Comment (by Roland Haas):

In the plot that I linked to: rss. Please note that the job was constructed such that each process used less than 2GB of RAM so mallinfo's rssnumber is trustworthy. The other quantity plotted uordblks plotted is the amount of memory that malloc handed to its client code and that (thankfully) went down with the patch that free()ed the temporarily allocated procbuf buffers.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2194/memory-increase-during-regridding