runtime: replace func-based write barrier skipping with type-based
This CL revises CL 7504 to use explicitly uintptr types for the
struct fields that are going to be updated sometimes without
write barriers. The result is that the fields are now updated *always*
without write barriers.
This approach has two important properties:
1) Now the GC never looks at the field, so if the missing reference
could cause a problem, it will do so all the time, not just when the
write barrier is missed at just the right moment.
2) Now a write barrier never happens for the field, avoiding the
(correct) detection of inconsistent write barriers when GODEBUG=wbshadow=1.
Change-Id: Iebd3962c727c0046495cc08914a8dc0808460e0e
Reviewed-on: https://go-review.googlesource.com/9019
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index e41c273..5fe0b16 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -817,8 +817,8 @@
mp := acquirem()
var persistent *persistentAlloc
- if mp != nil && mp.p != nil {
- persistent = &mp.p.palloc
+ if mp != nil && mp.p != 0 {
+ persistent = &mp.p.ptr().palloc
} else {
lock(&globalAlloc.mutex)
persistent = &globalAlloc.persistentAlloc
diff --git a/src/runtime/mbarrier.go b/src/runtime/mbarrier.go
index 2e3e4d8..9bf0e6b 100644
--- a/src/runtime/mbarrier.go
+++ b/src/runtime/mbarrier.go
@@ -92,10 +92,6 @@
// the p associated with an m. We use the fact that m.p == nil to indicate
// that we are in one these critical section and throw if the write is of
// a pointer to a heap object.
-// The p, m, and g pointers are the pointers that are used by the scheduler
-// and need to be operated on without write barriers. We use
-// the setPNoWriteBarrier, setMNoWriteBarrier and setGNowriteBarrier to
-// avoid having to do the write barrier.
//go:nosplit
func writebarrierptr_nostore1(dst *uintptr, src uintptr) {
mp := acquirem()
@@ -104,7 +100,7 @@
return
}
systemstack(func() {
- if mp.p == nil && memstats.enablegc && !mp.inwb && inheap(src) {
+ if mp.p == 0 && memstats.enablegc && !mp.inwb && inheap(src) {
throw("writebarrierptr_nostore1 called with mp.p == nil")
}
mp.inwb = true
diff --git a/src/runtime/netpoll.go b/src/runtime/netpoll.go
index 4791e5e..c06722f 100644
--- a/src/runtime/netpoll.go
+++ b/src/runtime/netpoll.go
@@ -275,24 +275,22 @@
// make pd ready, newly runnable goroutines (if any) are returned in rg/wg
// May run during STW, so write barriers are not allowed.
-// Eliminating WB calls using setGNoWriteBarrier are safe since the gs are
-// reachable through allg.
//go:nowritebarrier
-func netpollready(gpp **g, pd *pollDesc, mode int32) {
- var rg, wg *g
+func netpollready(gpp *guintptr, pd *pollDesc, mode int32) {
+ var rg, wg guintptr
if mode == 'r' || mode == 'r'+'w' {
- setGNoWriteBarrier(&rg, netpollunblock(pd, 'r', true))
+ rg.set(netpollunblock(pd, 'r', true))
}
if mode == 'w' || mode == 'r'+'w' {
- setGNoWriteBarrier(&wg, netpollunblock(pd, 'w', true))
+ wg.set(netpollunblock(pd, 'w', true))
}
- if rg != nil {
- setGNoWriteBarrier(&rg.schedlink, *gpp)
- setGNoWriteBarrier(gpp, rg)
+ if rg != 0 {
+ rg.ptr().schedlink = *gpp
+ *gpp = rg
}
- if wg != nil {
- setGNoWriteBarrier(&wg.schedlink, *gpp)
- setGNoWriteBarrier(gpp, wg)
+ if wg != 0 {
+ wg.ptr().schedlink = *gpp
+ *gpp = wg
}
}
diff --git a/src/runtime/netpoll_epoll.go b/src/runtime/netpoll_epoll.go
index 4f9ccaf..7b4052a 100644
--- a/src/runtime/netpoll_epoll.go
+++ b/src/runtime/netpoll_epoll.go
@@ -55,9 +55,9 @@
// polls for ready network connections
// returns list of goroutines that become runnable
-func netpoll(block bool) (gp *g) {
+func netpoll(block bool) *g {
if epfd == -1 {
- return
+ return nil
}
waitms := int32(-1)
if !block {
@@ -73,6 +73,7 @@
}
goto retry
}
+ var gp guintptr
for i := int32(0); i < n; i++ {
ev := &events[i]
if ev.events == 0 {
@@ -87,11 +88,12 @@
}
if mode != 0 {
pd := *(**pollDesc)(unsafe.Pointer(&ev.data))
- netpollready((**g)(noescape(unsafe.Pointer(&gp))), pd, mode)
+
+ netpollready(&gp, pd, mode)
}
}
- if block && gp == nil {
+ if block && gp == 0 {
goto retry
}
- return gp
+ return gp.ptr()
}
diff --git a/src/runtime/netpoll_kqueue.go b/src/runtime/netpoll_kqueue.go
index 080964b..01445dc 100644
--- a/src/runtime/netpoll_kqueue.go
+++ b/src/runtime/netpoll_kqueue.go
@@ -62,9 +62,9 @@
// Polls for ready network connections.
// Returns list of goroutines that become runnable.
