lua

A copy of the Lua development repository
Log | Files | Refs | README

commit 8d4feb504f34c182ad991102d5ccd974b3a5f1b8
parent d77a7a8c26b54d9fad496e50c2f5c86516924939
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date:   Thu, 31 Mar 2016 16:01:37 -0300

do not try to ensure that 'sweepgc' points to a live object
when entering sweep phase ('entersweep'); that may be too
expensive to be done still inside the atomic step. Walking
one single object more often than not will work.

Diffstat:
Mlgc.c | 29+++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/lgc.c b/lgc.c @@ -1,5 +1,5 @@ /* -** $Id: lgc.c,v 2.210 2015/11/03 18:10:44 roberto Exp roberto $ +** $Id: lgc.c,v 2.211 2015/12/10 18:12:30 roberto Exp roberto $ ** Garbage Collector ** See Copyright Notice in lua.h */ @@ -754,14 +754,11 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) { /* ** sweep a list until a live object (or end of list) */ -static GCObject **sweeptolive (lua_State *L, GCObject **p, int *n) { +static GCObject **sweeptolive (lua_State *L, GCObject **p) { GCObject **old = p; - int i = 0; do { - i++; p = sweeplist(L, p, 1); } while (p == old); - if (n) *n += i; return p; } @@ -909,7 +906,7 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) { if (issweepphase(g)) { makewhite(g, o); /* "sweep" object 'o' */ if (g->sweepgc == &o->next) /* should not remove 'sweepgc' object */ - g->sweepgc = sweeptolive(L, g->sweepgc, NULL); /* change 'sweepgc' */ + g->sweepgc = sweeptolive(L, g->sweepgc); /* change 'sweepgc' */ } /* search for pointer pointing to 'o' */ for (p = &g->allgc; *p != o; p = &(*p)->next) { /* empty */ } @@ -951,19 +948,16 @@ static void setpause (global_State *g) { /* ** Enter first sweep phase. -** The call to 'sweeptolive' makes pointer point to an object inside -** the list (instead of to the header), so that the real sweep do not -** need to skip objects created between "now" and the start of the real -** sweep. -** Returns how many objects it swept. +** The call to 'sweeplist' tries to make pointer point to an object +** inside the list (instead of to the header), so that the real sweep do +** not need to skip objects created between "now" and the start of the +** real sweep. */ -static int entersweep (lua_State *L) { +static void entersweep (lua_State *L) { global_State *g = G(L); - int n = 0; g->gcstate = GCSswpallgc; lua_assert(g->sweepgc == NULL); - g->sweepgc = sweeptolive(L, &g->allgc, &n); - return n; + g->sweepgc = sweeplist(L, &g->allgc, 1); } @@ -1064,12 +1058,11 @@ static lu_mem singlestep (lua_State *L) { } case GCSatomic: { lu_mem work; - int sw; propagateall(g); /* make sure gray list is empty */ work = atomic(L); /* work is what was traversed by 'atomic' */ - sw = entersweep(L); + entersweep(L); g->GCestimate = gettotalbytes(g); /* first estimate */; - return work + sw * GCSWEEPCOST; + return work; } case GCSswpallgc: { /* sweep "regular" objects */ return sweepstep(L, g, GCSswpfinobj, &g->finobj);