIG_PROC_FS
2076extern void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m);
2077extern int proc_sched_autogroup_set_nice(struct task_struct *p, int nice);
2078#endif
2079#else
2080static inline void sched_autogroup_create_attach(struct task_struct *p) { }
2081static inline void sched_autogroup_detach(struct task_struct *p) { }
2082static inline void sched_autogroup_fork(struct signal_struct *sig) { }
2083static inline void sched_autogroup_exit(struct signal_struct *sig) { }
2084#endif
2085
2086#ifdef CONFIG_CFS_BANDWIDTH
2087extern unsigned int sysctl_sched_cfs_bandwidth_slice;
2088#endif
2089
2090#ifdef CONFIG_RT_MUTEXES
2091extern int rt_mutex_getprio(struct task_struct *p);
2092extern void rt_mutex_setprio(struct task_struct *p, int prio);
2093extern void rt_mutex_adjust_pi(struct task_struct *p);
2094static inline bool tsk_is_pi_blocked(struct task_struct *tsk)
2095{
2096        return tsk->pi_blocked_on != NULL;
2097}
2098#else
2099static inline int rt_mutex_getprio(struct task_struct *p)
2100{
2101        return p->normal_prio;
2102}
2103# define rt_mutex_adjust_pi(p)          do { } while (0)
2104static inline bool tsk_is_pi_blocked(struct task_struct *tsk)
2105{
2106        return false;
2107}
2108#endif
2109
2110extern bool yield_to(struct task_struct *p, bool preempt);
2111extern void set_user_nice(struct task_struct *p, long nice);
2112extern int task_prio(const struct task_struct *p);
2113extern int task_nice(const struct task_struct *p);
2114extern int can_nice(const struct task_struct *p, const int nice);
2115extern int task_curr(const struct task_struct *p);
2116extern int idle_cpu(int cpu);
2117extern int sched_setscheduler(struct task_struct *, int,
2118                              const struct sched_param *);
2119extern int sched_setscheduler_nocheck(struct task_struct *, int,
2120                                      const struct sched_param *);
2121extern struct task_struct *idle_task(int cpu);
2122/**
2123 * is_idle_task - is the specified task an idle task?
2124 * @p: the task in question.
2125 */
2126static inline bool is_idle_task(const struct task_struct *p)
2127{
2128        return p->pid == 0;
2129}
2130extern struct task_struct *curr_task(int cpu);
2131extern void set_curr_task(int cpu, struct task_struct *p);
2132
2133void yield(void);
2134
2135/*
2136 * The default (Linux) execution domain.
2137 */
2138extern struct exec_domain       default_exec_domain;
2139
2140union thread_union {
2141        struct thread_info thread_info;
2142        unsigned long stack[THREAD_SIZE/sizeof(long)];
2143};
2144
2145#ifndef __HAVE_ARCH_KSTACK_END
2146static inline int kstack_end(void *addr)
2147{
2148        /* Reliable end of stack detection:
2149         * Some APM bios versions misalign the stack
2150         */
2151        return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*)));
2152}
2153#endif
2154
2155extern union thread_union init_thread_union;
2156extern struct task_struct init_task;
2157
2158extern struct   mm_struct init_mm;
2159
2160extern struct pid_namespace init_pid_ns;
2161
2162/*
2163 * find a task by one of its numerical ids
2164 *
2165 * find_task_by_pid_ns():
2166 *      finds a task by its pid in the specified namespace
2167 * find_task_by_vpid():
2168 *      finds a task by its virtual pid
2169 *
2170 * see also find_vpid() etc in include/linux/pid.h
2171 */
2172
2173extern struct task_struct *find_task_by_vpid(pid_t nr);
2174extern struct task_struct *find_task_by_pid_ns(pid_t nr,
2175                struct pid_namespace *ns);
2176
2177extern void __set_special_pids(struct pid *pid);
2178
2179/* per-UID process charging. */
2180extern struct user_struct * alloc_uid(struct user_namespace *, uid_t);
2181static inline struct user_struct *get_uid(struct user_struct *u)
2182{
2183        atomic_inc(&u->__count);
2184        return u;
2185}
2186extern void free_uid(struct user_struct *);
2187extern void release_uids(struct user_namespace *ns);
2188
2189#include <asm/current.h>
2190
2191extern void xtime_update(unsigned long ticks);
2192
2193extern int wake_up_state(struct task_struct *tsk, unsigned int state);
2194extern int wake_up_process(struct task_struct *tsk);
2195extern void wake_up_new_task(struct task_struct *tsk);
