]>
git.proxmox.com Git - ceph.git/blob - ceph/src/jaegertracing/opentelemetry-cpp/third_party/prometheus-cpp/3rdparty/civetweb/src/third_party/lua-5.3.6/src/lgc.c
2 ** $Id: lgc.c,v 2.215.1.2 2017/08/31 16:15:27 roberto Exp $
4 ** See Copyright Notice in lua.h
30 ** internal state for collector while inside the atomic phase. The
31 ** collector should never be in this state while running regular code.
33 #define GCSinsideatomic (GCSpause + 1)
36 ** cost of sweeping one element (the size of a small object divided
37 ** by some adjust for the sweep speed)
39 #define GCSWEEPCOST ((sizeof(TString) + 4) / 4)
41 /* maximum number of elements to sweep in each single step */
42 #define GCSWEEPMAX (cast_int((GCSTEPSIZE / GCSWEEPCOST) / 4))
44 /* cost of calling one finalizer */
45 #define GCFINALIZECOST GCSWEEPCOST
49 ** macro to adjust 'stepmul': 'stepmul' is actually used like
50 ** 'stepmul / STEPMULADJ' (value chosen by tests)
52 #define STEPMULADJ 200
56 ** macro to adjust 'pause': 'pause' is actually used like
57 ** 'pause / PAUSEADJ' (value chosen by tests)
63 ** 'makewhite' erases all color bits then sets only the current white
66 #define maskcolors (~(bitmask(BLACKBIT) | WHITEBITS))
67 #define makewhite(g,x) \
68 (x->marked = cast_byte((x->marked & maskcolors) | luaC_white(g)))
70 #define white2gray(x) resetbits(x->marked, WHITEBITS)
71 #define black2gray(x) resetbit(x->marked, BLACKBIT)
74 #define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x)))
76 #define checkdeadkey(n) lua_assert(!ttisdeadkey(gkey(n)) || ttisnil(gval(n)))
79 #define checkconsistency(obj) \
80 lua_longassert(!iscollectable(obj) || righttt(obj))
83 #define markvalue(g,o) { checkconsistency(o); \
84 if (valiswhite(o)) reallymarkobject(g,gcvalue(o)); }
86 #define markobject(g,t) { if (iswhite(t)) reallymarkobject(g, obj2gco(t)); }
89 ** mark an object that can be NULL (either because it is really optional,
90 ** or it was stripped as debug info, or inside an uncompleted structure)
92 #define markobjectN(g,t) { if (t) markobject(g,t); }
94 static void reallymarkobject (global_State
*g
, GCObject
*o
);
98 ** {======================================================
100 ** =======================================================
105 ** one after last element in a hash array
107 #define gnodelast(h) gnode(h, cast(size_t, sizenode(h)))
111 ** link collectable object 'o' into list pointed by 'p'
113 #define linkgclist(o,p) ((o)->gclist = (p), (p) = obj2gco(o))
117 ** If key is not marked, mark its entry as dead. This allows key to be
118 ** collected, but keeps its entry in the table. A dead node is needed
119 ** when Lua looks up for a key (it may be part of a chain) and when
120 ** traversing a weak table (key might be removed from the table during
121 ** traversal). Other places never manipulate dead keys, because its
122 ** associated nil value is enough to signal that the entry is logically
125 static void removeentry (Node
*n
) {
126 lua_assert(ttisnil(gval(n
)));
127 if (valiswhite(gkey(n
)))
128 setdeadvalue(wgkey(n
)); /* unused and unmarked key; remove it */
133 ** tells whether a key or value can be cleared from a weak
134 ** table. Non-collectable objects are never removed from weak
135 ** tables. Strings behave as 'values', so are never removed too. for
136 ** other objects: if really collected, cannot keep them; for objects
137 ** being finalized, keep them in keys, but not in values
139 static int iscleared (global_State
*g
, const TValue
*o
) {
140 if (!iscollectable(o
)) return 0;
141 else if (ttisstring(o
)) {
142 markobject(g
, tsvalue(o
)); /* strings are 'values', so are never weak */
145 else return iswhite(gcvalue(o
));
150 ** barrier that moves collector forward, that is, mark the white object
151 ** being pointed by a black object. (If in sweep phase, clear the black
152 ** object to white [sweep it] to avoid other barrier calls for this
155 void luaC_barrier_ (lua_State
*L
, GCObject
*o
, GCObject
*v
) {
156 global_State
*g
= G(L
);
157 lua_assert(isblack(o
) && iswhite(v
) && !isdead(g
, v
) && !isdead(g
, o
));
158 if (keepinvariant(g
)) /* must keep invariant? */
159 reallymarkobject(g
, v
); /* restore invariant */
160 else { /* sweep phase */
161 lua_assert(issweepphase(g
));
162 makewhite(g
, o
); /* mark main obj. as white to avoid other barriers */
168 ** barrier that moves collector backward, that is, mark the black object
169 ** pointing to a white object as gray again.