-func netpoll(block bool) (gp *g) {
+func netpoll(block bool) *g {
if kq == -1 {
- return
+ return nil
}
var tp *timespec
var ts timespec
@@ -81,6 +81,7 @@
}
goto retry
}
+ var gp guintptr
for i := 0; i < int(n); i++ {
ev := &events[i]
var mode int32
@@ -91,11 +92,11 @@
mode += 'w'
}
if mode != 0 {
- netpollready((**g)(noescape(unsafe.Pointer(&gp))), (*pollDesc)(unsafe.Pointer(ev.udata)), mode)
+ netpollready(&gp, (*pollDesc)(unsafe.Pointer(ev.udata)), mode)
}
}
- if block && gp == nil {
+ if block && gp == 0 {
goto retry
}
- return gp
+ return gp.ptr()
}
diff --git a/src/runtime/netpoll_solaris.go b/src/runtime/netpoll_solaris.go
index d8f050e..abfe56d 100644
--- a/src/runtime/netpoll_solaris.go
+++ b/src/runtime/netpoll_solaris.go
@@ -179,9 +179,9 @@
// polls for ready network connections
// returns list of goroutines that become runnable
-func netpoll(block bool) (gp *g) {
+func netpoll(block bool) *g {
if portfd == -1 {
- return
+ return nil
}
var wait *timespec
@@ -201,7 +201,7 @@
goto retry
}
- gp = nil
+ var gp guintptr
for i := 0; i < int(n); i++ {
ev := &events[i]
@@ -232,12 +232,12 @@
}
if mode != 0 {
- netpollready((**g)(noescape(unsafe.Pointer(&gp))), pd, mode)
+ netpollready(&gp, pd, mode)
}
}
- if block && gp == nil {
+ if block && gp == 0 {
goto retry
}
- return gp
+ return gp.ptr()
}
diff --git a/src/runtime/netpoll_windows.go b/src/runtime/netpoll_windows.go
index 0861e20..7e15cd2 100644
--- a/src/runtime/netpoll_windows.go
+++ b/src/runtime/netpoll_windows.go
@@ -63,14 +63,13 @@
var wait, qty, key, flags, n, i uint32
var errno int32
var op *net_op
- var gp *g
+ var gp guintptr
mp := getg().m
if iocphandle == _INVALID_HANDLE_VALUE {
return nil
}
- gp = nil
wait = 0
if block {
wait = _INFINITE
@@ -125,13 +124,13 @@
mp.blocked = false
handlecompletion(&gp, op, errno, qty)
}
- if block && gp == nil {
+ if block && gp == 0 {
goto retry
}
- return gp
+ return gp.ptr()
}
-func handlecompletion(gpp **g, op *net_op, errno int32, qty uint32) {
+func handlecompletion(gpp *guintptr, op *net_op, errno int32, qty uint32) {
if op == nil {
throw("netpoll: GetQueuedCompletionStatus returned op == nil")
}
@@ -142,5 +141,5 @@
}
op.errno = errno
op.qty = qty
- netpollready((**g)(noescape(unsafe.Pointer(gpp))), op.pd, mode)
+ netpollready(gpp, op.pd, mode)
}
diff --git a/src/runtime/os1_windows.go b/src/runtime/os1_windows.go
index 8df2968..2b9739f 100644
--- a/src/runtime/os1_windows.go
+++ b/src/runtime/os1_windows.go
@@ -363,8 +363,7 @@
if mp.profilehz != 0 {
// leave pc/sp for cpu profiler
- // gp is on allg, so this WB can be eliminated.
- setGNoWriteBarrier(&mp.libcallg, gp)
+ mp.libcallg.set(gp)
mp.libcallpc = getcallerpc(unsafe.Pointer(&fn))
// sp must be the last, because once async cpu profiler finds
// all three values to be non-zero, it will use them
diff --git a/src/runtime/os3_plan9.go b/src/runtime/os3_plan9.go
index fa49ad6..248576a 100644
--- a/src/runtime/os3_plan9.go
+++ b/src/runtime/os3_plan9.go
@@ -81,7 +81,7 @@
}
Throw:
_g_.m.throwing = 1
- setGNoWriteBarrier(&_g_.m.caughtsig, gp)
+ _g_.m.caughtsig.set(gp)
startpanic()
print(notestr, "\n")
print("PC=", hex(c.pc()), "\n")
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 9b937f5..0e4086c 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -165,7 +165,7 @@
sc := deferclass(uintptr(siz))
mp := acquirem()
if sc < uintptr(len(p{}.deferpool)) {
- pp := mp.p
+ pp := mp.p.ptr()
if len(pp.deferpool[sc]) == 0 && sched.deferpool[sc] != nil {
lock(&sched.deferlock)
for len(pp.deferpool[sc]) < cap(pp.deferpool[sc])/2 && sched.deferpool[sc] != nil {
@@ -223,7 +223,7 @@
sc := deferclass(uintptr(d.siz))
if sc < uintptr(len(p{}.deferpool)) {
mp := acquirem()
- pp := mp.p
+ pp := mp.p.ptr()
if len(pp.deferpool[sc]) == cap(pp.deferpool[sc]) {
// Transfer half of local cache to the central cache.
var first, last *_defer
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 88b2004..f725fc8 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -208,7 +208,7 @@
// The acquirem/releasem increments m.locks during new(sudog),
// which keeps the garbage collector from being invoked.
mp := acquirem()
- pp := mp.p
+ pp := mp.p.ptr()
if len(pp.sudogcache) == 0 {
lock(&sched.sudoglock)
// First, try to grab a batch from central cache.
@@ -257,7 +257,7 @@
throw("runtime: releaseSudog with non-nil gp.param")
}
mp := acquirem() // avoid rescheduling to another P
- pp := mp.p
+ pp := mp.p.ptr()
if len(pp.sudogcache) == cap(pp.sudogcache) {
// Transfer half of local cache to the central cache.
var first, last *sudog
diff --git a/src/runtime/proc1.go b/src/runtime/proc1.go
index a46ebc8..cf6e604 100644
--- a/src/runtime/proc1.go
+++ b/src/runtime/proc1.go
@@ -145,7 +145,7 @@
// status is Gwaiting or Gscanwaiting, make Grunnable and put on runq
casgstatus(gp, _Gwaiting, _Grunnable)
- runqput(_g_.m.p, gp)
+ runqput(_g_.m.p.ptr(), gp)
if atomicload(&sched.npidle) != 0 && atomicload(&sched.nmspinning) == 0 { // TODO: fast atomic
wakep()
}
@@ -185,7 +185,7 @@
// Preempt the current g
casgstatus(_g_, _Grunning, _Grunnable)
- runqput(_g_.m.p, _g_)
+ runqput(_g_.m.p.ptr(), _g_)
dropg()
// Ready gp and switch to it
@@ -239,7 +239,7 @@
throw("gcprocs inconsistency")
}
mp.helpgc = n
- mp.p = allp[pos]
+ mp.p.set(allp[pos])
mp.mcache = allp[pos].mcache
pos++
notewakeup(&mp.park)
@@ -603,7 +603,7 @@
atomicstore(&sched.gcwaiting, 1)
preemptall()
// stop current P
- _g_.m.p.status = _Pgcstop // Pgcstop is only diagnostic.
+ _g_.m.p.ptr().status = _Pgcstop // Pgcstop is only diagnostic.
sched.stopwait--
// try to retake all P's in Psyscall status
for i := 0; i < int(gomaxprocs); i++ {
@@ -681,14 +681,14 @@
for p1 != nil {
p := p1
- p1 = p1.link
- if p.m != nil {
- mp := p.m
- p.m = nil
- if mp.nextp != nil {
+ p1 = p1.link.ptr()
+ if p.m != 0 {
+ mp := p.m.ptr()
+ p.m = 0
+ if mp.nextp != 0 {
throw("starttheworld: inconsistent mp->nextp")
}
- mp.nextp = p
+ mp.nextp.set(p)
notewakeup(&mp.park)
} else {
// Start M to run P. Do not start another M below.
@@ -768,8 +768,7 @@
initsig()
}
- if _g_.m.mstartfn != 0 {
- fn := *(*func())(unsafe.Pointer(&_g_.m.mstartfn))
+ if fn := _g_.m.mstartfn; fn != nil {
fn()
}
@@ -777,8 +776,8 @@
_g_.m.helpgc = 0
stopm()
} else if _g_.m != &m0 {
- acquirep(_g_.m.nextp)
- _g_.m.nextp = nil
+ acquirep(_g_.m.nextp.ptr())
+ _g_.m.nextp = 0
}
schedule()
}
@@ -789,20 +788,22 @@
var cgoThreadStart unsafe.Pointer
type cgothreadstart struct {
- g *g
+ g guintptr
tls *uint64
fn unsafe.Pointer
}
// Allocate a new m unassociated with any thread.
