4 #include <uapi/linux/sched.h>
6 #include <linux/sched/prio.h>
8 #include <linux/capability.h>
9 #include <linux/mutex.h>
10 #include <linux/plist.h>
11 #include <linux/mm_types_task.h>
12 #include <asm/ptrace.h>
14 #include <linux/sem.h>
15 #include <linux/shm.h>
16 #include <linux/signal.h>
17 #include <linux/signal_types.h>
18 #include <linux/pid.h>
19 #include <linux/seccomp.h>
20 #include <linux/rculist.h>
21 #include <linux/rtmutex.h>
23 #include <linux/resource.h>
24 #include <linux/hrtimer.h>
25 #include <linux/kcov.h>
26 #include <linux/task_io_accounting.h>
27 #include <linux/latencytop.h>
28 #include <linux/cred.h>
29 #include <linux/gfp.h>
30 #include <linux/topology.h>
31 #include <linux/magic.h>
32 #include <linux/cgroup-defs.h>
34 #include <asm/current.h>
36 /* task_struct member predeclarations: */
39 struct backing_dev_info;
45 struct futex_pi_state;
50 struct perf_event_context;
52 struct pipe_inode_info;
55 struct robust_list_head;
59 struct sighand_struct;
61 struct task_delay_info;
67 * Task state bitmask. NOTE! These bits are also
68 * encoded in fs/proc/array.c: get_task_state().
70 * We have two separate sets of flags: task->state
71 * is about runnability, while task->exit_state are
72 * about the task exiting. Confusing, but this way
73 * modifying one set can't modify the other one by
76 #define TASK_RUNNING 0
77 #define TASK_INTERRUPTIBLE 1
78 #define TASK_UNINTERRUPTIBLE 2
79 #define __TASK_STOPPED 4
80 #define __TASK_TRACED 8
81 /* in tsk->exit_state */
83 #define EXIT_ZOMBIE 32
84 #define EXIT_TRACE (EXIT_ZOMBIE | EXIT_DEAD)
85 /* in tsk->state again */
87 #define TASK_WAKEKILL 128
88 #define TASK_WAKING 256
89 #define TASK_PARKED 512
90 #define TASK_NOLOAD 1024
92 #define TASK_STATE_MAX 4096
94 #define TASK_STATE_TO_CHAR_STR "RSDTtXZxKWPNn"
96 /* Convenience macros for the sake of set_current_state */
97 #define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
98 #define TASK_STOPPED (TASK_WAKEKILL | __TASK_STOPPED)
99 #define TASK_TRACED (TASK_WAKEKILL | __TASK_TRACED)
101 #define TASK_IDLE (TASK_UNINTERRUPTIBLE | TASK_NOLOAD)
103 /* Convenience macros for the sake of wake_up */
104 #define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
105 #define TASK_ALL (TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)
107 /* get_task_state() */
108 #define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \
109 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
110 __TASK_TRACED | EXIT_ZOMBIE | EXIT_DEAD)
112 #define task_is_traced(task) ((task->state & __TASK_TRACED) != 0)
113 #define task_is_stopped(task) ((task->state & __TASK_STOPPED) != 0)
114 #define task_is_stopped_or_traced(task) \
115 ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
116 #define task_contributes_to_load(task) \
117 ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
118 (task->flags & PF_FROZEN) == 0 && \
119 (task->state & TASK_NOLOAD) == 0)
121 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
123 #define __set_current_state(state_value) \
125 current->task_state_change = _THIS_IP_; \
126 current->state = (state_value); \
128 #define set_current_state(state_value) \
130 current->task_state_change = _THIS_IP_; \
131 smp_store_mb(current->state, (state_value)); \
136 * set_current_state() includes a barrier so that the write of current->state
137 * is correctly serialised wrt the caller's subsequent test of whether to
141 * set_current_state(TASK_UNINTERRUPTIBLE);
147 * __set_current_state(TASK_RUNNING);
149 * If the caller does not need such serialisation (because, for instance, the
150 * condition test and condition change and wakeup are under the same lock) then
151 * use __set_current_state().
153 * The above is typically ordered against the wakeup, which does:
155 * need_sleep = false;
156 * wake_up_state(p, TASK_UNINTERRUPTIBLE);
158 * Where wake_up_state() (and all other wakeup primitives) imply enough
159 * barriers to order the store of the variable against wakeup.
161 * Wakeup will do: if (@state & p->state) p->state = TASK_RUNNING, that is,
162 * once it observes the TASK_UNINTERRUPTIBLE store the waking CPU can issue a
163 * TASK_RUNNING store which can collide with __set_current_state(TASK_RUNNING).
165 * This is obviously fine, since they both store the exact same value.
167 * Also see the comments of try_to_wake_up().
169 #define __set_current_state(state_value) \
170 do { current->state = (state_value); } while (0)
171 #define set_current_state(state_value) \
172 smp_store_mb(current->state, (state_value))
176 /* Task command name length */
177 #define TASK_COMM_LEN 16
179 extern void sched_init(void);
180 extern void sched_init_smp(void);
182 extern cpumask_var_t cpu_isolated_map;
184 extern int runqueue_is_locked(int cpu);
186 extern void cpu_init (void);
187 extern void trap_init(void);
188 extern void update_process_times(int user);
189 extern void scheduler_tick(void);
191 #define MAX_SCHEDULE_TIMEOUT LONG_MAX
192 extern signed long schedule_timeout(signed long timeout);
193 extern signed long schedule_timeout_interruptible(signed long timeout);
194 extern signed long schedule_timeout_killable(signed long timeout);
195 extern signed long schedule_timeout_uninterruptible(signed long timeout);
196 extern signed long schedule_timeout_idle(signed long timeout);
197 asmlinkage void schedule(void);
198 extern void schedule_preempt_disabled(void);
200 extern int __must_check io_schedule_prepare(void);
201 extern void io_schedule_finish(int token);
202 extern long io_schedule_timeout(long timeout);
203 extern void io_schedule(void);
206 * struct prev_cputime - snaphsot of system and user cputime
207 * @utime: time spent in user mode
208 * @stime: time spent in system mode
209 * @lock: protects the above two fields
211 * Stores previous user/system time values such that we can guarantee
214 struct prev_cputime {
215 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
223 * struct task_cputime - collected CPU time counts
224 * @utime: time spent in user mode, in nanoseconds
225 * @stime: time spent in kernel mode, in nanoseconds
226 * @sum_exec_runtime: total time spent on the CPU, in nanoseconds
228 * This structure groups together three kinds of CPU time that are tracked for
229 * threads and thread groups. Most things considering CPU time want to group
230 * these counts together and treat all three of them in parallel.
