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BUG: emergency collector might resize 'strt' (string table) when

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creating a new string
+ atomic and markroot steps has some cost
+ full collection must leave collector in proper state when mode
is generational
This commit is contained in:
Roberto Ierusalimschy 2010-03-23 17:16:06 -03:00
parent 74123e9686
commit 5cb128ea54
1 changed files with 27 additions and 11 deletions
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38
lgc.c
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@ -1,5 +1,5 @@
/*
** $Id: lgc.c,v 2.67 2009/12/22 15:32:50 roberto Exp roberto $
** $Id: lgc.c,v 2.68 2010/03/22 18:28:03 roberto Exp $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@ -27,6 +27,8 @@
#define GCSWEEPMAX 40
#define GCSWEEPCOST 10
#define GCFINALIZECOST 100
#define GCROOTCOST 10
#define GCATOMICCOST 1000
#define maskcolors (~(bitmask(BLACKBIT)|WHITEBITS))
@ -580,6 +582,8 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
static void checkSizes (lua_State *L) {
global_State *g = G(L);
if (g->gckind == KGC_EMERGENCY)
return; /* do not move buffers during emergency collection */
if (g->strt.nuse < cast(lu_int32, g->strt.size)) {
/* string-table size could be the smaller power of 2 larger than 'nuse' */
int size = 1 << luaO_ceillog2(g->strt.nuse);
@ -739,7 +743,7 @@ static l_mem singlestep (lua_State *L) {
case GCSpause: {
markroot(L); /* start a new collection */
g->gcstate = GCSpropagate;
return 0;
return GCROOTCOST;
}
case GCSpropagate: {
if (g->gray)
@ -748,22 +752,30 @@ static l_mem singlestep (lua_State *L) {
g->gcstate = GCSatomic; /* finish mark phase */
atomic(L);
g->gcstate = GCSsweepstring;
return 0;
return GCATOMICCOST;
}
}
case GCSsweepstring: {
sweepwholelist(L, &g->strt.hash[g->sweepstrgc++]);
if (g->sweepstrgc >= g->strt.size) { /* nothing more to sweep? */
if (g->sweepstrgc < g->strt.size) {
sweepwholelist(L, &g->strt.hash[g->sweepstrgc++]);
return GCSWEEPCOST;
}
else { /* nothing more to sweep */
g->sweepgc = &g->rootgc;
g->gcstate = GCSsweep; /* sweep all other objects */
return 0;
}
return GCSWEEPCOST;
}
case GCSsweep: {
g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
if (*g->sweepgc == NULL) /* nothing more to sweep? */
if (*g->sweepgc) {
g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
return GCSWEEPMAX*GCSWEEPCOST;
}
else { /* nothing more to sweep */
checkSizes(L);
g->gcstate = GCSfinalize; /* end sweep phase */
return GCSWEEPMAX*GCSWEEPCOST;
return 0;
}
}
case GCSfinalize: {
if (g->tobefnz) {
@ -771,7 +783,6 @@ static l_mem singlestep (lua_State *L) {
return GCFINALIZECOST;
}
else {
checkSizes(L);
g->gcstate = GCSpause; /* end collection */
return 0;
}
@ -840,18 +851,23 @@ void luaC_fullgc (lua_State *L, int isemergency) {
g->gckind = isemergency ? KGC_EMERGENCY : KGC_FORCED;
if (g->gcstate == GCSpropagate) { /* marking phase? */
/* must sweep all objects to turn them back to white
(as white does not change, nothing will be collected) */
(as white has not changed, nothing will be collected) */
g->sweepstrgc = 0;
g->gcstate = GCSsweepstring;
}
/* finish any pending sweep phase */
luaC_runtilstate(L, ~bit2mask(GCSsweepstring, GCSsweep));
lua_assert(g->gcstate == GCSpause || g->gcstate == GCSfinalize);
g->gcstate = GCSpause; /* start a new collection */
/* run collector up to finalizers */
luaC_runtilstate(L, bitmask(GCSfinalize));
g->gckind = origkind;
if (!isemergency) /* do not run finalizers during emergency GC */
luaC_runtilstate(L, bitmask(GCSpause));
if (origkind == KGC_GEN) { /* generational mode? */
g->gckind = GCSpause; /* collector must be always in... */
luaC_runtilstate(L, bitmask(GCSpropagate)); /* ...propagate phase */
}
g->GCthreshold = (g->totalbytes/100) * g->gcpause;
}