2196#ifdef CONFIG_SMP
2197 extern void kick_process(struct task_struct *tsk);
2198#else
2199 static inline void kick_process(struct task_struct *tsk) { }
2200#endif
2201extern void sched_fork(struct task_struct *p);
2202extern void sched_dead(struct task_struct *p);
2203
2204extern void proc_caches_init(void);
2205extern void flush_signals(struct task_struct *);
2206extern void __flush_signals(struct task_struct *);
2207extern void ignore_signals(struct task_struct *);
2208extern void flush_signal_handlers(struct task_struct *, int force_default);
2209extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
2210
2211static inline int dequeue_signal_lock(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
2212{
2213        unsigned long flags;
2214        int ret;
2215
2216        spin_lock_irqsave(&tsk->sighand->siglock, flags);
2217        ret = dequeue_signal(tsk, mask, info);
2218        spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2219
2220        return ret;
2221}
2222
2223extern void block_all_signals(int (*notifier)(void *priv), void *priv,
2224                              sigset_t *mask);
2225extern void unblock_all_signals(void);
2226extern void release_task(struct task_struct * p);
2227extern int send_sig_info(int, struct siginfo *, struct task_struct *);
2228extern int force_sigsegv(int, struct task_struct *);
2229extern int force_sig_info(int, struct siginfo *, struct task_struct *);
2230extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
2231extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
2232extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *,
2233                                const struct cred *, u32);
2234extern int kill_pgrp(struct pid *pid, int sig, int priv);
2235extern int kill_pid(struct pid *pid, int sig, int priv);
2236extern int kill_proc_info(int, struct siginfo *, pid_t);
2237extern __must_check bool do_notify_parent(struct task_struct *, int);
2238extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
2239extern void force_sig(int, struct task_struct *);
2240extern int send_sig(int, struct task_struct *, int);
2241extern int zap_other_threads(struct task_struct *p);
2242extern struct sigqueue *sigqueue_alloc(void);
2243extern void sigqueue_free(struct sigqueue *);
2244extern int send_sigqueue(struct sigqueue *,  struct task_struct *, int group);
2245extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
2246extern int do_sigaltstack(const stack_t __user *, stack_t __user *, unsigned long);
2247
2248static inline int kill_cad_pid(int sig, int priv)
2249{
2250        return kill_pid(cad_pid, sig, priv);
2251}
2252
2253/* These can be the second arg to send_sig_info/send_group_sig_info.  */
2254#define SEND_SIG_NOINFO ((struct siginfo *) 0)
2255#define SEND_SIG_PRIV   ((struct siginfo *) 1)
2256#define SEND_SIG_FORCED ((struct siginfo *) 2)
2257
2258/*
2259 * True if we are on the alternate signal stack.
2260 */
2261static inline int on_sig_stack(unsigned long sp)
2262{
2263#ifdef CONFIG_STACK_GROWSUP
2264        return sp >= current->sas_ss_sp &&
2265                sp - current->sas_ss_sp < current->sas_ss_size;
2266#else
2267        return sp > current->sas_ss_sp &&
2268                sp - current->sas_ss_sp <= current->sas_ss_size;
2269#endif
2270}
2271
2272static inline int sas_ss_flags(unsigned long sp)
2273{
2274        return (current->sas_ss_size == 0 ? SS_DISABLE
2275                : on_sig_stack(sp) ? SS_ONSTACK : 0);
2276}
2277
2278/*
2279 * Routines for handling mm_structs
2280 */
2281extern struct mm_struct * mm_alloc(void);
2282
2283/* mmdrop drops the mm and the page tables */
2284extern void __mmdrop(struct mm_struct *);
2285static inline void mmdrop(struct mm_struct * mm)
2286{
2287        if (unlikely(atomic_dec_and_test(&mm->mm_count)))
2288                __mmdrop(mm);
2289}
2290
2291/* mmput gets rid of the mappings and all user-space */
2292extern void mmput(struct mm_struct *);
2293/* Grab a reference to a task's mm, if it is not already going away */
2294extern struct mm_struct *get_task_mm(struct task_struct *task);
2295/*
2296 * Grab a reference to a task's mm, if it is not already going away
2297 * and ptrace_may_access with the mode parameter passed to it
2298 * succeeds.
