[PATCH net-next] net/sched: do not reset queues in graft operations
From: Eric Dumazet <edumazet@google.com>
Date: 2026-03-06 11:34:05
Subsystem:
cbs/etf/taprio qdiscs, networking [general], tc subsystem, the rest · Maintainers:
Vinicius Costa Gomes, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
Following typical script is extremely disruptive, because each graft operation calls dev_deactivate() which resets all the queues of the device. QPARAM="limit 100000 flow_limit 1000 buckets 4096" TXQS=64 for ETH in eth1 do tc qd del dev $ETH root 2>/dev/null tc qd add dev $ETH root handle 1: mq for i in `seq 1 $TXQS` do slot=$( printf %x $(( i )) ) tc qd add dev $ETH parent 1:$slot fq $QPARAM done done One can add "ip link set dev $ETH down/up" to reduce the disruption time: QPARAM="limit 100000 flow_limit 1000 buckets 4096" TXQS=64 for ETH in eth1 do ip link set dev $ETH down tc qd del dev $ETH root 2>/dev/null tc qd add dev $ETH root handle 1: mq for i in `seq 1 $TXQS` do slot=$( printf %x $(( i )) ) tc qd add dev $ETH parent 1:$slot fq $QPARAM done ip link set dev $ETH up done Or we can add a @reset_needed flag to dev_deactivate() and dev_deactivate_many(). This flag is set to true at device dismantle or linkwatch_do_dev(), and to false for graft operations. In the future, we might only stop one queue instead of the whole device, ie call dev_deactivate_queue() instead of dev_deactivate(). Signed-off-by: Eric Dumazet <edumazet@google.com> --- include/net/sch_generic.h | 4 ++-- net/core/dev.c | 2 +- net/core/link_watch.c | 2 +- net/sched/sch_api.c | 2 +- net/sched/sch_generic.c | 19 +++++++++++-------- net/sched/sch_htb.c | 4 ++-- net/sched/sch_mq.c | 2 +- net/sched/sch_mqprio.c | 2 +- net/sched/sch_taprio.c | 2 +- 9 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index c355300893a3921740cf6b919cc58de953cd610c..16beba40914ee5a9454f9eec2ad6e600543c89f2 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h@@ -710,8 +710,8 @@ void dev_qdisc_change_real_num_tx(struct net_device *dev, void dev_init_scheduler(struct net_device *dev); void dev_shutdown(struct net_device *dev); void dev_activate(struct net_device *dev); -void dev_deactivate(struct net_device *dev); -void dev_deactivate_many(struct list_head *head); +void dev_deactivate(struct net_device *dev, bool reset_needed); +void dev_deactivate_many(struct list_head *head, bool reset_needed); struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue, struct Qdisc *qdisc); void qdisc_reset(struct Qdisc *qdisc);
diff --git a/net/core/dev.c b/net/core/dev.c
index 203dc36aaed55e706f5d978ec02c6bf48201e3d4..6fc9350f0be8756ae849d5b0ca9b222055d96ced 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -1756,7 +1756,7 @@ static void __dev_close_many(struct list_head *head) smp_mb__after_atomic(); /* Commit netif_running(). */ } - dev_deactivate_many(head); + dev_deactivate_many(head, true); list_for_each_entry(dev, head, close_list) { const struct net_device_ops *ops = dev->netdev_ops;
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index 25c455c10a01cf535d6a7d2952d51434fe462690..ff2c1d4538efbc89cd49d8d8477542a6e7bacbad 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c@@ -181,7 +181,7 @@ static void linkwatch_do_dev(struct net_device *dev) if (netif_carrier_ok(dev)) dev_activate(dev); else - dev_deactivate(dev); + dev_deactivate(dev, true); netif_state_change(dev); }
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index cc43e3f7574fae203989f5c28b4934f0720e64c2..c0bab092ea809955b3a5aaa08c169bca55cfaf7f 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c@@ -1120,7 +1120,7 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent, } if (dev->flags & IFF_UP) - dev_deactivate(dev); + dev_deactivate(dev, false); qdisc_offload_graft_root(dev, new, old, extack);
