From: Govindarajulu Varadarajan <_govind@gmx.com> Date: Mon, 23 Jun 2014 10:38:04 +0000 (+0530) Subject: enic: add low latency socket busy_poll support X-Git-Tag: v3.17-rc1~106^2~270^2~1 X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=14747cd977195a8aae13d0b1ad021e33c8786afe 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 --- diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c index 5448df2d78c2..d4918eef5050 100644 --- a/drivers/net/ethernet/cisco/enic/enic_main.c +++ b/drivers/net/ethernet/cisco/enic/enic_main.c @@ -42,6 +42,9 @@ #ifdef CONFIG_RFS_ACCEL #include #endif +#ifdef CONFIG_NET_RX_BUSY_POLL +#include +#endif #include "cq_enet_desc.h" #include "vnic_dev.h" @@ -1053,10 +1056,12 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq, if (vlan_stripped) __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tci); - if (netdev->features & NETIF_F_GRO) - napi_gro_receive(&enic->napi[q_number], skb); - else + skb_mark_napi_id(skb, &enic->napi[rq->index]); + if (enic_poll_busy_polling(rq) || + !(netdev->features & NETIF_F_GRO)) netif_receive_skb(skb); + else + napi_gro_receive(&enic->napi[q_number], skb); if (enic->rx_coalesce_setting.use_adaptive_rx_coalesce) enic_intr_update_pkt_size(&cq->pkt_size_counter, bytes_written); @@ -1093,16 +1098,22 @@ static int enic_poll(struct napi_struct *napi, int budget) unsigned int work_done, rq_work_done = 0, wq_work_done; int err; - /* Service RQ (first) and WQ - */ + wq_work_done = vnic_cq_service(&enic->cq[cq_wq], wq_work_to_do, + enic_wq_service, NULL); + + if (!enic_poll_lock_napi(&enic->rq[cq_rq])) { + if (wq_work_done > 0) + vnic_intr_return_credits(&enic->intr[intr], + wq_work_done, + 0 /* dont unmask intr */, + 0 /* dont reset intr timer */); + return rq_work_done; + } if (budget > 0) rq_work_done = vnic_cq_service(&enic->cq[cq_rq], rq_work_to_do, enic_rq_service, NULL); - wq_work_done = vnic_cq_service(&enic->cq[cq_wq], - wq_work_to_do, enic_wq_service, NULL); - /* Accumulate intr event credits for this polling * cycle. An intr event is the completion of a * a WQ or RQ packet. @@ -1134,6 +1145,7 @@ static int enic_poll(struct napi_struct *napi, int budget) napi_complete(napi); vnic_intr_unmask(&enic->intr[intr]); } + enic_poll_unlock_napi(&enic->rq[cq_rq]); return rq_work_done; } @@ -1234,6 +1246,34 @@ static void enic_set_rx_cpu_rmap(struct enic *enic) #endif /* CONFIG_RFS_ACCEL */ +#ifdef CONFIG_NET_RX_BUSY_POLL +int enic_busy_poll(struct napi_struct *napi) +{ + struct net_device *netdev = napi->dev; + struct enic *enic = netdev_priv(netdev); + unsigned int rq = (napi - &enic->napi[0]); + unsigned int cq = enic_cq_rq(enic, rq); + unsigned int intr = enic_msix_rq_intr(enic, rq); + unsigned int work_to_do = -1; /* clean all pkts possible */ + unsigned int work_done; + + if (!enic_poll_lock_poll(&enic->rq[rq])) + return LL_FLUSH_BUSY; + work_done = vnic_cq_service(&enic->cq[cq], work_to_do, + enic_rq_service, NULL); + + if (work_done > 0) + vnic_intr_return_credits(&enic->intr[intr], + work_done, 0, 0); + vnic_rq_fill(&enic->rq[rq], enic_rq_alloc_buf); + if (enic->rx_coalesce_setting.use_adaptive_rx_coalesce) + enic_calc_int_moderation(enic, &enic->rq[rq]); + enic_poll_unlock_poll(&enic->rq[rq]); + + return work_done; +} +#endif /* CONFIG_NET_RX_BUSY_POLL */ + static int enic_poll_msix(struct napi_struct *napi, int budget) { struct net_device *netdev = napi->dev; @@ -1245,6 +1285,8 @@ static int enic_poll_msix(struct napi_struct *napi, int budget) unsigned int work_done = 0; int err; + if (!enic_poll_lock_napi(&enic->rq[rq])) + return work_done; /* Service RQ */ @@ -1290,6 +1332,7 @@ static int enic_poll_msix(struct napi_struct *napi, int budget) enic_set_int_moderation(enic, &enic->rq[rq]); vnic_intr_unmask(&enic->intr[intr]); } + enic_poll_unlock_napi(&enic->rq[rq]); return work_done; } @@ -1538,8 +1581,10 @@ static int enic_open(struct net_device *netdev) netif_tx_wake_all_queues(netdev); - for (i = 0; i < enic->rq_count; i++) + for (i = 0; i < enic->rq_count; i++) { + enic_busy_poll_init_lock(&enic->rq[i]); napi_enable(&enic->napi[i]); + } enic_dev_enable(enic); @@ -1578,8 +1623,13 @@ static int enic_stop(struct net_device *netdev) enic_dev_disable(enic); - for (i = 0; i < enic->rq_count; i++) + local_bh_disable(); + for (i = 0; i < enic->rq_count; i++) { napi_disable(&enic->napi[i]); + while (!enic_poll_lock_napi(&enic->rq[i])) + mdelay(1); + } + local_bh_enable(); netif_carrier_off(netdev); netif_tx_disable(netdev); @@ -2070,6 +2120,9 @@ static const struct net_device_ops enic_netdev_dynamic_ops = { #ifdef CONFIG_RFS_ACCEL .ndo_rx_flow_steer = enic_rx_flow_steer, #endif +#ifdef CONFIG_NET_RX_BUSY_POLL + .ndo_busy_poll = enic_busy_poll, +#endif }; static const struct net_device_ops enic_netdev_ops = { @@ -2093,14 +2146,19 @@ static const struct net_device_ops enic_netdev_ops = { #ifdef CONFIG_RFS_ACCEL .ndo_rx_flow_steer = enic_rx_flow_steer, #endif +#ifdef CONFIG_NET_RX_BUSY_POLL + .ndo_busy_poll = enic_busy_poll, +#endif }; static void enic_dev_deinit(struct enic *enic) { unsigned int i; - for (i = 0; i < enic->rq_count; i++) + for (i = 0; i < enic->rq_count; i++) { + napi_hash_del(&enic->napi[i]); netif_napi_del(&enic->napi[i]); + } enic_free_vnic_resources(enic); enic_clear_intr_mode(enic); @@ -2166,11 +2224,14 @@ static int enic_dev_init(struct enic *enic) switch (vnic_dev_get_intr_mode(enic->vdev)) { default: netif_napi_add(netdev, &enic->napi[0], enic_poll, 64); + napi_hash_add(&enic->napi[0]); break; case VNIC_DEV_INTR_MODE_MSIX: - for (i = 0; i < enic->rq_count; i++) + for (i = 0; i < enic->rq_count; i++) { netif_napi_add(netdev, &enic->napi[i], enic_poll_msix, 64); + napi_hash_add(&enic->napi[i]); + } break; } diff --git a/drivers/net/ethernet/cisco/enic/vnic_rq.h b/drivers/net/ethernet/cisco/enic/vnic_rq.h index ee7bc95af278..8111d5202df2 100644 --- a/drivers/net/ethernet/cisco/enic/vnic_rq.h +++ b/drivers/net/ethernet/cisco/enic/vnic_rq.h @@ -85,6 +85,21 @@ struct vnic_rq { struct vnic_rq_buf *to_clean; void *os_buf_head; unsigned int pkts_outstanding; +#ifdef CONFIG_NET_RX_BUSY_POLL +#define ENIC_POLL_STATE_IDLE 0 +#define ENIC_POLL_STATE_NAPI (1 << 0) /* NAPI owns this poll */ +#define ENIC_POLL_STATE_POLL (1 << 1) /* poll owns this