// Can use p for allocation context if needed.
-func allocm(_p_ *p) *m {
+// fn is recorded as the new m's m.mstartfn.
+func allocm(_p_ *p, fn func()) *m {
_g_ := getg()
_g_.m.locks++ // disable GC because it can be called from sysmon
- if _g_.m.p == nil {
+ if _g_.m.p == 0 {
acquirep(_p_) // temporarily borrow p for mallocs in this function
}
mp := new(m)
+ mp.mstartfn = fn
mcommoninit(mp)
// In case of cgo or Solaris, pthread_create will make us a stack.
@@ -814,7 +815,7 @@
}
mp.g0.m = mp
- if _p_ == _g_.m.p {
+ if _p_ == _g_.m.p.ptr() {
releasep()
}
_g_.m.locks--
@@ -880,8 +881,8 @@
// after exitsyscall makes sure it is okay to be
// running at all (that is, there's no garbage collection
// running right now).
- mp.needextram = mp.schedlink == nil
- unlockextra(mp.schedlink)
+ mp.needextram = mp.schedlink == 0
+ unlockextra(mp.schedlink.ptr())
// Install g (= m->g0) and set the stack bounds
// to match the current stack. We don't actually know
@@ -910,7 +911,7 @@
// The sched.pc will never be returned to, but setting it to
// goexit makes clear to the traceback routines where
// the goroutine stack ends.
- mp := allocm(nil)
+ mp := allocm(nil, nil)
gp := malg(4096)
gp.sched.pc = funcPC(goexit) + _PCQuantum
gp.sched.sp = gp.stack.hi
@@ -936,7 +937,7 @@
// Add m to the extra list.
mnext := lockextra(true)
- mp.schedlink = mnext
+ mp.schedlink.set(mnext)
unlockextra(mp)
}
@@ -972,7 +973,7 @@
// with no pointer manipulation.
mp := getg().m
mnext := lockextra(true)
- mp.schedlink = mnext
+ mp.schedlink.set(mnext)
setg(nil)
unlockextra(mp)
@@ -1019,18 +1020,14 @@
// May run with m.p==nil, so write barriers are not allowed.
//go:nowritebarrier
func newm(fn func(), _p_ *p) {
- mp := allocm(_p_)
- // procresize made _p_ reachable through allp, which doesn't change during GC, so WB can be eliminated
- setPNoWriteBarrier(&mp.nextp, _p_)
- // Store &fn as a uintptr since it is not heap allocated so the WB can be eliminated
- mp.mstartfn = *(*uintptr)(unsafe.Pointer(&fn))
+ mp := allocm(_p_, fn)
+ mp.nextp.set(_p_)
if iscgo {
var ts cgothreadstart
if _cgo_thread_start == nil {
throw("_cgo_thread_start missing")
}
- // mp is reachable via allm and mp.g0 never changes, so WB can be eliminated.
- setGNoWriteBarrier(&ts.g, mp.g0)
+ ts.g.set(mp.g0)
ts.tls = (*uint64)(unsafe.Pointer(&mp.tls[0]))
ts.fn = unsafe.Pointer(funcPC(mstart))
asmcgocall(_cgo_thread_start, unsafe.Pointer(&ts))
@@ -1047,7 +1044,7 @@
if _g_.m.locks != 0 {
throw("stopm holding locks")
}
- if _g_.m.p != nil {
+ if _g_.m.p != 0 {
throw("stopm holding p")
}
if _g_.m.spinning {
@@ -1065,11 +1062,11 @@
gchelper()
_g_.m.helpgc = 0
_g_.m.mcache = nil
- _g_.m.p = nil
+ _g_.m.p = 0
goto retry
}
- acquirep(_g_.m.nextp)
- _g_.m.nextp = nil
+ acquirep(_g_.m.nextp.ptr())
+ _g_.m.nextp = 0
}
func mspinning() {
@@ -1105,12 +1102,11 @@
if mp.spinning {
throw("startm: m is spinning")
}
- if mp.nextp != nil {
+ if mp.nextp != 0 {
throw("startm: m has p")
}
mp.spinning = spinning
- // procresize made _p_ reachable through allp, which doesn't change during GC, so WB can be eliminated
- setPNoWriteBarrier(&mp.nextp, _p_)
+ mp.nextp.set(_p_)
notewakeup(&mp.park)
}
@@ -1173,7 +1169,7 @@
if _g_.m.lockedg == nil || _g_.m.lockedg.lockedm != _g_.m {
throw("stoplockedm: inconsistent locking")
}
- if _g_.m.p != nil {
+ if _g_.m.p != 0 {
// Schedule another M to run this p.
_p_ := releasep()
handoffp(_p_)
@@ -1188,8 +1184,8 @@
dumpgstatus(_g_)
throw("stoplockedm: not runnable")
}
- acquirep(_g_.m.nextp)
- _g_.m.nextp = nil
+ acquirep(_g_.m.nextp.ptr())
+ _g_.m.nextp = 0
}
// Schedules the locked m to run the locked gp.
@@ -1202,14 +1198,13 @@
if mp == _g_.m {
throw("startlockedm: locked to me")
}
- if mp.nextp != nil {
+ if mp.nextp != 0 {
throw("startlockedm: m has p")
}
// directly handoff current P to the locked m
incidlelocked(-1)
_p_ := releasep()
- // procresize made _p_ reachable through allp, which doesn't change during GC, so WB can be eliminated
- setPNoWriteBarrier(&mp.nextp, _p_)
+ mp.nextp.set(_p_)
notewakeup(&mp.park)
stopm()
}
@@ -1246,7 +1241,7 @@
gp.waitsince = 0
gp.preempt = false
gp.stackguard0 = gp.stack.lo + _StackGuard
- _g_.m.p.schedtick++
+ _g_.m.p.ptr().schedtick++
_g_.m.curg = gp
gp.m = _g_.m
@@ -1280,14 +1275,14 @@
}
// local runq
- if gp := runqget(_g_.m.p); gp != nil {
+ if gp := runqget(_g_.m.p.ptr()); gp != nil {
return gp
}
// global runq
if sched.runqsize != 0 {
lock(&sched.lock)
- gp := globrunqget(_g_.m.p, 0)
+ gp := globrunqget(_g_.m.p.ptr(), 0)
unlock(&sched.lock)
if gp != nil {
return gp
@@ -1303,7 +1298,7 @@
if netpollinited() && sched.lastpoll != 0 {
if gp := netpoll(false); gp != nil { // non-blocking
// netpoll returns list of goroutines linked by schedlink.
