runtime: make the lock rank DAG make more sense

This groups, comments, and generally reorganizes the lock rank graph
description by subsystem. It also introduces several pseudo-nodes that
more cleanly describe the inherent layering of lock ranks by
subsystem.

I believe this doesn't actually change the graph, but haven't verified
this.

For #53789.

Change-Id: I72f332f5a23b8217c7dc1b21411631ad48cee4b0
Reviewed-on: https://go-review.googlesource.com/c/go/+/418718
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>

diff --git a/src/runtime/lockrank.go b/src/runtime/lockrank.go
index 21c65233e3afbffc2f4455e4cfdb3e0f8aba4b25..83d1ac3f0b9b504060c5728bbe9c6613c5c1e312 100644 (file)
--- a/src/runtime/lockrank.go
+++ b/src/runtime/lockrank.go
@@ -12,48 +12,54 @@ const (
        lockRankUnknown lockRank = iota
 
        lockRankSysmon
+       lockRankScavenge
+       lockRankForcegc
+       lockRankDefer
        lockRankSweepWaiters
        lockRankAssistQueue
-       lockRankCpuprof
        lockRankSweep
        lockRankPollDesc
-       lockRankDeadlock
-       lockRankItab
-       lockRankNotifyList
-       lockRankRoot
-       lockRankRwmutexW
-       lockRankDefer
-       lockRankScavenge
-       lockRankForcegc
+       lockRankCpuprof
        lockRankSched
        lockRankAllg
        lockRankAllp
        lockRankTimers
-       lockRankReflectOffs
+       lockRankNetpollInit
        lockRankHchan
+       lockRankNotifyList
+       lockRankSudog
+       lockRankRwmutexW
+       lockRankRwmutexR
+       lockRankRoot
+       lockRankItab
+       lockRankReflectOffs
+       // TRACEGLOBAL
        lockRankTraceBuf
        lockRankTraceStrings
+       // MALLOC
+       lockRankFin
+       lockRankGcBitsArenas
+       lockRankMheapSpecial
        lockRankMspanSpecial
+       lockRankSpanSetSpine
+       // MPROF
        lockRankProfInsert
        lockRankProfBlock
        lockRankProfMemActive
-       lockRankGcBitsArenas
-       lockRankSpanSetSpine
-       lockRankMheapSpecial
-       lockRankFin
        lockRankProfMemFuture
+       // TRACE
        lockRankTrace
        lockRankTraceStackTab
-       lockRankNetpollInit
-       lockRankRwmutexR
+       // STACKGROW
        lockRankGscan
        lockRankStackpool
        lockRankStackLarge
        lockRankHchanLeaf
-       lockRankSudog
+       // WB
        lockRankWbufSpans
        lockRankMheap
        lockRankGlobalAlloc
+       lockRankDeadlock
        lockRankPanic
 )
 
@@ -64,48 +70,48 @@ const lockRankLeafRank lockRank = 1000
 // lockNames gives the names associated with each of the above ranks.
 var lockNames = []string{
        lockRankSysmon:        "sysmon",
+       lockRankScavenge:      "scavenge",
+       lockRankForcegc:       "forcegc",
+       lockRankDefer:         "defer",
        lockRankSweepWaiters:  "sweepWaiters",
        lockRankAssistQueue:   "assistQueue",
-       lockRankCpuprof:       "cpuprof",
        lockRankSweep:         "sweep",
        lockRankPollDesc:      "pollDesc",
-       lockRankDeadlock:      "deadlock",
-       lockRankItab:          "itab",
-       lockRankNotifyList:    "notifyList",
-       lockRankRoot:          "root",
-       lockRankRwmutexW:      "rwmutexW",
-       lockRankDefer:         "defer",
-       lockRankScavenge:      "scavenge",
-       lockRankForcegc:       "forcegc",
+       lockRankCpuprof:       "cpuprof",
        lockRankSched:         "sched",
        lockRankAllg:          "allg",
        lockRankAllp:          "allp",
        lockRankTimers:        "timers",
-       lockRankReflectOffs:   "reflectOffs",
+       lockRankNetpollInit:   "netpollInit",
        lockRankHchan:         "hchan",
+       lockRankNotifyList:    "notifyList",
+       lockRankSudog:         "sudog",
+       lockRankRwmutexW:      "rwmutexW",
+       lockRankRwmutexR:      "rwmutexR",
+       lockRankRoot:          "root",
+       lockRankItab:          "itab",
+       lockRankReflectOffs:   "reflectOffs",
        lockRankTraceBuf:      "traceBuf",
        lockRankTraceStrings:  "traceStrings",
+       lockRankFin:           "fin",
+       lockRankGcBitsArenas:  "gcBitsArenas",
+       lockRankMheapSpecial:  "mheapSpecial",
        lockRankMspanSpecial:  "mspanSpecial",
+       lockRankSpanSetSpine:  "spanSetSpine",
        lockRankProfInsert:    "profInsert",
        lockRankProfBlock:     "profBlock",
        lockRankProfMemActive: "profMemActive",
-       lockRankGcBitsArenas:  "gcBitsArenas",
-       lockRankSpanSetSpine:  "spanSetSpine",
-       lockRankMheapSpecial:  "mheapSpecial",
-       lockRankFin:           "fin",
        lockRankProfMemFuture: "profMemFuture",
        lockRankTrace:         "trace",
        lockRankTraceStackTab: "traceStackTab",
-       lockRankNetpollInit:   "netpollInit",
-       lockRankRwmutexR:      "rwmutexR",
        lockRankGscan:         "gscan",
        lockRankStackpool:     "stackpool",
        lockRankStackLarge:    "stackLarge",
        lockRankHchanLeaf:     "hchanLeaf",
-       lockRankSudog:         "sudog",
        lockRankWbufSpans:     "wbufSpans",
        lockRankMheap:         "mheap",
        lockRankGlobalAlloc:   "globalAlloc",
+       lockRankDeadlock:      "deadlock",
        lockRankPanic:         "panic",
 }
 