171 void luaC_barrierback_ (lua_State
*L
, Table
*t
) {
172 global_State
*g
= G(L
);
173 lua_assert(isblack(t
) && !isdead(g
, t
));
174 black2gray(t
); /* make table gray (again) */
175 linkgclist(t
, g
->grayagain
);
180 ** barrier for assignments to closed upvalues. Because upvalues are
181 ** shared among closures, it is impossible to know the color of all
182 ** closures pointing to it. So, we assume that the object being assigned
185 void luaC_upvalbarrier_ (lua_State
*L
, UpVal
*uv
) {
186 global_State
*g
= G(L
);
187 GCObject
*o
= gcvalue(uv
->v
);
188 lua_assert(!upisopen(uv
)); /* ensured by macro luaC_upvalbarrier */
189 if (keepinvariant(g
))
194 void luaC_fix (lua_State
*L
, GCObject
*o
) {
195 global_State
*g
= G(L
);
196 lua_assert(g
->allgc
== o
); /* object must be 1st in 'allgc' list! */
197 white2gray(o
); /* they will be gray forever */
198 g
->allgc
= o
->next
; /* remove object from 'allgc' list */
199 o
->next
= g
->fixedgc
; /* link it to 'fixedgc' list */
205 ** create a new collectable object (with given type and size) and link
206 ** it to 'allgc' list.
208 GCObject
*luaC_newobj (lua_State
*L
, int tt
, size_t sz
) {
209 global_State
*g
= G(L
);
210 GCObject
*o
= cast(GCObject
*, luaM_newobject(L
, novariant(tt
), sz
));
211 o
->marked
= luaC_white(g
);
218 /* }====================================================== */
223 ** {======================================================
225 ** =======================================================
230 ** mark an object. Userdata, strings, and closed upvalues are visited
231 ** and turned black here. Other objects are marked gray and added
232 ** to appropriate list to be visited (and turned black) later. (Open
233 ** upvalues are already linked in 'headuv' list.)
235 static void reallymarkobject (global_State
*g
, GCObject
*o
) {
241 g
->GCmemtrav
+= sizelstring(gco2ts(o
)->shrlen
);
246 g
->GCmemtrav
+= sizelstring(gco2ts(o
)->u
.lnglen
);
249 case LUA_TUSERDATA
: {
251 markobjectN(g
, gco2u(o
)->metatable
); /* mark its metatable */
253 g
->GCmemtrav
+= sizeudata(gco2u(o
));
254 getuservalue(g
->mainthread
, gco2u(o
), &uvalue
);
255 if (valiswhite(&uvalue
)) { /* markvalue(g, &uvalue); */
256 o
= gcvalue(&uvalue
);
262 linkgclist(gco2lcl(o
), g
->gray
);
266 linkgclist(gco2ccl(o
), g
->gray
);
270 linkgclist(gco2t(o
), g
->gray
);
274 linkgclist(gco2th(o
), g
->gray
);
278 linkgclist(gco2p(o
), g
->gray
);
281 default: lua_assert(0); break;
287 ** mark metamethods for basic types
289 static void markmt (global_State
*g
) {
291 for (i
=0; i
< LUA_NUMTAGS
; i
++)
292 markobjectN(g
, g
->mt
[i
]);
297 ** mark all objects in list of being-finalized
299 static void markbeingfnz (global_State
*g
) {
301 for (o
= g
->tobefnz
; o
!= NULL
; o
= o
->next
)
307 ** Mark all values stored in marked open upvalues from non-marked threads.
308 ** (Values from marked threads were already marked when traversing the
309 ** thread.) Remove from the list threads that no longer have upvalues and
310 ** not-marked threads.
312 static void remarkupvals (global_State
*g
) {
314 lua_State
**p
= &g
->twups
;
315 while ((thread
= *p
) != NULL
) {
316 lua_assert(!isblack(thread
)); /* threads are never black */
317 if (isgray(thread
) && thread
->openupval
!= NULL
)
318 p
= &thread
->twups
; /* keep marked thread with upvalues in the list */
319 else { /* thread is not marked or without upvalues */
321 *p
= thread
->twups
; /* remove thread from the list */
322 thread
->twups
= thread
; /* mark that it is out of list */
323 for (uv
= thread
->openupval
; uv
!= NULL
; uv
= uv
->u
.open
.next
) {
324 if (uv
->u
.open
.touched
) {
325 markvalue(g
, uv
->v
); /* remark upvalue's value */
326 uv
->u
.open
.touched
= 0;
335 ** mark root set and reset all gray lists, to start a new collection
337 static void restartcollection (global_State
*g
) {
338 g
->gray
= g
->grayagain
= NULL
;
339 g
->weak
= g
->allweak
= g
->ephemeron
= NULL
;
340 markobject(g
, g
->mainthread
);
341 markvalue(g
, &g
->l_registry
);
343 markbeingfnz(g
); /* mark any finalizing object left from previous cycle */
346 /* }====================================================== */
350 ** {======================================================
351 ** Traverse functions
352 ** =======================================================
356 ** Traverse a table with weak values and link it to proper list. During
357 ** propagate phase, keep it in 'grayagain' list, to be revisited in the
358 ** atomic phase. In the atomic phase, if table has any white value,
359 ** put it in 'weak' list, to be cleared.
