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Re: GUILE GC -- Write barrier for vectors
From: |
Han-Wen |
Subject: |
Re: GUILE GC -- Write barrier for vectors |
Date: |
Wed, 17 Jul 2002 23:53:54 +0200 |
address@hidden writes:
> > I'm reading the patent (gosh, what verbosity) -- but interestingly,
> > the claim is only made for not copying entire pages (cards in Scheme
> > terms), that are marked conservatively. If you one uses a second set
> > of mark bits, you could leave alone exactly those objects that are
> > marked conservatively (iso. the whole page). The price is that you
> > have another mark-bit vector (1.5 % memory overhead), that the free
> > space in the conservatively marked pages is fragmented, and that there
> > is more overhead (checking the marked-conservatively-bit) during the
> > copy phase.
>
> Interesting. But: isn't the conservatively marked page fragmented
> anyway? At some time a few objects in a conservatively marked page will
> be collected. That is, wouldn't we need to keep track of conservatively
> marked cells (in contrast to pages) anyway?
Yes, but the point is that you can not move marked cells in a
conservatively marked page. Somewhere along the line (if you do
copying GC), you have to say
if (conservatively_marked (cell))
;
else
copy_cell_to_new_location ()
for bartlett conservatively_marked() equals "this page contains a
conservatively_marked object".
--
Han-Wen Nienhuys | address@hidden | http://www.cs.uu.nl/~hanwen
- Re: GUILE GC -- Write barrier for vectors, (continued)
- Re: GUILE GC -- Write barrier for vectors, Miroslav Silovic, 2002/07/15
- Re: GUILE GC -- Write barrier for vectors, Dirk Herrmann, 2002/07/15
- Re: GUILE GC -- Write barrier for vectors, Han-Wen Nienhuys, 2002/07/15
- Re: GUILE GC -- Write barrier for vectors, Dirk Herrmann, 2002/07/15
- Re: GUILE GC -- Write barrier for vectors, Han-Wen, 2002/07/15
- Re: GUILE GC -- Write barrier for vectors, Han-Wen Nienhuys, 2002/07/16
- Re: GUILE GC -- Write barrier for vectors, Dirk Herrmann, 2002/07/16
- Re: GUILE GC -- Write barrier for vectors, Han-Wen, 2002/07/16
- Re: GUILE GC -- Write barrier for vectors,
Han-Wen <=
- Re: GUILE GC -- Write barrier for vectors, Dirk Herrmann, 2002/07/19