@@ -129,47 +135,47 @@ func (rank lockRank) String() string {
 // Lock ranks that allow self-cycles list themselves.
 var lockPartialOrder [][]lockRank = [][]lockRank{
        lockRankSysmon:        {},
+       lockRankScavenge:      {lockRankSysmon},
+       lockRankForcegc:       {lockRankSysmon},
+       lockRankDefer:         {},
        lockRankSweepWaiters:  {},
        lockRankAssistQueue:   {},
-       lockRankCpuprof:       {},
        lockRankSweep:         {},
        lockRankPollDesc:      {},
-       lockRankDeadlock:      {},
-       lockRankItab:          {},
+       lockRankCpuprof:       {},
+       lockRankSched:         {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof},
+       lockRankAllg:          {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched},
+       lockRankAllp:          {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched},
+       lockRankTimers:        {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllp, lockRankTimers},
+       lockRankNetpollInit:   {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllp, lockRankTimers},
+       lockRankHchan:         {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankHchan},
        lockRankNotifyList:    {},
-       lockRankRoot:          {},
+       lockRankSudog:         {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankHchan, lockRankNotifyList},
        lockRankRwmutexW:      {},
-       lockRankDefer:         {},
-       lockRankScavenge:      {lockRankSysmon},
-       lockRankForcegc:       {lockRankSysmon},
-       lockRankSched:         {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankScavenge, lockRankForcegc},
-       lockRankAllg:          {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankScavenge, lockRankForcegc, lockRankSched},
-       lockRankAllp:          {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankScavenge, lockRankForcegc, lockRankSched},
-       lockRankTimers:        {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllp, lockRankTimers},
+       lockRankRwmutexR:      {lockRankSysmon, lockRankRwmutexW},
+       lockRankRoot:          {},
+       lockRankItab:          {},
        lockRankReflectOffs:   {lockRankItab},
-       lockRankHchan:         {lockRankSysmon, lockRankSweep, lockRankScavenge, lockRankHchan},
        lockRankTraceBuf:      {lockRankSysmon, lockRankScavenge},
        lockRankTraceStrings:  {lockRankSysmon, lockRankScavenge, lockRankTraceBuf},
-       lockRankMspanSpecial:  {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankProfInsert:    {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankProfBlock:     {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankProfMemActive: {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankGcBitsArenas:  {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankSpanSetSpine:  {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankMheapSpecial:  {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankFin:           {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings},
-       lockRankProfMemFuture: {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankProfMemActive},
-       lockRankTrace:         {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankFin},
-       lockRankTraceStackTab: {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankTrace},
-       lockRankNetpollInit:   {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllp, lockRankTimers},
-       lockRankRwmutexR:      {lockRankSysmon, lockRankRwmutexW},
-       lockRankGscan:         {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit},
-       lockRankStackpool:     {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankRwmutexW, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankRwmutexR, lockRankGscan},
-       lockRankStackLarge:    {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankGscan},
-       lockRankHchanLeaf:     {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankGscan, lockRankHchanLeaf},
-       lockRankSudog:         {lockRankSysmon, lockRankSweep, lockRankNotifyList, lockRankScavenge, lockRankHchan},
-       lockRankWbufSpans:     {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankDefer, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankGscan, lockRankSudog},
-       lockRankMheap:         {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankRwmutexW, lockRankDefer, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankRwmutexR, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankSudog, lockRankWbufSpans},
-       lockRankGlobalAlloc:   {lockRankSysmon, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankItab, lockRankNotifyList, lockRankRoot, lockRankRwmutexW, lockRankDefer, lockRankScavenge, lockRankForcegc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankReflectOffs, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankMheapSpecial, lockRankFin, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankRwmutexR, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankSudog, lockRankWbufSpans, lockRankMheap},
+       lockRankFin:           {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankGcBitsArenas:  {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankMheapSpecial:  {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankMspanSpecial:  {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankSpanSetSpine:  {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankProfInsert:    {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankProfBlock:     {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankProfMemActive: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings},
+       lockRankProfMemFuture: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankProfMemActive},
+       lockRankTrace:         {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin},
+       lockRankTraceStackTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankHchan, lockRankNotifyList, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankTrace},
+       lockRankGscan:         {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab},
+       lockRankStackpool:     {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankRwmutexW, lockRankRwmutexR, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankGscan},
+       lockRankStackLarge:    {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankGscan},
+       lockRankHchanLeaf:     {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankGscan, lockRankHchanLeaf},
+       lockRankWbufSpans:     {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankSudog, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankMspanSpecial, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankGscan},
+       lockRankMheap:         {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankSudog, lockRankRwmutexW, lockRankRwmutexR, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankMspanSpecial, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans},
+       lockRankGlobalAlloc:   {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankNetpollInit, lockRankHchan, lockRankNotifyList, lockRankSudog, lockRankRwmutexW, lockRankRwmutexR, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankGcBitsArenas, lockRankMheapSpecial, lockRankMspanSpecial, lockRankSpanSetSpine, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankTrace, lockRankTraceStackTab, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap},
+       lockRankDeadlock:      {},
        lockRankPanic:         {lockRankDeadlock},
 }

