static void generationalcollection (lua_State *L) {
global_State *g = G(L);
if (g->lastmajormem == 0) { /* signal for another major collection? */
luaC_fullgc(L, 0); /* perform a full regular collection */
g->lastmajormem = gettotalbytes(g); /* update control */
}
else {
luaC_runtilstate(L, ~bitmask(GCSpause)); /* run complete cycle */
luaC_runtilstate(L, bitmask(GCSpause));
if (gettotalbytes(g) > g->lastmajormem/100 * g->gcmajorinc)
g->lastmajormem = 0; /* signal for a major collection */
}
luaE_setdebt(g, stddebt(g));
}
/*
** performs a full GC cycle; if "isemergency", does not call
** finalizers (which could change stack positions)
*/
void luaC_fullgc (lua_State *L, int isemergency) {
global_State *g = G(L);
int origkind = g->gckind;
lua_assert(origkind != KGC_EMERGENCY);
if (isemergency) /* do not run finalizers during emergency GC */
g->gckind = KGC_EMERGENCY;
else {
g->gckind = KGC_NORMAL;
callallpendingfinalizers(L, 1);
}
if (keepinvariant(g)) { /* may there be some black objects? */
/* must sweep all objects to turn them back to white
(as white has not changed, nothing will be collected) */
entersweep(L);
}
/* finish any pending sweep phase to start a new cycle */
luaC_runtilstate(L, bitmask(GCSpause));
luaC_runtilstate(L, ~bitmask(GCSpause)); /* start new collection */
luaC_runtilstate(L, bitmask(GCSpause)); /* run entire collection */
if (origkind == KGC_GEN) { /* generational mode? */
/* generational mode must be kept in propagate phase */
luaC_runtilstate(L, bitmask(GCSpropagate));
}
g->gckind = origkind;
setpause(g, gettotalbytes(g));
if (!isemergency) /* do not run finalizers during emergency GC */
callallpendingfinalizers(L, 1);
}
/*
** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
** invariant (and avoiding underflows in 'totalbytes')
*/
void luaE_setdebt (global_State *g, l_mem debt) {
l_mem tb = gettotalbytes(g);
lua_assert(tb > 0);
if (debt < tb - MAX_LMEM)
debt = tb - MAX_LMEM; /* will make 'totalbytes == MAX_LMEM' */
g->totalbytes = tb - debt;
g->GCdebt = debt;
}
/*
** 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);
}
/*
** 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 threshold, debt;
l_mem estimate = g->GCestimate / PAUSEADJ; /* adjust 'estimate' */
threshold = (g->gcpause < MAX_LMEM / estimate) /* overflow? */
? estimate * g->gcpause /* no overflow */
: MAX_LMEM; /* overflow; truncate to maximum */
debt = gettotalbytes(g) - threshold;
luaE_setdebt(g, debt);
}
static lu_mem singlestep (lua_State *L) {
global_State *g = G(L);
switch (g->gcstate) {
case GCSpause: {
g->GCmemtrav = g->strt.size * sizeof(GCObject*);
restartcollection(g);
g->gcstate = GCSpropagate;
return g->GCmemtrav;
}
case GCSpropagate: {
g->GCmemtrav = 0;
lua_assert(g->gray);
propagatemark(g);
if (g->gray == NULL) /* no more gray objects? */
g->gcstate = GCSatomic; /* finish propagate phase */
return g->GCmemtrav; /* memory traversed in this step */
}
case GCSatomic: {
lu_mem work;
int sw;
propagateall(g); /* make sure gray list is empty */
work = atomic(L); /* work is what was traversed by 'atomic' */
sw = entersweep(L);
g->GCestimate = gettotalbytes(g); /* first estimate */;
return work + sw * GCSWEEPCOST;
}
case GCSswpallgc: { /* sweep "regular" objects */
return sweepstep(L, g, GCSswpfinobj, &g->finobj);
}
case GCSswpfinobj: { /* sweep objects with finalizers */
return sweepstep(L, g, GCSswptobefnz, &g->tobefnz);
}
case GCSswptobefnz: { /* sweep objects to be finalized */
return sweepstep(L, g, GCSswpend, NULL);
}
case GCSswpend: { /* finish sweeps */
makewhite(g, g->mainthread); /* sweep main thread */
checkSizes(L, g);
g->gcstate = GCScallfin;
return 0;
}
case GCScallfin: { /* call remaining finalizers */
if (g->tobefnz && g->gckind != KGC_EMERGENCY) {
int n = runafewfinalizers(L);
return (n * GCFINALIZECOST);
}
else { /* emergency mode or no more finalizers */
g->gcstate = GCSpause; /* finish collection */
return 0;
}
}
default:
lua_assert(0);
return 0;
}
}
static void close_state (lua_State *L) {
global_State *g = G(L);
luaF_close(L, L->stack); /* close all upvalues for this thread */
luaC_freeallobjects(L); /* collect all objects */
luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
luaZ_freebuffer(L, &g->buff);
freestack(L);
lua_assert(gettotalbytes(g) == sizeof(LG));
