commit f356d5acdd9d8e8f7e9d1d7632c4657f945ff4f4
parent 76953316d1283ab6324b59b914ef53a521408444
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 23 Nov 2022 17:16:53 -0300
First version of GC counting objects for control
Still needs to review generational mode.
Diffstat:
9 files changed, 162 insertions(+), 156 deletions(-)
diff --git a/lapi.c b/lapi.c
@@ -1154,11 +1154,11 @@ LUA_API int lua_gc (lua_State *L, int what, ...) {
}
case LUA_GCCOUNT: {
/* GC values are expressed in Kbytes: #bytes/2^10 */
- res = cast_int(gettotalbytes(g) >> 10);
+ res = cast_int(g->totalbytes >> 10);
break;
}
case LUA_GCCOUNTB: {
- res = cast_int(gettotalbytes(g) & 0x3ff);
+ res = cast_int(g->totalbytes & 0x3ff);
break;
}
case LUA_GCSTEP: {
@@ -1171,7 +1171,7 @@ LUA_API int lua_gc (lua_State *L, int what, ...) {
luaC_step(L);
}
else { /* add 'data' to total debt */
- debt = cast(l_mem, data) * 1024 + g->GCdebt;
+ debt = data + g->GCdebt;
luaE_setdebt(g, debt);
luaC_checkGC(L);
}
@@ -1217,7 +1217,8 @@ LUA_API int lua_gc (lua_State *L, int what, ...) {
if (stepmul != 0)
setgcparam(g->gcstepmul, stepmul);
if (stepsize != 0)
- g->gcstepsize = stepsize;
+ g->gcstepsize = (stepsize <= log2maxs(l_mem)) ? stepsize
+ : log2maxs(l_mem);
luaC_changemode(L, KGC_INC);
break;
}
diff --git a/lgc.c b/lgc.c
@@ -19,6 +19,7 @@
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
+#include "llex.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
@@ -32,7 +33,7 @@
** (Large enough to dissipate fixed overheads but small enough
** to allow small steps for the collector.)
*/
-#define GCSWEEPMAX 100
+#define GCSWEEPMAX 20
/*
** Maximum number of finalizers to call in each single step.
@@ -46,19 +47,6 @@
#define GCFINALIZECOST 50
-/*
-** The equivalent, in bytes, of one unit of "work" (visiting a slot,
-** sweeping an object, etc.)
-*/
-#define WORK2MEM sizeof(TValue)
-
-
-/*
-** macro to adjust 'pause': 'pause' is actually used like
-** 'pause / PAUSEADJ' (value chosen by tests)
-*/
-#define PAUSEADJ 100
-
/* mask with all color bits */
#define maskcolors (bitmask(BLACKBIT) | WHITEBITS)
@@ -105,7 +93,7 @@
#define markobjectN(g,t) { if (t) markobject(g,t); }
static void reallymarkobject (global_State *g, GCObject *o);
-static lu_mem atomic (lua_State *L);
+static l_mem atomic (lua_State *L);
static void entersweep (lua_State *L);
@@ -259,7 +247,7 @@ GCObject *luaC_newobjdt (lua_State *L, int tt, size_t sz, size_t offset) {
global_State *g = G(L);
char *p = cast_charp(luaM_newobject(L, novariant(tt), sz));
GCObject *o = cast(GCObject *, p + offset);
- g->totalobjs++;
+ g->GCdebt++;
o->marked = luaC_white(g);
o->tt = tt;
o->next = g->allgc;
@@ -268,6 +256,9 @@ GCObject *luaC_newobjdt (lua_State *L, int tt, size_t sz, size_t offset) {
}
+/*
+** create a new collectable object with no offset.
+*/
GCObject *luaC_newobj (lua_State *L, int tt, size_t sz) {
return luaC_newobjdt(L, tt, sz, 0);
}
@@ -296,6 +287,7 @@ GCObject *luaC_newobj (lua_State *L, int tt, size_t sz) {
** (only closures can), and a userdata's metatable must be a table.
*/
static void reallymarkobject (global_State *g, GCObject *o) {
+ g->marked++;
switch (o->tt) {
case LUA_VSHRSTR:
case LUA_VLNGSTR: {
@@ -343,9 +335,9 @@ static void markmt (global_State *g) {
/*
** mark all objects in list of being-finalized
*/
-static lu_mem markbeingfnz (global_State *g) {
+static l_mem markbeingfnz (global_State *g) {
GCObject *o;
- lu_mem count = 0;
+ l_mem count = 0;
for (o = g->tobefnz; o != NULL; o = o->next) {
count++;
markobject(g, o);
