1dfc11533SChris Williamson /*
2dfc11533SChris Williamson ** $Id: lgc.c,v 2.140.1.3 2014/09/01 16:55:08 roberto Exp $
3dfc11533SChris Williamson ** Garbage Collector
4dfc11533SChris Williamson ** See Copyright Notice in lua.h
5dfc11533SChris Williamson */
6dfc11533SChris Williamson
7dfc11533SChris Williamson #include <sys/zfs_context.h>
8dfc11533SChris Williamson
9dfc11533SChris Williamson #define lgc_c
10dfc11533SChris Williamson #define LUA_CORE
11dfc11533SChris Williamson
12dfc11533SChris Williamson #include "lua.h"
13dfc11533SChris Williamson
14dfc11533SChris Williamson #include "ldebug.h"
15dfc11533SChris Williamson #include "ldo.h"
16dfc11533SChris Williamson #include "lfunc.h"
17dfc11533SChris Williamson #include "lgc.h"
18dfc11533SChris Williamson #include "lmem.h"
19dfc11533SChris Williamson #include "lobject.h"
20dfc11533SChris Williamson #include "lstate.h"
21dfc11533SChris Williamson #include "lstring.h"
22dfc11533SChris Williamson #include "ltable.h"
23dfc11533SChris Williamson #include "ltm.h"
24dfc11533SChris Williamson
25dfc11533SChris Williamson
26dfc11533SChris Williamson
27dfc11533SChris Williamson /*
28dfc11533SChris Williamson ** cost of sweeping one element (the size of a small object divided
29dfc11533SChris Williamson ** by some adjust for the sweep speed)
30dfc11533SChris Williamson */
31dfc11533SChris Williamson #define GCSWEEPCOST ((sizeof(TString) + 4) / 4)
32dfc11533SChris Williamson
33dfc11533SChris Williamson /* maximum number of elements to sweep in each single step */
34dfc11533SChris Williamson #define GCSWEEPMAX (cast_int((GCSTEPSIZE / GCSWEEPCOST) / 4))
35dfc11533SChris Williamson
36dfc11533SChris Williamson /* maximum number of finalizers to call in each GC step */
37dfc11533SChris Williamson #define GCFINALIZENUM 4
38dfc11533SChris Williamson
39dfc11533SChris Williamson
40dfc11533SChris Williamson /*
41dfc11533SChris Williamson ** macro to adjust 'stepmul': 'stepmul' is actually used like
42dfc11533SChris Williamson ** 'stepmul / STEPMULADJ' (value chosen by tests)
43dfc11533SChris Williamson */
44dfc11533SChris Williamson #define STEPMULADJ 200
45dfc11533SChris Williamson
46dfc11533SChris Williamson
47dfc11533SChris Williamson /*
48dfc11533SChris Williamson ** macro to adjust 'pause': 'pause' is actually used like
49dfc11533SChris Williamson ** 'pause / PAUSEADJ' (value chosen by tests)
50dfc11533SChris Williamson */
51dfc11533SChris Williamson #define PAUSEADJ 100
52dfc11533SChris Williamson
53dfc11533SChris Williamson
54dfc11533SChris Williamson /*
55dfc11533SChris Williamson ** 'makewhite' erases all color bits plus the old bit and then
56dfc11533SChris Williamson ** sets only the current white bit
57dfc11533SChris Williamson */
58dfc11533SChris Williamson #define maskcolors (~(bit2mask(BLACKBIT, OLDBIT) | WHITEBITS))
59dfc11533SChris Williamson #define makewhite(g,x) \
60dfc11533SChris Williamson (gch(x)->marked = cast_byte((gch(x)->marked & maskcolors) | luaC_white(g)))
61dfc11533SChris Williamson
62dfc11533SChris Williamson #define white2gray(x) resetbits(gch(x)->marked, WHITEBITS)
63dfc11533SChris Williamson #define black2gray(x) resetbit(gch(x)->marked, BLACKBIT)
64dfc11533SChris Williamson
65dfc11533SChris Williamson
66dfc11533SChris Williamson #define isfinalized(x) testbit(gch(x)->marked, FINALIZEDBIT)
67dfc11533SChris Williamson
68dfc11533SChris Williamson #define checkdeadkey(n) lua_assert(!ttisdeadkey(gkey(n)) || ttisnil(gval(n)))
69dfc11533SChris Williamson
70dfc11533SChris Williamson
71dfc11533SChris Williamson #define checkconsistency(obj) \
72dfc11533SChris Williamson lua_longassert(!iscollectable(obj) || righttt(obj))
73dfc11533SChris Williamson
74dfc11533SChris Williamson
75dfc11533SChris Williamson #define markvalue(g,o) { checkconsistency(o); \
76dfc11533SChris Williamson if (valiswhite(o)) reallymarkobject(g,gcvalue(o)); }
77dfc11533SChris Williamson
78dfc11533SChris Williamson #define markobject(g,t) { if ((t) && iswhite(obj2gco(t))) \
79dfc11533SChris Williamson reallymarkobject(g, obj2gco(t)); }
80dfc11533SChris Williamson
81dfc11533SChris Williamson static void reallymarkobject (global_State *g, GCObject *o);
82dfc11533SChris Williamson
83dfc11533SChris Williamson
84dfc11533SChris Williamson /*
85dfc11533SChris Williamson ** {======================================================
86dfc11533SChris Williamson ** Generic functions
87dfc11533SChris Williamson ** =======================================================
88dfc11533SChris Williamson */
89dfc11533SChris Williamson
90dfc11533SChris Williamson
91dfc11533SChris Williamson /*
92dfc11533SChris Williamson ** one after last element in a hash array
93dfc11533SChris Williamson */
94dfc11533SChris Williamson #define gnodelast(h) gnode(h, cast(size_t, sizenode(h)))
95dfc11533SChris Williamson
96dfc11533SChris Williamson
97dfc11533SChris Williamson /*
98dfc11533SChris Williamson ** link table 'h' into list pointed by 'p'
99dfc11533SChris Williamson */
100dfc11533SChris Williamson #define linktable(h,p) ((h)->gclist = *(p), *(p) = obj2gco(h))
101dfc11533SChris Williamson
102dfc11533SChris Williamson
103dfc11533SChris Williamson /*
104dfc11533SChris Williamson ** if key is not marked, mark its entry as dead (therefore removing it
105dfc11533SChris Williamson ** from the table)
106dfc11533SChris Williamson */
removeentry(Node * n)107dfc11533SChris Williamson static void removeentry (Node *n) {
108dfc11533SChris Williamson lua_assert(ttisnil(gval(n)));
109dfc11533SChris Williamson if (valiswhite(gkey(n)))
110dfc11533SChris Williamson setdeadvalue(gkey(n)); /* unused and unmarked key; remove it */
111dfc11533SChris Williamson }
112dfc11533SChris Williamson
113dfc11533SChris Williamson
114dfc11533SChris Williamson /*
115dfc11533SChris Williamson ** tells whether a key or value can be cleared from a weak
116dfc11533SChris Williamson ** table. Non-collectable objects are never removed from weak
117dfc11533SChris Williamson ** tables. Strings behave as `values', so are never removed too. for
118dfc11533SChris Williamson ** other objects: if really collected, cannot keep them; for objects
119dfc11533SChris Williamson ** being finalized, keep them in keys, but not in values
120dfc11533SChris Williamson */
iscleared(global_State * g,const TValue * o)121dfc11533SChris Williamson static int iscleared (global_State *g, const TValue *o) {
122dfc11533SChris Williamson if (!iscollectable(o)) return 0;
123dfc11533SChris Williamson else if (ttisstring(o)) {
124dfc11533SChris Williamson markobject(g, rawtsvalue(o)); /* strings are `values', so are never weak */
125dfc11533SChris Williamson return 0;
126dfc11533SChris Williamson }
127dfc11533SChris Williamson else return iswhite(gcvalue(o));
128dfc11533SChris Williamson }
129dfc11533SChris Williamson
130dfc11533SChris Williamson
131dfc11533SChris Williamson /*
132dfc11533SChris Williamson ** barrier that moves collector forward, that is, mark the white object
133dfc11533SChris Williamson ** being pointed by a black object.
134dfc11533SChris Williamson */
luaC_barrier_(lua_State * L,GCObject * o,GCObject * v)135dfc11533SChris Williamson void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v) {
136dfc11533SChris Williamson global_State *g = G(L);
137dfc11533SChris Williamson lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
138dfc11533SChris Williamson lua_assert(g->gcstate != GCSpause);
139dfc11533SChris Williamson lua_assert(gch(o)->tt != LUA_TTABLE);
140dfc11533SChris Williamson if (keepinvariantout(g)) /* must keep invariant? */
141dfc11533SChris Williamson reallymarkobject(g, v); /* restore invariant */
142dfc11533SChris Williamson else { /* sweep phase */
143dfc11533SChris Williamson lua_assert(issweepphase(g));
144dfc11533SChris Williamson makewhite(g, o); /* mark main obj. as white to avoid other barriers */
145dfc11533SChris Williamson }
146dfc11533SChris Williamson }
147dfc11533SChris Williamson
148dfc11533SChris Williamson
149dfc11533SChris Williamson /*
150dfc11533SChris Williamson ** barrier that moves collector backward, that is, mark the black object
151dfc11533SChris Williamson ** pointing to a white object as gray again. (Current implementation
152dfc11533SChris Williamson ** only works for tables; access to 'gclist' is not uniform across
153dfc11533SChris Williamson ** different types.)
154dfc11533SChris Williamson */
luaC_barrierback_(lua_State * L,GCObject * o)155dfc11533SChris Williamson void luaC_barrierback_ (lua_State *L, GCObject *o) {
156dfc11533SChris Williamson global_State *g = G(L);
157dfc11533SChris Williamson lua_assert(isblack(o) && !isdead(g, o) && gch(o)->tt == LUA_TTABLE);
158dfc11533SChris Williamson black2gray(o); /* make object gray (again) */
159dfc11533SChris Williamson gco2t(o)->gclist = g->grayagain;
160dfc11533SChris Williamson g->grayagain = o;
161dfc11533SChris Williamson }
162dfc11533SChris Williamson
163dfc11533SChris Williamson
164dfc11533SChris Williamson /*
165dfc11533SChris Williamson ** barrier for prototypes. When creating first closure (cache is
166dfc11533SChris Williamson ** NULL), use a forward barrier; this may be the only closure of the
167dfc11533SChris Williamson ** prototype (if it is a "regular" function, with a single instance)
168dfc11533SChris Williamson ** and the prototype may be big, so it is better to avoid traversing
169dfc11533SChris Williamson ** it again. Otherwise, use a backward barrier, to avoid marking all
170dfc11533SChris Williamson ** possible instances.
