diff --git a/mps/code/amsss.c b/mps/code/amsss.c
index 1d04f199349..8538fd354e2 100644
--- a/mps/code/amsss.c
+++ b/mps/code/amsss.c
@@ -27,7 +27,7 @@
 #define totalSizeSTEP   200 * (size_t)1024
 /* objNULL needs to be odd so that it's ignored in exactRoots. */
 #define objNULL         ((mps_addr_t)MPS_WORD_CONST(0xDECEA5ED))
-#define testArenaSIZE   ((size_t)16<<20)
+#define testArenaSIZE   ((size_t)1<<20)
 #define initTestFREQ    3000
 #define splatTestFREQ   6000
 static mps_gen_param_s testChain[1] = { { 160, 0.90 } };
@@ -107,7 +107,8 @@ static mps_addr_t make(void)
 static mps_pool_debug_option_s freecheckOptions =
   { NULL, 0, (const void *)"Dead", 4 };
 
-static void *test(void *arg, size_t haveAmbigous)
+static void test_pool(mps_class_t pool_class, mps_arg_s args[],
+                      size_t haveAmbiguous)
 {
   mps_pool_t pool;
   mps_root_t exactRoot, ambigRoot = NULL;
@@ -116,14 +117,13 @@ static void *test(void *arg, size_t haveAmbigous)
   mps_ap_t busy_ap;
   mps_addr_t busy_init;
 
-  pool = (mps_pool_t)arg;
-
+  die(mps_pool_create_k(&pool, arena, pool_class, args), "pool_create");
   die(mps_ap_create(&ap, pool, mps_rank_exact()), "BufferCreate");
   die(mps_ap_create(&busy_ap, pool, mps_rank_exact()), "BufferCreate 2");
 
   for(i = 0; i < exactRootsCOUNT; ++i)
     exactRoots[i] = objNULL;
-  if (haveAmbigous)
+  if (haveAmbiguous)
     for(i = 0; i < ambigRootsCOUNT; ++i)
       ambigRoots[i] = rnd_addr();
 
@@ -132,7 +132,7 @@ static void *test(void *arg, size_t haveAmbigous)
                                    &exactRoots[0], exactRootsCOUNT,
                                    (mps_word_t)1),
       "root_create_table(exact)");
-  if (haveAmbigous)
+  if (haveAmbiguous)
     die(mps_root_create_table(&ambigRoot, arena,
                               mps_rank_ambig(), (mps_rm_t)0,
                               &ambigRoots[0], ambigRootsCOUNT),
@@ -154,7 +154,7 @@ static void *test(void *arg, size_t haveAmbigous)
     }
 
     r = (size_t)rnd();
-    if (!haveAmbigous || (r & 1)) {
+    if (!haveAmbiguous || (r & 1)) {
       i = (r >> 1) % exactRootsCOUNT;
       if (exactRoots[i] != objNULL)
         cdie(dylan_check(exactRoots[i]), "dying root check");
@@ -187,80 +187,49 @@ static void *test(void *arg, size_t haveAmbigous)
   mps_ap_destroy(busy_ap);
   mps_ap_destroy(ap);
   mps_root_destroy(exactRoot);
-  if (haveAmbigous)
+  if (haveAmbiguous)
     mps_root_destroy(ambigRoot);
 
-  return NULL;
+  mps_pool_destroy(pool);
 }
 
 
 int main(int argc, char *argv[])
 {
+  int i;
   mps_thr_t thread;
   mps_fmt_t format;
   mps_chain_t chain;
-  mps_pool_t pool;
-  void *r;
 
   testlib_init(argc, argv);
 
   die(mps_arena_create(&arena, mps_arena_class_vm(), testArenaSIZE),
       "arena_create");
+  die(mps_arena_commit_limit_set(arena, 2 * testArenaSIZE), "commit_limit_set");
+
   mps_message_type_enable(arena, mps_message_type_gc_start());
   mps_message_type_enable(arena, mps_message_type_gc());
   die(mps_thread_reg(&thread, arena), "thread_reg");
   die(mps_fmt_create_A(&format, arena, dylan_fmt_A()), "fmt_create");
   die(mps_chain_create(&chain, arena, 1, testChain), "chain_create");
 
