commit 32d4f304db365599a54b3eb30377ac6e20846749
parent 4b12eff8017f5e005a483f8097cdd64e9723a514
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 24 Aug 2004 17:11:44 -0300
first implementation of generational GC
Diffstat:
7 files changed, 162 insertions(+), 159 deletions(-)
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.7 2004/04/30 20:13:38 roberto Exp roberto $
+** $Id: lgc.c,v 2.8 2004/08/10 19:17:23 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -25,10 +25,11 @@
#define GCSTEPSIZE (40*sizeof(TValue))
#define STEPMUL 2
-#define GCFREECOST (sizeof(TValue)/10)
-#define GCSWEEPCOST (sizeof(TValue)/20)
+#define GCSWEEPMAX 40
+#define GCSWEEPCOST 1
#define GCFINALIZECOST (10*sizeof(TValue))
-#define WAITNEXTCYCLE (10 * GCSTEPSIZE)
+#define WAITNEXTCYCLE (40 * GCSTEPSIZE)
+#define WAITNEXTCYCLEGN (200 * GCSTEPSIZE)
#define FIXEDMASK bitmask(FIXEDBIT)
@@ -269,60 +270,61 @@ static void traversestack (global_State *g, lua_State *l) {
/*
-** traverse a given `quantity' of gray objects,
-** turning them to black. Returns extra `quantity' traversed.
+** traverse one gray object, turning it to black.
+** Returns `quantity' traversed.
*/
-static l_mem propagatemarks (global_State *g, l_mem lim) {
- GCObject *o;
- while ((o = g->gray) != NULL) {
- lua_assert(isgray(o));
- gray2black(o);
- switch (o->gch.tt) {
- case LUA_TTABLE: {
- Table *h = gco2h(o);
- g->gray = h->gclist;
- if (traversetable(g, h)) /* table is weak? */
- black2gray(o); /* keep it gray */
- lim -= sizeof(Table) + sizeof(TValue) * h->sizearray +
- sizeof(Node) * sizenode(h);
- break;
- }
- case LUA_TFUNCTION: {
- Closure *cl = gco2cl(o);
- g->gray = cl->c.gclist;
- traverseclosure(g, cl);
- lim -= (cl->c.isC) ? sizeCclosure(cl->c.nupvalues) :
- sizeLclosure(cl->l.nupvalues);
- break;
- }
- case LUA_TTHREAD: {
- lua_State *th = gco2th(o);
- g->gray = th->gclist;
- th->gclist = g->grayagain;
- g->grayagain = o;
- black2gray(o);
- traversestack(g, th);
- lim -= sizeof(lua_State) + sizeof(TValue) * th->stacksize +
- sizeof(CallInfo) * th->size_ci;
- break;
- }
- case LUA_TPROTO: {
- Proto *p = gco2p(o);
- g->gray = p->gclist;
- traverseproto(g, p);
- lim -= sizeof(Proto) + sizeof(Instruction) * p->sizecode +
- sizeof(Proto *) * p->sizep +
- sizeof(TValue) * p->sizek +
- sizeof(int) * p->sizelineinfo +
- sizeof(LocVar) * p->sizelocvars +
- sizeof(TString *) * p->sizeupvalues;
- break;
- }
- default: lua_assert(0);
+static l_mem propagatemark (global_State *g) {
+ GCObject *o = g->gray;
+ lua_assert(isgray(o));
+ gray2black(o);
+ switch (o->gch.tt) {
+ case LUA_TTABLE: {
+ Table *h = gco2h(o);
+ g->gray = h->gclist;
+ if (traversetable(g, h)) /* table is weak? */
+ black2gray(o); /* keep it gray */
+ return sizeof(Table) + sizeof(TValue) * h->sizearray +
+ sizeof(Node) * sizenode(h);
+ break;
+ }
+ case LUA_TFUNCTION: {
+ Closure *cl = gco2cl(o);
+ g->gray = cl->c.gclist;
+ traverseclosure(g, cl);
+ return (cl->c.isC) ? sizeCclosure(cl->c.nupvalues) :
+ sizeLclosure(cl->l.nupvalues);
+ break;
}
- if (lim <= 0) return lim;
+ case LUA_TTHREAD: {
+ lua_State *th = gco2th(o);
+ g->gray = th->gclist;
+ th->gclist = g->grayagain;
+ g->grayagain = o;
+ black2gray(o);
+ traversestack(g, th);
+ return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
+ sizeof(CallInfo) * th->size_ci;
+ break;
+ }
+ case LUA_TPROTO: {
+ Proto *p = gco2p(o);
+ g->gray = p->gclist;
+ traverseproto(g, p);
+ return sizeof(Proto) + sizeof(Instruction) * p->sizecode +
+ sizeof(Proto *) * p->sizep +
+ sizeof(TValue) * p->sizek +
+ sizeof(int) * p->sizelineinfo +
+ sizeof(LocVar) * p->sizelocvars +