361 static void traverseweakvalue (global_State
*g
, Table
*h
) {
362 Node
*n
, *limit
= gnodelast(h
);
363 /* if there is array part, assume it may have white values (it is not
364 worth traversing it now just to check) */
365 int hasclears
= (h
->sizearray
> 0);
366 for (n
= gnode(h
, 0); n
< limit
; n
++) { /* traverse hash part */
368 if (ttisnil(gval(n
))) /* entry is empty? */
369 removeentry(n
); /* remove it */
371 lua_assert(!ttisnil(gkey(n
)));
372 markvalue(g
, gkey(n
)); /* mark key */
373 if (!hasclears
&& iscleared(g
, gval(n
))) /* is there a white value? */
374 hasclears
= 1; /* table will have to be cleared */
377 if (g
->gcstate
== GCSpropagate
)
378 linkgclist(h
, g
->grayagain
); /* must retraverse it in atomic phase */
380 linkgclist(h
, g
->weak
); /* has to be cleared later */
385 ** Traverse an ephemeron table and link it to proper list. Returns true
386 ** iff any object was marked during this traversal (which implies that
387 ** convergence has to continue). During propagation phase, keep table
388 ** in 'grayagain' list, to be visited again in the atomic phase. In
389 ** the atomic phase, if table has any white->white entry, it has to
390 ** be revisited during ephemeron convergence (as that key may turn
391 ** black). Otherwise, if it has any white key, table has to be cleared
392 ** (in the atomic phase).
394 static int traverseephemeron (global_State
*g
, Table
*h
) {
395 int marked
= 0; /* true if an object is marked in this traversal */
396 int hasclears
= 0; /* true if table has white keys */
397 int hasww
= 0; /* true if table has entry "white-key -> white-value" */
398 Node
*n
, *limit
= gnodelast(h
);
400 /* traverse array part */
401 for (i
= 0; i
< h
->sizearray
; i
++) {
402 if (valiswhite(&h
->array
[i
])) {
404 reallymarkobject(g
, gcvalue(&h
->array
[i
]));
407 /* traverse hash part */
408 for (n
= gnode(h
, 0); n
< limit
; n
++) {
410 if (ttisnil(gval(n
))) /* entry is empty? */
411 removeentry(n
); /* remove it */
412 else if (iscleared(g
, gkey(n
))) { /* key is not marked (yet)? */
413 hasclears
= 1; /* table must be cleared */
414 if (valiswhite(gval(n
))) /* value not marked yet? */
415 hasww
= 1; /* white-white entry */
417 else if (valiswhite(gval(n
))) { /* value not marked yet? */
419 reallymarkobject(g
, gcvalue(gval(n
))); /* mark it now */
422 /* link table into proper list */
423 if (g
->gcstate
== GCSpropagate
)
424 linkgclist(h
, g
->grayagain
); /* must retraverse it in atomic phase */
425 else if (hasww
) /* table has white->white entries? */
426 linkgclist(h
, g
->ephemeron
); /* have to propagate again */
427 else if (hasclears
) /* table has white keys? */
428 linkgclist(h
, g
->allweak
); /* may have to clean white keys */
433 static void traversestrongtable (global_State
*g
, Table
*h
) {
434 Node
*n
, *limit
= gnodelast(h
);
436 for (i
= 0; i
< h
->sizearray
; i
++) /* traverse array part */
437 markvalue(g
, &h
->array
[i
]);
438 for (n
= gnode(h
, 0); n
< limit
; n
++) { /* traverse hash part */
440 if (ttisnil(gval(n
))) /* entry is empty? */
441 removeentry(n
); /* remove it */
443 lua_assert(!ttisnil(gkey(n
)));
444 markvalue(g
, gkey(n
)); /* mark key */
445 markvalue(g
, gval(n
)); /* mark value */
451 static lu_mem
traversetable (global_State
*g
, Table
*h
) {
452 const char *weakkey
, *weakvalue
;
453 const TValue
*mode
= gfasttm(g
, h
->metatable
, TM_MODE
);
454 markobjectN(g
, h
->metatable
);
455 if (mode
&& ttisstring(mode
) && /* is there a weak mode? */
456 ((weakkey
= strchr(svalue(mode
), 'k')),
457 (weakvalue
= strchr(svalue(mode
), 'v')),
458 (weakkey
|| weakvalue
))) { /* is really weak? */
459 black2gray(h
); /* keep table gray */
460 if (!weakkey
) /* strong keys? */
461 traverseweakvalue(g
, h
);
462 else if (!weakvalue
) /* strong values? */
463 traverseephemeron(g
, h
);
465 linkgclist(h
, g
->allweak
); /* nothing to traverse now */
468 traversestrongtable(g
, h
);
469 return sizeof(Table
) + sizeof(TValue
) * h
->sizearray
+
470 sizeof(Node
) * cast(size_t, allocsizenode(h
));
475 ** Traverse a prototype. (While a prototype is being build, its
476 ** arrays can be larger than needed; the extra slots are filled with
477 ** NULL, so the use of 'markobjectN')
