Commit d3b9e8ad authored by Max Gurtovoy's avatar Max Gurtovoy Committed by Jason Gunthorpe
Browse files

RDMA/core: Reduce poll batch for direct cq polling 



Fix warning limit for kernel stack consumption:

drivers/infiniband/core/cq.c: In function 'ib_process_cq_direct':
drivers/infiniband/core/cq.c:78:1: error: the frame size of 1032 bytes
is larger than 1024 bytes [-Werror=frame-larger-than=]

Using smaller ib_wc array on the stack brings us comfortably below that
limit again.

Fixes: 246d8b18 ("IB/cq: Don't force IB_POLL_DIRECT poll context for ib_process_cq_direct")
Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarSergey Gorenko <sergeygo@mellanox.com>
Signed-off-by: default avatarMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Reviewed-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 5d414b17

drivers/infiniband/core/cq.c

+11 −10
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


/* # of WCs to poll for with a single call to ib_poll_cq */

#define IB_POLL_BATCH			16

#define IB_POLL_BATCH_DIRECT		8



/* # of WCs to iterate over before yielding */

#define IB_POLL_BUDGET_IRQ		256
@@ -25,17 +26,17 @@ 
#define IB_POLL_FLAGS \

	(IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS)



static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *poll_wc)

static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *wcs,

			   int batch)

{

	int i, n, completed = 0;

	struct ib_wc *wcs = poll_wc ? : cq->wc;



	/*

	 * budget might be (-1) if the caller does not

	 * want to bound this call, thus we need unsigned

	 * minimum here.

	 */

	while ((n = ib_poll_cq(cq, min_t(u32, IB_POLL_BATCH,

	while ((n = ib_poll_cq(cq, min_t(u32, batch,

					 budget - completed), wcs)) > 0) {

		for (i = 0; i < n; i++) {

			struct ib_wc *wc = &wcs[i];
@@ -48,8 +49,7 @@ static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *poll_wc) 


		completed += n;



		if (n != IB_POLL_BATCH ||

		    (budget != -1 && completed >= budget))

		if (n != batch || (budget != -1 && completed >= budget))

			break;

	}
@@ -72,9 +72,9 @@ static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *poll_wc) 
 */

int ib_process_cq_direct(struct ib_cq *cq, int budget)

{

	struct ib_wc wcs[IB_POLL_BATCH];

	struct ib_wc wcs[IB_POLL_BATCH_DIRECT];



	return __ib_process_cq(cq, budget, wcs);

	return __ib_process_cq(cq, budget, wcs, IB_POLL_BATCH_DIRECT);

}

EXPORT_SYMBOL(ib_process_cq_direct);
@@ -88,7 +88,7 @@ static int ib_poll_handler(struct irq_poll *iop, int budget) 
	struct ib_cq *cq = container_of(iop, struct ib_cq, iop);

	int completed;



	completed = __ib_process_cq(cq, budget, NULL);

	completed = __ib_process_cq(cq, budget, cq->wc, IB_POLL_BATCH);

	if (completed < budget) {

		irq_poll_complete(&cq->iop);

		if (ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)
@@ -108,7 +108,8 @@ static void ib_cq_poll_work(struct work_struct *work) 
	struct ib_cq *cq = container_of(work, struct ib_cq, work);

	int completed;



	completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE, NULL);

	completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE, cq->wc,

				    IB_POLL_BATCH);

	if (completed >= IB_POLL_BUDGET_WORKQUEUE ||

	    ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)

		queue_work(ib_comp_wq, &cq->work);

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