232 struct task_cputime {
235 unsigned long long sum_exec_runtime;
238 /* Alternate field names when used to cache expirations. */
239 #define virt_exp utime
240 #define prof_exp stime
241 #define sched_exp sum_exec_runtime
243 #include <linux/rwsem.h>
245 #ifdef CONFIG_SCHED_INFO
247 /* cumulative counters */
248 unsigned long pcount; /* # of times run on this cpu */
249 unsigned long long run_delay; /* time spent waiting on a runqueue */
252 unsigned long long last_arrival,/* when we last ran on a cpu */
253 last_queued; /* when we were last queued to run */
255 #endif /* CONFIG_SCHED_INFO */
257 static inline int sched_info_on(void)
259 #ifdef CONFIG_SCHEDSTATS
261 #elif defined(CONFIG_TASK_DELAY_ACCT)
262 extern int delayacct_on;
269 #ifdef CONFIG_SCHEDSTATS
270 void force_schedstat_enabled(void);
274 * Integer metrics need fixed point arithmetic, e.g., sched/fair
275 * has a few: load, load_avg, util_avg, freq, and capacity.
277 * We define a basic fixed point arithmetic range, and then formalize
278 * all these metrics based on that basic range.
280 # define SCHED_FIXEDPOINT_SHIFT 10
281 # define SCHED_FIXEDPOINT_SCALE (1L << SCHED_FIXEDPOINT_SHIFT)
283 #ifdef ARCH_HAS_PREFETCH_SWITCH_STACK
284 extern void prefetch_stack(struct task_struct *t);
286 static inline void prefetch_stack(struct task_struct *t) { }
290 unsigned long weight;
295 * The load_avg/util_avg accumulates an infinite geometric series
296 * (see __update_load_avg() in kernel/sched/fair.c).
298 * [load_avg definition]
300 * load_avg = runnable% * scale_load_down(load)
302 * where runnable% is the time ratio that a sched_entity is runnable.
303 * For cfs_rq, it is the aggregated load_avg of all runnable and
304 * blocked sched_entities.
306 * load_avg may also take frequency scaling into account:
308 * load_avg = runnable% * scale_load_down(load) * freq%
310 * where freq% is the CPU frequency normalized to the highest frequency.
312 * [util_avg definition]
314 * util_avg = running% * SCHED_CAPACITY_SCALE
316 * where running% is the time ratio that a sched_entity is running on
317 * a CPU. For cfs_rq, it is the aggregated util_avg of all runnable
318 * and blocked sched_entities.
320 * util_avg may also factor frequency scaling and CPU capacity scaling:
322 * util_avg = running% * SCHED_CAPACITY_SCALE * freq% * capacity%
324 * where freq% is the same as above, and capacity% is the CPU capacity
325 * normalized to the greatest capacity (due to uarch differences, etc).
327 * N.B., the above ratios (runnable%, running%, freq%, and capacity%)
328 * themselves are in the range of [0, 1]. To do fixed point arithmetics,
329 * we therefore scale them to as large a range as necessary. This is for
330 * example reflected by util_avg's SCHED_CAPACITY_SCALE.
334 * The 64-bit load_sum can have 4353082796 (=2^64/47742/88761) entities
335 * with the highest load (=88761), always runnable on a single cfs_rq,
336 * and should not overflow as the number already hits PID_MAX_LIMIT.
338 * For all other cases (including 32-bit kernels), struct load_weight's
339 * weight will overflow first before we do, because:
341 * Max(load_avg) <= Max(load.weight)
343 * Then it is the load_weight's responsibility to consider overflow
347 u64 last_update_time, load_sum;
348 u32 util_sum, period_contrib;
349 unsigned long load_avg, util_avg;
352 #ifdef CONFIG_SCHEDSTATS
353 struct sched_statistics {
363 s64 sum_sleep_runtime;
370 u64 nr_migrations_cold;
371 u64 nr_failed_migrations_affine;
372 u64 nr_failed_migrations_running;
373 u64 nr_failed_migrations_hot;
374 u64 nr_forced_migrations;
378 u64 nr_wakeups_migrate;
379 u64 nr_wakeups_local;
380 u64 nr_wakeups_remote;
381 u64 nr_wakeups_affine;
382 u64 nr_wakeups_affine_attempts;
383 u64 nr_wakeups_passive;
388 struct sched_entity {
389 struct load_weight load; /* for load-balancing */
390 struct rb_node run_node;
391 struct list_head group_node;
395 u64 sum_exec_runtime;
397 u64 prev_sum_exec_runtime;
401 #ifdef CONFIG_SCHEDSTATS
402 struct sched_statistics statistics;
405 #ifdef CONFIG_FAIR_GROUP_SCHED
407 struct sched_entity *parent;
408 /* rq on which this entity is (to be) queued: */
409 struct cfs_rq *cfs_rq;
410 /* rq "owned" by this entity/group: */
416 * Per entity load average tracking.