diff --git a/src/runtime/mklockrank.go b/src/runtime/mklockrank.go
index d0b882415c11d742c19328a1e3677efbfa2ed455..fc7c0223e45ed43dda6434459723f9f037560548 100644 (file)
--- a/src/runtime/mklockrank.go
+++ b/src/runtime/mklockrank.go
@@ -32,42 +32,144 @@ import (
 // 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.
 //
+// Ranks in all caps are pseudo-nodes that help define order, but do
+// not actually define a rank.
+//
 // TODO: It's often hard to correlate rank names to locks. Change
 // these to be more consistent with the locks they label.
 const ranks = `
-NONE < sysmon, sweepWaiters, assistQueue, cpuprof, sweep, pollDesc, deadlock, itab, notifyList, root, rwmutexW, defer;
-sysmon < scavenge, forcegc;
-assistQueue, cpuprof, forcegc, pollDesc, scavenge, sweep, sweepWaiters < sched;
+# Sysmon
+NONE
+< sysmon
+< scavenge, forcegc;
+
+# Defer
+NONE < defer;
+
+# GC
+NONE <
+  sweepWaiters,
+  assistQueue,
+  sweep;
+
+# Scheduler, timers, netpoll
+NONE < pollDesc, cpuprof;
+assistQueue,
+  cpuprof,
+  forcegc,
+  pollDesc, # pollDesc can interact with timers, which can lock sched.
+  scavenge,
+  sweep,
+  sweepWaiters
+< sched;
 sched < allg, allp;
 allp < timers;
-itab < reflectOffs;
+timers < netpollInit;
+
+# Channels
 scavenge, sweep < hchan;
-scavenge < traceBuf;
+NONE < notifyList;
+hchan, notifyList < sudog;
+
+# RWMutex
+NONE < rwmutexW;
+rwmutexW, sysmon < rwmutexR;
+
+# Semaphores
+NONE < root;
+
+# Itabs
+NONE
+< itab
+< reflectOffs;
+
+# Tracing without a P uses a global trace buffer.
+scavenge
+# Above TRACEGLOBAL can emit a trace event without a P.
+< TRACEGLOBAL
+# Below TRACEGLOBAL manages the global tracing buffer.
+# Note that traceBuf eventually chains to MALLOC, but we never get that far
+# in the situation where there's no P.
+< traceBuf;
+# Starting/stopping tracing traces strings.
 traceBuf < traceStrings;
-allg, hchan, notifyList, reflectOffs, timers, traceStrings < mspanSpecial, profInsert, profBlock, profMemActive, gcBitsArenas, spanSetSpine, mheapSpecial, fin;
+
+# Malloc
+allg,
+  hchan,
+  notifyList,
+  reflectOffs,
+  timers,
+  traceStrings
+# Above MALLOC are things that can allocate memory.
+< MALLOC
+# Below MALLOC is the malloc implementation.
+< fin,
+  gcBitsArenas,
+  mheapSpecial,
+  mspanSpecial,
+  spanSetSpine,
+  MPROF;
+
+# Memory profiling
+MPROF < profInsert, profBlock, profMemActive;
 profMemActive < profMemFuture;
-hchan, root, sched, traceStrings, notifyList, fin < trace;
-trace < traceStackTab;
-timers < netpollInit;
-rwmutexW, sysmon < rwmutexR;
-gcBitsArenas, netpollInit, profBlock, profInsert, profMemFuture, spanSetSpine, traceStackTab < gscan;
+
+# Execution tracer events (with a P)
+hchan,
+  root,
+  sched,
+  traceStrings,
+  notifyList,
+  fin
+# Above TRACE is anything that can create a trace event
+< TRACE
+< trace
+< traceStackTab;
+
+# Stack allocation and copying
+gcBitsArenas,
+  netpollInit,
+  profBlock,
+  profInsert,
+  profMemFuture,
+  spanSetSpine,
+  traceStackTab
+# Anything that can grow the stack can acquire STACKGROW.
+# (Most higher layers imply STACKGROW, like MALLOC.)
+< STACKGROW
+# Below STACKGROW is the stack allocator/copying implementation.
+< gscan;
 gscan, rwmutexR < stackpool;
 gscan < stackLarge;
-
-# 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 use this hchanLeaf rank in syncadjustsudogs(),
-# rather than hchan. By using this special rank, we don't allow any further
-# locks to be acquired other than more hchan locks.
+# Generally, hchan must be acquired before gscan. But in one case,
+# where we suspend a G and then shrink its stack, syncadjustsudogs
+# can acquire hchan locks while holding gscan. To allow this case,
+# we use hchanLeaf instead of hchan.
 gscan < hchanLeaf;
 