171dfc11533SChris Williamson */
luaC_barrierproto_(lua_State * L,Proto * p,Closure * c)172dfc11533SChris Williamson LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c) {
173dfc11533SChris Williamson global_State *g = G(L);
174dfc11533SChris Williamson lua_assert(isblack(obj2gco(p)));
175dfc11533SChris Williamson if (p->cache == NULL) { /* first time? */
176dfc11533SChris Williamson luaC_objbarrier(L, p, c);
177dfc11533SChris Williamson }
178dfc11533SChris Williamson else { /* use a backward barrier */
179dfc11533SChris Williamson black2gray(obj2gco(p)); /* make prototype gray (again) */
180dfc11533SChris Williamson p->gclist = g->grayagain;
181dfc11533SChris Williamson g->grayagain = obj2gco(p);
182dfc11533SChris Williamson }
183dfc11533SChris Williamson }
184dfc11533SChris Williamson
185dfc11533SChris Williamson
186dfc11533SChris Williamson /*
187dfc11533SChris Williamson ** check color (and invariants) for an upvalue that was closed,
188dfc11533SChris Williamson ** i.e., moved into the 'allgc' list
189dfc11533SChris Williamson */
luaC_checkupvalcolor(global_State * g,UpVal * uv)190dfc11533SChris Williamson void luaC_checkupvalcolor (global_State *g, UpVal *uv) {
191dfc11533SChris Williamson GCObject *o = obj2gco(uv);
192dfc11533SChris Williamson lua_assert(!isblack(o)); /* open upvalues are never black */
193dfc11533SChris Williamson if (isgray(o)) {
194dfc11533SChris Williamson if (keepinvariant(g)) {
195dfc11533SChris Williamson resetoldbit(o); /* see MOVE OLD rule */
196dfc11533SChris Williamson gray2black(o); /* it is being visited now */
197dfc11533SChris Williamson markvalue(g, uv->v);
198dfc11533SChris Williamson }
199dfc11533SChris Williamson else {
200dfc11533SChris Williamson lua_assert(issweepphase(g));
201dfc11533SChris Williamson makewhite(g, o);
202dfc11533SChris Williamson }
203dfc11533SChris Williamson }
204dfc11533SChris Williamson }
205dfc11533SChris Williamson
206dfc11533SChris Williamson
207dfc11533SChris Williamson /*
208dfc11533SChris Williamson ** create a new collectable object (with given type and size) and link
209dfc11533SChris Williamson ** it to '*list'. 'offset' tells how many bytes to allocate before the
210dfc11533SChris Williamson ** object itself (used only by states).
211dfc11533SChris Williamson */
luaC_newobj(lua_State * L,int tt,size_t sz,GCObject ** list,int offset)212dfc11533SChris Williamson GCObject *luaC_newobj (lua_State *L, int tt, size_t sz, GCObject **list,
213dfc11533SChris Williamson int offset) {
214dfc11533SChris Williamson global_State *g = G(L);
215dfc11533SChris Williamson char *raw = cast(char *, luaM_newobject(L, novariant(tt), sz));
216dfc11533SChris Williamson GCObject *o = obj2gco(raw + offset);
217dfc11533SChris Williamson if (list == NULL)
218dfc11533SChris Williamson list = &g->allgc; /* standard list for collectable objects */
219dfc11533SChris Williamson gch(o)->marked = luaC_white(g);
220dfc11533SChris Williamson gch(o)->tt = tt;
221dfc11533SChris Williamson gch(o)->next = *list;
222dfc11533SChris Williamson *list = o;
223dfc11533SChris Williamson return o;
224dfc11533SChris Williamson }
225dfc11533SChris Williamson
226dfc11533SChris Williamson /* }====================================================== */
227dfc11533SChris Williamson
228dfc11533SChris Williamson
229dfc11533SChris Williamson
230dfc11533SChris Williamson /*
231dfc11533SChris Williamson ** {======================================================
232dfc11533SChris Williamson ** Mark functions
233dfc11533SChris Williamson ** =======================================================
234dfc11533SChris Williamson */
235dfc11533SChris Williamson
236dfc11533SChris Williamson
237dfc11533SChris Williamson /*
238dfc11533SChris Williamson ** mark an object. Userdata, strings, and closed upvalues are visited
239dfc11533SChris Williamson ** and turned black here. Other objects are marked gray and added
240dfc11533SChris Williamson ** to appropriate list to be visited (and turned black) later. (Open
241dfc11533SChris Williamson ** upvalues are already linked in 'headuv' list.)
242dfc11533SChris Williamson */
reallymarkobject(global_State * g,GCObject * o)243dfc11533SChris Williamson static void reallymarkobject (global_State *g, GCObject *o) {
244dfc11533SChris Williamson lu_mem size;
245dfc11533SChris Williamson white2gray(o);
246dfc11533SChris Williamson switch (gch(o)->tt) {
247dfc11533SChris Williamson case LUA_TSHRSTR:
248dfc11533SChris Williamson case LUA_TLNGSTR: {
249dfc11533SChris Williamson size = sizestring(gco2ts(o));
250dfc11533SChris Williamson break; /* nothing else to mark; make it black */
251dfc11533SChris Williamson }
252dfc11533SChris Williamson case LUA_TUSERDATA: {
253dfc11533SChris Williamson Table *mt = gco2u(o)->metatable;
254dfc11533SChris Williamson markobject(g, mt);
255dfc11533SChris Williamson markobject(g, gco2u(o)->env);
256dfc11533SChris Williamson size = sizeudata(gco2u(o));
257dfc11533SChris Williamson break;
258dfc11533SChris Williamson }
259dfc11533SChris Williamson case LUA_TUPVAL: {
260dfc11533SChris Williamson UpVal *uv = gco2uv(o);
261dfc11533SChris Williamson markvalue(g, uv->v);
262dfc11533SChris Williamson if (uv->v != &uv->u.value) /* open? */
263dfc11533SChris Williamson return; /* open upvalues remain gray */
264dfc11533SChris Williamson size = sizeof(UpVal);
265dfc11533SChris Williamson break;
266dfc11533SChris Williamson }
267dfc11533SChris Williamson case LUA_TLCL: {
268dfc11533SChris Williamson gco2lcl(o)->gclist = g->gray;
269dfc11533SChris Williamson g->gray = o;
270dfc11533SChris Williamson return;
271dfc11533SChris Williamson }
272dfc11533SChris Williamson case LUA_TCCL: {
273dfc11533SChris Williamson gco2ccl(o)->gclist = g->gray;
274dfc11533SChris Williamson g->gray = o;
275dfc11533SChris Williamson return;
276dfc11533SChris Williamson }
277dfc11533SChris Williamson case LUA_TTABLE: {
278dfc11533SChris Williamson linktable(gco2t(o), &g->gray);
279dfc11533SChris Williamson return;
280dfc11533SChris Williamson }
281dfc11533SChris Williamson case LUA_TTHREAD: {
282dfc11533SChris Williamson gco2th(o)->gclist = g->gray;
283dfc11533SChris Williamson g->gray = o;
284dfc11533SChris Williamson return;
285dfc11533SChris Williamson }
286dfc11533SChris Williamson case LUA_TPROTO: {
287dfc11533SChris Williamson gco2p(o)->gclist = g->gray;
288dfc11533SChris Williamson g->gray = o;
289dfc11533SChris Williamson return;
290dfc11533SChris Williamson }
291dfc11533SChris Williamson default: lua_assert(0); return;
292dfc11533SChris Williamson }
293dfc11533SChris Williamson gray2black(o);
294dfc11533SChris Williamson g->GCmemtrav += size;
295dfc11533SChris Williamson }
296dfc11533SChris Williamson
297dfc11533SChris Williamson
298dfc11533SChris Williamson /*
299dfc11533SChris Williamson ** mark metamethods for basic types
300dfc11533SChris Williamson */
markmt(global_State * g)301dfc11533SChris Williamson static void markmt (global_State *g) {
302dfc11533SChris Williamson int i;
303dfc11533SChris Williamson for (i=0; i < LUA_NUMTAGS; i++)
304dfc11533SChris Williamson markobject(g, g->mt[i]);
305dfc11533SChris Williamson }
306dfc11533SChris Williamson
307dfc11533SChris Williamson
308dfc11533SChris Williamson /*
309dfc11533SChris Williamson ** mark all objects in list of being-finalized
310dfc11533SChris Williamson */
markbeingfnz(global_State * g)311dfc11533SChris Williamson static void markbeingfnz (global_State *g) {
312dfc11533SChris Williamson GCObject *o;
313dfc11533SChris Williamson for (o = g->tobefnz; o != NULL; o = gch(o)->next) {
314dfc11533SChris Williamson makewhite(g, o);
315dfc11533SChris Williamson reallymarkobject(g, o);
316dfc11533SChris Williamson }
317dfc11533SChris Williamson }
318dfc11533SChris Williamson
319dfc11533SChris Williamson
320dfc11533SChris Williamson /*
321dfc11533SChris Williamson ** mark all values stored in marked open upvalues. (See comment in
322dfc11533SChris Williamson ** 'lstate.h'.)