2299 */
2300extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode);
2301/* Remove the current tasks stale references to the old mm_struct */
2302extern void mm_release(struct task_struct *, struct mm_struct *);
2303/* Allocate a new mm structure and copy contents from tsk->mm */
2304extern struct mm_struct *dup_mm(struct task_struct *tsk);
2305
2306extern int copy_thread(unsigned long, unsigned long, unsigned long,
2307                        struct task_struct *, struct pt_regs *);
2308extern void flush_thread(void);
2309extern void exit_thread(void);
2310
2311extern void exit_files(struct task_struct *);
2312extern void __cleanup_sighand(struct sighand_struct *);
2313
2314extern void exit_itimers(struct signal_struct *);
2315extern void flush_itimer_signals(void);
2316
2317extern void do_group_exit(int);
2318
2319extern void daemonize(const char *, ...);
2320extern int allow_signal(int);
2321extern int disallow_signal(int);
2322
2323extern int do_execve(const char *,
2324                     const char __user * const __user *,
2325                     const char __user * const __user *, struct pt_regs *);
2326extern long do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *);
2327struct task_struct *fork_idle(int);
2328
2329extern void set_task_comm(struct task_struct *tsk, char *from);
2330extern char *get_task_comm(char *to, struct task_struct *tsk);
2331
2332#ifdef CONFIG_SMP
2333void scheduler_ipi(void);
2334extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
2335#else
2336static inline void scheduler_ipi(void) { }
2337static inline unsigned long wait_task_inactive(struct task_struct *p,
2338                                               long match_state)
2339{
2340        return 1;
2341}
2342#endif
2343
2344#define next_task(p) \
2345        list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
2346
2347#define for_each_process(p) \
2348        for (p = &init_task ; (p = next_task(p)) != &init_task ; )
2349
2350extern bool current_is_single_threaded(void);
2351
2352/*
2353 * Careful: do_each_thread/while_each_thread is a double loop so
2354 *          'break' will not work as expected - use goto instead.
2355 */
2356#define do_each_thread(g, t) \
2357        for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
2358
2359#define while_each_thread(g, t) \
2360        while ((t = next_thread(t)) != g)
2361
2362static inline int get_nr_threads(struct task_struct *tsk)
2363{
2364        return tsk->signal->nr_threads;
2365}
2366
2367static inline bool thread_group_leader(struct task_struct *p)
2368{
2369        return p->exit_signal >= 0;
2370}
2371
2372/* Do to the insanities of de_thread it is possible for a process
2373 * to have the pid of the thread group leader without actually being
2374 * the thread group leader.  For iteration through the pids in proc
2375 * all we care about is that we have a task with the appropriate
2376 * pid, we don't actually care if we have the right task.
2377 */
2378static inline int has_group_leader_pid(struct task_struct *p)
2379{
2380        return p->pid == p->tgid;
2381}
2382
2383static inline
2384int same_thread_group(struct task_struct *p1, struct task_struct *p2)
2385{
2386        return p1->tgid == p2->tgid;
2387}
2388
2389static inline struct task_struct *next_thread(const struct task_struct *p)
2390{
2391        return list_entry_rcu(p->thread_group.next,
2392                              struct task_struct, thread_group);
2393}
2394
2395static inline int thread_group_empty(struct task_struct *p)
2396{
2397        return list_empty(&p->thread_group);
2398}
2399
2400#define delay_group_leader(p) \
2401                (thread_group_leader(p) && !thread_group_empty(p))
2402
2403/*
2404 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
2405 * subscriptions and synchronises with wait4().  Also used in procfs.  Also
2406 * pins the final release of task.io_context.  Also protects ->cpuset and
2407 * ->cgroup.subsys[]. And ->vfork_done.