- injectglist(gp.schedlink)
+ injectglist(gp.schedlink.ptr())
casgstatus(gp, _Gwaiting, _Grunnable)
if trace.enabled {
traceGoUnpark(gp, 0)
@@ -1329,10 +1324,10 @@
}
_p_ := allp[fastrand1()%uint32(gomaxprocs)]
var gp *g
- if _p_ == _g_.m.p {
+ if _p_ == _g_.m.p.ptr() {
gp = runqget(_p_)
} else {
- gp = runqsteal(_g_.m.p, _p_)
+ gp = runqsteal(_g_.m.p.ptr(), _p_)
}
if gp != nil {
return gp
@@ -1347,7 +1342,7 @@
goto top
}
if sched.runqsize != 0 {
- gp := globrunqget(_g_.m.p, 0)
+ gp := globrunqget(_g_.m.p.ptr(), 0)
unlock(&sched.lock)
return gp
}
@@ -1376,7 +1371,7 @@
// poll network
if netpollinited() && xchg64(&sched.lastpoll, 0) != 0 {
- if _g_.m.p != nil {
+ if _g_.m.p != 0 {
throw("findrunnable: netpoll with p")
}
if _g_.m.spinning {
@@ -1390,7 +1385,7 @@
unlock(&sched.lock)
if _p_ != nil {
acquirep(_p_)
- injectglist(gp.schedlink)
+ injectglist(gp.schedlink.ptr())
casgstatus(gp, _Gwaiting, _Grunnable)
if trace.enabled {
traceGoUnpark(gp, 0)
@@ -1432,7 +1427,7 @@
return
}
if trace.enabled {
- for gp := glist; gp != nil; gp = gp.schedlink {
+ for gp := glist; gp != nil; gp = gp.schedlink.ptr() {
traceGoUnpark(gp, 0)
}
}
@@ -1440,7 +1435,7 @@
var n int
for n = 0; glist != nil; n++ {
gp := glist
- glist = gp.schedlink
+ glist = gp.schedlink.ptr()
casgstatus(gp, _Gwaiting, _Grunnable)
globrunqput(gp)
}
@@ -1483,9 +1478,9 @@
// Check the global runnable queue once in a while to ensure fairness.
// Otherwise two goroutines can completely occupy the local runqueue
// by constantly respawning each other.
- if _g_.m.p.schedtick%61 == 0 && sched.runqsize > 0 {
+ if _g_.m.p.ptr().schedtick%61 == 0 && sched.runqsize > 0 {
lock(&sched.lock)
- gp = globrunqget(_g_.m.p, 1)
+ gp = globrunqget(_g_.m.p.ptr(), 1)
unlock(&sched.lock)
if gp != nil {
resetspinning()
@@ -1493,7 +1488,7 @@
}
}
if gp == nil {
- gp = runqget(_g_.m.p)
+ gp = runqget(_g_.m.p.ptr())
if gp != nil && _g_.m.spinning {
throw("schedule: spinning with local work")
}
@@ -1624,7 +1619,7 @@
throw("internal lockOSThread error")
}
_g_.m.locked = 0
- gfput(_g_.m.p, gp)
+ gfput(_g_.m.p.ptr(), gp)
schedule()
}
@@ -1671,7 +1666,7 @@
// when syscall returns we emit traceGoSysExit and when the goroutine starts running
// (potentially instantly, if exitsyscallfast returns true) we emit traceGoStart.
// To ensure that traceGoSysExit is emitted strictly after traceGoSysBlock,
-// we remember current value of syscalltick in m (_g_.m.syscalltick = _g_.m.p.syscalltick),
+// we remember current value of syscalltick in m (_g_.m.syscalltick = _g_.m.p.ptr().syscalltick),
// whoever emits traceGoSysBlock increments p.syscalltick afterwards;
// and we wait for the increment before emitting traceGoSysExit.
// Note that the increment is done even if tracing is not enabled,
@@ -1713,10 +1708,10 @@
save(pc, sp)
}
- _g_.m.syscalltick = _g_.m.p.syscalltick
+ _g_.m.syscalltick = _g_.m.p.ptr().syscalltick
_g_.m.mcache = nil
- _g_.m.p.m = nil
- atomicstore(&_g_.m.p.status, _Psyscall)
+ _g_.m.p.ptr().m = 0
+ atomicstore(&_g_.m.p.ptr().status, _Psyscall)
if sched.gcwaiting != 0 {
systemstack(entersyscall_gcwait)
save(pc, sp)
@@ -1746,7 +1741,7 @@
func entersyscall_gcwait() {
_g_ := getg()
- _p_ := _g_.m.p
+ _p_ := _g_.m.p.ptr()
lock(&sched.lock)
if sched.stopwait > 0 && cas(&_p_.status, _Psyscall, _Pgcstop) {
@@ -1770,8 +1765,8 @@
_g_.m.locks++ // see comment in entersyscall
_g_.throwsplit = true
_g_.stackguard0 = stackPreempt // see comment in entersyscall
- _g_.m.syscalltick = _g_.m.p.syscalltick
- _g_.m.p.syscalltick++
+ _g_.m.syscalltick = _g_.m.p.ptr().syscalltick
+ _g_.m.p.ptr().syscalltick++
// Leave SP around for GC and traceback.
pc := getcallerpc(unsafe.Pointer(&dummy))
@@ -1807,7 +1802,7 @@
func entersyscallblock_handoff() {
if trace.enabled {
traceGoSysCall()
- traceGoSysBlock(getg().m.p)
+ traceGoSysBlock(getg().m.p.ptr())
}
handoffp(releasep())
}
@@ -1826,18 +1821,18 @@
}
_g_.waitsince = 0
- oldp := _g_.m.p
+ oldp := _g_.m.p.ptr()
if exitsyscallfast() {
if _g_.m.mcache == nil {
throw("lost mcache")
}
if trace.enabled {
- if oldp != _g_.m.p || _g_.m.syscalltick != _g_.m.p.syscalltick {
+ if oldp != _g_.m.p.ptr() || _g_.m.syscalltick != _g_.m.p.ptr().syscalltick {
systemstack(traceGoStart)
}
}
// There's a cpu for us, so we can run.
- _g_.m.p.syscalltick++
+ _g_.m.p.ptr().syscalltick++
// We need to cas the status and scan before resuming...
casgstatus(_g_, _Gsyscall, _Grunning)
@@ -1891,7 +1886,7 @@
// we don't know for sure that the garbage collector
// is not running.
_g_.syscallsp = 0
- _g_.m.p.syscalltick++
+ _g_.m.p.ptr().syscalltick++
_g_.throwsplit = false
if exitTicks != 0 {
@@ -1909,37 +1904,37 @@
// Freezetheworld sets stopwait but does not retake P's.
if sched.stopwait == freezeStopWait {
_g_.m.mcache = nil
- _g_.m.p = nil
+ _g_.m.p = 0
return false
}
// Try to re-acquire the last P.
- if _g_.m.p != nil && _g_.m.p.status == _Psyscall && cas(&_g_.m.p.status, _Psyscall, _Prunning) {
+ if _g_.m.p != 0 && _g_.m.p.ptr().status == _Psyscall && cas(&_g_.m.p.ptr().status, _Psyscall, _Prunning) {
// There's a cpu for us, so we can run.