323dfc11533SChris Williamson */
remarkupvals(global_State * g)324dfc11533SChris Williamson static void remarkupvals (global_State *g) {
325dfc11533SChris Williamson UpVal *uv;
326dfc11533SChris Williamson for (uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next) {
327dfc11533SChris Williamson if (isgray(obj2gco(uv)))
328dfc11533SChris Williamson markvalue(g, uv->v);
329dfc11533SChris Williamson }
330dfc11533SChris Williamson }
331dfc11533SChris Williamson
332dfc11533SChris Williamson
333dfc11533SChris Williamson /*
334dfc11533SChris Williamson ** mark root set and reset all gray lists, to start a new
335dfc11533SChris Williamson ** incremental (or full) collection
336dfc11533SChris Williamson */
restartcollection(global_State * g)337dfc11533SChris Williamson static void restartcollection (global_State *g) {
338dfc11533SChris Williamson g->gray = g->grayagain = NULL;
339dfc11533SChris Williamson g->weak = g->allweak = g->ephemeron = NULL;
340dfc11533SChris Williamson markobject(g, g->mainthread);
341dfc11533SChris Williamson markvalue(g, &g->l_registry);
342dfc11533SChris Williamson markmt(g);
343dfc11533SChris Williamson markbeingfnz(g); /* mark any finalizing object left from previous cycle */
344dfc11533SChris Williamson }
345dfc11533SChris Williamson
346dfc11533SChris Williamson /* }====================================================== */
347dfc11533SChris Williamson
348dfc11533SChris Williamson
349dfc11533SChris Williamson /*
350dfc11533SChris Williamson ** {======================================================
351dfc11533SChris Williamson ** Traverse functions
352dfc11533SChris Williamson ** =======================================================
353dfc11533SChris Williamson */
354dfc11533SChris Williamson
traverseweakvalue(global_State * g,Table * h)355dfc11533SChris Williamson static void traverseweakvalue (global_State *g, Table *h) {
356dfc11533SChris Williamson Node *n, *limit = gnodelast(h);
357dfc11533SChris Williamson /* if there is array part, assume it may have white values (do not
358dfc11533SChris Williamson traverse it just to check) */
359dfc11533SChris Williamson int hasclears = (h->sizearray > 0);
360dfc11533SChris Williamson for (n = gnode(h, 0); n < limit; n++) {
361dfc11533SChris Williamson checkdeadkey(n);
362dfc11533SChris Williamson if (ttisnil(gval(n))) /* entry is empty? */
363dfc11533SChris Williamson removeentry(n); /* remove it */
364dfc11533SChris Williamson else {
365dfc11533SChris Williamson lua_assert(!ttisnil(gkey(n)));
366dfc11533SChris Williamson markvalue(g, gkey(n)); /* mark key */
367dfc11533SChris Williamson if (!hasclears && iscleared(g, gval(n))) /* is there a white value? */
368dfc11533SChris Williamson hasclears = 1; /* table will have to be cleared */
369dfc11533SChris Williamson }
370dfc11533SChris Williamson }
371dfc11533SChris Williamson if (hasclears)
372dfc11533SChris Williamson linktable(h, &g->weak); /* has to be cleared later */
373dfc11533SChris Williamson else /* no white values */
374dfc11533SChris Williamson linktable(h, &g->grayagain); /* no need to clean */
375dfc11533SChris Williamson }
376dfc11533SChris Williamson
377dfc11533SChris Williamson
traverseephemeron(global_State * g,Table * h)378dfc11533SChris Williamson static int traverseephemeron (global_State *g, Table *h) {
379dfc11533SChris Williamson int marked = 0; /* true if an object is marked in this traversal */
380dfc11533SChris Williamson int hasclears = 0; /* true if table has white keys */
381dfc11533SChris Williamson int prop = 0; /* true if table has entry "white-key -> white-value" */
382dfc11533SChris Williamson Node *n, *limit = gnodelast(h);
383dfc11533SChris Williamson int i;
384dfc11533SChris Williamson /* traverse array part (numeric keys are 'strong') */
385dfc11533SChris Williamson for (i = 0; i < h->sizearray; i++) {
386dfc11533SChris Williamson if (valiswhite(&h->array[i])) {
387dfc11533SChris Williamson marked = 1;
388dfc11533SChris Williamson reallymarkobject(g, gcvalue(&h->array[i]));
389dfc11533SChris Williamson }
390dfc11533SChris Williamson }
391dfc11533SChris Williamson /* traverse hash part */
392dfc11533SChris Williamson for (n = gnode(h, 0); n < limit; n++) {
393dfc11533SChris Williamson checkdeadkey(n);
394dfc11533SChris Williamson if (ttisnil(gval(n))) /* entry is empty? */
395dfc11533SChris Williamson removeentry(n); /* remove it */
396dfc11533SChris Williamson else if (iscleared(g, gkey(n))) { /* key is not marked (yet)? */
397dfc11533SChris Williamson hasclears = 1; /* table must be cleared */
398dfc11533SChris Williamson if (valiswhite(gval(n))) /* value not marked yet? */
399dfc11533SChris Williamson prop = 1; /* must propagate again */
400dfc11533SChris Williamson }
401dfc11533SChris Williamson else if (valiswhite(gval(n))) { /* value not marked yet? */
402dfc11533SChris Williamson marked = 1;
403dfc11533SChris Williamson reallymarkobject(g, gcvalue(gval(n))); /* mark it now */
404dfc11533SChris Williamson }
405dfc11533SChris Williamson }
406dfc11533SChris Williamson if (g->gcstate != GCSatomic || prop)
407dfc11533SChris Williamson linktable(h, &g->ephemeron); /* have to propagate again */
408dfc11533SChris Williamson else if (hasclears) /* does table have white keys? */
409dfc11533SChris Williamson linktable(h, &g->allweak); /* may have to clean white keys */
410dfc11533SChris Williamson else /* no white keys */
411dfc11533SChris Williamson linktable(h, &g->grayagain); /* no need to clean */
412dfc11533SChris Williamson return marked;
413dfc11533SChris Williamson }
414dfc11533SChris Williamson
415dfc11533SChris Williamson
traversestrongtable(global_State * g,Table * h)416dfc11533SChris Williamson static void traversestrongtable (global_State *g, Table *h) {
417dfc11533SChris Williamson Node *n, *limit = gnodelast(h);
418dfc11533SChris Williamson int i;
419dfc11533SChris Williamson for (i = 0; i < h->sizearray; i++) /* traverse array part */
420dfc11533SChris Williamson markvalue(g, &h->array[i]);
421dfc11533SChris Williamson for (n = gnode(h, 0); n < limit; n++) { /* traverse hash part */
422dfc11533SChris Williamson checkdeadkey(n);
423dfc11533SChris Williamson if (ttisnil(gval(n))) /* entry is empty? */
424dfc11533SChris Williamson removeentry(n); /* remove it */
425dfc11533SChris Williamson else {
426dfc11533SChris Williamson lua_assert(!ttisnil(gkey(n)));
427dfc11533SChris Williamson markvalue(g, gkey(n)); /* mark key */
428dfc11533SChris Williamson markvalue(g, gval(n)); /* mark value */
429dfc11533SChris Williamson }
430dfc11533SChris Williamson }
431dfc11533SChris Williamson }
432dfc11533SChris Williamson
433dfc11533SChris Williamson
traversetable(global_State * g,Table * h)434dfc11533SChris Williamson static lu_mem traversetable (global_State *g, Table *h) {
435dfc11533SChris Williamson const char *weakkey, *weakvalue;
436dfc11533SChris Williamson const TValue *mode = gfasttm(g, h->metatable, TM_MODE);
437dfc11533SChris Williamson markobject(g, h->metatable);
438dfc11533SChris Williamson if (mode && ttisstring(mode) && /* is there a weak mode? */
439dfc11533SChris Williamson ((weakkey = strchr(svalue(mode), 'k')),
440dfc11533SChris Williamson (weakvalue = strchr(svalue(mode), 'v')),
441dfc11533SChris Williamson (weakkey || weakvalue))) { /* is really weak? */
442dfc11533SChris Williamson black2gray(obj2gco(h)); /* keep table gray */
443dfc11533SChris Williamson if (!weakkey) /* strong keys? */
444dfc11533SChris Williamson traverseweakvalue(g, h);
445dfc11533SChris Williamson else if (!weakvalue) /* strong values? */
446dfc11533SChris Williamson traverseephemeron(g, h);
447dfc11533SChris Williamson else /* all weak */
448dfc11533SChris Williamson linktable(h, &g->allweak); /* nothing to traverse now */
449dfc11533SChris Williamson }
450dfc11533SChris Williamson else /* not weak */
451dfc11533SChris Williamson traversestrongtable(g, h);
452dfc11533SChris Williamson return sizeof(Table) + sizeof(TValue) * h->sizearray +
453dfc11533SChris Williamson sizeof(Node) * cast(size_t, sizenode(h));
454dfc11533SChris Williamson }
455dfc11533SChris Williamson
456dfc11533SChris Williamson
traverseproto(global_State * g,Proto * f)457dfc11533SChris Williamson static int traverseproto (global_State *g, Proto *f) {
458dfc11533SChris Williamson int i;
459dfc11533SChris Williamson if (f->cache && iswhite(obj2gco(f->cache)))
460dfc11533SChris Williamson f->cache = NULL; /* allow cache to be collected */
461dfc11533SChris Williamson markobject(g, f->source);
462dfc11533SChris Williamson for (i = 0; i < f->sizek; i++) /* mark literals */
463dfc11533SChris Williamson markvalue(g, &f->k[i]);
464dfc11533SChris Williamson for (i = 0; i < f->sizeupvalues; i++) /* mark upvalue names */
465dfc11533SChris Williamson markobject(g, f->upvalues[i].name);
466dfc11533SChris Williamson for (i = 0; i < f->sizep; i++) /* mark nested protos */
467dfc11533SChris Williamson markobject(g, f->p[i]);
468dfc11533SChris Williamson for (i = 0; i < f->sizelocvars; i++) /* mark local-variable names */
469dfc11533SChris Williamson markobject(g, f->locvars[i].varname);
470dfc11533SChris Williamson return sizeof(Proto) + sizeof(Instruction) * f->sizecode +
471dfc11533SChris Williamson sizeof(Proto *) * f->sizep +
472dfc11533SChris Williamson sizeof(TValue) * f->sizek +
473dfc11533SChris Williamson sizeof(int) * f->sizelineinfo +
474dfc11533SChris Williamson sizeof(LocVar) * f->sizelocvars +
475dfc11533SChris Williamson sizeof(Upvaldesc) * f->sizeupvalues;
476dfc11533SChris Williamson }
477dfc11533SChris Williamson
478dfc11533SChris Williamson
traverseCclosure(global_State * g,CClosure * cl)479dfc11533SChris Williamson static lu_mem traverseCclosure (global_State *g, CClosure *cl) {
480dfc11533SChris Williamson int i;
481dfc11533SChris Williamson for (i = 0; i < cl->nupvalues; i++) /* mark its upvalues */
482dfc11533SChris Williamson markvalue(g, &cl->upvalue[i]);
483dfc11533SChris Williamson return sizeCclosure(cl->nupvalues);
484dfc11533SChris Williamson }
485dfc11533SChris Williamson
traverseLclosure(global_State * g,LClosure * cl)486dfc11533SChris Williamson static lu_mem traverseLclosure (global_State *g, LClosure *cl) {
487dfc11533SChris Williamson int i;
488dfc11533SChris Williamson markobject(g, cl->p); /* mark its prototype */
489dfc11533SChris Williamson for (i = 0; i < cl->nupvalues; i++) /* mark its upvalues */
490dfc11533SChris Williamson markobject(g, cl->upvals[i]);
491dfc11533SChris Williamson return sizeLclosure(cl->nupvalues);
492dfc11533SChris Williamson }
493dfc11533SChris Williamson
494dfc11533SChris Williamson
traversestack(global_State * g,lua_State * th)495dfc11533SChris Williamson static lu_mem traversestack (global_State *g, lua_State *th) {
496dfc11533SChris Williamson int n = 0;
497dfc11533SChris Williamson StkId o = th->stack;
498dfc11533SChris Williamson if (o == NULL)
499dfc11533SChris Williamson return 1; /* stack not completely built yet */
500dfc11533SChris Williamson for (; o < th->top; o++) /* mark live elements in the stack */
501dfc11533SChris Williamson markvalue(g, o);
502dfc11533SChris Williamson if (g->gcstate == GCSatomic) { /* final traversal? */
503dfc11533SChris Williamson StkId lim = th->stack + th->stacksize; /* real end of stack */
504dfc11533SChris Williamson for (; o < lim; o++) /* clear not-marked stack slice */
505dfc11533SChris Williamson setnilvalue(o);
506dfc11533SChris Williamson }
507dfc11533SChris Williamson else { /* count call infos to compute size */
508dfc11533SChris Williamson CallInfo *ci;
509dfc11533SChris Williamson for (ci = &th->base_ci; ci != th->ci; ci = ci->next)
510dfc11533SChris Williamson n++;
511dfc11533SChris Williamson }
512dfc11533SChris Williamson return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
513dfc11533SChris Williamson sizeof(CallInfo) * n;
514dfc11533SChris Williamson }
515dfc11533SChris Williamson
516dfc11533SChris Williamson
517dfc11533SChris Williamson /*
518dfc11533SChris Williamson ** traverse one gray object, turning it to black (except for threads,
519dfc11533SChris Williamson ** which are always gray).
