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-rw-r--r--3rdparty/lua/src/lgc.c873
1 files changed, 406 insertions, 467 deletions
diff --git a/3rdparty/lua/src/lgc.c b/3rdparty/lua/src/lgc.c
index 52460dcdd5a..8b95fb67da0 100644
--- a/3rdparty/lua/src/lgc.c
+++ b/3rdparty/lua/src/lgc.c
@@ -1,14 +1,17 @@
/*
-** $Id: lgc.c,v 2.140.1.2 2013/04/26 18:22:05 roberto Exp $
+** $Id: lgc.c,v 2.201 2014/12/20 13:58:15 roberto Exp $
** Garbage Collector
** See Copyright Notice in lua.h
*/
-#include <string.h>
-
#define lgc_c
#define LUA_CORE
+#include "lprefix.h"
+
+
+#include <string.h>
+
#include "lua.h"
#include "ldebug.h"
@@ -23,6 +26,11 @@
#include "ltm.h"
+/*
+** internal state for collector while inside the atomic phase. The
+** collector should never be in this state while running regular code.
+*/
+#define GCSinsideatomic (GCSpause + 1)
/*
** cost of sweeping one element (the size of a small object divided
@@ -33,8 +41,8 @@
/* maximum number of elements to sweep in each single step */
#define GCSWEEPMAX (cast_int((GCSTEPSIZE / GCSWEEPCOST) / 4))
-/* maximum number of finalizers to call in each GC step */
-#define GCFINALIZENUM 4
+/* cost of calling one finalizer */
+#define GCFINALIZECOST GCSWEEPCOST
/*
@@ -52,18 +60,18 @@
/*
-** 'makewhite' erases all color bits plus the old bit and then
-** sets only the current white bit
+** 'makewhite' erases all color bits then sets only the current white
+** bit
*/
-#define maskcolors (~(bit2mask(BLACKBIT, OLDBIT) | WHITEBITS))
+#define maskcolors (~(bitmask(BLACKBIT) | WHITEBITS))
#define makewhite(g,x) \
- (gch(x)->marked = cast_byte((gch(x)->marked & maskcolors) | luaC_white(g)))
+ (x->marked = cast_byte((x->marked & maskcolors) | luaC_white(g)))
-#define white2gray(x) resetbits(gch(x)->marked, WHITEBITS)
-#define black2gray(x) resetbit(gch(x)->marked, BLACKBIT)
+#define white2gray(x) resetbits(x->marked, WHITEBITS)
+#define black2gray(x) resetbit(x->marked, BLACKBIT)
-#define isfinalized(x) testbit(gch(x)->marked, FINALIZEDBIT)
+#define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x)))
#define checkdeadkey(n) lua_assert(!ttisdeadkey(gkey(n)) || ttisnil(gval(n)))
@@ -75,8 +83,8 @@
#define markvalue(g,o) { checkconsistency(o); \
if (valiswhite(o)) reallymarkobject(g,gcvalue(o)); }
-#define markobject(g,t) { if ((t) && iswhite(obj2gco(t))) \
- reallymarkobject(g, obj2gco(t)); }
+#define markobject(g,t) \
+ { if ((t) && iswhite(t)) reallymarkobject(g, obj2gco(t)); }
static void reallymarkobject (global_State *g, GCObject *o);
@@ -95,9 +103,9 @@ static void reallymarkobject (global_State *g, GCObject *o);
/*
-** link table 'h' into list pointed by 'p'
+** link collectable object 'o' into list pointed by 'p'
*/
-#define linktable(h,p) ((h)->gclist = *(p), *(p) = obj2gco(h))
+#define linkgclist(o,p) ((o)->gclist = (p), (p) = obj2gco(o))
/*
@@ -107,21 +115,21 @@ static void reallymarkobject (global_State *g, GCObject *o);
static void removeentry (Node *n) {
lua_assert(ttisnil(gval(n)));
if (valiswhite(gkey(n)))
- setdeadvalue(gkey(n)); /* unused and unmarked key; remove it */
+ setdeadvalue(wgkey(n)); /* unused and unmarked key; remove it */
}
/*
** tells whether a key or value can be cleared from a weak
** table. Non-collectable objects are never removed from weak
-** tables. Strings behave as `values', so are never removed too. for
+** tables. Strings behave as 'values', so are never removed too. for
** other objects: if really collected, cannot keep them; for objects
** being finalized, keep them in keys, but not in values
*/
static int iscleared (global_State *g, const TValue *o) {
if (!iscollectable(o)) return 0;
else if (ttisstring(o)) {
- markobject(g, rawtsvalue(o)); /* strings are `values', so are never weak */
+ markobject(g, tsvalue(o)); /* strings are 'values', so are never weak */
return 0;
}
else return iswhite(gcvalue(o));
@@ -130,14 +138,14 @@ static int iscleared (global_State *g, const TValue *o) {
/*
** barrier that moves collector forward, that is, mark the white object
-** being pointed by a black object.
+** being pointed by a black object. (If in sweep phase, clear the black
+** object to white [sweep it] to avoid other barrier calls for this
+** same object.)
*/
void luaC_barrier_ (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 != GCSpause);
- lua_assert(gch(o)->tt != LUA_TTABLE);
- if (keepinvariantout(g)) /* must keep invariant? */
+ if (keepinvariant(g)) /* must keep invariant? */
reallymarkobject(g, v); /* restore invariant */
else { /* sweep phase */
lua_assert(issweepphase(g));
@@ -148,78 +156,52 @@ void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v) {
/*
** barrier that moves collector backward, that is, mark the black object
-** pointing to a white object as gray again. (Current implementation
-** only works for tables; access to 'gclist' is not uniform across
-** different types.)
+** pointing to a white object as gray again.
