[PATCH net-next v4 04/14] ibmveth: Refactor buffer pool management for per-queue MQ RX
From: Mingming Cao <hidden>
Date: 2026-07-31 00:48:21
Also in:
netdev
Subsystem:
ibm power virtual ethernet device driver, linux for powerpc (32-bit and 64-bit), networking drivers, the rest · Maintainers:
Nick Child, Madhavan Srinivasan, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Legacy ibmveth uses five adapter-level RX buffer pools (512 B through
64 KiB). pool_active[] enables the standard-MTU pools by default;
larger pools activate when MTU requires them. With single-queue RX
that set is shared on one completion path.
MQ requires the same pool model per queue: buffers post with
H_ADD_LOGICAL_LAN_BUFFERS_QUEUE against a queue handle and completions
return on that queue. Sharing pools across queues would mix ownership
and break queue-local replenish/drain/teardown.
Refactor around queue-local pools:
rx_buff_pool[queue][pool]
ibmveth_alloc_queue_buffer_pools()
ibmveth_free_queue_buffer_pools()
ibmveth_alloc_buffer_pools() / ibmveth_free_buffer_pools()
Queue 0 remains the template for pool geometry (size, buff_size,
threshold, index, active). For queues 1..N we copy metadata from
queue 0, then allocate backing arrays/skbs per queue.
Wire the helpers into open()/close() in the same patch. Runtime
remains single-queue (num_rx_queues is still 1).
Error handling is queue-safe:
- allocation failure unwinds only what that queue allocated, then
prior queues in the caller
- free paths release by real allocations (free_map/dma_addr/skbuff),
not only pool->active
That allocation-based free check is intentional: later resize and
failure paths can leave memory allocated after active was cleared.
Also disable the 64 KiB pool by default at standard MTU. MTU changes
activate it when required; leaving it enabled would pin about 16 MiB
per RX queue in MQ mode.
Signed-off-by: Mingming Cao <redacted>
Reviewed-by: Dave Marquardt <redacted>
Tested-by: Shaik Abdulla <redacted>
---
Changes in v4:
- Introduce the pool helpers in the same patch that wires their first
open/close callers, instead of leaving unused statics.
- Copy pool->index when cloning queue-0 geometry to later queues
(needed for correlators; also required by incremental resize).
drivers/net/ethernet/ibm/ibmveth.c | 164 +++++++++++++++++++++++++----
drivers/net/ethernet/ibm/ibmveth.h | 2 +-
2 files changed, 145 insertions(+), 21 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 1007dd95cde0..7a2ed49cad4f 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c@@ -625,6 +625,145 @@ static void ibmveth_free_buffer_pool(struct ibmveth_adapter *adapter, } } +/** + * ibmveth_alloc_queue_buffer_pools - Allocate buffer pools for a single queue + * @adapter: ibmveth adapter structure + * @queue: queue index + * + * Allocates all active buffer pools for the specified queue. + * Pool metadata must be initialized before calling this function. + * + * Return: 0 on success, negative error code on failure + */ +static int ibmveth_alloc_queue_buffer_pools(struct ibmveth_adapter *adapter, + int queue) +{ + struct net_device *netdev = adapter->netdev; + int i; + + for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++) { + struct ibmveth_buff_pool *bpool = + &adapter->rx_buff_pool[queue][i]; + + if (!bpool->active) + continue; + + if (ibmveth_alloc_buffer_pool(bpool)) { + netdev_err(netdev, + "pool %d/%d alloc failed (size=%u count=%u)\n", + i, queue, + bpool->buff_size, + bpool->size); + bpool->active = 0; + + /* Free pools allocated so far for this queue */ + while (--i >= 0) { + struct ibmveth_buff_pool *fpool = + &adapter->rx_buff_pool[queue][i]; + + if (fpool->active) + ibmveth_free_buffer_pool(adapter, + fpool); + } + return -ENOMEM; + } + } + + return 0; +} + +/** + * ibmveth_free_queue_buffer_pools - Free buffer pools for a single queue + * @adapter: ibmveth adapter structure + * @queue: queue index + * + * Frees all active buffer pools for the specified queue. + */ +static void ibmveth_free_queue_buffer_pools(struct ibmveth_adapter *adapter, + int queue) +{ + int i; + + for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++) { + struct ibmveth_buff_pool *pool = + &adapter->rx_buff_pool[queue][i]; + + /* Free pool if it has allocated memory, regardless of + * active flag. Pools