-  /* TODO: Add tests using the arena default chain. */
-
-  printf("\n\n****************************** Testing AMS Debug\n");
-  MPS_ARGS_BEGIN(args) {
-    MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
-    MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
-    MPS_ARGS_ADD(args, MPS_KEY_AMS_SUPPORT_AMBIGUOUS, FALSE);
-    MPS_ARGS_ADD(args, MPS_KEY_POOL_DEBUG_OPTIONS, &freecheckOptions);
-    die(mps_pool_create_k(&pool, arena, mps_class_ams_debug(), args),
-        "pool_create(ams_debug,share)");
-  } MPS_ARGS_END(args);
-  mps_tramp(&r, test, pool, 0);
-  mps_pool_destroy(pool);
-
-  printf("\n\n****************************** Testing AMS Debug\n");
-  MPS_ARGS_BEGIN(args) {
-    MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
-    MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
-    MPS_ARGS_ADD(args, MPS_KEY_AMS_SUPPORT_AMBIGUOUS, TRUE);
-    MPS_ARGS_ADD(args, MPS_KEY_POOL_DEBUG_OPTIONS, &freecheckOptions);
-    die(mps_pool_create_k(&pool, arena, mps_class_ams_debug(), args),
-        "pool_create(ams_debug,ambig)");
-  } MPS_ARGS_END(args);
-  mps_tramp(&r, test, pool, 1);
-  mps_pool_destroy(pool);
-
-  printf("\n\n****************************** Testing AMS\n");
-  MPS_ARGS_BEGIN(args) {
-    MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
-    MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
-    MPS_ARGS_ADD(args, MPS_KEY_AMS_SUPPORT_AMBIGUOUS, TRUE);
-    MPS_ARGS_ADD(args, MPS_KEY_POOL_DEBUG_OPTIONS, &freecheckOptions);
-    die(mps_pool_create_k(&pool, arena, mps_class_ams(), args),
-        "pool_create(ams,ambig)");
-  } MPS_ARGS_END(args);
-  mps_tramp(&r, test, pool, 1);
-  mps_pool_destroy(pool);
-
-  printf("\n\n****************************** Testing AMS\n");
-  MPS_ARGS_BEGIN(args) {
-    MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
-    MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
-    MPS_ARGS_ADD(args, MPS_KEY_AMS_SUPPORT_AMBIGUOUS, FALSE);
-    MPS_ARGS_ADD(args, MPS_KEY_POOL_DEBUG_OPTIONS, &freecheckOptions);
-    die(mps_pool_create_k(&pool, arena, mps_class_ams(), args),
-        "pool_create(ams,share)");
-  } MPS_ARGS_END(args);
-  mps_tramp(&r, test, pool, 0);
-  mps_pool_destroy(pool);
+  for (i = 0; i < 8; i++) {
+    int debug = i % 2;
+    int ownChain = (i / 2) % 2;
+    int ambig = (i / 4) % 2;
+    printf("\n\n*** AMS%s with %sCHAIN and %sSUPPORT_AMBIGUOUS\n",
+           debug ? " Debug" : "",
+           ownChain ? "" : "!",
+           ambig ? "" : "!");
+    MPS_ARGS_BEGIN(args) {
+      MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
+      if (chain)
+        MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
+      MPS_ARGS_ADD(args, MPS_KEY_AMS_SUPPORT_AMBIGUOUS, ambig);
+      MPS_ARGS_ADD(args, MPS_KEY_POOL_DEBUG_OPTIONS, &freecheckOptions);
+      test_pool(debug ? mps_class_ams_debug() : mps_class_ams(), args, TRUE);
+    } MPS_ARGS_END(args);
+  }
 