+ sizeof(TString *) * p->sizeupvalues;
+ break;
+ }
+ default: lua_assert(0); return 0;
}
- return lim;
+}
+
+
+static void propagateall (global_State *g) {
+ while (g->gray) propagatemark(g);
}
@@ -384,6 +386,7 @@ static void freeobj (lua_State *L, GCObject *o) {
break;
}
case LUA_TSTRING: {
+ G(L)->strt.nuse--;
luaM_free(L, o, sizestring(gco2ts(o)->len));
break;
}
@@ -396,59 +399,50 @@ static void freeobj (lua_State *L, GCObject *o) {
}
-static l_mem sweepwholelist (lua_State *L, GCObject **p, int keepfixed,
- lu_int32 *count);
+
+#define sweepwholelist(L,p) sweeplist(L,p,LUA_MAXINT32)
-static GCObject **sweeplist (lua_State *L, GCObject **p, int keepfixed,
- l_mem *plim, lu_int32 *count) {
+static GCObject **sweeplist (lua_State *L, GCObject **p, lu_int32 count) {
GCObject *curr;
global_State *g = G(L);
- l_mem lim = *plim;
- int deadmask = otherwhite(g);
- if (keepfixed) deadmask |= FIXEDMASK;
+ int whitebit = otherwhite(g);
+ int deadmask = whitebit | FIXEDMASK;
while ((curr = *p) != NULL) {
- if (((curr->gch.marked ^ FIXEDMASK) & deadmask) != deadmask) {
- makewhite(g, curr);
+ if ((curr->gch.marked ^ whitebit) & deadmask) {
+ lua_assert(!isdead(g, curr) || testbit(curr->gch.marked, FIXEDBIT));
+ if (!G(L)->gcgenerational || isdead(g, curr))
+ makewhite(g, curr);
if (curr->gch.tt == LUA_TTHREAD)
- lim -= sweepwholelist(L, &gco2th(curr)->openupval, keepfixed, count);
+ sweepwholelist(L, &gco2th(curr)->openupval);
p = &curr->gch.next;
- lim -= GCSWEEPCOST;
}
else {
- lua_assert(iswhite(curr));
+ lua_assert(isdead(g, curr));
*p = curr->gch.next;
if (curr == g->rootgc) /* is the first element of the list? */
g->rootgc = curr->gch.next; /* adjust first */
freeobj(L, curr);
- lim -= GCFREECOST;
- if (count) (*count)--;
}
- if (lim <= 0) break;
+ if (count-- == 0) break;
}
- *plim = lim;
return p;
}
-static l_mem sweepwholelist (lua_State *L, GCObject **p, int keepfixed,
- lu_int32 *count) {
- l_mem lim = MAXLMEM;
- /* empty lists are quite common here, so avoid useless calls */
- if (*p) sweeplist(L, p, keepfixed, &lim, count);
- return MAXLMEM - lim;
+static void sweepstrings (lua_State *L) {
+ global_State *g = G(L);
+ sweepwholelist(L, &G(L)->strt.hash[g->sweepstrgc++]);
}
-static l_mem sweepstrings (lua_State *L, int keepfixed, l_mem lim) {
- int i;
- global_State *g = G(L);
- for (i = g->sweepstrgc; i < g->strt.size; i++) { /* for each list */
- lim -= sweepwholelist(L, &G(L)->strt.hash[i], keepfixed, &g->strt.nuse);
- if (lim <= 0) break;
+static void freelist (lua_State *L, GCObject **p) {
+ while (*p) {
+ GCObject *curr = *p;
+ *p = (*p)->gch.next;
+ if (curr != obj2gco(L))
+ freeobj(L, curr);
}
- g->sweepstrgc = i+1;
- return lim;
}
@@ -497,19 +491,12 @@ void luaC_callGCTM (lua_State *L) {
}
-void luaC_sweepall (lua_State *L) {
+void luaC_freeall (lua_State *L) {
global_State *g = G(L);
- l_mem dummy = MAXLMEM;
- /* finish (occasional) current sweep */
- sweepstrings(L, 0, MAXLMEM);
- sweeplist(L, &g->rootgc, 0, &dummy, NULL);
- /* do a whole new sweep */
- markobject(g, g->mainthread); /* cannot collect main thread */
- g->currentwhite = otherwhite(g);
- g->sweepgc = &g->rootgc;
- g->sweepstrgc = 0;
- sweepstrings(L, 0, MAXLMEM);
- sweeplist(L, &g->rootgc, 0, &dummy, NULL);
+ int i;
+ freelist(L, &g->rootgc);
+ for (i = 0; i < g->strt.size; i++) /* free all string lists */
+ freelist(L, &G(L)->strt.hash[i]);
}
@@ -553,64 +540,68 @@ static void atomic (lua_State *L) {
g->weak = NULL;
lua_assert(!iswhite(obj2gco(g->mainthread)));
markobject(g, L); /* mark running thread */
- propagatemarks(g, MAXLMEM);
+ propagateall(g);
/* remark gray again */