418 * Put into separate cache line so it does not
419 * collide with read-mostly values above.
421 struct sched_avg avg ____cacheline_aligned_in_smp;
425 struct sched_rt_entity {
426 struct list_head run_list;
427 unsigned long timeout;
428 unsigned long watchdog_stamp;
429 unsigned int time_slice;
430 unsigned short on_rq;
431 unsigned short on_list;
433 struct sched_rt_entity *back;
434 #ifdef CONFIG_RT_GROUP_SCHED
435 struct sched_rt_entity *parent;
436 /* rq on which this entity is (to be) queued: */
438 /* rq "owned" by this entity/group: */
443 struct sched_dl_entity {
444 struct rb_node rb_node;
447 * Original scheduling parameters. Copied here from sched_attr
448 * during sched_setattr(), they will remain the same until
449 * the next sched_setattr().
451 u64 dl_runtime; /* maximum runtime for each instance */
452 u64 dl_deadline; /* relative deadline of each instance */
453 u64 dl_period; /* separation of two instances (period) */
454 u64 dl_bw; /* dl_runtime / dl_deadline */
457 * Actual scheduling parameters. Initialized with the values above,
458 * they are continously updated during task execution. Note that
459 * the remaining runtime could be < 0 in case we are in overrun.
461 s64 runtime; /* remaining runtime for this instance */
462 u64 deadline; /* absolute deadline for this instance */
463 unsigned int flags; /* specifying the scheduler behaviour */
468 * @dl_throttled tells if we exhausted the runtime. If so, the
469 * task has to wait for a replenishment to be performed at the
470 * next firing of dl_timer.
472 * @dl_boosted tells if we are boosted due to DI. If so we are
473 * outside bandwidth enforcement mechanism (but only until we
474 * exit the critical section);
476 * @dl_yielded tells if task gave up the cpu before consuming
477 * all its available runtime during the last job.
479 int dl_throttled, dl_boosted, dl_yielded;
482 * Bandwidth enforcement timer. Each -deadline task has its
483 * own bandwidth to be enforced, thus we need one timer per task.
485 struct hrtimer dl_timer;
493 u8 pad; /* Otherwise the compiler can store garbage here. */
495 u32 s; /* Set of bits. */
498 enum perf_event_task_context {
499 perf_invalid_context = -1,
502 perf_nr_task_contexts,
506 struct wake_q_node *next;
509 /* Track pages that require TLB flushes */
510 struct tlbflush_unmap_batch {
512 * Each bit set is a CPU that potentially has a TLB entry for one of
513 * the PFNs being flushed. See set_tlb_ubc_flush_pending().
515 struct cpumask cpumask;
517 /* True if any bit in cpumask is set */
521 * If true then the PTE was dirty when unmapped. The entry must be
522 * flushed before IO is initiated or a stale TLB entry potentially
523 * allows an update without redirtying the page.
529 #ifdef CONFIG_THREAD_INFO_IN_TASK
531 * For reasons of header soup (see current_thread_info()), this
532 * must be the first element of task_struct.
534 struct thread_info thread_info;
536 volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
539 unsigned int flags; /* per process flags, defined below */
543 struct llist_node wake_entry;
545 #ifdef CONFIG_THREAD_INFO_IN_TASK
546 unsigned int cpu; /* current CPU */
548 unsigned int wakee_flips;
549 unsigned long wakee_flip_decay_ts;
550 struct task_struct *last_wakee;
556 int prio, static_prio, normal_prio;
557 unsigned int rt_priority;
558 const struct sched_class *sched_class;
559 struct sched_entity se;
560 struct sched_rt_entity rt;
561 #ifdef CONFIG_CGROUP_SCHED
562 struct task_group *sched_task_group;
564 struct sched_dl_entity dl;
566 #ifdef CONFIG_PREEMPT_NOTIFIERS
567 /* list of struct preempt_notifier: */
568 struct hlist_head preempt_notifiers;
571 #ifdef CONFIG_BLK_DEV_IO_TRACE
572 unsigned int btrace_seq;
577 cpumask_t cpus_allowed;
579 #ifdef CONFIG_PREEMPT_RCU
580 int rcu_read_lock_nesting;
581 union rcu_special rcu_read_unlock_special;
582 struct list_head rcu_node_entry;
583 struct rcu_node *rcu_blocked_node;
584 #endif /* #ifdef CONFIG_PREEMPT_RCU */
585 #ifdef CONFIG_TASKS_RCU
586 unsigned long rcu_tasks_nvcsw;
587 bool rcu_tasks_holdout;
588 struct list_head rcu_tasks_holdout_list;
589 int rcu_tasks_idle_cpu;
590 #endif /* #ifdef CONFIG_TASKS_RCU */
592 #ifdef CONFIG_SCHED_INFO
593 struct sched_info sched_info;
596 struct list_head tasks;
598 struct plist_node pushable_tasks;
599 struct rb_node pushable_dl_tasks;
602 struct mm_struct *mm, *active_mm;
604 /* Per-thread vma caching: */
605 struct vmacache vmacache;
607 #if defined(SPLIT_RSS_COUNTING)
608 struct task_rss_stat rss_stat;
612 int exit_code, exit_signal;
613 int pdeath_signal; /* The signal sent when the parent dies */
614 unsigned long jobctl; /* JOBCTL_*, siglock protected */
616 /* Used for emulating ABI behavior of previous Linux versions */
617 unsigned int personality;
619 /* scheduler bits, serialized by scheduler locks */
620 unsigned sched_reset_on_fork:1;
621 unsigned sched_contributes_to_load:1;
622 unsigned sched_migrated:1;
623 unsigned sched_remote_wakeup:1;
624 unsigned :0; /* force alignment to the next boundary */
626 /* unserialized, strictly 'current' */
627 unsigned in_execve:1; /* bit to tell LSMs we're in execve */
628 unsigned in_iowait:1;
629 #if !defined(TIF_RESTORE_SIGMASK)
630 unsigned restore_sigmask:1;
633 unsigned memcg_may_oom:1;
635 unsigned memcg_kmem_skip_account:1;
638 #ifdef CONFIG_COMPAT_BRK
639 unsigned brk_randomized:1;
642 unsigned long atomic_flags; /* Flags needing atomic access. */
644 struct restart_block restart_block;
649 #ifdef CONFIG_CC_STACKPROTECTOR
650 /* Canary value for the -fstack-protector gcc feature */
651 unsigned long stack_canary;
654 * pointers to (original) parent process, youngest child, younger sibling,
655 * older sibling, respectively. (p->father can be replaced with
656 * p->real_parent->pid)
658 struct task_struct __rcu *real_parent; /* real parent process */
659 struct task_struct __rcu *parent; /* recipient of SIGCHLD, wait4() reports */
661 * children/sibling forms the list of my natural children
663 struct list_head children; /* list of my children */
664 struct list_head sibling; /* linkage in my parent's children list */
665 struct task_struct *group_leader; /* threadgroup leader */
668 * ptraced is the list of tasks this task is using ptrace on.
