Changed signal of GC debt

Positive debts seems more natural then negative ones.
This commit is contained in:
Roberto Ierusalimschy 2022-12-13 15:45:57 -03:00
parent 40565b4a08
commit 5d8b5b9290
6 changed files with 22 additions and 25 deletions

8
lapi.c
View File

@ -1168,8 +1168,8 @@ LUA_API int lua_gc (lua_State *L, int what, ...) {
g->gcstp = 0; /* allow GC to run (bit GCSTPGC must be zero here) */
if (todo == 0)
todo = 1 << g->gcstepsize; /* standard step size */
while (todo + g->GCdebt > 0) { /* enough to run a step? */
todo += g->GCdebt; /* decrement 'todo' (debt is usually negative) */
while (todo >= g->GCdebt) { /* enough to run a step? */
todo -= g->GCdebt; /* decrement 'todo' */
luaC_step(L); /* run one basic step */
didsomething = 1;
if (g->gckind == KGC_GEN) /* minor collections? */
@ -1177,8 +1177,8 @@ LUA_API int lua_gc (lua_State *L, int what, ...) {
else if (g->gcstate == GCSpause)
break; /* don't run more than one cycle */
}
/* add remaining 'todo' to total debt */
luaE_setdebt(g, todo + g->GCdebt);
/* remove remaining 'todo' from total debt */
luaE_setdebt(g, g->GCdebt - todo);
g->gcstp = oldstp; /* restore previous state */
if (didsomething && g->gcstate == GCSpause) /* end of cycle? */
res = 1; /* signal it */

16
lgc.c
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@ -242,7 +242,7 @@ 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->GCdebt++;
g->GCdebt--;
o->marked = luaC_white(g);
o->tt = tt;
o->next = g->allgc;
@ -1034,8 +1034,8 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
*/
static void setpause (global_State *g) {
l_obj threshold = applygcparam(g, gcpause, g->marked);
l_obj debt = gettotalobjs(g) - threshold;
if (debt > 0) debt = 0;
l_obj debt = threshold - gettotalobjs(g);
if (debt < 0) debt = 0;
luaE_setdebt(g, debt);
}
@ -1285,7 +1285,7 @@ static void atomic2gen (lua_State *L, global_State *g) {
** total number of objects grows 'genminormul'%.
*/
static void setminordebt (global_State *g) {
luaE_setdebt(g, -applygcparam(g, genminormul, gettotalobjs(g)));
luaE_setdebt(g, applygcparam(g, genminormul, gettotalobjs(g)));
}
@ -1378,13 +1378,13 @@ static void genmajorstep (lua_State *L, global_State *g) {
** Does a generational "step". If the total number of objects grew
** more than 'majormul'% since the last major collection, does a
** major collection. Otherwise, does a minor collection. The test
** ('GCdebt' > 0) avoids major collections when the step originated from
** ('GCdebt' != 0) avoids major collections when the step originated from
** 'collectgarbage("step")'.
*/
static void genstep (lua_State *L, global_State *g) {
l_obj majorbase = g->GClastmajor; /* count after last major collection */
l_obj majorinc = applygcparam(g, genmajormul, majorbase);
if (g->GCdebt > 0 && gettotalobjs(g) > majorbase + majorinc) {
if (g->GCdebt != 0 && gettotalobjs(g) > majorbase + majorinc) {
/* do a major collection */
enterinc(g);
g->gckind = KGC_GENMAJOR;
@ -1605,7 +1605,7 @@ static void incstep (lua_State *L, global_State *g) {
if (g->gcstate == GCSpause)
setpause(g); /* pause until next cycle */
else {
luaE_setdebt(g, -stepsize);
luaE_setdebt(g, stepsize);
}
}
@ -1618,7 +1618,7 @@ void luaC_step (lua_State *L) {
global_State *g = G(L);
lua_assert(!g->gcemergency);
if (!gcrunning(g)) /* not running? */
luaE_setdebt(g, -2000);
luaE_setdebt(g, 2000);
else {
switch (g->gckind) {
case KGC_INC:

4
lgc.h
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@ -175,13 +175,13 @@
/*
** Does one step of collection when debt becomes positive. 'pre'/'pos'
** Does one step of collection when debt becomes zero. 'pre'/'pos'
** allows some adjustments to be done only when needed. macro
** 'condchangemem' is used only for heavy tests (forcing a full
** GC cycle on every opportunity)
*/
#define luaC_condGC(L,pre,pos) \
{ if (G(L)->GCdebt > 0) { pre; luaC_step(L); pos;}; \
{ if (G(L)->GCdebt <= 0) { pre; luaC_step(L); pos;}; \
condchangemem(L,pre,pos); }
/* more often than not, 'pre'/'pos' are empty */

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@ -33,6 +33,8 @@ typedef unsigned long lu_mem;
typedef long l_obj;
#endif /* } */
#define MAX_LOBJ cast(l_obj, ~cast(lu_mem, 0) >> 1)
/* chars used as small naturals (so that 'char' is reserved for characters) */
typedef unsigned char lu_byte;
@ -47,11 +49,6 @@ typedef signed char ls_byte;
: (size_t)(LUA_MAXINTEGER))
#define MAX_LUMEM ((lu_mem)(~(lu_mem)0))
#define MAX_LMEM ((l_obj)(MAX_LUMEM >> 1))
#define MAX_INT INT_MAX /* maximum value of an int */

View File

@ -89,9 +89,9 @@ static unsigned int luai_makeseed (lua_State *L) {
void luaE_setdebt (global_State *g, l_obj debt) {
l_obj tb = gettotalobjs(g);
lua_assert(tb > 0);
if (debt < tb - MAX_LMEM)
debt = tb - MAX_LMEM; /* will make 'totalobjs == MAX_LMEM' */
g->totalobjs = tb - debt;
if (debt > MAX_LOBJ - tb)
debt = MAX_LOBJ - tb; /* will make 'totalobjs == MAX_LMEM' */
g->totalobjs = tb + debt;
g->GCdebt = debt;
}

View File

@ -251,8 +251,8 @@ typedef struct global_State {
lua_Alloc frealloc; /* function to reallocate memory */
void *ud; /* auxiliary data to 'frealloc' */
lu_mem totalbytes; /* number of bytes currently allocated */
l_obj totalobjs; /* total number of objects allocated - GCdebt */
l_obj GCdebt; /* bytes allocated not yet compensated by the collector */
l_obj totalobjs; /* total number of objects allocated + GCdebt */
l_obj GCdebt; /* objects counted but not yet allocated */
l_obj marked; /* number of objects marked in a GC cycle */
l_obj GClastmajor; /* objects at last major collection */
stringtable strt; /* hash table for strings */
@ -388,7 +388,7 @@ union GCUnion {
/* actual number of total objects allocated */
#define gettotalobjs(g) ((g)->totalobjs + (g)->GCdebt)
#define gettotalobjs(g) ((g)->totalobjs - (g)->GCdebt)
LUAI_FUNC void luaE_setdebt (global_State *g, l_obj debt);