On 9/13/22 18:51, Joe Damato wrote: > TLB shootdowns are tracked globally, but on a busy system it can be > difficult to disambiguate the source of TLB shootdowns. > > Add two counter fields: > - nrtlbflush: number of tlb flush events received > - ngtlbflush: number of tlb flush events generated > > Expose those fields in /proc/[pid]/stat so that they can be analyzed > alongside similar metrics (e.g. min_flt and maj_flt). On x86 at least, we already have two other ways to count flushes. You even quoted them with your patch: > count_vm_tlb_event(NR_TLB_REMOTE_FLUSH); > + current->ngtlbflush++; > if (info->end == TLB_FLUSH_ALL) > trace_tlb_flush(TLB_REMOTE_SEND_IPI, TLB_FLUSH_ALL); Granted, the count_vm_tlb...() one is debugging only. But, did you try to use those other mechanisms? For instance, could you patch count_vm_tlb_event()? Why didn't the tracepoints work for you? Can this be done in a more arch-generic way? It's a shame to unconditionally add counters to the task struct and only use them on x86. If someone wanted to generalize the x86 tracepoints, or make them available to other architectures, I think that would be fine even if they have to change a bit (queue the inevitable argument about tracepoint ABI). P.S. I'm not a fan of the structure member naming.