g->gray = g->grayagain;
g->grayagain = NULL;
- propagatemarks(g, MAXLMEM);
+ propagateall(g);
luaC_separateudata(L, 0); /* separate userdata to be preserved */
marktmu(g); /* mark `preserved' userdata */
- propagatemarks(g, MAXLMEM); /* remark, to propagate `preserveness' */
+ propagateall(g); /* remark, to propagate `preserveness' */
cleartable(g->weak); /* remove collected objects from weak tables */
/* flip current white */
g->currentwhite = otherwhite(g);
+ g->sweepstrgc = 0;
+ g->sweepgc = &g->rootgc;
g->gcstate = GCSsweepstring;
+ if (g->gcgenerational++ > 20) g->gcgenerational = 0;
}
-static l_mem singlestep (lua_State *L, l_mem lim) {
+static l_mem singlestep (lua_State *L) {
global_State *g = G(L);
+ /*lua_checkmemory(L);*/
switch (g->gcstate) {
case GCSpropagate: {
if (g->gray)
- lim = propagatemarks(g, lim);
+ return propagatemark(g);
else { /* no more `gray' objects */
atomic(L); /* finish mark phase */
- lim = 0;
+ return 0;
}
- break;
}
case GCSsweepstring: {
- lim = sweepstrings(L, 1, lim);
- if (g->sweepstrgc >= g->strt.size) { /* nothing more to sweep? */
- g->sweepstrgc = 0;
+ sweepstrings(L);
+ if (g->sweepstrgc >= g->strt.size) /* nothing more to sweep? */
g->gcstate = GCSsweep; /* end sweep-string phase */
- }
- break;
+ return GCSWEEPCOST;
}
case GCSsweep: {
- g->sweepgc = sweeplist(L, g->sweepgc, 1, &lim, NULL);
+ g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
if (*g->sweepgc == NULL) { /* nothing more to sweep? */
checkSizes(L);
- g->sweepgc = &g->rootgc;
g->gcstate = GCSfinalize; /* end sweep phase */
}
- break;
+ return GCSWEEPCOST;
}
case GCSfinalize: {
if (g->tmudata) {
GCTM(L);
- lim -= GCFINALIZECOST;
+ return GCFINALIZECOST;
}
else { /* no more `udata' to finalize */
- markroot(L); /* may restart collection */
- lim = 0;
+ if (g->gcgenerational) {
+ atomic(L);
+ return WAITNEXTCYCLEGN;
+ }
+ else {
+ markroot(L); /* may restart collection */
+ return WAITNEXTCYCLE;
+ }
}
- break;
}
- default: lua_assert(0);
+ default: lua_assert(0); return 0;
}
- return lim;
}
@@ -618,11 +609,7 @@ void luaC_step (lua_State *L) {
global_State *g = G(L);
l_mem lim = (g->nblocks - (g->GCthreshold - GCSTEPSIZE)) * STEPMUL;
do {
- lim = singlestep(L, lim);
- if (g->gcstate == GCSfinalize && g->tmudata == NULL) {
- lim = -WAITNEXTCYCLE;
- break; /* do not start new collection */
- }
+ lim -= singlestep(L);
} while (lim > 0);
g->GCthreshold = g->nblocks + GCSTEPSIZE - lim/STEPMUL;
lua_assert((long)g->nblocks + (long)GCSTEPSIZE >= lim/STEPMUL);
@@ -631,12 +618,26 @@ void luaC_step (lua_State *L) {
void luaC_fullgc (lua_State *L) {
global_State *g = G(L);
+ if (g->gcstate == GCSpropagate || g->gcgenerational) {
+ g->gcgenerational = 0;
+ /* reset sweep marks to sweep all elements (returning them to white) */
+ g->sweepstrgc = 0;
+ g->sweepgc = &g->rootgc;
+ /* reset other collector lists */
+ g->gray = NULL;
+ g->grayagain = NULL;
+ g->weak = NULL;
+ g->gcstate = GCSsweepstring;
+ }
+ /* finish any pending sweep phase */
while (g->gcstate != GCSfinalize) {
- singlestep(L, MAXLMEM);
+ singlestep(L);
}
markroot(L);
+ lua_assert(!g->gcgenerational);
while (g->gcstate != GCSfinalize) {
- singlestep(L, MAXLMEM);
+ singlestep(L);
+ g->gcgenerational = 0; /* keep it in this mode */
}
g->GCthreshold = g->nblocks + GCSTEPSIZE;
luaC_callGCTM(L); /* call finalizers */
@@ -646,7 +647,7 @@ void luaC_fullgc (lua_State *L) {
void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v) {
global_State *g = G(L);
lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
- lua_assert(g->gcstate != GCSfinalize);