@@ -365,12 +357,11 @@ static lu_mem markbeingfnz (global_State *g) {
** upvalues, as they have nothing to be checked. (If the thread gets an
** upvalue later, it will be linked in the list again.)
*/
-static int remarkupvals (global_State *g) {
+static l_mem remarkupvals (global_State *g) {
+ l_mem work = 0;
lua_State *thread;
lua_State **p = &g->twups;
- int work = 0; /* estimate of how much work was done here */
while ((thread = *p) != NULL) {
- work++;
if (!iswhite(thread) && thread->openupval != NULL)
p = &thread->twups; /* keep marked thread with upvalues in the list */
else { /* thread is not marked or without upvalues */
@@ -380,13 +371,13 @@ static int remarkupvals (global_State *g) {
thread->twups = thread; /* mark that it is out of list */
for (uv = thread->openupval; uv != NULL; uv = uv->u.open.next) {
lua_assert(getage(uv) <= getage(thread));
- work++;
if (!iswhite(uv)) { /* upvalue already visited? */
lua_assert(upisopen(uv) && isgray(uv));
markvalue(g, uv->v.p); /* mark its value */
}
}
}
+ work++;
}
return work;
}
@@ -399,10 +390,15 @@ static void cleargraylists (global_State *g) {
/*
-** mark root set and reset all gray lists, to start a new collection
+** mark root set and reset all gray lists, to start a new collection.
+** 'marked' is initialized with the number of fixed objects in the state,
+** to count the total number of live objects during a cycle. (That is
+** the metafield names, plus the reserved words, plus "_ENV" plus the
+** memory-error message.)
*/
static void restartcollection (global_State *g) {
cleargraylists(g);
+ g->marked = TM_N + NUM_RESERVED + 2;
markobject(g, g->mainthread);
markvalue(g, &g->l_registry);
markmt(g);
@@ -540,7 +536,7 @@ static void traversestrongtable (global_State *g, Table *h) {
}
-static lu_mem traversetable (global_State *g, Table *h) {
+static void traversetable (global_State *g, Table *h) {
const char *weakkey, *weakvalue;
const TValue *mode = gfasttm(g, h->metatable, TM_MODE);
markobjectN(g, h->metatable);
@@ -557,17 +553,15 @@ static lu_mem traversetable (global_State *g, Table *h) {
}
else /* not weak */
traversestrongtable(g, h);
- return 1 + h->alimit + 2 * allocsizenode(h);
}
-static int traverseudata (global_State *g, Udata *u) {
+static void traverseudata (global_State *g, Udata *u) {
int i;
markobjectN(g, u->metatable); /* mark its metatable */
for (i = 0; i < u->nuvalue; i++)
markvalue(g, &u->uv[i].uv);
genlink(g, obj2gco(u));
- return 1 + u->nuvalue;
}
@@ -576,7 +570,7 @@ static int traverseudata (global_State *g, Udata *u) {
** arrays can be larger than needed; the extra slots are filled with
** NULL, so the use of 'markobjectN')
*/
-static int traverseproto (global_State *g, Proto *f) {
+static void traverseproto (global_State *g, Proto *f) {
int i;
markobjectN(g, f->source);
for (i = 0; i < f->sizek; i++) /* mark literals */
@@ -587,29 +581,26 @@ static int traverseproto (global_State *g, Proto *f) {
markobjectN(g, f->p[i]);
for (i = 0; i < f->sizelocvars; i++) /* mark local-variable names */
markobjectN(g, f->locvars[i].varname);
- return 1 + f->sizek + f->sizeupvalues + f->sizep + f->sizelocvars;
}
-static int traverseCclosure (global_State *g, CClosure *cl) {
+static void traverseCclosure (global_State *g, CClosure *cl) {
int i;
for (i = 0; i < cl->nupvalues; i++) /* mark its upvalues */
markvalue(g, &cl->upvalue[i]);
- return 1 + cl->nupvalues;
}
/*
** Traverse a Lua closure, marking its prototype and its upvalues.
** (Both can be NULL while closure is being created.)
*/
-static int traverseLclosure (global_State *g, LClosure *cl) {
+static void traverseLclosure (global_State *g, LClosure *cl) {
int i;
markobjectN(g, cl->p); /* mark its prototype */
for (i = 0; i < cl->nupvalues; i++) { /* visit its upvalues */
UpVal *uv = cl->upvals[i];
markobjectN(g, uv); /* mark upvalue */
}
- return 1 + cl->nupvalues;
}
@@ -625,13 +616,13 @@ static int traverseLclosure (global_State *g, LClosure *cl) {