669 * This includes both natural children and PTRACE_ATTACH targets.
670 * p->ptrace_entry is p's link on the p->parent->ptraced list.
672 struct list_head ptraced;
673 struct list_head ptrace_entry;
675 /* PID/PID hash table linkage. */
676 struct pid_link pids[PIDTYPE_MAX];
677 struct list_head thread_group;
678 struct list_head thread_node;
680 struct completion *vfork_done; /* for vfork() */
681 int __user *set_child_tid; /* CLONE_CHILD_SETTID */
682 int __user *clear_child_tid; /* CLONE_CHILD_CLEARTID */
685 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
686 u64 utimescaled, stimescaled;
689 struct prev_cputime prev_cputime;
690 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
691 seqcount_t vtime_seqcount;
692 unsigned long long vtime_snap;
694 /* Task is sleeping or running in a CPU with VTIME inactive */
696 /* Task runs in userspace in a CPU with VTIME active */
698 /* Task runs in kernelspace in a CPU with VTIME active */
703 #ifdef CONFIG_NO_HZ_FULL
704 atomic_t tick_dep_mask;
706 unsigned long nvcsw, nivcsw; /* context switch counts */
707 u64 start_time; /* monotonic time in nsec */
708 u64 real_start_time; /* boot based time in nsec */
709 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
710 unsigned long min_flt, maj_flt;
712 #ifdef CONFIG_POSIX_TIMERS
713 struct task_cputime cputime_expires;
714 struct list_head cpu_timers[3];
717 /* process credentials */
718 const struct cred __rcu *ptracer_cred; /* Tracer's credentials at attach */
719 const struct cred __rcu *real_cred; /* objective and real subjective task
720 * credentials (COW) */
721 const struct cred __rcu *cred; /* effective (overridable) subjective task
722 * credentials (COW) */
723 char comm[TASK_COMM_LEN]; /* executable name excluding path
724 - access with [gs]et_task_comm (which lock
726 - initialized normally by setup_new_exec */
727 /* file system info */
728 struct nameidata *nameidata;
729 #ifdef CONFIG_SYSVIPC
731 struct sysv_sem sysvsem;
732 struct sysv_shm sysvshm;
734 #ifdef CONFIG_DETECT_HUNG_TASK
735 /* hung task detection */
736 unsigned long last_switch_count;
738 /* filesystem information */
739 struct fs_struct *fs;
740 /* open file information */
741 struct files_struct *files;
743 struct nsproxy *nsproxy;
744 /* signal handlers */
745 struct signal_struct *signal;
746 struct sighand_struct *sighand;
748 sigset_t blocked, real_blocked;
749 sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */
750 struct sigpending pending;
752 unsigned long sas_ss_sp;
754 unsigned sas_ss_flags;
756 struct callback_head *task_works;
758 struct audit_context *audit_context;
759 #ifdef CONFIG_AUDITSYSCALL
761 unsigned int sessionid;
763 struct seccomp seccomp;
765 /* Thread group tracking */
768 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed,
770 spinlock_t alloc_lock;
772 /* Protection of the PI data structures: */
773 raw_spinlock_t pi_lock;
775 struct wake_q_node wake_q;
777 #ifdef CONFIG_RT_MUTEXES
778 /* PI waiters blocked on a rt_mutex held by this task */
779 struct rb_root pi_waiters;
780 struct rb_node *pi_waiters_leftmost;
781 /* Deadlock detection and priority inheritance handling */
782 struct rt_mutex_waiter *pi_blocked_on;
785 #ifdef CONFIG_DEBUG_MUTEXES
786 /* mutex deadlock detection */
787 struct mutex_waiter *blocked_on;
789 #ifdef CONFIG_TRACE_IRQFLAGS
790 unsigned int irq_events;
791 unsigned long hardirq_enable_ip;
792 unsigned long hardirq_disable_ip;
793 unsigned int hardirq_enable_event;
794 unsigned int hardirq_disable_event;
795 int hardirqs_enabled;
797 unsigned long softirq_disable_ip;
798 unsigned long softirq_enable_ip;
799 unsigned int softirq_disable_event;
800 unsigned int softirq_enable_event;
801 int softirqs_enabled;
804 #ifdef CONFIG_LOCKDEP
805 # define MAX_LOCK_DEPTH 48UL
808 unsigned int lockdep_recursion;
809 struct held_lock held_locks[MAX_LOCK_DEPTH];
810 gfp_t lockdep_reclaim_gfp;
813 unsigned int in_ubsan;
816 /* journalling filesystem info */
819 /* stacked block device info */
820 struct bio_list *bio_list;
824 struct blk_plug *plug;
828 struct reclaim_state *reclaim_state;
830 struct backing_dev_info *backing_dev_info;
832 struct io_context *io_context;
834 unsigned long ptrace_message;
835 siginfo_t *last_siginfo; /* For ptrace use. */
836 struct task_io_accounting ioac;
837 #if defined(CONFIG_TASK_XACCT)
838 u64 acct_rss_mem1; /* accumulated rss usage */
839 u64 acct_vm_mem1; /* accumulated virtual memory usage */
840 u64 acct_timexpd; /* stime + utime since last update */
842 #ifdef CONFIG_CPUSETS
843 nodemask_t mems_allowed; /* Protected by alloc_lock */
844 seqcount_t mems_allowed_seq; /* Seqence no to catch updates */
845 int cpuset_mem_spread_rotor;
846 int cpuset_slab_spread_rotor;
848 #ifdef CONFIG_CGROUPS
849 /* Control Group info protected by css_set_lock */
850 struct css_set __rcu *cgroups;
