Linux下的进程控制块——task_struct
在Linux中具体实现PCB的是 task_struct数据结构，以下实现摘自github
我想说它真的很长很长...... ↓
1 struct task_struct { 2 volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped *ruxia/ 3 void *stack; 4 atomic_t usage; 5 unsigned int flags; /* per process flags, defined below */ 6 unsigned int ptrace; 7 8 #ifdef CONFIG_SMP 9 struct llist_node wake_entry; 10 int on_cpu; 11 unsigned int wakee_flips; 12 unsigned long wakee_flip_decay_ts; 13 struct task_struct *last_wakee; 14 15 int wake_cpu; 16 #endif 17 int on_rq; 18 19 int prio, static_prio, normal_prio; 20 unsigned int rt_priority; 21 const struct sched_class *sched_class; 22 struct sched_entity se; 23 struct sched_rt_entity rt; 24 #ifdef CONFIG_CGROUP_SCHED 25 struct task_group *sched_task_group; 26 #endif 27 struct sched_dl_entity dl; 28 29 #ifdef CONFIG_PREEMPT_NOTIFIERS 30 /* list of struct preempt_notifier: */ 31 struct hlist_head preempt_notifiers; 32 #endif 33 34 #ifdef CONFIG_BLK_DEV_IO_TRACE 35 unsigned int btrace_seq; 36 #endif 37 38 unsigned int policy; 39 int nr_cpus_allowed; 40 cpumask_t cpus_allowed; 41 42 #ifdef CONFIG_PREEMPT_RCU 43 int rcu_read_lock_nesting; 44 union rcu_special rcu_read_unlock_special; 45 struct list_head rcu_node_entry; 46 struct rcu_node *rcu_blocked_node; 47 #endif /* #ifdef CONFIG_PREEMPT_RCU */ 48 #ifdef CONFIG_TASKS_RCU 49 unsigned long rcu_tasks_nvcsw; 50 bool rcu_tasks_holdout; 51 struct list_head rcu_tasks_holdout_list; 52 int rcu_tasks_idle_cpu; 53 #endif /* #ifdef CONFIG_TASKS_RCU */ 54 55 #ifdef CONFIG_SCHED_INFO 56 struct sched_info sched_info; 57 #endif 58 59 struct list_head tasks; 60 #ifdef CONFIG_SMP 61 struct plist_node pushable_tasks; 62 struct rb_node pushable_dl_tasks; 63 #endif 64 65 struct mm_struct *mm, *active_mm; 66 /* per-thread vma caching */ 67 u32 vmacache_seqnum; 68 struct vm_area_struct *vmacache[VMACACHE_SIZE]; 69 #if defined(SPLIT_RSS_COUNTING) 70 struct task_rss_stat rss_stat; 71 #endif 72 /* task state */ 73 int exit_state; 74 int exit_code, exit_signal; 75 int pdeath_signal; /* The signal sent when the parent dies */ 76 unsigned long jobctl; /* JOBCTL_*, siglock protected */ 77 78 /* Used for emulating ABI behavior of previous Linux versions */ 79 unsigned int personality; 80 81 /* scheduler bits, serialized by scheduler locks */ 82 unsigned sched_reset_on_fork:1; 83 unsigned sched_contributes_to_load:1; 84 unsigned sched_migrated:1; 85 unsigned sched_remote_wakeup:1; 86 unsigned :0; /* force alignment to the next boundary */ 87 88 /* unserialized, strictly 'current' */ 89 unsigned in_execve:1; /* bit to tell LSMs we're in execve */ 90 unsigned in_iowait:1; 91 #ifdef CONFIG_MEMCG 92 unsigned memcg_may_oom:1; 93 #ifndef CONFIG_SLOB 94 unsigned memcg_kmem_skip_account:1; 95 #endif 96 #endif 97 #ifdef CONFIG_COMPAT_BRK 98 unsigned brk_randomized:1; 99 #endif 100 101 unsigned long atomic_flags; /* Flags needing atomic access. */ 102 103 struct restart_block restart_block; 104 105 pid_t pid; 106 pid_t tgid; 107 108 #ifdef CONFIG_CC_STACKPROTECTOR 109 /* Canary value for the -fstack-protector gcc feature */ 110 unsigned long stack_canary; 111 #endif 112 /* 113 * pointers to (original) parent process, youngest child, younger sibling, 114 * older sibling, respectively. (p->father can be replaced with 115 * p->real_parent->pid) 116 */ 117 struct task_struct __rcu *real_parent; /* real parent process */ 118 struct task_struct __rcu *parent; /* recipient of SIGCHLD, wait4() reports */ 119 /* 120 * children/sibling forms the list of my natural children 121 */ 122 struct list_head children; /* list of my children */ 123 struct list_head sibling; /* linkage in my parent's children list */ 124 struct task_struct *group_leader; /* threadgroup leader */ 125 126 /* 127 * ptraced is the list of tasks this task is using ptrace on. 128 * This includes both natural children and PTRACE_ATTACH targets. 