From: Po Liu <po.liu@nxp.com>
To: Vlad Buslov <vlad@buslov.dev>
Cc: "davem@davemloft.net" <davem@davemloft.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"vinicius.gomes@intel.com" <vinicius.gomes@intel.com>,
Claudiu Manoil <claudiu.manoil@nxp.com>,
Vladimir Oltean <vladimir.oltean@nxp.com>,
Alexandru Marginean <alexandru.marginean@nxp.com>,
"michael.chan@broadcom.com" <michael.chan@broadcom.com>,
"vishal@chelsio.com" <vishal@chelsio.com>,
"saeedm@mellanox.com" <saeedm@mellanox.com>,
"leon@kernel.org" <leon@kernel.org>,
"jiri@mellanox.com" <jiri@mellanox.com>,
"idosch@mellanox.com" <idosch@mellanox.com>,
"alexandre.belloni@bootlin.com" <alexandre.belloni@bootlin.com>,
"UNGLinuxDriver@microchip.com" <UNGLinuxDriver@microchip.com>,
"kuba@kernel.org" <kuba@kernel.org>,
"jhs@mojatatu.com" <jhs@mojatatu.com>,
"xiyou.wangcong@gmail.com" <xiyou.wangcong@gmail.com>,
"simon.horman@netronome.com" <simon.horman@netronome.com>,
"pablo@netfilter.org" <pablo@netfilter.org>,
"moshe@mellanox.com" <moshe@mellanox.com>,
"m-karicheri2@ti.com" <m-karicheri2@ti.com>,
"andre.guedes@linux.intel.com" <andre.guedes@linux.intel.com>,
"stephen@networkplumber.org" <stephen@networkplumber.org>
Subject: RE: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow action
Date: Thu, 23 Apr 2020 09:15:50 +0000 [thread overview]
Message-ID: <VE1PR04MB6496F4805BCF53AF5889CB3892D30@VE1PR04MB6496.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <VE1PR04MB6496AAA71717BBAD4C4CE2BC92D30@VE1PR04MB6496.eurprd04.prod.outlook.com>
Hi Vlad Buslov,
> > >> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
> {
> > >> > + struct gate_action *gact = container_of(timer, struct
> gate_action,
> > >> > + hitimer);
> > >> > + struct tcf_gate_params *p = get_gate_param(gact);
> > >> > + struct tcfg_gate_entry *next;
> > >> > + ktime_t close_time, now;
> > >> > +
> > >> > + spin_lock(&gact->entry_lock);
> > >> > +
> > >> > + next = rcu_dereference_protected(gact->next_entry,
> > >> > +
> > >> > + lockdep_is_held(&gact->entry_lock));
> > >> > +
> > >> > + /* cycle start, clear pending bit, clear total octets */
> > >> > + gact->current_gate_status = next->gate_state ?
> > >> GATE_ACT_GATE_OPEN : 0;
> > >> > + gact->current_entry_octets = 0;
> > >> > + gact->current_max_octets = next->maxoctets;
> > >> > +
> > >> > + gact->current_close_time = ktime_add_ns(gact-
> > >current_close_time,
> > >> > + next->interval);
> > >> > +
> > >> > + close_time = gact->current_close_time;
> > >> > +
> > >> > + if (list_is_last(&next->list, &p->entries))
> > >> > + next = list_first_entry(&p->entries,
> > >> > + struct tcfg_gate_entry, list);
> > >> > + else
> > >> > + next = list_next_entry(next, list);
> > >> > +
> > >> > + now = gate_get_time(gact);
> > >> > +
> > >> > + if (ktime_after(now, close_time)) {
> > >> > + ktime_t cycle, base;
> > >> > + u64 n;
> > >> > +
> > >> > + cycle = p->tcfg_cycletime;
> > >> > + base = ns_to_ktime(p->tcfg_basetime);
> > >> > + n = div64_u64(ktime_sub_ns(now, base), cycle);
> > >> > + close_time = ktime_add_ns(base, (n + 1) * cycle);
> > >> > + }
> > >> > +
> > >> > + rcu_assign_pointer(gact->next_entry, next);
> > >> > + spin_unlock(&gact->entry_lock);
> > >>
> > >> I have couple of question about synchronization here:
> > >>
> > >> - Why do you need next_entry to be rcu pointer? It is only assigned
> > >> here with entry_lock protection and in init code before action is
> > >> visible to concurrent users. I don't see any unlocked rcu-protected
> > >> readers here that could benefit from it.
> > >>
> > >> - Why create dedicated entry_lock instead of using already existing
> > >> per- action tcf_lock?
> > >
> > > Will try to use the tcf_lock for verification.
