github.com/zxy12/go_duplicate_112_new@v0.0.0-20200807091221-747231827200/src/runtime/runtime2.go (about) 1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime 6 7 import ( 8 "internal/cpu" 9 "runtime/internal/atomic" 10 "runtime/internal/sys" 11 "unsafe" 12 ) 13 14 // defined constants 15 const ( 16 // G status 17 // 18 // Beyond indicating the general state of a G, the G status 19 // acts like a lock on the goroutine's stack (and hence its 20 // ability to execute user code). 21 // 22 // If you add to this list, add to the list 23 // of "okay during garbage collection" status 24 // in mgcmark.go too. 25 26 // _Gidle means this goroutine was just allocated and has not 27 // yet been initialized. 28 _Gidle = iota // 0 29 30 // _Grunnable means this goroutine is on a run queue. It is 31 // not currently executing user code. The stack is not owned. 32 _Grunnable // 1 33 34 // _Grunning means this goroutine may execute user code. The 35 // stack is owned by this goroutine. It is not on a run queue. 36 // It is assigned an M and a P. 37 _Grunning // 2 38 39 // _Gsyscall means this goroutine is executing a system call. 40 // It is not executing user code. The stack is owned by this 41 // goroutine. It is not on a run queue. It is assigned an M. 42 _Gsyscall // 3 43 44 // _Gwaiting means this goroutine is blocked in the runtime. 45 // It is not executing user code. It is not on a run queue, 46 // but should be recorded somewhere (e.g., a channel wait 47 // queue) so it can be ready()d when necessary. The stack is 48 // not owned *except* that a channel operation may read or 49 // write parts of the stack under the appropriate channel 50 // lock. Otherwise, it is not safe to access the stack after a 51 // goroutine enters _Gwaiting (e.g., it may get moved). 52 _Gwaiting // 4 53 54 // _Gmoribund_unused is currently unused, but hardcoded in gdb 55 // scripts. 56 _Gmoribund_unused // 5 57 58 // _Gdead means this goroutine is currently unused. It may be 59 // just exited, on a free list, or just being initialized. It 60 // is not executing user code. It may or may not have a stack 61 // allocated. The G and its stack (if any) are owned by the M 62 // that is exiting the G or that obtained the G from the free 63 // list. 64 _Gdead // 6 65 66 // _Genqueue_unused is currently unused. 67 _Genqueue_unused // 7 68 69 // _Gcopystack means this goroutine's stack is being moved. It 70 // is not executing user code and is not on a run queue. The 71 // stack is owned by the goroutine that put it in _Gcopystack. 72 _Gcopystack // 8 73 74 // _Gscan combined with one of the above states other than 75 // _Grunning indicates that GC is scanning the stack. The 76 // goroutine is not executing user code and the stack is owned 77 // by the goroutine that set the _Gscan bit. 78 // 79 // _Gscanrunning is different: it is used to briefly block 80 // state transitions while GC signals the G to scan its own 81 // stack. This is otherwise like _Grunning. 82 // 83 // atomicstatus&~Gscan gives the state the goroutine will 84 // return to when the scan completes. 85 _Gscan = 0x1000 86 _Gscanrunnable = _Gscan + _Grunnable // 0x1001 87 _Gscanrunning = _Gscan + _Grunning // 0x1002 88 _Gscansyscall = _Gscan + _Gsyscall // 0x1003 89 _Gscanwaiting = _Gscan + _Gwaiting // 0x1004 90 ) 91 92 const ( 93 // P status 94 _Pidle = iota 95 _Prunning // Only this P is allowed to change from _Prunning. 96 _Psyscall 97 _Pgcstop 98 _Pdead 99 ) 100 101 // Mutual exclusion locks. In the uncontended case, 102 // as fast as spin locks (just a few user-level instructions), 103 // but on the contention path they sleep in the kernel. 104 // A zeroed Mutex is unlocked (no need to initialize each lock). 105 type mutex struct { 106 // Futex-based impl treats it as uint32 key, 107 // while sema-based impl as M* waitm. 108 // Used to be a union, but unions break precise GC. 109 key uintptr 110 } 111 112 // sleep and wakeup on one-time events. 113 // before any calls to notesleep or notewakeup, 114 // must call noteclear to initialize the Note. 115 // then, exactly one thread can call notesleep 116 // and exactly one thread can call notewakeup (once). 