diff options
Diffstat (limited to 'lib/system/orc.nim')
| -rw-r--r-- | lib/system/orc.nim | 92 |
1 files changed, 69 insertions, 23 deletions
diff --git a/lib/system/orc.nim b/lib/system/orc.nim index 83b983ee1..c02a24989 100644 --- a/lib/system/orc.nim +++ b/lib/system/orc.nim @@ -81,10 +81,14 @@ proc trace(s: Cell; desc: PNimTypeV2; j: var GcEnv) {.inline.} = include threadids -when logOrc: +when logOrc or orcLeakDetector: proc writeCell(msg: cstring; s: Cell; desc: PNimTypeV2) = - cfprintf(cstderr, "%s %s %ld root index: %ld; RC: %ld; color: %ld; thread: %ld\n", - msg, desc.name, s.refId, s.rootIdx, s.rc shr rcShift, s.color, getThreadId()) + when orcLeakDetector: + cfprintf(cstderr, "%s %s file: %s:%ld; color: %ld; thread: %ld\n", + msg, desc.name, s.filename, s.line, s.color, getThreadId()) + else: + cfprintf(cstderr, "%s %s %ld root index: %ld; RC: %ld; color: %ld; thread: %ld\n", + msg, desc.name, s.refId, s.rootIdx, s.rc shr rcShift, s.color, getThreadId()) proc free(s: Cell; desc: PNimTypeV2) {.inline.} = when traceCollector: @@ -142,7 +146,7 @@ proc unregisterCycle(s: Cell) = let idx = s.rootIdx-1 when false: if idx >= roots.len or idx < 0: - cprintf("[Bug!] %ld\n", idx) + cprintf("[Bug!] %ld %ld\n", idx, roots.len) rawQuit 1 roots.d[idx] = roots.d[roots.len-1] roots.d[idx][0].rootIdx = idx+1 @@ -299,6 +303,14 @@ proc collectColor(s: Cell; desc: PNimTypeV2; col: int; j: var GcEnv) = t.setColor(colBlack) trace(t, desc, j) +const + defaultThreshold = when defined(nimFixedOrc): 10_000 else: 128 + +when defined(nimStressOrc): + const rootsThreshold = 10 # broken with -d:nimStressOrc: 10 and for havlak iterations 1..8 +else: + var rootsThreshold {.threadvar.}: int + proc collectCyclesBacon(j: var GcEnv; lowMark: int) = # pretty direct translation from # https://researcher.watson.ibm.com/researcher/files/us-bacon/Bacon01Concurrent.pdf @@ -337,20 +349,28 @@ proc collectCyclesBacon(j: var GcEnv; lowMark: int) = s.rootIdx = 0 collectColor(s, roots.d[i][1], colToCollect, j) + # Bug #22927: `free` calls destructors which can append to `roots`. + # We protect against this here by setting `roots.len` to 0 and also + # setting the threshold so high that no cycle collection can be triggered + # until we are out of this critical section: + when not defined(nimStressOrc): + let oldThreshold = rootsThreshold + rootsThreshold = high(int) + roots.len = 0 + for i in 0 ..< j.toFree.len: + when orcLeakDetector: + writeCell("CYCLIC OBJECT FREED", j.toFree.d[i][0], j.toFree.d[i][1]) free(j.toFree.d[i][0], j.toFree.d[i][1]) + when not defined(nimStressOrc): + rootsThreshold = oldThreshold + inc j.freed, j.toFree.len deinit j.toFree - #roots.len = 0 - -const - defaultThreshold = when defined(nimFixedOrc): 10_000 else: 128 -when defined(nimStressOrc): - const rootsThreshold = 10 # broken with -d:nimStressOrc: 10 and for havlak iterations 1..8 -else: - var rootsThreshold = defaultThreshold +when defined(nimOrcStats): + var freedCyclicObjects {.threadvar.}: int proc partialCollect(lowMark: int) = when false: @@ -365,6 +385,8 @@ proc partialCollect(lowMark: int) = roots.len - lowMark) roots.len = lowMark deinit j.traceStack + when defined(nimOrcStats): + inc freedCyclicObjects, j.freed proc collectCycles() = ## Collect cycles. @@ -385,33 +407,44 @@ proc collectCycles() = collectCyclesBacon(j, 0) deinit j.traceStack - deinit roots + if roots.len == 0: + deinit roots when not defined(nimStressOrc): # compute the threshold based on the previous history # of the cycle collector's effectiveness: # we're effective when we collected 50% or more of the nodes # we touched. If we're effective, we can reset the threshold: - if j.keepThreshold and rootsThreshold <= defaultThreshold: + if j.keepThreshold: discard elif j.freed * 2 >= j.touched: when not defined(nimFixedOrc): rootsThreshold = max(rootsThreshold div 3 * 2, 16) else: - rootsThreshold = defaultThreshold + rootsThreshold = 0 #cfprintf(cstderr, "[collectCycles] freed %ld, touched %ld new threshold %ld\n", j.freed, j.touched, rootsThreshold) elif rootsThreshold < high(int) div 4: - rootsThreshold = rootsThreshold * 3 div 2 + rootsThreshold = (if rootsThreshold <= 0: defaultThreshold else: rootsThreshold) * 3 div 2 when logOrc: cfprintf(cstderr, "[collectCycles] end; freed %ld new threshold %ld touched: %ld mem: %ld rcSum: %ld edges: %ld\n", j.freed, rootsThreshold, j.touched, getOccupiedMem(), j.rcSum, j.edges) + when defined(nimOrcStats): + inc freedCyclicObjects, j.freed + +when defined(nimOrcStats): + type + OrcStats* = object ## Statistics of the cycle collector subsystem. + freedCyclicObjects*: int ## Number of freed cyclic objects. + proc GC_orcStats*(): OrcStats = + ## Returns the statistics of the cycle collector subsystem. + result = OrcStats(freedCyclicObjects: freedCyclicObjects) proc registerCycle(s: Cell; desc: PNimTypeV2) = s.rootIdx = roots.len+1 if roots.d == nil: init(roots) add(roots, s, desc) - if roots.len >= rootsThreshold: + if roots.len - defaultThreshold >= rootsThreshold: collectCycles() when logOrc: writeCell("[added root]", s, desc) @@ -424,13 +457,13 @@ proc GC_runOrc* = orcAssert roots.len == 0, "roots not empty!" proc GC_enableOrc*() = - ## Enables the cycle collector subsystem of `--gc:orc`. This is a `--gc:orc` + ## Enables the cycle collector subsystem of `--mm:orc`. This is a `--mm:orc` ## specific API. Check with `when defined(gcOrc)` for its existence. when not defined(nimStressOrc): - rootsThreshold = defaultThreshold + rootsThreshold = 0 proc GC_disableOrc*() = - ## Disables the cycle collector subsystem of `--gc:orc`. This is a `--gc:orc` + ## Disables the cycle collector subsystem of `--mm:orc`. This is a `--mm:orc` ## specific API. Check with `when defined(gcOrc)` for its existence. when not defined(nimStressOrc): rootsThreshold = high(int) @@ -441,16 +474,16 @@ proc GC_partialCollect*(limit: int) = partialCollect(limit) proc GC_fullCollect* = - ## Forces a full garbage collection pass. With `--gc:orc` triggers the cycle + ## Forces a full garbage collection pass. With `--mm:orc` triggers the cycle ## collector. This is an alias for `GC_runOrc`. collectCycles() proc GC_enableMarkAndSweep*() = - ## For `--gc:orc` an alias for `GC_enableOrc`. + ## For `--mm:orc` an alias for `GC_enableOrc`. GC_enableOrc() proc GC_disableMarkAndSweep*() = - ## For `--gc:orc` an alias for `GC_disableOrc`. + ## For `--mm:orc` an alias for `GC_disableOrc`. GC_disableOrc() const @@ -485,6 +518,19 @@ proc nimDecRefIsLastCyclicDyn(p: pointer): bool {.compilerRtl, inl.} = #if cell.color == colPurple: rememberCycle(result, cell, cast[ptr PNimTypeV2](p)[]) +proc nimDecRefIsLastDyn(p: pointer): bool {.compilerRtl, inl.} = + if p != nil: + var cell = head(p) + if (cell.rc and not rcMask) == 0: + result = true + #cprintf("[DESTROY] %p\n", p) + else: + dec cell.rc, rcIncrement + #if cell.color == colPurple: + if result: + if cell.rootIdx > 0: + unregisterCycle(cell) + proc nimDecRefIsLastCyclicStatic(p: pointer; desc: PNimTypeV2): bool {.compilerRtl, inl.} = if p != nil: var cell = head(p) |