*/
-void luaC_barrierback_ (lua_State *L, GCObject *o) {
+void luaC_barrierback_ (lua_State *L, Table *t) {
global_State *g = G(L);
- lua_assert(isblack(o) && !isdead(g, o) && gch(o)->tt == LUA_TTABLE);
- black2gray(o); /* make object gray (again) */
- gco2t(o)->gclist = g->grayagain;
- g->grayagain = o;
+ lua_assert(isblack(t) && !isdead(g, t));
+ black2gray(t); /* make table gray (again) */
+ linkgclist(t, g->grayagain);
}
/*
-** barrier for prototypes. When creating first closure (cache is
-** NULL), use a forward barrier; this may be the only closure of the
-** prototype (if it is a "regular" function, with a single instance)
-** and the prototype may be big, so it is better to avoid traversing
-** it again. Otherwise, use a backward barrier, to avoid marking all
-** possible instances.
+** barrier for assignments to closed upvalues. Because upvalues are
+** shared among closures, it is impossible to know the color of all
+** closures pointing to it. So, we assume that the object being assigned
+** must be marked.
*/
-LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c) {
+void luaC_upvalbarrier_ (lua_State *L, UpVal *uv) {
global_State *g = G(L);
- lua_assert(isblack(obj2gco(p)));
- if (p->cache == NULL) { /* first time? */
- luaC_objbarrier(L, p, c);
- }
- else { /* use a backward barrier */
- black2gray(obj2gco(p)); /* make prototype gray (again) */
- p->gclist = g->grayagain;
- g->grayagain = obj2gco(p);
- }
+ GCObject *o = gcvalue(uv->v);
+ lua_assert(!upisopen(uv)); /* ensured by macro luaC_upvalbarrier */
+ if (keepinvariant(g))
+ markobject(g, o);
}
-/*
-** check color (and invariants) for an upvalue that was closed,
-** i.e., moved into the 'allgc' list
-*/
-void luaC_checkupvalcolor (global_State *g, UpVal *uv) {
- GCObject *o = obj2gco(uv);
- lua_assert(!isblack(o)); /* open upvalues are never black */
- if (isgray(o)) {
- if (keepinvariant(g)) {
- resetoldbit(o); /* see MOVE OLD rule */
- gray2black(o); /* it is being visited now */
- markvalue(g, uv->v);
- }
- else {
- lua_assert(issweepphase(g));
- makewhite(g, o);
- }
- }
+void luaC_fix (lua_State *L, GCObject *o) {
+ global_State *g = G(L);
+ lua_assert(g->allgc == o); /* object must be 1st in 'allgc' list! */
+ white2gray(o); /* they will be gray forever */
+ g->allgc = o->next; /* remove object from 'allgc' list */
+ o->next = g->fixedgc; /* link it to 'fixedgc' list */
+ g->fixedgc = o;
}
/*
** create a new collectable object (with given type and size) and link
-** it to '*list'. 'offset' tells how many bytes to allocate before the
-** object itself (used only by states).
+** it to 'allgc' list.
*/
-GCObject *luaC_newobj (lua_State *L, int tt, size_t sz, GCObject **list,
- int offset) {
+GCObject *luaC_newobj (lua_State *L, int tt, size_t sz) {
global_State *g = G(L);
- char *raw = cast(char *, luaM_newobject(L, novariant(tt), sz));
- GCObject *o = obj2gco(raw + offset);
- if (list == NULL)
- list = &g->allgc; /* standard list for collectable objects */
- gch(o)->marked = luaC_white(g);
- gch(o)->tt = tt;
- gch(o)->next = *list;
- *list = o;
+ GCObject *o = cast(GCObject *, luaM_newobject(L, novariant(tt), sz));
+ o->marked = luaC_white(g);
+ o->tt = tt;
+ o->next = g->allgc;
+ g->allgc = o;
return o;
}
@@ -241,57 +223,49 @@ GCObject *luaC_newobj (lua_State *L, int tt, size_t sz, GCObject **list,
** upvalues are already linked in 'headuv' list.)
*/
static void reallymarkobject (global_State *g, GCObject *o) {
- lu_mem size;
+ reentry:
white2gray(o);
- switch (gch(o)->tt) {
+ switch (o->tt) {
case LUA_TSHRSTR:
case LUA_TLNGSTR: {
- size = sizestring(gco2ts(o));
- break; /* nothing else to mark; make it black */
- }
- case LUA_TUSERDATA: {
- Table *mt = gco2u(o)->metatable;
- markobject(g, mt);
- markobject(g, gco2u(o)->env);
- size = sizeudata(gco2u(o));
+ gray2black(o);
+ g->GCmemtrav += sizestring(gco2ts(o));
break;
}
- case LUA_TUPVAL: {
- UpVal *uv = gco2uv(o);
- markvalue(g, uv->v);
- if (uv->v != &uv->u.value) /* open? */
- return; /* open upvalues remain gray */
- size = sizeof(UpVal);
+ case LUA_TUSERDATA: {
+ TValue uvalue;
+ markobject(g, gco2u(o)->metatable); /* mark its metatable */
+ gray2black(o);
+ g->GCmemtrav += sizeudata(gco2u(o));
+ getuservalue(g->mainthread, gco2u(o), &uvalue);
+ if (valiswhite(&uvalue)) { /* markvalue(g, &uvalue); */
+ o = gcvalue(&uvalue);
+ goto reentry;
+ }
break;
}
case LUA_TLCL: {
- gco2lcl(o)->gclist = g->gray;
- g->gray = o;
- return;
+ linkgclist(gco2lcl(o), g->gray);
+ break;
}
case LUA_TCCL: {
- gco2ccl(o)->gclist = g->gray;
- g->gray = o;
- return;
+ linkgclist(gco2ccl(o), g->gray);
+ break;
}
case LUA_TTABLE: {
- linktable(gco2t(o), &g->gray);
- return;
+ linkgclist(gco2t(o), g->gray);
+ break;
}
case LUA_TTHREAD: {
- gco2th(o)->gclist = g->gray;
- g->gray = o;
- return;
+ linkgclist(gco2th(o), g->gray);
+ break;
}
case LUA_TPROTO: {
- gco2p(o)->gclist = g->gray;
- g->gray = o;
- return;
+ linkgclist(gco2p(o), g->gray);
+ break;
}
- default: lua_assert(0); return;
+ default: lua_assert(0); break;
}
- gray2black(o);
- g->GCmemtrav += size;
}
@@ -310,29 +284,41 @@ static void markmt (global_State *g) {
*/
static void markbeingfnz (global_State *g) {
GCObject *o;
- for (o = g->tobefnz; o != NULL; o = gch(o)->next) {
- makewhite(g, o);
- reallymarkobject(g, o);
- }
+ for (o = g->tobefnz; o != NULL; o = o->next)
+ markobject(g, o);
}
/*
-** mark all values stored in marked open upvalues. (See comment in
-** 'lstate.h'.)