+ lua_assert(g->gcgenerational || g->gcstate != GCSfinalize);
if (g->gcstate != GCSpropagate) /* sweeping phases? */
black2gray(o); /* just mark as gray to avoid other barriers */
else /* breaking invariant! */
@@ -657,7 +658,7 @@ void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v) {
void luaC_barrierback (lua_State *L, GCObject *o, GCObject *v) {
global_State *g = G(L);
lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
- lua_assert(g->gcstate != GCSfinalize);
+ lua_assert(g->gcgenerational || g->gcstate != GCSfinalize);
black2gray(o); /* make table gray (again) */
gco2h(o)->gclist = g->grayagain;
g->grayagain = o;
@@ -679,7 +680,7 @@ void luaC_linkupval (lua_State *L, UpVal *uv) {
o->gch.next = g->rootgc; /* link upvalue into `rootgc' list */
g->rootgc = o;
if (isgray(o)) {
- if (g->gcstate == GCSpropagate) {
+ if (g->gcstate == GCSpropagate || g->gcgenerational) {
gray2black(o); /* closed upvalues need barrier */
luaC_barrier(L, uv, uv->v);
}
diff --git a/lgc.h b/lgc.h
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.h,v 2.5 2004/03/15 21:04:33 roberto Exp roberto $
+** $Id: lgc.h,v 2.6 2004/08/10 19:17:23 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -39,12 +39,13 @@
/*
** Layout for bit use in `marked' field:
-** bit 0 - object is gray
-** bit 1 - object is black
-** bit 2 - For userdata: is finalized;
- for tables: has weak keys
-** bit 3 - for tables: has weak values
-** bit 4 - object is fixed (should not be collected)
+** bit 0 - object is white (type 0)
+** bit 1 - object is white (type 1)
+** bit 2 - object is black
+** bit 3 - for userdata: has been finalized
+** bit 3 - for tables: has weak keys
+** bit 4 - for tables: has weak values
+** bit 5 - object is fixed (should not be collected)
*/
#define WHITE0BIT 0
@@ -86,7 +87,7 @@
size_t luaC_separateudata (lua_State *L, int all);
void luaC_callGCTM (lua_State *L);
-void luaC_sweepall (lua_State *L);
+void luaC_freeall (lua_State *L);
void luaC_step (lua_State *L);
void luaC_fullgc (lua_State *L);
void luaC_link (lua_State *L, GCObject *o, lu_byte tt);
diff --git a/lstate.c b/lstate.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.c,v 2.9 2004/06/17 14:06:52 roberto Exp roberto $
+** $Id: lstate.c,v 2.10 2004/06/17 14:25:31 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -122,9 +122,10 @@ static void preinit_state (lua_State *L, global_State *g) {
static void close_state (lua_State *L) {
global_State *g = G(L);
luaF_close(L, L->stack); /* close all upvalues for this thread */
- luaC_sweepall(L); /* collect all elements */
- lua_assert(g->rootgc == obj2gco(L));
- luaS_freeall(L);
+ luaC_freeall(L); /* collect all objects */
+ lua_assert(g->rootgc == NULL);
+ lua_assert(g->strt.nuse == 0);
+ luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
luaZ_freebuffer(L, &g->buff);
freestack(L, L);
lua_assert(g->nblocks == sizeof(LG));
@@ -177,6 +178,7 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
luaZ_initbuffer(L, &g->buff);
g->panic = NULL;
g->gcstate = GCSfinalize;
+ g->gcgenerational = 0;
g->rootgc = obj2gco(L);
g->sweepstrgc = 0;
g->sweepgc = &g->rootgc;
diff --git a/lstate.h b/lstate.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.h,v 2.4 2004/05/31 18:51:50 roberto Exp roberto $
+** $Id: lstate.h,v 2.5 2004/06/02 19:07:55 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -69,7 +69,9 @@ typedef struct global_State {
stringtable strt; /* hash table for strings */
lua_Alloc realloc; /* function to reallocate memory */
void *ud; /* auxiliary data to `realloc' */
- int currentwhite;
+ lu_byte currentwhite;
+ lu_byte gcstate; /* state of garbage collector */
