1 /* SPDX-License-Identifier: GPL-2.0 */
6 * Define 'struct task_struct' and provide the main scheduler
7 * APIs (schedule(), wakeup variants, etc.)
10 #include <uapi/linux/sched.h>
12 #include <asm/current.h>
14 #include <linux/pid.h>
15 #include <linux/sem.h>
16 #include <linux/shm.h>
17 #include <linux/kcov.h>
18 #include <linux/mutex.h>
19 #include <linux/plist.h>
20 #include <linux/hrtimer.h>
21 #include <linux/seccomp.h>
22 #include <linux/nodemask.h>
23 #include <linux/rcupdate.h>
24 #include <linux/resource.h>
25 #include <linux/latencytop.h>
26 #include <linux/sched/prio.h>
27 #include <linux/signal_types.h>
28 #include <linux/mm_types_task.h>
29 #include <linux/task_io_accounting.h>
31 /* task_struct member predeclarations (sorted alphabetically): */
33 struct backing_dev_info;
38 struct futex_pi_state;
43 struct perf_event_context;
45 struct pipe_inode_info;
48 struct robust_list_head;
52 struct sighand_struct;
54 struct task_delay_info;
58 * Task state bitmask. NOTE! These bits are also
59 * encoded in fs/proc/array.c: get_task_state().
61 * We have two separate sets of flags: task->state
62 * is about runnability, while task->exit_state are
63 * about the task exiting. Confusing, but this way
64 * modifying one set can't modify the other one by
68 /* Used in tsk->state: */
69 #define TASK_RUNNING 0x0000
70 #define TASK_INTERRUPTIBLE 0x0001
71 #define TASK_UNINTERRUPTIBLE 0x0002
72 #define __TASK_STOPPED 0x0004
73 #define __TASK_TRACED 0x0008
74 /* Used in tsk->exit_state: */
75 #define EXIT_DEAD 0x0010
76 #define EXIT_ZOMBIE 0x0020
77 #define EXIT_TRACE (EXIT_ZOMBIE | EXIT_DEAD)
78 /* Used in tsk->state again: */
79 #define TASK_PARKED 0x0040
80 #define TASK_DEAD 0x0080
81 #define TASK_WAKEKILL 0x0100
82 #define TASK_WAKING 0x0200
83 #define TASK_NOLOAD 0x0400
84 #define TASK_NEW 0x0800
85 #define TASK_STATE_MAX 0x1000
87 /* Convenience macros for the sake of set_current_state: */
88 #define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
89 #define TASK_STOPPED (TASK_WAKEKILL | __TASK_STOPPED)
90 #define TASK_TRACED (TASK_WAKEKILL | __TASK_TRACED)
92 #define TASK_IDLE (TASK_UNINTERRUPTIBLE | TASK_NOLOAD)
94 /* Convenience macros for the sake of wake_up(): */
95 #define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
96 #define TASK_ALL (TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)
98 /* get_task_state(): */
99 #define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \
100 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
101 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
104 #define task_is_traced(task) ((task->state & __TASK_TRACED) != 0)
106 #define task_is_stopped(task) ((task->state & __TASK_STOPPED) != 0)
108 #define task_is_stopped_or_traced(task) ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
110 #define task_contributes_to_load(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
111 (task->flags & PF_FROZEN) == 0 && \
112 (task->state & TASK_NOLOAD) == 0)
114 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
116 #define __set_current_state(state_value) \
118 current->task_state_change = _THIS_IP_; \
119 current->state = (state_value); \
121 #define set_current_state(state_value) \
123 current->task_state_change = _THIS_IP_; \
124 smp_store_mb(current->state, (state_value)); \
129 * set_current_state() includes a barrier so that the write of current->state
130 * is correctly serialised wrt the caller's subsequent test of whether to
134 * set_current_state(TASK_UNINTERRUPTIBLE);
140 * __set_current_state(TASK_RUNNING);
142 * If the caller does not need such serialisation (because, for instance, the
143 * condition test and condition change and wakeup are under the same lock) then
144 * use __set_current_state().
146 * The above is typically ordered against the wakeup, which does:
148 * need_sleep = false;
149 * wake_up_state(p, TASK_UNINTERRUPTIBLE);
151 * Where wake_up_state() (and all other wakeup primitives) imply enough
152 * barriers to order the store of the variable against wakeup.
154 * Wakeup will do: if (@state & p->state) p->state = TASK_RUNNING, that is,
155 * once it observes the TASK_UNINTERRUPTIBLE store the waking CPU can issue a
156 * TASK_RUNNING store which can collide with __set_current_state(TASK_RUNNING).
158 * This is obviously fine, since they both store the exact same value.
160 * Also see the comments of try_to_wake_up().
162 #define __set_current_state(state_value) do { current->state = (state_value); } while (0)
163 #define set_current_state(state_value) smp_store_mb(current->state, (state_value))
166 /* Task command name length: */
167 #define TASK_COMM_LEN 16
169 extern void scheduler_tick(void);
171 #define MAX_SCHEDULE_TIMEOUT LONG_MAX
173 extern long schedule_timeout(long timeout);
174 extern long schedule_timeout_interruptible(long timeout);
175 extern long schedule_timeout_killable(long timeout);
176 extern long schedule_timeout_uninterruptible(long timeout);
177 extern long schedule_timeout_idle(long timeout);
178 asmlinkage void schedule(void);
179 extern void schedule_preempt_disabled(void);
181 extern int __must_check io_schedule_prepare(void);
182 extern void io_schedule_finish(int token);
183 extern long io_schedule_timeout(long timeout);
184 extern void io_schedule(void);
187 * struct prev_cputime - snapshot of system and user cputime
188 * @utime: time spent in user mode
189 * @stime: time spent in system mode
190 * @lock: protects the above two fields
192 * Stores previous user/system time values such that we can guarantee
195 struct prev_cputime {
196 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
204 * struct task_cputime - collected CPU time counts
205 * @utime: time spent in user mode, in nanoseconds
206 * @stime: time spent in kernel mode, in nanoseconds
207 * @sum_exec_runtime: total time spent on the CPU, in nanoseconds
209 * This structure groups together three kinds of CPU time that are tracked for
210 * threads and thread groups. Most things considering CPU time want to group
211 * these counts together and treat all three of them in parallel.
