PNG  IHDRxsBIT|d pHYs+tEXtSoftwarewww.inkscape.org<,tEXtComment File Manager

File Manager

Path: /opt/golang/1.22.0/src/runtime/

Viewing File: mklockrank.go

// Copyright 2022 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.

//go:build ignore

// mklockrank records the static rank graph of the locks in the
// runtime and generates the rank checking structures in lockrank.go.
package main

import (
	"bytes"
	"flag"
	"fmt"
	"go/format"
	"internal/dag"
	"io"
	"log"
	"os"
	"strings"
)

// ranks describes the lock rank graph. See "go doc internal/dag" for
// the syntax.
//
// "a < b" means a must be acquired before b if both are held
// (or, if b is held, a cannot be acquired).
//
// "NONE < a" means no locks may be held when a is acquired.
//
// 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.
//
// 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 = `
# Sysmon
NONE
< sysmon
< scavenge, forcegc;

# Defer
NONE < defer;

# GC
NONE <
  sweepWaiters,
  assistQueue,
  sweep;

# Test only
NONE < testR, testW;

# Scheduler, timers, netpoll
NONE <
  allocmW,
  execW,
  cpuprof,
  pollDesc,
  wakeableSleep;
assistQueue,
  cpuprof,
  forcegc,
  pollDesc, # pollDesc can interact with timers, which can lock sched.
  scavenge,
  sweep,
  sweepWaiters,
  testR,
  wakeableSleep
# Above SCHED are things that can call into the scheduler.
< SCHED
# Below SCHED is the scheduler implementation.
< allocmR,
  execR
< sched;
sched < allg, allp;
allp, wakeableSleep < timers;
timers < netpollInit;

# Channels
scavenge, sweep, testR, wakeableSleep < hchan;
NONE < notifyList;
hchan, notifyList < sudog;

# Semaphores
NONE < root;

# Itabs
NONE
< itab
< reflectOffs;

# User arena state
NONE < userArenaState;

# 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;

# Malloc
allg,
  allocmR,
  execR, # May grow stack
  execW, # May allocate after BeforeFork
  hchan,
  notifyList,
  reflectOffs,
  timers,
  traceStrings,
  userArenaState
# Above MALLOC are things that can allocate memory.
< MALLOC
# Below MALLOC is the malloc implementation.
< fin,
  spanSetSpine,
  mspanSpecial,
  MPROF;

# We can acquire gcBitsArenas for pinner bits, and
# it's guarded by mspanSpecial.
MALLOC, mspanSpecial < gcBitsArenas;

# Memory profiling
MPROF < profInsert, profBlock, profMemActive;
profMemActive < profMemFuture;

# Stack allocation and copying
gcBitsArenas,
  netpollInit,
  profBlock,
  profInsert,
  profMemFuture,
  spanSetSpine,
  fin,
  root
# 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 < stackpool;
gscan < stackLarge;
# 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;

# 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.
#
# Specials: we're allowed to allocate a special while holding
# an mspanSpecial lock, and they're part of the malloc implementation.
# Pinner bits might be freed by the span allocator.
mheap, mspanSpecial < mheapSpecial;
mheap, mheapSpecial < globalAlloc;

# Execution tracer events (with a P)
hchan,
  mheap,
  root,
  sched,
  traceStrings,
  notifyList,
  fin
# Above TRACE is anything that can create a trace event
< TRACE
< trace
< traceStackTab;

# panic is handled specially. It is implicitly below all other locks.
NONE < panic;
# deadlock is not acquired while holding panic, but it also needs to be
# below all other locks.
panic < deadlock;
# raceFini is only held while exiting.
panic < raceFini;