129 * p->ptrace_entry is p's link on the p->parent->ptraced list. 130 */ 131 struct list_head ptraced; 132 struct list_head ptrace_entry; 133 134 /* PID/PID hash table linkage. */ 135 struct pid_link pids[PIDTYPE_MAX]; 136 struct list_head thread_group; 137 struct list_head thread_node; 138 139 struct completion *vfork_done; /* for vfork() */ 140 int __user *set_child_tid; /* CLONE_CHILD_SETTID */ 141 int __user *clear_child_tid; /* CLONE_CHILD_CLEARTID */ 142 143 cputime_t utime, stime, utimescaled, stimescaled; 144 cputime_t gtime; 145 struct prev_cputime prev_cputime; 146 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN 147 seqcount_t vtime_seqcount; 148 unsigned long long vtime_snap; 149 enum { 150 /* Task is sleeping or running in a CPU with VTIME inactive */ 151 VTIME_INACTIVE = 0, 152 /* Task runs in userspace in a CPU with VTIME active */ 153 VTIME_USER, 154 /* Task runs in kernelspace in a CPU with VTIME active */ 155 VTIME_SYS, 156 } vtime_snap_whence; 157 #endif 158 159 #ifdef CONFIG_NO_HZ_FULL 160 atomic_t tick_dep_mask; 161 #endif 162 unsigned long nvcsw, nivcsw; /* context switch counts */ 163 u64 start_time; /* monotonic time in nsec */ 164 u64 real_start_time; /* boot based time in nsec */ 165 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */ 166 unsigned long min_flt, maj_flt; 167 168 struct task_cputime cputime_expires; 169 struct list_head cpu_timers[3]; 170 171 /* process credentials */ 172 const struct cred __rcu *real_cred; /* objective and real subjective task 173 * credentials (COW) */ 174 const struct cred __rcu *cred; /* effective (overridable) subjective task 175 * credentials (COW) */ 176 char comm[TASK_COMM_LEN]; /* executable name excluding path 177 - access with [gs]et_task_comm (which lock 178 it with task_lock()) 179 - initialized normally by setup_new_exec */ 180 /* file system info */ 181 struct nameidata *nameidata; 182 #ifdef CONFIG_SYSVIPC 183 /* ipc stuff */ 184 struct sysv_sem sysvsem; 185 struct sysv_shm sysvshm; 186 #endif 187 #ifdef CONFIG_DETECT_HUNG_TASK 188 /* hung task detection */ 189 unsigned long last_switch_count; 190 #endif 191 /* filesystem information */ 192 struct fs_struct *fs; 193 /* open file information */ 194 struct files_struct *files; 195 /* namespaces */ 196 struct nsproxy *nsproxy; 197 /* signal handlers */ 198 struct signal_struct *signal; 199 struct sighand_struct *sighand; 200 201 sigset_t blocked, real_blocked; 202 sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */ 203 struct sigpending pending; 204 205 unsigned long sas_ss_sp; 206 size_t sas_ss_size; 207 unsigned sas_ss_flags; 208 209 struct callback_head *task_works; 210 211 struct audit_context *audit_context; 212 #ifdef CONFIG_AUDITSYSCALL 213 kuid_t loginuid; 214 unsigned int sessionid; 215 #endif 216 struct seccomp seccomp; 217 218 /* Thread group tracking */ 219 u32 parent_exec_id; 220 u32 self_exec_id; 221 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed, 222 * mempolicy */ 223 spinlock_t alloc_lock; 224 225 /* Protection of the PI data structures: */ 226 raw_spinlock_t pi_lock; 227 228 struct wake_q_node wake_q; 229 230 #ifdef CONFIG_RT_MUTEXES 231 /* PI waiters blocked on a rt_mutex held by this task */ 232 struct rb_root pi_waiters; 233 struct rb_node *pi_waiters_leftmost; 234 /* Deadlock detection and priority inheritance handling */ 235 struct rt_mutex_waiter *pi_blocked_on; 236 #endif 237 238 #ifdef CONFIG_DEBUG_MUTEXES 239 /* mutex deadlock detection */ 240 struct