poll */ +#define ENIC_POLL_STATE_NAPI_YIELD (1 << 2) /* NAPI yielded this poll */ +#define ENIC_POLL_STATE_POLL_YIELD (1 << 3) /* poll yielded this poll */ +#define ENIC_POLL_YIELD (ENIC_POLL_STATE_NAPI_YIELD | \ + ENIC_POLL_STATE_POLL_YIELD) +#define ENIC_POLL_LOCKED (ENIC_POLL_STATE_NAPI | \ + ENIC_POLL_STATE_POLL) +#define ENIC_POLL_USER_PEND (ENIC_POLL_STATE_POLL | \ + ENIC_POLL_STATE_POLL_YIELD) + unsigned int bpoll_state; + spinlock_t bpoll_lock; +#endif /* CONFIG_NET_RX_BUSY_POLL */ }; static inline unsigned int vnic_rq_desc_avail(struct vnic_rq *rq) @@ -197,6 +212,113 @@ static inline int vnic_rq_fill(struct vnic_rq *rq, return 0; } +#ifdef CONFIG_NET_RX_BUSY_POLL +static inline void enic_busy_poll_init_lock(struct vnic_rq *rq) +{ + spin_lock_init(&rq->bpoll_lock); + rq->bpoll_state = ENIC_POLL_STATE_IDLE; +} + +static inline bool enic_poll_lock_napi(struct vnic_rq *rq) +{ + bool rc = true; + + spin_lock(&rq->bpoll_lock); + if (rq->bpoll_state & ENIC_POLL_LOCKED) { + WARN_ON(rq->bpoll_state & ENIC_POLL_STATE_NAPI); + rq->bpoll_state |= ENIC_POLL_STATE_NAPI_YIELD; + rc = false; + } else { + rq->bpoll_state = ENIC_POLL_STATE_NAPI; + } + spin_unlock(&rq->bpoll_lock); + + return rc; +} + +static inline bool enic_poll_unlock_napi(struct vnic_rq *rq) +{ + bool rc = false; + + spin_lock(&rq->bpoll_lock); + WARN_ON(rq->bpoll_state & + (ENIC_POLL_STATE_POLL | ENIC_POLL_STATE_NAPI_YIELD)); + if (rq->bpoll_state & ENIC_POLL_STATE_POLL_YIELD) + rc = true; + rq->bpoll_state = ENIC_POLL_STATE_IDLE; + spin_unlock(&rq->bpoll_lock); + + return rc; +} + +static inline bool enic_poll_lock_poll(struct vnic_rq *rq) +{ + bool rc = true; + + spin_lock_bh(&rq->bpoll_lock); + if (rq->bpoll_state & ENIC_POLL_LOCKED) { + rq->bpoll_state |= ENIC_POLL_STATE_POLL_YIELD; + rc = false; + } else { + rq->bpoll_state |= ENIC_POLL_STATE_POLL; + } + spin_unlock_bh(&rq->bpoll_lock); + + return rc; +} + +static inline bool enic_poll_unlock_poll(struct vnic_rq *rq) +{ + bool rc = false; + + spin_lock_bh(&rq->bpoll_lock); + WARN_ON(rq->bpoll_state & ENIC_POLL_STATE_NAPI); + if (rq->bpoll_state & ENIC_POLL_STATE_POLL_YIELD) + rc = true; + rq->bpoll_state = ENIC_POLL_STATE_IDLE; + spin_unlock_bh(&rq->bpoll_lock); + + return rc; +} + +static inline bool enic_poll_busy_polling(struct vnic_rq *rq) +{ + WARN_ON(!(rq->bpoll_state & ENIC_POLL_LOCKED)); + return rq->bpoll_state & ENIC_POLL_USER_PEND; +} + +#else + +static inline void enic_busy_poll_init_lock(struct vnic_rq *rq) +{ +} + +static inline bool enic_poll_lock_napi(struct vnic_rq *rq) +{ + return true; +} + +static inline bool enic_poll_unlock_napi(struct vnic_rq *rq) +{ + return false; +} + +static inline bool enic_poll_lock_poll(struct vnic_rq *rq) +{ + return false; +} + +static inline bool enic_poll_unlock_poll(struct vnic_rq *rq) +{ + return false; +} + +static inline bool enic_poll_ll_polling(struct vnic_rq *rq) +{ + return false; +} +#endif /* CONFIG_NET_RX_BUSY_POLL */ + void vnic_rq_free(struct vnic_rq *rq); int vnic_rq_alloc(struct vnic_dev *vdev, struct vnic_rq *rq, unsigned int index, unsigned int desc_count, unsigned int desc_size);