+** Mark all values stored in marked open upvalues from non-marked threads.
+** (Values from marked threads were already marked when traversing the
+** thread.) Remove from the list threads that no longer have upvalues and
+** not-marked threads.
*/
static void remarkupvals (global_State *g) {
- UpVal *uv;
- for (uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next) {
- if (isgray(obj2gco(uv)))
- markvalue(g, uv->v);
+ lua_State *thread;
+ lua_State **p = &g->twups;
+ while ((thread = *p) != NULL) {
+ lua_assert(!isblack(thread)); /* threads are never black */
+ if (isgray(thread) && thread->openupval != NULL)
+ p = &thread->twups; /* keep marked thread with upvalues in the list */
+ else { /* thread is not marked or without upvalues */
+ UpVal *uv;
+ *p = thread->twups; /* remove thread from the list */
+ thread->twups = thread; /* mark that it is out of list */
+ for (uv = thread->openupval; uv != NULL; uv = uv->u.open.next) {
+ if (uv->u.open.touched) {
+ markvalue(g, uv->v); /* remark upvalue's value */
+ uv->u.open.touched = 0;
+ }
+ }
+ }
}
}
/*
-** mark root set and reset all gray lists, to start a new
-** incremental (or full) collection
+** mark root set and reset all gray lists, to start a new collection
*/
static void restartcollection (global_State *g) {
g->gray = g->grayagain = NULL;
@@ -352,12 +338,18 @@ static void restartcollection (global_State *g) {
** =======================================================
*/
+/*
+** Traverse a table with weak values and link it to proper list. During
+** propagate phase, keep it in 'grayagain' list, to be revisited in the
+** atomic phase. In the atomic phase, if table has any white value,
+** put it in 'weak' list, to be cleared.
+*/
static void traverseweakvalue (global_State *g, Table *h) {
Node *n, *limit = gnodelast(h);
- /* if there is array part, assume it may have white values (do not
- traverse it just to check) */
+ /* if there is array part, assume it may have white values (it is not
+ worth traversing it now just to check) */
int hasclears = (h->sizearray > 0);
- for (n = gnode(h, 0); n < limit; n++) {
+ for (n = gnode(h, 0); n < limit; n++) { /* traverse hash part */
checkdeadkey(n);
if (ttisnil(gval(n))) /* entry is empty? */
removeentry(n); /* remove it */
@@ -368,20 +360,30 @@ static void traverseweakvalue (global_State *g, Table *h) {
hasclears = 1; /* table will have to be cleared */
}
}
- if (hasclears)
- linktable(h, &g->weak); /* has to be cleared later */
- else /* no white values */
- linktable(h, &g->grayagain); /* no need to clean */
+ if (g->gcstate == GCSpropagate)
+ linkgclist(h, g->grayagain); /* must retraverse it in atomic phase */
+ else if (hasclears)
+ linkgclist(h, g->weak); /* has to be cleared later */
}
+/*
+** Traverse an ephemeron table and link it to proper list. Returns true
+** iff any object was marked during this traversal (which implies that
+** convergence has to continue). During propagation phase, keep table
+** in 'grayagain' list, to be visited again in the atomic phase. In
+** the atomic phase, if table has any white->white entry, it has to
+** be revisited during ephemeron convergence (as that key may turn
+** black). Otherwise, if it has any white key, table has to be cleared
+** (in the atomic phase).
+*/
static int traverseephemeron (global_State *g, Table *h) {
int marked = 0; /* true if an object is marked in this traversal */
int hasclears = 0; /* true if table has white keys */
- int prop = 0; /* true if table has entry "white-key -> white-value" */
+ int hasww = 0; /* true if table has entry "white-key -> white-value" */
Node *n, *limit = gnodelast(h);
- int i;
- /* traverse array part (numeric keys are 'strong') */
+ unsigned int i;
+ /* traverse array part */
for (i = 0; i < h->sizearray; i++) {
if (valiswhite(&h->array[i])) {
marked = 1;
@@ -396,26 +398,27 @@ static int traverseephemeron (global_State *g, Table *h) {
else if (iscleared(g, gkey(n))) { /* key is not marked (yet)? */
hasclears = 1; /* table must be cleared */
if (valiswhite(gval(n))) /* value not marked yet? */
- prop = 1; /* must propagate again */
+ hasww = 1; /* white-white entry */
}
else if (valiswhite(gval(n))) { /* value not marked yet? */
marked = 1;
reallymarkobject(g, gcvalue(gval(n))); /* mark it now */
}
}
- if (prop)
- linktable(h, &g->ephemeron); /* have to propagate again */
- else if (hasclears) /* does table have white keys? */
- linktable(h, &g->allweak); /* may have to clean white keys */
- else /* no white keys */
- linktable(h, &g->grayagain); /* no need to clean */
+ /* link table into proper list */
+ if (g->gcstate == GCSpropagate)
+ linkgclist(h, g->grayagain); /* must retraverse it in atomic phase */
+ else if (hasww) /* table has white->white entries? */
+ linkgclist(h, g->ephemeron); /* have to propagate again */
+ else if (hasclears) /* table has white keys? */
+ linkgclist(h, g->allweak); /* may have to clean white keys */
return marked;
}
static void traversestrongtable (global_State *g, Table *h) {
Node *n, *limit = gnodelast(h);
- int i;
+ unsigned int i;
for (i = 0; i < h->sizearray; i++) /* traverse array part */
markvalue(g, &h->array[i]);
for (n = gnode(h, 0); n < limit; n++) { /* traverse hash part */
