diff options
Diffstat (limited to 'lib/system/gc2.nim')
| -rw-r--r-- | lib/system/gc2.nim | 140 |
1 files changed, 70 insertions, 70 deletions
diff --git a/lib/system/gc2.nim b/lib/system/gc2.nim index 015e08c9e..4ca0d144f 100644 --- a/lib/system/gc2.nim +++ b/lib/system/gc2.nim @@ -37,19 +37,19 @@ const rcAlive = 0b00000 # object is reachable. # color *black* in the original paper - + rcCycleCandidate = 0b00001 # possible root of a cycle. *purple* rcDecRefApplied = 0b00010 # the first dec-ref phase of the # collector was already applied to this # object. *gray* - + rcMaybeDead = 0b00011 # this object is a candidate for deletion # during the collect cycles algorithm. # *white*. - + rcReallyDead = 0b00100 # this is proved to be garbage - + rcRetiredBuffer = 0b00101 # this is a seq or string buffer that # was replaced by a resize operation. # see growObj for details @@ -80,14 +80,14 @@ const # The bit must also be set for new objects that are not rc1 and it must be # examined in the decref loop in collectCycles. # XXX: not implemented yet as tests didn't show any improvement from this - + MarkingSkipsAcyclicObjects = true - # Acyclic objects can be safely ignored in the mark and scan phases, + # Acyclic objects can be safely ignored in the mark and scan phases, # because they cannot contribute to the internal count. # XXX: if we generate specialized `markCyclic` and `markAcyclic` # procs we can further optimize this as there won't be need for any # checks in the code - + MinimumStackMarking = false # Try to scan only the user stack and ignore the part of the stack # belonging to the GC itself. see setStackTop for further info. @@ -110,9 +110,9 @@ type maxThreshold: int # max threshold that has been set maxStackSize: int # max stack size maxStackCells: int # max stack cells in ``decStack`` - cycleTableSize: int # max entries in cycle table + cycleTableSize: int # max entries in cycle table maxPause: int64 # max measured GC pause in nanoseconds - + GcHeap {.final, pure.} = object # this contains the zero count and # non-zero count table stackBottom: pointer @@ -124,7 +124,7 @@ type tempStack: CellSeq # temporary stack for recursion elimination freeStack: CellSeq # objects ready to be freed recGcLock: int # prevent recursion via finalizers; no thread lock - cycleRootsTrimIdx: int # Trimming is a light-weight collection of the + cycleRootsTrimIdx: int # Trimming is a light-weight collection of the # cycle roots table that uses a cheap linear scan # to find only possitively dead objects. # One strategy is to perform it only for new objects @@ -143,11 +143,11 @@ var when not defined(useNimRtl): instantiateForRegion(gch.region) -template acquire(gch: GcHeap) = +template acquire(gch: GcHeap) = when hasThreadSupport and hasSharedHeap: AcquireSys(HeapLock) -template release(gch: GcHeap) = +template release(gch: GcHeap) = when hasThreadSupport and hasSharedHeap: releaseSys(HeapLock) @@ -185,7 +185,7 @@ when debugGC: of rcRetiredBuffer: return "retired" of rcReallyDead: return "dead" else: return "unknown?" - + proc inCycleRootsStr(c: PCell): cstring = if c.isBitUp(rcInCycleRoots): result = "cycleroot" else: result = "" @@ -225,7 +225,7 @@ template setStackTop(gch) = template addCycleRoot(cycleRoots: var CellSeq, c: PCell) = if c.color != rcCycleCandidate: c.setColor rcCycleCandidate - + # the object may be buffered already. for example, consider: # decref; incref; decref if c.isBitDown(rcInCycleRoots): @@ -307,7 +307,7 @@ when traceGC: let startLen = gch.tempStack.len c.forAllChildren waPush - + while startLen != gch.tempStack.len: dec gch.tempStack.len var c = gch.tempStack.d[gch.tempStack.len] @@ -331,7 +331,7 @@ when traceGC: if c.isBitUp(rcMarkBit) and not isMarked: writecell("cyclic cell", cell) cprintf "Weight %d\n", cell.computeCellWeight - + proc writeLeakage(onlyRoots: bool) = if onlyRoots: for c in elements(states[csAllocated]): @@ -356,7 +356,7 @@ template WithHeapLock(blk: stmt): stmt = blk when hasThreadSupport and hasSharedHeap: ReleaseSys(HeapLock) -proc rtlAddCycleRoot(c: PCell) {.rtl, inl.