commit 74123e96869bdb55d3967036e2bc0c6f9e0550d6
parent 9c196bebad4f84ffb43f0ef1e19792cc4b795704
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 22 Mar 2010 15:27:39 -0300
draft version of a generational mode for garbage collection. (Not well
tested; no major collections; ...)
Diffstat:
5 files changed, 70 insertions(+), 35 deletions(-)
diff --git a/lapi.c b/lapi.c
@@ -1,5 +1,5 @@
/*
-** $Id: lapi.c,v 2.113 2010/02/09 11:55:37 roberto Exp roberto $
+** $Id: lapi.c,v 2.114 2010/03/08 16:55:52 roberto Exp roberto $
** Lua API
** See Copyright Notice in lua.h
*/
@@ -928,6 +928,7 @@ LUA_API int lua_gc (lua_State *L, int what, int data) {
break;
}
case LUA_GCRESTART: {
+ g->gckind = KGC_NORMAL;
g->GCthreshold = g->totalbytes;
break;
}
@@ -973,6 +974,11 @@ LUA_API int lua_gc (lua_State *L, int what, int data) {
res = (g->GCthreshold != MAX_LUMEM);
break;
}
+ case LUA_GCGEN: { /* change collector to generational mode */
+ luaC_runtilstate(L, bitmask(GCSpropagate));
+ g->gckind = KGC_GEN;
+ break;
+ }
default: res = -1; /* invalid option */
}
lua_unlock(L);
diff --git a/lbaselib.c b/lbaselib.c
@@ -1,5 +1,5 @@
/*
-** $Id: lbaselib.c,v 1.237 2010/03/13 03:57:46 roberto Exp roberto $
+** $Id: lbaselib.c,v 1.238 2010/03/19 15:52:48 roberto Exp roberto $
** Basic library
** See Copyright Notice in lua.h
*/
@@ -186,10 +186,10 @@ static int luaB_gcinfo (lua_State *L) {
static int luaB_collectgarbage (lua_State *L) {
static const char *const opts[] = {"stop", "restart", "collect",
- "count", "step", "setpause", "setstepmul", "isrunning", NULL};
+ "count", "step", "setpause", "setstepmul", "isrunning", "gen", NULL};
static const int optsnum[] = {LUA_GCSTOP, LUA_GCRESTART, LUA_GCCOLLECT,
LUA_GCCOUNT, LUA_GCSTEP, LUA_GCSETPAUSE, LUA_GCSETSTEPMUL,
- LUA_GCISRUNNING};
+ LUA_GCISRUNNING, LUA_GCGEN};
int o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
int ex = luaL_optint(L, 2, 0);
int res = lua_gc(L, o, ex);
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.66 2009/12/16 16:42:58 roberto Exp roberto $
+** $Id: lgc.c,v 2.67 2009/12/22 15:32:50 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -29,7 +29,7 @@
#define GCFINALIZECOST 100
-#define maskcolors cast_byte(~(bitmask(BLACKBIT)|WHITEBITS))
+#define maskcolors (~(bitmask(BLACKBIT)|WHITEBITS))
#define makewhite(g,x) \
(gch(x)->marked = cast_byte((gch(x)->marked & maskcolors) | luaC_white(g)))
@@ -95,10 +95,10 @@ static int iscleared (const TValue *o, int iskey) {
void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v) {
global_State *g = G(L);
lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
- lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
+ lua_assert(g->gckind == KGC_GEN ||
+ (g->gcstate != GCSfinalize && g->gcstate != GCSpause));
lua_assert(gch(o)->tt != LUA_TTABLE);
- /* must keep invariant? */
- if (g->gcstate == GCSpropagate)
+ if (g->gcstate == GCSpropagate) /* must keep invariant? */
reallymarkobject(g, v); /* restore invariant */
else /* don't mind */
makewhite(g, o); /* mark as white just to avoid other barriers */
@@ -109,7 +109,8 @@ void luaC_barrierback (lua_State *L, Table *t) {
global_State *g = G(L);
GCObject *o = obj2gco(t);
lua_assert(isblack(o) && !isdead(g, o));
- lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
+ lua_assert(g->gckind == KGC_GEN ||
+ (g->gcstate != GCSfinalize && g->gcstate != GCSpause));
black2gray(o); /* make table gray (again) */
t->gclist = g->grayagain;
g->grayagain = o;
@@ -234,7 +235,6 @@ static void markroot (lua_State *L) {
markvalue(g, &g->l_registry);
markmt(g);
markbeingfnz(g); /* mark any finalizing object left from previous cycle */
- g->gcstate = GCSpropagate;
}
@@ -401,8 +401,9 @@ static void traversestack (global_State *g, lua_State *L) {
/*
-** traverse one gray object, turning it to black.
