> From: Ma, Liang J
> Sent: Tuesday, March 13, 2018 11:34 AM
> To: jerin.ja...@caviumnetworks.com
> Cc: dev@dpdk.org; Van Haaren, Harry <harry.van.haa...@intel.com>; Jain, Deepak
> K <deepak.k.j...@intel.com>; Geary, John <john.ge...@intel.com>; Mccarthy,
> Peter <peter.mccar...@intel.com>
> Subject: [PATCH] event/opdl: fix atomic queue race condition issue
>
> If application link one atomic queue to multiple ports,
> and each worker core update flow_id, there will have a
> chance to hit race condition issue and lead to double processing
> same event. This fix solve the problem and eliminate
> the race condition issue.
>
> Fixes: 4236ce9bf5bf ("event/opdl: add OPDL ring infrastructure library")
>
General notes
- Spaces around & % << >> and other bitwise manipulations
(https://dpdk.org/doc/guides/contributing/coding_style.html#operators)
- I've noted a few below, but there are more
- Usually checkpatch flags these - I'm curious why it didn't in this case
It would be nice if we didn't have to rely on __atomic_load_n() and friends,
however I don't see a better alternative. Given other DPDK components are
also using __atomic_* functions, no objection here.
<snip>
> @@ -520,7 +528,17 @@ opdl_stage_claim_singlethread(struct opdl_stage *s, void
> *entries,
>
> for (j = 0; j < num_entries; j++) {
> ev = (struct rte_event *)get_slot(t, s->head+j);
> - if ((ev->flow_id%s->nb_instance) == s->instance_id) {
Spaces around the %
> +
> + event = __atomic_load_n(&(ev->event),
> + __ATOMIC_ACQUIRE);
> +
> + opa_id = OPDL_OPA_MASK&(event>>OPDL_OPA_OFFSET);
Spaces &
> + flow_id = OPDL_FLOWID_MASK&event;
Spaces &
> +
> + if (opa_id >= s->queue_id)
> + continue;
> +
> + if ((flow_id%s->nb_instance) == s->instance_id) {
Spaces %
<snip rest of patch>
Will re-review v2. Cheers, -Harry
