| // Copyright 2020 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // This file records the static ranks of the locks in the runtime. If a lock |
| // is not given a rank, then it is assumed to be a leaf lock, which means no other |
| // lock can be acquired while it is held. Therefore, leaf locks do not need to be |
| // given an explicit rank. We list all of the architecture-independent leaf locks |
| // for documentation purposes, but don't list any of the architecture-dependent |
| // locks (which are all leaf locks). debugLock is ignored for ranking, since it is used |
| // when printing out lock ranking errors. |
| // |
| // lockInit(l *mutex, rank int) is used to set the rank of lock before it is used. |
| // If there is no clear place to initialize a lock, then the rank of a lock can be |
| // specified during the lock call itself via lockWithrank(l *mutex, rank int). |
| // |
| // Besides the static lock ranking (which is a total ordering of the locks), we |
| // also represent and enforce the actual partial order among the locks in the |
| // arcs[] array below. That is, if it is possible that lock B can be acquired when |
| // lock A is the previous acquired lock that is still held, then there should be |
| // an entry for A in arcs[B][]. We will currently fail not only if the total order |
| // (the lock ranking) is violated, but also if there is a missing entry in the |
| // partial order. |
| |
| package runtime |
| |
| type lockRank int |
| |
| // Constants representing the lock rank of the architecture-independent locks in |
| // the runtime. Locks with lower rank must be taken before locks with higher |
| // rank. |
| const ( |
| lockRankDummy lockRank = iota |
| |
| // Locks held above sched |
| lockRankSysmon |
| lockRankScavenge |
| lockRankForcegc |
| lockRankSweepWaiters |
| lockRankAssistQueue |
| lockRankCpuprof |
| lockRankSweep |
| |
| lockRankSched |
| lockRankDeadlock |
| lockRankPanic |
| lockRankAllg |
| lockRankAllp |
| lockRankPollDesc |
| |
| lockRankTimers // Multiple timers locked simultaneously in destroy() |
| lockRankItab |
| lockRankReflectOffs |
| lockRankHchan // Multiple hchans acquired in lock order in syncadjustsudogs() |
| lockRankFin |
| lockRankNotifyList |
| lockRankTraceBuf |
| lockRankTraceStrings |
| lockRankMspanSpecial |
| lockRankProf |
| lockRankGcBitsArenas |
| lockRankRoot |
| lockRankTrace |
| lockRankTraceStackTab |
| lockRankNetpollInit |
| |
| lockRankRwmutexW |
| lockRankRwmutexR |
| |
| lockRankSpanSetSpine |
| lockRankGscan |
| lockRankStackpool |
| lockRankStackLarge |
| lockRankDefer |
| lockRankSudog |
| |
| // Memory-related non-leaf locks |
| lockRankWbufSpans |
| lockRankMheap |
| lockRankMheapSpecial |
| |
| // Memory-related leaf locks |
| lockRankGlobalAlloc |
| |
| // Other leaf locks |
| lockRankGFree |
| // Generally, hchan must be acquired before gscan. But in one specific |
| // case (in syncadjustsudogs from markroot after the g has been suspended |
| // by suspendG), we allow gscan to be acquired, and then an hchan lock. To |
| // allow this case, we get this lockRankHchanLeaf rank in |
| // syncadjustsudogs(), rather than lockRankHchan. By using this special |
| // rank, we don't allow any further locks to be acquired other than more |
| // hchan locks. |
| lockRankHchanLeaf |
| |
| // Leaf locks with no dependencies, so these constants are not actually used anywhere. |
| // There are other architecture-dependent leaf locks as well. |
| lockRankNewmHandoff |
| lockRankDebugPtrmask |
| lockRankFaketimeState |
| lockRankTicks |
| lockRankRaceFini |
| lockRankPollCache |
| lockRankDebug |
| ) |
| |
| // lockRankLeafRank is the rank of lock that does not have a declared rank, and hence is |
| // a leaf lock. |
| const lockRankLeafRank lockRank = 1000 |
| |
| // lockNames gives the names associated with each of the above ranks |
| var lockNames = []string{ |
| lockRankDummy: "", |
| |
| lockRankSysmon: "sysmon", |
| lockRankScavenge: "scavenge", |
| lockRankForcegc: "forcegc", |
| lockRankSweepWaiters: "sweepWaiters", |
| lockRankAssistQueue: "assistQueue", |
| lockRankCpuprof: "cpuprof", |
| lockRankSweep: "sweep", |
| |
| lockRankSched: "sched", |
| lockRankDeadlock: "deadlock", |
| lockRankPanic: "panic", |
| lockRankAllg: "allg", |
| lockRankAllp: "allp", |
| lockRankPollDesc: "pollDesc", |
| |
| lockRankTimers: "timers", |
| lockRankItab: "itab", |
| lockRankReflectOffs: "reflectOffs", |
| |
| lockRankHchan: "hchan", |
| lockRankFin: "fin", |
| lockRankNotifyList: "notifyList", |
| lockRankTraceBuf: "traceBuf", |
| lockRankTraceStrings: "traceStrings", |
| lockRankMspanSpecial: "mspanSpecial", |
| lockRankProf: "prof", |
| lockRankGcBitsArenas: "gcBitsArenas", |
| lockRankRoot: "root", |
| lockRankTrace: "trace", |
| lockRankTraceStackTab: "traceStackTab", |
| lockRankNetpollInit: "netpollInit", |
| |
| lockRankRwmutexW: "rwmutexW", |
| lockRankRwmutexR: "rwmutexR", |
| |
| lockRankSpanSetSpine: "spanSetSpine", |
| lockRankGscan: "gscan", |