   mps_chain_destroy(chain);
   mps_fmt_destroy(format);
diff --git a/mps/code/awlut.c b/mps/code/awlut.c
index c62153ed44c..464a2dba91f 100644
--- a/mps/code/awlut.c
+++ b/mps/code/awlut.c
@@ -275,9 +275,6 @@ static void *setup(void *v, size_t s)
   die(mps_fmt_create_A(&dylanweakfmt, arena, dylan_fmt_A_weak()),
       "Format Create (weak)\n");
   MPS_ARGS_BEGIN(args) {
-    /* Ask the leafpool to allocate in the nursery, as we're using it to test
-       weaknesss and want things to die in it promptly. */
-    MPS_ARGS_ADD(args, MPS_KEY_GEN, 0);
     MPS_ARGS_ADD(args, MPS_KEY_FORMAT, dylanfmt);
     die(mps_pool_create_k(&leafpool, arena, mps_class_lo(), args),
         "Leaf Pool Create\n");
diff --git a/mps/code/awluthe.c b/mps/code/awluthe.c
index d3b2d572319..6ea468977f1 100644
--- a/mps/code/awluthe.c
+++ b/mps/code/awluthe.c
@@ -277,9 +277,6 @@ static void *setup(void *v, size_t s)
   die(EnsureHeaderFormat(&dylanfmt, arena), "EnsureHeaderFormat");
   die(EnsureHeaderWeakFormat(&dylanweakfmt, arena), "EnsureHeaderWeakFormat");
   MPS_ARGS_BEGIN(args) {
-    /* Ask the leafpool to allocate in the nursery, as we're using it to test
-       weaknesss and want things to die in it promptly. */
-    MPS_ARGS_ADD(args, MPS_KEY_GEN, 0);
     MPS_ARGS_ADD(args, MPS_KEY_FORMAT, dylanfmt);
     die(mps_pool_create_k(&leafpool, arena, mps_class_lo(), args),
         "Leaf Pool Create\n");
diff --git a/mps/code/chain.h b/mps/code/chain.h
index e47f8000c0b..ec5bc228ebf 100644
--- a/mps/code/chain.h
+++ b/mps/code/chain.h
@@ -81,7 +81,6 @@ extern Bool ChainCheck(Chain chain);
 
 extern double ChainDeferral(Chain chain);
 extern Res ChainCondemnAuto(double *mortalityReturn, Chain chain, Trace trace);
-extern Res ChainCondemnAll(Chain chain, Trace trace);
 extern void ChainStartGC(Chain chain, Trace trace);
 extern void ChainEndGC(Chain chain, Trace trace);
 extern size_t ChainGens(Chain chain);
diff --git a/mps/code/finaltest.c b/mps/code/finaltest.c
index 88895027286..f449d7e1acf 100644
--- a/mps/code/finaltest.c
+++ b/mps/code/finaltest.c
@@ -6,6 +6,20 @@
  *
  * DESIGN
  *
+ * .mode: This test has two modes.
+ *
+ * .mode.park: In this mode, we use the arena's default generation
+ * chain, leave the arena parked and call mps_arena_collect. This
+ * tests that the default generation chain works and that all segments
+ * get condemned via TraceStartCollectAll. (See job003771 item 4.)
+ *
+ * .mode.poll: In this mode, we use our own generation chain (with
+ * small generations), allocate into generation 1, unclamp the arena,
+ * and provoke collection by allocating. This tests that custom
+ * generation chains work, and that segments get condemned via
+ * TracePoll even if there is no allocation into generation 0 of the
+ * chain. (See job003771 item 5.)
+ *
  * DEPENDENCIES
  *
  * This test uses the dylan object format, but the reliance on this
@@ -16,6 +30,7 @@
  * This code was created by first copying <code/finalcv.c>
  */
 
+#include "mpm.h"
 #include "testlib.h"
 #include "mpslib.h"
 #include "mps.h"
@@ -30,10 +45,15 @@
 
 #include <stdio.h> /* fflush, printf, stdout */
 
+enum {
+  ModePARK,                     /* .mode.park */
+  ModePOLL                      /* .mode.poll */
+};
+
 
 #define testArenaSIZE   ((size_t)16<<20)
 #define rootCOUNT 20
-#define maxtreeDEPTH 10
+#define maxtreeDEPTH 9
 #define collectionCOUNT 10
 