# RWMutex internal read lock

allocmR,
  allocmW
< allocmRInternal;

execR,
  execW
< execRInternal;

testR,
  testW
< testRInternal;
`

// cyclicRanks lists lock ranks that allow multiple locks of the same
// rank to be acquired simultaneously. The runtime enforces ordering
// within these ranks using a separate mechanism.
var cyclicRanks = map[string]bool{
	// Multiple timers are locked simultaneously in destroy().
	"timers": true,
	// Multiple hchans are acquired in hchan.sortkey() order in
	// select.
	"hchan": true,
	// Multiple hchanLeafs are acquired in hchan.sortkey() order in
	// syncadjustsudogs().
	"hchanLeaf": true,
	// The point of the deadlock lock is to deadlock.
	"deadlock": true,
}

func main() {
	flagO := flag.String("o", "", "write to `file` instead of stdout")
	flagDot := flag.Bool("dot", false, "emit graphviz output instead of Go")
	flag.Parse()
	if flag.NArg() != 0 {
		fmt.Fprintf(os.Stderr, "too many arguments")
		os.Exit(2)
	}

	g, err := dag.Parse(ranks)
	if err != nil {
		log.Fatal(err)
	}

	var out []byte
	if *flagDot {
		var b bytes.Buffer
		g.TransitiveReduction()
		// Add cyclic edges for visualization.
		for k := range cyclicRanks {
			g.AddEdge(k, k)
		}
		// Reverse the graph. It's much easier to read this as
		// a "<" partial order than a ">" partial order. This
		// ways, locks are acquired from the top going down
		// and time moves forward over the edges instead of
		// backward.
		g.Transpose()
		generateDot(&b, g)
		out = b.Bytes()
	} else {
		var b bytes.Buffer
		generateGo(&b, g)
		out, err = format.Source(b.Bytes())
		if err != nil {
			log.Fatal(err)
		}
	}

	if *flagO != "" {
		err = os.WriteFile(*flagO, out, 0666)
	} else {
		_, err = os.Stdout.Write(out)
	}
	if err != nil {
		log.Fatal(err)
	}
}

func generateGo(w io.Writer, g *dag.Graph) {
	fmt.Fprintf(w, `// Code generated by mklockrank.go; DO NOT EDIT.

package runtime

type lockRank int

`)

	// Create numeric ranks.
	topo := g.Topo()
	for i, j := 0, len(topo)-1; i < j; i, j = i+1, j-1 {
		topo[i], topo[j] = topo[j], topo[i]
	}
	fmt.Fprintf(w, `
// Constants representing the ranks of all non-leaf runtime locks, in rank order.
// Locks with lower rank must be taken before locks with higher rank,
// in addition to satisfying the partial order in lockPartialOrder.
// A few ranks allow self-cycles, which are specified in lockPartialOrder.
const (
	lockRankUnknown lockRank = iota

`)
	for _, rank := range topo {
		if isPseudo(rank) {
			fmt.Fprintf(w, "\t// %s\n", rank)
		} else {
			fmt.Fprintf(w, "\t%s\n", cname(rank))
		}
	}
	fmt.Fprintf(w, `)

// lockRankLeafRank is the rank of lock that does not have a declared rank,
// and hence is a leaf lock.
const lockRankLeafRank lockRank = 1000
`)

	// Create string table.
	fmt.Fprintf(w, `
// lockNames gives the names associated with each of the above ranks.
var lockNames = []string{
`)
	for _, rank := range topo {
		if !isPseudo(rank) {
			fmt.Fprintf(w, "\t%s: %q,\n", cname(rank), rank)
		}
	}
	fmt.Fprintf(w, `}

func (rank lockRank) String() string {
	if rank == 0 {
		return "UNKNOWN"
	}
	if rank == lockRankLeafRank {
		return "LEAF"
	}
	if rank < 0 || int(rank) >= len(lockNames) {
		return "BAD RANK"
	}
	return lockNames[rank]
}
`)