520dfc11533SChris Williamson */
propagatemark(global_State * g)521dfc11533SChris Williamson static void propagatemark (global_State *g) {
522dfc11533SChris Williamson lu_mem size;
523dfc11533SChris Williamson GCObject *o = g->gray;
524dfc11533SChris Williamson lua_assert(isgray(o));
525dfc11533SChris Williamson gray2black(o);
526dfc11533SChris Williamson switch (gch(o)->tt) {
527dfc11533SChris Williamson case LUA_TTABLE: {
528dfc11533SChris Williamson Table *h = gco2t(o);
529dfc11533SChris Williamson g->gray = h->gclist; /* remove from 'gray' list */
530dfc11533SChris Williamson size = traversetable(g, h);
531dfc11533SChris Williamson break;
532dfc11533SChris Williamson }
533dfc11533SChris Williamson case LUA_TLCL: {
534dfc11533SChris Williamson LClosure *cl = gco2lcl(o);
535dfc11533SChris Williamson g->gray = cl->gclist; /* remove from 'gray' list */
536dfc11533SChris Williamson size = traverseLclosure(g, cl);
537dfc11533SChris Williamson break;
538dfc11533SChris Williamson }
539dfc11533SChris Williamson case LUA_TCCL: {
540dfc11533SChris Williamson CClosure *cl = gco2ccl(o);
541dfc11533SChris Williamson g->gray = cl->gclist; /* remove from 'gray' list */
542dfc11533SChris Williamson size = traverseCclosure(g, cl);
543dfc11533SChris Williamson break;
544dfc11533SChris Williamson }
545dfc11533SChris Williamson case LUA_TTHREAD: {
546dfc11533SChris Williamson lua_State *th = gco2th(o);
547dfc11533SChris Williamson g->gray = th->gclist; /* remove from 'gray' list */
548dfc11533SChris Williamson th->gclist = g->grayagain;
549dfc11533SChris Williamson g->grayagain = o; /* insert into 'grayagain' list */
550dfc11533SChris Williamson black2gray(o);
551dfc11533SChris Williamson size = traversestack(g, th);
552dfc11533SChris Williamson break;
553dfc11533SChris Williamson }
554dfc11533SChris Williamson case LUA_TPROTO: {
555dfc11533SChris Williamson Proto *p = gco2p(o);
556dfc11533SChris Williamson g->gray = p->gclist; /* remove from 'gray' list */
557dfc11533SChris Williamson size = traverseproto(g, p);
558dfc11533SChris Williamson break;
559dfc11533SChris Williamson }
560dfc11533SChris Williamson default: lua_assert(0); return;
561dfc11533SChris Williamson }
562dfc11533SChris Williamson g->GCmemtrav += size;
563dfc11533SChris Williamson }
564dfc11533SChris Williamson
565dfc11533SChris Williamson
propagateall(global_State * g)566dfc11533SChris Williamson static void propagateall (global_State *g) {
567dfc11533SChris Williamson while (g->gray) propagatemark(g);
568dfc11533SChris Williamson }
569dfc11533SChris Williamson
570dfc11533SChris Williamson
propagatelist(global_State * g,GCObject * l)571dfc11533SChris Williamson static void propagatelist (global_State *g, GCObject *l) {
572dfc11533SChris Williamson lua_assert(g->gray == NULL); /* no grays left */
573dfc11533SChris Williamson g->gray = l;
574dfc11533SChris Williamson propagateall(g); /* traverse all elements from 'l' */
575dfc11533SChris Williamson }
576dfc11533SChris Williamson
577dfc11533SChris Williamson /*
578dfc11533SChris Williamson ** retraverse all gray lists. Because tables may be reinserted in other
579dfc11533SChris Williamson ** lists when traversed, traverse the original lists to avoid traversing
580dfc11533SChris Williamson ** twice the same table (which is not wrong, but inefficient)
581dfc11533SChris Williamson */
retraversegrays(global_State * g)582dfc11533SChris Williamson static void retraversegrays (global_State *g) {
583dfc11533SChris Williamson GCObject *weak = g->weak; /* save original lists */
584dfc11533SChris Williamson GCObject *grayagain = g->grayagain;
585dfc11533SChris Williamson GCObject *ephemeron = g->ephemeron;
586dfc11533SChris Williamson g->weak = g->grayagain = g->ephemeron = NULL;
587dfc11533SChris Williamson propagateall(g); /* traverse main gray list */
588dfc11533SChris Williamson propagatelist(g, grayagain);
589dfc11533SChris Williamson propagatelist(g, weak);
590dfc11533SChris Williamson propagatelist(g, ephemeron);
591dfc11533SChris Williamson }
592dfc11533SChris Williamson
593dfc11533SChris Williamson
convergeephemerons(global_State * g)594dfc11533SChris Williamson static void convergeephemerons (global_State *g) {
595dfc11533SChris Williamson int changed;
596dfc11533SChris Williamson do {
597dfc11533SChris Williamson GCObject *w;
598dfc11533SChris Williamson GCObject *next = g->ephemeron; /* get ephemeron list */
599dfc11533SChris Williamson g->ephemeron = NULL; /* tables will return to this list when traversed */
600dfc11533SChris Williamson changed = 0;
601dfc11533SChris Williamson while ((w = next) != NULL) {
602dfc11533SChris Williamson next = gco2t(w)->gclist;
603dfc11533SChris Williamson if (traverseephemeron(g, gco2t(w))) { /* traverse marked some value? */
604dfc11533SChris Williamson propagateall(g); /* propagate changes */
605dfc11533SChris Williamson changed = 1; /* will have to revisit all ephemeron tables */
606dfc11533SChris Williamson }
607dfc11533SChris Williamson }
608dfc11533SChris Williamson } while (changed);
609dfc11533SChris Williamson }
610dfc11533SChris Williamson
611dfc11533SChris Williamson /* }====================================================== */
612dfc11533SChris Williamson
613dfc11533SChris Williamson
614dfc11533SChris Williamson /*
615dfc11533SChris Williamson ** {======================================================
616dfc11533SChris Williamson ** Sweep Functions
617dfc11533SChris Williamson ** =======================================================
618dfc11533SChris Williamson */
619dfc11533SChris Williamson
620dfc11533SChris Williamson
621dfc11533SChris Williamson /*
622dfc11533SChris Williamson ** clear entries with unmarked keys from all weaktables in list 'l' up
623dfc11533SChris Williamson ** to element 'f'
624dfc11533SChris Williamson */
clearkeys(global_State * g,GCObject * l,GCObject * f)625dfc11533SChris Williamson static void clearkeys (global_State *g, GCObject *l, GCObject *f) {
626dfc11533SChris Williamson for (; l != f; l = gco2t(l)->gclist) {
627dfc11533SChris Williamson Table *h = gco2t(l);
628dfc11533SChris Williamson Node *n, *limit = gnodelast(h);
629dfc11533SChris Williamson for (n = gnode(h, 0); n < limit; n++) {
630dfc11533SChris Williamson if (!ttisnil(gval(n)) && (iscleared(g, gkey(n)))) {
631dfc11533SChris Williamson setnilvalue(gval(n)); /* remove value ... */
632dfc11533SChris Williamson removeentry(n); /* and remove entry from table */
633dfc11533SChris Williamson }
634dfc11533SChris Williamson }
635dfc11533SChris Williamson }
636dfc11533SChris Williamson }
637dfc11533SChris Williamson
638dfc11533SChris Williamson
639dfc11533SChris Williamson /*
640dfc11533SChris Williamson ** clear entries with unmarked values from all weaktables in list 'l' up
641dfc11533SChris Williamson ** to element 'f'
642dfc11533SChris Williamson */
clearvalues(global_State * g,GCObject * l,GCObject * f)643dfc11533SChris Williamson static void clearvalues (global_State *g, GCObject *l, GCObject *f) {
644dfc11533SChris Williamson for (; l != f; l = gco2t(l)->gclist) {
645dfc11533SChris Williamson Table *h = gco2t(l);
646dfc11533SChris Williamson Node *n, *limit = gnodelast(h);
647dfc11533SChris Williamson int i;
648dfc11533SChris Williamson for (i = 0; i < h->sizearray; i++) {
649dfc11533SChris Williamson TValue *o = &h->array[i];
650dfc11533SChris Williamson if (iscleared(g, o)) /* value was collected? */
651dfc11533SChris Williamson setnilvalue(o); /* remove value */
652dfc11533SChris Williamson }
653dfc11533SChris Williamson for (n = gnode(h, 0); n < limit; n++) {
654dfc11533SChris Williamson if (!ttisnil(gval(n)) && iscleared(g, gval(n))) {
655dfc11533SChris Williamson setnilvalue(gval(n)); /* remove value ... */
656dfc11533SChris Williamson removeentry(n); /* and remove entry from table */
657dfc11533SChris Williamson }
658dfc11533SChris Williamson }
659dfc11533SChris Williamson }
660dfc11533SChris Williamson }
661dfc11533SChris Williamson
662dfc11533SChris Williamson
freeobj(lua_State * L,GCObject * o)663dfc11533SChris Williamson static void freeobj (lua_State *L, GCObject *o) {
664dfc11533SChris Williamson switch (gch(o)->tt) {
665dfc11533SChris Williamson case LUA_TPROTO: luaF_freeproto(L, gco2p(o)); break;
666dfc11533SChris Williamson case LUA_TLCL: {