117 // once notewakeup has been called, the notesleep 118 // will return. future notesleep will return immediately. 119 // subsequent noteclear must be called only after 120 // previous notesleep has returned, e.g. it's disallowed 121 // to call noteclear straight after notewakeup. 122 // 123 // notetsleep is like notesleep but wakes up after 124 // a given number of nanoseconds even if the event 125 // has not yet happened. if a goroutine uses notetsleep to 126 // wake up early, it must wait to call noteclear until it 127 // can be sure that no other goroutine is calling 128 // notewakeup. 129 // 130 // notesleep/notetsleep are generally called on g0, 131 // notetsleepg is similar to notetsleep but is called on user g. 132 type note struct { 133 // Futex-based impl treats it as uint32 key, 134 // while sema-based impl as M* waitm. 135 // Used to be a union, but unions break precise GC. 136 key uintptr 137 } 138 139 type funcval struct { 140 fn uintptr 141 // variable-size, fn-specific data here 142 } 143 144 type iface struct { 145 tab *itab 146 data unsafe.Pointer 147 } 148 149 type eface struct { 150 _type *_type 151 data unsafe.Pointer 152 } 153 154 func efaceOf(ep *interface{}) *eface { 155 return (*eface)(unsafe.Pointer(ep)) 156 } 157 158 // The guintptr, muintptr, and puintptr are all used to bypass write barriers. 159 // It is particularly important to avoid write barriers when the current P has 160 // been released, because the GC thinks the world is stopped, and an 161 // unexpected write barrier would not be synchronized with the GC, 162 // which can lead to a half-executed write barrier that has marked the object 163 // but not queued it. If the GC skips the object and completes before the 164 // queuing can occur, it will incorrectly free the object. 165 // 166 // We tried using special assignment functions invoked only when not 167 // holding a running P, but then some updates to a particular memory 168 // word went through write barriers and some did not. This breaks the 169 // write barrier shadow checking mode, and it is also scary: better to have 170 // a word that is completely ignored by the GC than to have one for which 171 // only a few updates are ignored. 172 // 173 // Gs and Ps are always reachable via true pointers in the 174 // allgs and allp lists or (during allocation before they reach those lists) 175 // from stack variables. 176 // 177 // Ms are always reachable via true pointers either from allm or 178 // freem. Unlike Gs and Ps we do free Ms, so it's important that 179 // nothing ever hold an muintptr across a safe point. 180 181 // A guintptr holds a goroutine pointer, but typed as a uintptr 182 // to bypass write barriers. It is used in the Gobuf goroutine state 183 // and in scheduling lists that are manipulated without a P. 184 // 185 // The Gobuf.g goroutine pointer is almost always updated by assembly code. 186 // In one of the few places it is updated by Go code - func save - it must be 187 // treated as a uintptr to avoid a write barrier being emitted at a bad time. 188 // Instead of figuring out how to emit the write barriers missing in the 189 // assembly manipulation, we change the type of the field to uintptr, 190 // so that it does not require write barriers at all. 191 // 192 // Goroutine structs are published in the allg list and never freed. 193 // That will keep the goroutine structs from being collected. 194 // There is never a time that Gobuf.g's contain the only references 195 // to a goroutine: the publishing of the goroutine in allg comes first. 196 // Goroutine pointers are also kept in non-GC-visible places like TLS, 197 // so I can't see them ever moving. If we did want to start moving data 198 // in the GC, we'd need to allocate the goroutine structs from an 199 // alternate arena. Using guintptr doesn't make that problem any worse. 