-** Returns `quantity' traversed.
+** traverse one gray object, turning it to black (except for threads,
+** which are always gray).
+** Returns 'quantity' traversed.
*/
static l_mem propagatemark (global_State *g) {
GCObject *o = g->gray;
@@ -547,13 +548,16 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
GCObject *curr;
global_State *g = G(L);
int deadmask = otherwhite(g);
+ int gckind = g->gckind;
while ((curr = *p) != NULL && count-- > 0) {
int alive = (gch(curr)->marked ^ WHITEBITS) & deadmask;
if (gch(curr)->tt == LUA_TTHREAD)
sweepthread(L, gco2th(curr), alive);
if (alive) {
lua_assert(!isdead(g, curr) || testbit(gch(curr)->marked, FIXEDBIT));
- makewhite(g, curr); /* make it white (for next cycle) */
+ /* in generational mode all live objects are kept black, which
+ means they grow to old generation */
+ if (gckind != KGC_GEN) makewhite(g, curr);
p = &gch(curr)->next;
}
else { /* must erase `curr' */
@@ -700,7 +704,6 @@ void luaC_freeallobjects (lua_State *L) {
static void atomic (lua_State *L) {
global_State *g = G(L);
- g->gcstate = GCSatomic;
lua_assert(!iswhite(obj2gco(g->mainthread)));
markobject(g, L); /* mark running thread */
/* registry and global metatables may be changed by API */
@@ -725,8 +728,7 @@ static void atomic (lua_State *L) {
cleartable(g->ephemeron);
cleartable(g->allweak);
g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */
- g->sweepstrgc = 0; /* go to sweep phase */
- g->gcstate = GCSsweepstring;
+ g->sweepstrgc = 0; /* prepare sweep phase */
}
@@ -736,13 +738,16 @@ static l_mem singlestep (lua_State *L) {
switch (g->gcstate) {
case GCSpause: {
markroot(L); /* start a new collection */
+ g->gcstate = GCSpropagate;
return 0;
}
case GCSpropagate: {
if (g->gray)
return propagatemark(g);
else { /* no more `gray' objects */
- atomic(L); /* finish mark phase */
+ g->gcstate = GCSatomic; /* finish mark phase */
+ atomic(L);
+ g->gcstate = GCSsweepstring;
return 0;
}
}
@@ -776,7 +781,33 @@ static l_mem singlestep (lua_State *L) {
}
-void luaC_step (lua_State *L) {
+/*
+** advances the garbage collector until it reaches a state allowed
+** by 'statemask'
+*/
+void luaC_runtilstate (lua_State *L, int statesmask) {
+ global_State *g = G(L);
+ while (!testbit(statesmask, g->gcstate))
+ singlestep(L);
+}
+
+
+static void generationalcollection (lua_State *L) {
+static int c = 0;
+static int prev = 0;
+ global_State *g = G(L);
+int a = g->totalbytes;
+ lua_assert(g->gcstate == GCSpropagate);
+ luaC_runtilstate(L, bitmask(GCSpause));
+ g->gcstate = GCSpropagate; /* do not run 'markroot' */
+ g->GCthreshold = (g->totalbytes/100) * g->gcpause;
+/*printf("count: %d old: %d new: %d dif: %d\n", c++, a, g->totalbytes,
+g->totalbytes - prev);*/
+prev = g->totalbytes;
+}
+
+
+static void step (lua_State *L) {
global_State *g = G(L);
l_mem lim = (GCSTEPSIZE/100) * g->gcstepmul; /* how much to work */
lu_mem debt = g->totalbytes - g->GCthreshold;
@@ -792,14 +823,9 @@ void luaC_step (lua_State *L) {
