Hi! I'm not sure is it good idea to include .u files in usual rotation process at all, and especially handle them just like .s files. If several crashes happens for some reason in a short period of time this will result in deletion of all log files except last (say) 10 .u files, which are usually small and may contain just one line. Replacing 10MB of last logs with 10 last log lines doesn't sounds like a nice idea.
Possible "right" solution will be to keep same amount of last .u files as configured for .s files, i.e. if we've configured to keep last 10 files then we may have at most double amount (10 .u files and 10 .s files). (I didn't checked mentioned patches, so maybe they already works this way.) -- WBR, Alex.