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Commit a82a7fcd authored by Mike Marciniszyn's avatar Mike Marciniszyn Committed by Doug Ledford
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IB/hfi1: Process qp wait list in IRQ thread periodically 



In the event that the IRQ thread is extremely busy, the
processing of an rcd wait list can be delayed by quite
a bit until the IRQ thread completes its work.

The QP reset reference count wait can then appear to be stuck, thus
causing up a QP destroy to emit the hung task diagnostic.

Fix by processing the qp wait list periodically from the thread.  The
interval is a multiple (currently 4) of the MAX_PKT_RECV.

Also, reduce some of the excessive inlining.   The guidelines
are per packet is ok inline, otherwise the choice is based on
likelyhood of execution.

Reviewed-by: default avatarSebastian Sanchez <sebastian.sanchez@intel.com>
Reviewed-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 4fcf1de5

drivers/infiniband/hw/hfi1/driver.c

+67 −54
Original line number Diff line number Diff line
@@ -100,6 +100,11 @@ MODULE_VERSION(HFI1_DRIVER_VERSION); 
 * MAX_PKT_RCV is the max # if packets processed per receive interrupt.

 */

#define MAX_PKT_RECV 64

/*

 * MAX_PKT_THREAD_RCV is the max # of packets processed before

 * the qp_wait_list queue is flushed.

 */

#define MAX_PKT_RECV_THREAD (MAX_PKT_RECV * 4)

#define EGR_HEAD_UPDATE_THRESHOLD 16



struct hfi1_ib_stats hfi1_stats;
@@ -259,7 +264,7 @@ static inline void *get_egrbuf(const struct hfi1_ctxtdata *rcd, u64 rhf, 
 * allowed size ranges for the respective type and, optionally,

 * return the proper encoding.

 */

inline int hfi1_rcvbuf_validate(u32 size, u8 type, u16 *encoded)

int hfi1_rcvbuf_validate(u32 size, u8 type, u16 *encoded)

{

	if (unlikely(!PAGE_ALIGNED(size)))

		return 0;
@@ -654,25 +659,69 @@ static void __prescan_rxq(struct hfi1_packet *packet) 
	}

}



static inline int skip_rcv_packet(struct hfi1_packet *packet, int thread)

static void process_rcv_qp_work(struct hfi1_ctxtdata *rcd)

{

	int ret = RCV_PKT_OK;

	struct rvt_qp *qp, *nqp;



	/* Set up for the next packet */

	packet->rhqoff += packet->rsize;

	if (packet->rhqoff >= packet->maxcnt)

		packet->rhqoff = 0;

	/*

	 * Iterate over all QPs waiting to respond.

	 * The list won't change since the IRQ is only run on one CPU.

	 */

	list_for_each_entry_safe(qp, nqp, &rcd->qp_wait_list, rspwait) {

		list_del_init(&qp->rspwait);

		if (qp->r_flags & RVT_R_RSP_NAK) {

			qp->r_flags &= ~RVT_R_RSP_NAK;

			hfi1_send_rc_ack(rcd, qp, 0);

		}

		if (qp->r_flags & RVT_R_RSP_SEND) {

			unsigned long flags;



	packet->numpkt++;

	if (unlikely((packet->numpkt & (MAX_PKT_RECV - 1)) == 0)) {

			qp->r_flags &= ~RVT_R_RSP_SEND;

			spin_lock_irqsave(&qp->s_lock, flags);

			if (ib_rvt_state_ops[qp->state] &

					RVT_PROCESS_OR_FLUSH_SEND)

				hfi1_schedule_send(qp);

			spin_unlock_irqrestore(&qp->s_lock, flags);

		}

		rvt_put_qp(qp);

	}

}



static noinline int max_packet_exceeded(struct hfi1_packet *packet, int thread)

{

	if (thread) {

		if ((packet->numpkt & (MAX_PKT_RECV_THREAD - 1)) == 0)

			/* allow defered processing */

			process_rcv_qp_work(packet->rcd);

		cond_resched();

		return RCV_PKT_OK;

	} else {

			ret = RCV_PKT_LIMIT;

		this_cpu_inc(*packet->rcd->dd->rcv_limit);

		return RCV_PKT_LIMIT;

