new GC state to sweep 'localgc' list + small changes in sweep control

lgc.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 2.155 2013/08/28 18:30:26 roberto Exp roberto $
+** $Id: lgc.c,v 2.156 2013/08/29 13:34:16 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -979,12 +979,9 @@ static void setpause (global_State *g, l_mem estimate) {
 }
 
 
-#define sweepphases	(bitmask(GCSsweepudata) | bitmask(GCSsweep))
-
-
 /*
-** enter first sweep phase and prepare pointers for other sweep phases.
-** The calls to 'sweeptolive' make pointers point to an object inside
+** Enter first sweep phase.
+** The call to 'sweeptolive' makes pointer point to an object inside
 ** the list (instead of to the header), so that the real sweep do not
 ** need to skip objects created between "now" and the start of the real
 ** sweep.
@@ -993,11 +990,9 @@ static void setpause (global_State *g, l_mem estimate) {
 static int entersweep (lua_State *L) {
   global_State *g = G(L);
   int n = 0;
-  g->gcstate = GCSsweepudata;
-  lua_assert(g->sweepgc == NULL && g->sweepfin == NULL);
-  /* prepare to sweep finalizable objects and regular objects */
-  g->sweepfin = sweeptolive(L, &g->finobj, &n);
-  g->sweepgc = sweeptolive(L, &g->allgc, &n);
+  g->gcstate = GCSsweeplocal;
+  lua_assert(g->sweepgc == NULL);
+  g->sweepgc = sweeptolive(L, &g->localgc, &n);
   return n;
 }
 
@@ -1068,6 +1063,20 @@ static l_mem atomic (lua_State *L) {
 }
 
 
+static lu_mem sweepstep (lua_State *L, global_State *g,
+                         int nextstate, GCObject **nextlist) {
+  if (g->sweepgc) {  /* is there still something to sweep? */
+    g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
+    return (GCSWEEPMAX * GCSWEEPCOST);
+  }
+  else {  /* next phase */
+    g->gcstate = nextstate;
+    g->sweepgc = nextlist;
+    return 0;
+  }
+}
+
+
 static lu_mem singlestep (lua_State *L) {
   global_State *g = G(L);
   switch (g->gcstate) {
@@ -1096,30 +1105,21 @@ static lu_mem singlestep (lua_State *L) {
       sw = entersweep(L);
       return work + sw * GCSWEEPCOST;
     }
-    case GCSsweepudata: {
-      if (g->sweepfin) {
-        g->sweepfin = sweeplist(L, g->sweepfin, GCSWEEPMAX);
-        return GCSWEEPMAX*GCSWEEPCOST;
-      }
-      else {
-        sweepwholelist(L, &g->localgc);
-        g->gcstate = GCSsweep;
-        return GCLOCALPAUSE / 4;  /* some magic for now */
-      }
+    case GCSsweeplocal: {
+      return sweepstep(L, g, GCSsweepfin, &g->finobj);
     }
-    case GCSsweep: {
-      if (g->sweepgc) {
-        g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
-        return GCSWEEPMAX*GCSWEEPCOST;
-      }
-      else {
-        /* sweep main thread */
-        GCObject *mt = obj2gco(g->mainthread);
-        sweeplist(L, &mt, 1);
-        checkBuffer(L);
-        g->gcstate = GCSpause;  /* finish collection */
-        return GCSWEEPCOST;
-      }
+    case GCSsweepfin: {
+      return sweepstep(L, g, GCSsweepall, &g->allgc);
+    }
+    case GCSsweepall: {
+      return sweepstep(L, g, GCSsweepmainth, NULL);
+    }
+    case GCSsweepmainth: {  /* sweep main thread */
+      GCObject *mt = obj2gco(g->mainthread);
+      sweeplist(L, &mt, 1);
+      checkBuffer(L);
+      g->gcstate = GCSpause;  /* finish collection */
+      return GCSWEEPCOST;
     }
     default: lua_assert(0); return 0;
   }

lgc.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.h,v 2.68 2013/08/27 20:04:00 roberto Exp roberto $
+** $Id: lgc.h,v 2.69 2013/08/29 13:49:57 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -38,13 +38,15 @@
 */
 #define GCSpropagate	0
 #define GCSatomic	1
-#define GCSsweepudata	2
-#define GCSsweep	3
-#define GCSpause	4
+#define GCSsweeplocal	2
+#define GCSsweepfin	3
+#define GCSsweepall	4
+#define GCSsweepmainth	5
+#define GCSpause	6
 
 
 #define issweepphase(g)  \
-	(GCSsweepudata <= (g)->gcstate && (g)->gcstate <= GCSsweep)
+	(GCSsweeplocal <= (g)->gcstate && (g)->gcstate <= GCSsweepmainth)
 
 
 /*

lstate.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.c,v 2.107 2013/08/27 18:53:35 roberto Exp roberto $
+** $Id: lstate.c,v 2.108 2013/08/28 18:30:26 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -301,7 +301,7 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
   g->finobj = NULL;
   g->tobefnz = NULL;
   g->fixedgc = NULL;
-  g->sweepgc = g->sweepfin = NULL;
+  g->sweepgc = NULL;
   g->gray = g->grayagain = NULL;
   g->weak = g->ephemeron = g->allweak = NULL;
   g->totalbytes = sizeof(LG);

lstate.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.h,v 2.90 2013/08/26 12:41:10 roberto Exp roberto $
+** $Id: lstate.h,v 2.91 2013/08/27 18:53:35 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -122,8 +122,7 @@ typedef struct global_State {
   GCObject *allgc;  /* list of all collectable objects */
   GCObject *localgc;  /* list of local objects */
   GCObject *finobj;  /* list of collectable objects with finalizers */
-  GCObject **sweepgc;  /* current position of sweep in list 'allgc' */
-  GCObject **sweepfin;  /* current position of sweep in list 'finobj' */
+  GCObject **sweepgc;  /* current position of sweep in list */
   GCObject *gray;  /* list of gray objects */
   GCObject *grayagain;  /* list of objects to be traversed atomically */
   GCObject *weak;  /* list of tables with weak values */

ltests.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.c,v 2.150 2013/08/27 18:53:35 roberto Exp roberto $
+** $Id: ltests.c,v 2.151 2013/08/27 20:04:00 roberto Exp roberto $
 ** Internal Module for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
@@ -653,7 +653,8 @@ static int gc_local (lua_State *L) {
 
 static int gc_state (lua_State *L) {
   static const char *statenames[] = {"propagate", "atomic",
-    "sweepudata", "sweep", "pause", ""};
+    "sweeplocal", "sweepfin", "sweepall", "sweepmainth",
+    "pause", ""};
   int option = luaL_checkoption(L, 1, "", statenames);
   if (option == GCSpause + 1) {
     lua_pushstring(L, statenames[G(L)->gcstate]);