Memory leak (small in vanilla, large with mods)
OpenMW version 0.36.1, revision ba79d319, on Arch Linux.
I first noticed the issue when playing with mods, and my RAM usage hit 98%. I successfully reproduced it, to a significantly lesser degree, with a fresh vanilla character.
Changing cells causes a small memory leak in vanilla (MW, TB, BM). To reproduce, I made a new character, console-buffed Strength, Speed, Athletics, and Acrobatics, and did a run/jump trip in the following order: Seyda Neen -> Gnisis -> Dagon Fel -> Sadrith Mora -> Vivec -> Seyda Neen. This trip almost doubled OpenMW's RAM usage. I also tried coc'ing back and forth between cities, but this doesn't seem to reproduce the issue (is the engine smart about caching? it looks like it is).
During vanilla play, this many cell changes is probably several hours of play, and not a huge deal. But when I play with mods, one or more of the mods causes the issue to be 20-30x worse. Short trips like Balmora to Caldera, on foot, cause initial memory usage to double. The severity of the leak restricts my play sessions to a max of 20-30 minutes. (Unfortunately, I have a lot of mods, and don't know which one (or more) causes the increase.)
(RM-2881 from redmine: created on 2015-08-20 by Tyler Robertson, , closed on 2017-02-24 by nobody)