} = +proc rtlAddCycleRoot(c: PCell) {.rtl, inl.} = # we MUST access gch as a global here, because this crosses DLL boundaries! WithHeapLock: addCycleRoot(gch.cycleRoots, c) @@ -423,7 +423,7 @@ template doIncRef(cc: PCell, elif IncRefRemovesCandidates: c.setColor rcAlive # XXX: this is not really atomic enough! - + proc nimGCref(p: pointer) {.compilerProc, inline.} = doIncRef(usrToCell(p)) proc nimGCunref(p: pointer) {.compilerProc, inline.} = doDecRef(usrToCell(p)) @@ -449,7 +449,7 @@ proc asgnRef(dest: PPointer, src: pointer) {.compilerProc, inline.} = doAsgnRef(dest, src, LocalHeap, MaybeCyclic) proc asgnRefNoCycle(dest: PPointer, src: pointer) {.compilerProc, inline.} = - # the code generator calls this proc if it is known at compile time that no + # the code generator calls this proc if it is known at compile time that no # cycle is possible. doAsgnRef(dest, src, LocalHeap, Acyclic) @@ -509,7 +509,7 @@ proc forAllSlotsAux(dest: pointer, n: ptr TNimNode, op: WalkOp) = if n.sons[i].typ.kind in {tyRef, tyString, tySequence}: doOperation(cast[PPointer](d +% n.sons[i].offset)[], op) else: - forAllChildrenAux(cast[pointer](d +% n.sons[i].offset), + forAllChildrenAux(cast[pointer](d +% n.sons[i].offset), n.sons[i].typ, op) else: forAllSlotsAux(dest, n.sons[i], op) @@ -557,7 +557,7 @@ proc addNewObjToZCT(res: PCell, gch: var GcHeap) {.inline.} = # we check the last 8 entries (cache line) for a slot that could be reused. # In 63% of all cases we succeed here! But we have to optimize the heck # out of this small linear search so that ``newObj`` is not slowed down. - # + # # Slots to try cache hit # 1 32% # 4 59% @@ -602,7 +602,7 @@ proc rawNewObj(typ: PNimType, size: int, gch: var GcHeap, rc1 = false): pointer acquire(gch) sysAssert(allocInv(gch.region), "rawNewObj begin") sysAssert(typ.kind in {tyRef, tyString, tySequence}, "newObj: 1") - + collectCT(gch) sysAssert(allocInv(gch.region), "rawNewObj after collect") @@ -610,16 +610,16 @@ proc rawNewObj(typ: PNimType, size: int, gch: var GcHeap, rc1 = false): pointer sysAssert(allocInv(gch.region), "rawNewObj after rawAlloc") sysAssert((cast[ByteAddress](res) and (MemAlign-1)) == 0, "newObj: 2") - + res.typ = typ - + when trackAllocationSource and not hasThreadSupport: if framePtr != nil and framePtr.prev != nil and framePtr.prev.prev != nil: res.filename = framePtr.prev.prev.filename res.line = framePtr.prev.prev.line else: res.filename = "nofile" - + if rc1: res.refcount = rcIncrement # refcount is 1 else: @@ -631,9 +631,9 @@ proc rawNewObj(typ: PNimType, size: int, gch: var GcHeap, rc1 = false): pointer res.setBit(rcInCycleRoots) res.setColor rcCycleCandidate gch.cycleRoots.add res - + sysAssert(isAllocatedPtr(gch.region, res), "newObj: 3") - + when logGC: writeCell("new cell", res) gcTrace(res, csAllocated) release(gch) @@ -711,9 +711,9 @@ proc growObj(old: pointer, newsize: int, gch: var GcHeap): pointer = var res = cast[PCell](rawAlloc(gch.region, newsize + sizeof(Cell))) var elemSize = if ol.typ.kind != tyString: ol.typ.base.size else: 1 - + var oldsize = cast[PGenericSeq](old).len*elemSize + GenericSeqSize - + # XXX: This should happen outside # call user-defined move code # call user-defined default constructor @@ -723,24 +723,24 @@ proc growObj(old: pointer, newsize: int, gch: var GcHeap): pointer = sysAssert((cast[ByteAddress](res) and (MemAlign-1)) == 0, "growObj: 3") sysAssert(res.refcount shr rcShift <=% 1, "growObj: 4") - + when false: if ol.isBitUp(rcZct): var j = gch.zct.len-1 var d = gch.zct.d - while j >= 0: + while j >= 0: if d[j] == ol: d[j] = res break dec(j) - + if ol.isBitUp(rcInCycleRoots): for i in 0 .. <gch.cycleRoots.len: if gch.cycleRoots.d[i] == ol: eraseAt(gch.cycleRoots, i) freeCell(gch, ol) - + else: # the new buffer inherits the GC state of the old one if res.isBitUp(rcZct): gch.zct.add res @@ -787,12 +787,12 @@ proc doOperation(p: pointer, op: WalkOp) = var c: PCell = usrToCell(p) sysAssert(c != nil, "doOperation: 1") gch.tempStack.add c - + proc nimGCvisit(d: pointer, op: int) {.compilerRtl.