[PATCH net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided

[PATCH net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided

[Eric Dumazet]

"tc qdisc show ... handle xxx" filtering can be done by the kernel.

A followup patch can do the same for tcm_parent.

iproute2/tc needs a small companion patch.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_api.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index dd0edc9bd4610ec865fc97a81f801a7da020667b..6f7847c5536f16e6754954f0a606581e17257361 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -979,13 +979,17 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
 	return -EMSGSIZE;
 }
 
-static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
+static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible,
+				 const struct tcmsg *tcm)
 {
 	if (q->flags & TCQ_F_BUILTIN)
 		return true;
 	if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
 		return true;
-
+	if (tcm) {
+		if (tcm->tcm_handle && tcm->tcm_handle != q->handle)
+			return true;
+	}
 	return false;
 }
 
@@ -1000,7 +1004,7 @@ static int qdisc_get_notify(struct net *net, struct sk_buff *oskb,
 	if (!skb)
 		return -ENOBUFS;
 
-	if (!tc_qdisc_dump_ignore(q, false)) {
+	if (!tc_qdisc_dump_ignore(q, false, NULL)) {
 		if (tc_fill_qdisc(skb, q, clid, portid, n->nlmsg_seq, 0,
 				  RTM_NEWQDISC, extack) < 0)
 			goto err_out;
@@ -1030,12 +1034,12 @@ static int qdisc_notify(struct net *net, struct sk_buff *oskb,
 	if (!skb)
 		return -ENOBUFS;
 
-	if (old && !tc_qdisc_dump_ignore(old, false)) {
+	if (old && !tc_qdisc_dump_ignore(old, false, NULL)) {
 		if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
 				  0, RTM_DELQDISC, extack) < 0)
 			goto err_out;
 	}
-	if (new && !tc_qdisc_dump_ignore(new, false)) {
+	if (new && !tc_qdisc_dump_ignore(new, false, NULL)) {
 		if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
 				  old ? NLM_F_REPLACE : 0, RTM_NEWQDISC, extack) < 0)
 			goto err_out;
@@ -1825,21 +1829,24 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
 			      int *q_idx_p, int s_q_idx, bool recur,
 			      bool dump_invisible)
 {
+	const struct nlmsghdr *nlh = cb->nlh;
 	int ret = 0, q_idx = *q_idx_p;
+	const struct tcmsg *tcm;
 	struct Qdisc *q;
 	int b;
 
 	if (!root)
 		return 0;
 
+	tcm = nlmsg_data(nlh);
 	q = root;
 	if (q_idx < s_q_idx) {
 		q_idx++;
 	} else {
-		if (!tc_qdisc_dump_ignore(q, dump_invisible))
+		if (!tc_qdisc_dump_ignore(q, dump_invisible, tcm))
 		    ret = tc_fill_qdisc(skb, q, q->parent,
 					NETLINK_CB(cb->skb).portid,
-					cb->nlh->nlmsg_seq, NLM_F_MULTI,
+					nlh->nlmsg_seq, NLM_F_MULTI,
 					RTM_NEWQDISC, NULL);
 		if (ret < 0)
 			goto out;
@@ -1860,10 +1867,10 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
 			q_idx++;
 			continue;
 		}
-		if (!tc_qdisc_dump_ignore(q, dump_invisible))
+		if (!tc_qdisc_dump_ignore(q, dump_invisible, tcm))
 			ret = tc_fill_qdisc(skb, q, q->parent,
 					    NETLINK_CB(cb->skb).portid,
-					    cb->nlh->nlmsg_seq, NLM_F_MULTI,
+					    nlh->nlmsg_seq, NLM_F_MULTI,
 					    RTM_NEWQDISC, NULL);
 		if (ret < 0)
 			goto out;
@@ -2341,7 +2348,7 @@ static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
 {
 	struct qdisc_dump_args arg;
 
-	if (tc_qdisc_dump_ignore(q, false) ||
+	if (tc_qdisc_dump_ignore(q, false, NULL) ||
 	    *t_p < s_t || !q->ops->cl_ops ||
 	    (tcm->tcm_parent &&
 	     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
-- 
2.54.0.545.g6539524ca2-goog

Re: [PATCH net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided

[Jamal Hadi Salim]

On Sun, May 3, 2026 at 7:45 AM Eric Dumazet <edumazet@google.com> wrote:
>
> "tc qdisc show ... handle xxx" filtering can be done by the kernel.
>
> A followup patch can do the same for tcm_parent.
>
> iproute2/tc needs a small companion patch.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

If you ever redo this for whatever reason, showing the dump of before
and after will be good documentation.

Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>

cheers,
jamal

> ---
>  net/sched/sch_api.c | 27 +++++++++++++++++----------
>  1 file changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
> index dd0edc9bd4610ec865fc97a81f801a7da020667b..6f7847c5536f16e6754954f0a606581e17257361 100644
> --- a/net/sched/sch_api.c
> +++ b/net/sched/sch_api.c
> @@ -979,13 +979,17 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
>         return -EMSGSIZE;
>  }
>
> -static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
> +static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible,
> +                                const struct tcmsg *tcm)
>  {
>         if (q->flags & TCQ_F_BUILTIN)
>                 return true;
>         if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
>                 return true;
> -
> +       if (tcm) {
> +               if (tcm->tcm_handle && tcm->tcm_handle != q->handle)
> +                       return true;
> +       }
>         return false;
>  }
>
> @@ -1000,7 +1004,7 @@ static int qdisc_get_notify(struct net *net, struct sk_buff *oskb,
>         if (!skb)
>                 return -ENOBUFS;
>
> -       if (!tc_qdisc_dump_ignore(q, false)) {
> +       if (!tc_qdisc_dump_ignore(q, false, NULL)) {
>                 if (tc_fill_qdisc(skb, q, clid, portid, n->nlmsg_seq, 0,
>                                   RTM_NEWQDISC, extack) < 0)
>                         goto err_out;
> @@ -1030,12 +1034,12 @@ static int qdisc_notify(struct net *net, struct sk_buff *oskb,
>         if (!skb)
>                 return -ENOBUFS;
>
> -       if (old && !tc_qdisc_dump_ignore(old, false)) {
> +       if (old && !tc_qdisc_dump_ignore(old, false, NULL)) {
>                 if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
>                                   0, RTM_DELQDISC, extack) < 0)
>                         goto err_out;
>         }
> -       if (new && !tc_qdisc_dump_ignore(new, false)) {
> +       if (new && !tc_qdisc_dump_ignore(new, false, NULL)) {
>                 if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
>                                   old ? NLM_F_REPLACE : 0, RTM_NEWQDISC, extack) < 0)
>                         goto err_out;
> @@ -1825,21 +1829,24 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
>                               int *q_idx_p, int s_q_idx, bool recur,
>                               bool dump_invisible)
>  {
> +       const struct nlmsghdr *nlh = cb->nlh;
>         int ret = 0, q_idx = *q_idx_p;
> +       const struct tcmsg *tcm;
>         struct Qdisc *q;
>         int b;
>
>         if (!root)
>                 return 0;
>
> +       tcm = nlmsg_data(nlh);
>         q = root;
>         if (q_idx < s_q_idx) {
>                 q_idx++;
>         } else {
> -               if (!tc_qdisc_dump_ignore(q, dump_invisible))
> +               if (!tc_qdisc_dump_ignore(q, dump_invisible, tcm))
>                     ret = tc_fill_qdisc(skb, q, q->parent,
>                                         NETLINK_CB(cb->skb).portid,
> -                                       cb->nlh->nlmsg_seq, NLM_F_MULTI,
> +                                       nlh->nlmsg_seq, NLM_F_MULTI,
>                                         RTM_NEWQDISC, NULL);
>                 if (ret < 0)
>                         goto out;
> @@ -1860,10 +1867,10 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
>                         q_idx++;
>                         continue;
>                 }
> -               if (!tc_qdisc_dump_ignore(q, dump_invisible))
> +               if (!tc_qdisc_dump_ignore(q, dump_invisible, tcm))
>                         ret = tc_fill_qdisc(skb, q, q->parent,
>                                             NETLINK_CB(cb->skb).portid,
> -                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
> +                                           nlh->nlmsg_seq, NLM_F_MULTI,
>                                             RTM_NEWQDISC, NULL);
>                 if (ret < 0)
>                         goto out;
> @@ -2341,7 +2348,7 @@ static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
>  {
>         struct qdisc_dump_args arg;
>
> -       if (tc_qdisc_dump_ignore(q, false) ||
> +       if (tc_qdisc_dump_ignore(q, false, NULL) ||
>             *t_p < s_t || !q->ops->cl_ops ||
>             (tcm->tcm_parent &&
>              TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
> --
> 2.54.0.545.g6539524ca2-goog
>

Re: [PATCH net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided

[Eric Dumazet]

On Mon, May 4, 2026 at 12:13 PM Jamal Hadi Salim <jhs@mojatatu.com> wrote:
>
> On Sun, May 3, 2026 at 7:45 AM Eric Dumazet <edumazet@google.com> wrote:
> >
> > "tc qdisc show ... handle xxx" filtering can be done by the kernel.
> >
> > A followup patch can do the same for tcm_parent.
> >
> > iproute2/tc needs a small companion patch.
> >
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
>
> If you ever redo this for whatever reason, showing the dump of before
> and after will be good documentation.

There is no difference in tc output.

 One can use strace and look at all the recvmsg() values, but they are
quite verbose :/

Re: [PATCH net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided

[Jamal Hadi Salim]

On Mon, May 4, 2026 at 3:20 PM Eric Dumazet <edumazet@google.com> wrote:
>
> On Mon, May 4, 2026 at 12:13 PM Jamal Hadi Salim <jhs@mojatatu.com> wrote:
> >
> > On Sun, May 3, 2026 at 7:45 AM Eric Dumazet <edumazet@google.com> wrote:
> > >
> > > "tc qdisc show ... handle xxx" filtering can be done by the kernel.
> > >
> > > A followup patch can do the same for tcm_parent.
> > >
> > > iproute2/tc needs a small companion patch.
> > >
> > > Signed-off-by: Eric Dumazet <edumazet@google.com>
> >
> > If you ever redo this for whatever reason, showing the dump of before
> > and after will be good documentation.
>
> There is no difference in tc output.
>
>  One can use strace and look at all the recvmsg() values, but they are
> quite verbose :/

Ah, i see it now ;->

cheers,
jamal

Re: [PATCH net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sun,  3 May 2026 11:45:15 +0000 you wrote:
> "tc qdisc show ... handle xxx" filtering can be done by the kernel.
> 
> A followup patch can do the same for tcm_parent.
> 
> iproute2/tc needs a small companion patch.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> 
> [...]

Here is the summary with links:
  - [net-next] net/sched: speedup tc_dump_qdisc() when tcm_handle is provided
    https://git.kernel.org/netdev/net-next/c/c1e5127b577c

You are awesome, thank you!
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