200 type guintptr uintptr 201 202 //go:nosplit 203 func (gp guintptr) ptr() *g { return (*g)(unsafe.Pointer(gp)) } 204 205 //go:nosplit 206 func (gp *guintptr) set(g *g) { *gp = guintptr(unsafe.Pointer(g)) } 207 208 //go:nosplit 209 func (gp *guintptr) cas(old, new guintptr) bool { 210 return atomic.Casuintptr((*uintptr)(unsafe.Pointer(gp)), uintptr(old), uintptr(new)) 211 } 212 213 // setGNoWB performs *gp = new without a write barrier. 214 // For times when it's impractical to use a guintptr. 215 //go:nosplit 216 //go:nowritebarrier 217 func setGNoWB(gp **g, new *g) { 218 (*guintptr)(unsafe.Pointer(gp)).set(new) 219 } 220 221 type puintptr uintptr 222 223 //go:nosplit 224 func (pp puintptr) ptr() *p { return (*p)(unsafe.Pointer(pp)) } 225 226 //go:nosplit 227 func (pp *puintptr) set(p *p) { *pp = puintptr(unsafe.Pointer(p)) } 228 229 // muintptr is a *m that is not tracked by the garbage collector. 230 // 231 // Because we do free Ms, there are some additional constrains on 232 // muintptrs: 233 // 234 // 1. Never hold an muintptr locally across a safe point. 235 // 236 // 2. Any muintptr in the heap must be owned by the M itself so it can 237 // ensure it is not in use when the last true *m is released. 238 type muintptr uintptr 239 240 //go:nosplit 241 func (mp muintptr) ptr() *m { return (*m)(unsafe.Pointer(mp)) } 242 243 //go:nosplit 244 func (mp *muintptr) set(m *m) { *mp = muintptr(unsafe.Pointer(m)) } 245 246 // setMNoWB performs *mp = new without a write barrier. 247 // For times when it's impractical to use an muintptr. 248 //go:nosplit 249 //go:nowritebarrier 250 func setMNoWB(mp **m, new *m) { 251 (*muintptr)(unsafe.Pointer(mp)).set(new) 252 } 253 254 type gobuf struct { 255 // The offsets of sp, pc, and g are known to (hard-coded in) libmach. 256 // 257 // ctxt is unusual with respect to GC: it may be a 258 // heap-allocated funcval, so GC needs to track it, but it 259 // needs to be set and cleared from assembly, where it's 260 // difficult to have write barriers. However, ctxt is really a 261 // saved, live register, and we only ever exchange it between 262 // the real register and the gobuf. Hence, we treat it as a 263 // root during stack scanning, which means assembly that saves 264 // and restores it doesn't need write barriers. It's still 265 // typed as a pointer so that any other writes from Go get 266 // write barriers. 267 sp uintptr 268 pc uintptr 269 g guintptr 270 ctxt unsafe.Pointer 271 ret sys.Uintreg 272 lr uintptr 273 bp uintptr // for GOEXPERIMENT=framepointer 274 } 275 276 // sudog represents a g in a wait list, such as for sending/receiving 277 // on a channel. 278 // 279 // sudog is necessary because the g ↔ synchronization object relation 280 // is many-to-many. A g can be on many wait lists, so there may be 281 // many sudogs for one g; and many gs may be waiting on the same 282 // synchronization object, so there may be many sudogs for one object. 283 // 284 // sudogs are allocated from a special pool. Use acquireSudog and 285 // releaseSudog to allocate and free them. 286 type sudog struct { 287 // The following fields are protected by the hchan.lock of the 288 // channel this sudog is blocking on. shrinkstack depends on 289 // this for sudogs involved in channel ops. 290 291 g *g 292 293 // isSelect indicates g is participating in a select, so 294 // g.selectDone must be CAS'd to win the wake-up race. 295 isSelect bool 296 next *sudog 297 prev *sudog 298 elem unsafe.Pointer // data element (may point to stack) 299 300 // The following fields are never accessed concurrently. 301 // For channels, waitlink is only accessed by g. 302 // For semaphores, all fields (including the ones above) 303 // are only accessed when holding a semaRoot lock. 304 305 acquiretime int64 306 releasetime int64 307 ticket uint32 308 parent *sudog // semaRoot binary tree 309 waitlink *sudog // g.waiting list or semaRoot 310 waittail *sudog // semaRoot 311 c *hchan // channel 312 } 313 314 type libcall struct { 315 fn uintptr 316 n uintptr // number of parameters 317 args uintptr // parameters 318 r1 uintptr // return values 319 r2 uintptr 320 err uintptr // error number 321 } 322 323 // describes how to handle callback 324 type wincallbackcontext struct { 325 gobody unsafe.Pointer // go function to call 326 argsize uintptr // callback arguments size (in bytes) 327 restorestack uintptr // adjust stack on return by (in bytes) (386 only) 328 cleanstack bool 329 } 330 331 // Stack describes a Go execution stack. 