- _g_.m.mcache = _g_.m.p.mcache
- _g_.m.p.m = _g_.m
- if _g_.m.syscalltick != _g_.m.p.syscalltick {
+ _g_.m.mcache = _g_.m.p.ptr().mcache
+ _g_.m.p.ptr().m.set(_g_.m)
+ if _g_.m.syscalltick != _g_.m.p.ptr().syscalltick {
if trace.enabled {
// The p was retaken and then enter into syscall again (since _g_.m.syscalltick has changed).
// traceGoSysBlock for this syscall was already emitted,
// but here we effectively retake the p from the new syscall running on the same p.
systemstack(func() {
// Denote blocking of the new syscall.
- traceGoSysBlock(_g_.m.p)
+ traceGoSysBlock(_g_.m.p.ptr())
// Denote completion of the current syscall.
traceGoSysExit(0)
})
}
- _g_.m.p.syscalltick++
+ _g_.m.p.ptr().syscalltick++
}
return true
}
// Try to get any other idle P.
- oldp := _g_.m.p
+ oldp := _g_.m.p.ptr()
_g_.m.mcache = nil
- _g_.m.p = nil
- if sched.pidle != nil {
+ _g_.m.p = 0
+ if sched.pidle != 0 {
var ok bool
systemstack(func() {
ok = exitsyscallfast_pidle()
@@ -2101,7 +2096,7 @@
throw("newproc: function arguments too large for new goroutine")
}
- _p_ := _g_.m.p
+ _p_ := _g_.m.p.ptr()
newg := gfget(_p_)
if newg == nil {
newg = malg(_StackMin)
@@ -2184,7 +2179,7 @@
gp.stackguard0 = 0
}
- gp.schedlink = _p_.gfree
+ gp.schedlink.set(_p_.gfree)
_p_.gfree = gp
_p_.gfreecnt++
if _p_.gfreecnt >= 64 {
@@ -2192,8 +2187,8 @@
for _p_.gfreecnt >= 32 {
_p_.gfreecnt--
gp = _p_.gfree
- _p_.gfree = gp.schedlink
- gp.schedlink = sched.gfree
+ _p_.gfree = gp.schedlink.ptr()
+ gp.schedlink.set(sched.gfree)
sched.gfree = gp
sched.ngfree++
}
@@ -2211,16 +2206,16 @@
for _p_.gfreecnt < 32 && sched.gfree != nil {
_p_.gfreecnt++
gp = sched.gfree
- sched.gfree = gp.schedlink
+ sched.gfree = gp.schedlink.ptr()
sched.ngfree--
- gp.schedlink = _p_.gfree
+ gp.schedlink.set(_p_.gfree)
_p_.gfree = gp
}
unlock(&sched.gflock)
goto retry
}
if gp != nil {
- _p_.gfree = gp.schedlink
+ _p_.gfree = gp.schedlink.ptr()
_p_.gfreecnt--
if gp.stack.lo == 0 {
// Stack was deallocated in gfput. Allocate a new one.
@@ -2243,8 +2238,8 @@
for _p_.gfreecnt != 0 {
_p_.gfreecnt--
gp := _p_.gfree
- _p_.gfree = gp.schedlink
- gp.schedlink = sched.gfree
+ _p_.gfree = gp.schedlink.ptr()
+ gp.schedlink.set(sched.gfree)
sched.gfree = gp
sched.ngfree++
}
@@ -2453,10 +2448,10 @@
// This is especially important on windows, since all syscalls are cgo calls.
n = gentraceback(mp.curg.syscallpc, mp.curg.syscallsp, 0, mp.curg, 0, &stk[0], len(stk), nil, nil, 0)
}
- if GOOS == "windows" && n == 0 && mp.libcallg != nil && mp.libcallpc != 0 && mp.libcallsp != 0 {
+ if GOOS == "windows" && n == 0 && mp.libcallg != 0 && mp.libcallpc != 0 && mp.libcallsp != 0 {
// Libcall, i.e. runtime syscall on windows.
// Collect Go stack that leads to the call.
- n = gentraceback(mp.libcallpc, mp.libcallsp, 0, mp.libcallg, 0, &stk[0], len(stk), nil, nil, 0)
+ n = gentraceback(mp.libcallpc, mp.libcallsp, 0, mp.libcallg.ptr(), 0, &stk[0], len(stk), nil, nil, 0)
}
if n == 0 {
// If all of the above has failed, account it against abstract "System" or "GC".
@@ -2570,7 +2565,7 @@
for i := nprocs; i < old; i++ {
p := allp[i]
if trace.enabled {
- if p == getg().m.p {
+ if p == getg().m.p.ptr() {
// moving to p[0], pretend that we were descheduled
// and then scheduled again to keep the trace sane.
traceGoSched()
@@ -2584,9 +2579,9 @@
gp := p.runq[p.runqtail%uint32(len(p.runq))]
// push onto head of global queue
gp.schedlink = sched.runqhead
- sched.runqhead = gp
- if sched.runqtail == nil {
- sched.runqtail = gp
+ sched.runqhead.set(gp)
+ if sched.runqtail == 0 {
+ sched.runqtail.set(gp)
}
sched.runqsize++
}
@@ -2609,18 +2604,18 @@
}
_g_ := getg()
- if _g_.m.p != nil && _g_.m.p.id < nprocs {
+ if _g_.m.p != 0 && _g_.m.p.ptr().id < nprocs {
// continue to use the current P
- _g_.m.p.status = _Prunning
+ _g_.m.p.ptr().status = _Prunning
} else {
// release the current P and acquire allp[0]
- if _g_.m.p != nil {
- _g_.m.p.m = nil
+ if _g_.m.p != 0 {
+ _g_.m.p.ptr().m = 0
}
- _g_.m.p = nil
+ _g_.m.p = 0
_g_.m.mcache = nil
p := allp[0]
- p.m = nil
+ p.m = 0
p.status = _Pidle
acquirep(p)
if trace.enabled {
@@ -2630,15 +2625,15 @@
var runnablePs *p
for i := nprocs - 1; i >= 0; i-- {
p := allp[i]
- if _g_.m.p == p {
+ if _g_.m.p.ptr() == p {
continue
}
p.status = _Pidle
if p.runqhead == p.runqtail {
pidleput(p)
} else {
- p.m = mget()
- p.link = runnablePs
+ p.m.set(mget())
+ p.link.set(runnablePs)
runnablePs = p
}
}
@@ -2648,53 +2643,57 @@
}
// Associate p and the current m.
