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enic: add low latency socket busy_poll support
This patch adds support for low latency busy_poll. * Introduce drivers ndo_busy_poll function enic_busy_poll, which is called by socket waiting for data. * Introduce locking between napi_poll nad busy_poll * enic_busy_poll cleans up all the rx pkts possible. While in busy_poll, rq holds the state ENIC_POLL_STATE_POLL. While in napi_poll, rq holds the state ENIC_POLL_STATE_NAPI. * in napi_poll we return if we are in busy_poll. Incase of INTx & msix, we just service wq and return if busy_poll is going on. Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Govindarajulu Varadarajan
David S. Miller
parent
8e091340cf
commit
14747cd977
@ -42,6 +42,9 @@
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#ifdef CONFIG_RFS_ACCEL
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#include <linux/cpu_rmap.h>
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#endif
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#ifdef CONFIG_NET_RX_BUSY_POLL
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#include <net/busy_poll.h>
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#endif
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#include "cq_enet_desc.h"
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#include "vnic_dev.h"
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@ -1053,10 +1056,12 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq,
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if (vlan_stripped)
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__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tci);
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if (netdev->features & NETIF_F_GRO)
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napi_gro_receive(&enic->napi[q_number], skb);
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else
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skb_mark_napi_id(skb, &enic->napi[rq->index]);
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if (enic_poll_busy_polling(rq) ||
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!(netdev->features & NETIF_F_GRO))
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netif_receive_skb(skb);
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else
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napi_gro_receive(&enic->napi[q_number], skb);
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if (enic->rx_coalesce_setting.use_adaptive_rx_coalesce)
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enic_intr_update_pkt_size(&cq->pkt_size_counter,
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bytes_written);
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@ -1093,16 +1098,22 @@ static int enic_poll(struct napi_struct *napi, int budget)
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unsigned int work_done, rq_work_done = 0, wq_work_done;
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int err;
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/* Service RQ (first) and WQ
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*/
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wq_work_done = vnic_cq_service(&enic->cq[cq_wq], wq_work_to_do,
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enic_wq_service, NULL);
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if (!enic_poll_lock_napi(&enic->rq[cq_rq])) {
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if (wq_work_done > 0)
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vnic_intr_return_credits(&enic->intr[intr],
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wq_work_done,
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0 /* dont unmask intr */,
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0 /* dont reset intr timer */);
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return rq_work_done;
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}
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if (budget > 0)
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rq_work_done = vnic_cq_service(&enic->cq[cq_rq],
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rq_work_to_do, enic_rq_service, NULL);
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wq_work_done = vnic_cq_service(&enic->cq[cq_wq],
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wq_work_to_do, enic_wq_service, NULL);
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/* Accumulate intr event credits for this polling
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* cycle. An intr event is the completion of a
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* a WQ or RQ packet.
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@ -1134,6 +1145,7 @@ static int enic_poll(struct napi_struct *napi, int budget)
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napi_complete(napi);
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vnic_intr_unmask(&enic->intr[intr]);
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}
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enic_poll_unlock_napi(&enic->rq[cq_rq]);
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return rq_work_done;
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}
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@ -1234,6 +1246,34 @@ static void enic_set_rx_cpu_rmap(struct enic *enic)
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#endif /* CONFIG_RFS_ACCEL */
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#ifdef CONFIG_NET_RX_BUSY_POLL
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int enic_busy_poll(struct napi_struct *napi)
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{
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struct net_device *netdev = napi->dev;
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struct enic *enic = netdev_priv(netdev);
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unsigned int rq = (napi - &enic->napi[0]);
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unsigned int cq = enic_cq_rq(enic, rq);
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unsigned int intr = enic_msix_rq_intr(enic, rq);
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unsigned int work_to_do = -1; /* clean all pkts possible */
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unsigned int work_done;
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if (!enic_poll_lock_poll(&enic->rq[rq]))
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return LL_FLUSH_BUSY;
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work_done = vnic_cq_service(&enic->cq[cq], work_to_do,
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enic_rq_service, NULL);
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if (work_done > 0)
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vnic_intr_return_credits(&enic->intr[intr],
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work_done, 0, 0);
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vnic_rq_fill(&enic->rq[rq], enic_rq_alloc_buf);
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if (enic->rx_coalesce_setting.use_adaptive_rx_coalesce)
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enic_calc_int_moderation(enic, &enic->rq[rq]);
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enic_poll_unlock_poll(&enic->rq[rq]);
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return work_done;
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}
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#endif /* CONFIG_NET_RX_BUSY_POLL */
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static int enic_poll_msix(struct napi_struct *napi, int budget)
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{
