On Thu, May 19, 2016 at 5:35 AM, Eric Dumazet <eric.duma...@gmail.com> wrote: > > These stats are using u64 or u32 fields, so reading integral values > should not prevent writers from doing concurrent updates if the kernel > arch is a 64bit one. > > Being able to atomically fetch all counters like packets and bytes sent > at the expense of interfering in fast path (queue and dequeue packets) > is simply not worth the pain, as the values are generally stale after 1 > usec.
I think one purpose of this lock is to make sure we have an atomic snapshot of these counters as a whole. IOW, we may need another lock rather than the qdisc root lock to guarantee this.
