From f4f30031c33cdff10c87d0a56ef575508ed7b54d Mon Sep 17 00:00:00 2001 From: Dean Luick Date: Mon, 26 Oct 2015 10:28:44 -0400 Subject: [PATCH] staging/rdma/hfi1: Thread the receive interrupt. When under heavy load, the receive interrupt handler can run too long with IRQs disabled. Add a mixed-mode threading scheme. Initially process packets in the handler for quick responses (latency). If there are too many packets to process move to a thread to continue (bandwidth). Reviewed-by: Mike Marciniszyn Signed-off-by: Dean Luick Signed-off-by: Ira Weiny Signed-off-by: Greg Kroah-Hartman --- drivers/staging/rdma/hfi1/chip.c | 104 ++++++++++++++++++++++++++--- drivers/staging/rdma/hfi1/driver.c | 72 +++++++++++--------- drivers/staging/rdma/hfi1/hfi.h | 20 ++++-- drivers/staging/rdma/hfi1/sdma.c | 4 +- 4 files changed, 154 insertions(+), 46 deletions(-) diff --git a/drivers/staging/rdma/hfi1/chip.c b/drivers/staging/rdma/hfi1/chip.c index e47420f4786b..e48981994b10 100644 --- a/drivers/staging/rdma/hfi1/chip.c +++ b/drivers/staging/rdma/hfi1/chip.c @@ -4424,7 +4424,7 @@ static void is_rcv_avail_int(struct hfi1_devdata *dd, unsigned int source) rcd = dd->rcd[source]; if (rcd) { if (source < dd->first_user_ctxt) - rcd->do_interrupt(rcd); + rcd->do_interrupt(rcd, 0); else handle_user_interrupt(rcd); return; /* OK */ @@ -4590,23 +4590,106 @@ static irqreturn_t sdma_interrupt(int irq, void *data) } /* - * NOTE: this routine expects to be on its own MSI-X interrupt. If - * multiple receive contexts share the same MSI-X interrupt, then this - * routine must check for who received it. + * Clear the receive interrupt, forcing the write and making sure + * we have data from the chip, pushing everything in front of it + * back to the host. + */ +static inline void clear_recv_intr(struct hfi1_ctxtdata *rcd) +{ + struct hfi1_devdata *dd = rcd->dd; + u32 addr = CCE_INT_CLEAR + (8 * rcd->ireg); + + mmiowb(); /* make sure everything before is written */ + write_csr(dd, addr, rcd->imask); + /* force the above write on the chip and get a value back */ + (void)read_csr(dd, addr); +} + +/* force the receive interrupt */ +static inline void force_recv_intr(struct hfi1_ctxtdata *rcd) +{ + write_csr(rcd->dd, CCE_INT_FORCE + (8 * rcd->ireg), rcd->imask); +} + +/* return non-zero if a packet is present */ +static inline int check_packet_present(struct hfi1_ctxtdata *rcd) +{ + if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) + return (rcd->seq_cnt == + rhf_rcv_seq(rhf_to_cpu(get_rhf_addr(rcd)))); + + /* else is RDMA rtail */ + return (rcd->head != get_rcvhdrtail(rcd)); +} + +/* + * Receive packet IRQ handler. This routine expects to be on its own IRQ. + * This routine will try to handle packets immediately (latency), but if + * it finds too many, it will invoke the thread handler (bandwitdh). The + * chip receive interupt is *not* cleared down until this or the thread (if + * invoked) is finished. The intent is to avoid extra interrupts while we + * are processing packets anyway. */ static irqreturn_t receive_context_interrupt(int irq, void *data) { struct hfi1_ctxtdata *rcd = data; struct hfi1_devdata *dd = rcd->dd; + int disposition; + int present; trace_hfi1_receive_interrupt(dd, rcd->ctxt); this_cpu_inc(*dd->int_counter); - /* clear the interrupt */ - write_csr(rcd->dd, CCE_INT_CLEAR + (8*rcd->ireg), rcd->imask); + /* receive interrupt remains blocked while processing packets */ + disposition = rcd->do_interrupt(rcd, 0); - /* handle the interrupt */ - rcd->do_interrupt(rcd); + /* + * Too many packets were seen while processing packets in this + * IRQ handler. Invoke the handler thread. The receive interrupt + * remains blocked. + */ + if (disposition == RCV_PKT_LIMIT) + return IRQ_WAKE_THREAD; + + /* + * The packet processor detected no more packets. Clear the receive + * interrupt and recheck for a packet packet that may have arrived + * after the previous check and interrupt clear. If a packet arrived, + * force another interrupt. + */ + clear_recv_intr(rcd); + present = check_packet_present(rcd); + if (present) + force_recv_intr(rcd); + + return IRQ_HANDLED; +} + +/* + * Receive packet thread handler. This expects to be invoked with the + * receive interrupt still blocked. + */ +static irqreturn_t receive_context_thread(int irq, void *data) +{ + struct hfi1_ctxtdata *rcd = data; + int present; + + /* receive interrupt is still blocked from the IRQ handler */ + (void)rcd->do_interrupt(rcd, 1); + + /* + * The packet processor will only return if it detected no more + * packets. Hold IRQs here so we can safely clear the interrupt and + * recheck for a packet that may have arrived after the previous + * check and the interrupt clear. If a packet arrived, force another + * interrupt. + */ + local_irq_disable(); + clear_recv_intr(rcd); + present = check_packet_present(rcd); + if (present) + force_recv_intr(rcd); + local_irq_enable(); return IRQ_HANDLED; } @@ -8858,6 +8941,7 @@ static int request_msix_irqs(struct hfi1_devdata *dd) struct hfi1_msix_entry *me = &dd->msix_entries[i]; const char *err_info; irq_handler_t handler; + irq_handler_t thread = NULL; void *arg; int idx; struct hfi1_ctxtdata *rcd = NULL; @@ -8894,6 +8978,7 @@ static int request_msix_irqs(struct hfi1_devdata *dd) rcd->imask = ((u64)1) << ((IS_RCVAVAIL_START+idx) % 64); handler = receive_context_interrupt; + thread = receive_context_thread; arg = rcd; snprintf(me->name, sizeof(me->name), DRIVER_NAME"_%d kctxt%d", dd->unit, idx); @@ -8912,7 +8997,8 @@ static int request_msix_irqs(struct hfi1_devdata *dd) /* make sure the name is terminated */ me->name[sizeof(me->name)-1] = 0; - ret = request_irq(me->msix.vector, handler, 0, me->name, arg); + ret = request_threaded_irq(me->msix.vector, handler, thread, 0, + me->name, arg); if (ret) { dd_dev_err(dd, "unable to allocate %s interrupt, vector %d, index %d, err %d\n", diff --git a/drivers/staging/rdma/hfi1/driver.c b/drivers/staging/rdma/hfi1/driver.c index ee4a01f71e8d..ce69141b56cb 100644 --- a/drivers/staging/rdma/hfi1/driver.c +++ b/drivers/staging/rdma/hfi1/driver.c @@ -427,8 +427,7 @@ static inline void init_packet(struct hfi1_ctxtdata *rcd, packet->rcd = rcd; packet->updegr = 0; packet->etail = -1; - packet->rhf_addr = (__le32 *) rcd->rcvhdrq + rcd->head + - rcd->dd->rhf_offset; + packet->rhf_addr = get_rhf_addr(rcd); packet->rhf = rhf_to_cpu(packet->rhf_addr); packet->rhqoff = rcd->head; packet->numpkt = 0; @@ -619,10 +618,7 @@ next: } #endif /* CONFIG_PRESCAN_RXQ */ -#define RCV_PKT_OK 0x0 -#define RCV_PKT_MAX 0x1 - -static inline int process_rcv_packet(struct