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struct net_device *netdev = napi->dev;
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@ -1245,6 +1285,8 @@ static int enic_poll_msix(struct napi_struct *napi, int budget)
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unsigned int work_done = 0;
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int err;
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if (!enic_poll_lock_napi(&enic->rq[rq]))
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return work_done;
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/* Service RQ
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*/
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@ -1290,6 +1332,7 @@ static int enic_poll_msix(struct napi_struct *napi, int budget)
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enic_set_int_moderation(enic, &enic->rq[rq]);
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vnic_intr_unmask(&enic->intr[intr]);
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}
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enic_poll_unlock_napi(&enic->rq[rq]);
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return work_done;
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}
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@ -1538,8 +1581,10 @@ static int enic_open(struct net_device *netdev)
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netif_tx_wake_all_queues(netdev);
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for (i = 0; i < enic->rq_count; i++)
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for (i = 0; i < enic->rq_count; i++) {
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enic_busy_poll_init_lock(&enic->rq[i]);
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napi_enable(&enic->napi[i]);
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}
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enic_dev_enable(enic);
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@ -1578,8 +1623,13 @@ static int enic_stop(struct net_device *netdev)
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enic_dev_disable(enic);
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for (i = 0; i < enic->rq_count; i++)
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local_bh_disable();
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for (i = 0; i < enic->rq_count; i++) {
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napi_disable(&enic->napi[i]);
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while (!enic_poll_lock_napi(&enic->rq[i]))
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mdelay(1);
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}
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local_bh_enable();
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netif_carrier_off(netdev);
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netif_tx_disable(netdev);
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@ -2070,6 +2120,9 @@ static const struct net_device_ops enic_netdev_dynamic_ops = {
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#ifdef CONFIG_RFS_ACCEL
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.ndo_rx_flow_steer = enic_rx_flow_steer,
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#endif
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#ifdef CONFIG_NET_RX_BUSY_POLL
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.ndo_busy_poll = enic_busy_poll,
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#endif
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};
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static const struct net_device_ops enic_netdev_ops = {
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@ -2093,14 +2146,19 @@ static const struct net_device_ops enic_netdev_ops = {
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#ifdef CONFIG_RFS_ACCEL
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.ndo_rx_flow_steer = enic_rx_flow_steer,
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#endif
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#ifdef CONFIG_NET_RX_BUSY_POLL
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.ndo_busy_poll = enic_busy_poll,
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#endif
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};
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static void enic_dev_deinit(struct enic *enic)
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{
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unsigned int i;
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for (i = 0; i < enic->rq_count; i++)
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for (i = 0; i < enic->rq_count; i++) {
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napi_hash_del(&enic->napi[i]);
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netif_napi_del(&enic->napi[i]);
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}
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enic_free_vnic_resources(enic);
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enic_clear_intr_mode(enic);
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@ -2166,11 +2224,14 @@ static int enic_dev_init(struct enic *enic)
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switch (vnic_dev_get_intr_mode(enic->vdev)) {
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default:
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netif_napi_add(netdev, &enic->napi[0], enic_poll, 64);
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napi_hash_add(&enic->napi[0]);
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break;
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case VNIC_DEV_INTR_MODE_MSIX:
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for (i = 0; i < enic->rq_count; i++)
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for (i = 0; i < enic->rq_count; i++) {
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netif_napi_add(netdev, &enic->napi[i],
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enic_poll_msix, 64);
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napi_hash_add(&enic->napi[i]);
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}
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break;
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}
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@ -85,6 +85,21 @@ struct vnic_rq {
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struct vnic_rq_buf *to_clean;
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void *os_buf_head;
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unsigned int pkts_outstanding;
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#ifdef CONFIG_NET_RX_BUSY_POLL
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#define ENIC_POLL_STATE_IDLE 0
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#define ENIC_POLL_STATE_NAPI (1 << 0) /* NAPI owns this poll */
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#define ENIC_POLL_STATE_POLL (1 << 1) /* poll owns this poll */
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#define ENIC_POLL_STATE_NAPI_YIELD (1 << 2) /* NAPI yielded this poll */
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#define ENIC_POLL_STATE_POLL_YIELD (1 << 3) /* poll yielded this poll */
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#define ENIC_POLL_YIELD (ENIC_POLL_STATE_NAPI_YIELD | \
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ENIC_POLL_STATE_POLL_YIELD)
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#define ENIC_POLL_LOCKED (ENIC_POLL_STATE_NAPI | \
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ENIC_POLL_STATE_POLL)
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#define ENIC_POLL_USER_PEND (ENIC_POLL_STATE_POLL | \