479 static int traverseproto (global_State
*g
, Proto
*f
) {
481 if (f
->cache
&& iswhite(f
->cache
))
482 f
->cache
= NULL
; /* allow cache to be collected */
483 markobjectN(g
, f
->source
);
484 for (i
= 0; i
< f
->sizek
; i
++) /* mark literals */
485 markvalue(g
, &f
->k
[i
]);
486 for (i
= 0; i
< f
->sizeupvalues
; i
++) /* mark upvalue names */
487 markobjectN(g
, f
->upvalues
[i
].name
);
488 for (i
= 0; i
< f
->sizep
; i
++) /* mark nested protos */
489 markobjectN(g
, f
->p
[i
]);
490 for (i
= 0; i
< f
->sizelocvars
; i
++) /* mark local-variable names */
491 markobjectN(g
, f
->locvars
[i
].varname
);
492 return sizeof(Proto
) + sizeof(Instruction
) * f
->sizecode
+
493 sizeof(Proto
*) * f
->sizep
+
494 sizeof(TValue
) * f
->sizek
+
495 sizeof(int) * f
->sizelineinfo
+
496 sizeof(LocVar
) * f
->sizelocvars
+
497 sizeof(Upvaldesc
) * f
->sizeupvalues
;
501 static lu_mem
traverseCclosure (global_State
*g
, CClosure
*cl
) {
503 for (i
= 0; i
< cl
->nupvalues
; i
++) /* mark its upvalues */
504 markvalue(g
, &cl
->upvalue
[i
]);
505 return sizeCclosure(cl
->nupvalues
);
509 ** open upvalues point to values in a thread, so those values should
510 ** be marked when the thread is traversed except in the atomic phase
511 ** (because then the value cannot be changed by the thread and the
512 ** thread may not be traversed again)
514 static lu_mem
traverseLclosure (global_State
*g
, LClosure
*cl
) {
516 markobjectN(g
, cl
->p
); /* mark its prototype */
517 for (i
= 0; i
< cl
->nupvalues
; i
++) { /* mark its upvalues */
518 UpVal
*uv
= cl
->upvals
[i
];
520 if (upisopen(uv
) && g
->gcstate
!= GCSinsideatomic
)
521 uv
->u
.open
.touched
= 1; /* can be marked in 'remarkupvals' */
526 return sizeLclosure(cl
->nupvalues
);
530 static lu_mem
traversethread (global_State
*g
, lua_State
*th
) {
533 return 1; /* stack not completely built yet */
534 lua_assert(g
->gcstate
== GCSinsideatomic
||
535 th
->openupval
== NULL
|| isintwups(th
));
536 for (; o
< th
->top
; o
++) /* mark live elements in the stack */
538 if (g
->gcstate
== GCSinsideatomic
) { /* final traversal? */
539 StkId lim
= th
->stack
+ th
->stacksize
; /* real end of stack */
540 for (; o
< lim
; o
++) /* clear not-marked stack slice */
542 /* 'remarkupvals' may have removed thread from 'twups' list */
543 if (!isintwups(th
) && th
->openupval
!= NULL
) {
544 th
->twups
= g
->twups
; /* link it back to the list */
548 else if (g
->gckind
!= KGC_EMERGENCY
)
549 luaD_shrinkstack(th
); /* do not change stack in emergency cycle */
550 return (sizeof(lua_State
) + sizeof(TValue
) * th
->stacksize
+
551 sizeof(CallInfo
) * th
->nci
);
556 ** traverse one gray object, turning it to black (except for threads,
557 ** which are always gray).
559 static void propagatemark (global_State
*g
) {
561 GCObject
*o
= g
->gray
;
562 lua_assert(isgray(o
));
567 g
->gray
= h
->gclist
; /* remove from 'gray' list */
568 size
= traversetable(g
, h
);
572 LClosure
*cl
= gco2lcl(o
);
573 g
->gray
= cl
->gclist
; /* remove from 'gray' list */
574 size
= traverseLclosure(g
, cl
);
578 CClosure
*cl
= gco2ccl(o
);
579 g
->gray
= cl
->gclist
; /* remove from 'gray' list */
580 size
= traverseCclosure(g
, cl
);
584 lua_State
*th
= gco2th(o
);
585 g
->gray
= th
->gclist
; /* remove from 'gray' list */
586 linkgclist(th
, g
->grayagain
); /* insert into 'grayagain' list */
588 size
= traversethread(g
, th
);
593 g
->gray
= p
->gclist
; /* remove from 'gray' list */
594 size
= traverseproto(g
, p
);
597 default: lua_assert(0); return;
599 g
->GCmemtrav
+= size
;
603 static void propagateall (global_State
*g
) {
604 while (g
->gray
) propagatemark(g
);
608 static void convergeephemerons (global_State
*g
) {
612 GCObject
*next
= g
->ephemeron
; /* get ephemeron list */
613 g
->ephemeron
= NULL
; /* tables may return to this list when traversed */
615 while ((w
= next
) != NULL
) {
616 next
= gco2t(w
)->gclist
;
617 if (traverseephemeron(g
, gco2t(w
))) { /* traverse marked some value? */
618 propagateall(g
); /* propagate changes */
619 changed
= 1; /* will have to revisit all ephemeron tables */
625 /* }====================================================== */
629 ** {======================================================
