On 22/01/19 21:48, Greg Kroah-Hartman wrote: >> This also brings the question: shall we move these counters out of debugfs into something else? > If you have code that relies on debugfs, yes, you need to move that out > of debugfs because more and more systems are trying to disable it due to > the obvious problems with it (i.e. leaking tons of debugging > information). > > debugfs is for DEBUG information, not for "statistics about how my VM is > working". That sounds like something you need to rely on, so debugfs is > not the place for it. Yes, we know that and tracepoints are already one replacement. However, they are slower that just a lock-free "vcpu->stats.foo_happened++". Another idea that Steven Rostedt and I discussed a while ago is some kind of "statfs" which would already provide some code, similar to the one that KVM uses to accumulate statistics from multiple VMs or multiple VCPUs into a single counter. Paolo
