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ibmvnic: Assign IRQ affinity hints to device queues
Assign affinity hints to ibmvnic device queue interrupts. Affinity hints are assigned and removed during sub-crq init and teardown, respectively. This update should improve latency if utilized as interrupt lines and processing are more equally distributed among CPU's. This implementation is based on the virtio_net driver. Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com> Signed-off-by: Dany Madden <drt@linux.ibm.com> Signed-off-by: Nick Child <nnac123@linux.ibm.com> Reviewed-by: Rick Lindsley <ricklind@linux.ibm.com> Reviewed-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nick Child
David S. Miller
parent
e384cf35bf
commit
44fbc1b6e0
@ -68,6 +68,7 @@
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#include <linux/workqueue.h>
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#include <linux/if_vlan.h>
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#include <linux/utsname.h>
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#include <linux/cpu.h>
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#include "ibmvnic.h"
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@ -171,6 +172,132 @@ static int send_version_xchg(struct ibmvnic_adapter *adapter)
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return ibmvnic_send_crq(adapter, &crq);
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}
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static void ibmvnic_clean_queue_affinity(struct ibmvnic_adapter *adapter,
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struct ibmvnic_sub_crq_queue *queue)
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{
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if (!(queue && queue->irq))
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return;
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cpumask_clear(queue->affinity_mask);
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if (irq_set_affinity_and_hint(queue->irq, NULL))
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netdev_warn(adapter->netdev,
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"%s: Clear affinity failed, queue addr = %p, IRQ = %d\n",
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__func__, queue, queue->irq);
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}
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static void ibmvnic_clean_affinity(struct ibmvnic_adapter *adapter)
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{
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struct ibmvnic_sub_crq_queue **rxqs;
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struct ibmvnic_sub_crq_queue **txqs;
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int num_rxqs, num_txqs;
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int rc, i;
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rc = 0;
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rxqs = adapter->rx_scrq;
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txqs = adapter->tx_scrq;
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num_txqs = adapter->num_active_tx_scrqs;
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num_rxqs = adapter->num_active_rx_scrqs;
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netdev_dbg(adapter->netdev, "%s: Cleaning irq affinity hints", __func__);
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if (txqs) {
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for (i = 0; i < num_txqs; i++)
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ibmvnic_clean_queue_affinity(adapter, txqs[i]);
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}
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if (rxqs) {
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for (i = 0; i < num_rxqs; i++)
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ibmvnic_clean_queue_affinity(adapter, rxqs[i]);
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}
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}
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static int ibmvnic_set_queue_affinity(struct ibmvnic_sub_crq_queue *queue,
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unsigned int *cpu, int *stragglers,
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int stride)
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{
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cpumask_var_t mask;
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int i;
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int rc = 0;
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if (!(queue && queue->irq))
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return rc;
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/* cpumask_var_t is either a pointer or array, allocation works here */
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if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
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return -ENOMEM;
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/* while we have extra cpu give one extra to this irq */
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if (*stragglers) {
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stride++;
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(*stragglers)--;
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}
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/* atomic write is safer than writing bit by bit directly */
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for (i = 0; i < stride; i++) {
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cpumask_set_cpu(*cpu, mask);
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*cpu = cpumask_next_wrap(*cpu, cpu_online_mask,
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nr_cpu_ids, false);
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}
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/* set queue affinity mask */
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cpumask_copy(queue->affinity_mask, mask);
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rc = irq_set_affinity_and_hint(queue->irq, queue->affinity_mask);
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free_cpumask_var(mask);
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return rc;
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}
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/* assumes cpu read lock is held */
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static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter)
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{
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struct ibmvnic_sub_crq_queue **rxqs = adapter->rx_scrq;
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struct ibmvnic_sub_crq_queue **txqs = adapter->tx_scrq;
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struct ibmvnic_sub_crq_queue *queue;
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int num_rxqs = adapter->num_active_rx_scrqs;
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int num_txqs = adapter->num_active_tx_scrqs;
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int total_queues, stride, stragglers, i;
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unsigned int num_cpu, cpu;
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int rc = 0;
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netdev_dbg(adapter->netdev, "%s: Setting irq affinity hints", __func__);
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if (!(adapter->rx_scrq && adapter->tx_scrq)) {
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netdev_warn(adapter->netdev,
