ref: 1018d7a7091fd5e0433f501a3474cdc3fec322cc
dir: /libinterp/gc.c/
#include "lib9.h" #include "interp.h" #include "pool.h" enum { Quanta = 50, /* Allocated blocks to sweep each time slice usually */ MaxQuanta = 15*Quanta, PTRHASH = (1<<5) }; static int quanta = Quanta; static int gce, gct = 1; typedef struct Ptrhash Ptrhash; struct Ptrhash { Heap *value; Ptrhash *next; }; int nprop; int gchalt; int mflag; int mutator = 0; int gccolor = 3; ulong gcnruns; ulong gcsweeps; ulong gcbroken; ulong gchalted; ulong gcepochs; uvlong gcdestroys; uvlong gcinspects; static int marker = 1; static int sweeper = 2; static Bhdr* base; static Bhdr* limit; Bhdr* ptr; static int visit; extern Pool* heapmem; static Ptrhash *ptrtab[PTRHASH]; static Ptrhash *ptrfree; #define HASHPTR(p) (((ulong)(p) >> 6) & (PTRHASH - 1)) void ptradd(Heap *v) { int h; Ptrhash *p; if ((p = ptrfree) != nil) ptrfree = p->next; else if ((p = malloc(sizeof (Ptrhash))) == nil) error("ptradd malloc"); h = HASHPTR(v); p->value = v; p->next = ptrtab[h]; ptrtab[h] = p; } void ptrdel(Heap *v) { Ptrhash *p, **l; for (l = &ptrtab[HASHPTR(v)]; (p = *l) != nil; l = &p->next) { if (p->value == v) { *l = p->next; p->next = ptrfree; ptrfree = p; return; } } /* ptradd must have failed */ } static void ptrmark(void) { int i; Heap *h; Ptrhash *p; for (i = 0; i < PTRHASH; i++) { for (p = ptrtab[i]; p != nil; p = p->next) { h = p->value; Setmark(h); } } } void noptrs(Type *t, void *vw) { USED(t); USED(vw); } static int markdepth; /* code simpler with a depth search compared to a width search*/ void markheap(Type *t, void *vw) { Heap *h; uchar *p; int i, c, m; WORD **w, **q; Type *t1; if(t == nil || t->np == 0) return; markdepth++; w = (WORD**)vw; p = t->map; for(i = 0; i < t->np; i++) { c = *p++; if(c != 0) { q = w; for(m = 0x80; m != 0; m >>= 1) { if((c & m) && *q != H) { h = D2H(*q); Setmark(h); if(h->color == propagator && --visit >= 0 && markdepth < 64){ gce--; h->color = mutator; if((t1 = h->t) != nil) t1->mark(t1, H2D(void*, h)); } } q++; } } w += 8; } markdepth--; } /* * This routine should be modified to be incremental, but how? */ void markarray(Type *t, void *vw) { int i; Heap *h; uchar *v; Array *a; USED(t); a = vw; t = a->t; if(a->root != H) { h = D2H(a->root); Setmark(h); } if(t->np == 0) return; v = a->data; for(i = 0; i < a->len; i++) { markheap(t, v); v += t->size; } visit -= a->len; } void marklist(Type *t, void *vw) { List *l; Heap *h; USED(t); l = vw; markheap(l->t, l->data); while(visit > 0) { l = l->tail; if(l == H) return; h = D2H(l); Setmark(h); markheap(l->t, l->data); visit--; } l = l->tail; if(l != H) { D2H(l)->color = propagator; nprop = 1; } } static void rootset(Prog *root) { Heap *h; Type *t; Frame *f; Module *m; Stkext *sx; Modlink *ml; uchar *fp, *sp, *ex, *mp; mutator = gccolor % 3; marker = (gccolor-1)%3; sweeper = (gccolor-2)%3; while(root != nil) { ml = root->R.M; h = D2H(ml); Setmark(h); mp = ml->MP; if(mp != H) { h = D2H(mp); Setmark(h); } sp = root->R.SP; ex = root->R.EX; while(ex != nil) { sx = (Stkext*)ex; fp = sx->reg.tos.fu; while(fp != sp) { f = (Frame*)fp; t = f->t; if(t == nil) t = sx->reg.TR; fp += t->size; t->mark(t, f); ml = f->mr; if(ml != nil) { h = D2H(ml); Setmark(h); mp = ml->MP; if(mp != H) { h = D2H(mp); Setmark(h); } } } ex = sx->reg.EX; sp = sx->reg.SP; } root = root->next; } for(m = modules; m != nil; m = m->link) { if(m->origmp != H) { h = D2H(m->origmp); Setmark(h); } } ptrmark(); } static int okbhdr(Bhdr *b) { if(b == nil) return 0; switch(b->magic) { case MAGIC_A: case MAGIC_F: case MAGIC_E: case MAGIC_I: return 1; } return 0; } static void domflag(Heap *h) { int i; Module *m; print("sweep h=0x%lux t=0x%lux c=%d", (ulong)h, (ulong)h->t, h->color); for(m = modules; m != nil; m = m->link) { for(i = 0; i < m->ntype; i++) { if(m->type[i] == h->t) { print(" module %s desc %d", m->name, i); break; } } } print("\n"); if(mflag > 1) abort(); } void rungc(Prog *p) { Type *t; Heap *h; Bhdr *b; gcnruns++; if(gchalt) { gchalted++; return; } if(base == nil) { gcsweeps++; b = poolchain(heapmem); base = b; ptr = b; limit = B2LIMIT(b); } /* Chain broken ? */ if(!okbhdr(ptr)) { base = nil; gcbroken++; return; } for(visit = quanta; visit > 0; ) { if(ptr->magic == MAGIC_A) { visit--; gct++; gcinspects++; h = B2D(ptr); t = h->t; if(h->color == propagator) { gce--; h->color = mutator; if(t != nil) t->mark(t, H2D(void*, h)); } else if(h->color == sweeper) { gce++; if(0 && mflag) domflag(h); if(heapmonitor != nil) heapmonitor(2, h, 0); if(t != nil) { gclock(); t->free(h, 1); gcunlock(); freetype(t); } gcdestroys++; poolfree(heapmem, h); } } ptr = B2NB(ptr); if(ptr >= limit) { base = base->clink; if(base == nil) break; ptr = base; limit = B2LIMIT(base); } } quanta = (MaxQuanta+Quanta)/2 + ((MaxQuanta-Quanta)/20)*((100*gce)/gct); if(quanta < Quanta) quanta = Quanta; if(quanta > MaxQuanta) quanta = MaxQuanta; if(base != nil) /* Completed this iteration ? */ return; if(nprop == 0) { /* Completed the epoch ? */ gcepochs++; gccolor++; rootset(p); gce = 0; gct = 1; return; } nprop = 0; }