I think I added entry_lock was that I can't get the tc_action common parameter in this timer function. If I insist to use the tcf_lock, I have to move the hrtimer to struct tcf_gate which has tc_action common.
What do you think?
> > > The thoughts came from that the timer period arrived then check
> > > through the list and then update next time would take much more
> time.
> > > Action function would be busy when traffic. So use a separate lock
> > > here for
> > >
> > >>
> > >> > +
> > >> > + hrtimer_set_expires(&gact->hitimer, close_time);
> > >> > +
> > >> > + return HRTIMER_RESTART;
> > >> > +}
> > >> > +
> > >> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> > >> > + struct tcf_result *res) {
> > >> > + struct tcf_gate *g = to_gate(a);
> > >> > + struct gate_action *gact;
> > >> > + int action;
> > >> > +
> > >> > + tcf_lastuse_update(&g->tcf_tm);
> > >> > + bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> > >> > +
> > >> > + action = READ_ONCE(g->tcf_action);
> > >> > + rcu_read_lock();
> > >>
> > >> Action fastpath is already rcu read lock protected, you don't need
> > >> to manually obtain it.
> > >
> > > Will be removed.
> > >
> > >>
> > >> > + gact = rcu_dereference_bh(g->actg);
> > >> > + if (unlikely(gact->current_gate_status & GATE_ACT_PENDING))
> > >> > + {
> > >>
> > >> Can't current_gate_status be concurrently modified by timer callback?
> > >> This function doesn't use entry_lock to synchronize with timer.
> > >
> > > Will try tcf_lock either.
> > >
> > >>
> > >> > + rcu_read_unlock();
> > >> > + return action;
> > >> > + }
> > >> > +
> > >> > + if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
> > >>
> > >> ...and here
> > >>
> > >> > + goto drop;
> > >> > +
> > >> > + if (gact->current_max_octets >= 0) {
> > >> > + gact->current_entry_octets += qdisc_pkt_len(skb);
> > >> > + if (gact->current_entry_octets >
> > >> > + gact->current_max_octets) {
> > >>
> > >> here also.
> > >>
> > >> > +
> > >> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
> > >>
> > >> Please use tcf_action_inc_overlimit_qstats() and other wrappers for
> > stats.
> > >> Otherwise it will crash if user passes
> > TCA_ACT_FLAGS_NO_PERCPU_STATS
> > >> flag.
> > >
> > > The tcf_action_inc_overlimit_qstats() can't show limit counts in tc
> > > show
> > command. Is there anything need to do?
> >
> > What do you mean? Internally tcf_action_inc_overlimit_qstats() just
> > calls qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:
> >
> >
> > if (likely(a->cpu_qstats)) {
> > qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
> > return;
> > }
> >
> > Is there a subtle bug somewhere in this function?
>
> Sorry, I updated using the tcf_action_*, and the counting is ok. I moved
> back to the qstats_overlimit_inc() because tcf_action_* () include the
> spin_lock(&a->tcfa_lock).
> I would update to tcf_action_* () increate.
>
> >
> > >
> > > Br,
> > > Po Liu
>
> Thanks a lot.
>
> Br,
> Po Liu
Thanks a lot.
Br,
Po Liu
next prev parent reply other threads:[~2020-04-23 9:15 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 12:55 [RFC,net-next 0/9] Introduce a flow gate control action and apply IEEE Po Liu
2020-03-06 12:55 ` [RFC,net-next 1/9] net: qos offload add flow status with dropped count Po Liu
2020-03-06 12:56 ` [RFC,net-next 2/9] net: qos: introduce a gate control flow action Po Liu
2020-03-06 19:11 ` Jakub Kicinski
2020-03-07 6:05 ` [EXT] " Po Liu
2020-03-12 22:14 ` Vinicius Costa Gomes
2020-03-13 3:47 ` [EXT] " Po Liu
2020-03-13 18:36 ` Cong Wang
2020-03-14 4:09 ` [EXT] " Po Liu
2020-03-06 12:56 ` [RFC,net-next 3/9] net: schedule: add action gate offloading Po Liu
2020-03-06 19:02 ` Jakub Kicinski
2020-03-06 19:19 ` Jakub Kicinski
2020-03-07 4:38 ` [EXT] " Po Liu