 
@@ -126,17 +146,21 @@ static mps_addr_t test_awl_find_dependent(mps_addr_t addr)
 
 static void *root[rootCOUNT];
 
-static void test_trees(const char *name, mps_arena_t arena, mps_ap_t ap,
+static void test_trees(int mode, const char *name, mps_arena_t arena,
+                       mps_ap_t ap,
                        mps_word_t (*make)(mps_word_t, mps_ap_t),
                        void (*reg)(mps_word_t, mps_arena_t))
 {
   size_t collections = 0;
   size_t finals = 0;
   size_t i;
+  int object_alloc;
 
   object_count = 0;
 
   printf("Making some %s finalized trees of objects.\n", name);
+  mps_arena_park(arena);
+
   /* make some trees */
   for(i = 0; i < rootCOUNT; ++i) {
     root[i] = (void *)(*make)(maxtreeDEPTH, ap);
@@ -151,10 +175,23 @@ static void test_trees(const char *name, mps_arena_t arena, mps_ap_t ap,
 
   while (finals < object_count && collections < collectionCOUNT) {
     mps_word_t final_this_time = 0;
-    printf("Collecting...");
-    (void)fflush(stdout);
-    die(mps_arena_collect(arena), "collect");
-    printf(" Done.\n");
+    switch (mode) {
+    default:
+    case ModePARK:
+      printf("Collecting...");
+      (void)fflush(stdout);
+      die(mps_arena_collect(arena), "collect");
+      printf(" Done.\n");
+      break;
+    case ModePOLL:
+      mps_arena_release(arena);
+      printf("Allocating...");
+      (void)fflush(stdout);
+      object_alloc = 0;
+      while (object_alloc < 1000 && !mps_message_poll(arena))
+        (void)DYLAN_INT(object_alloc++);
+      break;
+    }
     ++ collections;
     while (mps_message_poll(arena)) {
       mps_message_t message;
@@ -170,10 +207,14 @@ static void test_trees(const char *name, mps_arena_t arena, mps_ap_t ap,
            " of %"PRIuLONGEST"\n", (ulongest_t)final_this_time,
            (ulongest_t)finals, (ulongest_t)object_count);
   }
-  cdie(finals == object_count, "Not all objects were finalized.");
+  if (finals != object_count)
+    error("Not all objects were finalized for %s in mode %s.",
+          BufferOfAP(ap)->pool->class->name,
+          mode == ModePOLL ? "POLL" : "PARK");
 }
 
-static void *test(mps_arena_t arena, mps_class_t pool_class)
+static void test_pool(int mode, mps_arena_t arena, mps_chain_t chain,
+                      mps_class_t pool_class)
 {
   mps_ap_t ap;
   mps_fmt_t fmt;
@@ -182,10 +223,13 @@ static void *test(mps_arena_t arena, mps_class_t pool_class)
 
   die(mps_fmt_create_A(&fmt, arena, dylan_fmt_A()), "fmt_create\n");
   MPS_ARGS_BEGIN(args) {
-    /* Allocate into generation 0 so that they get finalized quickly. */
-    MPS_ARGS_ADD(args, MPS_KEY_GEN, 0);
     MPS_ARGS_ADD(args, MPS_KEY_FORMAT, fmt);
-    MPS_ARGS_ADD(args, MPS_KEY_AWL_FIND_DEPENDENT, test_awl_find_dependent);
+    if (mode == ModePOLL) {
+      MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
+      MPS_ARGS_ADD(args, MPS_KEY_GEN, 1);
+    }
+    if (pool_class == mps_class_awl())
+      MPS_ARGS_ADD(args, MPS_KEY_AWL_FIND_DEPENDENT, test_awl_find_dependent);
     die(mps_pool_create_k(&pool, arena, pool_class, args),
         "pool_create\n");
   } MPS_ARGS_END(args);
@@ -194,19 +238,25 @@ static void *test(mps_arena_t arena, mps_class_t pool_class)
       "root_create\n");
   die(mps_ap_create(&ap, pool, mps_rank_exact()), "ap_create\n");
 