	// Create partial order structure.
	fmt.Fprintf(w, `
// lockPartialOrder is the transitive closure of the lock rank graph.
// An entry for rank X lists all of the ranks that can already be held
// when rank X is acquired.
//
// Lock ranks that allow self-cycles list themselves.
var lockPartialOrder [][]lockRank = [][]lockRank{
`)
	for _, rank := range topo {
		if isPseudo(rank) {
			continue
		}
		list := []string{}
		for _, before := range g.Edges(rank) {
			if !isPseudo(before) {
				list = append(list, cname(before))
			}
		}
		if cyclicRanks[rank] {
			list = append(list, cname(rank))
		}

		fmt.Fprintf(w, "\t%s: {%s},\n", cname(rank), strings.Join(list, ", "))
	}
	fmt.Fprintf(w, "}\n")
}

// cname returns the Go const name for the given lock rank label.
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")

	// Define all nodes.
	for _, node := range g.Nodes {
		fmt.Fprintf(w, "%q;\n", node)
	}

	// Create edges.
	for _, node := range g.Nodes {
		for _, to := range g.Edges(node) {
			fmt.Fprintf(w, "%q -> %q;\n", node, to)
		}
	}

	fmt.Fprintf(w, "}\n")
}
b IDATxytVսϓ22 A@IR :hCiZ[v*E:WũZA ^dQeQ @ !jZ'>gsV仿$|?g)&x-EIENT ;@xT.i%-X}SvS5.r/UHz^_$-W"w)Ɗ/@Z &IoX P$K}JzX:;` &, ŋui,e6mX ԵrKb1ԗ)DADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADADA݀!I*]R;I2$eZ#ORZSrr6mteffu*((Pu'v{DIߔ4^pIm'77WEEE;vƎ4-$]'RI{\I&G :IHJ DWBB=\WR޽m o$K(V9ABB.}jѢv`^?IOȅ} ڶmG}T#FJ`56$-ھ}FI&v;0(h;Б38CӧOWf!;A i:F_m9s&|q%=#wZprrrla A &P\\СC[A#! {olF} `E2}MK/vV)i{4BffV\|ۭX`b@kɶ@%i$K z5zhmX[IXZ` 'b%$r5M4º/l ԃߖxhʔ)[@=} K6IM}^5k㏷݆z ΗÿO:gdGBmyT/@+Vɶ纽z񕏵l.y޴it뭷zV0[Y^>Wsqs}\/@$(T7f.InݺiR$푔n.~?H))\ZRW'Mo~v Ov6oԃxz! S,&xm/yɞԟ?'uaSѽb,8GלKboi&3t7Y,)JJ c[nzӳdE&KsZLӄ I?