2020-03-06 12:56 ` [RFC,net-next 4/9] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-03-06 12:56 ` [RFC,net-next 5/9] net: enetc: add tc flower psfp offload driver Po Liu
2020-03-12 22:14 ` Vinicius Costa Gomes
2020-03-13 5:59 ` [EXT] " Po Liu
2020-03-06 12:56 ` [RFC,net-next 6/9] net: qos: add tc police offloading action with max frame size limit Po Liu
2020-06-23 6:34 ` [v1,net-next 1/4] " Po Liu
2020-06-23 6:34 ` [v1,net-next 2/4] net: enetc: add support max frame size for tc flower offload Po Liu
2020-06-23 6:34 ` [v1,net-next 3/4] net: qos: police action add index for tc flower offloading Po Liu
2020-06-23 7:09 ` Ido Schimmel
2020-06-23 7:39 ` [EXT] " Po Liu
2020-06-23 10:08 ` Jamal Hadi Salim
2020-06-23 6:34 ` [v1,net-next 4/4] net: enetc add tc flower offload flow metering policing action Po Liu
2020-06-23 14:54 ` kernel test robot
2020-06-23 15:08 ` kernel test robot
2020-06-24 9:36 ` [v2,net-next 1/4] net: qos: add tc police offloading action with max frame size limit Po Liu
2020-06-24 9:36 ` [v2,net-next 2/4] net: enetc: add support max frame size for tc flower offload Po Liu
2020-06-25 5:04 ` David Miller
2020-06-24 9:36 ` [v2,net-next 3/4] net: qos: police action add index for tc flower offloading Po Liu
2020-06-25 5:04 ` David Miller
2020-06-24 9:36 ` [v2,net-next 4/4] net: enetc add tc flower offload flow metering policing action Po Liu
2020-06-25 5:04 ` David Miller
2020-06-25 5:04 ` [v2,net-next 1/4] net: qos: add tc police offloading action with max frame size limit David Miller
2020-06-23 7:01 ` [v1,net-next " Ido Schimmel
2020-03-06 12:56 ` [RFC,net-next 7/9] net: enetc: add support max frame size for tc flower offload Po Liu
2020-03-06 12:56 ` [RFC,net-next 8/9] net: qos: police action add index for tc flower offloading Po Liu
2020-06-21 10:04 ` Ido Schimmel
2020-03-06 12:56 ` [RFC,net-next 9/9] net: enetc add tc flower offload flow metering policing action Po Liu
2020-03-06 12:56 ` [RFC, iproute2-next] iproute2:tc:action: add a gate control action Po Liu
2020-03-24 3:47 ` [v1,net-next 0/5] Introduce a flow gate control action and apply IEEE Po Liu
2020-03-24 3:47 ` [v1,net-next 1/5] net: qos offload add flow status with dropped count Po Liu
2020-03-24 10:01 ` Jiri Pirko
2020-03-24 13:04 ` [EXT] " Po Liu
2020-03-24 3:47 ` [v1,net-next 2/5] net: qos: introduce a gate control flow action Po Liu
2020-03-24 10:19 ` Jiri Pirko
2020-03-24 10:28 ` [EXT] " Po Liu
2020-03-24 3:47 ` [v1,net-next 3/5] net: schedule: add action gate offloading Po Liu
2020-03-24 3:47 ` [v1,net-next 4/5] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-03-24 11:18 ` kbuild test robot
2020-03-24 12:14 ` Jiri Pirko
2020-03-24 3:47 ` [v1,net-next 5/5] net: enetc: add tc flower psfp offload driver Po Liu
2020-03-24 12:53 ` kbuild test robot
2020-03-24 3:47 ` [v1,iproute2 1/2] iproute2:tc:action: add a gate control action Po Liu
2020-03-24 21:59 ` Stephen Hemminger
2020-03-25 2:40 ` [EXT] " Po Liu
2020-03-24 3:47 ` [v1,iproute2 2/2] iproute2: add gate action man page Po Liu
2020-04-14 5:40 ` [v2,net-next 0/4] Introduce a flow gate control action and apply IEEE Po Liu
2020-04-14 5:40 ` [ v2,net-next 1/4] net: qos: introduce a gate control flow action Po Liu
2020-04-14 5:40 ` [ v2,net-next 2/4] net: schedule: add action gate offloading Po Liu
2020-04-14 5:40 ` [ v2,net-next 3/4] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-04-14 5:40 ` [ v2,net-next 4/4] net: enetc: add tc flower psfp offload driver Po Liu
2020-04-14 23:41 ` [v2,net-next 0/4] Introduce a flow gate control action and apply IEEE David Miller
2020-04-18 1:12 ` Po Liu
2020-04-18 1:12 ` [ v2,net-next 1/4] net: qos: introduce a gate control flow action Po Liu