} = doOperation(d, WalkOp(op)) type - RecursionType = enum + RecursionType = enum FromChildren, FromRoot {.deprecated: [TRecursionType: RecursionType].} @@ -838,14 +838,14 @@ proc collectCycles(gch: var GcHeap) = let startLen = gch.tempStack.len cell.setColor rcAlive cell.forAllChildren waPush - + while startLen != gch.tempStack.len: dec gch.tempStack.len var c = gch.tempStack.d[gch.tempStack.len] if c.color != rcAlive: c.setColor rcAlive c.forAllChildren waPush - + template earlyMarkAlive(stackRoots) = # This marks all objects reachable from the stack as alive before any # of the other stages is executed. Such objects cannot be garbage and @@ -856,7 +856,7 @@ proc collectCycles(gch: var GcHeap) = earlyMarkAliveRec(c) earlyMarkAlive(gch.decStack) - + when CollectCyclesStats: let tAfterEarlyMarkAlive = getTicks() @@ -864,7 +864,7 @@ proc collectCycles(gch: var GcHeap) = let startLen = gch.tempStack.len cell.setColor rcDecRefApplied cell.forAllChildren waPush - + while startLen != gch.tempStack.len: dec gch.tempStack.len var c = gch.tempStack.d[gch.tempStack.len] @@ -876,7 +876,7 @@ proc collectCycles(gch: var GcHeap) = if c.color != rcDecRefApplied: c.setColor rcDecRefApplied c.forAllChildren waPush - + template markRoots(roots) = var i = 0 while i < roots.len: @@ -885,34 +885,34 @@ proc collectCycles(gch: var GcHeap) = inc i else: roots.trimAt i - + markRoots(gch.cycleRoots) - + when CollectCyclesStats: let tAfterMark = getTicks() c_printf "COLLECT CYCLES %d: %d/%d\n", gcCollectionIdx, gch.cycleRoots.len, l0 - + template recursiveMarkAlive(cell) = let startLen = gch.tempStack.len cell.setColor rcAlive cell.forAllChildren waPush - + while startLen != gch.tempStack.len: dec gch.tempStack.len var c = gch.tempStack.d[gch.tempStack.len] if ignoreObject(c): continue inc c.refcount, rcIncrement inc increfs - + if c.color != rcAlive: c.setColor rcAlive c.forAllChildren waPush - + template scanRoots(roots) = for i in 0 .. <roots.len: let startLen = gch.tempStack.len gch.tempStack.add roots.d[i] - + while startLen != gch.tempStack.len: dec gch.tempStack.len var c = gch.tempStack.d[gch.tempStack.len] @@ -928,9 +928,9 @@ proc collectCycles(gch: var GcHeap) = c.setColor rcMaybeDead inc maybedeads c.forAllChildren waPush - + scanRoots(gch.cycleRoots) - + when CollectCyclesStats: let tAfterScan = getTicks() @@ -941,7 +941,7 @@ proc collectCycles(gch: var GcHeap) = let startLen = gch.tempStack.len gch.tempStack.add c - + while startLen != gch.tempStack.len: dec gch.tempStack.len var c = gch.tempStack.d[gch.tempStack.len] @@ -965,7 +965,7 @@ proc collectCycles(gch: var GcHeap) = freeCell(gch, gch.freeStack.d[i]) collectDead(gch.cycleRoots) - + when CollectCyclesStats: let tFinal = getTicks() cprintf "times:\n early mark alive: %d ms\n mark: %d ms\n scan: %d ms\n collect: %d ms\n decrefs: %d\n increfs: %d\n marked dead: %d\n collected: %d\n", @@ -986,7 +986,7 @@ proc collectCycles(gch: var GcHeap) = when MarkingSkipsAcyclicObjects: # Collect the acyclic objects that became unreachable due to collected - # cyclic objects. + # cyclic objects. discard collectZCT(gch) # collectZCT may add new cycle candidates and we may decide to loop here # if gch.cycleRoots.len > 0: repeat @@ -1030,12 +1030,12 @@ proc gcMark(gch: var GcHeap, p: pointer) {.inline.} = add(gch.decStack, cell) sysAssert(allocInv(gch.region), "gcMark end") -proc markThreadStacks(gch: var GcHeap) = +proc markThreadStacks(gch: var GcHeap) = when hasThreadSupport and hasSharedHeap: {.error: "not fully implemented".} var it = threadList while it != nil: - # mark registers: + # mark registers: for i in 0 .. high(it.registers): gcMark(gch, it.registers[i]) var sp = cast[ByteAddress](it.stackBottom) var max = cast[ByteAddress](it.stackTop) @@ -1121,7 +1121,7 @@ elif stackIncreases: var b = cast[ByteAddress](stackTop) var x = cast[ByteAddress](p) result = a <=% x and x <=% b - + proc markStackAndRegisters(gch: var GcHeap) {.noinline, cdecl.