2408 *
2409 * Nests both inside and outside of read_lock(&tasklist_lock).
2410 * It must not be nested with write_lock_irq(&tasklist_lock),
2411 * neither inside nor outside.
2412 */
2413static inline void task_lock(struct task_struct *p)
2414{
2415        spin_lock(&p->alloc_lock);
2416}
2417
2418static inline void task_unlock(struct task_struct *p)
2419{
2420        spin_unlock(&p->alloc_lock);
2421}
2422
2423extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
2424                                                        unsigned long *flags);
2425
2426static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
2427                                                       unsigned long *flags)
2428{
2429        struct sighand_struct *ret;
2430
2431        ret = __lock_task_sighand(tsk, flags);
2432        (void)__cond_lock(&tsk->sighand->siglock, ret);
2433        return ret;
2434}
2435
2436static inline void unlock_task_sighand(struct task_struct *tsk,
2437                                                unsigned long *flags)
2438{
2439        spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
2440}
2441
2442#ifdef CONFIG_CGROUPS
2443static inline void threadgroup_change_begin(struct task_struct *tsk)
2444{
2445        down_read(&tsk->signal->group_rwsem);
2446}
2447static inline void threadgroup_change_end(struct task_struct *tsk)
2448{
2449        up_read(&tsk->signal->group_rwsem);
2450}
2451
2452/**
2453 * threadgroup_lock - lock threadgroup
2454 * @tsk: member task of the threadgroup to lock
2455 *
2456 * Lock the threadgroup @tsk belongs to.  No new task is allowed to enter
2457 * and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
2458 * perform exec.  This is useful for cases where the threadgroup needs to
2459 * stay stable across blockable operations.
2460 *
2461 * fork and exit paths explicitly call threadgroup_change_{begin|end}() for
2462 * synchronization.  While held, no new task will be added to threadgroup
2463 * and no existing live task will have its PF_EXITING set.
2464 *
2465 * During exec, a task goes and puts its thread group through unusual
2466 * changes.  After de-threading, exclusive access is assumed to resources
2467 * which are usually shared by tasks in the same group - e.g. sighand may
2468 * be replaced with a new one.  Also, the exec'ing task takes over group
2469 * leader role including its pid.  Exclude these changes while locked by
2470 * grabbing cred_guard_mutex which is used to synchronize exec path.
2471 */
2472static inline void threadgroup_lock(struct task_struct *tsk)
2473{
2474        /*
2475         * exec uses exit for de-threading nesting group_rwsem inside
2476         * cred_guard_mutex. Grab cred_guard_mutex first.
2477         */
2478        mutex_lock(&tsk->signal->cred_guard_mutex);
2479        down_write(&tsk->signal->group_rwsem);
2480}
2481
2482/**
2483 * threadgroup_unlock - unlock threadgroup
2484 * @tsk: member task of the threadgroup to unlock
2485 *
2486 * Reverse threadgroup_lock().
2487 */
2488static inline void threadgroup_unlock(struct task_struct *tsk)
2489{
2490        up_write(&tsk->signal->group_rwsem);
2491        mutex_unlock(&tsk->signal->cred_guard_mutex);
2492}
2493#else
2494static inline void threadgroup_change_begin(struct task_struct *tsk) {}
2495static inline void threadgroup_change_end(struct task_struct *tsk) {}
2496static inline void threadgroup_lock(struct task_struct *tsk) {}
2497static inline void threadgroup_unlock(struct task_struct *tsk) {}
2498#endif
2499
2500#ifndef __HAVE_THREAD_FUNCTIONS
2501
2502#define task_thread_info(task)  ((struct thread_info *)(task)->stack)
2503#define task_stack_page(task)   ((task)->stack)
2504
2505static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)
2506{
2507        *task_thread_info(p) = *task_thread_info(org);
2508        task_thread_info(p)->task = p;
2509}
2510
2511static inline unsigned long *end_of_stack(struct task_struct *p)
2512{
2513        return (unsigned long *)(task_thread_info(p) + 1);
2514}
2515
2516#endif
2517
2518static inline int object_is_on_stack(void *obj)
2519{
2520        void *stack = task_stack_page(current);
2521
2522        return (obj >= stack) && (obj < (stack + THREAD_SIZE));
2523}
2524
2525extern void thread_info_cache_init(void);
2526
2527#ifdef CONFIG_DEBUG_STACK_USAGE
2528static inline unsigned long stack_not_used(struct task_struct *p)