332 // The bounds of the stack are exactly [lo, hi), 333 // with no implicit data structures on either side. 334 type stack struct { 335 lo uintptr 336 hi uintptr 337 } 338 339 type g struct { 340 // Stack parameters. 341 // stack describes the actual stack memory: [stack.lo, stack.hi). 342 // stackguard0 is the stack pointer compared in the Go stack growth prologue. 343 // It is stack.lo+StackGuard normally, but can be StackPreempt to trigger a preemption. 344 // stackguard1 is the stack pointer compared in the C stack growth prologue. 345 // It is stack.lo+StackGuard on g0 and gsignal stacks. 346 // It is ~0 on other goroutine stacks, to trigger a call to morestackc (and crash). 347 stack stack // offset known to runtime/cgo 348 stackguard0 uintptr // offset known to liblink 349 stackguard1 uintptr // offset known to liblink 350 351 _panic *_panic // innermost panic - offset known to liblink 352 _defer *_defer // innermost defer 353 m *m // current m; offset known to arm liblink 354 sched gobuf 355 syscallsp uintptr // if status==Gsyscall, syscallsp = sched.sp to use during gc 356 syscallpc uintptr // if status==Gsyscall, syscallpc = sched.pc to use during gc 357 stktopsp uintptr // expected sp at top of stack, to check in traceback 358 param unsafe.Pointer // passed parameter on wakeup 359 atomicstatus uint32 360 stackLock uint32 // sigprof/scang lock; TODO: fold in to atomicstatus 361 goid int64 362 schedlink guintptr 363 waitsince int64 // approx time when the g become blocked 364 waitreason waitReason // if status==Gwaiting 365 preempt bool // preemption signal, duplicates stackguard0 = stackpreempt 366 paniconfault bool // panic (instead of crash) on unexpected fault address 367 preemptscan bool // preempted g does scan for gc 368 gcscandone bool // g has scanned stack; protected by _Gscan bit in status 369 gcscanvalid bool // false at start of gc cycle, true if G has not run since last scan; TODO: remove? 370 throwsplit bool // must not split stack 371 raceignore int8 // ignore race detection events 372 sysblocktraced bool // StartTrace has emitted EvGoInSyscall about this goroutine 373 sysexitticks int64 // cputicks when syscall has returned (for tracing) 374 traceseq uint64 // trace event sequencer 375 tracelastp puintptr // last P emitted an event for this goroutine 376 lockedm muintptr 377 sig uint32 378 writebuf []byte 379 sigcode0 uintptr 380 sigcode1 uintptr 381 sigpc uintptr 382 gopc uintptr // pc of go statement that created this goroutine 383 ancestors *[]ancestorInfo // ancestor information goroutine(s) that created this goroutine (only used if debug.tracebackancestors) 384 startpc uintptr // pc of goroutine function 385 racectx uintptr 386 waiting *sudog // sudog structures this g is waiting on (that have a valid elem ptr); in lock order 387 cgoCtxt []uintptr // cgo traceback context 388 labels unsafe.Pointer // profiler labels 389 timer *timer // cached timer for time.Sleep 390 selectDone uint32 // are we participating in a select and did someone win the race? 391 392 // Per-G GC state 393 394 // gcAssistBytes is this G's GC assist credit in terms of 395 // bytes allocated. If this is positive, then the G has credit 396 // to allocate gcAssistBytes bytes without assisting. If this 397 // is negative, then the G must correct this by performing 398 // scan work. We track this in bytes to make it fast to update 399 // and check for debt in the malloc hot path. The assist ratio 400 // determines how this corresponds to scan work debt. 401 gcAssistBytes int64 402 } 403 404 type m struct { 405 g0 *g // goroutine with scheduling stack 406 morebuf gobuf // gobuf arg to morestack 407 divmod uint32 // div/mod denominator for arm - known to liblink 408 409 // Fields not known to debuggers. 