213 struct task_cputime {
216 unsigned long long sum_exec_runtime;
219 /* Alternate field names when used on cache expirations: */
220 #define virt_exp utime
221 #define prof_exp stime
222 #define sched_exp sum_exec_runtime
225 /* Task is sleeping or running in a CPU with VTIME inactive: */
227 /* Task runs in userspace in a CPU with VTIME active: */
229 /* Task runs in kernelspace in a CPU with VTIME active: */
235 unsigned long long starttime;
236 enum vtime_state state;
243 #ifdef CONFIG_SCHED_INFO
244 /* Cumulative counters: */
246 /* # of times we have run on this CPU: */
247 unsigned long pcount;
249 /* Time spent waiting on a runqueue: */
250 unsigned long long run_delay;
254 /* When did we last run on a CPU? */
255 unsigned long long last_arrival;
257 /* When were we last queued to run? */
258 unsigned long long last_queued;
260 #endif /* CONFIG_SCHED_INFO */
264 * Integer metrics need fixed point arithmetic, e.g., sched/fair
265 * has a few: load, load_avg, util_avg, freq, and capacity.
267 * We define a basic fixed point arithmetic range, and then formalize
268 * all these metrics based on that basic range.
270 # define SCHED_FIXEDPOINT_SHIFT 10
271 # define SCHED_FIXEDPOINT_SCALE (1L << SCHED_FIXEDPOINT_SHIFT)
274 unsigned long weight;
279 * The load_avg/util_avg accumulates an infinite geometric series
280 * (see __update_load_avg() in kernel/sched/fair.c).
282 * [load_avg definition]
284 * load_avg = runnable% * scale_load_down(load)
286 * where runnable% is the time ratio that a sched_entity is runnable.
287 * For cfs_rq, it is the aggregated load_avg of all runnable and
288 * blocked sched_entities.
290 * load_avg may also take frequency scaling into account:
292 * load_avg = runnable% * scale_load_down(load) * freq%
294 * where freq% is the CPU frequency normalized to the highest frequency.
296 * [util_avg definition]
298 * util_avg = running% * SCHED_CAPACITY_SCALE
300 * where running% is the time ratio that a sched_entity is running on
301 * a CPU. For cfs_rq, it is the aggregated util_avg of all runnable
302 * and blocked sched_entities.
304 * util_avg may also factor frequency scaling and CPU capacity scaling:
306 * util_avg = running% * SCHED_CAPACITY_SCALE * freq% * capacity%
308 * where freq% is the same as above, and capacity% is the CPU capacity
309 * normalized to the greatest capacity (due to uarch differences, etc).
311 * N.B., the above ratios (runnable%, running%, freq%, and capacity%)
312 * themselves are in the range of [0, 1]. To do fixed point arithmetics,
313 * we therefore scale them to as large a range as necessary. This is for
314 * example reflected by util_avg's SCHED_CAPACITY_SCALE.
318 * The 64-bit load_sum can have 4353082796 (=2^64/47742/88761) entities
319 * with the highest load (=88761), always runnable on a single cfs_rq,
320 * and should not overflow as the number already hits PID_MAX_LIMIT.
322 * For all other cases (including 32-bit kernels), struct load_weight's
323 * weight will overflow first before we do, because:
325 * Max(load_avg) <= Max(load.weight)
327 * Then it is the load_weight's responsibility to consider overflow
331 u64 last_update_time;
333 u64 runnable_load_sum;
336 unsigned long load_avg;
337 unsigned long runnable_load_avg;
338 unsigned long util_avg;
341 struct sched_statistics {
342 #ifdef CONFIG_SCHEDSTATS
352 s64 sum_sleep_runtime;
359 u64 nr_migrations_cold;
360 u64 nr_failed_migrations_affine;
361 u64 nr_failed_migrations_running;
362 u64 nr_failed_migrations_hot;
363 u64 nr_forced_migrations;
367 u64 nr_wakeups_migrate;
368 u64 nr_wakeups_local;
369 u64 nr_wakeups_remote;
370 u64 nr_wakeups_affine;
371 u64 nr_wakeups_affine_attempts;
372 u64 nr_wakeups_passive;
377 struct sched_entity {
378 /* For load-balancing: */
379 struct load_weight load;
380 unsigned long runnable_weight;
381 struct rb_node run_node;
382 struct list_head group_node;
386 u64 sum_exec_runtime;
388 u64 prev_sum_exec_runtime;
392 struct sched_statistics statistics;
394 #ifdef CONFIG_FAIR_GROUP_SCHED
396 struct sched_entity *parent;
397 /* rq on which this entity is (to be) queued: */
398 struct cfs_rq *cfs_rq;
399 /* rq "owned" by this entity/group: */
405 * Per entity load average tracking.
407 * Put into separate cache line so it does not
408 * collide with read-mostly values above.