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 556e0d8003161d3dfe68e484f6349714cf989c0c..55e17f9e5636f2d9e798889ff59b2f69c9c1709c 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c@@ -1374,7 +1374,7 @@ static bool some_qdisc_is_busy(struct net_device *dev) * This function returns only when all outstanding transmissions * have completed, unless all devices are in dismantle phase. */ -void dev_deactivate_many(struct list_head *head) +void dev_deactivate_many(struct list_head *head, bool reset_needed) { bool sync_needed = false; struct net_device *dev;
@@ -1393,11 +1393,14 @@ void dev_deactivate_many(struct list_head *head) if (sync_needed) synchronize_net(); - list_for_each_entry(dev, head, close_list) { - netdev_for_each_tx_queue(dev, dev_reset_queue, NULL); + if (reset_needed) { + list_for_each_entry(dev, head, close_list) { + netdev_for_each_tx_queue(dev, dev_reset_queue, NULL); - if (dev_ingress_queue(dev)) - dev_reset_queue(dev, dev_ingress_queue(dev), NULL); + if (dev_ingress_queue(dev)) + dev_reset_queue(dev, dev_ingress_queue(dev), + NULL); + } } /* Wait for outstanding qdisc_run calls. */
@@ -1412,12 +1415,12 @@ void dev_deactivate_many(struct list_head *head) } } -void dev_deactivate(struct net_device *dev) +void dev_deactivate(struct net_device *dev, bool reset_needed) { LIST_HEAD(single); list_add(&dev->close_list, &single); - dev_deactivate_many(&single); + dev_deactivate_many(&single, reset_needed); list_del(&single); } EXPORT_SYMBOL(dev_deactivate);
@@ -1473,7 +1476,7 @@ int dev_qdisc_change_tx_queue_len(struct net_device *dev) int ret = 0; if (up) - dev_deactivate(dev); + dev_deactivate(dev, false); for (i = 0; i < dev->num_tx_queues; i++) { ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index cf6cd4ccfa2029d9a45e35d6780520290690732d..eb12381795ce1bb0f3b8c5f502e16ad64c4408c8 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c@@ -1387,7 +1387,7 @@ htb_graft_helper(struct netdev_queue *dev_queue, struct Qdisc *new_q) struct Qdisc *old_q; if (dev->flags & IFF_UP) - dev_deactivate(dev); + dev_deactivate(dev, false); old_q = dev_graft_qdisc(dev_queue, new_q); if (new_q) new_q->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
@@ -1421,7 +1421,7 @@ static void htb_offload_move_qdisc(struct Qdisc *sch, struct htb_class *cl_old, struct Qdisc *qdisc; if (dev->flags & IFF_UP) - dev_deactivate(dev); + dev_deactivate(dev, false); qdisc = dev_graft_qdisc(queue_old, NULL); WARN_ON(qdisc != cl_old->leaf.q); }
diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c
index 0ed199fa18f04a06197116b6ab64ff3647dbace9..a0133a7b9d3b09a0d2a6064234c8fdef60dbf955 100644
--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c@@ -201,7 +201,7 @@ static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, struct net_device *dev = qdisc_dev(sch); if (dev->flags & IFF_UP) - dev_deactivate(dev); + dev_deactivate(dev, false); *old = dev_graft_qdisc(dev_queue, new); if (new)
diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c
index b83276409416fabeccc441e5127211632ddcfedb..002add5ce9e0ab04a6260495d1bec02983c2a204 100644
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c@@ -469,7 +469,7 @@ static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, return -EINVAL; if (dev->flags & IFF_UP) - dev_deactivate(dev); + dev_deactivate(dev, false); *old = dev_graft_qdisc(dev_queue, new);
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index f721c03514f6008ecc59fe4c4ca4a082099dc125..8e375281195061da848fb2bfaf79cf125afccac0 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c@@ -2184,7 +2184,7 @@ static int taprio_graft(struct Qdisc *sch, unsigned long cl, return -EINVAL; if (dev->flags & IFF_UP) - dev_deactivate(dev); + dev_deactivate(dev, false); /* In offload mode, the child Qdisc is directly attached to the netdev * TX queue, and thus, we need to keep its refcount elevated in order
--
2.53.0.473.g4a7958ca14-goog