410 procid uint64 // for debuggers, but offset not hard-coded 411 gsignal *g // signal-handling g 412 goSigStack gsignalStack // Go-allocated signal handling stack 413 sigmask sigset // storage for saved signal mask 414 tls [6]uintptr // thread-local storage (for x86 extern register) 415 mstartfn func() 416 curg *g // current running goroutine 417 caughtsig guintptr // goroutine running during fatal signal 418 p puintptr // attached p for executing go code (nil if not executing go code) 419 nextp puintptr 420 oldp puintptr // the p that was attached before executing a syscall 421 id int64 422 mallocing int32 423 throwing int32 424 preemptoff string // if != "", keep curg running on this m 425 locks int32 426 dying int32 427 profilehz int32 428 spinning bool // m is out of work and is actively looking for work 429 blocked bool // m is blocked on a note 430 inwb bool // m is executing a write barrier 431 newSigstack bool // minit on C thread called sigaltstack 432 printlock int8 433 incgo bool // m is executing a cgo call 434 freeWait uint32 // if == 0, safe to free g0 and delete m (atomic) 435 fastrand [2]uint32 436 needextram bool 437 traceback uint8 438 ncgocall uint64 // number of cgo calls in total 439 ncgo int32 // number of cgo calls currently in progress 440 cgoCallersUse uint32 // if non-zero, cgoCallers in use temporarily 441 cgoCallers *cgoCallers // cgo traceback if crashing in cgo call 442 park note 443 alllink *m // on allm 444 schedlink muintptr 445 mcache *mcache 446 lockedg guintptr 447 createstack [32]uintptr // stack that created this thread. 448 lockedExt uint32 // tracking for external LockOSThread 449 lockedInt uint32 // tracking for internal lockOSThread 450 nextwaitm muintptr // next m waiting for lock 451 waitunlockf unsafe.Pointer // todo go func(*g, unsafe.pointer) bool 452 waitlock unsafe.Pointer 453 waittraceev byte 454 waittraceskip int 455 startingtrace bool 456 syscalltick uint32 457 thread uintptr // thread handle 458 freelink *m // on sched.freem 459 460 // these are here because they are too large to be on the stack 461 // of low-level NOSPLIT functions. 462 libcall libcall 463 libcallpc uintptr // for cpu profiler 464 libcallsp uintptr 465 libcallg guintptr 466 syscall libcall // stores syscall parameters on windows 467 468 vdsoSP uintptr // SP for traceback while in VDSO call (0 if not in call) 469 vdsoPC uintptr // PC for traceback while in VDSO call 470 471 mOS 472 } 473 474 type p struct { 475 lock mutex 476 477 id int32 478 status uint32 // one of pidle/prunning/... 479 link puintptr 480 schedtick uint32 // incremented on every scheduler call 481 syscalltick uint32 // incremented on every system call 482 sysmontick sysmontick // last tick observed by sysmon 483 m muintptr // back-link to associated m (nil if idle) 484 mcache *mcache 485 racectx uintptr 486 487 deferpool [5][]*_defer // pool of available defer structs of different sizes (see panic.go) 488 deferpoolbuf [5][32]*_defer 489 490 // Cache of goroutine ids, amortizes accesses to runtime·sched.goidgen. 491 goidcache uint64 492 goidcacheend uint64 493 494 // Queue of runnable goroutines. Accessed without lock. 495 runqhead uint32 496 runqtail uint32 497 runq [256]guintptr 498 // runnext, if non-nil, is a runnable G that was ready'd by 499 // the current G and should be run next instead of what's in 500 // runq if there's time remaining in the running G's time 501 // slice. It will inherit the time left in the current time 502 // slice. If a set of goroutines is locked in a 503 // communicate-and-wait pattern, this schedules that set as a 504 // unit and eliminates the (potentially large) scheduling 505 // latency that otherwise arises from adding the ready'd 506 // goroutines to the end of the run queue. 507 runnext guintptr 508 509 // Available G's (status == Gdead) 510 gFree struct { 511 gList 512 n int32 513 } 514 515 sudogcache []*sudog 516 sudogbuf [128]*sudog 517 518 tracebuf traceBufPtr 519 520 // traceSweep indicates the sweep events should be traced. 521 // This is used to defer the sweep start event until a span 522 // has actually been swept. 