410 struct sched_avg avg ____cacheline_aligned_in_smp;
414 struct sched_rt_entity {
415 struct list_head run_list;
416 unsigned long timeout;
417 unsigned long watchdog_stamp;
418 unsigned int time_slice;
419 unsigned short on_rq;
420 unsigned short on_list;
422 struct sched_rt_entity *back;
423 #ifdef CONFIG_RT_GROUP_SCHED
424 struct sched_rt_entity *parent;
425 /* rq on which this entity is (to be) queued: */
427 /* rq "owned" by this entity/group: */
430 } __randomize_layout;
432 struct sched_dl_entity {
433 struct rb_node rb_node;
436 * Original scheduling parameters. Copied here from sched_attr
437 * during sched_setattr(), they will remain the same until
438 * the next sched_setattr().
440 u64 dl_runtime; /* Maximum runtime for each instance */
441 u64 dl_deadline; /* Relative deadline of each instance */
442 u64 dl_period; /* Separation of two instances (period) */
443 u64 dl_bw; /* dl_runtime / dl_period */
444 u64 dl_density; /* dl_runtime / dl_deadline */
447 * Actual scheduling parameters. Initialized with the values above,
448 * they are continously updated during task execution. Note that
449 * the remaining runtime could be < 0 in case we are in overrun.
451 s64 runtime; /* Remaining runtime for this instance */
452 u64 deadline; /* Absolute deadline for this instance */
453 unsigned int flags; /* Specifying the scheduler behaviour */
458 * @dl_throttled tells if we exhausted the runtime. If so, the
459 * task has to wait for a replenishment to be performed at the
460 * next firing of dl_timer.
462 * @dl_boosted tells if we are boosted due to DI. If so we are
463 * outside bandwidth enforcement mechanism (but only until we
464 * exit the critical section);
466 * @dl_yielded tells if task gave up the CPU before consuming
467 * all its available runtime during the last job.
469 * @dl_non_contending tells if the task is inactive while still
470 * contributing to the active utilization. In other words, it
471 * indicates if the inactive timer has been armed and its handler
472 * has not been executed yet. This flag is useful to avoid race
473 * conditions between the inactive timer handler and the wakeup
476 * @dl_overrun tells if the task asked to be informed about runtime
479 unsigned int dl_throttled : 1;
480 unsigned int dl_boosted : 1;
481 unsigned int dl_yielded : 1;
482 unsigned int dl_non_contending : 1;
483 unsigned int dl_overrun : 1;
486 * Bandwidth enforcement timer. Each -deadline task has its
487 * own bandwidth to be enforced, thus we need one timer per task.
489 struct hrtimer dl_timer;
492 * Inactive timer, responsible for decreasing the active utilization
493 * at the "0-lag time". When a -deadline task blocks, it contributes
494 * to GRUB's active utilization until the "0-lag time", hence a
495 * timer is needed to decrease the active utilization at the correct
498 struct hrtimer inactive_timer;
507 /* Otherwise the compiler can store garbage here: */
510 u32 s; /* Set of bits. */
513 enum perf_event_task_context {
514 perf_invalid_context = -1,
517 perf_nr_task_contexts,
521 struct wake_q_node *next;
525 #ifdef CONFIG_THREAD_INFO_IN_TASK
527 * For reasons of header soup (see current_thread_info()), this
528 * must be the first element of task_struct.
530 struct thread_info thread_info;
532 /* -1 unrunnable, 0 runnable, >0 stopped: */
536 * This begins the randomizable portion of task_struct. Only
537 * scheduling-critical items should be added above here.
539 randomized_struct_fields_start
543 /* Per task flags (PF_*), defined further below: */
548 struct llist_node wake_entry;
550 #ifdef CONFIG_THREAD_INFO_IN_TASK
554 unsigned int wakee_flips;
555 unsigned long wakee_flip_decay_ts;
556 struct task_struct *last_wakee;
565 unsigned int rt_priority;
567 const struct sched_class *sched_class;
568 struct sched_entity se;
569 struct sched_rt_entity rt;
570 #ifdef CONFIG_CGROUP_SCHED
571 struct task_group *sched_task_group;
573 struct sched_dl_entity dl;
575 #ifdef CONFIG_PREEMPT_NOTIFIERS
576 /* List of struct preempt_notifier: */
577 struct hlist_head preempt_notifiers;
580 #ifdef CONFIG_BLK_DEV_IO_TRACE
581 unsigned int btrace_seq;
586 cpumask_t cpus_allowed;
588 #ifdef CONFIG_PREEMPT_RCU
589 int rcu_read_lock_nesting;
590 union rcu_special rcu_read_unlock_special;
591 struct list_head rcu_node_entry;
592 struct rcu_node *rcu_blocked_node;
593 #endif /* #ifdef CONFIG_PREEMPT_RCU */
595 #ifdef CONFIG_TASKS_RCU
596 unsigned long rcu_tasks_nvcsw;
597 u8 rcu_tasks_holdout;
599 int rcu_tasks_idle_cpu;
600 struct list_head rcu_tasks_holdout_list;
601 #endif /* #ifdef CONFIG_TASKS_RCU */
603 struct sched_info sched_info;
605 struct list_head tasks;
607 struct plist_node pushable_tasks;
608 struct rb_node pushable_dl_tasks;
