Commit ce462613 authored by Tony Nguyen's avatar Tony Nguyen
Browse files

ice: Allow operation with reduced device MSI-X 



The driver currently takes an all or nothing approach for device MSI-X
vectors. Meaning if it does not get its full allocation, it will fail and
not load. There is no reason it can't work with a reduced number of MSI-X
vectors. Take a similar approach as commit 741106f7 ("ice: Improve
MSI-X fallback logic") and, instead, adjust the MSI-X request to make use
of what is available.

Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: default avatarPetr Oros <poros@redhat.com>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
parent 03fdb11d

drivers/net/ethernet/intel/ice/ice_main.c

+100 −85
Original line number Diff line number Diff line
@@ -3921,88 +3921,135 @@ static int ice_init_pf(struct ice_pf *pf) 
	return 0;

}



/**

 * ice_reduce_msix_usage - Reduce usage of MSI-X vectors

 * @pf: board private structure

 * @v_remain: number of remaining MSI-X vectors to be distributed

 *

 * Reduce the usage of MSI-X vectors when entire request cannot be fulfilled.

 * pf->num_lan_msix and pf->num_rdma_msix values are set based on number of

 * remaining vectors.

 */

static void ice_reduce_msix_usage(struct ice_pf *pf, int v_remain)

{

	int v_rdma;



	if (!ice_is_rdma_ena(pf)) {

		pf->num_lan_msix = v_remain;

		return;

	}



	/* RDMA needs at least 1 interrupt in addition to AEQ MSIX */

	v_rdma = ICE_RDMA_NUM_AEQ_MSIX + 1;



	if (v_remain < ICE_MIN_LAN_TXRX_MSIX + ICE_MIN_RDMA_MSIX) {

		dev_warn(ice_pf_to_dev(pf), "Not enough MSI-X vectors to support RDMA.\n");

		clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);



		pf->num_rdma_msix = 0;

		pf->num_lan_msix = ICE_MIN_LAN_TXRX_MSIX;

	} else if ((v_remain < ICE_MIN_LAN_TXRX_MSIX + v_rdma) ||

		   (v_remain - v_rdma < v_rdma)) {

		/* Support minimum RDMA and give remaining vectors to LAN MSIX */

		pf->num_rdma_msix = ICE_MIN_RDMA_MSIX;

		pf->num_lan_msix = v_remain - ICE_MIN_RDMA_MSIX;

	} else {

		/* Split remaining MSIX with RDMA after accounting for AEQ MSIX

		 */

		pf->num_rdma_msix = (v_remain - ICE_RDMA_NUM_AEQ_MSIX) / 2 +

				    ICE_RDMA_NUM_AEQ_MSIX;

		pf->num_lan_msix = v_remain - pf->num_rdma_msix;

	}

}



/**

 * ice_ena_msix_range - Request a range of MSIX vectors from the OS

 * @pf: board private structure

 *

 * compute the number of MSIX vectors required (v_budget) and request from

 * the OS. Return the number of vectors reserved or negative on failure

 * Compute the number of MSIX vectors wanted and request from the OS. Adjust

 * device usage if there are not enough vectors. Return the number of vectors

 * reserved or negative on failure.

 */

static int ice_ena_msix_range(struct ice_pf *pf)

{

	int num_cpus, v_left, v_actual, v_other, v_budget = 0;

	int num_cpus, hw_num_msix, v_other, v_wanted, v_actual;

	struct device *dev = ice_pf_to_dev(pf);

	int needed, err, i;

	int err, i;



	v_left = pf->hw.func_caps.common_cap.num_msix_vectors;

	hw_num_msix = pf->hw.func_caps.common_cap.num_msix_vectors;

	num_cpus = num_online_cpus();



	/* reserve for LAN miscellaneous handler */

	needed = ICE_MIN_LAN_OICR_MSIX;

	if (v_left < needed)

		goto no_hw_vecs_left_err;

	v_budget += needed;

	v_left -= needed;

	/* LAN miscellaneous handler */

	v_other = ICE_MIN_LAN_OICR_MSIX;



	/* reserve for flow director */

	if (test_bit(ICE_FLAG_FD_ENA, pf->flags)) {

		needed = ICE_FDIR_MSIX;

		if (v_left < needed)

			goto no_hw_vecs_left_err;

		v_budget += needed;

		v_left -= needed;

	}



	/* reserve for switchdev */

	needed = ICE_ESWITCH_MSIX;

	if (v_left < needed)

		goto no_hw_vecs_left_err;

	v_budget += needed;

	v_left -= needed;



	/* total used for non-traffic vectors */

	v_other = v_budget;



	/* reserve vectors for LAN traffic */

	needed = num_cpus;

	if (v_left < needed)

		goto no_hw_vecs_left_err;

	pf->num_lan_msix = needed;

	v_budget += needed;

	v_left -= needed;



	/* reserve vectors for RDMA auxiliary driver */

	/* Flow Director */

	if (test_bit(ICE_FLAG_FD_ENA, pf->flags))

		v_other += ICE_FDIR_MSIX;



	/* switchdev */

	v_other += ICE_ESWITCH_MSIX;



	v_wanted = v_other;



	/* LAN traffic */

	pf->num_lan_msix = num_cpus;

	v_wanted += pf->num_lan_msix;