} = var registers: C_JmpBuf if c_setjmp(registers) == 0'i32: # To fill the C stack with registers. @@ -1156,7 +1156,7 @@ else: # mark the registers var jmpbufPtr = cast[ByteAddress](addr(registers)) var jmpbufEnd = jmpbufPtr +% jmpbufSize - + while jmpbufPtr <=% jmpbufEnd: gcMark(gch, cast[PPointer](jmpbufPtr)[]) jmpbufPtr = jmpbufPtr +% sizeof(pointer) @@ -1218,18 +1218,18 @@ proc releaseCell(gch: var GcHeap, cell: PCell) = proc collectZCT(gch: var GcHeap): bool = const workPackage = 100 var L = addr(gch.zct.len) - + when withRealtime: var steps = workPackage var t0: Ticks if gch.maxPause > 0: t0 = getticks() - + while L[] > 0: var c = gch.zct.d[0] sysAssert c.isBitUp(rcZct), "collectZCT: rcZct missing!" sysAssert(isAllocatedPtr(gch.region, c), "collectZCT: isAllocatedPtr") - - # remove from ZCT: + + # remove from ZCT: c.clearBit(rcZct) gch.zct.d[0] = gch.zct.d[L[] - 1] dec(L[]) @@ -1237,7 +1237,7 @@ proc collectZCT(gch: var GcHeap): bool = if c.refcount <% rcIncrement: # It may have a RC > 0, if it is in the hardware stack or # it has not been removed yet from the ZCT. This is because - # ``incref`` does not bother to remove the cell from the ZCT + # ``incref`` does not bother to remove the cell from the ZCT # as this might be too slow. # In any case, it should be removed from the ZCT. But not # freed. **KEEP THIS IN MIND WHEN MAKING THIS INCREMENTAL!** @@ -1252,7 +1252,7 @@ proc collectZCT(gch: var GcHeap): bool = steps = workPackage if gch.maxPause > 0: let duration = getticks() - t0 - # the GC's measuring is not accurate and needs some cleanup actions + # the GC's measuring is not accurate and needs some cleanup actions # (stack unmarking), so subtract some short amount of time in to # order to miss deadlines less often: if duration >= gch.maxPause - 50_000: @@ -1269,7 +1269,7 @@ proc unmarkStackAndRegisters(gch: var GcHeap) = # XXX: just call doDecRef? var c = d[i] sysAssert c.typ != nil, "unmarkStackAndRegisters 2" - + if c.color == rcRetiredBuffer: continue @@ -1278,7 +1278,7 @@ proc unmarkStackAndRegisters(gch: var GcHeap) = # the object survived only because of a stack reference # it still doesn't have heap references addZCT(gch.zct, c) - + if canbeCycleRoot(c): # any cyclic object reachable from the stack can be turned into # a leak if it's orphaned through the stack reference @@ -1293,7 +1293,7 @@ proc collectCTBody(gch: var GcHeap) = let t0 = getticks() when debugGC: inc gcCollectionIdx sysAssert(allocInv(gch.region), "collectCT: begin") - + gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize()) sysAssert(gch.decStack.len == 0, "collectCT") prepareForInteriorPointerChecking(gch.region) @@ -1312,7 +1312,7 @@ proc collectCTBody(gch: var GcHeap) = gch.stat.maxThreshold = max(gch.stat.maxThreshold, gch.cycleThreshold) unmarkStackAndRegisters(gch) sysAssert(allocInv(gch.region), "collectCT: end") - + when withRealtime: let duration = getticks() - t0 gch.stat.maxPause = max(gch.stat.maxPause, duration) @@ -1322,7 +1322,7 @@ proc collectCTBody(gch: var GcHeap) = proc collectCT(gch: var GcHeap) = if (gch.zct.len >= ZctThreshold or (cycleGC and - getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) and + getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) and gch.recGcLock == 0: collectCTBody(gch) @@ -1337,7 +1337,7 @@ when withRealtime: acquire(gch) gch.maxPause = us.toNano if (gch.zct.len >= ZctThreshold or (cycleGC and - getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) or + getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) or strongAdvice: collectCTBody(gch) release(gch) @@ -1345,13 +1345,13 @@ when withRealtime: proc GC_step*(us: int, strongAdvice = false) = GC_step(gch, us, strongAdvice) when not defined(useNimRtl): - proc GC_disable() = + proc GC_disable() = when hasThreadSupport and hasSharedHeap: discard atomicInc(gch.recGcLock, 1) else: inc(gch.recGcLock) proc GC_enable() = - if gch.recGcLock > 0: + if gch.recGcLock > 0: when hasThreadSupport and hasSharedHeap: discard atomicDec(gch.recGcLock, 1) else: |