611 struct mm_struct *mm;
612 struct mm_struct *active_mm;
614 /* Per-thread vma caching: */
615 struct vmacache vmacache;
617 #ifdef SPLIT_RSS_COUNTING
618 struct task_rss_stat rss_stat;
623 /* The signal sent when the parent dies: */
625 /* JOBCTL_*, siglock protected: */
626 unsigned long jobctl;
628 /* Used for emulating ABI behavior of previous Linux versions: */
629 unsigned int personality;
631 /* Scheduler bits, serialized by scheduler locks: */
632 unsigned sched_reset_on_fork:1;
633 unsigned sched_contributes_to_load:1;
634 unsigned sched_migrated:1;
635 unsigned sched_remote_wakeup:1;
636 /* Force alignment to the next boundary: */
639 /* Unserialized, strictly 'current' */
641 /* Bit to tell LSMs we're in execve(): */
642 unsigned in_execve:1;
643 unsigned in_iowait:1;
644 #ifndef TIF_RESTORE_SIGMASK
645 unsigned restore_sigmask:1;
648 unsigned memcg_may_oom:1;
650 unsigned memcg_kmem_skip_account:1;
653 #ifdef CONFIG_COMPAT_BRK
654 unsigned brk_randomized:1;
656 #ifdef CONFIG_CGROUPS
657 /* disallow userland-initiated cgroup migration */
658 unsigned no_cgroup_migration:1;
661 unsigned long atomic_flags; /* Flags requiring atomic access. */
663 struct restart_block restart_block;
668 #ifdef CONFIG_CC_STACKPROTECTOR
669 /* Canary value for the -fstack-protector GCC feature: */
670 unsigned long stack_canary;
673 * Pointers to the (original) parent process, youngest child, younger sibling,
674 * older sibling, respectively. (p->father can be replaced with
675 * p->real_parent->pid)
678 /* Real parent process: */
679 struct task_struct __rcu *real_parent;
681 /* Recipient of SIGCHLD, wait4() reports: */
682 struct task_struct __rcu *parent;
685 * Children/sibling form the list of natural children:
687 struct list_head children;
688 struct list_head sibling;
689 struct task_struct *group_leader;
692 * 'ptraced' is the list of tasks this task is using ptrace() on.
694 * This includes both natural children and PTRACE_ATTACH targets.
695 * 'ptrace_entry' is this task's link on the p->parent->ptraced list.
697 struct list_head ptraced;
698 struct list_head ptrace_entry;
700 /* PID/PID hash table linkage. */
701 struct pid_link pids[PIDTYPE_MAX];
702 struct list_head thread_group;
703 struct list_head thread_node;
705 struct completion *vfork_done;
707 /* CLONE_CHILD_SETTID: */
708 int __user *set_child_tid;
710 /* CLONE_CHILD_CLEARTID: */
711 int __user *clear_child_tid;
715 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
720 struct prev_cputime prev_cputime;
721 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
725 #ifdef CONFIG_NO_HZ_FULL
726 atomic_t tick_dep_mask;
728 /* Context switch counts: */
730 unsigned long nivcsw;
732 /* Monotonic time in nsecs: */
735 /* Boot based time in nsecs: */
738 /* MM fault and swap info: this can arguably be seen as either mm-specific or thread-specific: */
739 unsigned long min_flt;
740 unsigned long maj_flt;
742 #ifdef CONFIG_POSIX_TIMERS
743 struct task_cputime cputime_expires;
744 struct list_head cpu_timers[3];
747 /* Process credentials: */
749 /* Tracer's credentials at attach: */
750 const struct cred __rcu *ptracer_cred;
752 /* Objective and real subjective task credentials (COW): */
753 const struct cred __rcu *real_cred;
755 /* Effective (overridable) subjective task credentials (COW): */
756 const struct cred __rcu *cred;
759 * executable name, excluding path.
761 * - normally initialized setup_new_exec()
762 * - access it with [gs]et_task_comm()
763 * - lock it with task_lock()
765 char comm[TASK_COMM_LEN];
767 struct nameidata *nameidata;
769 #ifdef CONFIG_SYSVIPC
770 struct sysv_sem sysvsem;
771 struct sysv_shm sysvshm;
773 #ifdef CONFIG_DETECT_HUNG_TASK
774 unsigned long last_switch_count;
776 /* Filesystem information: */
777 struct fs_struct *fs;
779 /* Open file information: */
780 struct files_struct *files;
783 struct nsproxy *nsproxy;
785 /* Signal handlers: */
786 struct signal_struct *signal;
787 struct sighand_struct *sighand;
789 sigset_t real_blocked;
790 /* Restored if set_restore_sigmask() was used: */
791 sigset_t saved_sigmask;
792 struct sigpending pending;
793 unsigned long sas_ss_sp;
795 unsigned int sas_ss_flags;
797 struct callback_head *task_works;
799 struct audit_context *audit_context;
800 #ifdef CONFIG_AUDITSYSCALL
802 unsigned int sessionid;
804 struct seccomp seccomp;
806 /* Thread group tracking: */
810 /* Protection against (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed, mempolicy: */
811 spinlock_t alloc_lock;
813 /* Protection of the PI data structures: */
814 raw_spinlock_t pi_lock;
816 struct wake_q_node wake_q;
818 #ifdef CONFIG_RT_MUTEXES
819 /* PI waiters blocked on a rt_mutex held by this task: */
820 struct rb_root_cached pi_waiters;
