From 0540074ccb20249e19ddd5ff4b87b870f81e212d Mon Sep 17 00:00:00 2001
From: Richard Kistruck <rhsk@ravenbrook.com>
Date: Wed, 24 Feb 2010 16:14:38 +0000
Subject: [PATCH] mps br/padding (back out non-working changelist 169853
 (attempt to clear up what "clamped" means))

Copied from Perforce
 Change: 169854
 ServerID: perforce.ravenbrook.com
---
 mps/code/global.c | 12 +++++++++---
 mps/code/trace.c  |  4 +---
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/mps/code/global.c b/mps/code/global.c
index 346ff7bc291..2e353f9b29c 100644
--- a/mps/code/global.c
+++ b/mps/code/global.c
@@ -657,6 +657,8 @@ void ArenaPoll(Globals globals)
 
   AVERT(Globals, globals);
 
+  if (globals->clamped)
+    return;
   if (globals->insidePoll)
     return;
   if(globals->fillMutatorSize < globals->pollThreshold)
@@ -713,9 +715,8 @@ static Bool arenaShouldCollectWorld(Arena arena,
 
   /* don't collect the world if we're not given any time */
   if ((interval > 0.0) && (multiplier > 0.0)) {
-    /* don't collect the world if we're clamped or busy. */
-    if (!ArenaGlobals(arena)->clamped
-        && arena->busyTraces == TraceSetEMPTY) {
+    /* don't collect the world if we're already collecting. */
+    if (arena->busyTraces == TraceSetEMPTY) {
       /* don't collect the world if it's very small */
       arenaSize = ArenaCommitted(arena) - ArenaSpareCommitted(arena);
       if (arenaSize > 1000000) {
@@ -745,6 +746,7 @@ static Bool arenaShouldCollectWorld(Arena arena,
 
 Bool ArenaStep(Globals globals, double interval, double multiplier)
 {
+  double size;
   Size scanned;
   Bool stepped;
   Clock start, end, now;
@@ -786,6 +788,10 @@ Bool ArenaStep(Globals globals, double interval, double multiplier)
     arena->tracedTime += (now - start) / (double) clocks_per_sec;
   }
 
+  size = globals->fillMutatorSize;
+  globals->pollThreshold = size + ArenaPollALLOCTIME;
+  AVER(globals->pollThreshold > size); /* enough precision? */
+
   return stepped;
 }
 
diff --git a/mps/code/trace.c b/mps/code/trace.c
index 0186083a1c5..ff13b6180a9 100644
--- a/mps/code/trace.c
+++ b/mps/code/trace.c
@@ -531,8 +531,6 @@ static void traceFlip(Trace trace)
   AVER(trace->state == TraceUNFLIPPED);
   AVER(!TraceSetIsMember(arena->flippedTraces, trace));
 
-  AVER(ArenaGlobals(arena)->clamped == FALSE);  /* clamped => no flip */
-
   EVENT_PP(TraceFlipBegin, trace, arena);
 
   traceFlipBuffers(ArenaGlobals(arena));
@@ -1774,7 +1772,7 @@ Size TracePoll(Globals globals)
   arena = GlobalsArena(globals);
 
   scannedSize = (Size)0;
-  if(!globals->clamped && arena->busyTraces == TraceSetEMPTY) {
+  if(arena->busyTraces == TraceSetEMPTY) {
     /* If no traces are going on, see if we need to start one. */
     Size sFoundation, sCondemned, sSurvivors, sConsTrace;
     double tTracePerScan; /* tTrace/cScan */