851 /* cg_list protected by css_set_lock and tsk->alloc_lock */
852 struct list_head cg_list;
854 #ifdef CONFIG_INTEL_RDT_A
858 struct robust_list_head __user *robust_list;
860 struct compat_robust_list_head __user *compat_robust_list;
862 struct list_head pi_state_list;
863 struct futex_pi_state *pi_state_cache;
865 #ifdef CONFIG_PERF_EVENTS
866 struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
867 struct mutex perf_event_mutex;
868 struct list_head perf_event_list;
870 #ifdef CONFIG_DEBUG_PREEMPT
871 unsigned long preempt_disable_ip;
874 struct mempolicy *mempolicy; /* Protected by alloc_lock */
876 short pref_node_fork;
878 #ifdef CONFIG_NUMA_BALANCING
880 unsigned int numa_scan_period;
881 unsigned int numa_scan_period_max;
882 int numa_preferred_nid;
883 unsigned long numa_migrate_retry;
884 u64 node_stamp; /* migration stamp */
885 u64 last_task_numa_placement;
886 u64 last_sum_exec_runtime;
887 struct callback_head numa_work;
889 struct list_head numa_entry;
890 struct numa_group *numa_group;
893 * numa_faults is an array split into four regions:
894 * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
895 * in this precise order.
897 * faults_memory: Exponential decaying average of faults on a per-node
898 * basis. Scheduling placement decisions are made based on these
899 * counts. The values remain static for the duration of a PTE scan.
900 * faults_cpu: Track the nodes the process was running on when a NUMA
901 * hinting fault was incurred.
902 * faults_memory_buffer and faults_cpu_buffer: Record faults per node
903 * during the current scan window. When the scan completes, the counts
904 * in faults_memory and faults_cpu decay and these values are copied.
906 unsigned long *numa_faults;
907 unsigned long total_numa_faults;
910 * numa_faults_locality tracks if faults recorded during the last
911 * scan window were remote/local or failed to migrate. The task scan
912 * period is adapted based on the locality of the faults with different
913 * weights depending on whether they were shared or private faults
915 unsigned long numa_faults_locality[3];
917 unsigned long numa_pages_migrated;
918 #endif /* CONFIG_NUMA_BALANCING */
920 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
921 struct tlbflush_unmap_batch tlb_ubc;
927 * cache last used pipe for splice
929 struct pipe_inode_info *splice_pipe;
931 struct page_frag task_frag;
933 #ifdef CONFIG_TASK_DELAY_ACCT
934 struct task_delay_info *delays;
937 #ifdef CONFIG_FAULT_INJECTION
941 * when (nr_dirtied >= nr_dirtied_pause), it's time to call
942 * balance_dirty_pages() for some dirty throttling pause
945 int nr_dirtied_pause;
946 unsigned long dirty_paused_when; /* start of a write-and-pause period */
948 #ifdef CONFIG_LATENCYTOP
949 int latency_record_count;
950 struct latency_record latency_record[LT_SAVECOUNT];
953 * time slack values; these are used to round up poll() and
954 * select() etc timeout values. These are in nanoseconds.
957 u64 default_timer_slack_ns;
960 unsigned int kasan_depth;
962 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
963 /* Index of current stored address in ret_stack */
965 /* Stack of return addresses for return function tracing */
966 struct ftrace_ret_stack *ret_stack;
967 /* time stamp for last schedule */
968 unsigned long long ftrace_timestamp;
970 * Number of functions that haven't been traced
971 * because of depth overrun.
973 atomic_t trace_overrun;
974 /* Pause for the tracing */
975 atomic_t tracing_graph_pause;
977 #ifdef CONFIG_TRACING
978 /* state flags for use by tracers */
980 /* bitmask and counter of trace recursion */
981 unsigned long trace_recursion;
982 #endif /* CONFIG_TRACING */
984 /* Coverage collection mode enabled for this task (0 if disabled). */
985 enum kcov_mode kcov_mode;
986 /* Size of the kcov_area. */
988 /* Buffer for coverage collection. */
990 /* kcov desciptor wired with this task or NULL. */
994 struct mem_cgroup *memcg_in_oom;
995 gfp_t memcg_oom_gfp_mask;
998 /* number of pages to reclaim on returning to userland */
999 unsigned int memcg_nr_pages_over_high;
1001 #ifdef CONFIG_UPROBES
1002 struct uprobe_task *utask;
1004 #if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
1005 unsigned int sequential_io;
1006 unsigned int sequential_io_avg;
1008 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1009 unsigned long task_state_change;
1011 int pagefault_disabled;
1013 struct task_struct *oom_reaper_list;
1015 #ifdef CONFIG_VMAP_STACK
1016 struct vm_struct *stack_vm_area;
1018 #ifdef CONFIG_THREAD_INFO_IN_TASK
1019 /* A live task holds one reference. */
1020 atomic_t stack_refcount;
1022 /* CPU-specific state of this task */
1023 struct thread_struct thread;
1025 * WARNING: on x86, 'thread_struct' contains a variable-sized
1026 * structure. It *MUST* be at the end of 'task_struct'.