631 ** =======================================================
636 ** clear entries with unmarked keys from all weaktables in list 'l' up
639 static void clearkeys (global_State
*g
, GCObject
*l
, GCObject
*f
) {
640 for (; l
!= f
; l
= gco2t(l
)->gclist
) {
642 Node
*n
, *limit
= gnodelast(h
);
643 for (n
= gnode(h
, 0); n
< limit
; n
++) {
644 if (!ttisnil(gval(n
)) && (iscleared(g
, gkey(n
)))) {
645 setnilvalue(gval(n
)); /* remove value ... */
647 if (ttisnil(gval(n
))) /* is entry empty? */
648 removeentry(n
); /* remove entry from table */
655 ** clear entries with unmarked values from all weaktables in list 'l' up
658 static void clearvalues (global_State
*g
, GCObject
*l
, GCObject
*f
) {
659 for (; l
!= f
; l
= gco2t(l
)->gclist
) {
661 Node
*n
, *limit
= gnodelast(h
);
663 for (i
= 0; i
< h
->sizearray
; i
++) {
664 TValue
*o
= &h
->array
[i
];
665 if (iscleared(g
, o
)) /* value was collected? */
666 setnilvalue(o
); /* remove value */
668 for (n
= gnode(h
, 0); n
< limit
; n
++) {
669 if (!ttisnil(gval(n
)) && iscleared(g
, gval(n
))) {
670 setnilvalue(gval(n
)); /* remove value ... */
671 removeentry(n
); /* and remove entry from table */
678 void luaC_upvdeccount (lua_State
*L
, UpVal
*uv
) {
679 lua_assert(uv
->refcount
> 0);
681 if (uv
->refcount
== 0 && !upisopen(uv
))
686 static void freeLclosure (lua_State
*L
, LClosure
*cl
) {
688 for (i
= 0; i
< cl
->nupvalues
; i
++) {
689 UpVal
*uv
= cl
->upvals
[i
];
691 luaC_upvdeccount(L
, uv
);
693 luaM_freemem(L
, cl
, sizeLclosure(cl
->nupvalues
));
697 static void freeobj (lua_State
*L
, GCObject
*o
) {
699 case LUA_TPROTO
: luaF_freeproto(L
, gco2p(o
)); break;
701 freeLclosure(L
, gco2lcl(o
));
705 luaM_freemem(L
, o
, sizeCclosure(gco2ccl(o
)->nupvalues
));
708 case LUA_TTABLE
: luaH_free(L
, gco2t(o
)); break;
709 case LUA_TTHREAD
: luaE_freethread(L
, gco2th(o
)); break;
710 case LUA_TUSERDATA
: luaM_freemem(L
, o
, sizeudata(gco2u(o
))); break;
712 luaS_remove(L
, gco2ts(o
)); /* remove it from hash table */
713 luaM_freemem(L
, o
, sizelstring(gco2ts(o
)->shrlen
));
716 luaM_freemem(L
, o
, sizelstring(gco2ts(o
)->u
.lnglen
));
719 default: lua_assert(0);
724 #define sweepwholelist(L,p) sweeplist(L,p,MAX_LUMEM)
725 static GCObject
**sweeplist (lua_State
*L
, GCObject
**p
, lu_mem count
);
729 ** sweep at most 'count' elements from a list of GCObjects erasing dead
730 ** objects, where a dead object is one marked with the old (non current)
731 ** white; change all non-dead objects back to white, preparing for next
732 ** collection cycle. Return where to continue the traversal or NULL if
735 static GCObject
**sweeplist (lua_State
*L
, GCObject
**p
, lu_mem count
) {
736 global_State
*g
= G(L
);
737 int ow
= otherwhite(g
);
738 int white
= luaC_white(g
); /* current white */
739 while (*p
!= NULL
&& count
-- > 0) {
741 int marked
= curr
->marked
;
742 if (isdeadm(ow
, marked
)) { /* is 'curr' dead? */
743 *p
= curr
->next
; /* remove 'curr' from list */
744 freeobj(L
, curr
); /* erase 'curr' */
746 else { /* change mark to 'white' */
747 curr
->marked
= cast_byte((marked
& maskcolors
) | white
);
748 p
= &curr
->next
; /* go to next element */
751 return (*p
== NULL
) ? NULL
: p
;
756 ** sweep a list until a live object (or end of list)
758 static GCObject
**sweeptolive (lua_State
*L
, GCObject
**p
) {
761 p
= sweeplist(L
, p
, 1);
766 /* }====================================================== */
770 ** {======================================================
772 ** =======================================================
776 ** If possible, shrink string table
778 static void checkSizes (lua_State
*L
, global_State
*g
) {
779 if (g
->gckind
!= KGC_EMERGENCY
) {
780 l_mem olddebt
= g
->GCdebt
;
781 if (g
->strt
.nuse
< g
->strt
.size
/ 4) /* string table too big? */
782 luaS_resize(L
, g
->strt
.size
/ 2); /* shrink it a little */
783 g
->GCestimate
+= g
->GCdebt
- olddebt
; /* update estimate */
788 static GCObject
*udata2finalize (global_State
*g
) {
789 GCObject
*o
= g
->tobefnz
; /* get first element */
790 lua_assert(tofinalize(o
));
791 g
->tobefnz
= o
->next
; /* remove it from 'tobefnz' list */
792 o
->next
= g
->allgc
; /* return it to 'allgc' list */
794 resetbit(o
->marked
