Re: [ovs-dev] [PATCH net-next v2 2/9] net: sched: act_sample: add action cookie to sample
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
>>> ---
>>> 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.
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Re: [ovs-dev] [PATCH net-next v2 2/9] net: sched: act_sample: add action cookie to sample
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
> > ---
> > 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(>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, );
> >
>
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Re: [ovs-dev] [PATCH net-next v2 2/9] net: sched: act_sample: add action cookie to sample
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
> ---
> 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(>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, );
>
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Re: [ovs-dev] [PATCH net-next v2 2/9] net: sched: act_sample: add action cookie to sample
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 Reviewed-by: Simon Horman ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
[ovs-dev] [PATCH net-next v2 2/9] net: sched: act_sample: add action cookie to sample
If the action has a user_cookie, pass it along to the sample so it can
be easily identified.
Signed-off-by: Adrian Moreno
---
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] = {};
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(>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, );
--
2.45.1
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