[PATCH net-next v2 13/15] ibmveth: Implement incremental MQ RX queue resize
From: Mingming Cao <hidden>
Date: 2026-07-01 22:26:50
Also in:
linuxppc-dev
Subsystem:
ibm power virtual ethernet device driver, linux for powerpc (32-bit and 64-bit), networking drivers, the rest · Maintainers:
Nick Child, Madhavan Srinivasan, Michael Ellerman, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Add ibmveth_resize_rx_queues_incremental() to grow or shrink adapter->num_rx_queues while the netdev stays up. Scale-up, per new queue index: alloc RX resources and per-queue pools register subordinate queue with PHYP request_irq(), then ibmveth_enable_irq(), then napi_enable update num_rx_queues, replenish new queues netif_set_real_num_rx_queues() Scale-down disables NAPI on excess queues, drains pending buffers, disables PHYP IRQ delivery and waits for in-flight handlers with synchronize_irq() before lowering num_rx_queues, then tears down IRQ/PHYP/memory. Reject out-of-range new_count. On scale-down netif failure, re-enable NAPI on queues not yet torn down. Refresh VIO CMO entitlement after a successful resize when FW_FEATURE_CMO is enabled. Scale-up rollback mirrors scale-down: drain posted buffers and wait for in-flight handlers before deregistering with PHYP. In replenish_task(), skip queues with queue_index >= num_rx_queues and require pool->free_map before replenishing so in-flight handlers avoid queues being torn down without clearing probe-time pool->active on free. Queue 0 is never removed here. Scale-up failure unwinds only queues added in this call. ethtool -L wiring is next. Signed-off-by: Mingming Cao <redacted> Reviewed-by: Dave Marquardt <redacted> --- drivers/net/ethernet/ibm/ibmveth.c | 183 ++++++++++++++++++++++++++++- 1 file changed, 178 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index cd0acd1715da..ac4d89a66a8d 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c@@ -945,18 +945,22 @@ static void ibmveth_replenish_task(struct ibmveth_adapter *adapter, unsigned long flags; int i; - if (queue_index >= adapter->num_rx_queues) - return; - adapter->replenish_task_cycles++; + if (queue_index >= adapter->num_rx_queues) { + netdev_dbg(adapter->netdev, + "Skipping replenish for freed queue %d (num_queues=%d)\n", + queue_index, adapter->num_rx_queues); + return; + } + spin_lock_irqsave(&rxq->replenish_lock, flags); for (i = (IBMVETH_NUM_BUFF_POOLS - 1); i >= 0; i--) { struct ibmveth_buff_pool *pool = &adapter->rx_buff_pool[queue_index][i]; - if (pool->active && + if (pool->active && pool->free_map && (atomic_read(&pool->available) < pool->threshold)) ibmveth_replenish_buffer_pool(adapter, pool, queue_index);
@@ -1682,7 +1686,7 @@ ibmveth_register_single_rx_queue(struct ibmveth_adapter *adapter, * the IRQ mapping for subordinate queues. Queue 0 is freed only through * ibmveth_free_all_queues() (H_FREE_LOGICAL_LAN). */ -static void __maybe_unused +static void ibmveth_deregister_single_rx_queue(struct ibmveth_adapter *adapter, int queue_idx) {
@@ -1714,6 +1718,175 @@ ibmveth_deregister_single_rx_queue(struct ibmveth_adapter *adapter, netdev_dbg(adapter->netdev, "Deregistered queue %d\n", queue_idx); } +/** + * ibmveth_resize_rx_queues_incremental - Resize RX queue count incrementally + * @adapter: ibmveth adapter structure + * @new_count: Target number of RX queues + * @rxq_entries: Number of entries per RX queue + * + * Adds or removes RX queues without tearing down the entire adapter. + * Active queues continue receiving during scale-up; scale-down drains + * excess queues before deregistering them with the hypervisor. + * + * Return: 0 on success, negative error code on failure + */ +static int +ibmveth_resize_rx_queues_incremental(struct ibmveth_adapter *adapter, + int new_count, int rxq_entries) +{ + struct net_device *netdev = adapter->netdev; + u64 mac_address = ether_addr_to_u64(netdev->dev_addr); + int old_count = adapter->num_rx_queues; + int failed_queue; + int rc, i; + + if (old_count == new_count) { + netdev_dbg(netdev, "RX queue count