667dfc11533SChris Williamson luaM_freemem(L, o, sizeLclosure(gco2lcl(o)->nupvalues));
668dfc11533SChris Williamson break;
669dfc11533SChris Williamson }
670dfc11533SChris Williamson case LUA_TCCL: {
671dfc11533SChris Williamson luaM_freemem(L, o, sizeCclosure(gco2ccl(o)->nupvalues));
672dfc11533SChris Williamson break;
673dfc11533SChris Williamson }
674dfc11533SChris Williamson case LUA_TUPVAL: luaF_freeupval(L, gco2uv(o)); break;
675dfc11533SChris Williamson case LUA_TTABLE: luaH_free(L, gco2t(o)); break;
676dfc11533SChris Williamson case LUA_TTHREAD: luaE_freethread(L, gco2th(o)); break;
677dfc11533SChris Williamson case LUA_TUSERDATA: luaM_freemem(L, o, sizeudata(gco2u(o))); break;
678dfc11533SChris Williamson case LUA_TSHRSTR:
679dfc11533SChris Williamson G(L)->strt.nuse--;
680*46ac8fdfSToomas Soome /* FALLTHROUGH */
681dfc11533SChris Williamson case LUA_TLNGSTR: {
682dfc11533SChris Williamson luaM_freemem(L, o, sizestring(gco2ts(o)));
683dfc11533SChris Williamson break;
684dfc11533SChris Williamson }
685dfc11533SChris Williamson default: lua_assert(0);
686dfc11533SChris Williamson }
687dfc11533SChris Williamson }
688dfc11533SChris Williamson
689dfc11533SChris Williamson
690dfc11533SChris Williamson #define sweepwholelist(L,p) sweeplist(L,p,MAX_LUMEM)
691dfc11533SChris Williamson static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count);
692dfc11533SChris Williamson
693dfc11533SChris Williamson
694dfc11533SChris Williamson /*
695dfc11533SChris Williamson ** sweep the (open) upvalues of a thread and resize its stack and
696dfc11533SChris Williamson ** list of call-info structures.
697dfc11533SChris Williamson */
sweepthread(lua_State * L,lua_State * L1)698dfc11533SChris Williamson static void sweepthread (lua_State *L, lua_State *L1) {
699dfc11533SChris Williamson if (L1->stack == NULL) return; /* stack not completely built yet */
700dfc11533SChris Williamson sweepwholelist(L, &L1->openupval); /* sweep open upvalues */
701dfc11533SChris Williamson luaE_freeCI(L1); /* free extra CallInfo slots */
702dfc11533SChris Williamson /* should not change the stack during an emergency gc cycle */
703dfc11533SChris Williamson if (G(L)->gckind != KGC_EMERGENCY)
704dfc11533SChris Williamson luaD_shrinkstack(L1);
705dfc11533SChris Williamson }
706dfc11533SChris Williamson
707dfc11533SChris Williamson
708dfc11533SChris Williamson /*
709dfc11533SChris Williamson ** sweep at most 'count' elements from a list of GCObjects erasing dead
710dfc11533SChris Williamson ** objects, where a dead (not alive) object is one marked with the "old"
711dfc11533SChris Williamson ** (non current) white and not fixed.
712dfc11533SChris Williamson ** In non-generational mode, change all non-dead objects back to white,
713dfc11533SChris Williamson ** preparing for next collection cycle.
714dfc11533SChris Williamson ** In generational mode, keep black objects black, and also mark them as
715dfc11533SChris Williamson ** old; stop when hitting an old object, as all objects after that
716dfc11533SChris Williamson ** one will be old too.
717dfc11533SChris Williamson ** When object is a thread, sweep its list of open upvalues too.
718dfc11533SChris Williamson */
sweeplist(lua_State * L,GCObject ** p,lu_mem count)719dfc11533SChris Williamson static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
720dfc11533SChris Williamson global_State *g = G(L);
721dfc11533SChris Williamson int ow = otherwhite(g);
722dfc11533SChris Williamson int toclear, toset; /* bits to clear and to set in all live objects */
723dfc11533SChris Williamson int tostop; /* stop sweep when this is true */
724dfc11533SChris Williamson if (isgenerational(g)) { /* generational mode? */
725dfc11533SChris Williamson toclear = ~0; /* clear nothing */
726dfc11533SChris Williamson toset = bitmask(OLDBIT); /* set the old bit of all surviving objects */
727dfc11533SChris Williamson tostop = bitmask(OLDBIT); /* do not sweep old generation */
728dfc11533SChris Williamson }
729dfc11533SChris Williamson else { /* normal mode */
730dfc11533SChris Williamson toclear = maskcolors; /* clear all color bits + old bit */
731dfc11533SChris Williamson toset = luaC_white(g); /* make object white */
732dfc11533SChris Williamson tostop = 0; /* do not stop */
733dfc11533SChris Williamson }
734dfc11533SChris Williamson while (*p != NULL && count-- > 0) {
735dfc11533SChris Williamson GCObject *curr = *p;
736dfc11533SChris Williamson int marked = gch(curr)->marked;
737dfc11533SChris Williamson if (isdeadm(ow, marked)) { /* is 'curr' dead? */
738dfc11533SChris Williamson *p = gch(curr)->next; /* remove 'curr' from list */
739dfc11533SChris Williamson freeobj(L, curr); /* erase 'curr' */
740dfc11533SChris Williamson }
741dfc11533SChris Williamson else {
742dfc11533SChris Williamson if (testbits(marked, tostop))
743dfc11533SChris Williamson return NULL; /* stop sweeping this list */
744dfc11533SChris Williamson if (gch(curr)->tt == LUA_TTHREAD)
745dfc11533SChris Williamson sweepthread(L, gco2th(curr)); /* sweep thread's upvalues */
746dfc11533SChris Williamson /* update marks */
747dfc11533SChris Williamson gch(curr)->marked = cast_byte((marked & toclear) | toset);
748dfc11533SChris Williamson p = &gch(curr)->next; /* go to next element */
749dfc11533SChris Williamson }
750dfc11533SChris Williamson }
751dfc11533SChris Williamson return (*p == NULL) ? NULL : p;
752dfc11533SChris Williamson }
753dfc11533SChris Williamson
754dfc11533SChris Williamson
755dfc11533SChris Williamson /*
756dfc11533SChris Williamson ** sweep a list until a live object (or end of list)
757dfc11533SChris Williamson */
sweeptolive(lua_State * L,GCObject ** p,int * n)758dfc11533SChris Williamson static GCObject **sweeptolive (lua_State *L, GCObject **p, int *n) {
759dfc11533SChris Williamson GCObject ** old = p;
760dfc11533SChris Williamson int i = 0;
761dfc11533SChris Williamson do {
762dfc11533SChris Williamson i++;
763dfc11533SChris Williamson p = sweeplist(L, p, 1);
764dfc11533SChris Williamson } while (p == old);
765dfc11533SChris Williamson if (n) *n += i;
766dfc11533SChris Williamson return p;
767dfc11533SChris Williamson }
768dfc11533SChris Williamson
769dfc11533SChris Williamson /* }====================================================== */
770dfc11533SChris Williamson
771dfc11533SChris Williamson
772dfc11533SChris Williamson /*
773dfc11533SChris Williamson ** {======================================================
774dfc11533SChris Williamson ** Finalization
775dfc11533SChris Williamson ** =======================================================
776dfc11533SChris Williamson */
777dfc11533SChris Williamson
checkSizes(lua_State * L)778dfc11533SChris Williamson static void checkSizes (lua_State *L) {
779dfc11533SChris Williamson global_State *g = G(L);
780dfc11533SChris Williamson if (g->gckind != KGC_EMERGENCY) { /* do not change sizes in emergency */
781dfc11533SChris Williamson int hs = g->strt.size / 2; /* half the size of the string table */
782dfc11533SChris Williamson if (g->strt.nuse < cast(lu_int32, hs)) /* using less than that half? */
783dfc11533SChris Williamson luaS_resize(L, hs); /* halve its size */
784dfc11533SChris Williamson luaZ_freebuffer(L, &g->buff); /* free concatenation buffer */
785dfc11533SChris Williamson }
786dfc11533SChris Williamson }
787dfc11533SChris Williamson
788dfc11533SChris Williamson
udata2finalize(global_State * g)789dfc11533SChris Williamson static GCObject *udata2finalize (global_State *g) {
790dfc11533SChris Williamson GCObject *o = g->tobefnz; /* get first element */
791dfc11533SChris Williamson lua_assert(isfinalized(o));
792dfc11533SChris Williamson g->tobefnz = gch(o)->next; /* remove it from 'tobefnz' list */
793dfc11533SChris Williamson gch(o)->next = g->allgc; /* return it to 'allgc' list */
794dfc11533SChris Williamson g->allgc = o;
795dfc11533SChris Williamson resetbit(gch(o)->marked, SEPARATED); /* mark that it is not in 'tobefnz' */
796dfc11533SChris Williamson lua_assert(!isold(o)); /* see MOVE OLD rule */
797dfc11533SChris Williamson if (!keepinvariantout(g)) /* not keeping invariant? */
798dfc11533SChris Williamson makewhite(g, o); /* "sweep" object */
799dfc11533SChris Williamson return o;
800dfc11533SChris Williamson }
801dfc11533SChris Williamson
802dfc11533SChris Williamson