@@ -439,13 +442,13 @@ static lu_mem traversetable (global_State *g, Table *h) {
((weakkey = strchr(svalue(mode), 'k')),
(weakvalue = strchr(svalue(mode), 'v')),
(weakkey || weakvalue))) { /* is really weak? */
- black2gray(obj2gco(h)); /* keep table gray */
+ black2gray(h); /* keep table gray */
if (!weakkey) /* strong keys? */
traverseweakvalue(g, h);
else if (!weakvalue) /* strong values? */
traverseephemeron(g, h);
else /* all weak */
- linktable(h, &g->allweak); /* nothing to traverse now */
+ linkgclist(h, g->allweak); /* nothing to traverse now */
}
else /* not weak */
traversestrongtable(g, h);
@@ -456,7 +459,7 @@ static lu_mem traversetable (global_State *g, Table *h) {
static int traverseproto (global_State *g, Proto *f) {
int i;
- if (f->cache && iswhite(obj2gco(f->cache)))
+ if (f->cache && iswhite(f->cache))
f->cache = NULL; /* allow cache to be collected */
markobject(g, f->source);
for (i = 0; i < f->sizek; i++) /* mark literals */
@@ -483,34 +486,49 @@ static lu_mem traverseCclosure (global_State *g, CClosure *cl) {
return sizeCclosure(cl->nupvalues);
}
+/*
+** open upvalues point to values in a thread, so those values should
+** be marked when the thread is traversed except in the atomic phase
+** (because then the value cannot be changed by the thread and the
+** thread may not be traversed again)
+*/
static lu_mem traverseLclosure (global_State *g, LClosure *cl) {
int i;
markobject(g, cl->p); /* mark its prototype */
- for (i = 0; i < cl->nupvalues; i++) /* mark its upvalues */
- markobject(g, cl->upvals[i]);
+ for (i = 0; i < cl->nupvalues; i++) { /* mark its upvalues */
+ UpVal *uv = cl->upvals[i];
+ if (uv != NULL) {
+ if (upisopen(uv) && g->gcstate != GCSinsideatomic)
+ uv->u.open.touched = 1; /* can be marked in 'remarkupvals' */
+ else
+ markvalue(g, uv->v);
+ }
+ }
return sizeLclosure(cl->nupvalues);
}
-static lu_mem traversestack (global_State *g, lua_State *th) {
- int n = 0;
+static lu_mem traversethread (global_State *g, lua_State *th) {
StkId o = th->stack;
if (o == NULL)
return 1; /* stack not completely built yet */
+ lua_assert(g->gcstate == GCSinsideatomic ||
+ th->openupval == NULL || isintwups(th));
for (; o < th->top; o++) /* mark live elements in the stack */
markvalue(g, o);
- if (g->gcstate == GCSatomic) { /* final traversal? */
+ if (g->gcstate == GCSinsideatomic) { /* final traversal? */
StkId lim = th->stack + th->stacksize; /* real end of stack */
for (; o < lim; o++) /* clear not-marked stack slice */
setnilvalue(o);
+ /* 'remarkupvals' may have removed thread from 'twups' list */
+ if (!isintwups(th) && th->openupval != NULL) {
+ th->twups = g->twups; /* link it back to the list */
+ g->twups = th;
+ }
}
- else { /* count call infos to compute size */
- CallInfo *ci;
- for (ci = &th->base_ci; ci != th->ci; ci = ci->next)
- n++;
- }
- return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
- sizeof(CallInfo) * n;
+ else if (g->gckind != KGC_EMERGENCY)
+ luaD_shrinkstack(th); /* do not change stack in emergency cycle */
+ return (sizeof(lua_State) + sizeof(TValue) * th->stacksize);
}
@@ -523,7 +541,7 @@ static void propagatemark (global_State *g) {
GCObject *o = g->gray;
lua_assert(isgray(o));
gray2black(o);
- switch (gch(o)->tt) {
+ switch (o->tt) {
case LUA_TTABLE: {
Table *h = gco2t(o);
g->gray = h->gclist; /* remove from 'gray' list */
@@ -545,10 +563,9 @@ static void propagatemark (global_State *g) {
case LUA_TTHREAD: {
lua_State *th = gco2th(o);
g->gray = th->gclist; /* remove from 'gray' list */
- th->gclist = g->grayagain;
- g->grayagain = o; /* insert into 'grayagain' list */
+ linkgclist(th, g->grayagain); /* insert into 'grayagain' list */
black2gray(o);
- size = traversestack(g, th);
+ size = traversethread(g, th);
break;
}
case LUA_TPROTO: {
@@ -568,35 +585,12 @@ static void propagateall (global_State *g) {
}
-static void propagatelist (global_State *g, GCObject *l) {
- lua_assert(g->gray == NULL); /* no grays left */
- g->gray = l;
- propagateall(g); /* traverse all elements from 'l' */
-}
-
-/*
-** retraverse all gray lists. Because tables may be reinserted in other
-** lists when traversed, traverse the original lists to avoid traversing
-** twice the same table (which is not wrong, but inefficient)
-*/
-static void retraversegrays (global_State *g) {
- GCObject *weak = g->weak; /* save original lists */
- GCObject *grayagain = g->grayagain;
- GCObject *ephemeron = g->ephemeron;
- g->weak = g->grayagain = g->ephemeron = NULL;
- propagateall(g); /* traverse main gray list */
- propagatelist(g, grayagain);
- propagatelist(g, weak);
- propagatelist(g, ephemeron);
-}
-
-
static void convergeephemerons (global_State *g) {
int changed;
do {
GCObject *w;
GCObject *next = g->ephemeron; /* get ephemeron list */
- g->ephemeron = NULL; /* tables will return to this list when traversed */
+ g->ephemeron = NULL; /* tables may return to this list when traversed */
changed = 0;
while ((w = next) != NULL) {
next = gco2t(w)->gclist;
@@ -644,7 +638,7 @@ static void clearvalues (global_State *g, GCObject *l, GCObject *f) {
for (; l != f; l = gco2t(l)->gclist) {
Table *h = gco2t(l);
Node *n, *limit = gnodelast(h);
- int i;
+ unsigned int i;