mutex_waiter *blocked_on; 241 #endif 242 #ifdef CONFIG_TRACE_IRQFLAGS 243 unsigned int irq_events; 244 unsigned long hardirq_enable_ip; 245 unsigned long hardirq_disable_ip; 246 unsigned int hardirq_enable_event; 247 unsigned int hardirq_disable_event; 248 int hardirqs_enabled; 249 int hardirq_context; 250 unsigned long softirq_disable_ip; 251 unsigned long softirq_enable_ip; 252 unsigned int softirq_disable_event; 253 unsigned int softirq_enable_event; 254 int softirqs_enabled; 255 int softirq_context; 256 #endif 257 #ifdef CONFIG_LOCKDEP 258 # define MAX_LOCK_DEPTH 48UL 259 u64 curr_chain_key; 260 int lockdep_depth; 261 unsigned int lockdep_recursion; 262 struct held_lock held_locks[MAX_LOCK_DEPTH]; 263 gfp_t lockdep_reclaim_gfp; 264 #endif 265 #ifdef CONFIG_UBSAN 266 unsigned int in_ubsan; 267 #endif 268 269 /* journalling filesystem info */ 270 void *journal_info; 271 272 /* stacked block device info */ 273 struct bio_list *bio_list; 274 275 #ifdef CONFIG_BLOCK 276 /* stack plugging */ 277 struct blk_plug *plug; 278 #endif 279 280 /* VM state */ 281 struct reclaim_state *reclaim_state; 282 283 struct backing_dev_info *backing_dev_info; 284 285 struct io_context *io_context; 286 287 unsigned long ptrace_message; 288 siginfo_t *last_siginfo; /* For ptrace use. */ 289 struct task_io_accounting ioac; 290 #if defined(CONFIG_TASK_XACCT) 291 u64 acct_rss_mem1; /* accumulated rss usage */ 292 u64 acct_vm_mem1; /* accumulated virtual memory usage */ 293 cputime_t acct_timexpd; /* stime + utime since last update */ 294 #endif 295 #ifdef CONFIG_CPUSETS 296 nodemask_t mems_allowed; /* Protected by alloc_lock */ 297 seqcount_t mems_allowed_seq; /* Seqence no to catch updates */ 298 int cpuset_mem_spread_rotor; 299 int cpuset_slab_spread_rotor; 300 #endif 301 #ifdef CONFIG_CGROUPS 302 /* Control Group info protected by css_set_lock */ 303 struct css_set __rcu *cgroups; 304 /* cg_list protected by css_set_lock and tsk->alloc_lock */ 305 struct list_head cg_list; 306 #endif 307 #ifdef CONFIG_FUTEX 308 struct robust_list_head __user *robust_list; 309 #ifdef CONFIG_COMPAT 310 struct compat_robust_list_head __user *compat_robust_list; 311 #endif 312 struct list_head pi_state_list; 313 struct futex_pi_state *pi_state_cache; 314 #endif 315 #ifdef CONFIG_PERF_EVENTS 316 struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts]; 317 struct mutex perf_event_mutex; 318 struct list_head perf_event_list; 319 #endif 320 #ifdef CONFIG_DEBUG_PREEMPT 321 unsigned long preempt_disable_ip; 322 #endif 323 #ifdef CONFIG_NUMA 324 struct mempolicy *mempolicy; /* Protected by alloc_lock */ 325 short il_next; 326 short pref_node_fork; 327 #endif 328 #ifdef CONFIG_NUMA_BALANCING 329 int numa_scan_seq; 330 unsigned int numa_scan_period; 331 unsigned int numa_scan_period_max; 332 int numa_preferred_nid; 333 unsigned long numa_migrate_retry; 334 u64 node_stamp; /* migration stamp */ 335 u64 last_task_numa_placement; 336 u64 last_sum_exec_runtime; 337 struct callback_head numa_work; 338 339 struct list_head numa_entry; 340 struct numa_group *numa_group; 341 342 /* 343 * numa_faults is an array split into four regions: 344 * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer 345 * in this precise order. 346 * 347 * faults_memory: Exponential decaying average of faults on a per-node 348 * basis. Scheduling placement decisions are made based on these 349 * counts. The values remain static for the duration of a PTE scan. 350 * faults_cpu: Track the nodes the process was running on when a NUMA 351 * hinting fault was incurred. 352 * faults_memory_buffer and faults_cpu_buffer: Record faults per node 353 * during the current scan window. When the scan completes, the counts 354 * in faults_memory and faults_cpu decay and these values are copied. 