-  mps_message_type_enable(arena, mps_message_type_finalization());
-
-  mps_arena_park(arena);
-
-  test_trees("numbered", arena, ap, make_numbered_tree, register_numbered_tree);
-  test_trees("indirect", arena, ap, make_indirect_tree, register_indirect_tree);
+  test_trees(mode, "numbered", arena, ap, make_numbered_tree,
+             register_numbered_tree);
+  test_trees(mode, "indirect", arena, ap, make_indirect_tree,
+             register_indirect_tree);
 
   mps_ap_destroy(ap);
   mps_root_destroy(mps_root);
   mps_pool_destroy(pool);
   mps_fmt_destroy(fmt);
+}
 
-  return NULL;
+
+static void test_mode(int mode, mps_arena_t arena, mps_chain_t chain)
+{
+  test_pool(mode, arena, chain, mps_class_amc());
+  test_pool(mode, arena, chain, mps_class_amcz());
+  test_pool(mode, arena, chain, mps_class_ams());
+  /* test_pool(mode, arena, chain, mps_class_lo()); TODO: job003773 */
+  /* test_pool(mode, arena, chain, mps_class_awl()); TODO: job003772 */
 }
 
 
@@ -214,19 +264,27 @@ int main(int argc, char *argv[])
 {
   mps_arena_t arena;
   mps_thr_t thread;
+  mps_chain_t chain;
+  mps_gen_param_s params[2];
+  size_t gens = 2;
+  size_t i;
 
   testlib_init(argc, argv);
 
   die(mps_arena_create(&arena, mps_arena_class_vm(), testArenaSIZE),
       "arena_create\n");
+  mps_message_type_enable(arena, mps_message_type_finalization());
   die(mps_thread_reg(&thread, arena), "thread_reg\n");
+  for (i = 0; i < gens; ++i) {
+    params[i].mps_capacity = 1;
+    params[i].mps_mortality = 0.5;
+  }
+  die(mps_chain_create(&chain, arena, gens, params), "chain_create\n");
 
-  test(arena, mps_class_amc());
-  test(arena, mps_class_amcz());
-  test(arena, mps_class_ams());
-  test(arena, mps_class_awl());
-  /* TODO: test(arena, mps_class_lo()); */
+  test_mode(ModePOLL, arena, chain);
+  test_mode(ModePARK, arena, NULL);
 
+  mps_chain_destroy(chain);
   mps_thread_dereg(thread);
   mps_arena_destroy(arena);
 
diff --git a/mps/code/locus.c b/mps/code/locus.c
index a704c8b820b..6e6e22128b7 100644
--- a/mps/code/locus.c
+++ b/mps/code/locus.c
@@ -287,13 +287,21 @@ Res ChainAlloc(Seg *segReturn, Chain chain, Serial genNr, SegClass class,
 
 double ChainDeferral(Chain chain)
 {
+  double time = DBL_MAX;
+  size_t i;
+
   AVERT(Chain, chain);
 
-  if (chain->activeTraces != TraceSetEMPTY)
-    return DBL_MAX;
-  else
-    return chain->gens[0].capacity * 1024.0
-           - (double)GenDescNewSize(&chain->gens[0]);
+  if (chain->activeTraces == TraceSetEMPTY) {
+    for (i = 0; i < chain->genCount; ++i) {
+      double genTime = chain->gens[i].capacity * 1024.0
+        - (double)GenDescNewSize(&chain->gens[i]);
+      if (genTime < time)
+        time = genTime;
+    }
+  }
+
+  return time;
 }
 
 
@@ -306,7 +314,7 @@ double ChainDeferral(Chain chain)
 Res ChainCondemnAuto(double *mortalityReturn, Chain chain, Trace trace)
 {
   Res res;
-  Serial topCondemnedGenSerial, currGenSerial;
+  size_t topCondemnedGen, i;
   GenDesc gen;
   ZoneSet condemnedSet = ZoneSetEMPTY;
   Size condemnedSize = 0, survivorSize = 0, genNewSize, genTotalSize;
@@ -314,33 +322,39 @@ Res ChainCondemnAuto(double *mortalityReturn, Chain chain, Trace trace)
   AVERT(Chain, chain);
   AVERT(Trace, trace);
 