+ lu_byte gcgenerational;
GCObject *rootgc; /* list of all collectable objects */
GCObject *firstudata; /* udata go to the end of `rootgc' */
GCObject **sweepgc; /* position of sweep in `rootgc' */
@@ -78,7 +80,6 @@ typedef struct global_State {
GCObject *grayagain; /* list of objects to be traversed atomically */
GCObject *weak; /* list of weak tables (to be cleared) */
GCObject *tmudata; /* list of userdata to be GC */
- int gcstate; /* state of garbage collector */
Mbuffer buff; /* temporary buffer for string concatentation */
lu_mem GCthreshold;
lu_mem nblocks; /* number of `bytes' currently allocated */
diff --git a/lstring.c b/lstring.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.c,v 2.1 2003/12/10 12:13:36 roberto Exp roberto $
+** $Id: lstring.c,v 2.2 2004/04/30 20:13:38 roberto Exp roberto $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -19,17 +19,12 @@
-void luaS_freeall (lua_State *L) {
- lua_assert(G(L)->strt.nuse==0);
- luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
-}
-
-
void luaS_resize (lua_State *L, int newsize) {
GCObject **newhash;
stringtable *tb;
int i;
- if (G(L)->sweepstrgc > 0) return; /* cannot resize during GC traverse */
+ if (G(L)->gcstate == GCSsweepstring)
+ return; /* cannot resize during GC traverse */
newhash = luaM_newvector(L, newsize, GCObject *);
tb = &G(L)->strt;
for (i=0; i<newsize; i++) newhash[i] = NULL;
diff --git a/lstring.h b/lstring.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstring.h,v 1.37 2002/08/16 14:45:55 roberto Exp roberto $
+** $Id: lstring.h,v 1.38 2003/11/17 19:50:05 roberto Exp roberto $
** String table (keep all strings handled by Lua)
** See Copyright Notice in lua.h
*/
@@ -26,7 +26,6 @@
void luaS_resize (lua_State *L, int newsize);
Udata *luaS_newudata (lua_State *L, size_t s);
-void luaS_freeall (lua_State *L);
TString *luaS_newlstr (lua_State *L, const char *str, size_t l);
diff --git a/ltests.c b/ltests.c
@@ -1,5 +1,5 @@
/*
-** $Id: ltests.c,v 2.9 2004/06/02 19:08:52 roberto Exp roberto $
+** $Id: ltests.c,v 2.10 2004/07/09 18:23:17 roberto Exp roberto $
** Internal Module for Debugging of the Lua Implementation
** See Copyright Notice in lua.h
*/
@@ -153,9 +153,9 @@ void *debug_realloc (void *ud, void *block, size_t oldsize, size_t size) {
static int testobjref1 (global_State *g, GCObject *f, GCObject *t) {
if (isdead(g,t)) return 0;
- if (g->gcstate == GCSpropagate)
+ if (g->gcstate == GCSpropagate || g->gcgenerational)
return !isblack(f) || !iswhite(t);
- else if (g->gcstate == GCSfinalize)
+ else if (g->gcstate == GCSfinalize && !g->gcgenerational)
return iswhite(f);
else
return 1;
@@ -175,7 +175,8 @@ static void printobj (global_State *g, GCObject *o) {
static int testobjref (global_State *g, GCObject *f, GCObject *t) {
int r = testobjref1(g,f,t);
if (!r) {
- printf("%d(%02X) - ", g->gcstate, g->currentwhite);
+ printf("%d(%02X) %c - ", g->gcstate, g->currentwhite,
+ g->gcgenerational ? 'G' : ' ');
printobj(g, f);
printf("\t-> ");
printobj(g, t);
@@ -290,9 +291,12 @@ static void checkstack (global_State *g, lua_State *L1) {
static void checkobject (global_State *g, GCObject *o) {
if (isdead(g, o))
- lua_assert(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);
+/* lua_assert(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);*/
+{ if (!(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep))
+printf(">>> %d %s %02x\n", g->gcstate, luaT_typenames[o->gch.tt], o->gch.marked);
+}
else {
- if (g->gcstate == GCSfinalize)
+ if (g->gcstate == GCSfinalize && !g->gcgenerational)
lua_assert(iswhite(o));
switch (o->gch.tt) {
case LUA_TUPVAL: {
