commit 7444b5a1d5f66e8af031b575ec1c264e6937980d
parent e7ce7e1850551e40f7a86713c9068f9d4e414d00
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 5 May 2010 10:39:34 -0300
better documentation of GC costs
Diffstat:
M | lgc.c | | | 38 | ++++++++++++++++++++++++++------------ |
1 file changed, 26 insertions(+), 12 deletions(-)
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.86 2010/05/03 17:39:48 roberto Exp roberto $
+** $Id: lgc.c,v 2.87 2010/05/04 18:09:06 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -24,13 +24,28 @@
+/* how much to allocate before next GC step */
#define GCSTEPSIZE 1024
+
+/* maximum numer of elements to sweep in each single step */
#define GCSWEEPMAX 40
+
+/* cost of sweeping one element */
#define GCSWEEPCOST 1
+
+/* maximum number of finalizers to call in each GC step */
#define GCFINALIZENUM 4
+
+/* cost of marking the root set */
#define GCROOTCOST 10
+
+/* cost of atomic step */
#define GCATOMICCOST 1000
+/* basic cost to traverse one object (to be added to the links the
+ object may have) */
+#define TRAVCOST 5
+
/*
** standard negative debt for GC; a reasonable "time" to wait before
@@ -317,7 +332,7 @@ static void traverseweakvalue (global_State *g, Table *h) {
markvalue(g, gkey(n)); /* mark key */
}
}
- linktable(h, &g->weak); /* go to appropriate list */
+ linktable(h, &g->weak); /* link into appropriate list */
}
@@ -383,20 +398,20 @@ static int traversetable (global_State *g, Table *h) {
black2gray(obj2gco(h)); /* keep table gray */
if (!weakkey) { /* strong keys? */
traverseweakvalue(g, h);
- return 1 + sizenode(h);
+ return TRAVCOST + sizenode(h);
}
else if (!weakvalue) { /* strong values? */
traverseephemeron(g, h);
- return 1 + h->sizearray + sizenode(h);
+ return TRAVCOST + h->sizearray + sizenode(h);
}
else {
linktable(h, &g->allweak); /* nothing to traverse now */
- return 1;
+ return TRAVCOST;
}
} /* else go through */
}
traversestrongtable(g, h);
- return 1 + h->sizearray + (2 * sizenode(h));
+ return TRAVCOST + h->sizearray + (2 * sizenode(h));
}
@@ -411,7 +426,7 @@ static int traverseproto (global_State *g, Proto *f) {
markobject(g, f->p[i]);
for (i = 0; i < f->sizelocvars; i++) /* mark local-variable names */
stringmark(f->locvars[i].varname);
- return 1 + f->sizek + f->sizeupvalues + f->sizep + f->sizelocvars;
+ return TRAVCOST + f->sizek + f->sizeupvalues + f->sizep + f->sizelocvars;
}
@@ -420,7 +435,6 @@ static l_mem traverseclosure (global_State *g, Closure *cl) {
int i;
for (i=0; i<cl->c.nupvalues; i++) /* mark its upvalues */
markvalue(g, &cl->c.upvalue[i]);
- return sizeCclosure(cl->c.nupvalues);
}
else {
int i;
@@ -428,14 +442,14 @@ static l_mem traverseclosure (global_State *g, Closure *cl) {
markobject(g, cl->l.p); /* mark its prototype */
for (i=0; i<cl->l.nupvalues; i++) /* mark its upvalues */
markobject(g, cl->l.upvals[i]);
- return sizeLclosure(cl->l.nupvalues);
}
+ return TRAVCOST + cl->c.nupvalues;
}
static int traversestack (global_State *g, lua_State *L) {
StkId o = L->stack;
- if (L->stack == NULL)
+ if (o == NULL)
return 1; /* stack not completely built yet */
for (; o < L->top; o++)
markvalue(g, o);
@@ -444,7 +458,7 @@ static int traversestack (global_State *g, lua_State *L) {
for (; o < lim; o++) /* clear not-marked stack slice */
setnilvalue(o);
}
- return 1 + cast_int(o - L->stack);
+ return TRAVCOST + cast_int(o - L->stack);
}
@@ -803,7 +817,7 @@ static void atomic (lua_State *L) {
cleartable(g->weak);
cleartable(g->ephemeron);
cleartable(g->allweak);
- /*lua_checkmemory(L);*/
+ lua_checkmemory(L);
g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */
}