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ENIC_POLL_STATE_POLL_YIELD)
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unsigned int bpoll_state;
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spinlock_t bpoll_lock;
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#endif /* CONFIG_NET_RX_BUSY_POLL */
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};
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static inline unsigned int vnic_rq_desc_avail(struct vnic_rq *rq)
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@ -197,6 +212,113 @@ static inline int vnic_rq_fill(struct vnic_rq *rq,
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return 0;
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}
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#ifdef CONFIG_NET_RX_BUSY_POLL
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static inline void enic_busy_poll_init_lock(struct vnic_rq *rq)
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{
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spin_lock_init(&rq->bpoll_lock);
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rq->bpoll_state = ENIC_POLL_STATE_IDLE;
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}
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static inline bool enic_poll_lock_napi(struct vnic_rq *rq)
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{
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bool rc = true;
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spin_lock(&rq->bpoll_lock);
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if (rq->bpoll_state & ENIC_POLL_LOCKED) {
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WARN_ON(rq->bpoll_state & ENIC_POLL_STATE_NAPI);
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rq->bpoll_state |= ENIC_POLL_STATE_NAPI_YIELD;
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rc = false;
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} else {
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rq->bpoll_state = ENIC_POLL_STATE_NAPI;
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}
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spin_unlock(&rq->bpoll_lock);
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return rc;
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}
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static inline bool enic_poll_unlock_napi(struct vnic_rq *rq)
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{
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bool rc = false;
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spin_lock(&rq->bpoll_lock);
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WARN_ON(rq->bpoll_state &
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(ENIC_POLL_STATE_POLL | ENIC_POLL_STATE_NAPI_YIELD));
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if (rq->bpoll_state & ENIC_POLL_STATE_POLL_YIELD)
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rc = true;
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rq->bpoll_state = ENIC_POLL_STATE_IDLE;
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spin_unlock(&rq->bpoll_lock);
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return rc;
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}
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static inline bool enic_poll_lock_poll(struct vnic_rq *rq)
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{
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bool rc = true;
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spin_lock_bh(&rq->bpoll_lock);
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if (rq->bpoll_state & ENIC_POLL_LOCKED) {
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rq->bpoll_state |= ENIC_POLL_STATE_POLL_YIELD;
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rc = false;
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} else {
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rq->bpoll_state |= ENIC_POLL_STATE_POLL;
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}
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spin_unlock_bh(&rq->bpoll_lock);
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return rc;
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}
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static inline bool enic_poll_unlock_poll(struct vnic_rq *rq)
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{
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bool rc = false;
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spin_lock_bh(&rq->bpoll_lock);
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WARN_ON(rq->bpoll_state & ENIC_POLL_STATE_NAPI);
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if (rq->bpoll_state & ENIC_POLL_STATE_POLL_YIELD)
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rc = true;
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rq->bpoll_state = ENIC_POLL_STATE_IDLE;
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spin_unlock_bh(&rq->bpoll_lock);
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return rc;
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}
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static inline bool enic_poll_busy_polling(struct vnic_rq *rq)
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{
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WARN_ON(!(rq->bpoll_state & ENIC_POLL_LOCKED));
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return rq->bpoll_state & ENIC_POLL_USER_PEND;
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}
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#else
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static inline void enic_busy_poll_init_lock(struct vnic_rq *rq)
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{
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}
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static inline bool enic_poll_lock_napi(struct vnic_rq *rq)
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{
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return true;
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}
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static inline bool enic_poll_unlock_napi(struct vnic_rq *rq)
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{
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return false;
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}
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static inline bool enic_poll_lock_poll(struct vnic_rq *rq)
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{
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return false;
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}
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static inline bool enic_poll_unlock_poll(struct vnic_rq *rq)
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{
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return false;
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}
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static inline bool enic_poll_ll_polling(struct vnic_rq *rq)
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{
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return false;
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}
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#endif /* CONFIG_NET_RX_BUSY_POLL */
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void vnic_rq_free(struct vnic_rq *rq);
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int vnic_rq_alloc(struct vnic_dev *vdev, struct vnic_rq *rq, unsigned int index,
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unsigned int desc_count, unsigned int desc_size);
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