, FINALIZEDBIT
); /* object is "normal" again */
796 makewhite(g
, o
); /* "sweep" object */
801 static void dothecall (lua_State
*L
, void *ud
) {
803 luaD_callnoyield(L
, L
->top
- 2, 0);
807 static void GCTM (lua_State
*L
, int propagateerrors
) {
808 global_State
*g
= G(L
);
811 setgcovalue(L
, &v
, udata2finalize(g
));
812 tm
= luaT_gettmbyobj(L
, &v
, TM_GC
);
813 if (tm
!= NULL
&& ttisfunction(tm
)) { /* is there a finalizer? */
815 lu_byte oldah
= L
->allowhook
;
816 int running
= g
->gcrunning
;
817 L
->allowhook
= 0; /* stop debug hooks during GC metamethod */
818 g
->gcrunning
= 0; /* avoid GC steps */
819 setobj2s(L
, L
->top
, tm
); /* push finalizer... */
820 setobj2s(L
, L
->top
+ 1, &v
); /* ... and its argument */
821 L
->top
+= 2; /* and (next line) call the finalizer */
822 L
->ci
->callstatus
|= CIST_FIN
; /* will run a finalizer */
823 status
= luaD_pcall(L
, dothecall
, NULL
, savestack(L
, L
->top
- 2), 0);
824 L
->ci
->callstatus
&= ~CIST_FIN
; /* not running a finalizer anymore */
825 L
->allowhook
= oldah
; /* restore hooks */
826 g
->gcrunning
= running
; /* restore state */
827 if (status
!= LUA_OK
&& propagateerrors
) { /* error while running __gc? */
828 if (status
== LUA_ERRRUN
) { /* is there an error object? */
829 const char *msg
= (ttisstring(L
->top
- 1))
832 luaO_pushfstring(L
, "error in __gc metamethod (%s)", msg
);
833 status
= LUA_ERRGCMM
; /* error in __gc metamethod */
835 luaD_throw(L
, status
); /* re-throw error */
842 ** call a few (up to 'g->gcfinnum') finalizers
844 static int runafewfinalizers (lua_State
*L
) {
845 global_State
*g
= G(L
);
847 lua_assert(!g
->tobefnz
|| g
->gcfinnum
> 0);
848 for (i
= 0; g
->tobefnz
&& i
< g
->gcfinnum
; i
++)
849 GCTM(L
, 1); /* call one finalizer */
850 g
->gcfinnum
= (!g
->tobefnz
) ? 0 /* nothing more to finalize? */
851 : g
->gcfinnum
* 2; /* else call a few more next time */
857 ** call all pending finalizers
859 static void callallpendingfinalizers (lua_State
*L
) {
860 global_State
*g
= G(L
);
867 ** find last 'next' field in list 'p' list (to add elements in its end)
869 static GCObject
**findlast (GCObject
**p
) {
877 ** move all unreachable objects (or 'all' objects) that need
878 ** finalization from list 'finobj' to list 'tobefnz' (to be finalized)
880 static void separatetobefnz (global_State
*g
, int all
) {
882 GCObject
**p
= &g
->finobj
;
883 GCObject
**lastnext
= findlast(&g
->tobefnz
);
884 while ((curr
= *p
) != NULL
) { /* traverse all finalizable objects */
885 lua_assert(tofinalize(curr
));
886 if (!(iswhite(curr
) || all
)) /* not being collected? */
887 p
= &curr
->next
; /* don't bother with it */
889 *p
= curr
->next
; /* remove 'curr' from 'finobj' list */
890 curr
->next
= *lastnext
; /* link at the end of 'tobefnz' list */
892 lastnext
= &curr
->next
;
899 ** if object 'o' has a finalizer, remove it from 'allgc' list (must
900 ** search the list to find it) and link it in 'finobj' list.
902 void luaC_checkfinalizer (lua_State
*L
, GCObject
*o
, Table
*mt
) {
903 global_State
*g
= G(L
);
904 if (tofinalize(o
) || /* obj. is already marked... */
905 gfasttm(g
, mt
, TM_GC
) == NULL
) /* or has no finalizer? */
906 return; /* nothing to be done */
907 else { /* move 'o' to 'finobj' list */
909 if (issweepphase(g
)) {
910 makewhite(g
, o
); /* "sweep" object 'o' */
911 if (g
->sweepgc
== &o
->next
) /* should not remove 'sweepgc' object */
912 g
->sweepgc
= sweeptolive(L
, g
->sweepgc
); /* change 'sweepgc' */
914 /* search for pointer pointing to 'o' */
915 for (p
= &g
->allgc
; *p
!= o
; p
= &(*p
)->next
) { /* empty */ }
916 *p
= o
->next
; /* remove 'o' from 'allgc' list */
917 o
->next
= g
->finobj
; /* link it in 'finobj' list */
919 l_setbit(o
->marked
, FINALIZEDBIT
); /* mark it as such */
923 /* }====================================================== */
928 ** {======================================================
930 ** =======================================================
935 ** Set a reasonable "time" to wait before starting a new GC cycle; cycle
936 ** will start when memory use hits threshold. (Division by 'estimate'
937 ** should be OK: it cannot be zero (because Lua cannot even start with
938 ** less than PAUSEADJ bytes).
