From: Wei Hu <weh@linux.microsoft.com>
To: longli@kernel.org, kotaranov@microsoft.com, kuba@kernel.org,
davem@davemloft.net, pabeni@redhat.com, edumazet@google.com,
andrew+netdev@lunn.ch, jgg@ziepe.ca, leon@kernel.org,
haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
shradhagupta@linux.microsoft.com, horms@kernel.org,
ernis@linux.microsoft.com, stephen@networkplumber.org
Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
dipayanroy@linux.microsoft.com, bpf@vger.kernel.org,
sdf@fomichev.me, daniel@iogearbox.net, hawk@kernel.org,
ast@kernel.org, john.fastabend@gmail.com, weh@microsoft.com
Subject: [PATCH net-next v6 12/13] net: mana: keep the surviving queues when the channel count is reduced
Date: Fri, 9 Oct 2026 14:41:23 +0000 [thread overview]
Message-ID: <6cd5cbe37973685f58b5cc54a598f3df8ac48e52.1790795005.git.weh@linux.microsoft.com> (raw)
In-Reply-To: <cover.1790795005.git.weh@linux.microsoft.com>
From: Long Li <longli@microsoft.com>
Split the live set into a kept prefix and a retiring tail. Reductions
allocate only pointer arrays and steering tables, retaining the kept
queues' page pools, buffers, NAPI state and XDP references.
After publication, wait for TX-selection readers before freeing the old
containers, then retire only the tail. Failed publication discards the
new containers without freeing shared queues.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Wei Hu <weh@microsoft.com>
---
drivers/net/ethernet/microsoft/mana/mana_en.c | 112 +++++++++++++++++-
.../ethernet/microsoft/mana/mana_ethtool.c | 30 +++++
include/net/mana/mana.h | 4 +
3 files changed, 143 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 5619c6a763c2..2fe53adda119 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -4149,6 +4149,114 @@ void mana_qset_scratch_free(struct mana_port_context *scratch)
kvfree(scratch);
}
+/* Split into kept queues and a retiring tail without changing live ownership.
+ * Queue i retains EQ i.
+ */
+int mana_split_qset(struct mana_port_context *apc,
+ struct mana_port_context *scratch, unsigned int new_count,
+ struct mana_qset *out_new, struct mana_qset *out_tail)
+{
+ unsigned int old_count = apc->num_queues;
+ struct mana_tx_qp **new_tx, **tail_tx;
+ struct mana_rxq **new_rx, **tail_rx;
+ unsigned int tail_count;
+ bool indir_lost;
+ unsigned int i;
+ int err;
+
+ ASSERT_RTNL();
+
+ if (WARN_ON(new_count == 0 || new_count >= old_count))
+ return -EINVAL;
+ if (WARN_ON(!apc->tx_qp || !apc->rxqs))
+ return -EINVAL;
+
+ tail_count = old_count - new_count;
+
+ /* Build steering separately so it cannot index beyond the shortened RX
+ * array.
+ */
+ scratch->num_queues = new_count;
+ err = mana_rss_table_alloc(scratch);
+ if (err)
+ return err;
+
+ if (mana_rss_table_keep(apc, new_count, &indir_lost))
+ memcpy(scratch->indir_table, apc->indir_table,
+ apc->indir_table_sz * sizeof(*apc->indir_table));
+ else
+ mana_rss_table_init(scratch);
+
+ new_tx = kzalloc_objs(struct mana_tx_qp *, new_count);
+ new_rx = kzalloc_objs(struct mana_rxq *, new_count);
+ tail_tx = kzalloc_objs(struct mana_tx_qp *, tail_count);
+ tail_rx = kzalloc_objs(struct mana_rxq *, tail_count);
+ if (!new_tx || !new_rx || !tail_tx || !tail_rx) {
+ err = -ENOMEM;
+ goto free_arrays;
+ }
+
+ for (i = 0; i < new_count; i++) {
+ new_tx[i] = apc->tx_qp[i];
+ new_rx[i] = apc->rxqs[i];
+ }
+ for (i = 0; i < tail_count; i++) {
+ tail_tx[i] = apc->tx_qp[new_count + i];
+ tail_rx[i] = apc->rxqs[new_count + i];
+ }
+
+ out_new->tx_qp = new_tx;
+ out_new->rxqs = new_rx;
+ out_new->indir_table = scratch->indir_table;
+ out_new->indir_table_sz = scratch->indir_table_sz;
+ out_new->rxobj_table = scratch->rxobj_table;
+ out_new->default_rxobj = apc->rxqs[0]->rxobj;
+ out_new->num_queues = new_count;
+ out_new->rx_queue_size = apc->rx_queue_size;
+ out_new->tx_queue_size = apc->tx_queue_size;
+ out_new->priv_flags = apc->priv_flags;
+ out_new->mtu = apc->configured_mtu;
+ out_new->bpf_prog = apc->bpf_prog;
+ out_new->rxfh_indir_lost = indir_lost;
+
+ scratch->indir_table = NULL;
+ scratch->rxobj_table = NULL;
+
+ memset(out_tail, 0, sizeof(*out_tail));
+ out_tail->tx_qp = tail_tx;
+ out_tail->rxqs = tail_rx;
+ out_tail->default_rxobj = INVALID_MANA_HANDLE;
+ out_tail->num_queues = tail_count;
+ out_tail->rx_queue_size = apc->rx_queue_size;
+ out_tail->tx_queue_size = apc->tx_queue_size;
+ out_tail->priv_flags = apc->priv_flags;
+ out_tail->mtu = apc->configured_mtu;
+ out_tail->bpf_prog = apc->bpf_prog;
+
+ return 0;
+
+free_arrays:
+ kfree(new_tx);
+ kfree(new_rx);
+ kfree(tail_tx);
+ kfree(tail_rx);
+ mana_cleanup_indir_table(scratch);
+ return err;
+}
+
+/* Free containers only; the live port still owns the queues. */
+void mana_discard_split(struct mana_qset *newq, struct mana_qset *tailq)
+{
+ kfree(newq->tx_qp);
+ kfree(newq->rxqs);
+ kfree(newq->indir_table);
+ kfree(newq->rxobj_table);
+ kfree(tailq->tx_qp);
+ kfree(tailq->rxqs);
+ memset(newq, 0, sizeof(*newq));
+ memset(tailq, 0, sizeof(*tailq));
+}
+
int mana_alloc_qset(struct mana_port_context *apc,
struct mana_port_context *scratch, unsigned int num_queues,
unsigned int rx_queue_size, unsigned int tx_queue_size,
@@ -4419,9 +4527,7 @@ int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq,
if (err)
goto rollback;
- /* Install XDP and per-RXQ references before steering reaches new
- * queues.
- */
+ /* Install XDP before steering reaches the incoming RXQs. */
mana_chn_setxdp(apc, mana_xdp_get(apc));
err = mana_config_rss(apc, TRI_STATE_TRUE, true, true);
diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
index a53e19b15bae..d3e465ea9428 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
@@ -737,6 +737,36 @@ static int mana_set_channels(struct net_device *ndev,
goto clear_flag;
}
+ if (new_count < apc->num_queues) {
+ struct mana_qset tailq;
+
+ err = mana_split_qset(apc, scratch, new_count, &newq, &tailq);
+ if (err)
+ goto free_scratch;
+
+ err = mana_publish_qset(apc, &newq, &oldq);
+ if (err) {
+ /* Discard containers only; their queues still belong to
+ * the old set.
+ */
+ mana_discard_split(&newq, &tailq);
+ goto free_scratch;
+ }
+
+ /* Wait for ndo_select_queue() readers of oldq.indir_table. Free
+ * only containers; the queues belong to the kept set or tail.
+ */
+ synchronize_net();
+
+ kfree(oldq.tx_qp);
+ kfree(oldq.rxqs);
+ kfree(oldq.indir_table);
+ kfree(oldq.rxobj_table);
+
+ mana_free_qset(scratch, &tailq);
+ goto free_scratch;
+ }
+
err = mana_alloc_qset(apc, scratch, new_count, apc->rx_queue_size,
apc->tx_queue_size, apc->priv_flags,
apc->configured_mtu, apc->bpf_prog, &newq);
diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index 9dad03150d1b..fef800bea2c0 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -735,6 +735,10 @@ int mana_alloc_qset(struct mana_port_context *apc,
unsigned int rx_queue_size, unsigned int tx_queue_size,
u32 priv_flags, int mtu, struct bpf_prog *bpf_prog,
struct mana_qset *out);
+int mana_split_qset(struct mana_port_context *apc,
+ struct mana_port_context *scratch, unsigned int new_count,
+ struct mana_qset *out_new, struct mana_qset *out_tail);
+void mana_discard_split(struct mana_qset *newq, struct mana_qset *tailq);
int mana_publish_qset(struct mana_port_context *apc, struct mana_qset *newq,
struct mana_qset *out_old);
void mana_publish_close_if_needed(struct mana_port_context *apc);
next prev parent reply other threads:[~2026-10-09 14:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-09 14:41 [PATCH net-next v6 00/13] net: mana: reconfigure by replacing the queue set Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 01/13] net: mana: add queue-set allocation and teardown helpers Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 02/13] net: mana: share the EQ pool across a queue-set swap Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 03/13] net: mana: keep per-queue statistics in the port context Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 04/13] net: mana: swap queue sets in mana_set_channels Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 05/13] net: mana: swap queue sets in mana_set_ringparam Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 06/13] net: mana: swap queue sets in mana_set_priv_flags Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 07/13] net: mana: swap queue sets in mana_change_mtu Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 08/13] net: mana: swap queue sets in mana_xdp_set Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 09/13] net: mana: do not bail out of mana_detach on dealloc failure Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 10/13] net: mana: release EQs left idle by a channel-count reduction Wei Hu
2026-10-09 14:41 ` [PATCH net-next v6 11/13] net: mana: keep a user-configured RSS table across a queue rebuild Wei Hu
2026-10-09 14:41 ` Wei Hu [this message]
2026-10-09 14:41 ` [PATCH net-next v6 13/13] net: mana: keep the existing queues when the channel count is raised Wei Hu
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