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