940 static void setpause (global_State
*g
) {
941 l_mem threshold
, debt
;
942 l_mem estimate
= g
->GCestimate
/ PAUSEADJ
; /* adjust 'estimate' */
943 lua_assert(estimate
> 0);
944 threshold
= (g
->gcpause
< MAX_LMEM
/ estimate
) /* overflow? */
945 ? estimate
* g
->gcpause
/* no overflow */
946 : MAX_LMEM
; /* overflow; truncate to maximum */
947 debt
= gettotalbytes(g
) - threshold
;
948 luaE_setdebt(g
, debt
);
953 ** Enter first sweep phase.
954 ** The call to 'sweeplist' tries to make pointer point to an object
955 ** inside the list (instead of to the header), so that the real sweep do
956 ** not need to skip objects created between "now" and the start of the
959 static void entersweep (lua_State
*L
) {
960 global_State
*g
= G(L
);
961 g
->gcstate
= GCSswpallgc
;
962 lua_assert(g
->sweepgc
== NULL
);
963 g
->sweepgc
= sweeplist(L
, &g
->allgc
, 1);
967 void luaC_freeallobjects (lua_State
*L
) {
968 global_State
*g
= G(L
);
969 separatetobefnz(g
, 1); /* separate all objects with finalizers */
970 lua_assert(g
->finobj
== NULL
);
971 callallpendingfinalizers(L
);
972 lua_assert(g
->tobefnz
== NULL
);
973 g
->currentwhite
= WHITEBITS
; /* this "white" makes all objects look dead */
974 g
->gckind
= KGC_NORMAL
;
975 sweepwholelist(L
, &g
->finobj
);
976 sweepwholelist(L
, &g
->allgc
);
977 sweepwholelist(L
, &g
->fixedgc
); /* collect fixed objects */
978 lua_assert(g
->strt
.nuse
== 0);
982 static l_mem
atomic (lua_State
*L
) {
983 global_State
*g
= G(L
);
985 GCObject
*origweak
, *origall
;
986 GCObject
*grayagain
= g
->grayagain
; /* save original list */
987 lua_assert(g
->ephemeron
== NULL
&& g
->weak
== NULL
);
988 lua_assert(!iswhite(g
->mainthread
));
989 g
->gcstate
= GCSinsideatomic
;
990 g
->GCmemtrav
= 0; /* start counting work */
991 markobject(g
, L
); /* mark running thread */
992 /* registry and global metatables may be changed by API */
993 markvalue(g
, &g
->l_registry
);
994 markmt(g
); /* mark global metatables */
995 /* remark occasional upvalues of (maybe) dead threads */
997 propagateall(g
); /* propagate changes */
998 work
= g
->GCmemtrav
; /* stop counting (do not recount 'grayagain') */
1000 propagateall(g
); /* traverse 'grayagain' list */
1001 g
->GCmemtrav
= 0; /* restart counting */
1002 convergeephemerons(g
);
1003 /* at this point, all strongly accessible objects are marked. */
1004 /* Clear values from weak tables, before checking finalizers */
1005 clearvalues(g
, g
->weak
, NULL
);
1006 clearvalues(g
, g
->allweak
, NULL
);
1007 origweak
= g
->weak
; origall
= g
->allweak
;
1008 work
+= g
->GCmemtrav
; /* stop counting (objects being finalized) */
1009 separatetobefnz(g
, 0); /* separate objects to be finalized */
1010 g
->gcfinnum
= 1; /* there may be objects to be finalized */
1011 markbeingfnz(g
); /* mark objects that will be finalized */
1012 propagateall(g
); /* remark, to propagate 'resurrection' */
1013 g
->GCmemtrav
= 0; /* restart counting */
1014 convergeephemerons(g
);
1015 /* at this point, all resurrected objects are marked. */
1016 /* remove dead objects from weak tables */
1017 clearkeys(g
, g
->ephemeron
, NULL
); /* clear keys from all ephemeron tables */
1018 clearkeys(g
, g
->allweak
, NULL
); /* clear keys from all 'allweak' tables */
1019 /* clear values from resurrected weak tables */
1020 clearvalues(g
, g
->weak
, origweak
);
1021 clearvalues(g
, g
->allweak
, origall
);
1023 g
->currentwhite
= cast_byte(otherwhite(g
)); /* flip current white */
1024 work
+= g
->GCmemtrav
; /* complete counting */
1025 return work
; /* estimate of memory marked by 'atomic' */
1029 static lu_mem
sweepstep (lua_State
*L
, global_State
*g
,
1030 int nextstate
, GCObject
**nextlist
) {
1032 l_mem olddebt
= g
->GCdebt
;
1033 g
->sweepgc
= sweeplist(L
, g
->sweepgc
, GCSWEEPMAX
);
1034 g
->GCestimate
+= g
->GCdebt
- olddebt
; /* update estimate */
1035 if (g
->sweepgc
) /* is there still something to sweep? */
1036 return (GCSWEEPMAX
* GCSWEEPCOST
);
1038 /* else enter next state */
1039 g
->gcstate
= nextstate
;
1040 g
->sweepgc
= nextlist
;
1045 static lu_mem
singlestep (lua_State
*L