523 traceSweep bool 524 // traceSwept and traceReclaimed track the number of bytes 525 // swept and reclaimed by sweeping in the current sweep loop. 526 traceSwept, traceReclaimed uintptr 527 528 palloc persistentAlloc // per-P to avoid mutex 529 530 // Per-P GC state 531 gcAssistTime int64 // Nanoseconds in assistAlloc 532 gcFractionalMarkTime int64 // Nanoseconds in fractional mark worker 533 gcBgMarkWorker guintptr 534 gcMarkWorkerMode gcMarkWorkerMode 535 536 // gcMarkWorkerStartTime is the nanotime() at which this mark 537 // worker started. 538 gcMarkWorkerStartTime int64 539 540 // gcw is this P's GC work buffer cache. The work buffer is 541 // filled by write barriers, drained by mutator assists, and 542 // disposed on certain GC state transitions. 543 gcw gcWork 544 545 // wbBuf is this P's GC write barrier buffer. 546 // 547 // TODO: Consider caching this in the running G. 548 wbBuf wbBuf 549 550 runSafePointFn uint32 // if 1, run sched.safePointFn at next safe point 551 552 pad cpu.CacheLinePad 553 } 554 555 type schedt struct { 556 // accessed atomically. keep at top to ensure alignment on 32-bit systems. 557 goidgen uint64 558 lastpoll uint64 559 560 lock mutex 561 562 // When increasing nmidle, nmidlelocked, nmsys, or nmfreed, be 563 // sure to call checkdead(). 564 565 midle muintptr // idle m's waiting for work 566 nmidle int32 // number of idle m's waiting for work 567 nmidlelocked int32 // number of locked m's waiting for work 568 mnext int64 // number of m's that have been created and next M ID 569 maxmcount int32 // maximum number of m's allowed (or die) 570 nmsys int32 // number of system m's not counted for deadlock 571 nmfreed int64 // cumulative number of freed m's 572 573 ngsys uint32 // number of system goroutines; updated atomically 574 575 pidle puintptr // idle p's 576 npidle uint32 577 nmspinning uint32 // See "Worker thread parking/unparking" comment in proc.go. 578 579 // Global runnable queue. 580 runq gQueue 581 runqsize int32 582 583 // disable controls selective disabling of the scheduler. 584 // 585 // Use schedEnableUser to control this. 586 // 587 // disable is protected by sched.lock. 588 disable struct { 589 // user disables scheduling of user goroutines. 590 user bool 591 runnable gQueue // pending runnable Gs 592 n int32 // length of runnable 593 } 594 595 // Global cache of dead G's. 596 gFree struct { 597 lock mutex 598 stack gList // Gs with stacks 599 noStack gList // Gs without stacks 600 n int32 601 } 602 603 // Central cache of sudog structs. 604 sudoglock mutex 605 sudogcache *sudog 606 607 // Central pool of available defer structs of different sizes. 608 deferlock mutex 609 deferpool [5]*_defer 610 611 // freem is the list of m's waiting to be freed when their 612 // m.exited is set. Linked through m.freelink. 613 freem *m 614 615 gcwaiting uint32 // gc is waiting to run 616 stopwait int32 617 stopnote note 618 sysmonwait uint32 619 sysmonnote note 620 621 // safepointFn should be called on each P at the next GC 622 // safepoint if p.runSafePointFn is set. 623 safePointFn func(*p) 624 safePointWait int32 625 safePointNote note 626 627 profilehz int32 // cpu profiling rate 628 629 procresizetime int64 // nanotime() of last change to gomaxprocs 630 totaltime int64 // ∫gomaxprocs dt up to procresizetime 631 } 632 633 // Values for the flags field of a sigTabT. 634 const ( 635 _SigNotify = 1 << iota // let signal.Notify have signal, even if from kernel 636 _SigKill // if signal.Notify doesn't take it, exit quietly 637 _SigThrow // if signal.Notify doesn't take it, exit loudly 638 _SigPanic // if the signal is from the kernel, panic 639 _SigDefault // if the signal isn't explicitly requested, don't monitor it 640 _SigGoExit // cause all runtime procs to exit (only used on Plan 9). 641 _SigSetStack // add SA_ONSTACK to libc handler 642 _SigUnblock // always unblock; see blockableSig 643 _SigIgn // _SIG_DFL action is to ignore the signal 644 ) 645 646 // Layout of in-memory per-function information prepared by linker 647 // See https://golang.org/s/go12symtab. 