| Message ID | 20240603185647.2310748-3-amorenoz@redhat.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: openvswitch: Add sample multicasting. | expand |
On Mon, Jun 03, 2024 at 08:56:36PM +0200, Adrian Moreno wrote: > If the action has a user_cookie, pass it along to the sample so it can > be easily identified. > > Signed-off-by: Adrian Moreno <amorenoz@redhat.com> Reviewed-by: Simon Horman <horms@kernel.org>
On 6/3/24 20:56, Adrian Moreno wrote: > If the action has a user_cookie, pass it along to the sample so it can > be easily identified. > > Signed-off-by: Adrian Moreno <amorenoz@redhat.com> > --- > net/sched/act_sample.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c > index a69b53d54039..5c3f86ec964a 100644 > --- a/net/sched/act_sample.c > +++ b/net/sched/act_sample.c > @@ -165,9 +165,11 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, > const struct tc_action *a, > struct tcf_result *res) > { > + u8 cookie_data[TC_COOKIE_MAX_SIZE] = {}; Is it necessary to initialize these 16 bytes on every call? Might be expensive. We're passing the data length around, so the uninitialized parts should not be accessed. Best regards, Ilya Maximets. > struct tcf_sample *s = to_sample(a); > struct psample_group *psample_group; > struct psample_metadata md = {}; > + struct tc_cookie *user_cookie; > int retval; > > tcf_lastuse_update(&s->tcf_tm); > @@ -189,6 +191,16 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, > if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) > skb_push(skb, skb->mac_len); > > + rcu_read_lock(); > + user_cookie = rcu_dereference(a->user_cookie); > + if (user_cookie) { > + memcpy(cookie_data, user_cookie->data, > + user_cookie->len); > + md.user_cookie = cookie_data; > + md.user_cookie_len = user_cookie->len; > + } > + rcu_read_unlock(); > + > md.trunc_size = s->truncate ? s->trunc_size : skb->len; > psample_sample_packet(psample_group, skb, s->rate, &md); >
On Mon, Jun 17, 2024 at 12:00:04PM GMT, Ilya Maximets wrote: > On 6/3/24 20:56, Adrian Moreno wrote: > > If the action has a user_cookie, pass it along to the sample so it can > > be easily identified. > > > > Signed-off-by: Adrian Moreno <amorenoz@redhat.com> > > --- > > net/sched/act_sample.c | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > > diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c > > index a69b53d54039..5c3f86ec964a 100644 > > --- a/net/sched/act_sample.c > > +++ b/net/sched/act_sample.c > > @@ -165,9 +165,11 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, > > const struct tc_action *a, > > struct tcf_result *res) > > { > > + u8 cookie_data[TC_COOKIE_MAX_SIZE] = {}; > > Is it necessary to initialize these 16 bytes on every call? > Might be expensive. We're passing the data length around, > so the uninitialized parts should not be accessed. > They "should" not, indeed. I was just trying to be extra careful. Are you worried TC_COOKIE_MAX_SIZE could grow or the cycles needed to clear the current 16 bytes? > Best regards, Ilya Maximets. > > > struct tcf_sample *s = to_sample(a); > > struct psample_group *psample_group; > > struct psample_metadata md = {}; > > + struct tc_cookie *user_cookie; > > int retval; > > > > tcf_lastuse_update(&s->tcf_tm); > > @@ -189,6 +191,16 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, > > if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) > > skb_push(skb, skb->mac_len); > > > > + rcu_read_lock(); > > + user_cookie = rcu_dereference(a->user_cookie); > > + if (user_cookie) { > > + memcpy(cookie_data, user_cookie->data, > > + user_cookie->len); > > + md.user_cookie = cookie_data; > > + md.user_cookie_len = user_cookie->len; > > + } > > + rcu_read_unlock(); > > + > > md.trunc_size = s->truncate ? s->trunc_size : skb->len; > > psample_sample_packet(psample_group, skb, s->rate, &md); > > >
On 6/18/24 09:38, Adrián Moreno wrote: > On Mon, Jun 17, 2024 at 12:00:04PM GMT, Ilya Maximets wrote: >> On 6/3/24 20:56, Adrian Moreno wrote: >>> If the action has a user_cookie, pass it along to the sample so it can >>> be easily identified. >>> >>> Signed-off-by: Adrian Moreno <amorenoz@redhat.com> >>> --- >>> net/sched/act_sample.c | 12 ++++++++++++ >>> 1 file changed, 12 insertions(+) >>> >>> diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c >>> index a69b53d54039..5c3f86ec964a 100644 >>> --- a/net/sched/act_sample.c >>> +++ b/net/sched/act_sample.c >>> @@ -165,9 +165,11 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, >>> const struct tc_action *a, >>> struct tcf_result *res) >>> { >>> + u8 cookie_data[TC_COOKIE_MAX_SIZE] = {}; >> >> Is it necessary to initialize these 16 bytes on every call? >> Might be expensive. We're passing the data length around, >> so the uninitialized parts should not be accessed. >> > > They "should" not, indeed. I was just trying to be extra careful. > Are you worried TC_COOKIE_MAX_SIZE could grow or the cycles needed to > clear the current 16 bytes? I'm assuming that any extra cycles spent per packet are undesirable, so should be avoided, if possible. Even if we save 1-2 cycles per packet, it's a lot when we talk about millions of packets per second. In this particular case, it seems, we do not sacrifice anything, so it's just a couple of cycles back for free. Best regards, Ilya Maximets.
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c index a69b53d54039..5c3f86ec964a 100644 --- a/net/sched/act_sample.c +++ b/net/sched/act_sample.c @@ -165,9 +165,11 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, struct tcf_result *res) { + u8 cookie_data[TC_COOKIE_MAX_SIZE] = {}; struct tcf_sample *s = to_sample(a); struct psample_group *psample_group; struct psample_metadata md = {}; + struct tc_cookie *user_cookie; int retval; tcf_lastuse_update(&s->tcf_tm); @@ -189,6 +191,16 @@ TC_INDIRECT_SCOPE int tcf_sample_act(struct sk_buff *skb, if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) skb_push(skb, skb->mac_len); + rcu_read_lock(); + user_cookie = rcu_dereference(a->user_cookie); + if (user_cookie) { + memcpy(cookie_data, user_cookie->data, + user_cookie->len); + md.user_cookie = cookie_data; + md.user_cookie_len = user_cookie->len; + } + rcu_read_unlock(); + md.trunc_size = s->truncate ? s->trunc_size : skb->len; psample_sample_packet(psample_group, skb, s->rate, &md);
If the action has a user_cookie, pass it along to the sample so it can be easily identified. Signed-off-by: Adrian Moreno <amorenoz@redhat.com> --- net/sched/act_sample.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)