commit ed9be5e1f0d4b68aa848f85744ad959d7a57c9f4
parent 9d801f43d47967a533b399352fab63c4a62ffae7
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 11 Dec 2001 14:52:35 -0200
reentrant implementation of garbage collection
Diffstat:
3 files changed, 31 insertions(+), 25 deletions(-)
diff --git a/lgc.c b/lgc.c
@@ -136,6 +136,8 @@ static void markudet (lua_State *L, GCState *st) {
Udata *u;
for (u = G(L)->rootudata; u; u = u->uv.next)
marktable(st, u->uv.eventtable);
+ for (u = G(L)->tmudata; u; u = u->uv.next)
+ marktable(st, u->uv.eventtable);
}
@@ -290,27 +292,30 @@ static void collecttable (lua_State *L) {
}
-static Udata *collectudata (lua_State *L, int keep) {
+static void collectudata (lua_State *L) {
Udata **p = &G(L)->rootudata;
Udata *curr;
- Udata *collected = NULL;
+ Udata *collected = NULL; /* to collect udata with gc event */
+ Udata **lastcollected = &collected;
while ((curr = *p) != NULL) {
if (isudmarked(curr)) {
unmarkud(curr);
p = &curr->uv.next;
}
- else { /* collect */
- const TObject *tm = fasttm(L, curr->uv.eventtable, TM_GC);
+ else {
*p = curr->uv.next;
- if (keep || tm != NULL) {
- curr->uv.next = collected;
- collected = curr;
+ if (fasttm(L, curr->uv.eventtable, TM_GC) != NULL) { /* gc event? */
+ curr->uv.next = NULL; /* link `curr' at the end of `collected' list */
+ *lastcollected = curr;
+ lastcollected = &curr->uv.next;
}
- else /* no gc action; delete udata */
+ else /* no gc event; delete udata */
luaM_free(L, curr, sizeudata(curr->uv.len));
}
}
- return collected;
+ /* insert collected udata with gc event into `tmudata' list */
+ *lastcollected = G(L)->tmudata;
+ G(L)->tmudata = collected;
}
@@ -365,12 +370,12 @@ static void callgcTM (lua_State *L, Udata *udata) {
}
-static void callgcTMudata (lua_State *L, Udata *c) {
+static void callgcTMudata (lua_State *L) {
luaD_checkstack(L, 3);
L->top++; /* reserve space to keep udata while runs its gc method */
- while (c != NULL) {
- Udata *udata = c;
- c = udata->uv.next; /* remove udata from list */
+ while (G(L)->tmudata != NULL) {
+ Udata *udata = G(L)->tmudata;
+ G(L)->tmudata = udata->uv.next; /* remove udata from list */
udata->uv.next = G(L)->rootudata; /* resurect it */
G(L)->rootudata = udata;
setuvalue(L->top - 1, udata);
@@ -383,34 +388,32 @@ static void callgcTMudata (lua_State *L, Udata *c) {
void luaC_callallgcTM (lua_State *L) {
- if (G(L)->rootudata) { /* avoid problems with incomplete states */
- Udata *c = collectudata(L, 1); /* collect all udata */
- callgcTMudata(L, c); /* call their GC tag methods */
- }
+ lua_assert(G(L)->tmudata == NULL);
+ G(L)->tmudata = G(L)->rootudata; /* all udata must be collected */
+ G(L)->rootudata = NULL;
+ callgcTMudata(L); /* call their GC tag methods */
}
-Udata *luaC_collect (lua_State *L, int all) {
- Udata *c = collectudata(L, 0);
+void luaC_collect (lua_State *L, int all) {
+ collectudata(L);
collectstrings(L, all);
collecttable(L);
collectproto(L);
collectupval(L);
collectclosures(L);
- return c;
}
void luaC_collectgarbage (lua_State *L) {
- Udata *c;
GCState st;
st.tmark = NULL;
st.toclear = NULL;
markall(L, &st);
cleartables(st.toclear);
- c = luaC_collect(L, 0);
+ luaC_collect(L, 0);
checkMbuffer(L);
G(L)->GCthreshold = 2*G(L)->nblocks; /* new threshold */
- callgcTMudata(L, c);
+ callgcTMudata(L);
}
diff --git a/lstate.c b/lstate.c
@@ -59,8 +59,9 @@ static void f_luaopen (lua_State *L, void *ud) {
G(L)->rootproto = NULL;
G(L)->rootcl = NULL;
G(L)->roottable = NULL;
- G(L)->rootudata = NULL;
G(L)->rootupval = NULL;
+ G(L)->rootudata = NULL;
+ G(L)->tmudata = NULL;
G(L)->nblocks = sizeof(lua_State) + sizeof(global_State);
luaD_init(L, so->stacksize); /* init stack */
/* create default event table with a dummy table, and then close the loop */
@@ -118,6 +119,7 @@ static void close_state (lua_State *L, lua_State *OL) {
else if (G(L)) { /* last thread; close global state */
if (G(L)->rootudata) /* (avoid problems with incomplete states) */
luaC_callallgcTM(L); /* call GC tag methods for all udata */
+ lua_assert(G(L)->tmudata == NULL);
luaC_collect(L, 1); /* collect all elements */
lua_assert(G(L)->rootproto == NULL);
lua_assert(G(L)->rootudata == NULL);
diff --git a/lstate.h b/lstate.h
@@ -81,8 +81,9 @@ typedef struct global_State {
Proto *rootproto; /* list of all prototypes */
Closure *rootcl; /* list of all closures */
Table *roottable; /* list of all tables */
- Udata *rootudata; /* list of all userdata */
UpVal *rootupval; /* list of closed up values */
+ Udata *rootudata; /* list of all userdata */
+ Udata *tmudata; /* list of userdata to be GC */
TString *tmname[TM_N]; /* array with tag-method names */
} global_State;