On Fri, Jun 5, 2020, at 3:13 PM, Rémi Dettai wrote: > Hi Antoine ! > > I would indeed have expected jemalloc to do that (remap the pages) > I have no idea about the performance gain this would provide (if any). > Could be interesting to explore.
This would actually be the most interesting thing. In general, getting access to the pages mapped into RAM would improve in a lot of more situations, not just realloction. For example, when you take a small slice of a large array and only pass this on, but don't an explicit reference to the array, you will still indirectly hold on the larger memory size. Having an allocator that would understand the mapping between pages and memory block would allow us to free the pages that are not part of the view. Also, yes: For CSV and JSON, we don't have size estimates beforehand. There this would be a great performance improvement. Best Uwe