-hchan, notifyList < sudog;
-defer, gscan, mspanSpecial, sudog < wbufSpans;
-stackLarge, stackpool, wbufSpans < mheap;
+# Write barrier
+defer,
+  gscan,
+  mspanSpecial,
+  sudog
+# Anything that can have write barriers can acquire WB.
+# Above WB, we can have write barriers.
+< WB
+# Below WB is the write barrier implementation.
+< wbufSpans;
+
+# Span allocator
+stackLarge,
+  stackpool,
+  wbufSpans
+# Above mheap is anything that can call the span allocator.
+< mheap;
+# Below mheap is the span allocator implementation.
 mheap, mheapSpecial < globalAlloc;
 
 # panic is handled specially. It is implicitly below all other locks.
+NONE < deadlock;
 deadlock < panic;
 `
 
@@ -158,7 +260,11 @@ const (
 
 `)
        for _, rank := range topo {
-               fmt.Fprintf(w, "\t%s\n", cname(rank))
+               if isPseudo(rank) {
+                       fmt.Fprintf(w, "\t// %s\n", rank)
+               } else {
+                       fmt.Fprintf(w, "\t%s\n", cname(rank))
+               }
        }
        fmt.Fprintf(w, `)
 
@@ -173,7 +279,9 @@ const lockRankLeafRank lockRank = 1000
 var lockNames = []string{
 `)
        for _, rank := range topo {
-               fmt.Fprintf(w, "\t%s: %q,\n", cname(rank), rank)
+               if !isPseudo(rank) {
+                       fmt.Fprintf(w, "\t%s: %q,\n", cname(rank), rank)
+               }
        }
        fmt.Fprintf(w, `}
 
@@ -201,9 +309,14 @@ func (rank lockRank) String() string {
 var lockPartialOrder [][]lockRank = [][]lockRank{
 `)
        for _, rank := range topo {
+               if isPseudo(rank) {
+                       continue
+               }
                list := []string{}
                for _, before := range g.Edges(rank) {
-                       list = append(list, cname(before))
+                       if !isPseudo(before) {
+                               list = append(list, cname(before))
+                       }
                }
                if cyclicRanks[rank] {
                        list = append(list, cname(rank))
@@ -219,6 +332,10 @@ func cname(label string) string {
        return "lockRank" + strings.ToUpper(label[:1]) + label[1:]
 }
 
+func isPseudo(label string) bool {
+       return strings.ToUpper(label) == label
+}
+
 // generateDot emits a Graphviz dot representation of g to w.
 func generateDot(w io.Writer, g *dag.Graph) {
        fmt.Fprintf(w, "digraph g {\n")