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emergency garbage collector (core forces a GC when allocation fails)

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This commit is contained in:
Roberto Ierusalimschy
2006-07-11 12:53:29 -03:00
parent c7b89dd280
commit 3ca9af51a4
19 changed files with 190 additions and 153 deletions
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76
lgc.c
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@@ -1,5 +1,5 @@
/*
** $Id: lgc.c,v 2.37 2005/12/22 16:19:56 roberto Exp roberto $
** $Id: lgc.c,v 2.38 2006/05/24 14:34:06 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -52,7 +52,7 @@
#define markvalue(g,o) { checkconsistency(o); \
if (iscollectable(o) && iswhite(gcvalue(o))) reallymarkobject(g,gcvalue(o)); }
#define markobject(g,t) { if (iswhite(obj2gco(t))) \
#define markobject(g,t) { if ((t) && iswhite(obj2gco(t))) \
reallymarkobject(g, obj2gco(t)); }
@@ -76,7 +76,7 @@ static void reallymarkobject (global_State *g, GCObject *o) {
case LUA_TUSERDATA: {
Table *mt = gco2u(o)->metatable;
gray2black(o); /* udata are never gray */
if (mt) markobject(g, mt);
markobject(g, mt);
markobject(g, gco2u(o)->env);
return;
}
@@ -160,8 +160,7 @@ static int traversetable (global_State *g, Table *h) {
int weakkey = 0;
int weakvalue = 0;
const TValue *mode;
if (h->metatable)
markobject(g, h->metatable);
markobject(g, h->metatable);
mode = gfasttm(g, h->metatable, TM_MODE);
if (mode && ttisstring(mode)) { /* is there a weak mode? */
weakkey = (strchr(svalue(mode), 'k') != NULL);
@@ -209,10 +208,8 @@ static void traverseproto (global_State *g, Proto *f) {
if (f->upvalues[i])
stringmark(f->upvalues[i]);
}
for (i=0; i<f->sizep; i++) { /* mark nested protos */
if (f->p[i])
markobject(g, f->p[i]);
}
for (i=0; i<f->sizep; i++) /* mark nested protos */
markobject(g, f->p[i]);
for (i=0; i<f->sizelocvars; i++) { /* mark local-variable names */
if (f->locvars[i].varname)
stringmark(f->locvars[i].varname);
@@ -256,6 +253,8 @@ static void checkstacksizes (lua_State *L, StkId max) {
static void traversestack (global_State *g, lua_State *l) {
StkId o, lim;
CallInfo *ci;
if (l->stack == NULL || l->base_ci == NULL)
return; /* stack not completely built yet */
markvalue(g, gt(l));
lim = l->top;
for (ci = l->base_ci; ci <= l->ci; ci++) {
@@ -266,7 +265,8 @@ static void traversestack (global_State *g, lua_State *l) {
markvalue(g, o);
for (; o <= lim; o++)
setnilvalue(o);
checkstacksizes(l, lim);
if (!g->emergencygc) /* cannot change stack in emergency... */
checkstacksizes(l, lim); /* ...(interpreter does not expect that change) */
}
@@ -442,11 +442,9 @@ static void checkSizes (lua_State *L) {
}
static void GCTM (lua_State *L) {
global_State *g = G(L);
static Udata *udata2finalize (global_State *g) {
GCObject *o = g->tmudata->gch.next; /* get first element */
Udata *udata = rawgco2u(o);
const TValue *tm;
/* remove udata from `tmudata' */
if (o == g->tmudata) /* last element? */
g->tmudata = NULL;
@@ -455,7 +453,14 @@ static void GCTM (lua_State *L) {
udata->uv.next = g->mainthread->next; /* return it to `root' list */
g->mainthread->next = o;
makewhite(g, o);
tm = fasttm(L, udata->uv.metatable, TM_GC);
return udata;
}
static void GCTM (lua_State *L) {