1028 * Do not put anything below here!
1032 static inline struct pid *task_pid(struct task_struct *task)
1034 return task->pids[PIDTYPE_PID].pid;
1037 static inline struct pid *task_tgid(struct task_struct *task)
1039 return task->group_leader->pids[PIDTYPE_PID].pid;
1043 * Without tasklist or rcu lock it is not safe to dereference
1044 * the result of task_pgrp/task_session even if task == current,
1045 * we can race with another thread doing sys_setsid/sys_setpgid.
1047 static inline struct pid *task_pgrp(struct task_struct *task)
1049 return task->group_leader->pids[PIDTYPE_PGID].pid;
1052 static inline struct pid *task_session(struct task_struct *task)
1054 return task->group_leader->pids[PIDTYPE_SID].pid;
1058 * the helpers to get the task's different pids as they are seen
1059 * from various namespaces
1061 * task_xid_nr() : global id, i.e. the id seen from the init namespace;
1062 * task_xid_vnr() : virtual id, i.e. the id seen from the pid namespace of
1064 * task_xid_nr_ns() : id seen from the ns specified;
1066 * set_task_vxid() : assigns a virtual id to a task;
1068 * see also pid_nr() etc in include/linux/pid.h
1070 pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
1071 struct pid_namespace *ns);
1073 static inline pid_t task_pid_nr(struct task_struct *tsk)
1078 static inline pid_t task_pid_nr_ns(struct task_struct *tsk,
1079 struct pid_namespace *ns)
1081 return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1084 static inline pid_t task_pid_vnr(struct task_struct *tsk)
1086 return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1090 static inline pid_t task_tgid_nr(struct task_struct *tsk)
1095 pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);
1097 static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1099 return pid_vnr(task_tgid(tsk));
1103 static inline int pid_alive(const struct task_struct *p);
1104 static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)
1110 pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
1116 static inline pid_t task_ppid_nr(const struct task_struct *tsk)
1118 return task_ppid_nr_ns(tsk, &init_pid_ns);
1121 static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,
1122 struct pid_namespace *ns)
1124 return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1127 static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1129 return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1133 static inline pid_t task_session_nr_ns(struct task_struct *tsk,
1134 struct pid_namespace *ns)
1136 return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1139 static inline pid_t task_session_vnr(struct task_struct *tsk)
1141 return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1144 /* obsolete, do not use */
1145 static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1147 return task_pgrp_nr_ns(tsk, &init_pid_ns);
1151 * pid_alive - check that a task structure is not stale
1152 * @p: Task structure to be checked.
1154 * Test if a process is not yet dead (at most zombie state)
1155 * If pid_alive fails, then pointers within the task structure
1156 * can be stale and must not be dereferenced.
1158 * Return: 1 if the process is alive. 0 otherwise.
1160 static inline int pid_alive(const struct task_struct *p)
1162 return p->pids[PIDTYPE_PID].pid != NULL;
1166 * is_global_init - check if a task structure is init. Since init
1167 * is free to have sub-threads we need to check tgid.
1168 * @tsk: Task structure to be checked.
1170 * Check if a task structure is the first user space task the kernel created.
1172 * Return: 1 if the task structure is init. 0 otherwise.
1174 static inline int is_global_init(struct task_struct *tsk)
1176 return task_tgid_nr(tsk) == 1;
1179 extern struct pid *cad_pid;
1181 extern void free_task(struct task_struct *tsk);
1182 #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
1184 extern void __put_task_struct(struct task_struct *t);
1186 static inline void put_task_struct(struct task_struct *t)
1188 if (atomic_dec_and_test(&t->usage))
1189 __put_task_struct(t);
1192 struct task_struct *task_rcu_dereference(struct task_struct **ptask);
1193 struct task_struct *try_get_task_struct(struct task_struct **ptask);
1198 #define PF_IDLE 0x00000002 /* I am an IDLE thread */
1199 #define PF_EXITING 0x00000004 /* getting shut down */
1200 #define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
1201 #define PF_VCPU 0x00000010 /* I'm a virtual CPU */
1202 #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */
1203 #define PF_FORKNOEXEC 0x00000040 /* forked but didn't exec */
1204 #define PF_MCE_PROCESS 0x00000080 /* process policy on mce errors */
1205 #define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
1206 #define PF_DUMPCORE 0x00000200 /* dumped core */
1207 #define PF_SIGNALED 0x00000400 /* killed by a signal */
1208 #define PF_MEMALLOC 0x00000800 /* Allocating memory */
1209 #define PF_NPROC_EXCEEDED 0x00001000 /* set_user noticed that RLIMIT_NPROC was exceeded */
1210 #define PF_USED_MATH 0x00002000 /* if unset the fpu must be initialized before use */
1211 #define PF_USED_ASYNC 0x00004000 /* used async_schedule*(), used by module init */
1212 #define PF_NOFREEZE 0x00008000 /* this thread should not be frozen */
1213 #define PF_FROZEN 0x00010000 /* frozen for system suspend */
1214 #define PF_FSTRANS 0x00020000 /* inside a filesystem transaction */
1215 #define PF_KSWAPD 0x00040000 /* I am kswapd */
1216 #define PF_MEMALLOC_NOIO 0x00080000 /* Allocating memory without IO involved */
1217 #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */
1218 #define PF_KTHREAD 0x00200000 /* I am a kernel thread */
1219 #define PF_RANDOMIZE 0x00400000 /* randomize virtual address space */
1220 #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */
1221 #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_allowed */
1222 #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
1223 #define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
1224 #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
1225 #define PF_SUSPEND_TASK 0x80000000 /* this thread called freeze_processes and should not be frozen */
1228 * Only the _current_ task can read/write to tsk->flags, but other
1229 * tasks can access tsk->flags in readonly mode for example
1230 * with tsk_used_math (like during threaded core dumping).