-  /* Find lowest gen within its capacity, set topCondemnedGenSerial to the */
-  /* preceeding one. */
-  currGenSerial = 0;
-  gen = &chain->gens[0];
-  AVERT(GenDesc, gen);
-  genNewSize = GenDescNewSize(gen);
-  do { /* At this point, we've decided to collect currGenSerial. */
-    topCondemnedGenSerial = currGenSerial;
+  /* Find the highest generation that's over capacity. We will condemn
+   * this and all lower generations in the chain. */
+  topCondemnedGen = chain->genCount;
+  for (;;) {
+    /* It's an error to call this function unless some generation is
+     * over capacity as reported by ChainDeferral. */
+    AVER(topCondemnedGen > 0);
+    if (topCondemnedGen == 0)
+      return ResFAIL;
+    -- topCondemnedGen;
+    gen = &chain->gens[topCondemnedGen];
+    AVERT(GenDesc, gen);
+    genNewSize = GenDescNewSize(gen);
+    if (genNewSize >= gen->capacity * (Size)1024)
+      break;
+  }
+
+  /* At this point, we've decided to condemn topCondemnedGen and all
+   * lower generations. */
+  for (i = 0; i <= topCondemnedGen; ++i) {
+    gen = &chain->gens[i];
+    AVERT(GenDesc, gen);
     condemnedSet = ZoneSetUnion(condemnedSet, gen->zones);
     genTotalSize = GenDescTotalSize(gen);
+    genNewSize = GenDescNewSize(gen);
     condemnedSize += genTotalSize;
     survivorSize += (Size)(genNewSize * (1.0 - gen->mortality))
                     /* predict survivors will survive again */
                     + (genTotalSize - genNewSize);
-
-    /* is there another one to consider? */
-    currGenSerial += 1;
-    if (currGenSerial >= chain->genCount)
-      break; /* reached the top */
-    gen = &chain->gens[currGenSerial];
-    AVERT(GenDesc, gen);
-    genNewSize = GenDescNewSize(gen);
-  } while (genNewSize >= gen->capacity * (Size)1024);
+  }
   
   AVER(condemnedSet != ZoneSetEMPTY || condemnedSize == 0);
-  EVENT3(ChainCondemnAuto, chain, topCondemnedGenSerial, chain->genCount);
-  UNUSED(topCondemnedGenSerial); /* only used for EVENT */
+  EVENT3(ChainCondemnAuto, chain, topCondemnedGen, chain->genCount);
   
   /* Condemn everything in these zones. */
   if (condemnedSet != ZoneSetEMPTY) {
@@ -354,41 +368,6 @@ Res ChainCondemnAuto(double *mortalityReturn, Chain chain, Trace trace)
 }
 
 
-/* ChainCondemnAll -- condemn everything in the chain */
-
-Res ChainCondemnAll(Chain chain, Trace trace)
-{
-  Ring node, nextNode;
-  Bool haveWhiteSegs = FALSE;
-  Res res;
-
-  /* Condemn every segment in every pool using this chain. */
-  /* Finds the pools by iterating over the PoolGens in gen 0. */
-  RING_FOR(node, &chain->gens[0].locusRing, nextNode) {
-    PoolGen nursery = RING_ELT(PoolGen, genRing, node);
-    Pool pool = nursery->pool;
-    Ring segNode, nextSegNode;
-
-    AVERT(Pool, pool);
-    AVER(PoolHasAttr(pool, AttrGC));
-    RING_FOR(segNode, PoolSegRing(pool), nextSegNode) {
-      Seg seg = SegOfPoolRing(segNode);
-
-      res = TraceAddWhite(trace, seg);
-      if (res != ResOK)
-        goto failBegin;
-      haveWhiteSegs = TRUE;
-    }
-  }
- 
-  return ResOK;
-
-failBegin:
-  AVER(!haveWhiteSegs); /* Would leave white sets inconsistent. */
-  return res;
-}
-
-
 /* ChainStartGC -- called to notify start of GC for this chain */
 