-// May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
func acquirep(_p_ *p) {
- _g_ := getg()
+ acquirep1(_p_)
- if _g_.m.p != nil || _g_.m.mcache != nil {
- throw("acquirep: already in go")
- }
- if _p_.m != nil || _p_.status != _Pidle {
- id := int32(0)
- if _p_.m != nil {
- id = _p_.m.id
- }
- print("acquirep: p->m=", _p_.m, "(", id, ") p->status=", _p_.status, "\n")
- throw("acquirep: invalid p state")
- }
- // _p_.mcache holds the mcache and _p_ is in allp, so WB can be eliminated
- setMcacheNoWriteBarrier(&_g_.m.mcache, _p_.mcache)
- // _p_ is in allp so WB can be eliminated
- setPNoWriteBarrier(&_g_.m.p, _p_)
- // m is in _g_.m and is reachable through allg, so WB can be eliminated
- setMNoWriteBarrier(&_p_.m, _g_.m)
- _p_.status = _Prunning
+ // have p; write barriers now allowed
+ _g_ := getg()
+ _g_.m.mcache = _p_.mcache
if trace.enabled {
traceProcStart()
}
}
+// May run during STW, so write barriers are not allowed.
+//go:nowritebarrier
+func acquirep1(_p_ *p) {
+ _g_ := getg()
+
+ if _g_.m.p != 0 || _g_.m.mcache != nil {
+ throw("acquirep: already in go")
+ }
+ if _p_.m != 0 || _p_.status != _Pidle {
+ id := int32(0)
+ if _p_.m != 0 {
+ id = _p_.m.ptr().id
+ }
+ print("acquirep: p->m=", _p_.m, "(", id, ") p->status=", _p_.status, "\n")
+ throw("acquirep: invalid p state")
+ }
+ _g_.m.p.set(_p_)
+ _p_.m.set(_g_.m)
+ _p_.status = _Prunning
+}
+
// Disassociate p and the current m.
func releasep() *p {
_g_ := getg()
- if _g_.m.p == nil || _g_.m.mcache == nil {
+ if _g_.m.p == 0 || _g_.m.mcache == nil {
throw("releasep: invalid arg")
}
- _p_ := _g_.m.p
- if _p_.m != _g_.m || _p_.mcache != _g_.m.mcache || _p_.status != _Prunning {
- print("releasep: m=", _g_.m, " m->p=", _g_.m.p, " p->m=", _p_.m, " m->mcache=", _g_.m.mcache, " p->mcache=", _p_.mcache, " p->status=", _p_.status, "\n")
+ _p_ := _g_.m.p.ptr()
+ if _p_.m.ptr() != _g_.m || _p_.mcache != _g_.m.mcache || _p_.status != _Prunning {
+ print("releasep: m=", _g_.m, " m->p=", _g_.m.p.ptr(), " p->m=", _p_.m, " m->mcache=", _g_.m.mcache, " p->mcache=", _p_.mcache, " p->status=", _p_.status, "\n")
throw("releasep: invalid p state")
}
if trace.enabled {
- traceProcStop(_g_.m.p)
+ traceProcStop(_g_.m.p.ptr())
}
- _g_.m.p = nil
+ _g_.m.p = 0
_g_.m.mcache = nil
- _p_.m = nil
+ _p_.m = 0
_p_.status = _Pidle
return _p_
}
@@ -2773,7 +2772,7 @@
if mp == nil {
newm(nil, _p_)
} else {
- mp.nextp = _p_
+ mp.nextp.set(_p_)
notewakeup(&mp.park)
}
return
@@ -2865,7 +2864,7 @@
if lastgc != 0 && unixnow-lastgc > forcegcperiod && atomicload(&forcegc.idle) != 0 {
lock(&forcegc.lock)
forcegc.idle = 0
- forcegc.g.schedlink = nil
+ forcegc.g.schedlink = 0
injectglist(forcegc.g)
unlock(&forcegc.lock)
}
@@ -2978,7 +2977,7 @@
// and will be indicated by the gp->status no longer being
// Grunning
func preemptone(_p_ *p) bool {
- mp := _p_.m
+ mp := _p_.m.ptr()
if mp == nil || mp == getg().m {
return false
}
@@ -3018,7 +3017,7 @@
if _p_ == nil {
continue
}
- mp := _p_.m
+ mp := _p_.m.ptr()
h := atomicload(&_p_.runqhead)
t := atomicload(&_p_.runqtail)
if detailed {
@@ -3047,7 +3046,7 @@
}
for mp := allm; mp != nil; mp = mp.alllink {
- _p_ := mp.p
+ _p_ := mp.p.ptr()
gp := mp.curg
lockedg := mp.lockedg
id1 := int32(-1)
@@ -3089,10 +3088,8 @@
// May run during STW, so write barriers are not allowed.
//go:nowritebarrier
func mput(mp *m) {
- // sched.midle is reachable via allm, so WB can be eliminated.
- setMNoWriteBarrier(&mp.schedlink, sched.midle)
- // mp is reachable via allm, so WB can be eliminated.
- setMNoWriteBarrier(&sched.midle, mp)
+ mp.schedlink = sched.midle
+ sched.midle.set(mp)
sched.nmidle++
checkdead()
}
@@ -3102,10 +3099,9 @@
// May run during STW, so write barriers are not allowed.
//go:nowritebarrier
func mget() *m {
- mp := sched.midle
+ mp := sched.midle.ptr()
if mp != nil {
- // mp.schedlink is reachable via mp, which is on allm, so WB can be eliminated.
- setMNoWriteBarrier(&sched.midle, mp.schedlink)
+ sched.midle = mp.schedlink
sched.nmidle--
}
return mp
@@ -3116,27 +3112,26 @@
// May run during STW, so write barriers are not allowed.
//go:nowritebarrier
func globrunqput(gp *g) {
- gp.schedlink = nil
- if sched.runqtail != nil {
- // gp is on allg, so these three WBs can be eliminated.
- setGNoWriteBarrier(&sched.runqtail.schedlink, gp)
+ gp.schedlink = 0
+ if sched.runqtail != 0 {
+ sched.runqtail.ptr().schedlink.set(gp)
} else {
- setGNoWriteBarrier(&sched.runqhead, gp)
+ sched.runqhead.set(gp)
}
- setGNoWriteBarrier(&sched.runqtail, gp)
+ sched.runqtail.set(gp)
sched.runqsize++
}
// Put a batch of runnable goroutines on the global runnable queue.
// Sched must be locked.
func globrunqputbatch(ghead *g, gtail *g, n int32) {
- gtail.schedlink = nil
- if sched.runqtail != nil {
- sched.runqtail.schedlink = ghead
+ gtail.schedlink = 0
+ if sched.runqtail != 0 {
+ sched.runqtail.ptr().schedlink.set(ghead)
} else {
- sched.runqhead = ghead
+ sched.runqhead.set(ghead)
}
- sched.runqtail = gtail
+ sched.runqtail.set(gtail)
sched.runqsize += n
}
@@ -3160,14 +3155,14 @@
sched.runqsize -= n
if sched.runqsize == 0 {
- sched.runqtail = nil
+ sched.runqtail = 0
}
- gp := sched.runqhead
+ gp := sched.runqhead.ptr()
sched.runqhead = gp.schedlink
n--
for ; n > 0; n-- {
- gp1 := sched.runqhead
+ gp1 := sched.runqhead.ptr()
sched.runqhead = gp1.schedlink
runqput(_p_, gp1)
}
@@ -3179,9 +3174,8 @@
// May run during STW, so write barriers are not allowed.