for (i = 0; i < h->sizearray; i++) {
TValue *o = &h->array[i];
if (iscleared(g, o)) /* value was collected? */
@@ -660,23 +654,41 @@ static void clearvalues (global_State *g, GCObject *l, GCObject *f) {
}
+void luaC_upvdeccount (lua_State *L, UpVal *uv) {
+ lua_assert(uv->refcount > 0);
+ uv->refcount--;
+ if (uv->refcount == 0 && !upisopen(uv))
+ luaM_free(L, uv);
+}
+
+
+static void freeLclosure (lua_State *L, LClosure *cl) {
+ int i;
+ for (i = 0; i < cl->nupvalues; i++) {
+ UpVal *uv = cl->upvals[i];
+ if (uv)
+ luaC_upvdeccount(L, uv);
+ }
+ luaM_freemem(L, cl, sizeLclosure(cl->nupvalues));
+}
+
+
static void freeobj (lua_State *L, GCObject *o) {
- switch (gch(o)->tt) {
+ switch (o->tt) {
case LUA_TPROTO: luaF_freeproto(L, gco2p(o)); break;
case LUA_TLCL: {
- luaM_freemem(L, o, sizeLclosure(gco2lcl(o)->nupvalues));
+ freeLclosure(L, gco2lcl(o));
break;
}
case LUA_TCCL: {
luaM_freemem(L, o, sizeCclosure(gco2ccl(o)->nupvalues));
break;
}
- case LUA_TUPVAL: luaF_freeupval(L, gco2uv(o)); break;
case LUA_TTABLE: luaH_free(L, gco2t(o)); break;
case LUA_TTHREAD: luaE_freethread(L, gco2th(o)); break;
case LUA_TUSERDATA: luaM_freemem(L, o, sizeudata(gco2u(o))); break;
case LUA_TSHRSTR:
- G(L)->strt.nuse--;
+ luaS_remove(L, gco2ts(o)); /* remove it from hash table */
/* go through */
case LUA_TLNGSTR: {
luaM_freemem(L, o, sizestring(gco2ts(o)));
@@ -692,60 +704,26 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count);
/*
-** sweep the (open) upvalues of a thread and resize its stack and
-** list of call-info structures.
-*/
-static void sweepthread (lua_State *L, lua_State *L1) {
- if (L1->stack == NULL) return; /* stack not completely built yet */
- sweepwholelist(L, &L1->openupval); /* sweep open upvalues */
- luaE_freeCI(L1); /* free extra CallInfo slots */
- /* should not change the stack during an emergency gc cycle */
- if (G(L)->gckind != KGC_EMERGENCY)
- luaD_shrinkstack(L1);
-}
-
-
-/*
** sweep at most 'count' elements from a list of GCObjects erasing dead
-** objects, where a dead (not alive) object is one marked with the "old"
-** (non current) white and not fixed.
-** In non-generational mode, change all non-dead objects back to white,
-** preparing for next collection cycle.
-** In generational mode, keep black objects black, and also mark them as
-** old; stop when hitting an old object, as all objects after that
-** one will be old too.
-** When object is a thread, sweep its list of open upvalues too.
+** objects, where a dead object is one marked with the old (non current)
+** white; change all non-dead objects back to white, preparing for next
+** collection cycle. Return where to continue the traversal or NULL if
+** list is finished.
*/
static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
global_State *g = G(L);
int ow = otherwhite(g);
- int toclear, toset; /* bits to clear and to set in all live objects */
- int tostop; /* stop sweep when this is true */
- if (isgenerational(g)) { /* generational mode? */
- toclear = ~0; /* clear nothing */
- toset = bitmask(OLDBIT); /* set the old bit of all surviving objects */
- tostop = bitmask(OLDBIT); /* do not sweep old generation */
- }
- else { /* normal mode */
- toclear = maskcolors; /* clear all color bits + old bit */
- toset = luaC_white(g); /* make object white */
- tostop = 0; /* do not stop */
- }
+ int white = luaC_white(g); /* current white */
while (*p != NULL && count-- > 0) {
GCObject *curr = *p;
- int marked = gch(curr)->marked;
+ int marked = curr->marked;
if (isdeadm(ow, marked)) { /* is 'curr' dead? */
- *p = gch(curr)->next; /* remove 'curr' from list */
+ *p = curr->next; /* remove 'curr' from list */
freeobj(L, curr); /* erase 'curr' */
}
- else {
- if (testbits(marked, tostop))
- return NULL; /* stop sweeping this list */
- if (gch(curr)->tt == LUA_TTHREAD)
- sweepthread(L, gco2th(curr)); /* sweep thread's upvalues */
- /* update marks */
- gch(curr)->marked = cast_byte((marked & toclear) | toset);
- p = &gch(curr)->next; /* go to next element */
+ else { /* change mark to 'white' */
+ curr->marked = cast_byte((marked & maskcolors) | white);
+ p = &curr->next; /* go to next element */
}
}
return (*p == NULL) ? NULL : p;
@@ -756,7 +734,7 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
** sweep a list until a live object (or end of list)
*/
static GCObject **sweeptolive (lua_State *L, GCObject **p, int *n) {
- GCObject ** old = p;
+ GCObject **old = p;
int i = 0;
do {
i++;
@@ -775,26 +753,28 @@ static GCObject **sweeptolive (lua_State *L, GCObject **p, int *n) {
** =======================================================
*/
-static void checkSizes (lua_State *L) {
- global_State *g = G(L);
- if (g->gckind != KGC_EMERGENCY) { /* do not change sizes in emergency */
- int hs = g->strt.size / 2; /* half the size of the string table */
- if (g->strt.nuse < cast(lu_int32, hs)) /* using less than that half? */
- luaS_resize(L, hs); /* halve its size */
+/*
+** If possible, free concatenation buffer and shrink string table
+*/
+static void checkSizes (lua_State *L, global_State *g) {
+ if (g->gckind != KGC_EMERGENCY) {
+ l_mem olddebt = g->GCdebt;
luaZ_freebuffer(L, &g->buff); /* free concatenation buffer */