	/* RDMA auxiliary driver */

	if (ice_is_rdma_ena(pf)) {

		needed = num_cpus + ICE_RDMA_NUM_AEQ_MSIX;

		if (v_left < needed)

			goto no_hw_vecs_left_err;

		pf->num_rdma_msix = needed;

		v_budget += needed;

		v_left -= needed;

		pf->num_rdma_msix = num_cpus + ICE_RDMA_NUM_AEQ_MSIX;

		v_wanted += pf->num_rdma_msix;

	}



	if (v_wanted > hw_num_msix) {

		int v_remain;



		dev_warn(dev, "not enough device MSI-X vectors. wanted = %d, available = %d\n",

			 v_wanted, hw_num_msix);



		if (hw_num_msix < ICE_MIN_MSIX) {

			err = -ERANGE;

			goto exit_err;

		}



		v_remain = hw_num_msix - v_other;

		if (v_remain < ICE_MIN_LAN_TXRX_MSIX) {

			v_other = ICE_MIN_MSIX - ICE_MIN_LAN_TXRX_MSIX;

			v_remain = ICE_MIN_LAN_TXRX_MSIX;

		}



		ice_reduce_msix_usage(pf, v_remain);

		v_wanted = pf->num_lan_msix + pf->num_rdma_msix + v_other;



		dev_notice(dev, "Reducing request to %d MSI-X vectors for LAN traffic.\n",

			   pf->num_lan_msix);

		if (ice_is_rdma_ena(pf))

			dev_notice(dev, "Reducing request to %d MSI-X vectors for RDMA.\n",

				   pf->num_rdma_msix);

	}



	pf->msix_entries = devm_kcalloc(dev, v_budget,

	pf->msix_entries = devm_kcalloc(dev, v_wanted,

					sizeof(*pf->msix_entries), GFP_KERNEL);

	if (!pf->msix_entries) {

		err = -ENOMEM;

		goto exit_err;

	}



	for (i = 0; i < v_budget; i++)

	for (i = 0; i < v_wanted; i++)

		pf->msix_entries[i].entry = i;



	/* actually reserve the vectors */

	v_actual = pci_enable_msix_range(pf->pdev, pf->msix_entries,

					 ICE_MIN_MSIX, v_budget);

					 ICE_MIN_MSIX, v_wanted);

	if (v_actual < 0) {

		dev_err(dev, "unable to reserve MSI-X vectors\n");

		err = v_actual;

		goto msix_err;

	}



	if (v_actual < v_budget) {

	if (v_actual < v_wanted) {

		dev_warn(dev, "not enough OS MSI-X vectors. requested = %d, obtained = %d\n",

			 v_budget, v_actual);

			 v_wanted, v_actual);



		if (v_actual < ICE_MIN_MSIX) {

			/* error if we can't get minimum vectors */
@@ -4011,38 +4058,11 @@ static int ice_ena_msix_range(struct ice_pf *pf) 
			goto msix_err;

		} else {

			int v_remain = v_actual - v_other;

			int v_rdma = 0, v_min_rdma = 0;



			if (ice_is_rdma_ena(pf)) {

				/* Need at least 1 interrupt in addition to

				 * AEQ MSIX

				 */

				v_rdma = ICE_RDMA_NUM_AEQ_MSIX + 1;

				v_min_rdma = ICE_MIN_RDMA_MSIX;

			}



			if (v_actual == ICE_MIN_MSIX ||

			    v_remain < ICE_MIN_LAN_TXRX_MSIX + v_min_rdma) {

				dev_warn(dev, "Not enough MSI-X vectors to support RDMA.\n");

				clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);

			if (v_remain < ICE_MIN_LAN_TXRX_MSIX)

				v_remain = ICE_MIN_LAN_TXRX_MSIX;



				pf->num_rdma_msix = 0;

				pf->num_lan_msix = ICE_MIN_LAN_TXRX_MSIX;

			} else if ((v_remain < ICE_MIN_LAN_TXRX_MSIX + v_rdma) ||

				   (v_remain - v_rdma < v_rdma)) {

				/* Support minimum RDMA and give remaining

				 * vectors to LAN MSIX

				 */

				pf->num_rdma_msix = v_min_rdma;

				pf->num_lan_msix = v_remain - v_min_rdma;

			} else {

				/* Split remaining MSIX with RDMA after

				 * accounting for AEQ MSIX

				 */

				pf->num_rdma_msix = (v_remain - ICE_RDMA_NUM_AEQ_MSIX) / 2 +

						    ICE_RDMA_NUM_AEQ_MSIX;

				pf->num_lan_msix = v_remain - pf->num_rdma_msix;

			}

			ice_reduce_msix_usage(pf, v_remain);



			dev_notice(dev, "Enabled %d MSI-X vectors for LAN traffic.\n",

				   pf->num_lan_msix);
@@ -4057,12 +4077,7 @@ static int ice_ena_msix_range(struct ice_pf *pf) 


msix_err:

	devm_kfree(dev, pf->msix_entries);

	goto exit_err;



no_hw_vecs_left_err:

	dev_err(dev, "not enough device MSI-X vectors. requested = %d, available = %d\n",

		needed, v_left);

	err = -ERANGE;

exit_err:

	pf->num_rdma_msix = 0;

	pf->num_lan_msix = 0;