On Mon 05-09-16 16:14:06, robert.foss@xxxxxxxxxxxxx wrote: > From: Robert Foss <robert.foss@xxxxxxxxxxxxx> > > This series provides the /proc/PID/totmaps feature, which > summarizes the information provided by /proc/PID/smaps for > improved performance and usability reasons. > > A use case is to speed up monitoring of memory consumption in > environments where RSS isn't precise. > > For example Chrome tends to many processes which have hundreds of VMAs > with a substantial amount of shared memory, and the error of using > RSS rather than PSS tends to be very large when looking at overall > memory consumption. PSS isn't kept as a single number that's exported > like RSS, so to calculate PSS means having to parse a very large smaps > file. > > This process is slow and has to be repeated for many processes, and we > found that the just act of doing the parsing was taking up a > significant amount of CPU time, so this patch is an attempt to make > that process cheaper. I still maintain my concerns about a single pss value. It might work in a very specific situations where the consumer knows what is shared but other than that the value can be more misleading than helpful. So a NACK from me until I am shown that this is usable in general and still helpful. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