** (which can only happen in generational mode) or if the traverse is in
** the propagate phase (which can only happen in incremental mode).
*/
-static int traversethread (global_State *g, lua_State *th) {
+static void traversethread (global_State *g, lua_State *th) {
UpVal *uv;
StkId o = th->stack.p;
if (isold(th) || g->gcstate == GCSpropagate)
linkgclist(th, g->grayagain); /* insert into 'grayagain' list */
if (o == NULL)
- return 1; /* stack not completely built yet */
+ return; /* stack not completely built yet */
lua_assert(g->gcstate == GCSatomic ||
th->openupval == NULL || isintwups(th));
for (; o < th->top.p; o++) /* mark live elements in the stack */
@@ -649,34 +640,35 @@ static int traversethread (global_State *g, lua_State *th) {
}
else if (!g->gcemergency)
luaD_shrinkstack(th); /* do not change stack in emergency cycle */
- return 1 + stacksize(th);
}
/*
** traverse one gray object, turning it to black.
*/
-static lu_mem propagatemark (global_State *g) {
+static void propagatemark (global_State *g) {
GCObject *o = g->gray;
nw2black(o);
g->gray = *getgclist(o); /* remove from 'gray' list */
switch (o->tt) {
- case LUA_VTABLE: return traversetable(g, gco2t(o));
- case LUA_VUSERDATA: return traverseudata(g, gco2u(o));
- case LUA_VLCL: return traverseLclosure(g, gco2lcl(o));
- case LUA_VCCL: return traverseCclosure(g, gco2ccl(o));
- case LUA_VPROTO: return traverseproto(g, gco2p(o));
- case LUA_VTHREAD: return traversethread(g, gco2th(o));
- default: lua_assert(0); return 0;
+ case LUA_VTABLE: traversetable(g, gco2t(o)); break;
+ case LUA_VUSERDATA: traverseudata(g, gco2u(o)); break;
+ case LUA_VLCL: traverseLclosure(g, gco2lcl(o)); break;
+ case LUA_VCCL: traverseCclosure(g, gco2ccl(o)); break;
+ case LUA_VPROTO: traverseproto(g, gco2p(o)); break;
+ case LUA_VTHREAD: traversethread(g, gco2th(o)); break;
+ default: lua_assert(0);
}
}
-static lu_mem propagateall (global_State *g) {
- lu_mem tot = 0;
- while (g->gray)
- tot += propagatemark(g);
- return tot;
+static l_mem propagateall (global_State *g) {
+ l_mem work = 0;
+ while (g->gray) {
+ propagatemark(g);
+ work++;
+ }
+ return work;
}
@@ -685,10 +677,10 @@ static lu_mem propagateall (global_State *g) {
** Repeat until it converges, that is, nothing new is marked. 'dir'
** inverts the direction of the traversals, trying to speed up
** convergence on chains in the same table.
-**
*/
-static void convergeephemerons (global_State *g) {
+static l_mem convergeephemerons (global_State *g) {
int changed;
+ l_mem work = 0;
int dir = 0;
do {
GCObject *w;
@@ -703,9 +695,11 @@ static void convergeephemerons (global_State *g) {
propagateall(g); /* propagate changes */
changed = 1; /* will have to revisit all ephemeron tables */
}
+ work++;
}
dir = !dir; /* invert direction next time */
} while (changed); /* repeat until no more changes */
+ return work;
}
/* }====================================================== */
@@ -721,7 +715,8 @@ static void convergeephemerons (global_State *g) {
/*
** clear entries with unmarked keys from all weaktables in list 'l'
*/
-static void clearbykeys (global_State *g, GCObject *l) {
+static l_mem clearbykeys (global_State *g, GCObject *l) {
+ l_mem work = 0;
for (; l; l = gco2t(l)->gclist) {
Table *h = gco2t(l);
Node *limit = gnodelast(h);
@@ -732,7 +727,9 @@ static void clearbykeys (global_State *g, GCObject *l) {
if (isempty(gval(n))) /* is entry empty? */
clearkey(n); /* clear its key */
}
+ work++;
}
+ return work;
}
@@ -740,7 +737,8 @@ static void clearbykeys (global_State *g, GCObject *l) {
** clear entries with unmarked values from all weaktables in list 'l' up
** to element 'f'
*/
-static void clearbyvalues (global_State *g, GCObject *l, GCObject *f) {
+static l_mem clearbyvalues (global_State *g, GCObject *l, GCObject *f) {
+ l_mem work = 0;
for (; l != f; l = gco2t(l)->gclist) {
Table *h = gco2t(l);
Node *n, *limit = gnodelast(h);
@@ -757,7 +755,9 @@ static void clearbyvalues (global_State *g, GCObject *l, GCObject *f) {
if (isempty(gval(n))) /* is entry empty? */
clearkey(n); /* clear its key */
}
+ work++;
}
+ return work;
}
@@ -819,10 +819,9 @@ static void freeobj (lua_State *L, GCObject *o) {
** objects, where a dead object is one marked with the old (non current)
** white; change all non-dead objects back to white, preparing for next
** collection cycle. Return where to continue the traversal or NULL if
-** list is finished. ('*countout' gets the number of elements traversed.)