821 /* Updated under owner's pi_lock and rq lock */
822 struct task_struct *pi_top_task;
823 /* Deadlock detection and priority inheritance handling: */
824 struct rt_mutex_waiter *pi_blocked_on;
827 #ifdef CONFIG_DEBUG_MUTEXES
828 /* Mutex deadlock detection: */
829 struct mutex_waiter *blocked_on;
832 #ifdef CONFIG_TRACE_IRQFLAGS
833 unsigned int irq_events;
834 unsigned long hardirq_enable_ip;
835 unsigned long hardirq_disable_ip;
836 unsigned int hardirq_enable_event;
837 unsigned int hardirq_disable_event;
838 int hardirqs_enabled;
840 unsigned long softirq_disable_ip;
841 unsigned long softirq_enable_ip;
842 unsigned int softirq_disable_event;
843 unsigned int softirq_enable_event;
844 int softirqs_enabled;
848 #ifdef CONFIG_LOCKDEP
849 # define MAX_LOCK_DEPTH 48UL
852 unsigned int lockdep_recursion;
853 struct held_lock held_locks[MAX_LOCK_DEPTH];
857 unsigned int in_ubsan;
860 /* Journalling filesystem info: */
863 /* Stacked block device info: */
864 struct bio_list *bio_list;
867 /* Stack plugging: */
868 struct blk_plug *plug;
872 struct reclaim_state *reclaim_state;
874 struct backing_dev_info *backing_dev_info;
876 struct io_context *io_context;
879 unsigned long ptrace_message;
880 siginfo_t *last_siginfo;
882 struct task_io_accounting ioac;
883 #ifdef CONFIG_TASK_XACCT
884 /* Accumulated RSS usage: */
886 /* Accumulated virtual memory usage: */
888 /* stime + utime since last update: */
891 #ifdef CONFIG_CPUSETS
892 /* Protected by ->alloc_lock: */
893 nodemask_t mems_allowed;
894 /* Seqence number to catch updates: */
895 seqcount_t mems_allowed_seq;
896 int cpuset_mem_spread_rotor;
897 int cpuset_slab_spread_rotor;
899 #ifdef CONFIG_CGROUPS
900 /* Control Group info protected by css_set_lock: */
901 struct css_set __rcu *cgroups;
902 /* cg_list protected by css_set_lock and tsk->alloc_lock: */
903 struct list_head cg_list;
905 #ifdef CONFIG_INTEL_RDT
910 struct robust_list_head __user *robust_list;
912 struct compat_robust_list_head __user *compat_robust_list;
914 struct list_head pi_state_list;
915 struct futex_pi_state *pi_state_cache;
917 #ifdef CONFIG_PERF_EVENTS
918 struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
919 struct mutex perf_event_mutex;
920 struct list_head perf_event_list;
922 #ifdef CONFIG_DEBUG_PREEMPT
923 unsigned long preempt_disable_ip;
926 /* Protected by alloc_lock: */
927 struct mempolicy *mempolicy;
929 short pref_node_fork;
931 #ifdef CONFIG_NUMA_BALANCING
933 unsigned int numa_scan_period;
934 unsigned int numa_scan_period_max;
935 int numa_preferred_nid;
936 unsigned long numa_migrate_retry;
937 /* Migration stamp: */
939 u64 last_task_numa_placement;
940 u64 last_sum_exec_runtime;
941 struct callback_head numa_work;
943 struct list_head numa_entry;
944 struct numa_group *numa_group;
947 * numa_faults is an array split into four regions:
948 * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
949 * in this precise order.
951 * faults_memory: Exponential decaying average of faults on a per-node
952 * basis. Scheduling placement decisions are made based on these
953 * counts. The values remain static for the duration of a PTE scan.
954 * faults_cpu: Track the nodes the process was running on when a NUMA
955 * hinting fault was incurred.
956 * faults_memory_buffer and faults_cpu_buffer: Record faults per node
957 * during the current scan window. When the scan completes, the counts
958 * in faults_memory and faults_cpu decay and these values are copied.
960 unsigned long *numa_faults;
961 unsigned long total_numa_faults;
964 * numa_faults_locality tracks if faults recorded during the last
965 * scan window were remote/local or failed to migrate. The task scan
966 * period is adapted based on the locality of the faults with different
967 * weights depending on whether they were shared or private faults
969 unsigned long numa_faults_locality[3];
971 unsigned long numa_pages_migrated;
972 #endif /* CONFIG_NUMA_BALANCING */
974 struct tlbflush_unmap_batch tlb_ubc;
978 /* Cache last used pipe for splice(): */
979 struct pipe_inode_info *splice_pipe;
981 struct page_frag task_frag;
983 #ifdef CONFIG_TASK_DELAY_ACCT
984 struct task_delay_info *delays;
987 #ifdef CONFIG_FAULT_INJECTION
989 unsigned int fail_nth;
992 * When (nr_dirtied >= nr_dirtied_pause), it's time to call
993 * balance_dirty_pages() for a dirty throttling pause:
996 int nr_dirtied_pause;
997 /* Start of a write-and-pause period: */
998 unsigned long dirty_paused_when;
1000 #ifdef CONFIG_LATENCYTOP
1001 int latency_record_count;
1002 struct latency_record latency_record[LT_SAVECOUNT];
1005 * Time slack values; these are used to round up poll() and
1006 * select() etc timeout values. These are in nanoseconds.
