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runtime: rename var checkmark to checkmarkphase

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The old name was too ambiguous (is it a verb?  is it a predicate?  is
it a constant?) and too close to debug.gccheckmark.  Hopefully the new
name conveys that this variable indicates that we are currently doing
mark checking.

Change-Id: I031cd48b0906cdc7774f5395281d3aeeb8ef3ec9
Reviewed-on: https://go-review.googlesource.com/2656
Reviewed-by: Rick Hudson <rlh@golang.org>
This commit is contained in:
Austin Clements 2015-01-12 13:45:40 -05:00
parent aae0f074c0
commit ea4f14cf2b
1 changed files with 23 additions and 23 deletions
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46
src/runtime/mgc.go
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@ -233,10 +233,10 @@ func have_cgo_allocate() bool {
// there are no more pointers in the object. This information is held
// in the second nibble.
// When marking an object if the bool checkmark is true one uses the above
// When marking an object if the bool checkmarkphase is true one uses the above
// encoding, otherwise one uses the bitMarked bit in the lower two bits
// of the nibble.
var checkmark = false
var checkmarkphase = false
// inheap reports whether b is a pointer into a (potentially dead) heap object.
// It returns false for pointers into stack spans.
@ -380,7 +380,7 @@ func gcmarknewobject_m(obj uintptr) {
if gcphase != _GCmarktermination {
throw("marking new object while not in mark termination phase")
}
if checkmark { // The world should be stopped so this should not happen.
if checkmarkphase { // The world should be stopped so this should not happen.
throw("gcmarknewobject called while doing checkmark")
}
@ -408,7 +408,7 @@ func greyobject(obj uintptr, base, off uintptr, mbits *markbits, wbuf *workbuf)
throw("greyobject: obj not pointer-aligned")
}
if checkmark {
if checkmarkphase {
if !ismarked(mbits) {
print("runtime:greyobject: checkmarks finds unexpected unmarked object obj=", hex(obj), ", mbits->bits=", hex(mbits.bits), " *mbits->bitp=", hex(*mbits.bitp), "\n")
print("runtime: found obj at *(", hex(base), "+", hex(off), ")\n")
@ -452,7 +452,7 @@ func greyobject(obj uintptr, base, off uintptr, mbits *markbits, wbuf *workbuf)
atomicor8(mbits.bitp, bitMarked<<mbits.shift)
}
if !checkmark && (mbits.xbits>>(mbits.shift+2))&_BitsMask == _BitsDead {
if !checkmarkphase && (mbits.xbits>>(mbits.shift+2))&_BitsMask == _BitsDead {
return wbuf // noscan object
}
@ -534,7 +534,7 @@ func scanobject(b, n uintptr, ptrmask *uint8, wbuf *workbuf) *workbuf {
}
if bits&_BitsPointer != _BitsPointer {
print("gc checkmark=", checkmark, " b=", hex(b), " ptrmask=", ptrmask, " mbits.bitp=", mbits.bitp, " mbits.xbits=", hex(mbits.xbits), " bits=", hex(bits), "\n")
print("gc checkmarkphase=", checkmarkphase, " b=", hex(b), " ptrmask=", ptrmask, " mbits.bitp=", mbits.bitp, " mbits.xbits=", hex(mbits.xbits), " bits=", hex(bits), "\n")
throw("unexpected garbage collection bits")
}
@ -546,7 +546,7 @@ func scanobject(b, n uintptr, ptrmask *uint8, wbuf *workbuf) *workbuf {
continue
}
if mheap_.shadow_enabled && debug.wbshadow >= 2 && debug.gccheckmark > 0 && checkmark {
if mheap_.shadow_enabled && debug.wbshadow >= 2 && debug.gccheckmark > 0 && checkmarkphase {
checkwbshadow((*uintptr)(unsafe.Pointer(b + i)))
}
@ -682,7 +682,7 @@ func markroot(desc *parfor, i uint32) {
if s.state != mSpanInUse {
continue
}
if !checkmark && s.sweepgen != sg {
if !checkmarkphase && s.sweepgen != sg {
// sweepgen was updated (+2) during non-checkmark GC pass
print("sweep ", s.sweepgen, " ", sg, "\n")
throw("gc: unswept span")
@ -1038,7 +1038,7 @@ func shaded(slot uintptr) bool {
return true
}
if checkmark {
if checkmarkphase {
return ischeckmarked(&mbits)
}
@ -1274,7 +1274,7 @@ func mSpan_EnsureSwept(s *mspan) {
// caller takes care of it.