hfi1_packet *packet) +static inline int process_rcv_packet(struct hfi1_packet *packet, int thread) { int ret = RCV_PKT_OK; @@ -664,9 +660,13 @@ static inline int process_rcv_packet(struct hfi1_packet *packet) if (packet->rhqoff >= packet->maxcnt) packet->rhqoff = 0; - if (packet->numpkt == MAX_PKT_RECV) { - ret = RCV_PKT_MAX; - this_cpu_inc(*packet->rcd->dd->rcv_limit); + if (unlikely((packet->numpkt & (MAX_PKT_RECV - 1)) == 0)) { + if (thread) { + cond_resched(); + } else { + ret = RCV_PKT_LIMIT; + this_cpu_inc(*packet->rcd->dd->rcv_limit); + } } packet->rhf_addr = (__le32 *) packet->rcd->rcvhdrq + packet->rhqoff + @@ -743,57 +743,63 @@ static inline void process_rcv_qp_work(struct hfi1_packet *packet) /* * Handle receive interrupts when using the no dma rtail option. */ -void handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *rcd) +int handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *rcd, int thread) { u32 seq; - int last = 0; + int last = RCV_PKT_OK; struct hfi1_packet packet; init_packet(rcd, &packet); seq = rhf_rcv_seq(packet.rhf); - if (seq != rcd->seq_cnt) + if (seq != rcd->seq_cnt) { + last = RCV_PKT_DONE; goto bail; + } prescan_rxq(&packet); - while (!last) { - last = process_rcv_packet(&packet); + while (last == RCV_PKT_OK) { + last = process_rcv_packet(&packet, thread); seq = rhf_rcv_seq(packet.rhf); if (++rcd->seq_cnt > 13) rcd->seq_cnt = 1; if (seq != rcd->seq_cnt) - last = 1; + last = RCV_PKT_DONE; process_rcv_update(last, &packet); } process_rcv_qp_work(&packet); bail: finish_packet(&packet); + return last; } -void handle_receive_interrupt_dma_rtail(struct hfi1_ctxtdata *rcd) +int handle_receive_interrupt_dma_rtail(struct hfi1_ctxtdata *rcd, int thread) { u32 hdrqtail; - int last = 0; + int last = RCV_PKT_OK; struct hfi1_packet packet; init_packet(rcd, &packet); hdrqtail = get_rcvhdrtail(rcd); - if (packet.rhqoff == hdrqtail) + if (packet.rhqoff == hdrqtail) { + last = RCV_PKT_DONE; goto bail; + } smp_rmb(); /* prevent speculative reads of dma'ed hdrq */ prescan_rxq(&packet); - while (!last) { - last = process_rcv_packet(&packet); + while (last == RCV_PKT_OK) { + last = process_rcv_packet(&packet, thread); + hdrqtail = get_rcvhdrtail(rcd); if (packet.rhqoff == hdrqtail) - last = 1; + last = RCV_PKT_DONE; process_rcv_update(last, &packet); } process_rcv_qp_work(&packet); bail: finish_packet(&packet); - + return last; } static inline void set_all_nodma_rtail(struct hfi1_devdata *dd) @@ -821,12 +827,11 @@ static inline void set_all_dma_rtail(struct hfi1_devdata *dd) * Called from interrupt handler for errors or receive interrupt. * This is the slow path interrupt handler. */ -void handle_receive_interrupt(struct hfi1_ctxtdata *rcd) +int handle_receive_interrupt(struct hfi1_ctxtdata *rcd, int thread) { - struct hfi1_devdata *dd = rcd->dd; u32 hdrqtail; - int last = 0, needset = 1; + int last = RCV_PKT_OK, needset = 1; struct hfi1_packet packet; init_packet(rcd, &packet); @@ -834,19 +839,23 @@ void handle_receive_interrupt(struct hfi1_ctxtdata *rcd) if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) { u32 seq = rhf_rcv_seq(packet.rhf); - if (seq != rcd->seq_cnt) + if (seq != rcd->seq_cnt) { + last = RCV_PKT_DONE; goto bail; + } hdrqtail = 0; } else { hdrqtail = get_rcvhdrtail(rcd); - if (packet.rhqoff == hdrqtail) + if (packet.rhqoff == hdrqtail) { + last = RCV_PKT_DONE; goto bail; + } smp_rmb(); /* prevent speculative reads of dma'ed hdrq */ } prescan_rxq(&packet); - while (!last) { + while (last == RCV_PKT_OK) { if (unlikely(dd->do_drop && atomic_xchg(&dd->drop_packet, DROP_PACKET_OFF) == DROP_PACKET_ON)) { @@ -860,7 +869,7 @@ void handle_receive_interrupt(struct hfi1_ctxtdata *rcd) packet.rhf = rhf_to_cpu(packet.rhf_addr); } else { - last = process_rcv_packet(&packet); + last = process_rcv_packet(&packet, thread); } if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) { @@ -869,7 +878,7 @@ void handle_receive_interrupt(struct hfi1_ctxtdata *rcd) if (++rcd->seq_cnt > 13) rcd->seq_cnt = 1; if (seq != rcd->seq_cnt) - last = 1; + last = RCV_PKT_DONE; if (needset) { dd_dev_info(dd, "Switching to NO_DMA_RTAIL\n"); @@ -878,7 +887,7 @@ void handle_receive_interrupt(struct hfi1_ctxtdata *rcd) } } else { if (packet.rhqoff == hdrqtail) - last = 1; + last = RCV_PKT_DONE; if (needset) { dd_dev_info(dd, "Switching to DMA_RTAIL\n"); @@ -898,6 +907,7 @@ bail: * if no packets were processed. */ finish_packet(&packet); + return last; } /* diff --git a/drivers/staging/rdma/hfi1/hfi.h b/drivers/staging/rdma/hfi1/hfi.h index a35213e9b500..190f7a2f6773 100644 --- a/drivers/staging/rdma/hfi1/hfi.h +++ b/drivers/staging/rdma/hfi1/hfi.h @@ -313,7 +313,7 @@ struct hfi1_ctxtdata { * be valid. Worst case is we process an extra interrupt and up to 64 * packets with the wrong interrupt handler. */ - void (*do_interrupt)(struct hfi1_ctxtdata *rcd); + int (*do_interrupt)(struct hfi1_ctxtdata *rcd, int threaded); }; /* @@ -1130,9 +1130,21 @@ void hfi1_init_pportdata(struct pci_dev *, struct hfi1_pportdata *, struct hfi1_devdata *, u8, u8); void hfi1_free_ctxtdata(struct hfi1_devdata *, struct hfi1_ctxtdata *); -void handle_receive_interrupt(struct hfi1_ctxtdata *); -void handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *rcd); -void handle_receive_interrupt_dma_rtail(struct hfi1_ctxtdata *rcd); +int handle_receive_interrupt(struct hfi1_ctxtdata *, int); +int handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *, int); +int handle_receive_interrupt_dma_rtail(struct hfi1_ctxtdata *, int); + +/* receive packet handler dispositions */ +#define RCV_PKT_OK 0x0 /* keep going */ +#define RCV_PKT_LIMIT 0x1 /* stop, hit limit, start thread */ +#define RCV_PKT_DONE 0x2 /* stop, no more packets detected */ + +/* calculate the current RHF address */ +static inline __le32 *get_rhf_addr(struct hfi1_ctxtdata *rcd) +{ + return (__le32 *)rcd->rcvhdrq + rcd->head + rcd->dd->rhf_offset; +} + int hfi1_reset_device(int); /* return the driver's idea of the logical OPA port state */ diff --git a/drivers/staging/rdma/hfi1/sdma.c b/drivers/staging/rdma/hfi1/sdma.c index f372b6d00e9d..2a1da2189900 100644 --- a/drivers/staging/rdma/hfi1/sdma.c +++ b/drivers/staging/rdma/hfi1/sdma.c @@ -2096,9 +2096,9 @@ unlock_noconn: tx->sn = sde->tail_sn++; trace_hfi1_sdma_in_sn(sde, tx->sn); #endif - spin_lock_irqsave(&sde->flushlist_lock, flags); + spin_lock(&sde->flushlist_lock); list_add_tail(&tx->list, &sde->flushlist); - spin_unlock_irqrestore(&sde->flushlist_lock, flags); + spin_unlock(&sde->flushlist_lock); if (wait) { wait->tx_count++; wait->count += tx->num_desc; -- 2.20.1