1009 u64 default_timer_slack_ns;
1012 unsigned int kasan_depth;
1015 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1016 /* Index of current stored address in ret_stack: */
1019 /* Stack of return addresses for return function tracing: */
1020 struct ftrace_ret_stack *ret_stack;
1022 /* Timestamp for last schedule: */
1023 unsigned long long ftrace_timestamp;
1026 * Number of functions that haven't been traced
1027 * because of depth overrun:
1029 atomic_t trace_overrun;
1031 /* Pause tracing: */
1032 atomic_t tracing_graph_pause;
1035 #ifdef CONFIG_TRACING
1036 /* State flags for use by tracers: */
1037 unsigned long trace;
1039 /* Bitmask and counter of trace recursion: */
1040 unsigned long trace_recursion;
1041 #endif /* CONFIG_TRACING */
1044 /* Coverage collection mode enabled for this task (0 if disabled): */
1045 enum kcov_mode kcov_mode;
1047 /* Size of the kcov_area: */
1048 unsigned int kcov_size;
1050 /* Buffer for coverage collection: */
1053 /* KCOV descriptor wired with this task or NULL: */
1058 struct mem_cgroup *memcg_in_oom;
1059 gfp_t memcg_oom_gfp_mask;
1060 int memcg_oom_order;
1062 /* Number of pages to reclaim on returning to userland: */
1063 unsigned int memcg_nr_pages_over_high;
1066 #ifdef CONFIG_UPROBES
1067 struct uprobe_task *utask;
1069 #if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
1070 unsigned int sequential_io;
1071 unsigned int sequential_io_avg;
1073 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1074 unsigned long task_state_change;
1076 int pagefault_disabled;
1078 struct task_struct *oom_reaper_list;
1080 #ifdef CONFIG_VMAP_STACK
1081 struct vm_struct *stack_vm_area;
1083 #ifdef CONFIG_THREAD_INFO_IN_TASK
1084 /* A live task holds one reference: */
1085 atomic_t stack_refcount;
1087 #ifdef CONFIG_LIVEPATCH
1090 #ifdef CONFIG_SECURITY
1091 /* Used by LSM modules for access restriction: */
1096 * New fields for task_struct should be added above here, so that
1097 * they are included in the randomized portion of task_struct.
1099 randomized_struct_fields_end
1101 /* CPU-specific state of this task: */
1102 struct thread_struct thread;
1105 * WARNING: on x86, 'thread_struct' contains a variable-sized
1106 * structure. It *MUST* be at the end of 'task_struct'.
1108 * Do not put anything below here!
1112 static inline struct pid *task_pid(struct task_struct *task)
1114 return task->pids[PIDTYPE_PID].pid;
1117 static inline struct pid *task_tgid(struct task_struct *task)
1119 return task->group_leader->pids[PIDTYPE_PID].pid;
1123 * Without tasklist or RCU lock it is not safe to dereference
1124 * the result of task_pgrp/task_session even if task == current,
1125 * we can race with another thread doing sys_setsid/sys_setpgid.
1127 static inline struct pid *task_pgrp(struct task_struct *task)
1129 return task->group_leader->pids[PIDTYPE_PGID].pid;
1132 static inline struct pid *task_session(struct task_struct *task)
1134 return task->group_leader->pids[PIDTYPE_SID].pid;
1138 * the helpers to get the task's different pids as they are seen
1139 * from various namespaces
1141 * task_xid_nr() : global id, i.e. the id seen from the init namespace;
1142 * task_xid_vnr() : virtual id, i.e. the id seen from the pid namespace of
1144 * task_xid_nr_ns() : id seen from the ns specified;
1146 * see also pid_nr() etc in include/linux/pid.h
1148 pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, struct pid_namespace *ns);
1150 static inline pid_t task_pid_nr(struct task_struct *tsk)
1155 static inline pid_t task_pid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1157 return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
1160 static inline pid_t task_pid_vnr(struct task_struct *tsk)
1162 return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
1166 static inline pid_t task_tgid_nr(struct task_struct *tsk)
1172 * pid_alive - check that a task structure is not stale
1173 * @p: Task structure to be checked.
1175 * Test if a process is not yet dead (at most zombie state)
1176 * If pid_alive fails, then pointers within the task structure
1177 * can be stale and must not be dereferenced.
1179 * Return: 1 if the process is alive. 0 otherwise.
1181 static inline int pid_alive(const struct task_struct *p)
1183 return p->pids[PIDTYPE_PID].pid != NULL;
1186 static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1188 return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
1191 static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
1193 return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
1197 static inline pid_t task_session_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1199 return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
1202 static inline pid_t task_session_vnr(struct task_struct *tsk)
1204 return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
1207 static inline pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
1209 return __task_pid_nr_ns(tsk, __PIDTYPE_TGID, ns);
1212 static inline pid_t task_tgid_vnr(struct task_struct *tsk)
1214 return __task_pid_nr_ns(tsk, __PIDTYPE_TGID, NULL);
1217 static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)
1223 pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
1229 static inline pid_t task_ppid_nr(const struct task_struct *tsk)
1231 return task_ppid_nr_ns(tsk, &init_pid_ns);
1234 /* Obsolete, do not use: */
1235 static inline pid_t task_pgrp_nr(struct task_struct *tsk)
1237 return task_pgrp_nr_ns(tsk, &init_pid_ns);
1240 #define TASK_REPORT_IDLE (TASK_REPORT + 1)
1241 #define TASK_REPORT_MAX (TASK_REPORT_IDLE << 1)
1243 static inline unsigned int task_state_index(struct task_struct *tsk)
1245 unsigned int tsk_state = READ_ONCE(tsk->state);
1246 unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT;
1248 BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
1250 if (tsk_state == TASK_IDLE)
1251 state = TASK_REPORT_IDLE;
1256 static inline char task_index_to_char(unsigned int state)
1258 static const char state_char[] = "RSDTtXZPI";
1260 BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != sizeof(state_char) - 1);
1262 return state_char[state];
1265 static inline char task_state_to_char(struct task_struct *tsk)
1267 return task_index_to_char(task_state_index(tsk));
1271 * is_global_init - check if a task structure is init. Since init
1272 * is free to have sub-threads we need to check tgid.
1273 * @tsk: Task structure to be checked.
1275 * Check if a task structure is the first user space task the kernel created.
1277 * Return: 1 if the task structure is init. 0 otherwise.