may have memory allocated but not + * marked active during queue scale-up, so we must check + * for actual allocations. + */ + if (pool->free_map || pool->dma_addr || pool->skbuff) + ibmveth_free_buffer_pool(adapter, pool); + } +} + +/** + * ibmveth_alloc_buffer_pools - Allocate buffer pools for all queues + * @adapter: ibmveth adapter structure + * + * Initializes pool metadata for queues 1-N from queue 0 settings, + * then allocates buffer pools for all queues using the helper function. + * + * Return: 0 on success, negative error code on failure + */ +static int +ibmveth_alloc_buffer_pools(struct ibmveth_adapter *adapter) +{ + struct net_device *netdev = adapter->netdev; + int i, q, rc; + + /* Initialize pool metadata for queues 1-15 from queue 0 settings */ + for (q = 1; q < adapter->num_rx_queues; q++) { + for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++) { + struct ibmveth_buff_pool *src = + &adapter->rx_buff_pool[0][i]; + struct ibmveth_buff_pool *dst = + &adapter->rx_buff_pool[q][i]; + + dst->size = src->size; + dst->index = src->index; + dst->buff_size = src->buff_size; + dst->threshold = src->threshold; + dst->active = src->active; + } + } + + /* Allocate actual buffers for all queues */ + for (q = 0; q < adapter->num_rx_queues; q++) { + rc = ibmveth_alloc_queue_buffer_pools(adapter, q); + if (rc) { + /* Free pools for all previous queues */ + while (--q >= 0) + ibmveth_free_queue_buffer_pools(adapter, q); + return rc; + } + } + + netdev_dbg(netdev, "allocated buffer pools for %d queue(s)\n", + adapter->num_rx_queues); + return 0; +} + +/** + * ibmveth_free_buffer_pools - Free buffer pools for all queues + * @adapter: ibmveth adapter structure + * + * Frees buffer pools for all queues using the helper function. + */ +static void +ibmveth_free_buffer_pools(struct ibmveth_adapter *adapter) +{ + int q; + + /* Free buffer pools for all queues */ + for (q = 0; q < adapter->num_rx_queues; q++) + ibmveth_free_queue_buffer_pools(adapter, q); + + netdev_dbg(adapter->netdev, "freed buffer pools for %d queue(s)\n", + adapter->num_rx_queues); +} + /** * ibmveth_remove_buffer_from_pool - remove a buffer from a pool * @adapter: adapter instance
@@ -850,16 +989,9 @@ static int ibmveth_open(struct net_device *netdev) goto out_free_tx_ltb; } - for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++) { - if (!adapter->rx_buff_pool[0][i].active) - continue; - if (ibmveth_alloc_buffer_pool(&adapter->rx_buff_pool[0][i])) { - netdev_err(netdev, "unable to alloc pool\n"); - adapter->rx_buff_pool[0][i].active = 0; - rc = -ENOMEM; - goto out_free_buffer_pools; - } - } + rc = ibmveth_alloc_buffer_pools(adapter); + if (rc) + goto out_free_tx_ltb; netdev_dbg(netdev, "registering irq 0x%x\n", netdev->irq); rc = request_irq(netdev->irq, ibmveth_interrupt, 0, netdev->name,
@@ -884,11 +1016,7 @@ static int ibmveth_open(struct net_device *netdev) return 0; out_free_buffer_pools: - while (--i >= 0) { - if (adapter->rx_buff_pool[0][i].active) - ibmveth_free_buffer_pool(adapter, - &adapter->rx_buff_pool[0][i]); - } + ibmveth_free_buffer_pools(adapter); out_free_tx_ltb: while (--i >= 0) ibmveth_free_tx_ltb(adapter, i);
@@ -927,14 +1055,10 @@ static int ibmveth_close(struct net_device *netdev) ibmveth_update_rx_no_buffer(adapter); + ibmveth_free_buffer_pools(adapter); ibmveth_cleanup_rx_resources(adapter); ibmveth_free_filter_list(adapter); - for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++) - if (adapter->rx_buff_pool[0][i].active) - ibmveth_free_buffer_pool(adapter, - &adapter->rx_buff_pool[0][i]); - for (i = 0; i < netdev->real_num_tx_queues; i++) ibmveth_free_tx_ltb(adapter, i);
diff --git a/drivers/net/ethernet/ibm/ibmveth.h b/drivers/net/ethernet/ibm/ibmveth.h
index 8eaa3942fc40..abcd4054c67e 100644
--- a/drivers/net/ethernet/ibm/ibmveth.h
+++ b/drivers/net/ethernet/ibm/ibmveth.h@@ -265,7 +265,7 @@ static inline long h_illan_attributes(unsigned long unit_address, static int pool_size[] = { 512, 1024 * 2, 1024 * 16, 1024 * 32, 1024 * 64 }; static int pool_count[] = { 256, 512, 256, 256, 256 }; static int pool_count_cmo[] = { 256, 512, 256, 256, 64 }; -static int pool_active[] = { 1, 1, 0, 0, 1}; +static int pool_active[] = { 1, 1, 0, 0, 0}; #define IBM_VETH_INVALID_MAP ((u16)0xffff)
--
2.50.1 (Apple Git-155)