	}

}



static inline int check_max_packet(struct hfi1_packet *packet, int thread)

{

	int ret = RCV_PKT_OK;



	if (unlikely((packet->numpkt & (MAX_PKT_RECV - 1)) == 0))

		ret = max_packet_exceeded(packet, thread);

	return ret;

}



static noinline int skip_rcv_packet(struct hfi1_packet *packet, int thread)

{

	int ret;



	/* Set up for the next packet */

	packet->rhqoff += packet->rsize;

	if (packet->rhqoff >= packet->maxcnt)

		packet->rhqoff = 0;



	packet->numpkt++;

	ret = check_max_packet(packet, thread);



	packet->rhf_addr = (__le32 *)packet->rcd->rcvhdrq + packet->rhqoff +

				     packet->rcd->dd->rhf_offset;

	packet->rhf = rhf_to_cpu(packet->rhf_addr);
@@ -682,7 +731,7 @@ static inline int skip_rcv_packet(struct hfi1_packet *packet, int thread) 


static inline int process_rcv_packet(struct hfi1_packet *packet, int thread)

{

	int ret = RCV_PKT_OK;

	int ret;



	packet->hdr = hfi1_get_msgheader(packet->rcd->dd,

					 packet->rhf_addr);
@@ -723,14 +772,7 @@ static inline int process_rcv_packet(struct hfi1_packet *packet, int thread) 
	if (packet->rhqoff >= packet->maxcnt)

		packet->rhqoff = 0;



	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);

		}

	}

	ret = check_max_packet(packet, thread);



	packet->rhf_addr = (__le32 *)packet->rcd->rcvhdrq + packet->rhqoff +

				      packet->rcd->dd->rhf_offset;
@@ -767,38 +809,6 @@ static inline void finish_packet(struct hfi1_packet *packet) 
		       packet->etail, rcv_intr_dynamic, packet->numpkt);

}



static inline void process_rcv_qp_work(struct hfi1_packet *packet)

{

	struct hfi1_ctxtdata *rcd;

	struct rvt_qp *qp, *nqp;



	rcd = packet->rcd;

	rcd->head = packet->rhqoff;



	/*

	 * Iterate over all QPs waiting to respond.

	 * The list won't change since the IRQ is only run on one CPU.

	 */

	list_for_each_entry_safe(qp, nqp, &rcd->qp_wait_list, rspwait) {

		list_del_init(&qp->rspwait);

		if (qp->r_flags & RVT_R_RSP_NAK) {

			qp->r_flags &= ~RVT_R_RSP_NAK;

			hfi1_send_rc_ack(rcd, qp, 0);

		}

		if (qp->r_flags & RVT_R_RSP_SEND) {

			unsigned long flags;



			qp->r_flags &= ~RVT_R_RSP_SEND;

			spin_lock_irqsave(&qp->s_lock, flags);

			if (ib_rvt_state_ops[qp->state] &

					RVT_PROCESS_OR_FLUSH_SEND)

				hfi1_schedule_send(qp);

			spin_unlock_irqrestore(&qp->s_lock, flags);

		}

		rvt_put_qp(qp);

	}

}



/*

 * Handle receive interrupts when using the no dma rtail option.

 */
@@ -826,7 +836,8 @@ int handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *rcd, int thread) 
			last = RCV_PKT_DONE;

		process_rcv_update(last, &packet);

	}

	process_rcv_qp_work(&packet);

	process_rcv_qp_work(rcd);

	rcd->head = packet.rhqoff;

bail:

	finish_packet(&packet);

	return last;
@@ -854,7 +865,8 @@ int handle_receive_interrupt_dma_rtail(struct hfi1_ctxtdata *rcd, int thread) 
			last = RCV_PKT_DONE;

		process_rcv_update(last, &packet);

	}

	process_rcv_qp_work(&packet);

	process_rcv_qp_work(rcd);

	rcd->head = packet.rhqoff;

bail:

	finish_packet(&packet);

	return last;
@@ -1024,7 +1036,8 @@ int handle_receive_interrupt(struct hfi1_ctxtdata *rcd, int thread) 
		process_rcv_update(last, &packet);

	}



	process_rcv_qp_work(&packet);

	process_rcv_qp_work(rcd);

	rcd->head = packet.rhqoff;



bail:

	/*