global_State *g = G(L);
Udata *udata = udata2finalize(g);
const TValue *tm = fasttm(L, udata->uv.metatable, TM_GC);
if (tm != NULL) {
lu_byte oldah = L->allowhook;
lu_mem oldt = g->GCthreshold;
@@ -475,8 +480,17 @@ static void GCTM (lua_State *L) {
** Call all GC tag methods
*/
void luaC_callGCTM (lua_State *L) {
while (G(L)->tmudata)
global_State *g = G(L);
GCObject *last = g->tmudata;
GCObject *curr;
if (last == NULL) return; /* empty list? */
do {
curr = g->tmudata->gch.next; /* element to be collected */
GCTM(L);
} while (curr != last); /* go only until original last */
/* do not finalize new udata created during previous finalizations */
while (g->tmudata)
udata2finalize(g); /* simply remove them from list */
}
@@ -493,7 +507,7 @@ void luaC_freeall (lua_State *L) {
static void markmt (global_State *g) {
int i;
for (i=0; i<NUM_TAGS; i++)
if (g->mt[i]) markobject(g, g->mt[i]);
markobject(g, g->mt[i]);
}
@@ -553,6 +567,10 @@ static void atomic (lua_State *L) {
}
#define correctestimate(g,s) {lu_mem old = g->totalbytes; s; \
lua_assert(old >= g->totalbytes); g->estimate -= old - g->totalbytes;}
static l_mem singlestep (lua_State *L) {
global_State *g = G(L);
/*lua_checkmemory(L);*/
@@ -570,23 +588,15 @@ static l_mem singlestep (lua_State *L) {
}
}
case GCSsweepstring: {
lu_mem old = g->totalbytes;
sweepwholelist(L, &g->strt.hash[g->sweepstrgc++]);
correctestimate(g, sweepwholelist(L, &g->strt.hash[g->sweepstrgc++]));
if (g->sweepstrgc >= g->strt.size) /* nothing more to sweep? */
g->gcstate = GCSsweep; /* end sweep-string phase */
lua_assert(old >= g->totalbytes);
g->estimate -= old - g->totalbytes;
return GCSWEEPCOST;
}
case GCSsweep: {
lu_mem old = g->totalbytes;
g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
if (*g->sweepgc == NULL) { /* nothing more to sweep? */
checkSizes(L);
correctestimate(g, g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX));
if (*g->sweepgc == NULL) /* nothing more to sweep? */
g->gcstate = GCSfinalize; /* end sweep phase */
}
lua_assert(old >= g->totalbytes);
g->estimate -= old - g->totalbytes;
return GCSWEEPMAX*GCSWEEPCOST;
}
case GCSfinalize: {
@@ -597,6 +607,7 @@ static l_mem singlestep (lua_State *L) {
return GCFINALIZECOST;
}
else {
correctestimate(g, checkSizes(L));
g->gcstate = GCSpause; /* end collection */
g->gcdept = 0;
return 0;
@@ -610,6 +621,7 @@ static l_mem singlestep (lua_State *L) {
void luaC_step (lua_State *L) {
global_State *g = G(L);
l_mem lim = (GCSTEPSIZE/100) * g->gcstepmul;
lua_assert(!g->emergencygc);
if (lim == 0)
lim = (MAX_LUMEM-1)/2; /* no limit */
g->gcdept += g->totalbytes - g->GCthreshold;
@@ -633,8 +645,10 @@ void luaC_step (lua_State *L) {
}
void luaC_fullgc (lua_State *L) {
void luaC_fullgc (lua_State *L, int isemergency) {
int stopstate;
global_State *g = G(L);
g->emergencygc = isemergency;
if (g->gcstate <= GCSpropagate) {
/* reset sweep marks to sweep all elements (returning them to white) */
g->sweepstrgc = 0;
@@ -652,10 +666,12 @@ void luaC_fullgc (lua_State *L) {
singlestep(L);
}
markroot(L);
while (g->gcstate != GCSpause) {
/* do not run finalizers during emergency GC */
stopstate = isemergency ? GCSfinalize : GCSpause;
while (g->gcstate != stopstate)
singlestep(L);
}
setthreshold(g);
g->emergencygc = 0;
}