+** list is finished.
*/
-static GCObject **sweeplist (lua_State *L, GCObject **p, int countin,
- int *countout) {
+static GCObject **sweeplist (lua_State *L, GCObject **p, int countin) {
global_State *g = G(L);
int ow = otherwhite(g);
int i;
@@ -839,8 +838,6 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, int countin,
p = &curr->next; /* go to next element */
}
}
- if (countout)
- *countout = i; /* number of elements traversed */
return (*p == NULL) ? NULL : p;
}
@@ -851,7 +848,7 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, int countin,
static GCObject **sweeptolive (lua_State *L, GCObject **p) {
GCObject **old = p;
do {
- p = sweeplist(L, p, 1, NULL);
+ p = sweeplist(L, p, 1);
} while (p == old);
return p;
}
@@ -870,11 +867,8 @@ static GCObject **sweeptolive (lua_State *L, GCObject **p) {
*/
static void checkSizes (lua_State *L, global_State *g) {
if (!g->gcemergency) {
- if (g->strt.nuse < g->strt.size / 4) { /* string table too big? */
- l_mem olddebt = g->GCdebt;
+ if (g->strt.nuse < g->strt.size / 4) /* string table too big? */
luaS_resize(L, g->strt.size / 2);
- g->GCestimate += g->GCdebt - olddebt; /* correct estimate */
- }
}
}
@@ -935,12 +929,11 @@ static void GCTM (lua_State *L) {
/*
** Call a few finalizers
*/
-static int runafewfinalizers (lua_State *L, int n) {
+static void runafewfinalizers (lua_State *L, int n) {
global_State *g = G(L);
int i;
for (i = 0; i < n && g->tobefnz; i++)
GCTM(L); /* call one finalizer */
- return i;
}
@@ -1052,19 +1045,16 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
/*
** Set the "time" to wait before starting a new GC cycle; cycle will
-** start when memory use hits the threshold of ('estimate' * pause /
-** PAUSEADJ). (Division by 'estimate' should be OK: it cannot be zero,
-** because Lua cannot even start with less than PAUSEADJ bytes).
+** start when number of objects in use hits the threshold of
+** approximately ('marked' * pause / 100). (A direct multiplication
+** by 'pause' may overflow, and a direct division by 100 may undeflow
+** to zero. So, the division is done in two steps. 8 * 12 is near 100
+** and the division by 8 is cheap.)
*/
static void setpause (global_State *g) {
- l_mem threshold, debt;
- int pause = getgcparam(g->gcpause);
- l_mem estimate = g->GCestimate / PAUSEADJ; /* adjust 'estimate' */
- lua_assert(estimate > 0);
- threshold = (pause < MAX_LMEM / estimate) /* overflow? */
- ? estimate * pause /* no overflow */
- : MAX_LMEM; /* overflow; truncate to maximum */
- debt = gettotalbytes(g) - threshold;
+ unsigned int pause = getgcparam(g->gcpause);
+ lu_mem threshold = g->marked / 8 * pause / 12;
+ l_mem debt = gettotalobjs(g) - threshold;
if (debt > 0) debt = 0;
luaE_setdebt(g, debt);
}
@@ -1306,17 +1296,17 @@ static void atomic2gen (lua_State *L, global_State *g) {
g->gckind = KGC_GEN;
g->lastatomic = 0;
- g->GCestimate = gettotalbytes(g); /* base for memory control */
+ g->GCestimate = gettotalobjs(g); /* base for memory control */
finishgencycle(L, g);
}
/*
** Set debt for the next minor collection, which will happen when
-** memory grows 'genminormul'%.
+** total number of objects grows 'genminormul'%.