@&%ӟ۶mSMMњ0iؐSZ,|J+N ~,0A0!5%Q-YQQa3}$_vVrf9f?S8`zDADADADADADADADADAdqP,تmMmg1V?rSI꒟]u|l RCyEf٢9 jURbztѰ!m5~tGj2DhG*{H9)꒟ר3:(+3\?/;TUݭʴ~S6lڧUJ*i$d(#=Yݺd{,p|3B))q:vN0Y.jkק6;SɶVzHJJЀ-utѹսk>QUU\޲~]fFnK?&ߡ5b=z9)^|u_k-[y%ZNU6 7Mi:]ۦtk[n X(e6Bb."8cۭ|~teuuw|ήI-5"~Uk;ZicEmN/:]M> cQ^uiƞ??Ңpc#TUU3UakNwA`:Y_V-8.KKfRitv޲* 9S6ֿj,ՃNOMߤ]z^fOh|<>@Å5 _/Iu?{SY4hK/2]4%it5q]GGe2%iR| W&f*^]??vq[LgE_3f}Fxu~}qd-ږFxu~I N>\;͗O֊:̗WJ@BhW=y|GgwܷH_NY?)Tdi'?խwhlmQi !SUUsw4kӺe4rfxu-[nHtMFj}H_u~w>)oV}(T'ebʒv3_[+vn@Ȭ\S}ot}w=kHFnxg S 0eޢm~l}uqZfFoZuuEg `zt~? b;t%>WTkķh[2eG8LIWx,^\thrl^Ϊ{=dž<}qV@ ⠨Wy^LF_>0UkDuʫuCs$)Iv:IK;6ֲ4{^6եm+l3>݆uM 9u?>Zc }g~qhKwڭeFMM~pМuqǿz6Tb@8@Y|jx](^]gf}M"tG -w.@vOqh~/HII`S[l.6nØXL9vUcOoB\xoǤ'T&IǍQw_wpv[kmO{w~>#=P1Pɞa-we:iǏlHo׈꒟f9SzH?+shk%Fs:qVhqY`jvO'ρ?PyX3lх]˾uV{ݞ]1,MzYNW~̈́ joYn}ȚF߾׮mS]F z+EDxm/d{F{-W-4wY듏:??_gPf ^3ecg ҵs8R2מz@TANGj)}CNi/R~}c:5{!ZHӋӾ6}T]G]7W6^n 9*,YqOZj:P?Q DFL|?-^.Ɵ7}fFh׶xe2Pscz1&5\cn[=Vn[ĶE鎀uˌd3GII k;lNmشOuuRVfBE]ۣeӶu :X-[(er4~LHi6:Ѻ@ԅrST0trk%$Č0ez" *z"T/X9|8.C5Feg}CQ%͞ˣJvL/?j^h&9xF`њZ(&yF&Iݻfg#W;3^{Wo^4'vV[[K';+mӍִ]AC@W?1^{එyh +^]fm~iԵ]AB@WTk̏t uR?l.OIHiYyԶ]Aˀ7c:q}ힽaf6Z~қm(+sK4{^6}T*UUu]n.:kx{:2 _m=sAߤU@?Z-Vކеz왍Nэ{|5 pڶn b p-@sPg]0G7fy-M{GCF'%{4`=$-Ge\ eU:m+Zt'WjO!OAF@ik&t݆ϥ_ e}=]"Wz_.͜E3leWFih|t-wZۍ-uw=6YN{6|} |*={Ѽn.S.z1zjۻTH]흾 DuDvmvK.`V]yY~sI@t?/ϓ. m&["+P?MzovVЫG3-GRR[(!!\_,^%?v@ҵő m`Y)tem8GMx.))A]Y i`ViW`?^~!S#^+ѽGZj?Vģ0.))A꨷lzL*]OXrY`DBBLOj{-MH'ii-ϰ ok7^ )쭡b]UXSְmռY|5*cֽk0B7镹%ڽP#8nȎq}mJr23_>lE5$iwui+ H~F`IjƵ@q \ @#qG0".0" l`„.0! ,AQHN6qzkKJ#o;`Xv2>,tێJJ7Z/*A .@fفjMzkg @TvZH3Zxu6Ra'%O?/dQ5xYkU]Rֽkق@DaS^RSּ5|BeHNN͘p HvcYcC5:y #`οb;z2.!kr}gUWkyZn=f Pvsn3p~;4p˚=ē~NmI] ¾ 0lH[_L hsh_ғߤc_њec)g7VIZ5yrgk̞W#IjӪv>՞y睝M8[|]\շ8M6%|@PZڨI-m>=k='aiRo-x?>Q.}`Ȏ:Wsmu u > .@,&;+!!˱tﭧDQwRW\vF\~Q7>spYw$%A~;~}6¾ g&if_=j,v+UL1(tWake:@Ș>j$Gq2t7S?vL|]u/ .