 void ChainStartGC(Chain chain, Trace trace)
@@ -416,9 +395,11 @@ void ChainEndGC(Chain chain, Trace trace)
 Res PoolGenInit(PoolGen gen, Chain chain, Serial nr, Pool pool)
 {
   /* Can't check gen, because it's not been initialized. */
+  AVER(gen != NULL);
   AVERT(Chain, chain);
   AVER(nr <= chain->genCount);
   AVERT(Pool, pool);
+  AVER(PoolHasAttr(pool, AttrGC));
 
   gen->nr = nr;
   gen->pool = pool;
diff --git a/mps/code/trace.c b/mps/code/trace.c
index 61e9d396155..f94d245fbf7 100644
--- a/mps/code/trace.c
+++ b/mps/code/trace.c
@@ -390,6 +390,7 @@ Res TraceCondemnZones(Trace trace, ZoneSet condemnedSet)
   Seg seg;
   Arena arena;
   Res res;
+  Bool haveWhiteSegs = FALSE;
 
   AVERT(Trace, trace);
   AVER(condemnedSet != ZoneSetEMPTY);
@@ -415,7 +416,8 @@ Res TraceCondemnZones(Trace trace, ZoneSet condemnedSet)
       {
         res = TraceAddWhite(trace, seg);
         if(res != ResOK)
-          return res;
+          goto failBegin;
+        haveWhiteSegs = TRUE;
       }
     } while (SegNext(&seg, arena, seg));
   }
@@ -426,6 +428,10 @@ Res TraceCondemnZones(Trace trace, ZoneSet condemnedSet)
   AVER(ZoneSetSuper(condemnedSet, trace->white));
 
   return ResOK;
+
+failBegin:
+  AVER(!haveWhiteSegs); /* See .whiten.fail. */
+  return res;
 }
 
 
@@ -1503,21 +1509,31 @@ static Res traceCondemnAll(Trace trace)
 {
   Res res;
   Arena arena;
-  Ring chainNode, nextChainNode;
+  Ring poolNode, nextPoolNode, chainNode, nextChainNode;
   Bool haveWhiteSegs = FALSE;
 
   arena = trace->arena;
   AVERT(Arena, arena);
-  /* Condemn all the chains. */
-  RING_FOR(chainNode, &arena->chainRing, nextChainNode) {
-    Chain chain = RING_ELT(Chain, chainRing, chainNode);
 
-    AVERT(Chain, chain);
-    res = ChainCondemnAll(chain, trace);
-    if(res != ResOK)
-      goto failBegin;
-    haveWhiteSegs = TRUE;
+  /* Condemn all segments in pools with the GC attribute. */
+  RING_FOR(poolNode, &ArenaGlobals(arena)->poolRing, nextPoolNode) {
+    Pool pool = RING_ELT(Pool, arenaRing, poolNode);
+    AVERT(Pool, pool);
+
+    if (PoolHasAttr(pool, AttrGC)) {
+      Ring segNode, nextSegNode;
+      RING_FOR(segNode, PoolSegRing(pool), nextSegNode) {
+        Seg seg = SegOfPoolRing(segNode);
+        AVERT(Seg, seg);
+
+        res = TraceAddWhite(trace, seg);
+        if (res != ResOK)
+          goto failBegin;
+        haveWhiteSegs = TRUE;
+      }
+    }
   }
+
   /* Notify all the chains. */
   RING_FOR(chainNode, &arena->chainRing, nextChainNode) {
     Chain chain = RING_ELT(Chain, chainRing, chainNode);
@@ -1527,7 +1543,14 @@ static Res traceCondemnAll(Trace trace)
   return ResOK;
 
 failBegin:
-  AVER(!haveWhiteSegs); /* Would leave white sets inconsistent. */
+  /* .whiten.fail: If we successfully whitened one or more segments,
+   * but failed to whiten them all, then the white sets would now be
+   * inconsistent. This can't happen in practice (at time of writing)
+   * because all PoolWhiten methods always succeed. If we ever have a
+   * pool class that fails to whiten a segment, then this assertion
+   * will be triggered. In that case, we'll have to recover here by
+   * blackening the segments again. */
+  AVER(!haveWhiteSegs);
   return res;
 }