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"%s: Set affinity failed, queues not allocated\n",
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__func__);
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return;
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}
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total_queues = num_rxqs + num_txqs;
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num_cpu = num_online_cpus();
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/* number of cpu's assigned per irq */
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stride = max_t(int, num_cpu / total_queues, 1);
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/* number of leftover cpu's */
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stragglers = num_cpu >= total_queues ? num_cpu % total_queues : 0;
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/* next available cpu to assign irq to */
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cpu = cpumask_next(-1, cpu_online_mask);
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for (i = 0; i < num_txqs; i++) {
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queue = txqs[i];
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rc = ibmvnic_set_queue_affinity(queue, &cpu, &stragglers,
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stride);
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if (rc)
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goto out;
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}
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for (i = 0; i < num_rxqs; i++) {
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queue = rxqs[i];
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rc = ibmvnic_set_queue_affinity(queue, &cpu, &stragglers,
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stride);
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if (rc)
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goto out;
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}
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out:
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if (rc) {
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netdev_warn(adapter->netdev,
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"%s: Set affinity failed, queue addr = %p, IRQ = %d, rc = %d.\n",
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__func__, queue, queue->irq, rc);
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ibmvnic_clean_affinity(adapter);
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}
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}
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static long h_reg_sub_crq(unsigned long unit_address, unsigned long token,
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unsigned long length, unsigned long *number,
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unsigned long *irq)
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@ -3626,6 +3753,8 @@ static int reset_sub_crq_queues(struct ibmvnic_adapter *adapter)
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if (!adapter->tx_scrq || !adapter->rx_scrq)
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return -EINVAL;
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ibmvnic_clean_affinity(adapter);
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for (i = 0; i < adapter->req_tx_queues; i++) {
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netdev_dbg(adapter->netdev, "Re-setting tx_scrq[%d]\n", i);
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rc = reset_one_sub_crq_queue(adapter, adapter->tx_scrq[i]);
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@ -3675,6 +3804,7 @@ static void release_sub_crq_queue(struct ibmvnic_adapter *adapter,
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dma_unmap_single(dev, scrq->msg_token, 4 * PAGE_SIZE,
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DMA_BIDIRECTIONAL);
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free_pages((unsigned long)scrq->msgs, 2);
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free_cpumask_var(scrq->affinity_mask);
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kfree(scrq);
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}
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@ -3695,6 +3825,8 @@ static struct ibmvnic_sub_crq_queue *init_sub_crq_queue(struct ibmvnic_adapter
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dev_warn(dev, "Couldn't allocate crq queue messages page\n");
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goto zero_page_failed;
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}
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if (!zalloc_cpumask_var(&scrq->affinity_mask, GFP_KERNEL))
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goto cpumask_alloc_failed;
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scrq->msg_token = dma_map_single(dev, scrq->msgs, 4 * PAGE_SIZE,
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DMA_BIDIRECTIONAL);
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@ -3747,6 +3879,8 @@ reg_failed:
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dma_unmap_single(dev, scrq->msg_token, 4 * PAGE_SIZE,
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DMA_BIDIRECTIONAL);
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map_failed:
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free_cpumask_var(scrq->affinity_mask);
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cpumask_alloc_failed:
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free_pages((unsigned long)scrq->msgs, 2);
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zero_page_failed:
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kfree(scrq);
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@ -3758,6 +3892,7 @@ static void release_sub_crqs(struct ibmvnic_adapter *adapter, bool do_h_free)
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{
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int i;
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ibmvnic_clean_affinity(adapter);
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if (adapter->tx_scrq) {
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for (i = 0; i < adapter->num_active_tx_scrqs; i++) {
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if (!adapter->tx_scrq[i])
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@ -4035,6 +4170,11 @@ static int init_sub_crq_irqs(struct ibmvnic_adapter *adapter)
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goto req_rx_irq_failed;
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}
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}
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cpus_read_lock();
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ibmvnic_set_affinity(adapter);
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cpus_read_unlock();
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return rc;
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req_rx_irq_failed:
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@ -825,6 +825,7 @@ struct ibmvnic_sub_crq_queue {
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atomic_t used;
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char name[32];
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u64 handle;
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cpumask_var_t affinity_mask;
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} ____cacheline_aligned;
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struct ibmvnic_long_term_buff {
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