2529{
2530        unsigned long *n = end_of_stack(p);
2531
2532        do {    /* Skip over canary */
2533                n++;
2534        } while (!*n);
2535
2536        return (unsigned long)n - (unsigned long)end_of_stack(p);
2537}
2538#endif
2539
2540/* set thread flags in other task's structures
2541 * - see asm/thread_info.h for TIF_xxxx flags available
2542 */
2543static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
2544{
2545        set_ti_thread_flag(task_thread_info(tsk), flag);
2546}
2547
2548static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2549{
2550        clear_ti_thread_flag(task_thread_info(tsk), flag);
2551}
2552
2553static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
2554{
2555        return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
2556}
2557
2558static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
2559{
2560        return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
2561}
2562
2563static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
2564{
2565        return test_ti_thread_flag(task_thread_info(tsk), flag);
2566}
2567
2568static inline void set_tsk_need_resched(struct task_struct *tsk)
2569{
2570        set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2571}
2572
2573static inline void clear_tsk_need_resched(struct task_struct *tsk)
2574{
2575        clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2576}
2577
2578static inline int test_tsk_need_resched(struct task_struct *tsk)
2579{
2580        return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
2581}
2582
2583static inline int restart_syscall(void)
2584{
2585        set_tsk_thread_flag(current, TIF_SIGPENDING);
2586        return -ERESTARTNOINTR;
2587}
2588
2589static inline int signal_pending(struct task_struct *p)
2590{
2591        return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
2592}
2593
2594static inline int __fatal_signal_pending(struct task_struct *p)
2595{
2596        return unlikely(sigismember(&p->pending.signal, SIGKILL));
2597}
2598
2599static inline int fatal_signal_pending(struct task_struct *p)
2600{
2601        return signal_pending(p) && __fatal_signal_pending(p);
2602}
2603
2604static inline int signal_pending_state(long state, struct task_struct *p)
2605{
2606        if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
2607                return 0;
2608        if (!signal_pending(p))
2609                return 0;
2610
2611        return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
2612}
2613
2614static inline int need_resched(void)
2615{
2616        return unlikely(test_thread_flag(TIF_NEED_RESCHED));
2617}
2618
2619/*
2620 * cond_resched() and cond_resched_lock(): latency reduction via
2621 * explicit rescheduling in places that are safe. The return
2622 * value indicates whether a reschedule was done in fact.
2623 * cond_resched_lock() will drop the spinlock before scheduling,
2624 * cond_resched_softirq() will enable bhs before scheduling.
2625 */
2626extern int _cond_resched(void);
2627
2628#define cond_resched() ({                       \
2629        __might_sleep(__FILE__, __LINE__, 0);   \
2630        _cond_resched();                        \
2631})
2632
2633extern int __cond_resched_lock(spinlock_t *lock);
2634
2635#ifdef CONFIG_PREEMPT_COUNT
2636#define PREEMPT_LOCK_OFFSET     PREEMPT_OFFSET
2637#else
2638#define PREEMPT_LOCK_OFFSET     0
2639#endif
2640
2641#define cond_resched_lock(lock) ({                              \
2642        __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \
2643        __cond_resched_lock(lock);                              \
2644})
2645
2646extern int __cond_resched_softirq(void);
2647
2648#define cond_resched_softirq() ({                                       \
2649        __might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET);      \
2650        __cond_resched_softirq();                                       \
2651})
2652
2653/*
2654 * Does a critical section need to be broken due to another
2655 * task waiting?: (technically does not depend on CONFIG_PREEMPT,
2656 * but a general need for low latency)
2657 */
2658static inline int spin_needbreak(spinlock_t *lock)
2659{
2660#ifdef CONFIG_PREEMPT
2661        return spin_is_contended(lock);
2662#else
2663        return 0;
2664#endif
2665}
2666
2667/*
2668 * Thread group CPU time accounting.