(*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */
}
static void generationalcollection (lua_State *L) {
global_State *g = G(L);
lua_assert(g->gcstate == GCSpropagate);
if (g->GCestimate == 0) { /* signal for another major collection? */
luaC_fullgc(L, 0); /* perform a full regular collection */
g->GCestimate = gettotalbytes(g); /* update control */
}
else {
lu_mem estimate = g->GCestimate;
luaC_runtilstate(L, bitmask(GCSpause)); /* run complete (minor) cycle */
g->gcstate = GCSpropagate; /* skip restart */
if (gettotalbytes(g) > (estimate / 100) * g->gcmajorinc)
g->GCestimate = 0; /* signal for a major collection */
else
g->GCestimate = estimate; /* keep estimate from last major coll. */
}
setpause(g, gettotalbytes(g));
lua_assert(g->gcstate == GCSpropagate);
}
static void close_state (lua_State *L) {
global_State *g = G(L);
luaF_close(L, L->stack); /* close all upvalues for this thread */
luaC_freeallobjects(L); /* collect all objects */
if (g->version) /* closing a fully built state? */
luai_userstateclose(L);
luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
freestack(L);
lua_assert(gettotalbytes(g) == sizeof(LG));
(*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */
}
/*
** Performs a full GC cycle; if 'isemergency', set a flag to avoid
** some operations which could change the interpreter state in some
** unexpected ways (running finalizers and shrinking some structures).
** Before running the collection, check 'keepinvariant'; if it is true,
** there may be some objects marked as black, so the collector has
** to sweep all objects to turn them back to white (as white has not
** changed, nothing will be collected).
*/
void luaC_fullgc (lua_State *L, int isemergency) {
global_State *g = G(L);
lua_assert(g->gckind == KGC_NORMAL);
if (isemergency) g->gckind = KGC_EMERGENCY; /* set flag */
if (keepinvariant(g)) { /* black objects? */
entersweep(L); /* sweep everything to turn them back to white */
}
/* finish any pending sweep phase to start a new cycle */
luaC_runtilstate(L, bitmask(GCSpause));
luaC_runtilstate(L, ~bitmask(GCSpause)); /* start new collection */
luaC_runtilstate(L, bitmask(GCScallfin)); /* run up to finalizers */
/* estimate must be correct after a full GC cycle */
lua_assert(g->GCestimate == gettotalbytes(g));
luaC_runtilstate(L, bitmask(GCSpause)); /* finish collection */
g->gckind = KGC_NORMAL;
setpause(g);
}
/*
** change GC mode
*/
void luaC_changemode (lua_State *L, int mode) {
global_State *g = G(L);
if (mode == g->gckind) return; /* nothing to change */
if (mode == KGC_GEN) { /* change to generational mode */
/* make sure gray lists are consistent */
luaC_runtilstate(L, bitmask(GCSpropagate));
g->GCestimate = gettotalbytes(g);
g->gckind = KGC_GEN;
}
else { /* change to incremental mode */
/* sweep all objects to turn them back to white
(as white has not changed, nothing extra will be collected) */
g->gckind = KGC_NORMAL;
entersweep(L);
luaC_runtilstate(L, ~sweepphases);
}
}
/*
** generic allocation routine.
*/
void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
void *newblock;
global_State *g = G(L);
size_t realosize = (block) ? osize : 0;
lua_assert((realosize == 0) == (block == NULL));
#if defined(HARDMEMTESTS)
if (nsize > realosize && g->gcrunning)
luaC_fullgc(L, 1); /* force a GC whenever possible */
#endif
newblock = (*g->frealloc)(g->ud, block, osize, nsize);
if (newblock == NULL && nsize > 0) {
api_check(L, nsize > realosize,
"realloc cannot fail when shrinking a block");
if (g->gcrunning) {
luaC_fullgc(L, 1); /* try to free some memory... */
newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */
}
if (newblock == NULL)
luaD_throw(L, LUA_ERRMEM);
}
lua_assert((nsize == 0) == (newblock == NULL));
g->GCdebt = (g->GCdebt + nsize) - realosize;
#if defined(TRACEMEM)
{ /* auxiliary patch to monitor garbage collection.
** To plot, gnuplot with following command:
** plot TRACEMEM using 1:2 with lines, TRACEMEM using 1:3 with lines
*/
static unsigned long total = 0; /* our "time" */
static FILE *f = NULL; /* output file */
total++; /* "time" always grows */
if ((total % 200) == 0) {
if (f == NULL) f = fopen(TRACEMEM, "w");
fprintf(f, "%lu %u %d %d\n", total,
gettotalbytes(g), g->GCdebt, g->gcstate * 10000);
}
}
#endif
return newblock;
}