+ if (g->strt.nuse < g->strt.size / 4) /* string table too big? */
+ luaS_resize(L, g->strt.size / 2); /* shrink it a little */
+ g->GCestimate += g->GCdebt - olddebt; /* update estimate */
}
}
static GCObject *udata2finalize (global_State *g) {
GCObject *o = g->tobefnz; /* get first element */
- lua_assert(isfinalized(o));
- g->tobefnz = gch(o)->next; /* remove it from 'tobefnz' list */
- gch(o)->next = g->allgc; /* return it to 'allgc' list */
+ lua_assert(tofinalize(o));
+ g->tobefnz = o->next; /* remove it from 'tobefnz' list */
+ o->next = g->allgc; /* return it to 'allgc' list */
g->allgc = o;
- resetbit(gch(o)->marked, SEPARATED); /* mark that it is not in 'tobefnz' */
- lua_assert(!isold(o)); /* see MOVE OLD rule */
- if (!keepinvariantout(g)) /* not keeping invariant? */
+ resetbit(o->marked, FINALIZEDBIT); /* object is "normal" again */
+ if (issweepphase(g))
makewhite(g, o); /* "sweep" object */
return o;
}
@@ -839,28 +819,57 @@ static void GCTM (lua_State *L, int propagateerrors) {
/*
+** call a few (up to 'g->gcfinnum') finalizers
+*/
+static int runafewfinalizers (lua_State *L) {
+ global_State *g = G(L);
+ unsigned int i;
+ lua_assert(!g->tobefnz || g->gcfinnum > 0);
+ for (i = 0; g->tobefnz && i < g->gcfinnum; i++)
+ GCTM(L, 1); /* call one finalizer */
+ g->gcfinnum = (!g->tobefnz) ? 0 /* nothing more to finalize? */
+ : g->gcfinnum * 2; /* else call a few more next time */
+ return i;
+}
+
+
+/*
+** call all pending finalizers
+*/
+static void callallpendingfinalizers (lua_State *L, int propagateerrors) {
+ global_State *g = G(L);
+ while (g->tobefnz)
+ GCTM(L, propagateerrors);
+}
+
+
+/*
+** find last 'next' field in list 'p' list (to add elements in its end)
+*/
+static GCObject **findlast (GCObject **p) {
+ while (*p != NULL)
+ p = &(*p)->next;
+ return p;
+}
+
+
+/*
** move all unreachable objects (or 'all' objects) that need
** finalization from list 'finobj' to list 'tobefnz' (to be finalized)
*/
-static void separatetobefnz (lua_State *L, int all) {
- global_State *g = G(L);
- GCObject **p = &g->finobj;
+static void separatetobefnz (global_State *g, int all) {
GCObject *curr;
- GCObject **lastnext = &g->tobefnz;
- /* find last 'next' field in 'tobefnz' list (to add elements in its end) */
- while (*lastnext != NULL)
- lastnext = &gch(*lastnext)->next;
+ GCObject **p = &g->finobj;
+ GCObject **lastnext = findlast(&g->tobefnz);
while ((curr = *p) != NULL) { /* traverse all finalizable objects */
- lua_assert(!isfinalized(curr));
- lua_assert(testbit(gch(curr)->marked, SEPARATED));
+ lua_assert(tofinalize(curr));
if (!(iswhite(curr) || all)) /* not being collected? */
- p = &gch(curr)->next; /* don't bother with it */
+ p = &curr->next; /* don't bother with it */
else {
- l_setbit(gch(curr)->marked, FINALIZEDBIT); /* won't be finalized again */
- *p = gch(curr)->next; /* remove 'curr' from 'finobj' list */
- gch(curr)->next = *lastnext; /* link at the end of 'tobefnz' list */
+ *p = curr->next; /* remove 'curr' from 'finobj' list */
+ curr->next = *lastnext; /* link at the end of 'tobefnz' list */
*lastnext = curr;
- lastnext = &gch(curr)->next;
+ lastnext = &curr->next;
}
}
}
@@ -872,33 +881,29 @@ static void separatetobefnz (lua_State *L, int all) {
*/
void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
global_State *g = G(L);
- if (testbit(gch(o)->marked, SEPARATED) || /* obj. is already separated... */
- isfinalized(o) || /* ... or is finalized... */
- gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
+ if (tofinalize(o) || /* obj. is already marked... */
+ gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
return; /* nothing to be done */
else { /* move 'o' to 'finobj' list */
GCObject **p;
- GCheader *ho = gch(o);
- if (g->sweepgc == &ho->next) { /* avoid removing current sweep object */
- lua_assert(issweepphase(g));
- g->sweepgc = sweeptolive(L, g->sweepgc, NULL);
+ if (issweepphase(g)) {
+ makewhite(g, o); /* "sweep" object 'o' */
+ if (g->sweepgc == &o->next) /* should not remove 'sweepgc' object */
+ g->sweepgc = sweeptolive(L, g->sweepgc, NULL); /* change 'sweepgc' */
}
/* search for pointer pointing to 'o' */
- for (p = &g->allgc; *p != o; p = &gch(*p)->next) { /* empty */ }
- *p = ho->next; /* remove 'o' from root list */
- ho->next = g->finobj; /* link it in list 'finobj' */
+ for (p = &g->allgc; *p != o; p = &(*p)->next) { /* empty */ }
+ *p = o->next; /* remove 'o' from 'allgc' list */
+ o->next = g->finobj; /* link it in 'finobj' list */
g->finobj = o;
- l_setbit(ho->marked, SEPARATED); /* mark it as such */
- if (!keepinvariantout(g)) /* not keeping invariant? */
- makewhite(g, o); /* "sweep" object */
- else
- resetoldbit(o); /* see MOVE OLD rule */
+ l_setbit(o->marked, FINALIZEDBIT); /* mark it as such */
}
}
/* }====================================================== */
+
/*
** {======================================================
** GC control
@@ -907,127 +912,93 @@ 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
+** Set a reasonable "time" to wait before starting a new GC cycle; cycle
+** will start when memory use hits threshold. (Division by 'estimate'
+** should be OK: it cannot be zero (because Lua cannot even start with
+** less than PAUSEADJ bytes).