//go:nowritebarrier
func pidleput(_p_ *p) {
- // sched.pidle, _p_.link and _p_ are reachable via allp, so WB can be eliminated.
- setPNoWriteBarrier(&_p_.link, sched.pidle)
- setPNoWriteBarrier(&sched.pidle, _p_)
+ _p_.link = sched.pidle
+ sched.pidle.set(_p_)
xadd(&sched.npidle, 1) // TODO: fast atomic
}
@@ -3190,10 +3184,9 @@
// May run during STW, so write barriers are not allowed.
//go:nowritebarrier
func pidleget() *p {
- _p_ := sched.pidle
+ _p_ := sched.pidle.ptr()
if _p_ != nil {
- // _p_.link is reachable via a _p_ in allp, so WB can be eliminated.
- setPNoWriteBarrier(&sched.pidle, _p_.link)
+ sched.pidle = _p_.link
xadd(&sched.npidle, -1) // TODO: fast atomic
}
return _p_
@@ -3239,7 +3232,7 @@
// Link the goroutines.
for i := uint32(0); i < n; i++ {
- batch[i].schedlink = batch[i+1]
+ batch[i].schedlink.set(batch[i+1])
}
// Now put the batch on global queue.
@@ -3413,7 +3406,7 @@
mp := _g_.m
mp.locks++
- return int(mp.p.id)
+ return int(mp.p.ptr().id)
}
//go:nosplit
@@ -3458,7 +3451,7 @@
if i >= active_spin || ncpu <= 1 || gomaxprocs <= int32(sched.npidle+sched.nmspinning)+1 {
return false
}
- if p := getg().m.p; p.runqhead != p.runqtail {
+ if p := getg().m.p.ptr(); p.runqhead != p.runqtail {
return false
}
return true
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 3230d4e..a59d77d 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -87,8 +87,28 @@
data unsafe.Pointer
}
+// The guintptr, muintptr, and puintptr are all used to bypass write barriers.
+// It is particularly important to avoid write barriers when the current P has
+// been released, because the GC thinks the world is stopped, and an
+// unexpected write barrier would not be synchronized with the GC,
+// which can lead to a half-executed write barrier that has marked the object
+// but not queued it. If the GC skips the object and completes before the
+// queuing can occur, it will incorrectly free the object.
+//
+// We tried using special assignment functions invoked only when not
+// holding a running P, but then some updates to a particular memory
+// word went through write barriers and some did not. This breaks the
+// write barrier shadow checking mode, and it is also scary: better to have
+// a word that is completely ignored by the GC than to have one for which
+// only a few updates are ignored.
+//
+// Gs, Ms, and Ps are always reachable via true pointers in the
+// allgs, allm, and allp lists or (during allocation before they reach those lists)
+// from stack variables.
+
// A guintptr holds a goroutine pointer, but typed as a uintptr
-// to bypass write barriers. It is used in the Gobuf goroutine state.
+// to bypass write barriers. It is used in the Gobuf goroutine state
+// and in scheduling lists that are manipulated without a P.
//
// The Gobuf.g goroutine pointer is almost always updated by assembly code.
// In one of the few places it is updated by Go code - func save - it must be
@@ -107,41 +127,18 @@
// alternate arena. Using guintptr doesn't make that problem any worse.
type guintptr uintptr
-func (gp guintptr) ptr() *g {
- return (*g)(unsafe.Pointer(gp))
-}
+func (gp guintptr) ptr() *g { return (*g)(unsafe.Pointer(gp)) }
+func (gp *guintptr) set(g *g) { *gp = guintptr(unsafe.Pointer(g)) }
-// ps, ms, gs, and mcache are structures that must be manipulated at a level
-// lower than that of the normal Go language. For example the routine that
-// stops the world removes the p from the m structure informing the GC that
-// this P is stopped and then it moves the g to the global runnable queue.
-// If write barriers were allowed to happen at this point not only does
-// the GC think the thread is stopped but the underlying structures
-// like a p or m are not in a state that is not coherent enough to
-// support the write barrier actions.
-// This is particularly painful since a partially executed write barrier
-// may mark the object but be delinquent in informing the GC that the
-// object needs to be scanned.
+type puintptr uintptr
-// setGNoWriteBarriers does *gdst = gval without a write barrier.
-func setGNoWriteBarrier(gdst **g, gval *g) {
- *(*uintptr)(unsafe.Pointer(gdst)) = uintptr(unsafe.Pointer(gval))
-}
+func (pp puintptr) ptr() *p { return (*p)(unsafe.Pointer(pp)) }
+func (pp *puintptr) set(p *p) { *pp = puintptr(unsafe.Pointer(p)) }
-// setMNoWriteBarriers does *mdst = mval without a write barrier.
-func setMNoWriteBarrier(mdst **m, mval *m) {
- *(*uintptr)(unsafe.Pointer(mdst)) = uintptr(unsafe.Pointer(mval))
-}
+type muintptr uintptr
-// setPNoWriteBarriers does *pdst = pval without a write barrier.
-func setPNoWriteBarrier(pdst **p, pval *p) {
- *(*uintptr)(unsafe.Pointer(pdst)) = uintptr(unsafe.Pointer(pval))
-}
-
-// setMcacheNoWriteBarriers does *mcachedst = mcacheval without a write barrier.
-func setMcacheNoWriteBarrier(mcachedst **mcache, mcacheval *mcache) {
- *(*uintptr)(unsafe.Pointer(mcachedst)) = uintptr(unsafe.Pointer(mcacheval))
-}
+func (mp muintptr) ptr() *m { return (*m)(unsafe.Pointer(mp)) }
+func (mp *muintptr) set(m *m) { *mp = muintptr(unsafe.Pointer(m)) }
type gobuf struct {
// The offsets of sp, pc, and g are known to (hard-coded in) libmach.
@@ -224,7 +221,7 @@
goid int64
waitsince int64 // approx time when the g become blocked
waitreason string // if status==gwaiting
- schedlink *g
+ schedlink guintptr
preempt bool // preemption signal, duplicates stackguard0 = stackpreempt
paniconfault bool // panic (instead of crash) on unexpected fault address
preemptscan bool // preempted g does scan for gc
@@ -263,11 +260,11 @@
procid uint64 // for debuggers, but offset not hard-coded
gsignal *g // signal-handling g
tls [4]uintptr // thread-local storage (for x86 extern register)
- mstartfn uintptr // TODO: type as func(); note: this is a non-heap allocated func()
- curg *g // current running goroutine
- caughtsig *g // goroutine running during fatal signal
- p *p // attached p for executing go code (nil if not executing go code)
- nextp *p
+ mstartfn func()
+ curg *g // current running goroutine
+ caughtsig guintptr // goroutine running during fatal signal
+ p puintptr // attached p for executing go code (nil if not executing go code)
+ nextp puintptr
id int32
mallocing int32
throwing int32
@@ -286,7 +283,7 @@
ncgo int32 // number of cgo calls currently in progress
park note
alllink *m // on allm
- schedlink *m
+ schedlink muintptr
machport uint32 // return address for mach ipc (os x)
mcache *mcache
lockedg *g
@@ -315,7 +312,7 @@
libcall libcall
libcallpc uintptr // for cpu profiler
libcallsp uintptr
- libcallg *g
+ libcallg guintptr
//#endif
//#ifdef GOOS_solaris
perrno *int32 // pointer to tls errno
@@ -336,10 +333,10 @@
id int32
status uint32 // one of pidle/prunning/...