*/
static void setminordebt (global_State *g) {
- luaE_setdebt(g, -(cast(l_mem, (gettotalbytes(g) / 100)) * g->genminormul));
+ luaE_setdebt(g, -(cast(l_mem, (gettotalobjs(g) / 100)) * g->genminormul));
}
@@ -1326,14 +1316,12 @@ static void setminordebt (global_State *g) {
** are cleared. Then, turn all objects into old and finishes the
** collection.
*/
-static lu_mem entergen (lua_State *L, global_State *g) {
- lu_mem numobjs;
+static void entergen (lua_State *L, global_State *g) {
luaC_runtilstate(L, bitmask(GCSpause)); /* prepare to start a new cycle */
luaC_runtilstate(L, bitmask(GCSpropagate)); /* start new cycle */
- numobjs = atomic(L); /* propagates all and then do the atomic stuff */
+ atomic(L); /* propagates all and then do the atomic stuff */
atomic2gen(L, g);
setminordebt(g); /* set debt assuming next cycle will be minor */
- return numobjs;
}
@@ -1372,9 +1360,9 @@ void luaC_changemode (lua_State *L, int newmode) {
/*
** Does a full collection in generational mode.
*/
-static lu_mem fullgen (lua_State *L, global_State *g) {
+static void fullgen (lua_State *L, global_State *g) {
enterinc(g);
- return entergen(L, g);
+ entergen(L, g);
}
@@ -1400,22 +1388,22 @@ static lu_mem fullgen (lua_State *L, global_State *g) {
** ('g->lastatomic != 0' also means that the last collection was bad.)
*/
static void stepgenfull (lua_State *L, global_State *g) {
- lu_mem newatomic; /* count of traversed objects */
lu_mem lastatomic = g->lastatomic; /* count from last collection */
if (g->gckind == KGC_GEN) /* still in generational mode? */
enterinc(g); /* enter incremental mode */
luaC_runtilstate(L, bitmask(GCSpropagate)); /* start new cycle */
- newatomic = atomic(L); /* mark everybody */
- if (newatomic < lastatomic + (lastatomic >> 3)) { /* good collection? */
+ g->marked = 0;
+ atomic(L); /* mark everybody */
+ if (g->marked < lastatomic + (lastatomic >> 3)) { /* good collection? */
atomic2gen(L, g); /* return to generational mode */
setminordebt(g);
}
else { /* another bad collection; stay in incremental mode */
- g->GCestimate = gettotalbytes(g); /* first estimate */;
+ g->GCestimate = gettotalobjs(g); /* first estimate */;
+ g->lastatomic = g->marked;
entersweep(L);
luaC_runtilstate(L, bitmask(GCSpause)); /* finish collection */
setpause(g);
- g->lastatomic = newatomic;
}
}
@@ -1443,21 +1431,23 @@ static void genstep (lua_State *L, global_State *g) {
if (g->lastatomic != 0) /* last collection was a bad one? */
stepgenfull(L, g); /* do a full step */
else {
- lu_mem majorbase = g->GCestimate; /* memory after last major collection */
- lu_mem majorinc = (majorbase / 100) * getgcparam(g->genmajormul);
- if (g->GCdebt > 0 && gettotalbytes(g) > majorbase + majorinc) {
- lu_mem numobjs = fullgen(L, g); /* do a major collection */
- if (gettotalbytes(g) < majorbase + (majorinc / 2)) {
- /* collected at least half of memory growth since last major
+ l_mem majorbase = g->GCestimate; /* objects after last major collection */
+ l_mem majorinc = (majorbase / 100) * getgcparam(g->genmajormul);
+ if (g->GCdebt > 0 && gettotalobjs(g) > majorbase + majorinc) {
+ g->marked = 0;
+ fullgen(L, g); /* do a major collection */
+ if (gettotalobjs(g) < majorbase + (majorinc / 2)) {
+ /* collected at least half of object growth since last major
collection; keep doing minor collections. */
lua_assert(g->lastatomic == 0);
}
else { /* bad collection */
- g->lastatomic = numobjs; /* signal that last collection was bad */
+ g->lastatomic = g->marked; /* signal that last collection was bad */
setpause(g); /* do a long wait for next (major) collection */
}
}
else { /* regular case; do a minor collection */
+ g->marked = 0;
youngcollection(L, g);
setminordebt(g);
g->GCestimate = majorbase; /* preserve base value */
