[Antoine Pitrou] >> Would it be helpful if the GC was informed of memory growth by the >> Python memory allocator (that is, each time it either asks or gives back >> a block of memory to the system allocator) ?
[Martin v. Löwis] > I don't see how. The garbage collector is already informed about memory > growth; it learns exactly when a container object is allocated or > deallocated. That the allocator then requests memory from the system > only confirms what the garbage collector already knew: that there are > lots of allocated objects. From that, one could infer that it might > be time to perform garbage collection - or one could infer that all > the objects are really useful, and no garbage can be collected. Really the same conundrum we currently face: cyclic gc is currently triggered by reaching a certain /excess/ of allocations over deallocations. From that we /do/ infer it's time to perform garbage collection -- but, as some examples here showed, it's sometimes really the case that the true meaning of the excess is that "all the objects are really useful, and no garbage can be collected -- and I'm creating a lot of them". pymalloc needing to allocate a new arena would be a different way to track an excess of allocations over deallocations, and in some ways more sensible (since it would reflect an excess of /bytes/ allocated over bytes freed, rather than an excess in the counts of objects allocated-over-freed regardless of their sizes -- an implication is, e.g., that cyclic gc would be triggered much less frequently by mass creation of small tuples than of small dicts, since a small tuple consumes much less memory than a small dict). Etc. ;-) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