1279 static inline int is_global_init(struct task_struct *tsk)
1281 return task_tgid_nr(tsk) == 1;
1284 extern struct pid *cad_pid;
1289 #define PF_IDLE 0x00000002 /* I am an IDLE thread */
1290 #define PF_EXITING 0x00000004 /* Getting shut down */
1291 #define PF_EXITPIDONE 0x00000008 /* PI exit done on shut down */
1292 #define PF_VCPU 0x00000010 /* I'm a virtual CPU */
1293 #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */
1294 #define PF_FORKNOEXEC 0x00000040 /* Forked but didn't exec */
1295 #define PF_MCE_PROCESS 0x00000080 /* Process policy on mce errors */
1296 #define PF_SUPERPRIV 0x00000100 /* Used super-user privileges */
1297 #define PF_DUMPCORE 0x00000200 /* Dumped core */
1298 #define PF_SIGNALED 0x00000400 /* Killed by a signal */
1299 #define PF_MEMALLOC 0x00000800 /* Allocating memory */
1300 #define PF_NPROC_EXCEEDED 0x00001000 /* set_user() noticed that RLIMIT_NPROC was exceeded */
1301 #define PF_USED_MATH 0x00002000 /* If unset the fpu must be initialized before use */
1302 #define PF_USED_ASYNC 0x00004000 /* Used async_schedule*(), used by module init */
1303 #define PF_NOFREEZE 0x00008000 /* This thread should not be frozen */
1304 #define PF_FROZEN 0x00010000 /* Frozen for system suspend */
1305 #define PF_KSWAPD 0x00020000 /* I am kswapd */
1306 #define PF_MEMALLOC_NOFS 0x00040000 /* All allocation requests will inherit GFP_NOFS */
1307 #define PF_MEMALLOC_NOIO 0x00080000 /* All allocation requests will inherit GFP_NOIO */
1308 #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */
1309 #define PF_KTHREAD 0x00200000 /* I am a kernel thread */
1310 #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */
1311 #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */
1312 #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_allowed */
1313 #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
1314 #define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
1315 #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
1316 #define PF_SUSPEND_TASK 0x80000000 /* This thread called freeze_processes() and should not be frozen */
1319 * Only the _current_ task can read/write to tsk->flags, but other
1320 * tasks can access tsk->flags in readonly mode for example
1321 * with tsk_used_math (like during threaded core dumping).
1322 * There is however an exception to this rule during ptrace
1323 * or during fork: the ptracer task is allowed to write to the
1324 * child->flags of its traced child (same goes for fork, the parent
1325 * can write to the child->flags), because we're guaranteed the
1326 * child is not running and in turn not changing child->flags
1327 * at the same time the parent does it.
1329 #define clear_stopped_child_used_math(child) do { (child)->flags &= ~PF_USED_MATH; } while (0)
1330 #define set_stopped_child_used_math(child) do { (child)->flags |= PF_USED_MATH; } while (0)
1331 #define clear_used_math() clear_stopped_child_used_math(current)
1332 #define set_used_math() set_stopped_child_used_math(current)
1334 #define conditional_stopped_child_used_math(condition, child) \
1335 do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1337 #define conditional_used_math(condition) conditional_stopped_child_used_math(condition, current)
1339 #define copy_to_stopped_child_used_math(child) \
1340 do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1342 /* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1343 #define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
1344 #define used_math() tsk_used_math(current)
1346 static inline bool is_percpu_thread(void)
1349 return (current->flags & PF_NO_SETAFFINITY) &&
1350 (current->nr_cpus_allowed == 1);
1356 /* Per-process atomic flags. */
1357 #define PFA_NO_NEW_PRIVS 0 /* May not gain new privileges. */
1358 #define PFA_SPREAD_PAGE 1 /* Spread page cache over cpuset */
1359 #define PFA_SPREAD_SLAB 2 /* Spread some slab caches over cpuset */
1362 #define TASK_PFA_TEST(name, func) \
1363 static inline bool task_##func(struct task_struct *p) \
1364 { return test_bit(PFA_##name, &p->atomic_flags); }
1366 #define TASK_PFA_SET(name, func) \
1367 static inline void task_set_##func(struct task_struct *p) \
1368 { set_bit(PFA_##name, &p->atomic_flags); }
1370 #define TASK_PFA_CLEAR(name, func) \
1371 static inline void task_clear_##func(struct task_struct *p) \
1372 { clear_bit(PFA_##name, &p->atomic_flags); }
1374 TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
1375 TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
1377 TASK_PFA_TEST(SPREAD_PAGE, spread_page)
1378 TASK_PFA_SET(SPREAD_PAGE, spread_page)
1379 TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
1381 TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
1382 TASK_PFA_SET(SPREAD_SLAB, spread_slab)
1383 TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
1386 current_restore_flags(unsigned long orig_flags, unsigned long flags)
1388 current->flags &= ~flags;
1389 current->flags |= orig_flags & flags;
1392 extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
1393 extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
1395 extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
1396 extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);
1398 static inline void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
1401 static inline int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1403 if (!cpumask_test_cpu(0, new_mask))
1409 #ifndef cpu_relax_yield
1410 #define cpu_relax_yield() cpu_relax()
1413 extern int yield_to(struct task_struct *p, bool preempt);
1414 extern void set_user_nice(struct task_struct *p, long nice);
1415 extern int task_prio(const struct task_struct *p);
1418 * task_nice - return the nice value of a given task.
1419 * @p: the task in question.
1421 * Return: The nice value [ -20 ... 0 ... 19 ].