//TODO go:nowritebarrier
func mSpan_Sweep(s *mspan, preserve bool) bool {
if checkmark {
if checkmarkphase {
throw("MSpan_Sweep: checkmark only runs in STW and after the sweep")
}
@ -1735,14 +1735,14 @@ func clearcheckmarkbitsspan(s *mspan) {
// 10 - BitsPointer
// 11 - unused, for us BitsPointerMarked
//
// When called to prepare for the checkmark phase (checkmark==1),
// When called to prepare for the checkmark phase (checkmarkphase==true),
// we change BitsDead to BitsScalar, so that there are no BitsScalarMarked
// type bits anywhere.
//
// The checkmark phase marks by changing BitsScalar to BitsScalarMarked
// and BitsPointer to BitsPointerMarked.
//
// When called to clean up after the checkmark phase (checkmark==0),
// When called to clean up after the checkmark phase (checkmarkphase==false),
// we unmark by changing BitsScalarMarked back to BitsScalar and
// BitsPointerMarked back to BitsPointer.
//
@ -1778,7 +1778,7 @@ func clearcheckmarkbitsspan(s *mspan) {
throw("missing bitBoundary")
}
b := (*bitp & bitPtrMask) >> 2
if !checkmark && (b == _BitsScalar || b == _BitsScalarMarked) {
if !checkmarkphase && (b == _BitsScalar || b == _BitsScalarMarked) {
*bitp &^= 0x0c // convert to _BitsDead
} else if b == _BitsScalarMarked || b == _BitsPointerMarked {
*bitp &^= _BitsCheckMarkXor << 2
@ -1788,7 +1788,7 @@ func clearcheckmarkbitsspan(s *mspan) {
throw("missing bitBoundary")
}
b = ((*bitp >> gcBits) & bitPtrMask) >> 2
if !checkmark && (b == _BitsScalar || b == _BitsScalarMarked) {
if !checkmarkphase && (b == _BitsScalar || b == _BitsScalarMarked) {
*bitp &^= 0xc0 // convert to _BitsDead
} else if b == _BitsScalarMarked || b == _BitsPointerMarked {
*bitp &^= _BitsCheckMarkXor << (2 + gcBits)
@ -1802,12 +1802,12 @@ func clearcheckmarkbitsspan(s *mspan) {
}
b := (*bitp & bitPtrMask) >> 2
if checkmark && b == _BitsDead {
if checkmarkphase && b == _BitsDead {
// move BitsDead into second word.
// set bits to BitsScalar in preparation for checkmark phase.
*bitp &^= 0xc0
*bitp |= _BitsScalar << 2
} else if !checkmark && (b == _BitsScalar || b == _BitsScalarMarked) && *bitp&0xc0 == 0 {
} else if !checkmarkphase && (b == _BitsScalar || b == _BitsScalarMarked) && *bitp&0xc0 == 0 {
// Cleaning up after checkmark phase.
// First word is scalar or dead (we forgot)
// and second word is dead.
@ -1847,13 +1847,13 @@ func gccheckmark_m(startTime int64, eagersweep bool) {
return
}
if checkmark {
throw("gccheckmark_m, entered with checkmark already true")
if checkmarkphase {
throw("gccheckmark_m, entered with checkmarkphase already true")
}
checkmark = true
checkmarkphase = true
clearcheckmarkbits() // Converts BitsDead to BitsScalar.
gc_m(startTime, eagersweep) // turns off checkmark + calls clearcheckmarkbits
gc_m(startTime, eagersweep) // turns off checkmarkphase + calls clearcheckmarkbits
}
//go:nowritebarrier
@ -1963,7 +1963,7 @@ func gc(start_time int64, eagersweep bool) {
t1 = nanotime()
}
if !checkmark {
if !checkmarkphase {
// TODO(austin) This is a noop beceause we should
// already have swept everything to the current
// sweepgen.
@ -2088,12 +2088,12 @@ func gc(start_time int64, eagersweep bool) {
}
if debug.gccheckmark > 0 {
if !checkmark {
if !checkmarkphase {
// first half of two-pass; don't set up sweep
unlock(&mheap_.lock)
return
}
checkmark = false // done checking marks
checkmarkphase = false // done checking marks
clearcheckmarkbits()
}