648 // Keep in sync with linker (../cmd/link/internal/ld/pcln.go:/pclntab) 649 // and with package debug/gosym and with symtab.go in package runtime. 650 type _func struct { 651 entry uintptr // start pc 652 nameoff int32 // function name 653 654 args int32 // in/out args size 655 deferreturn uint32 // offset of a deferreturn block from entry, if any. 656 657 pcsp int32 658 pcfile int32 659 pcln int32 660 npcdata int32 661 funcID funcID // set for certain special runtime functions 662 _ [2]int8 // unused 663 nfuncdata uint8 // must be last 664 } 665 666 // Pseudo-Func that is returned for PCs that occur in inlined code. 667 // A *Func can be either a *_func or a *funcinl, and they are distinguished 668 // by the first uintptr. 669 type funcinl struct { 670 zero uintptr // set to 0 to distinguish from _func 671 entry uintptr // entry of the real (the "outermost") frame. 672 name string 673 file string 674 line int 675 } 676 677 // layout of Itab known to compilers 678 // allocated in non-garbage-collected memory 679 // Needs to be in sync with 680 // ../cmd/compile/internal/gc/reflect.go:/^func.dumptypestructs. 681 type itab struct { 682 inter *interfacetype 683 _type *_type 684 hash uint32 // copy of _type.hash. Used for type switches. 685 _ [4]byte 686 fun [1]uintptr // variable sized. fun[0]==0 means _type does not implement inter. 687 } 688 689 // Lock-free stack node. 690 // // Also known to export_test.go. 691 type lfnode struct { 692 next uint64 693 pushcnt uintptr 694 } 695 696 type forcegcstate struct { 697 lock mutex 698 g *g 699 idle uint32 700 } 701 702 // startup_random_data holds random bytes initialized at startup. These come from 703 // the ELF AT_RANDOM auxiliary vector (vdso_linux_amd64.go or os_linux_386.go). 704 var startupRandomData []byte 705 706 // extendRandom extends the random numbers in r[:n] to the whole slice r. 707 // Treats n<0 as n==0. 708 func extendRandom(r []byte, n int) { 709 if n < 0 { 710 n = 0 711 } 712 for n < len(r) { 713 // Extend random bits using hash function & time seed 714 w := n 715 if w > 16 { 716 w = 16 717 } 718 h := memhash(unsafe.Pointer(&r[n-w]), uintptr(nanotime()), uintptr(w)) 719 for i := 0; i < sys.PtrSize && n < len(r); i++ { 720 r[n] = byte(h) 721 n++ 722 h >>= 8 723 } 724 } 725 } 726 727 // A _defer holds an entry on the list of deferred calls. 728 // If you add a field here, add code to clear it in freedefer. 729 type _defer struct { 730 siz int32 731 started bool 732 sp uintptr // sp at time of defer 733 pc uintptr 734 fn *funcval 735 _panic *_panic // panic that is running defer 736 link *_defer 737 } 738 739 // A _panic holds information about an active panic. 740 // 741 // This is marked go:notinheap because _panic values must only ever 742 // live on the stack. 743 // 744 // The argp and link fields are stack pointers, but don't need special 745 // handling during stack growth: because they are pointer-typed and 746 // _panic values only live on the stack, regular stack pointer 747 // adjustment takes care of them. 748 // 749 //go:notinheap 750 type _panic struct { 751 argp unsafe.Pointer // pointer to arguments of deferred call run during panic; cannot move - known to liblink 752 arg interface{} // argument to panic 753 link *_panic // link to earlier panic 754 recovered bool // whether this panic is over 755 aborted bool // the panic was aborted 756 } 757 758 // stack traces 759 type stkframe struct { 760 fn funcInfo // function being run 761 pc uintptr // program counter within fn 762 continpc uintptr // program counter where execution can continue, or 0 if not 763 lr uintptr // program counter at caller aka link register 764 sp uintptr // stack pointer at pc 765 fp uintptr // stack pointer at caller aka frame pointer 766 varp uintptr // top of local variables 767 argp uintptr // pointer to function arguments 768 arglen uintptr // number of bytes at argp 769 argmap *bitvector // force use of this argmap 770 } 771 772 // ancestorInfo records details of where a goroutine was started. 