[Intel-wired-lan] [PATCH net-next] ice: Allow operation with reduced device MSI-X
Tony Nguyen
anthony.l.nguyen at intel.com
Mon Aug 22 18:56:54 UTC 2022
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 741106f7bd8d ("ice: Improve
MSI-X fallback logic") and, instead, adjust the MSI-X request to make use
of what is available.
Signed-off-by: Tony Nguyen <anthony.l.nguyen at intel.com>
---
drivers/net/ethernet/intel/ice/ice_main.c | 187 ++++++++++++----------
1 file changed, 102 insertions(+), 85 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 3dbd91d8d83e..ccd08bc947cd 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -3944,88 +3944,137 @@ 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;
+ }
+
+ /* For intermediate operation, 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 */
@@ -4034,38 +4083,11 @@ 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_remain < ICE_MIN_LAN_TXRX_MSIX)
+ v_remain = ICE_MIN_LAN_TXRX_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);
-
- 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);
@@ -4080,12 +4102,7 @@ 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;
--
2.25.1
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