| lockRankStackpool: "stackpool", |
| lockRankStackLarge: "stackLarge", |
| lockRankDefer: "defer", |
| lockRankSudog: "sudog", |
| |
| lockRankWbufSpans: "wbufSpans", |
| lockRankMheap: "mheap", |
| lockRankMheapSpecial: "mheapSpecial", |
| |
| lockRankGlobalAlloc: "globalAlloc.mutex", |
| |
| lockRankGFree: "gFree", |
| lockRankHchanLeaf: "hchanLeaf", |
| |
| lockRankNewmHandoff: "newmHandoff.lock", |
| lockRankDebugPtrmask: "debugPtrmask.lock", |
| lockRankFaketimeState: "faketimeState.lock", |
| lockRankTicks: "ticks.lock", |
| lockRankRaceFini: "raceFiniLock", |
| lockRankPollCache: "pollCache.lock", |
| lockRankDebug: "debugLock", |
| } |
| |
| func (rank lockRank) String() string { |
| if rank == 0 { |
| return "UNKNOWN" |
| } |
| if rank == lockRankLeafRank { |
| return "LEAF" |
| } |
| return lockNames[rank] |
| } |
| |
| // lockPartialOrder is a partial order among the various lock types, listing the immediate |
| // ordering that has actually been observed in the runtime. Each entry (which |
| // corresponds to a particular lock rank) specifies the list of locks that can be |
| // already be held immediately "above" it. |
| // |
| // So, for example, the lockRankSched entry shows that all the locks preceding it in |
| // rank can actually be held. The fin lock shows that only the sched, timers, or |
| // hchan lock can be held immediately above it when it is acquired. |
| var lockPartialOrder [][]lockRank = [][]lockRank{ |
| lockRankDummy: {}, |
| lockRankSysmon: {}, |
| lockRankScavenge: {lockRankSysmon}, |
| lockRankForcegc: {lockRankSysmon}, |
| lockRankSweepWaiters: {}, |
| lockRankAssistQueue: {}, |
| lockRankCpuprof: {}, |
| lockRankSweep: {}, |
| lockRankSched: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep}, |
| lockRankDeadlock: {lockRankDeadlock}, |
| lockRankPanic: {lockRankDeadlock}, |
| lockRankAllg: {lockRankSysmon, lockRankSched, lockRankPanic}, |
| lockRankAllp: {lockRankSysmon, lockRankSched}, |
| lockRankPollDesc: {}, |
| lockRankTimers: {lockRankSysmon, lockRankScavenge, lockRankSched, lockRankAllp, lockRankPollDesc, lockRankTimers}, |
| lockRankItab: {}, |
| lockRankReflectOffs: {lockRankItab}, |
| lockRankHchan: {lockRankScavenge, lockRankSweep, lockRankHchan}, |
| lockRankFin: {lockRankSysmon, lockRankScavenge, lockRankSched, lockRankAllg, lockRankTimers, lockRankHchan}, |
| lockRankNotifyList: {}, |
| lockRankTraceBuf: {lockRankSysmon, lockRankScavenge}, |
| lockRankTraceStrings: {lockRankTraceBuf}, |
| lockRankMspanSpecial: {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings}, |
| lockRankProf: {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan}, |
| lockRankGcBitsArenas: {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan}, |
| lockRankRoot: {}, |
| lockRankTrace: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankAssistQueue, lockRankSched, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot, lockRankSweep}, |
| lockRankTraceStackTab: {lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankSched, lockRankAllg, lockRankTimers, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot, lockRankTrace}, |
| lockRankNetpollInit: {lockRankTimers}, |
| |
| lockRankRwmutexW: {}, |
| lockRankRwmutexR: {lockRankRwmutexW}, |
| |
| lockRankSpanSetSpine: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan}, |
| lockRankGscan: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot, lockRankNotifyList, lockRankProf, lockRankGcBitsArenas, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankSpanSetSpine}, |
| lockRankStackpool: {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankPollDesc, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankRwmutexR, lockRankSpanSetSpine, lockRankGscan}, |
| lockRankStackLarge: {lockRankSysmon, lockRankAssistQueue, lockRankSched, lockRankItab, lockRankHchan, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankSpanSetSpine, lockRankGscan}, |
| lockRankDefer: {}, |
| lockRankSudog: {lockRankNotifyList, lockRankHchan}, |
| lockRankWbufSpans: {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankSched, lockRankAllg, lockRankPollDesc, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceStrings, lockRankMspanSpecial, lockRankProf, lockRankRoot, lockRankGscan, lockRankDefer, lockRankSudog}, |
| lockRankMheap: {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankPollDesc, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan, lockRankMspanSpecial, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankDefer, lockRankSudog, lockRankWbufSpans, lockRankSpanSetSpine}, |
| lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan}, |
| lockRankGlobalAlloc: {lockRankProf, lockRankSpanSetSpine, lockRankMheap, lockRankMheapSpecial}, |
| |
| lockRankGFree: {lockRankSched}, |
| lockRankHchanLeaf: {lockRankGscan, lockRankHchanLeaf}, |
| |
| lockRankNewmHandoff: {}, |
| lockRankDebugPtrmask: {}, |
| lockRankFaketimeState: {}, |
| lockRankTicks: {}, |
| lockRankRaceFini: {}, |
| lockRankPollCache: {}, |
| lockRankDebug: {}, |
| } |