2669 */
2670void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
2671void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);
2672
2673static inline void thread_group_cputime_init(struct signal_struct *sig)
2674{
2675        raw_spin_lock_init(&sig->cputimer.lock);
2676}
2677
2678/*
2679 * Reevaluate whether the task has signals pending delivery.
2680 * Wake the task if so.
2681 * This is required every time the blocked sigset_t changes.
2682 * callers must hold sighand->siglock.
2683 */
2684extern void recalc_sigpending_and_wake(struct task_struct *t);
2685extern void recalc_sigpending(void);
2686
2687extern void signal_wake_up(struct task_struct *t, int resume_stopped);
2688
2689/*
2690 * Wrappers for p->thread_info->cpu access. No-op on UP.
2691 */
2692#ifdef CONFIG_SMP
2693
2694static inline unsigned int task_cpu(const struct task_struct *p)
2695{
2696        return task_thread_info(p)->cpu;
2697}
2698
2699extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
2700
2701#else
2702
2703static inline unsigned int task_cpu(const struct task_struct *p)
2704{
2705        return 0;
2706}
2707
2708static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
2709{
2710}
2711
2712#endif /* CONFIG_SMP */
2713
2714extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
2715extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
2716
2717extern void normalize_rt_tasks(void);
2718
2719#ifdef CONFIG_CGROUP_SCHED
2720
2721extern struct task_group root_task_group;
2722
2723extern struct task_group *sched_create_group(struct task_group *parent);
2724extern void sched_destroy_group(struct task_group *tg);
2725extern void sched_move_task(struct task_struct *tsk);
2726#ifdef CONFIG_FAIR_GROUP_SCHED
2727extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
2728extern unsigned long sched_group_shares(struct task_group *tg);
2729#endif
2730#ifdef CONFIG_RT_GROUP_SCHED
2731extern int sched_group_set_rt_runtime(struct task_group *tg,
2732                                      long rt_runtime_us);
2733extern long sched_group_rt_runtime(struct task_group *tg);
2734extern int sched_group_set_rt_period(struct task_group *tg,
2735                                      long rt_period_us);
2736extern long sched_group_rt_period(struct task_group *tg);
2737extern int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk);
2738#endif
2739#endif
2740
2741extern int task_can_switch_user(struct user_struct *up,
2742                                        struct task_struct *tsk);
2743
2744#ifdef CONFIG_TASK_XACCT
2745static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
2746{
2747        tsk->ioac.rchar += amt;
2748}
2749
2750static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
2751{
2752        tsk->ioac.wchar += amt;
2753}
2754
2755static inline void inc_syscr(struct task_struct *tsk)
2756{
2757        tsk->ioac.syscr++;
2758}
2759
2760static inline void inc_syscw(struct task_struct *tsk)
2761{
2762        tsk->ioac.syscw++;
2763}
2764#else
2765static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
2766{
2767}
2768
2769static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
2770{
2771}
2772
2773static inline void inc_syscr(struct task_struct *tsk)
2774{
2775}
2776
2777static inline void inc_syscw(struct task_struct *tsk)
2778{
2779}
2780#endif
2781
2782#ifndef TASK_SIZE_OF
2783#define TASK_SIZE_OF(tsk)       TASK_SIZE
2784#endif
2785
2786#ifdef CONFIG_MM_OWNER
2787extern void mm_update_next_owner(struct mm_struct *mm);
2788extern void mm_init_owner(struct mm_struct *mm, struct task_struct *p);
2789#else
2790static inline void mm_update_next_owner(struct mm_struct *mm)
2791{
2792}
2793
2794static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
2795{
2796}
2797#endif /* CONFIG_MM_OWNER */
2798
2799static inline unsigned long task_rlimit(const struct task_struct *tsk,
2800                unsigned int limit)
2801{
2802        return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_cur);
2803}
2804
2805static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
2806                unsigned int limit)
2807{
2808        return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_max);
2809}
2810
2811static inline unsigned long rlimit(unsigned int limit)
2812{
2813        return task_rlimit(current, limit);
2814}
2815
2816static inline unsigned long rlimit_max(unsigned int limit)
2817{
2818        return task_rlimit_max(current, limit);
2819}
2820
2821#endif /* __KERNEL__ */
2822
2823#endif
2824
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