*/
-static void setpause (global_State *g, l_mem estimate) {
- l_mem debt, threshold;
- estimate = estimate / PAUSEADJ; /* adjust 'estimate' */
+static void setpause (global_State *g) {
+ l_mem threshold, debt;
+ l_mem estimate = g->GCestimate / PAUSEADJ; /* adjust 'estimate' */
+ lua_assert(estimate > 0);
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));
+ debt = gettotalbytes(g) - threshold;
luaE_setdebt(g, debt);
}
-#define sweepphases \
- (bitmask(GCSsweepstring) | bitmask(GCSsweepudata) | bitmask(GCSsweep))
-
-
/*
-** enter first sweep phase (strings) and prepare pointers for other
-** sweep phases. The calls to 'sweeptolive' make pointers point to an
-** object inside the list (instead of to the header), so that the real
-** sweep do not need to skip objects created between "now" and the start
-** of the real sweep.
+** Enter first sweep phase.
+** The call to 'sweeptolive' makes pointer point to an object inside
+** the list (instead of to the header), so that the real sweep do not
+** need to skip objects created between "now" and the start of the real
+** sweep.
** Returns how many objects it swept.
*/
static int entersweep (lua_State *L) {
global_State *g = G(L);
int n = 0;
- g->gcstate = GCSsweepstring;
- lua_assert(g->sweepgc == NULL && g->sweepfin == NULL);
- /* prepare to sweep strings, finalizable objects, and regular objects */
- g->sweepstrgc = 0;
- g->sweepfin = sweeptolive(L, &g->finobj, &n);
+ g->gcstate = GCSswpallgc;
+ lua_assert(g->sweepgc == NULL);
g->sweepgc = sweeptolive(L, &g->allgc, &n);
return n;
}
-/*
-** 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);
- }
-}
-
-
-/*
-** call all pending finalizers
-*/
-static void callallpendingfinalizers (lua_State *L, int propagateerrors) {
- global_State *g = G(L);
- while (g->tobefnz) {
- resetoldbit(g->tobefnz);
- GCTM(L, propagateerrors);
- }
-}
-
-
void luaC_freeallobjects (lua_State *L) {
global_State *g = G(L);
- int i;
- separatetobefnz(L, 1); /* separate all objects with finalizers */
+ separatetobefnz(g, 1); /* separate all objects with finalizers */
lua_assert(g->finobj == NULL);
callallpendingfinalizers(L, 0);
+ lua_assert(g->tobefnz == NULL);
g->currentwhite = WHITEBITS; /* this "white" makes all objects look dead */
g->gckind = KGC_NORMAL;
- sweepwholelist(L, &g->finobj); /* finalizers can create objs. in 'finobj' */
+ sweepwholelist(L, &g->finobj);
sweepwholelist(L, &g->allgc);
- for (i = 0; i < g->strt.size; i++) /* free all string lists */
- sweepwholelist(L, &g->strt.hash[i]);
+ sweepwholelist(L, &g->fixedgc); /* collect fixed objects */
lua_assert(g->strt.nuse == 0);
}
static l_mem atomic (lua_State *L) {
global_State *g = G(L);
- l_mem work = -cast(l_mem, g->GCmemtrav); /* start counting work */
+ l_mem work;
GCObject *origweak, *origall;
- lua_assert(!iswhite(obj2gco(g->mainthread)));
+ GCObject *grayagain = g->grayagain; /* save original list */
+ lua_assert(g->ephemeron == NULL && g->weak == NULL);
+ lua_assert(!iswhite(g->mainthread));
+ g->gcstate = GCSinsideatomic;
+ g->GCmemtrav = 0; /* start counting work */
markobject(g, L); /* mark running thread */
/* registry and global metatables may be changed by API */
markvalue(g, &g->l_registry);
- markmt(g); /* mark basic metatables */
+ markmt(g); /* mark global metatables */
/* remark occasional upvalues of (maybe) dead threads */
remarkupvals(g);
propagateall(g); /* propagate changes */
- work += g->GCmemtrav; /* stop counting (do not (re)count grays) */
- /* traverse objects caught by write barrier and by 'remarkupvals' */
- retraversegrays(g);
- work -= g->GCmemtrav; /* restart counting */
+ work = g->GCmemtrav; /* stop counting (do not recount 'grayagain') */
+ g->gray = grayagain;
+ propagateall(g); /* traverse 'grayagain' list */
+ g->GCmemtrav = 0; /* restart counting */
convergeephemerons(g);
/* at this point, all strongly accessible objects are marked. */
- /* clear values from weak tables, before checking finalizers */
+ /* Clear values from weak tables, before checking finalizers */
clearvalues(g, g->weak, NULL);
clearvalues(g, g->allweak, NULL);
origweak = g->weak; origall = g->allweak;
work += g->GCmemtrav; /* stop counting (objects being finalized) */
- separatetobefnz(L, 0); /* separate objects to be finalized */
+ separatetobefnz(g, 0); /* separate objects to be finalized */
+ g->gcfinnum = 1; /* there may be objects to be finalized */
markbeingfnz(g); /* mark objects that will be finalized */
- propagateall(g); /* remark, to propagate `preserveness' */
- work -= g->GCmemtrav; /* restart counting */
+ propagateall(g); /* remark, to propagate 'resurrection' */
+ g->GCmemtrav = 0; /* restart counting */
convergeephemerons(g);
/* at this point, all resurrected objects are marked. */
/* remove dead objects from weak tables */
clearkeys(g, g->ephemeron, NULL); /* clear keys from all ephemeron tables */
- clearkeys(g, g->allweak, NULL); /* clear keys from all allweak tables */
+ clearkeys(g, g->allweak, NULL); /* clear keys from all 'allweak' tables */
/* clear values from resurrected weak tables */
clearvalues(g, g->weak, origweak);
