On Wed, 2016-08-17 at 12:33 -0700, John Fastabend wrote:
> This patch adds a flag for queueing disciplines to indicate the stack
> does not need to use the qdisc lock to protect operations. This can
> be used to build lockless scheduling algorithms and improving
> performance.
>
> The flag is checked in the tx path and the qdisc lock is only taken
> if it is not set. For now use a conditional if statement. Later we
> could be more aggressive if it proves worthwhile and use a static key
> or wrap this in a likely().
>
> Signed-off-by: John Fastabend <john.r.fastab...@intel.com>
> ---
> include/net/pkt_sched.h | 4 +++-
> include/net/sch_generic.h | 1 +
> net/core/dev.c | 32 ++++++++++++++++++++++++++++----
> net/sched/sch_generic.c | 26 ++++++++++++++++----------
> 4 files changed, 48 insertions(+), 15 deletions(-)
>
> diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
> index 7caa99b..69540c6 100644
> --- a/include/net/pkt_sched.h
> +++ b/include/net/pkt_sched.h
> @@ -107,8 +107,10 @@ void __qdisc_run(struct Qdisc *q);
>
> static inline void qdisc_run(struct Qdisc *q)
> {
> - if (qdisc_run_begin(q))
> + if (qdisc_run_begin(q)) {
> __qdisc_run(q);
> + qdisc_run_end(q);
> + }
> }
Looks like you could have a separate patch, removing qdisc_run_end()
call done in __qdisc_run(q) ?
Then the 'allow qdiscs to handle locking'
