On Thu, 20 Oct 2011 17:13:46 +0200 (CEST) Marc Glisse <marc.gli...@inria.fr> wrote:
> Can't you use GTY-ed memory in PPL? Sorry for the naive question, but > std::vector can take an allocator parameter, gmp lets you specify an > allocation function... I believe that the PPL C++ code don't have any kind of allocator parameters. But I am not sure it would help. Let's take just a std::string allocated with an allocator that would use Ggc-ed memory, and appearing inside a GTY-ed data. How that Ggc-ed memory used for the string will be marked, and how will it be released? The usual way to release memory allocated by Ggc is inside ggc_collect (e.g. by sweep_pages) and that happens when the object has not been marked (because Ggc is a precise mark&sweep collector). And because C++ collections don't offer (AFAIK) any support to scan all their internal data (so if std::string implementation actually contains a pointer to some internal buffer which would have been Ggc-allocated because the string has been created using our putative Ggc C++ allocator) it seems to me that the only way to make it work is to have the C++ destructor of our std::string called from inside Ggc. This is what I call finalized objects (or destroyable objects) inside Ggc. Or did I not understood something about your question? Cheers -- Basile STARYNKEVITCH http://starynkevitch.net/Basile/ email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359 8, rue de la Faiencerie, 92340 Bourg La Reine, France *** opinions {are only mine, sont seulement les miennes} ***