clearvalues(g, g->allweak, origall);
@@ -1037,65 +1008,71 @@ static l_mem atomic (lua_State *L) {
}
+static lu_mem sweepstep (lua_State *L, global_State *g,
+ int nextstate, GCObject **nextlist) {
+ if (g->sweepgc) {
+ l_mem olddebt = g->GCdebt;
+ g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
+ g->GCestimate += g->GCdebt - olddebt; /* update estimate */
+ if (g->sweepgc) /* is there still something to sweep? */
+ return (GCSWEEPMAX * GCSWEEPCOST);
+ }
+ /* else enter next state */
+ g->gcstate = nextstate;
+ g->sweepgc = nextlist;
+ return 0;
+}
+
+
static lu_mem singlestep (lua_State *L) {
global_State *g = G(L);
switch (g->gcstate) {
case GCSpause: {
- /* start to count memory traversed */
g->GCmemtrav = g->strt.size * sizeof(GCObject*);
- lua_assert(!isgenerational(g));
restartcollection(g);
g->gcstate = GCSpropagate;
return g->GCmemtrav;
}
case GCSpropagate: {
- if (g->gray) {
- lu_mem oldtrav = g->GCmemtrav;
- propagatemark(g);
- return g->GCmemtrav - oldtrav; /* memory traversed in this step */
- }
- else { /* no more `gray' objects */
- lu_mem work;
- int sw;
- g->gcstate = GCSatomic; /* finish mark phase */
- g->GCestimate = g->GCmemtrav; /* save what was counted */;
- work = atomic(L); /* add what was traversed by 'atomic' */
- g->GCestimate += work; /* estimate of total memory traversed */
- sw = entersweep(L);
- return work + sw * GCSWEEPCOST;
- }
+ 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 GCSsweepstring: {
- int i;
- for (i = 0; i < GCSWEEPMAX && g->sweepstrgc + i < g->strt.size; i++)
- sweepwholelist(L, &g->strt.hash[g->sweepstrgc + i]);
- g->sweepstrgc += i;
- if (g->sweepstrgc >= g->strt.size) /* no more strings to sweep? */
- g->gcstate = GCSsweepudata;
- return i * GCSWEEPCOST;
+ 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 GCSsweepudata: {
- if (g->sweepfin) {
- g->sweepfin = sweeplist(L, g->sweepfin, GCSWEEPMAX);
- return GCSWEEPMAX*GCSWEEPCOST;
- }
- else {
- g->gcstate = GCSsweep;
- return 0;
- }
+ 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 GCSsweep: {
- if (g->sweepgc) {
- g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
- return GCSWEEPMAX*GCSWEEPCOST;
+ 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 {
- /* sweep main thread */
- GCObject *mt = obj2gco(g->mainthread);
- sweeplist(L, &mt, 1);
- checkSizes(L);
+ else { /* emergency mode or no more finalizers */
g->gcstate = GCSpause; /* finish collection */
- return GCSWEEPCOST;
+ return 0;
}
}
default: lua_assert(0); return 0;
@@ -1114,105 +1091,67 @@ void luaC_runtilstate (lua_State *L, int statesmask) {
}
-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 incstep (lua_State *L) {
- global_State *g = G(L);
+/*
+** get GC debt and convert it from Kb to 'work units' (avoid zero debt
+** and overflows)
+*/
+static l_mem getdebt (global_State *g) {
l_mem debt = g->GCdebt;
int stepmul = g->gcstepmul;
- 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;
- do { /* always perform at least one single step */
- lu_mem work = singlestep(L); /* do some work */
- debt -= work;
- } while (debt > -GCSTEPSIZE && g->gcstate != GCSpause);
- if (g->gcstate == GCSpause)
- setpause(g, g->GCestimate); /* pause until next cycle */
- else {
- debt = (debt / stepmul) * STEPMULADJ; /* convert 'work units' to Kb */
- luaE_setdebt(g, debt);
- }
+ return debt;
}
-
/*
-** performs a basic GC step
-*/
-void luaC_forcestep (lua_State *L) {
- global_State *g = G(L);
- int i;
- if (isgenerational(g)) generationalcollection(L);
- else incstep(L);
- /* run a few finalizers (or all of them at the end of a collect cycle) */
- for (i = 0; g->tobefnz && (i < GCFINALIZENUM || g->gcstate == GCSpause); i++)
- GCTM(L, 1); /* call one finalizer */
-}
-
-
-/*
-** performs a basic GC step only if collector is running
+** performs a basic GC step when collector is running
*/
void luaC_step (lua_State *L) {
global_State *g = G(L);
- if (g->gcrunning) luaC_forcestep(L);
- else luaE_setdebt(g, -GCSTEPSIZE); /* avoid being called too often */
+ l_mem debt = getdebt(g); /* GC deficit (be paid now) */
+ if (!g->gcrunning) { /* not running? */
+ luaE_setdebt(g, -GCSTEPSIZE * 10); /* avoid being called too often */
+ return;
+ }
+ do { /* repeat until pause or enough "credit" (negative debt) */
+ lu_mem work = singlestep(L); /* perform one single step */
+ debt -= work;
+ } while (debt > -GCSTEPSIZE && g->gcstate != GCSpause);
+ if (g->gcstate == GCSpause)
+ setpause(g); /* pause until next cycle */
+ else {
+ debt = (debt / g->gcstepmul) * STEPMULADJ; /* convert 'work units' to Kb */
+ luaE_setdebt(g, debt);
+ runafewfinalizers(L);
+ }
}
-
/*
-** performs a full GC cycle; if "isemergency", does not call
-** finalizers (which could change stack positions)
+** 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);
- 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);
+ 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(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);
+ 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);
}
/* }====================================================== */