) {
1046 global_State
*g
= G(L
);
1047 switch (g
->gcstate
) {
1049 g
->GCmemtrav
= g
->strt
.size
* sizeof(GCObject
*);
1050 restartcollection(g
);
1051 g
->gcstate
= GCSpropagate
;
1052 return g
->GCmemtrav
;
1054 case GCSpropagate
: {
1056 lua_assert(g
->gray
);
1058 if (g
->gray
== NULL
) /* no more gray objects? */
1059 g
->gcstate
= GCSatomic
; /* finish propagate phase */
1060 return g
->GCmemtrav
; /* memory traversed in this step */
1064 propagateall(g
); /* make sure gray list is empty */
1065 work
= atomic(L
); /* work is what was traversed by 'atomic' */
1067 g
->GCestimate
= gettotalbytes(g
); /* first estimate */;
1070 case GCSswpallgc
: { /* sweep "regular" objects */
1071 return sweepstep(L
, g
, GCSswpfinobj
, &g
->finobj
);
1073 case GCSswpfinobj
: { /* sweep objects with finalizers */
1074 return sweepstep(L
, g
, GCSswptobefnz
, &g
->tobefnz
);
1076 case GCSswptobefnz
: { /* sweep objects to be finalized */
1077 return sweepstep(L
, g
, GCSswpend
, NULL
);
1079 case GCSswpend
: { /* finish sweeps */
1080 makewhite(g
, g
->mainthread
); /* sweep main thread */
1082 g
->gcstate
= GCScallfin
;
1085 case GCScallfin
: { /* call remaining finalizers */
1086 if (g
->tobefnz
&& g
->gckind
!= KGC_EMERGENCY
) {
1087 int n
= runafewfinalizers(L
);
1088 return (n
* GCFINALIZECOST
);
1090 else { /* emergency mode or no more finalizers */
1091 g
->gcstate
= GCSpause
; /* finish collection */
1095 default: lua_assert(0); return 0;
1101 ** advances the garbage collector until it reaches a state allowed
1104 void luaC_runtilstate (lua_State
*L
, int statesmask
) {
1105 global_State
*g
= G(L
);
1106 while (!testbit(statesmask
, g
->gcstate
))
1112 ** get GC debt and convert it from Kb to 'work units' (avoid zero debt
1115 static l_mem
getdebt (global_State
*g
) {
1116 l_mem debt
= g
->GCdebt
;
1117 int stepmul
= g
->gcstepmul
;
1118 if (debt
<= 0) return 0; /* minimal debt */
1120 debt
= (debt
/ STEPMULADJ
) + 1;
1121 debt
= (debt
< MAX_LMEM
/ stepmul
) ? debt
* stepmul
: MAX_LMEM
;
1127 ** performs a basic GC step when collector is running
1129 void luaC_step (lua_State
*L
) {
1130 global_State
*g
= G(L
);
1131 l_mem debt
= getdebt(g
); /* GC deficit (be paid now) */
1132 if (!g
->gcrunning
) { /* not running? */
1133 luaE_setdebt(g
, -GCSTEPSIZE
* 10); /* avoid being called too often */
1136 do { /* repeat until pause or enough "credit" (negative debt) */
1137 lu_mem work
= singlestep(L
); /* perform one single step */
1139 } while (debt
> -GCSTEPSIZE
&& g
->gcstate
!= GCSpause
);
1140 if (g
->gcstate
== GCSpause
)
1141 setpause(g
); /* pause until next cycle */
1143 debt
= (debt
/ g
->gcstepmul
) * STEPMULADJ
; /* convert 'work units' to Kb */
1144 luaE_setdebt(g
, debt
);
1145 runafewfinalizers(L
);
1151 ** Performs a full GC cycle; if 'isemergency', set a flag to avoid
1152 ** some operations which could change the interpreter state in some
1153 ** unexpected ways (running finalizers and shrinking some structures).
1154 ** Before running the collection, check 'keepinvariant'; if it is true,
1155 ** there may be some objects marked as black, so the collector has
1156 ** to sweep all objects to turn them back to white (as white has not
1157 ** changed, nothing will be collected).
1159 void luaC_fullgc (lua_State
*L
, int isemergency
) {
1160 global_State
*g
= G(L
);
1161 lua_assert(g
->gckind
== KGC_NORMAL
);
1162 if (isemergency
) g
->gckind
= KGC_EMERGENCY
; /* set flag */
1163 if (keepinvariant(g
)) { /* black objects? */
1164 entersweep(L
); /* sweep everything to turn them back to white */
1166 /* finish any pending sweep phase to start a new cycle */
1167 luaC_runtilstate(L
, bitmask(GCSpause
));
1168 luaC_runtilstate(L
, ~bitmask(GCSpause
)); /* start new collection */
1169 luaC_runtilstate(L
, bitmask(GCScallfin
)); /* run up to finalizers */
1170 /* estimate must be correct after a full GC cycle */
1171 lua_assert(g
->GCestimate
== gettotalbytes(g
));
1172 luaC_runtilstate(L
, bitmask(GCSpause
)); /* finish collection */
1173 g
->gckind
= KGC_NORMAL
;
1177 /* }====================================================== */