@@ -1522,9 +1512,9 @@ void luaC_freeallobjects (lua_State *L) {
}
-static lu_mem atomic (lua_State *L) {
+static l_mem atomic (lua_State *L) {
+ l_mem work = 0;
global_State *g = G(L);
- lu_mem work = 0;
GCObject *origweak, *origall;
GCObject *grayagain = g->grayagain; /* save original list */
g->grayagain = NULL;
@@ -1541,50 +1531,47 @@ static lu_mem atomic (lua_State *L) {
work += propagateall(g); /* propagate changes */
g->gray = grayagain;
work += propagateall(g); /* traverse 'grayagain' list */
- convergeephemerons(g);
+ work += convergeephemerons(g);
/* at this point, all strongly accessible objects are marked. */
/* Clear values from weak tables, before checking finalizers */
- clearbyvalues(g, g->weak, NULL);
- clearbyvalues(g, g->allweak, NULL);
+ work += clearbyvalues(g, g->weak, NULL);
+ work += clearbyvalues(g, g->allweak, NULL);
origweak = g->weak; origall = g->allweak;
separatetobefnz(g, 0); /* separate objects to be finalized */
work += markbeingfnz(g); /* mark objects that will be finalized */
work += propagateall(g); /* remark, to propagate 'resurrection' */
- convergeephemerons(g);
+ work += convergeephemerons(g);
/* at this point, all resurrected objects are marked. */
/* remove dead objects from weak tables */
- clearbykeys(g, g->ephemeron); /* clear keys from all ephemeron tables */
- clearbykeys(g, g->allweak); /* clear keys from all 'allweak' tables */
+ work += clearbykeys(g, g->ephemeron); /* clear keys from all ephemeron */
+ work += clearbykeys(g, g->allweak); /* clear keys from all 'allweak' */
/* clear values from resurrected weak tables */
- clearbyvalues(g, g->weak, origweak);
- clearbyvalues(g, g->allweak, origall);
+ work += clearbyvalues(g, g->weak, origweak);
+ work += clearbyvalues(g, g->allweak, origall);
luaS_clearcache(g);
g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */
lua_assert(g->gray == NULL);
- return work; /* estimate of slots marked by 'atomic' */
+ return work;
}
-static int sweepstep (lua_State *L, global_State *g,
- int nextstate, GCObject **nextlist) {
+static void sweepstep (lua_State *L, global_State *g,
+ int nextstate, GCObject **nextlist) {
if (g->sweepgc) {
l_mem olddebt = g->GCdebt;
- int count;
- g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX, &count);
+ g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
g->GCestimate += g->GCdebt - olddebt; /* update estimate */
- return count;
}
else { /* enter next state */
g->gcstate = nextstate;
g->sweepgc = nextlist;
- return 0; /* no work done */
}
}
-static lu_mem singlestep (lua_State *L) {
+static l_mem singlestep (lua_State *L) {
global_State *g = G(L);
- lu_mem work;
+ l_mem work;
lua_assert(!g->gcstopem); /* collector is not reentrant */
g->gcstopem = 1; /* no emergency collections while collecting */
switch (g->gcstate) {
@@ -1599,26 +1586,30 @@ static lu_mem singlestep (lua_State *L) {
g->gcstate = GCSenteratomic; /* finish propagate phase */
work = 0;
}
- else
- work = propagatemark(g); /* traverse one gray object */
+ else {
+ propagatemark(g); /* traverse one gray object */
+ work = 1;
+ }
break;
}
case GCSenteratomic: {
- work = atomic(L); /* work is what was traversed by 'atomic' */
+ work = atomic(L);
entersweep(L);
- g->GCestimate = gettotalbytes(g); /* first estimate */;
break;
}
case GCSswpallgc: { /* sweep "regular" objects */
- work = sweepstep(L, g, GCSswpfinobj, &g->finobj);
+ sweepstep(L, g, GCSswpfinobj, &g->finobj);
+ work = GCSWEEPMAX;
break;
}
case GCSswpfinobj: { /* sweep objects with finalizers */
- work = sweepstep(L, g, GCSswptobefnz, &g->tobefnz);
+ sweepstep(L, g, GCSswptobefnz, &g->tobefnz);
+ work = GCSWEEPMAX;
break;
}
case GCSswptobefnz: { /* sweep objects to be finalized */
- work = sweepstep(L, g, GCSswpend, NULL);
+ sweepstep(L, g, GCSswpend, NULL);