dothecall(lua_State * L,void * ud)803dfc11533SChris Williamson static void dothecall (lua_State *L, void *ud) {
804dfc11533SChris Williamson UNUSED(ud);
805dfc11533SChris Williamson luaD_call(L, L->top - 2, 0, 0);
806dfc11533SChris Williamson }
807dfc11533SChris Williamson
808dfc11533SChris Williamson
GCTM(lua_State * L,int propagateerrors)809dfc11533SChris Williamson static void GCTM (lua_State *L, int propagateerrors) {
810dfc11533SChris Williamson global_State *g = G(L);
811dfc11533SChris Williamson const TValue *tm;
812dfc11533SChris Williamson TValue v;
813dfc11533SChris Williamson setgcovalue(L, &v, udata2finalize(g));
814dfc11533SChris Williamson tm = luaT_gettmbyobj(L, &v, TM_GC);
815dfc11533SChris Williamson if (tm != NULL && ttisfunction(tm)) { /* is there a finalizer? */
816dfc11533SChris Williamson int status;
817dfc11533SChris Williamson lu_byte oldah = L->allowhook;
818dfc11533SChris Williamson int running = g->gcrunning;
819dfc11533SChris Williamson L->allowhook = 0; /* stop debug hooks during GC metamethod */
820dfc11533SChris Williamson g->gcrunning = 0; /* avoid GC steps */
821dfc11533SChris Williamson setobj2s(L, L->top, tm); /* push finalizer... */
822dfc11533SChris Williamson setobj2s(L, L->top + 1, &v); /* ... and its argument */
823dfc11533SChris Williamson L->top += 2; /* and (next line) call the finalizer */
824dfc11533SChris Williamson status = luaD_pcall(L, dothecall, NULL, savestack(L, L->top - 2), 0);
825dfc11533SChris Williamson L->allowhook = oldah; /* restore hooks */
826dfc11533SChris Williamson g->gcrunning = running; /* restore state */
827dfc11533SChris Williamson if (status != LUA_OK && propagateerrors) { /* error while running __gc? */
828dfc11533SChris Williamson if (status == LUA_ERRRUN) { /* is there an error object? */
829dfc11533SChris Williamson const char *msg = (ttisstring(L->top - 1))
830dfc11533SChris Williamson ? svalue(L->top - 1)
831dfc11533SChris Williamson : "no message";
832dfc11533SChris Williamson luaO_pushfstring(L, "error in __gc metamethod (%s)", msg);
833dfc11533SChris Williamson status = LUA_ERRGCMM; /* error in __gc metamethod */
834dfc11533SChris Williamson }
835dfc11533SChris Williamson luaD_throw(L, status); /* re-throw error */
836dfc11533SChris Williamson }
837dfc11533SChris Williamson }
838dfc11533SChris Williamson }
839dfc11533SChris Williamson
840dfc11533SChris Williamson
841dfc11533SChris Williamson /*
842dfc11533SChris Williamson ** move all unreachable objects (or 'all' objects) that need
843dfc11533SChris Williamson ** finalization from list 'finobj' to list 'tobefnz' (to be finalized)
844dfc11533SChris Williamson */
separatetobefnz(lua_State * L,int all)845dfc11533SChris Williamson static void separatetobefnz (lua_State *L, int all) {
846dfc11533SChris Williamson global_State *g = G(L);
847dfc11533SChris Williamson GCObject **p = &g->finobj;
848dfc11533SChris Williamson GCObject *curr;
849dfc11533SChris Williamson GCObject **lastnext = &g->tobefnz;
850dfc11533SChris Williamson /* find last 'next' field in 'tobefnz' list (to add elements in its end) */
851dfc11533SChris Williamson while (*lastnext != NULL)
852dfc11533SChris Williamson lastnext = &gch(*lastnext)->next;
853dfc11533SChris Williamson while ((curr = *p) != NULL) { /* traverse all finalizable objects */
854dfc11533SChris Williamson lua_assert(!isfinalized(curr));
855dfc11533SChris Williamson lua_assert(testbit(gch(curr)->marked, SEPARATED));
856dfc11533SChris Williamson if (!(iswhite(curr) || all)) /* not being collected? */
857dfc11533SChris Williamson p = &gch(curr)->next; /* don't bother with it */
858dfc11533SChris Williamson else {
859dfc11533SChris Williamson l_setbit(gch(curr)->marked, FINALIZEDBIT); /* won't be finalized again */
860dfc11533SChris Williamson *p = gch(curr)->next; /* remove 'curr' from 'finobj' list */
861dfc11533SChris Williamson gch(curr)->next = *lastnext; /* link at the end of 'tobefnz' list */
862dfc11533SChris Williamson *lastnext = curr;
863dfc11533SChris Williamson lastnext = &gch(curr)->next;
864dfc11533SChris Williamson }
865dfc11533SChris Williamson }
866dfc11533SChris Williamson }
867dfc11533SChris Williamson
868dfc11533SChris Williamson
869dfc11533SChris Williamson /*
870dfc11533SChris Williamson ** if object 'o' has a finalizer, remove it from 'allgc' list (must
871dfc11533SChris Williamson ** search the list to find it) and link it in 'finobj' list.
872dfc11533SChris Williamson */
luaC_checkfinalizer(lua_State * L,GCObject * o,Table * mt)873dfc11533SChris Williamson void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
874dfc11533SChris Williamson global_State *g = G(L);
875dfc11533SChris Williamson if (testbit(gch(o)->marked, SEPARATED) || /* obj. is already separated... */
876dfc11533SChris Williamson isfinalized(o) || /* ... or is finalized... */
877dfc11533SChris Williamson gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
878dfc11533SChris Williamson return; /* nothing to be done */
879dfc11533SChris Williamson else { /* move 'o' to 'finobj' list */
880dfc11533SChris Williamson GCObject **p;
881dfc11533SChris Williamson GCheader *ho = gch(o);
882dfc11533SChris Williamson if (g->sweepgc == &ho->next) { /* avoid removing current sweep object */
883dfc11533SChris Williamson lua_assert(issweepphase(g));
884dfc11533SChris Williamson g->sweepgc = sweeptolive(L, g->sweepgc, NULL);
885dfc11533SChris Williamson }
886dfc11533SChris Williamson /* search for pointer pointing to 'o' */
887dfc11533SChris Williamson for (p = &g->allgc; *p != o; p = &gch(*p)->next) { /* empty */ }
888dfc11533SChris Williamson *p = ho->next; /* remove 'o' from root list */
889dfc11533SChris Williamson ho->next = g->finobj; /* link it in list 'finobj' */
890dfc11533SChris Williamson g->finobj = o;
891dfc11533SChris Williamson l_setbit(ho->marked, SEPARATED); /* mark it as such */
892dfc11533SChris Williamson if (!keepinvariantout(g)) /* not keeping invariant? */
893dfc11533SChris Williamson makewhite(g, o); /* "sweep" object */
894dfc11533SChris Williamson else
895dfc11533SChris Williamson resetoldbit(o); /* see MOVE OLD rule */
896dfc11533SChris Williamson }
897dfc11533SChris Williamson }
898dfc11533SChris Williamson
899dfc11533SChris Williamson /* }====================================================== */
900dfc11533SChris Williamson
901dfc11533SChris Williamson
902dfc11533SChris Williamson /*
903dfc11533SChris Williamson ** {======================================================
904dfc11533SChris Williamson ** GC control
905dfc11533SChris Williamson ** =======================================================
906dfc11533SChris Williamson */
907dfc11533SChris Williamson
908dfc11533SChris Williamson
909dfc11533SChris Williamson /*
910dfc11533SChris Williamson ** set a reasonable "time" to wait before starting a new GC cycle;
911dfc11533SChris Williamson ** cycle will start when memory use hits threshold
912dfc11533SChris Williamson */
setpause(global_State * g,l_mem estimate)913dfc11533SChris Williamson static void setpause (global_State *g, l_mem estimate) {
914dfc11533SChris Williamson l_mem debt, threshold;
915dfc11533SChris Williamson estimate = estimate / PAUSEADJ; /* adjust 'estimate' */
916dfc11533SChris Williamson threshold = (g->gcpause < MAX_LMEM / estimate) /* overflow? */
917dfc11533SChris Williamson ? estimate * g->gcpause /* no overflow */
918dfc11533SChris Williamson : MAX_LMEM; /* overflow; truncate to maximum */
919dfc11533SChris Williamson debt = -cast(l_mem, threshold - gettotalbytes(g));
920dfc11533SChris Williamson luaE_setdebt(g, debt);
921dfc11533SChris Williamson }
922dfc11533SChris Williamson
923dfc11533SChris Williamson
924dfc11533SChris Williamson #define sweepphases \
925dfc11533SChris Williamson (bitmask(GCSsweepstring) | bitmask(GCSsweepudata) | bitmask(GCSsweep))
926dfc11533SChris Williamson
927dfc11533SChris Williamson
928dfc11533SChris Williamson /*
929dfc11533SChris Williamson ** enter first sweep phase (strings) and prepare pointers for other
930dfc11533SChris Williamson ** sweep phases. The calls to 'sweeptolive' make pointers point to an
931dfc11533SChris Williamson ** object inside the list (instead of to the header), so that the real
932dfc11533SChris Williamson ** sweep do not need to skip objects created between "now" and the start
933dfc11533SChris Williamson ** of the real sweep.
