commit a799ed5af91c642d12952586ca6ad5ad92bf7f44
parent 4082c77ff2fd09aef6131587a8e2537e86fc7d68
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 19 Oct 2012 16:00:08 -0300
more precise control for GC pause (based on threshold)
Diffstat:
M | lgc.c | | | 46 | +++++++++++++++++++++++++++------------------- |
1 file changed, 27 insertions(+), 19 deletions(-)
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.136 2012/09/11 12:53:08 roberto Exp roberto $
+** $Id: lgc.c,v 2.137 2012/10/03 12:36:17 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -43,21 +43,12 @@
*/
#define STEPMULADJ 200
+
/*
** macro to adjust 'pause': 'pause' is actually used like
** 'pause / PAUSEADJ' (value chosen by tests)
*/
-#define PAUSEADJ 200
-
-
-
-
-/*
-** standard negative debt for GC; a reasonable "time" to wait before
-** starting a new cycle
-*/
-#define stddebtest(g,e) (-cast(l_mem, (e)/PAUSEADJ) * g->gcpause)
-#define stddebt(g) stddebtest(g, gettotalbytes(g))
+#define PAUSEADJ 100
/*
@@ -908,6 +899,21 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
*/
+/*
+** set a reasonable "time" to wait before starting a new GC cycle;
+** cycle will start when memory use hits threshold
+*/
+static void setpause (global_State *g, l_mem estimate) {
+ l_mem debt, threshold;
+ estimate = estimate / PAUSEADJ; /* adjust 'estimate' */
+ threshold = (g->gcpause < MAX_LMEM / estimate) /* overflow? */
+ ? estimate * g->gcpause /* no overflow */
+ : MAX_LMEM; /* overflow; truncate to maximum */
+ debt = -cast(l_mem, threshold - gettotalbytes(g));
+ luaE_setdebt(g, debt);
+}
+
+
#define sweepphases \
(bitmask(GCSsweepstring) | bitmask(GCSsweepudata) | bitmask(GCSsweep))
@@ -1028,7 +1034,8 @@ static lu_mem singlestep (lua_State *L) {
global_State *g = G(L);
switch (g->gcstate) {
case GCSpause: {
- g->GCmemtrav = 0; /* start to count memory traversed */
+ /* start to count memory traversed */
+ g->GCmemtrav = g->strt.size * sizeof(GCObject*);
lua_assert(!isgenerational(g));
restartcollection(g);
g->gcstate = GCSpropagate;
@@ -1117,7 +1124,7 @@ static void generationalcollection (lua_State *L) {
g->GCestimate = estimate; /* keep estimate from last major coll. */
}
- luaE_setdebt(g, stddebt(g));
+ setpause(g, gettotalbytes(g));
lua_assert(g->gcstate == GCSpropagate);
}
@@ -1126,7 +1133,7 @@ static void incstep (lua_State *L) {
global_State *g = G(L);
l_mem debt = g->GCdebt;
int stepmul = g->gcstepmul;
- if (stepmul < 40) stepmul = 40; /* avoid ridiculous low values */
+ if (stepmul < 40) stepmul = 40; /* avoid ridiculous low values (and 0) */
/* convert debt from Kb to 'work units' (avoid zero debt and overflows) */
debt = (debt / STEPMULADJ) + 1;
debt = (debt < MAX_LMEM / stepmul) ? debt * stepmul : MAX_LMEM;
@@ -1135,10 +1142,11 @@ static void incstep (lua_State *L) {
debt -= work;
} while (debt > -GCSTEPSIZE && g->gcstate != GCSpause);
if (g->gcstate == GCSpause)
- debt = stddebtest(g, g->GCestimate); /* pause until next cycle */
- else
+ setpause(g, g->GCestimate); /* pause until next cycle */
+ else {
debt = (debt / stepmul) * STEPMULADJ; /* convert 'work units' to Kb */
- luaE_setdebt(g, debt);
+ luaE_setdebt(g, debt);
+ }
}
@@ -1195,7 +1203,7 @@ void luaC_fullgc (lua_State *L, int isemergency) {
luaC_runtilstate(L, bitmask(GCSpropagate));
}
g->gckind = origkind;
- luaE_setdebt(g, stddebt(g));
+ setpause(g, gettotalbytes(g));
if (!isemergency) /* do not run finalizers during emergency GC */
callallpendingfinalizers(L, 1);
}