+ work = GCSWEEPMAX;
break;
}
case GCSswpend: { /* finish sweeps */
@@ -1630,7 +1621,8 @@ static lu_mem singlestep (lua_State *L) {
case GCScallfin: { /* call remaining finalizers */
if (g->tobefnz && !g->gcemergency) {
g->gcstopem = 0; /* ok collections during finalizers */
- work = runafewfinalizers(L, GCFINMAX) * GCFINALIZECOST;
+ runafewfinalizers(L, GCFINMAX);
+ work = GCFINMAX * GCFINALIZECOST;
}
else { /* emergency mode or no more finalizers */
g->gcstate = GCSpause; /* finish collection */
@@ -1666,18 +1658,16 @@ void luaC_runtilstate (lua_State *L, int statesmask) {
*/
static void incstep (lua_State *L, global_State *g) {
int stepmul = (getgcparam(g->gcstepmul) | 1); /* avoid division by 0 */
- l_mem debt = (g->GCdebt / WORK2MEM) * stepmul;
- l_mem stepsize = (g->gcstepsize <= log2maxs(l_mem))
- ? ((cast(l_mem, 1) << g->gcstepsize) / WORK2MEM) * stepmul
- : MAX_LMEM; /* overflow; keep maximum value */
+ l_mem debt = (g->GCdebt / 100) * stepmul;
+ l_mem stepsize = cast(l_mem, 1) << g->gcstepsize;
do { /* repeat until pause or enough "credit" (negative debt) */
- lu_mem work = singlestep(L); /* perform one single step */
+ l_mem work = singlestep(L); /* perform one single step */
debt -= work;
} while (debt > -stepsize && g->gcstate != GCSpause);
if (g->gcstate == GCSpause)
setpause(g); /* pause until next cycle */
else {
- debt = (debt / stepmul) * WORK2MEM; /* convert 'work units' to bytes */
+ debt = (debt / stepmul) * 100; /* apply step multiplier */
luaE_setdebt(g, debt);
}
}
@@ -1710,9 +1700,8 @@ static void fullinc (lua_State *L, global_State *g) {
/* finish any pending sweep phase to start a new cycle */
luaC_runtilstate(L, bitmask(GCSpause));
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 */
+ /* estimate must be correct after a full GC cycle */
setpause(g);
}
diff --git a/lgc.h b/lgc.h
@@ -135,10 +135,10 @@
#define getgcparam(p) ((p) * 4)
#define setgcparam(p,v) ((p) = (v) / 4)
-#define LUAI_GCMUL 100
+#define LUAI_GCMUL 300
-/* how much to allocate before next GC step (log2) */
-#define LUAI_GCSTEPSIZE 13 /* 8 KB */
+/* how many objects to allocate before next GC step (log2) */
+#define LUAI_GCSTEPSIZE 8 /* 256 objects */
/*
diff --git a/llimits.h b/llimits.h
@@ -57,7 +57,7 @@ typedef signed char ls_byte;
** floor of the log2 of the maximum signed value for integral type 't'.
** (That is, maximum 'n' such that '2^n' fits in the given signed type.)
*/
-#define log2maxs(t) (sizeof(t) * 8 - 2)
+#define log2maxs(t) cast_int(sizeof(t) * 8 - 2)
/*
diff --git a/lmem.c b/lmem.c
@@ -133,7 +133,7 @@ void luaM_free_ (lua_State *L, void *block, size_t osize) {
global_State *g = G(L);
lua_assert((osize == 0) == (block == NULL));
(*g->frealloc)(g->ud, block, osize, 0);
- g->GCdebt -= osize;
+ g->totalbytes -= osize;
}
@@ -167,10 +167,10 @@ void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
if (l_unlikely(newblock == NULL && nsize > 0)) {
newblock = tryagain(L, block, osize, nsize);
if (newblock == NULL) /* still no memory? */
- return NULL; /* do not update 'GCdebt' */
+ return NULL; /* do not update 'totalbytes' */
}
lua_assert((nsize == 0) == (newblock == NULL));
- g->GCdebt = (g->GCdebt + nsize) - osize;
+ g->totalbytes += nsize - osize;
return newblock;
}
@@ -195,7 +195,7 @@ void *luaM_malloc_ (lua_State *L, size_t size, int tag) {
if (newblock == NULL)
luaM_error(L);
}
- g->GCdebt += size;
+ g->totalbytes += size;
return newblock;
}
}
diff --git a/lstate.c b/lstate.c
@@ -83,15 +83,15 @@ static unsigned int luai_makeseed (lua_State *L) {
/*
-** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
-** invariant (and avoiding underflows in 'totalbytes')
+** set GCdebt to a new value keeping the value (totalobjs + GCdebt)
+** invariant (and avoiding underflows in 'totalobjs')