934dfc11533SChris Williamson ** Returns how many objects it swept.
935dfc11533SChris Williamson */
entersweep(lua_State * L)936dfc11533SChris Williamson static int entersweep (lua_State *L) {
937dfc11533SChris Williamson global_State *g = G(L);
938dfc11533SChris Williamson int n = 0;
939dfc11533SChris Williamson g->gcstate = GCSsweepstring;
940dfc11533SChris Williamson lua_assert(g->sweepgc == NULL && g->sweepfin == NULL);
941dfc11533SChris Williamson /* prepare to sweep strings, finalizable objects, and regular objects */
942dfc11533SChris Williamson g->sweepstrgc = 0;
943dfc11533SChris Williamson g->sweepfin = sweeptolive(L, &g->finobj, &n);
944dfc11533SChris Williamson g->sweepgc = sweeptolive(L, &g->allgc, &n);
945dfc11533SChris Williamson return n;
946dfc11533SChris Williamson }
947dfc11533SChris Williamson
948dfc11533SChris Williamson
949dfc11533SChris Williamson /*
950dfc11533SChris Williamson ** change GC mode
951dfc11533SChris Williamson */
luaC_changemode(lua_State * L,int mode)952dfc11533SChris Williamson void luaC_changemode (lua_State *L, int mode) {
953dfc11533SChris Williamson global_State *g = G(L);
954dfc11533SChris Williamson if (mode == g->gckind) return; /* nothing to change */
955dfc11533SChris Williamson if (mode == KGC_GEN) { /* change to generational mode */
956dfc11533SChris Williamson /* make sure gray lists are consistent */
957dfc11533SChris Williamson luaC_runtilstate(L, bitmask(GCSpropagate));
958dfc11533SChris Williamson g->GCestimate = gettotalbytes(g);
959dfc11533SChris Williamson g->gckind = KGC_GEN;
960dfc11533SChris Williamson }
961dfc11533SChris Williamson else { /* change to incremental mode */
962dfc11533SChris Williamson /* sweep all objects to turn them back to white
963dfc11533SChris Williamson (as white has not changed, nothing extra will be collected) */
964dfc11533SChris Williamson g->gckind = KGC_NORMAL;
965dfc11533SChris Williamson entersweep(L);
966dfc11533SChris Williamson luaC_runtilstate(L, ~sweepphases);
967dfc11533SChris Williamson }
968dfc11533SChris Williamson }
969dfc11533SChris Williamson
970dfc11533SChris Williamson
971dfc11533SChris Williamson /*
972dfc11533SChris Williamson ** call all pending finalizers
973dfc11533SChris Williamson */
callallpendingfinalizers(lua_State * L,int propagateerrors)974dfc11533SChris Williamson static void callallpendingfinalizers (lua_State *L, int propagateerrors) {
975dfc11533SChris Williamson global_State *g = G(L);
976dfc11533SChris Williamson while (g->tobefnz) {
977dfc11533SChris Williamson resetoldbit(g->tobefnz);
978dfc11533SChris Williamson GCTM(L, propagateerrors);
979dfc11533SChris Williamson }
980dfc11533SChris Williamson }
981dfc11533SChris Williamson
982dfc11533SChris Williamson
luaC_freeallobjects(lua_State * L)983dfc11533SChris Williamson void luaC_freeallobjects (lua_State *L) {
984dfc11533SChris Williamson global_State *g = G(L);
985dfc11533SChris Williamson int i;
986dfc11533SChris Williamson separatetobefnz(L, 1); /* separate all objects with finalizers */
987dfc11533SChris Williamson lua_assert(g->finobj == NULL);
988dfc11533SChris Williamson callallpendingfinalizers(L, 0);
989dfc11533SChris Williamson g->currentwhite = WHITEBITS; /* this "white" makes all objects look dead */
990dfc11533SChris Williamson g->gckind = KGC_NORMAL;
991dfc11533SChris Williamson sweepwholelist(L, &g->finobj); /* finalizers can create objs. in 'finobj' */
992dfc11533SChris Williamson sweepwholelist(L, &g->allgc);
993dfc11533SChris Williamson for (i = 0; i < g->strt.size; i++) /* free all string lists */
994dfc11533SChris Williamson sweepwholelist(L, &g->strt.hash[i]);
995dfc11533SChris Williamson lua_assert(g->strt.nuse == 0);
996dfc11533SChris Williamson }
997dfc11533SChris Williamson
998dfc11533SChris Williamson
atomic(lua_State * L)999dfc11533SChris Williamson static l_mem atomic (lua_State *L) {
1000dfc11533SChris Williamson global_State *g = G(L);
1001dfc11533SChris Williamson l_mem work = -cast(l_mem, g->GCmemtrav); /* start counting work */
1002dfc11533SChris Williamson GCObject *origweak, *origall;
1003dfc11533SChris Williamson lua_assert(!iswhite(obj2gco(g->mainthread)));
1004dfc11533SChris Williamson markobject(g, L); /* mark running thread */
1005dfc11533SChris Williamson /* registry and global metatables may be changed by API */
1006dfc11533SChris Williamson markvalue(g, &g->l_registry);
1007dfc11533SChris Williamson markmt(g); /* mark basic metatables */
1008dfc11533SChris Williamson /* remark occasional upvalues of (maybe) dead threads */
1009dfc11533SChris Williamson remarkupvals(g);
1010dfc11533SChris Williamson propagateall(g); /* propagate changes */
1011dfc11533SChris Williamson work += g->GCmemtrav; /* stop counting (do not (re)count grays) */
1012dfc11533SChris Williamson /* traverse objects caught by write barrier and by 'remarkupvals' */
1013dfc11533SChris Williamson retraversegrays(g);
1014dfc11533SChris Williamson work -= g->GCmemtrav; /* restart counting */
1015dfc11533SChris Williamson convergeephemerons(g);
1016dfc11533SChris Williamson /* at this point, all strongly accessible objects are marked. */
1017dfc11533SChris Williamson /* clear values from weak tables, before checking finalizers */
1018dfc11533SChris Williamson clearvalues(g, g->weak, NULL);
1019dfc11533SChris Williamson clearvalues(g, g->allweak, NULL);
1020dfc11533SChris Williamson origweak = g->weak; origall = g->allweak;
1021dfc11533SChris Williamson work += g->GCmemtrav; /* stop counting (objects being finalized) */
1022dfc11533SChris Williamson separatetobefnz(L, 0); /* separate objects to be finalized */
1023dfc11533SChris Williamson markbeingfnz(g); /* mark objects that will be finalized */
1024dfc11533SChris Williamson propagateall(g); /* remark, to propagate `preserveness' */
1025dfc11533SChris Williamson work -= g->GCmemtrav; /* restart counting */
1026dfc11533SChris Williamson convergeephemerons(g);
1027dfc11533SChris Williamson /* at this point, all resurrected objects are marked. */
1028dfc11533SChris Williamson /* remove dead objects from weak tables */
1029dfc11533SChris Williamson clearkeys(g, g->ephemeron, NULL); /* clear keys from all ephemeron tables */
1030dfc11533SChris Williamson clearkeys(g, g->allweak, NULL); /* clear keys from all allweak tables */
1031dfc11533SChris Williamson /* clear values from resurrected weak tables */
1032dfc11533SChris Williamson clearvalues(g, g->weak, origweak);
1033dfc11533SChris Williamson clearvalues(g, g->allweak, origall);
1034dfc11533SChris Williamson g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */
1035dfc11533SChris Williamson work += g->GCmemtrav; /* complete counting */
1036dfc11533SChris Williamson return work; /* estimate of memory marked by 'atomic' */
1037dfc11533SChris Williamson }
1038dfc11533SChris Williamson
1039dfc11533SChris Williamson
singlestep(lua_State * L)1040dfc11533SChris Williamson static lu_mem singlestep (lua_State *L) {
1041dfc11533SChris Williamson global_State *g = G(L);
1042dfc11533SChris Williamson switch (g->gcstate) {
1043dfc11533SChris Williamson case GCSpause: {
1044dfc11533SChris Williamson /* start to count memory traversed */
1045dfc11533SChris Williamson g->GCmemtrav = g->strt.size * sizeof(GCObject*);
1046dfc11533SChris Williamson lua_assert(!isgenerational(g));
1047dfc11533SChris Williamson restartcollection(g);
1048dfc11533SChris Williamson g->gcstate = GCSpropagate;
1049dfc11533SChris Williamson return g->GCmemtrav;
1050dfc11533SChris Williamson }
1051dfc11533SChris Williamson case GCSpropagate: {
1052dfc11533SChris Williamson if (g->gray) {
1053dfc11533SChris Williamson lu_mem oldtrav = g->GCmemtrav;
1054dfc11533SChris Williamson propagatemark(g);
1055dfc11533SChris Williamson return g->GCmemtrav - oldtrav; /* memory traversed in this step */
1056dfc11533SChris Williamson }
1057dfc11533SChris Williamson else { /* no more `gray' objects */
1058dfc11533SChris Williamson lu_mem work;
1059dfc11533SChris Williamson int sw;
1060dfc11533SChris Williamson g->gcstate = GCSatomic; /* finish mark phase */
1061dfc11533SChris Williamson g->GCestimate = g->GCmemtrav; /* save what was counted */;
1062dfc11533SChris Williamson work = atomic(L); /* add what was traversed by 'atomic' */
1063dfc11533SChris Williamson g->GCestimate += work; /* estimate of total memory traversed */
1064dfc11533SChris Williamson sw = entersweep(L);
1065dfc11533SChris Williamson return work + sw * GCSWEEPCOST;
1066dfc11533SChris Williamson }
1067dfc11533SChris Williamson }
1068dfc11533SChris Williamson case GCSsweepstring: {
1069dfc11533SChris Williamson int i;
1070dfc11533SChris Williamson for (i = 0; i < GCSWEEPMAX && g->sweepstrgc + i < g->strt.size; i++)
1071dfc11533SChris Williamson sweepwholelist(L, &g->strt.hash[g->sweepstrgc + i]);