355 */ 356 unsigned long *numa_faults; 357 unsigned long total_numa_faults; 358 359 /* 360 * numa_faults_locality tracks if faults recorded during the last 361 * scan window were remote/local or failed to migrate. The task scan 362 * period is adapted based on the locality of the faults with different 363 * weights depending on whether they were shared or private faults 364 */ 365 unsigned long numa_faults_locality[3]; 366 367 unsigned long numa_pages_migrated; 368 #endif /* CONFIG_NUMA_BALANCING */ 369 370 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 371 struct tlbflush_unmap_batch tlb_ubc; 372 #endif 373 374 struct rcu_head rcu; 375 376 /* 377 * cache last used pipe for splice 378 */ 379 struct pipe_inode_info *splice_pipe; 380 381 struct page_frag task_frag; 382 383 #ifdef CONFIG_TASK_DELAY_ACCT 384 struct task_delay_info *delays; 385 #endif 386 #ifdef CONFIG_FAULT_INJECTION 387 int make_it_fail; 388 #endif 389 /* 390 * when (nr_dirtied >= nr_dirtied_pause), it's time to call 391 * balance_dirty_pages() for some dirty throttling pause 392 */ 393 int nr_dirtied; 394 int nr_dirtied_pause; 395 unsigned long dirty_paused_when; /* start of a write-and-pause period */ 396 397 #ifdef CONFIG_LATENCYTOP 398 int latency_record_count; 399 struct latency_record latency_record[LT_SAVECOUNT]; 400 #endif 401 /* 402 * time slack values; these are used to round up poll() and 403 * select() etc timeout values. These are in nanoseconds. 404 */ 405 u64 timer_slack_ns; 406 u64 default_timer_slack_ns; 407 408 #ifdef CONFIG_KASAN 409 unsigned int kasan_depth; 410 #endif 411 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 412 /* Index of current stored address in ret_stack */ 413 int curr_ret_stack; 414 /* Stack of return addresses for return function tracing */ 415 struct ftrace_ret_stack *ret_stack; 416 /* time stamp for last schedule */ 417 unsigned long long ftrace_timestamp; 418 /* 419 * Number of functions that haven't been traced 420 * because of depth overrun. 421 */ 422 atomic_t trace_overrun; 423 /* Pause for the tracing */ 424 atomic_t tracing_graph_pause; 425 #endif 426 #ifdef CONFIG_TRACING 427 /* state flags for use by tracers */ 428 unsigned long trace; 429 /* bitmask and counter of trace recursion */ 430 unsigned long trace_recursion; 431 #endif /* CONFIG_TRACING */ 432 #ifdef CONFIG_KCOV 433 /* Coverage collection mode enabled for this task (0 if disabled). */ 434 enum kcov_mode kcov_mode; 435 /* Size of the kcov_area. */ 436 unsigned kcov_size; 437 /* Buffer for coverage collection. */ 438 void *kcov_area; 439 /* kcov desciptor wired with this task or NULL. */ 440 struct kcov *kcov; 441 #endif 442 #ifdef CONFIG_MEMCG 443 struct mem_cgroup *memcg_in_oom; 444 gfp_t memcg_oom_gfp_mask; 445 int memcg_oom_order; 446 447 /* number of pages to reclaim on returning to userland */ 448 unsigned int memcg_nr_pages_over_high; 449 #endif 450 #ifdef CONFIG_UPROBES 451 struct uprobe_task *utask; 452 #endif 453 #if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE) 454 unsigned int sequential_io; 455 unsigned int sequential_io_avg; 456 #endif 457 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP 458 unsigned long task_state_change; 459 #endif 460 int pagefault_disabled; 461 #ifdef CONFIG_MMU 462 struct task_struct *oom_reaper_list; 463 #endif 464 /* CPU-specific state of this task */ 465 struct thread_struct thread; 466 /* 467 * WARNING: on x86, 'thread_struct' contains a variable-sized 468 * structure. It *MUST* be at the end of 'task_struct'. 469 * 470 * Do not put anything below here! 471 */ 472 };