1231 * There is however an exception to this rule during ptrace
1232 * or during fork: the ptracer task is allowed to write to the
1233 * child->flags of its traced child (same goes for fork, the parent
1234 * can write to the child->flags), because we're guaranteed the
1235 * child is not running and in turn not changing child->flags
1236 * at the same time the parent does it.
1238 #define clear_stopped_child_used_math(child) do { (child)->flags &= ~PF_USED_MATH; } while (0)
1239 #define set_stopped_child_used_math(child) do { (child)->flags |= PF_USED_MATH; } while (0)
1240 #define clear_used_math() clear_stopped_child_used_math(current)
1241 #define set_used_math() set_stopped_child_used_math(current)
1242 #define conditional_stopped_child_used_math(condition, child) \
1243 do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1244 #define conditional_used_math(condition) \
1245 conditional_stopped_child_used_math(condition, current)
1246 #define copy_to_stopped_child_used_math(child) \
1247 do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1248 /* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1249 #define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
1250 #define used_math() tsk_used_math(current)
1252 /* Per-process atomic flags. */
1253 #define PFA_NO_NEW_PRIVS 0 /* May not gain new privileges. */
1254 #define PFA_SPREAD_PAGE 1 /* Spread page cache over cpuset */
1255 #define PFA_SPREAD_SLAB 2 /* Spread some slab caches over cpuset */
1256 #define PFA_LMK_WAITING 3 /* Lowmemorykiller is waiting */
1259 #define TASK_PFA_TEST(name, func) \
1260 static inline bool task_##func(struct task_struct *p) \
1261 { return test_bit(PFA_##name, &p->atomic_flags); }
1262 #define TASK_PFA_SET(name, func) \
1263 static inline void task_set_##func(struct task_struct *p) \
1264 { set_bit(PFA_##name, &p->atomic_flags); }
1265 #define TASK_PFA_CLEAR(name, func) \
1266 static inline void task_clear_##func(struct task_struct *p) \
1267 { clear_bit(PFA_##name, &p->atomic_flags); }
1269 TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
1270 TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
1272 TASK_PFA_TEST(SPREAD_PAGE, spread_page)
1273 TASK_PFA_SET(SPREAD_PAGE, spread_page)
1274 TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
1276 TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
1277 TASK_PFA_SET(SPREAD_SLAB, spread_slab)
1278 TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
1280 TASK_PFA_TEST(LMK_WAITING, lmk_waiting)
1281 TASK_PFA_SET(LMK_WAITING, lmk_waiting)
1283 static inline void tsk_restore_flags(struct task_struct *task,
1284 unsigned long orig_flags, unsigned long flags)
1286 task->flags &= ~flags;
1287 task->flags |= orig_flags & flags;
1290 extern int cpuset_cpumask_can_shrink(const struct cpumask *cur,
1291 const struct cpumask *trial);
1292 extern int task_can_attach(struct task_struct *p,
1293 const struct cpumask *cs_cpus_allowed);
1295 extern void do_set_cpus_allowed(struct task_struct *p,
1296 const struct cpumask *new_mask);
1298 extern int set_cpus_allowed_ptr(struct task_struct *p,
1299 const struct cpumask *new_mask);
1301 static inline void do_set_cpus_allowed(struct task_struct *p,
1302 const struct cpumask *new_mask)
1305 static inline int set_cpus_allowed_ptr(struct task_struct *p,
1306 const struct cpumask *new_mask)
1308 if (!cpumask_test_cpu(0, new_mask))
1314 #ifndef cpu_relax_yield
1315 #define cpu_relax_yield() cpu_relax()
1318 /* sched_exec is called by processes performing an exec */
1320 extern void sched_exec(void);
1322 #define sched_exec() {}
1325 extern int yield_to(struct task_struct *p, bool preempt);
1326 extern void set_user_nice(struct task_struct *p, long nice);
1327 extern int task_prio(const struct task_struct *p);
1329 * task_nice - return the nice value of a given task.
1330 * @p: the task in question.
1332 * Return: The nice value [ -20 ... 0 ... 19 ].
1334 static inline int task_nice(const struct task_struct *p)
1336 return PRIO_TO_NICE((p)->static_prio);
1338 extern int can_nice(const struct task_struct *p, const int nice);
1339 extern int task_curr(const struct task_struct *p);
1340 extern int idle_cpu(int cpu);
1341 extern int sched_setscheduler(struct task_struct *, int,
1342 const struct sched_param *);
1343 extern int sched_setscheduler_nocheck(struct task_struct *, int,
1344 const struct sched_param *);
1345 extern int sched_setattr(struct task_struct *,
1346 const struct sched_attr *);
1347 extern struct task_struct *idle_task(int cpu);
1349 * is_idle_task - is the specified task an idle task?
1350 * @p: the task in question.
1352 * Return: 1 if @p is an idle task. 0 otherwise.