*/
void luaE_setdebt (global_State *g, l_mem debt) {
- l_mem tb = gettotalbytes(g);
+ l_mem tb = gettotalobjs(g);
lua_assert(tb > 0);
if (debt < tb - MAX_LMEM)
- debt = tb - MAX_LMEM; /* will make 'totalbytes == MAX_LMEM' */
- g->totalbytes = tb - debt;
+ debt = tb - MAX_LMEM; /* will make 'totalobjs == MAX_LMEM' */
+ g->totalobjs = tb - debt;
g->GCdebt = debt;
}
@@ -278,8 +278,8 @@ static void close_state (lua_State *L) {
}
luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
freestack(L);
- lua_assert(gettotalbytes(g) == sizeof(LG));
- lua_assert(g->totalobjs == 1);
+ lua_assert(g->totalbytes == sizeof(LG));
+ lua_assert(gettotalobjs(g) == 1);
(*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */
}
@@ -389,6 +389,7 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
g->twups = NULL;
g->totalbytes = sizeof(LG);
g->totalobjs = 1;
+ g->marked = 0;
g->GCdebt = 0;
g->lastatomic = 0;
setivalue(&g->nilvalue, 0); /* to signal that state is not yet built */
diff --git a/lstate.h b/lstate.h
@@ -249,9 +249,10 @@ typedef struct CallInfo {
typedef struct global_State {
lua_Alloc frealloc; /* function to reallocate memory */
void *ud; /* auxiliary data to 'frealloc' */
- l_mem totalbytes; /* number of bytes currently allocated - GCdebt */
- l_mem totalobjs; /* total number of objects allocated */
+ l_mem totalbytes; /* number of bytes currently allocated */
+ l_mem totalobjs; /* total number of objects allocated - GCdebt */
l_mem GCdebt; /* bytes allocated not yet compensated by the collector */
+ lu_mem marked; /* number of objects marked in a GC cycle */
lu_mem GCestimate; /* an estimate of the non-garbage memory in use */
lu_mem lastatomic; /* see function 'genstep' in file 'lgc.c' */
stringtable strt; /* hash table for strings */
@@ -386,8 +387,9 @@ union GCUnion {
#define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc))
-/* actual number of total bytes allocated */
-#define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
+/* actual number of total objects allocated */
+#define gettotalobjs(g) ((g)->totalobjs + (g)->GCdebt)
+
LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
diff --git a/ltests.c b/ltests.c
@@ -1027,6 +1027,16 @@ static int table_query (lua_State *L) {
}
+static int query_inc (lua_State *L) {
+ global_State *g = G(L);
+ lua_pushinteger(L, gettotalobjs(g));
+ lua_pushinteger(L, g->GCdebt);
+ lua_pushinteger(L, getgcparam(g->gcpause));
+ lua_pushinteger(L, getgcparam(g->gcstepmul));
+ lua_pushinteger(L, cast(l_mem, 1) << g->gcstepsize);
+ return 5;
+}
+
static int string_query (lua_State *L) {
stringtable *tb = &G(L)->strt;
int s = cast_int(luaL_optinteger(L, 1, 0)) - 1;
@@ -1933,6 +1943,7 @@ static const struct luaL_Reg tests_funcs[] = {
{"pushuserdata", pushuserdata},
{"querystr", string_query},
{"querytab", table_query},
+ {"queryinc", query_inc},
{"ref", tref},
{"resume", coresume},
{"s2d", s2d},
diff --git a/lua.c b/lua.c
@@ -633,7 +633,8 @@ static int pmain (lua_State *L) {
}
luaL_openlibs(L); /* open standard libraries */
createargtable(L, argv, argc, script); /* create table 'arg' */
- lua_gc(L, LUA_GCGEN, 0, 0); /* GC in generational mode */
+ lua_gc(L, LUA_GCRESTART); /* start GC... */
+ lua_gc(L, LUA_GCGEN, 0, 0); /* ...in generational mode */
if (!(args & has_E)) { /* no option '-E'? */
if (handle_luainit(L) != LUA_OK) /* run LUA_INIT */
return 0; /* error running LUA_INIT */
@@ -665,6 +666,7 @@ int main (int argc, char **argv) {
l_message(argv[0], "cannot create state: not enough memory");
return EXIT_FAILURE;
}
+ lua_gc(L, LUA_GCSTOP); /* stop GC while buidling state */
lua_pushcfunction(L, &pmain); /* to call 'pmain' in protected mode */
lua_pushinteger(L, argc); /* 1st argument */
lua_pushlightuserdata(L, argv); /* 2nd argument */