773 type ancestorInfo struct { 774 pcs []uintptr // pcs from the stack of this goroutine 775 goid int64 // goroutine id of this goroutine; original goroutine possibly dead 776 gopc uintptr // pc of go statement that created this goroutine 777 } 778 779 const ( 780 _TraceRuntimeFrames = 1 << iota // include frames for internal runtime functions. 781 _TraceTrap // the initial PC, SP are from a trap, not a return PC from a call 782 _TraceJumpStack // if traceback is on a systemstack, resume trace at g that called into it 783 ) 784 785 // The maximum number of frames we print for a traceback 786 const _TracebackMaxFrames = 100 787 788 // A waitReason explains why a goroutine has been stopped. 789 // See gopark. Do not re-use waitReasons, add new ones. 790 type waitReason uint8 791 792 const ( 793 waitReasonZero waitReason = iota // "" 794 waitReasonGCAssistMarking // "GC assist marking" 795 waitReasonIOWait // "IO wait" 796 waitReasonChanReceiveNilChan // "chan receive (nil chan)" 797 waitReasonChanSendNilChan // "chan send (nil chan)" 798 waitReasonDumpingHeap // "dumping heap" 799 waitReasonGarbageCollection // "garbage collection" 800 waitReasonGarbageCollectionScan // "garbage collection scan" 801 waitReasonPanicWait // "panicwait" 802 waitReasonSelect // "select" 803 waitReasonSelectNoCases // "select (no cases)" 804 waitReasonGCAssistWait // "GC assist wait" 805 waitReasonGCSweepWait // "GC sweep wait" 806 waitReasonChanReceive // "chan receive" 807 waitReasonChanSend // "chan send" 808 waitReasonFinalizerWait // "finalizer wait" 809 waitReasonForceGGIdle // "force gc (idle)" 810 waitReasonSemacquire // "semacquire" 811 waitReasonSleep // "sleep" 812 waitReasonSyncCondWait // "sync.Cond.Wait" 813 waitReasonTimerGoroutineIdle // "timer goroutine (idle)" 814 waitReasonTraceReaderBlocked // "trace reader (blocked)" 815 waitReasonWaitForGCCycle // "wait for GC cycle" 816 waitReasonGCWorkerIdle // "GC worker (idle)" 817 ) 818 819 var waitReasonStrings = [...]string{ 820 waitReasonZero: "", 821 waitReasonGCAssistMarking: "GC assist marking", 822 waitReasonIOWait: "IO wait", 823 waitReasonChanReceiveNilChan: "chan receive (nil chan)", 824 waitReasonChanSendNilChan: "chan send (nil chan)", 825 waitReasonDumpingHeap: "dumping heap", 826 waitReasonGarbageCollection: "garbage collection", 827 waitReasonGarbageCollectionScan: "garbage collection scan", 828 waitReasonPanicWait: "panicwait", 829 waitReasonSelect: "select", 830 waitReasonSelectNoCases: "select (no cases)", 831 waitReasonGCAssistWait: "GC assist wait", 832 waitReasonGCSweepWait: "GC sweep wait", 833 waitReasonChanReceive: "chan receive", 834 waitReasonChanSend: "chan send", 835 waitReasonFinalizerWait: "finalizer wait", 836 waitReasonForceGGIdle: "force gc (idle)", 837 waitReasonSemacquire: "semacquire", 838 waitReasonSleep: "sleep", 839 waitReasonSyncCondWait: "sync.Cond.Wait", 840 waitReasonTimerGoroutineIdle: "timer goroutine (idle)", 841 waitReasonTraceReaderBlocked: "trace reader (blocked)", 842 waitReasonWaitForGCCycle: "wait for GC cycle", 843 waitReasonGCWorkerIdle: "GC worker (idle)", 844 } 845 846 func (w waitReason) String() string { 847 if w < 0 || w >= waitReason(len(waitReasonStrings)) { 848 return "unknown wait reason" 849 } 850 return waitReasonStrings[w] 851 } 852 853 var ( 854 allglen uintptr 855 allm *m 856 allp []*p // len(allp) == gomaxprocs; may change at safe points, otherwise immutable 857 allpLock mutex // Protects P-less reads of allp and all writes 858 gomaxprocs int32 859 ncpu int32 860 forcegc forcegcstate 861 sched schedt 862 newprocs int32 863 864 // Information about what cpu features are available. 865 // Packages outside the runtime should not use these 866 // as they are not an external api. 867 // Set on startup in asm_{386,amd64,amd64p32}.s 868 processorVersionInfo uint32 869 isIntel bool 870 lfenceBeforeRdtsc bool 871 872 goarm uint8 // set by cmd/link on arm systems 873 framepointer_enabled bool // set by cmd/link 874 ) 875 876 // Set by the linker so the runtime can determine the buildmode. 877 var ( 878 islibrary bool // -buildmode=c-shared 879 isarchive bool // -buildmode=c-archive 880 )