Re: Behavior of luaC_barrierback at sweep phase

[Roberto Ierusalimschy <roberto@...>]

> >i think luaC_barrierback should change table from black to current white directly at sweep phase.  please correct me if my statement is wrong.
> 
> this is what the forward barrier will do. the backward barrier could do this at the sweep phase of course, in which
> case it just behaves like a forward barrier. IMHO you shift the later sweep operation ahead, but you don't gain much.
> when the gc encounter the table when sweep the list, it will check aliveness of the table and sweep it again anyway.

I guess it gains nothing. In fact, it loses something, because
'luaC_barrierback_' becomes slower due to the extra test.

-- Roberto