(0E6Mk6hiۺzښOrifޱxm/Gx> Lal%%~{lBsR4*}{0Z/tNIɚpV^#Lf:u@k#RSu =S^ZyuR/.@n&΃z~B=0eg뺆#,Þ[B/?H uUf7y Wy}Bwegל`Wh(||`l`.;Ws?V@"c:iɍL֯PGv6zctM̠':wuW;d=;EveD}9J@B(0iհ bvP1{\P&G7D޴Iy_$-Qjm~Yrr&]CDv%bh|Yzni_ˆR;kg}nJOIIwyuL}{ЌNj}:+3Y?:WJ/N+Rzd=hb;dj͒suݔ@NKMԄ jqzC5@y°hL m;*5ezᕏ=ep XL n?מ:r`۵tŤZ|1v`V뽧_csج'ߤ%oTuumk%%%h)uy]Nk[n 'b2 l.=͜E%gf$[c;s:V-͞WߤWh-j7]4=F-X]>ZLSi[Y*We;Zan(ӇW|e(HNNP5[= r4tP &0<pc#`vTNV GFqvTi*Tyam$ߏWyE*VJKMTfFw>'$-ؽ.Ho.8c"@DADADADADADADADADA~j*֘,N;Pi3599h=goضLgiJ5փy~}&Zd9p֚ e:|hL``b/d9p? fgg+%%hMgXosج, ΩOl0Zh=xdjLmhݻoO[g_l,8a]٭+ӧ0$I]c]:粹:Teꢢ"5a^Kgh,&= =՟^߶“ߢE ܹS J}I%:8 IDAT~,9/ʃPW'Mo}zNƍ쨓zPbNZ~^z=4mswg;5 Y~SVMRXUյڱRf?s:w ;6H:ºi5-maM&O3;1IKeamZh͛7+##v+c ~u~ca]GnF'ټL~PPPbn voC4R,ӟgg %hq}@#M4IÇ Oy^xMZx ) yOw@HkN˖-Sǎmb]X@n+i͖!++K3gd\$mt$^YfJ\8PRF)77Wא!Cl$i:@@_oG I{$# 8磌ŋ91A (Im7֭>}ߴJq7ޗt^ -[ԩSj*}%]&' -ɓ'ꫯVzzvB#;a 7@GxI{j޼ƌ.LÇWBB7`O"I$/@R @eee@۷>}0,ɒ2$53Xs|cS~rpTYYY} kHc %&k.], @ADADADADADADADADA@lT<%''*Lo^={رc5h %$+CnܸQ3fҥK}vUVVs9G R,_{xˇ3o߾;TTTd}馛]uuuG~iԩ@4bnvmvfϞ /Peeeq}}za I~,誫{UWW뮻}_~YƍSMMMYχ֝waw\ďcxꩧtEƍկ_?۷5@u?1kNׯWzz/wy>}zj3 k(ٺuq_Zvf̘:~ ABQ&r|!%KҥKgԞ={<_X-z !CyFUUz~ ABQIIIjݺW$UXXDٳZ~ ABQƍecW$<(~<RSSvZujjjԧOZQu@4 8m&&&jԩg$ď1h ͟?_{768@g =@`)))5o6m3)ѣƌJ;wҿUTT /KZR{~a=@0o<*狔iFɶ[ˎ;T]]OX@?K.ۈxN pppppppppppppppppPfl߾] ,{ァk۶mڿo5BTӦMӴiӴ|r DB2e|An!Dy'tkΝ[A $***t5' "!駟oaDnΝ:t֭[gDШQ06qD;@ x M6v(PiizmZ4ew"@̴ixf [~-Fٱc&IZ2|n!?$@{[HTɏ#@hȎI# _m(F /6Z3z'\r,r!;w2Z3j=~GY7"I$iI.p_"?pN`y DD?: _  Gÿab7J !Bx@0 Bo cG@`1C[@0G @`0C_u V1 aCX>W ` | `!<S `"<. `#c`?cAC4 ?c p#~@0?:08&_MQ1J h#?/`7;I  q 7a wQ A 1 Hp !#<8/#@1Ul7=S=K.4Z?E_$i@!1!E4?`P_  @Bă10#: "aU,xbFY1 [n|n #'vEH:`xb #vD4Y hi.i&EΖv#O H4IŶ}:Ikh @tZRF#(tXҙzZ ?I3l7q@õ|ۍ1,GpuY Ꮿ@hJv#xxk$ v#9 5 }_$c S#=+"K{F*m7`#%H:NRSp6I?sIՖ{Ap$I$I:QRv2$Z @UJ*$]<FO4IENDB`