1354 static inline bool is_idle_task(const struct task_struct *p)
1356 return !!(p->flags & PF_IDLE);
1358 extern struct task_struct *curr_task(int cpu);
1359 extern void ia64_set_curr_task(int cpu, struct task_struct *p);
1363 union thread_union {
1364 #ifndef CONFIG_THREAD_INFO_IN_TASK
1365 struct thread_info thread_info;
1367 unsigned long stack[THREAD_SIZE/sizeof(long)];
1370 #ifdef CONFIG_THREAD_INFO_IN_TASK
1371 static inline struct thread_info *task_thread_info(struct task_struct *task)
1373 return &task->thread_info;
1375 #elif !defined(__HAVE_THREAD_FUNCTIONS)
1376 # define task_thread_info(task) ((struct thread_info *)(task)->stack)
1379 #ifndef __HAVE_ARCH_KSTACK_END
1380 static inline int kstack_end(void *addr)
1382 /* Reliable end of stack detection:
1383 * Some APM bios versions misalign the stack
1385 return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*)));
1389 extern struct pid_namespace init_pid_ns;
1392 * find a task by one of its numerical ids
1394 * find_task_by_pid_ns():
1395 * finds a task by its pid in the specified namespace
1396 * find_task_by_vpid():
1397 * finds a task by its virtual pid
1399 * see also find_vpid() etc in include/linux/pid.h
1402 extern struct task_struct *find_task_by_vpid(pid_t nr);
1403 extern struct task_struct *find_task_by_pid_ns(pid_t nr,
1404 struct pid_namespace *ns);
1406 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
1407 extern int wake_up_process(struct task_struct *tsk);
1408 extern void wake_up_new_task(struct task_struct *tsk);
1410 extern void kick_process(struct task_struct *tsk);
1412 static inline void kick_process(struct task_struct *tsk) { }
1415 extern void exit_files(struct task_struct *);
1417 extern void exit_itimers(struct signal_struct *);
1419 extern int do_execve(struct filename *,
1420 const char __user * const __user *,
1421 const char __user * const __user *);
1422 extern int do_execveat(int, struct filename *,
1423 const char __user * const __user *,
1424 const char __user * const __user *,
1427 extern void __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
1428 static inline void set_task_comm(struct task_struct *tsk, const char *from)
1430 __set_task_comm(tsk, from, false);
1432 extern char *get_task_comm(char *to, struct task_struct *tsk);
1435 void scheduler_ipi(void);
1436 extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
1438 static inline void scheduler_ipi(void) { }
1439 static inline unsigned long wait_task_inactive(struct task_struct *p,
1446 /* set thread flags in other task's structures
1447 * - see asm/thread_info.h for TIF_xxxx flags available
1449 static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
1451 set_ti_thread_flag(task_thread_info(tsk), flag);
1454 static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1456 clear_ti_thread_flag(task_thread_info(tsk), flag);
1459 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
1461 return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
1464 static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1466 return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
1469 static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
1471 return test_ti_thread_flag(task_thread_info(tsk), flag);
1474 static inline void set_tsk_need_resched(struct task_struct *tsk)
1476 set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
1479 static inline void clear_tsk_need_resched(struct task_struct *tsk)
1481 clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
1484 static inline int test_tsk_need_resched(struct task_struct *tsk)
1486 return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
1490 * cond_resched() and cond_resched_lock(): latency reduction via
1491 * explicit rescheduling in places that are safe. The return
1492 * value indicates whether a reschedule was done in fact.
1493 * cond_resched_lock() will drop the spinlock before scheduling,
1494 * cond_resched_softirq() will enable bhs before scheduling.
1496 #ifndef CONFIG_PREEMPT
1497 extern int _cond_resched(void);
1499 static inline int _cond_resched(void) { return 0; }
1502 #define cond_resched() ({ \
1503 ___might_sleep(__FILE__, __LINE__, 0); \
1507 extern int __cond_resched_lock(spinlock_t *lock);
1509 #define cond_resched_lock(lock) ({ \
1510 ___might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);\
1511 __cond_resched_lock(lock); \
1514 extern int __cond_resched_softirq(void);
1516 #define cond_resched_softirq() ({ \
1517 ___might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET); \
1518 __cond_resched_softirq(); \
1521 static inline void cond_resched_rcu(void)
1523 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
1531 * Does a critical section need to be broken due to another
1532 * task waiting?: (technically does not depend on CONFIG_PREEMPT,
1533 * but a general need for low latency)
1535 static inline int spin_needbreak(spinlock_t *lock)
1537 #ifdef CONFIG_PREEMPT
1538 return spin_is_contended(lock);
1544 static __always_inline bool need_resched(void)
1546 return unlikely(tif_need_resched());
1550 * Wrappers for p->thread_info->cpu access. No-op on UP.
1554 static inline unsigned int task_cpu(const struct task_struct *p)
1556 #ifdef CONFIG_THREAD_INFO_IN_TASK
1559 return task_thread_info(p)->cpu;
1563 static inline int task_node(const struct task_struct *p)
1565 return cpu_to_node(task_cpu(p));
1568 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
1572 static inline unsigned int task_cpu(const struct task_struct *p)
1577 static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
1581 #endif /* CONFIG_SMP */
1584 * In order to reduce various lock holder preemption latencies provide an
1585 * interface to see if a vCPU is currently running or not.
1587 * This allows us to terminate optimistic spin loops and block, analogous to
1588 * the native optimistic spin heuristic of testing if the lock owner task is
1591 #ifndef vcpu_is_preempted
1592 # define vcpu_is_preempted(cpu) false
1595 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
1596 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
1598 extern int task_can_switch_user(struct user_struct *up,
1599 struct task_struct *tsk);
1601 #ifndef TASK_SIZE_OF
1602 #define TASK_SIZE_OF(tsk) TASK_SIZE