}
-/*
-** advances the garbage collector until it reaches a state allowed
-** by 'statemask'
-*/
-void luaC_runtilstate (lua_State *L, int statesmask) {
- global_State *g = G(L);
- while (!testbit(statesmask, g->gcstate))
- singlestep(L);
+void luaC_step (lua_State *L) {
+ if (G(L)->gckind == KGC_GEN) generationalcollection(L);
+ else step(L);
}
@@ -809,7 +835,8 @@ void luaC_runtilstate (lua_State *L, int statesmask) {
*/
void luaC_fullgc (lua_State *L, int isemergency) {
global_State *g = G(L);
- lua_assert(g->gckind == KGC_NORMAL);
+ int origkind = g->gckind;
+ lua_assert(origkind == KGC_NORMAL || origkind == KGC_GEN);
g->gckind = isemergency ? KGC_EMERGENCY : KGC_FORCED;
if (g->gcstate == GCSpropagate) { /* marking phase? */
/* must sweep all objects to turn them back to white
@@ -819,12 +846,12 @@ void luaC_fullgc (lua_State *L, int isemergency) {
}
/* finish any pending sweep phase */
luaC_runtilstate(L, ~bit2mask(GCSsweepstring, GCSsweep));
- markroot(L); /* start a new collection */
+ g->gcstate = GCSpause; /* start a new collection */
/* run collector up to finalizers */
luaC_runtilstate(L, bitmask(GCSfinalize));
- g->gckind = KGC_NORMAL;
+ g->gckind = origkind;
if (!isemergency) /* do not run finalizers during emergency GC */
- luaC_runtilstate(L, ~bitmask(GCSfinalize));
+ luaC_runtilstate(L, bitmask(GCSpause));
g->GCthreshold = (g->totalbytes/100) * g->gcpause;
}
diff --git a/lstate.h b/lstate.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.h,v 2.53 2010/02/09 11:55:37 roberto Exp roberto $
+** $Id: lstate.h,v 2.54 2010/03/13 15:55:42 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -58,6 +58,7 @@ struct lua_longjmp; /* defined in ldo.c */
#define KGC_NORMAL 0
#define KGC_FORCED 1 /* gc was forced by the program */
#define KGC_EMERGENCY 2 /* gc was forced by an allocation failure */
+#define KGC_GEN 3 /* generational collection */
typedef struct stringtable {
@@ -142,9 +143,9 @@ typedef struct global_State {
struct lua_State *mainthread;
UpVal uvhead; /* head of double-linked list of all open upvalues */
const lua_Number *version; /* pointer to version number */
- struct Table *mt[NUM_TAGS]; /* metatables for basic types */
- TString *tmname[TM_N]; /* array with tag-method names */
TString *envn; /* environment variable name */
+ TString *tmname[TM_N]; /* array with tag-method names */
+ struct Table *mt[NUM_TAGS]; /* metatables for basic types */
} global_State;
diff --git a/lua.h b/lua.h
@@ -1,5 +1,5 @@
/*
-** $Id: lua.h,v 1.262 2010/03/13 03:57:46 roberto Exp roberto $
+** $Id: lua.h,v 1.263 2010/03/19 21:04:17 roberto Exp roberto $
** Lua - A Scripting Language
** Lua.org, PUC-Rio, Brazil (http://www.lua.org)
** See Copyright Notice at the end of this file
@@ -267,6 +267,7 @@ LUA_API int (lua_status) (lua_State *L);
#define LUA_GCSETPAUSE 6
#define LUA_GCSETSTEPMUL 7
#define LUA_GCISRUNNING 8
+#define LUA_GCGEN 9
LUA_API int (lua_gc) (lua_State *L, int what, int data);