- link *p
- schedtick uint32 // incremented on every scheduler call
- syscalltick uint32 // incremented on every system call
- m *m // back-link to associated m (nil if idle)
+ link puintptr
+ schedtick uint32 // incremented on every scheduler call
+ syscalltick uint32 // incremented on every system call
+ m muintptr // back-link to associated m (nil if idle)
mcache *mcache
deferpool [5][]*_defer // pool of available defer structs of different sizes (see panic.go)
@@ -379,19 +376,19 @@
goidgen uint64
- midle *m // idle m's waiting for work
- nmidle int32 // number of idle m's waiting for work
- nmidlelocked int32 // number of locked m's waiting for work
- mcount int32 // number of m's that have been created
- maxmcount int32 // maximum number of m's allowed (or die)
+ midle muintptr // idle m's waiting for work
+ nmidle int32 // number of idle m's waiting for work
+ nmidlelocked int32 // number of locked m's waiting for work
+ mcount int32 // number of m's that have been created
+ maxmcount int32 // maximum number of m's allowed (or die)
- pidle *p // idle p's
+ pidle puintptr // idle p's
npidle uint32
nmspinning uint32
// Global runnable queue.
- runqhead *g
- runqtail *g
+ runqhead guintptr
+ runqtail guintptr
runqsize int32
// Global cache of dead G's.
diff --git a/src/runtime/signal_386.go b/src/runtime/signal_386.go
index b632995..f3c36cb 100644
--- a/src/runtime/signal_386.go
+++ b/src/runtime/signal_386.go
@@ -100,7 +100,7 @@
}
_g_.m.throwing = 1
- setGNoWriteBarrier(&_g_.m.caughtsig, gp)
+ _g_.m.caughtsig.set(gp)
startpanic()
if sig < uint32(len(sigtable)) {
diff --git a/src/runtime/signal_amd64x.go b/src/runtime/signal_amd64x.go
index 5dc9d80..182b16e 100644
--- a/src/runtime/signal_amd64x.go
+++ b/src/runtime/signal_amd64x.go
@@ -136,7 +136,7 @@
}
_g_.m.throwing = 1
- setGNoWriteBarrier(&_g_.m.caughtsig, gp)
+ _g_.m.caughtsig.set(gp)
if crashing == 0 {
startpanic()
diff --git a/src/runtime/signal_arm.go b/src/runtime/signal_arm.go
index 7d417fa..38d7181 100644
--- a/src/runtime/signal_arm.go
+++ b/src/runtime/signal_arm.go
@@ -95,7 +95,7 @@
}
_g_.m.throwing = 1
- setGNoWriteBarrier(&_g_.m.caughtsig, gp)
+ _g_.m.caughtsig.set(gp)
startpanic()
if sig < uint32(len(sigtable)) {
diff --git a/src/runtime/signal_arm64.go b/src/runtime/signal_arm64.go
index d1904de..dde3c7c 100644
--- a/src/runtime/signal_arm64.go
+++ b/src/runtime/signal_arm64.go
@@ -108,7 +108,7 @@
}
_g_.m.throwing = 1
- setGNoWriteBarrier(&_g_.m.caughtsig, gp)
+ _g_.m.caughtsig.set(gp)
startpanic()
if sig < uint32(len(sigtable)) {
diff --git a/src/runtime/signal_ppc64x.go b/src/runtime/signal_ppc64x.go
index 018d7d6..04d8cfc 100644
--- a/src/runtime/signal_ppc64x.go
+++ b/src/runtime/signal_ppc64x.go
@@ -113,7 +113,7 @@
}
_g_.m.throwing = 1
- setGNoWriteBarrier(&_g_.m.caughtsig, gp)
+ _g_.m.caughtsig.set(gp)
startpanic()
if sig < uint32(len(sigtable)) {
diff --git a/src/runtime/stack1.go b/src/runtime/stack1.go
index 5f28d28..db7e3cb 100644
--- a/src/runtime/stack1.go
+++ b/src/runtime/stack1.go
@@ -680,7 +680,7 @@
// it needs a lock held by the goroutine), that small preemption turns
// into a real deadlock.
if preempt {
- if thisg.m.locks != 0 || thisg.m.mallocing != 0 || thisg.m.preemptoff != "" || thisg.m.p.status != _Prunning {
+ if thisg.m.locks != 0 || thisg.m.mallocing != 0 || thisg.m.preemptoff != "" || thisg.m.p.ptr().status != _Prunning {
// Let the goroutine keep running for now.
// gp->preempt is set, so it will be preempted next time.
gp.stackguard0 = gp.stack.lo + _StackGuard
@@ -724,7 +724,7 @@
if gp == thisg.m.g0 {
throw("runtime: preempt g0")
}
- if thisg.m.p == nil && thisg.m.locks == 0 {
+ if thisg.m.p == 0 && thisg.m.locks == 0 {
throw("runtime: g is running but p is not")
}
if gp.preemptscan {
diff --git a/src/runtime/trace.go b/src/runtime/trace.go
index a149799..e0eb7d8 100644
--- a/src/runtime/trace.go
+++ b/src/runtime/trace.go
@@ -506,7 +506,7 @@
// traceAcquireBuffer returns trace buffer to use and, if necessary, locks it.
func traceAcquireBuffer() (mp *m, pid int32, bufp **traceBuf) {
mp = acquirem()
- if p := mp.p; p != nil {
+ if p := mp.p.ptr(); p != nil {
return mp, p.id, &p.tracebuf
}
lock(&trace.bufLock)
@@ -732,7 +732,7 @@
// to handle this we temporary employ the P.
mp := acquirem()
oldp := mp.p
- mp.p = pp
+ mp.p.set(pp)
traceEvent(traceEvProcStop, -1)
mp.p = oldp
releasem(mp)
@@ -806,7 +806,7 @@
// to handle this we temporary employ the P.
mp := acquirem()
oldp := mp.p
- mp.p = pp
+ mp.p.set(pp)
traceEvent(traceEvGoSysBlock, -1)
mp.p = oldp
releasem(mp)
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index b6f4374..91541fa 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -528,7 +528,7 @@
func showframe(f *_func, gp *g) bool {
g := getg()
- if g.m.throwing > 0 && gp != nil && (gp == g.m.curg || gp == g.m.caughtsig) {
+ if g.m.throwing > 0 && gp != nil && (gp == g.m.curg || gp == g.m.caughtsig.ptr()) {
return true
}
traceback := gotraceback(nil)