1072dfc11533SChris Williamson g->sweepstrgc += i;
1073dfc11533SChris Williamson if (g->sweepstrgc >= g->strt.size) /* no more strings to sweep? */
1074dfc11533SChris Williamson g->gcstate = GCSsweepudata;
1075dfc11533SChris Williamson return i * GCSWEEPCOST;
1076dfc11533SChris Williamson }
1077dfc11533SChris Williamson case GCSsweepudata: {
1078dfc11533SChris Williamson if (g->sweepfin) {
1079dfc11533SChris Williamson g->sweepfin = sweeplist(L, g->sweepfin, GCSWEEPMAX);
1080dfc11533SChris Williamson return GCSWEEPMAX*GCSWEEPCOST;
1081dfc11533SChris Williamson }
1082dfc11533SChris Williamson else {
1083dfc11533SChris Williamson g->gcstate = GCSsweep;
1084dfc11533SChris Williamson return 0;
1085dfc11533SChris Williamson }
1086dfc11533SChris Williamson }
1087dfc11533SChris Williamson case GCSsweep: {
1088dfc11533SChris Williamson if (g->sweepgc) {
1089dfc11533SChris Williamson g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
1090dfc11533SChris Williamson return GCSWEEPMAX*GCSWEEPCOST;
1091dfc11533SChris Williamson }
1092dfc11533SChris Williamson else {
1093dfc11533SChris Williamson /* sweep main thread */
1094dfc11533SChris Williamson GCObject *mt = obj2gco(g->mainthread);
1095dfc11533SChris Williamson sweeplist(L, &mt, 1);
1096dfc11533SChris Williamson checkSizes(L);
1097dfc11533SChris Williamson g->gcstate = GCSpause; /* finish collection */
1098dfc11533SChris Williamson return GCSWEEPCOST;
1099dfc11533SChris Williamson }
1100dfc11533SChris Williamson }
1101dfc11533SChris Williamson default: lua_assert(0); return 0;
1102dfc11533SChris Williamson }
1103dfc11533SChris Williamson }
1104dfc11533SChris Williamson
1105dfc11533SChris Williamson
1106dfc11533SChris Williamson /*
1107dfc11533SChris Williamson ** advances the garbage collector until it reaches a state allowed
1108dfc11533SChris Williamson ** by 'statemask'
1109dfc11533SChris Williamson */
luaC_runtilstate(lua_State * L,int statesmask)1110dfc11533SChris Williamson void luaC_runtilstate (lua_State *L, int statesmask) {
1111dfc11533SChris Williamson global_State *g = G(L);
1112dfc11533SChris Williamson while (!testbit(statesmask, g->gcstate))
1113dfc11533SChris Williamson singlestep(L);
1114dfc11533SChris Williamson }
1115dfc11533SChris Williamson
1116dfc11533SChris Williamson
generationalcollection(lua_State * L)1117dfc11533SChris Williamson static void generationalcollection (lua_State *L) {
1118dfc11533SChris Williamson global_State *g = G(L);
1119dfc11533SChris Williamson lua_assert(g->gcstate == GCSpropagate);
1120dfc11533SChris Williamson if (g->GCestimate == 0) { /* signal for another major collection? */
1121dfc11533SChris Williamson luaC_fullgc(L, 0); /* perform a full regular collection */
1122dfc11533SChris Williamson g->GCestimate = gettotalbytes(g); /* update control */
1123dfc11533SChris Williamson }
1124dfc11533SChris Williamson else {
1125dfc11533SChris Williamson lu_mem estimate = g->GCestimate;
1126dfc11533SChris Williamson luaC_runtilstate(L, bitmask(GCSpause)); /* run complete (minor) cycle */
1127dfc11533SChris Williamson g->gcstate = GCSpropagate; /* skip restart */
1128dfc11533SChris Williamson if (gettotalbytes(g) > (estimate / 100) * g->gcmajorinc)
1129dfc11533SChris Williamson g->GCestimate = 0; /* signal for a major collection */
1130dfc11533SChris Williamson else
1131dfc11533SChris Williamson g->GCestimate = estimate; /* keep estimate from last major coll. */
1132dfc11533SChris Williamson
1133dfc11533SChris Williamson }
1134dfc11533SChris Williamson setpause(g, gettotalbytes(g));
1135dfc11533SChris Williamson lua_assert(g->gcstate == GCSpropagate);
1136dfc11533SChris Williamson }
1137dfc11533SChris Williamson
1138dfc11533SChris Williamson
incstep(lua_State * L)1139dfc11533SChris Williamson static void incstep (lua_State *L) {
1140dfc11533SChris Williamson global_State *g = G(L);
1141dfc11533SChris Williamson l_mem debt = g->GCdebt;
1142dfc11533SChris Williamson int stepmul = g->gcstepmul;
1143dfc11533SChris Williamson if (stepmul < 40) stepmul = 40; /* avoid ridiculous low values (and 0) */
1144dfc11533SChris Williamson /* convert debt from Kb to 'work units' (avoid zero debt and overflows) */
1145dfc11533SChris Williamson debt = (debt / STEPMULADJ) + 1;
1146dfc11533SChris Williamson debt = (debt < MAX_LMEM / stepmul) ? debt * stepmul : MAX_LMEM;
1147dfc11533SChris Williamson do { /* always perform at least one single step */
1148dfc11533SChris Williamson lu_mem work = singlestep(L); /* do some work */
1149dfc11533SChris Williamson debt -= work;
1150dfc11533SChris Williamson } while (debt > -GCSTEPSIZE && g->gcstate != GCSpause);
1151dfc11533SChris Williamson if (g->gcstate == GCSpause)
1152dfc11533SChris Williamson setpause(g, g->GCestimate); /* pause until next cycle */
1153dfc11533SChris Williamson else {
1154dfc11533SChris Williamson debt = (debt / stepmul) * STEPMULADJ; /* convert 'work units' to Kb */
1155dfc11533SChris Williamson luaE_setdebt(g, debt);
1156dfc11533SChris Williamson }
1157dfc11533SChris Williamson }
1158dfc11533SChris Williamson
1159dfc11533SChris Williamson
1160dfc11533SChris Williamson /*
1161dfc11533SChris Williamson ** performs a basic GC step
1162dfc11533SChris Williamson */
luaC_forcestep(lua_State * L)1163dfc11533SChris Williamson void luaC_forcestep (lua_State *L) {
1164dfc11533SChris Williamson global_State *g = G(L);
1165dfc11533SChris Williamson int i;
1166dfc11533SChris Williamson if (isgenerational(g)) generationalcollection(L);
1167dfc11533SChris Williamson else incstep(L);
1168dfc11533SChris Williamson /* run a few finalizers (or all of them at the end of a collect cycle) */
1169dfc11533SChris Williamson for (i = 0; g->tobefnz && (i < GCFINALIZENUM || g->gcstate == GCSpause); i++)
1170dfc11533SChris Williamson GCTM(L, 1); /* call one finalizer */
1171dfc11533SChris Williamson }
1172dfc11533SChris Williamson
1173dfc11533SChris Williamson
1174dfc11533SChris Williamson /*
1175dfc11533SChris Williamson ** performs a basic GC step only if collector is running
1176dfc11533SChris Williamson */
luaC_step(lua_State * L)1177dfc11533SChris Williamson void luaC_step (lua_State *L) {
1178dfc11533SChris Williamson global_State *g = G(L);
1179dfc11533SChris Williamson if (g->gcrunning) luaC_forcestep(L);
1180dfc11533SChris Williamson else luaE_setdebt(g, -GCSTEPSIZE); /* avoid being called too often */
1181dfc11533SChris Williamson }
1182dfc11533SChris Williamson
1183dfc11533SChris Williamson
1184dfc11533SChris Williamson
1185dfc11533SChris Williamson /*
1186dfc11533SChris Williamson ** performs a full GC cycle; if "isemergency", does not call
1187dfc11533SChris Williamson ** finalizers (which could change stack positions)
1188dfc11533SChris Williamson */
luaC_fullgc(lua_State * L,int isemergency)1189dfc11533SChris Williamson void luaC_fullgc (lua_State *L, int isemergency) {
1190dfc11533SChris Williamson global_State *g = G(L);
1191dfc11533SChris Williamson int origkind = g->gckind;
1192dfc11533SChris Williamson lua_assert(origkind != KGC_EMERGENCY);
1193dfc11533SChris Williamson if (isemergency) /* do not run finalizers during emergency GC */
1194dfc11533SChris Williamson g->gckind = KGC_EMERGENCY;
1195dfc11533SChris Williamson else {
1196dfc11533SChris Williamson g->gckind = KGC_NORMAL;
1197dfc11533SChris Williamson callallpendingfinalizers(L, 1);
1198dfc11533SChris Williamson }
1199dfc11533SChris Williamson if (keepinvariant(g)) { /* may there be some black objects? */
1200dfc11533SChris Williamson /* must sweep all objects to turn them back to white
1201dfc11533SChris Williamson (as white has not changed, nothing will be collected) */
1202dfc11533SChris Williamson entersweep(L);
1203dfc11533SChris Williamson }
1204dfc11533SChris Williamson /* finish any pending sweep phase to start a new cycle */
1205dfc11533SChris Williamson luaC_runtilstate(L, bitmask(GCSpause));
1206dfc11533SChris Williamson luaC_runtilstate(L, ~bitmask(GCSpause)); /* start new collection */
1207dfc11533SChris Williamson luaC_runtilstate(L, bitmask(GCSpause)); /* run entire collection */
1208dfc11533SChris Williamson if (origkind == KGC_GEN) { /* generational mode? */
1209dfc11533SChris Williamson /* generational mode must be kept in propagate phase */
1210dfc11533SChris Williamson luaC_runtilstate(L, bitmask(GCSpropagate));
1211dfc11533SChris Williamson }
1212dfc11533SChris Williamson g->gckind = origkind;
1213dfc11533SChris Williamson setpause(g, gettotalbytes(g));
1214dfc11533SChris Williamson if (!isemergency) /* do not run finalizers during emergency GC */
1215dfc11533SChris Williamson callallpendingfinalizers(L, 1);
1216dfc11533SChris Williamson }
1217dfc11533SChris Williamson
1218dfc11533SChris Williamson /* }====================================================== */
1219dfc11533SChris Williamson
1220dfc11533SChris Williamson
1221