unchanged (%d), nothing to do\n", + old_count); + return 0; + } + + if (new_count < 1 || new_count > IBMVETH_MAX_RX_QUEUES) { + netdev_err(netdev, "Invalid RX queue count %d (must be 1-%d)\n", + new_count, IBMVETH_MAX_RX_QUEUES); + return -EINVAL; + } + + netdev_info(netdev, "Incrementally resizing RX queues: %d to %d\n", + old_count, new_count); + + if (new_count > old_count) { + netdev_dbg(netdev, "Scale-up: adding queues %d-%d\n", + old_count, new_count - 1); + + for (i = old_count; i < new_count; i++) { + rc = ibmveth_alloc_single_rx_queue(adapter, i, rxq_entries); + if (rc) { + netdev_err(netdev, "Failed to allocate queue %d: %d\n", + i, rc); + goto cleanup_new_queues; + } + + rc = ibmveth_register_single_rx_queue(adapter, i, + mac_address); + if (rc) { + netdev_err(netdev, "Failed to register queue %d: %d\n", + i, rc); + ibmveth_free_single_rx_queue(adapter, i); + goto cleanup_new_queues; + } + + rc = ibmveth_setup_single_rx_interrupt(adapter, i); + if (rc) { + netdev_err(netdev, + "Failed to setup IRQ for queue %d: %d\n", + i, rc); + ibmveth_deregister_single_rx_queue(adapter, i); + ibmveth_free_single_rx_queue(adapter, i); + goto cleanup_new_queues; + } + + rc = ibmveth_enable_irq(adapter, i); + if (rc) { + netdev_err(netdev, + "Failed to enable IRQ for queue %d: %d\n", + i, rc); + ibmveth_cleanup_single_rx_interrupt(adapter, i); + ibmveth_deregister_single_rx_queue(adapter, i); + ibmveth_free_single_rx_queue(adapter, i); + goto cleanup_new_queues; + } + + napi_enable(&adapter->napi[i]); + } + + adapter->num_rx_queues = new_count; + + for (i = old_count; i < new_count; i++) + ibmveth_replenish_task(adapter, i); + + rc = netif_set_real_num_rx_queues(netdev, new_count); + if (rc) { + netdev_err(netdev, "Failed to set real RX queues to %d: %d\n", + new_count, rc); + goto cleanup_new_queues; + } + } else { + netdev_dbg(netdev, "Scale-down: removing queues %d-%d\n", + new_count, old_count - 1); + + for (i = new_count; i < old_count; i++) + napi_disable(&adapter->napi[i]); + + for (i = new_count; i < old_count; i++) + ibmveth_drain_rx_queue(adapter, i); + + synchronize_net(); + + rc = netif_set_real_num_rx_queues(netdev, new_count); + if (rc) { + netdev_err(netdev, "Failed to set real RX queues to %d: %d\n", + new_count, rc); + for (i = new_count; i < old_count; i++) + napi_enable(&adapter->napi[i]); + return rc; + } + + /* Disable hypervisor interrupts and wait for handlers to complete + * before updating num_rx_queues. + */ + for (i = new_count; i < old_count; i++) { + ibmveth_disable_irq(adapter, i); + synchronize_irq(adapter->queue_irq[i]); + } + + adapter->num_rx_queues = new_count; + + for (i = new_count; i < old_count; i++) { + ibmveth_cleanup_single_rx_interrupt(adapter, i); + ibmveth_deregister_single_rx_queue(adapter, i); + ibmveth_free_single_rx_queue(adapter, i); + } + } + + netdev_info(netdev, "Successfully resized to %d RX queues (incremental)\n", + adapter->num_rx_queues); + + if (firmware_has_feature(FW_FEATURE_CMO)) + vio_cmo_set_dev_desired(adapter->vdev, + ibmveth_get_desired_dma(adapter->vdev)); + + return 0; + +cleanup_new_queues: + failed_queue = i; + netdev_err(netdev, + "Scale-up failed at queue %d, cleaning up queues %d-%d\n", + failed_queue, old_count, failed_queue - 1); + for (i = old_count; i < failed_queue; i++) + napi_disable(&adapter->napi[i]); + + for (i = old_count; i < failed_queue; i++) + ibmveth_drain_rx_queue(adapter, i); + + synchronize_net(); + + for (i = old_count; i < failed_queue; i++) { + ibmveth_disable_irq(adapter, i); + synchronize_irq(adapter->queue_irq[i]); + } + + for (i = old_count; i < failed_queue; i++) { + ibmveth_cleanup_single_rx_interrupt(adapter, i); + ibmveth_deregister_single_rx_queue(adapter, i); + ibmveth_free_single_rx_queue(adapter, i); + } + adapter->num_rx_queues = old_count; + netdev_warn(netdev, "Keeping %d queues after scale-up failure\n", + old_count); + return rc; +} + /** * ibmveth_free_all_queues - Free all RX queues at once * @adapter: ibmveth adapter structure
--
2.39.3 (Apple Git-146)