1423 static inline int task_nice(const struct task_struct *p)
1425 return PRIO_TO_NICE((p)->static_prio);
1428 extern int can_nice(const struct task_struct *p, const int nice);
1429 extern int task_curr(const struct task_struct *p);
1430 extern int idle_cpu(int cpu);
1431 extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *);
1432 extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *);
1433 extern int sched_setattr(struct task_struct *, const struct sched_attr *);
1434 extern int sched_setattr_nocheck(struct task_struct *, const struct sched_attr *);
1435 extern struct task_struct *idle_task(int cpu);
1438 * is_idle_task - is the specified task an idle task?
1439 * @p: the task in question.
1441 * Return: 1 if @p is an idle task. 0 otherwise.
1443 static inline bool is_idle_task(const struct task_struct *p)
1445 return !!(p->flags & PF_IDLE);
1448 extern struct task_struct *curr_task(int cpu);
1449 extern void ia64_set_curr_task(int cpu, struct task_struct *p);
1453 union thread_union {
1454 #ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK
1455 struct task_struct task;
1457 #ifndef CONFIG_THREAD_INFO_IN_TASK
1458 struct thread_info thread_info;
1460 unsigned long stack[THREAD_SIZE/sizeof(long)];
1463 #ifndef CONFIG_THREAD_INFO_IN_TASK
1464 extern struct thread_info init_thread_info;
1467 extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)];
1469 #ifdef CONFIG_THREAD_INFO_IN_TASK
1470 static inline struct thread_info *task_thread_info(struct task_struct *task)
1472 return &task->thread_info;
1474 #elif !defined(__HAVE_THREAD_FUNCTIONS)
1475 # define task_thread_info(task) ((struct thread_info *)(task)->stack)
1479 * find a task by one of its numerical ids
1481 * find_task_by_pid_ns():
1482 * finds a task by its pid in the specified namespace
1483 * find_task_by_vpid():
1484 * finds a task by its virtual pid
1486 * see also find_vpid() etc in include/linux/pid.h
1489 extern struct task_struct *find_task_by_vpid(pid_t nr);
1490 extern struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns);
1492 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
1493 extern int wake_up_process(struct task_struct *tsk);
1494 extern void wake_up_new_task(struct task_struct *tsk);
1497 extern void kick_process(struct task_struct *tsk);
1499 static inline void kick_process(struct task_struct *tsk) { }
1502 extern void __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
1504 static inline void set_task_comm(struct task_struct *tsk, const char *from)
1506 __set_task_comm(tsk, from, false);
1509 extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
1510 #define get_task_comm(buf, tsk) ({ \
1511 BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN); \
1512 __get_task_comm(buf, sizeof(buf), tsk); \
1516 void scheduler_ipi(void);
1517 extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
1519 static inline void scheduler_ipi(void) { }
1520 static inline unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1527 * Set thread flags in other task's structures.
1528 * See asm/thread_info.h for TIF_xxxx flags available:
1530 static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
1532 set_ti_thread_flag(task_thread_info(tsk), flag);
1535 static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1537 clear_ti_thread_flag(task_thread_info(tsk), flag);
1540 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
1542 return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
1545 static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1547 return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
1550 static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
1552 return test_ti_thread_flag(task_thread_info(tsk), flag);
1555 static inline void set_tsk_need_resched(struct task_struct *tsk)
1557 set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
1560 static inline void clear_tsk_need_resched(struct task_struct *tsk)
1562 clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
1565 static inline int test_tsk_need_resched(struct task_struct *tsk)
1567 return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
1571 * cond_resched() and cond_resched_lock(): latency reduction via
1572 * explicit rescheduling in places that are safe. The return
1573 * value indicates whether a reschedule was done in fact.
1574 * cond_resched_lock() will drop the spinlock before scheduling,
1575 * cond_resched_softirq() will enable bhs before scheduling.
1577 #ifndef CONFIG_PREEMPT
1578 extern int _cond_resched(void);
1580 static inline int _cond_resched(void) { return 0; }
1583 #define cond_resched() ({ \
1584 ___might_sleep(__FILE__, __LINE__, 0); \
1588 extern int __cond_resched_lock(spinlock_t *lock);
1590 #define cond_resched_lock(lock) ({ \
1591 ___might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);\
1592 __cond_resched_lock(lock); \
1595 extern int __cond_resched_softirq(void);
1597 #define cond_resched_softirq() ({ \
1598 ___might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET); \
1599 __cond_resched_softirq(); \
1602 static inline void cond_resched_rcu(void)
1604 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
1612 * Does a critical section need to be broken due to another
1613 * task waiting?: (technically does not depend on CONFIG_PREEMPT,
1614 * but a general need for low latency)
1616 static inline int spin_needbreak(spinlock_t *lock)
1618 #ifdef CONFIG_PREEMPT
1619 return spin_is_contended(lock);
1625 static __always_inline bool need_resched(void)
1627 return unlikely(tif_need_resched());
1631 * Wrappers for p->thread_info->cpu access. No-op on UP.
1635 static inline unsigned int task_cpu(const struct task_struct *p)
1637 #ifdef CONFIG_THREAD_INFO_IN_TASK
1640 return task_thread_info(p)->cpu;
1644 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
1648 static inline unsigned int task_cpu(const struct task_struct *p)
1653 static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
1657 #endif /* CONFIG_SMP */
1660 * In order to reduce various lock holder preemption latencies provide an
1661 * interface to see if a vCPU is currently running or not.
1663 * This allows us to terminate optimistic spin loops and block, analogous to
1664 * the native optimistic spin heuristic of testing if the lock owner task is
1667 #ifndef vcpu_is_preempted
1668 # define vcpu_is_preempted(cpu) false
1671 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
1672 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
1674 #ifndef TASK_SIZE_OF
1675 #define TASK_SIZE_OF(tsk) TASK_SIZE