2020-04-18 1:12 ` [ v2,net-next 2/4] net: schedule: add action gate offloading Po Liu
2020-04-18 1:12 ` [ v2,net-next 3/4] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-04-18 1:12 ` [ v2,net-next 4/4] net: enetc: add tc flower psfp offload driver Po Liu
2020-04-18 22:52 ` Vladimir Oltean
2020-04-19 1:44 ` [EXT] " Po Liu
2020-04-22 2:48 ` [v3,net-next 0/4] Introduce a flow gate control action and apply IEEE Po Liu
2020-04-22 2:48 ` [v3,net-next 1/4] net: qos: introduce a gate control flow action Po Liu
2020-04-22 13:23 ` Vlad Buslov
2020-04-23 3:14 ` [EXT] " Po Liu
2020-04-23 7:43 ` Vlad Buslov
2020-04-23 8:32 ` Po Liu
2020-04-23 9:15 ` Po Liu [this message]
2020-04-23 11:14 ` Vlad Buslov
2020-04-23 11:03 ` Vlad Buslov
2020-04-22 19:19 ` Allan W. Nielsen
2020-04-22 19:28 ` Vladimir Oltean
2020-04-22 20:05 ` Dave Taht
2020-04-23 3:29 ` [EXT] " Po Liu
2020-04-23 19:11 ` Allan W. Nielsen
2020-04-23 3:27 ` [EXT] " Po Liu
2020-04-23 17:38 ` Vinicius Costa Gomes
2020-04-23 19:17 ` Allan W. Nielsen
2020-04-24 3:23 ` [EXT] " Po Liu
2020-04-24 17:41 ` Vinicius Costa Gomes
2020-04-25 1:49 ` Po Liu
2020-04-22 2:48 ` [v3,net-next 2/4] net: schedule: add action gate offloading Po Liu
2020-04-22 14:14 ` Vlad Buslov
2020-04-22 2:48 ` [v3,net-next 3/4] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-04-22 2:48 ` [v3,net-next 4/4] net: enetc: add tc flower psfp offload driver Po Liu
2020-04-28 3:34 ` [v4,net-next 0/4] Introduce a flow gate control action and apply IEEE Po Liu
2020-04-28 3:34 ` [v4,net-next 1/4] net: qos: introduce a gate control flow action Po Liu
2020-04-29 17:04 ` Vlad Buslov
2020-04-30 0:52 ` [EXT] " Po Liu
2020-04-28 3:34 ` [v4,net-next 2/4] net: schedule: add action gate offloading Po Liu
2020-04-29 17:40 ` Vlad Buslov
2020-04-28 3:34 ` [v4,net-next 3/4] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-04-28 3:34 ` [v4,net-next 4/4] net: enetc: add tc flower psfp offload driver Po Liu
2020-05-01 0:53 ` [v5,net-next 0/4] Introduce a flow gate control action and apply IEEE Po Liu
2020-05-01 0:53 ` [v5,net-next 1/4] net: qos: introduce a gate control flow action Po Liu
2020-05-01 0:53 ` [v5,net-next 2/4] net: schedule: add action gate offloading Po Liu
2020-05-01 0:53 ` [v5,net-next 3/4] net: enetc: add hw tc hw offload features for PSPF capability Po Liu
2020-05-01 0:53 ` [v5,net-next 4/4] net: enetc: add tc flower psfp offload driver Po Liu
2020-05-03 6:32 ` [v3,iproute2 1/2] iproute2:tc:action: add a gate control action Po Liu
2020-05-03 6:32 ` [v3,iproute2 2/2] iproute2: add gate action man page Po Liu
2020-05-06 8:40 ` [v4,iproute2-next 1/2] iproute2-next:tc:action: add a gate control action Po Liu
2020-05-06 8:40 ` [v4,iproute2-next 2/2] iproute2-next: add gate action man page Po Liu
2020-05-08 7:02 ` [v5,iproute2-next 1/2] iproute2-next:tc:action: add a gate control action Po Liu
2020-05-08 7:02 ` [v5,iproute2-next 2/2] iproute2-next: add gate action man page Po Liu
2020-05-13 2:21 ` [v5,iproute2-next 1/2] iproute2-next:tc:action: add a gate control action David Ahern
2020-05-06 12:54 ` [v4,iproute2-next " Davide Caratti
2020-05-07 2:28 ` [EXT] " Po Liu
2020-05-06 15:21 ` Stephen Hemminger
2020-05-05 0:05 ` [v3,iproute2 1/2] iproute2:tc:action: " Stephen Hemminger
2020-05-05 0:06 ` Stephen Hemminger
2020-05-01 23:08 ` [v5,net-next 0/4] Introduce a flow gate control action and apply IEEE David Miller
2020-06-19 6:01 ` [v2,net-next] net: qos offload add flow status with dropped count Po Liu
2020-06-19 7:03 ` Simon Horman
2020-06-19 18:00 ` Vlad Buslov
2020-06-19 19:54 ` David Miller
2020-04-25 8:56 Re: [v3,net-next 1/4] net: qos: introduce a gate control flow action Po Liu
2020-04-27 6:58 ` Vlad Buslov
2020-04-27 9:27 ` [EXT] " Po Liu
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