David Hildenbrand <david@xxxxxxxxxx> wrote: > >> percpu counters maybe - add them up at the point of viewing? > > They are percpu, see my last email. But for every 108 changes (on > > my system), they will do two atomic_long_adds(). So not very > > useful for anything but low frequency modifications. > > > > Can we just treat the whole acquired/released accounting as a debug mechanism > to detect missing releases and do it only for debug kernels? > > > The pcpu counter is an s8, so we have to flush on a regular basis and cannot > really defer it any longer ... but I'm curious if it would be of any help to > only have a single PINNED counter that goes into both directions (inc/dec on > pin/release), to reduce the flushing. > > Of course, once we pin/release more than ~108 pages in one go or we switch > CPUs frequently it won't be that much of a help ... What are the stats actually used for? Is it just debugging, or do we actually have users for them (control groups spring to mind)? David
