diff mbox series

[7/9] ice: use irq_update_affinity_hint()

Message ID 20240603-next-2024-06-03-intel-next-batch-v1-7-e0523b28f325@intel.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Intel Wired LAN Driver Updates 2024-06-03 | expand

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Context Check Description
netdev/series_format warning Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 901 this patch: 901
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 5 maintainers not CCed: pabeni@redhat.com edumazet@google.com anthony.l.nguyen@intel.com jesse.brandeburg@intel.com intel-wired-lan@lists.osuosl.org
netdev/build_clang success Errors and warnings before: 905 this patch: 905
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 905 this patch: 905
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 26 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 188 this patch: 188
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-06-04--18-00 (tests: 1045)

Commit Message

Jacob Keller June 3, 2024, 10:38 p.m. UTC 
From: Michal Schmidt <mschmidt@redhat.com>

irq_set_affinity_hint() is deprecated. Use irq_update_affinity_hint()
instead. This removes the side-effect of actually applying the affinity.

The driver does not really need to worry about spreading its IRQs across
CPUs. The core code already takes care of that.
On the contrary, when the driver applies affinities by itself, it breaks
the users' expectations:
 1. The user configures irqbalance with IRQBALANCE_BANNED_CPULIST in
    order to prevent IRQs from being moved to certain CPUs that run a
    real-time workload.
 2. ice reconfigures VSIs at runtime due to a MIB change
    (ice_dcb_process_lldp_set_mib_change). Reopening a VSI resets the
    affinity in ice_vsi_req_irq_msix().
 3. ice has no idea about irqbalance's config, so it may move an IRQ to
    a banned CPU. The real-time workload suffers unacceptable latency.

I am not sure if updating the affinity hints is at all useful, because
irqbalance ignores them since 2016 ([1]), but at least it's harmless.

This ice change is similar to i40e commit d34c54d1739c ("i40e: Use
irq_update_affinity_hint()").

[1] https://github.com/Irqbalance/irqbalance/commit/dcc411e7bfdd

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Sunil Goutham <sgoutham@marvell.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_lib.c  | 4 ++--
 drivers/net/ethernet/intel/ice/ice_main.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 5371e91f6bbb..0f8b622db2b5 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2587,8 +2587,8 @@  void ice_vsi_free_irq(struct ice_vsi *vsi)
 		if (!IS_ENABLED(CONFIG_RFS_ACCEL))
 			irq_set_affinity_notifier(irq_num, NULL);
 
-		/* clear the affinity_mask in the IRQ descriptor */
-		irq_set_affinity_hint(irq_num, NULL);
+		/* clear the affinity_hint in the IRQ descriptor */
+		irq_update_affinity_hint(irq_num, NULL);
 		synchronize_irq(irq_num);
 		devm_free_irq(ice_pf_to_dev(pf), irq_num, vsi->q_vectors[i]);
 	}
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index f60c022f7960..a5d369b8fed5 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2607,7 +2607,7 @@  static int ice_vsi_req_irq_msix(struct ice_vsi *vsi, char *basename)
 		}
 
 		/* assign the mask for this irq */
-		irq_set_affinity_hint(irq_num, &q_vector->affinity_mask);
+		irq_update_affinity_hint(irq_num, &q_vector->affinity_mask);
 	}
 
 	err = ice_set_cpu_rx_rmap(vsi);
@@ -2625,7 +2625,7 @@  static int ice_vsi_req_irq_msix(struct ice_vsi *vsi, char *basename)
 		irq_num = vsi->q_vectors[vector]->irq.virq;
 		if (!IS_ENABLED(CONFIG_RFS_ACCEL))
 			irq_set_affinity_notifier(irq_num, NULL);
-		irq_set_affinity_hint(irq_num, NULL);
+		irq_update_affinity_hint(irq_num, NULL);
 		devm_free_irq(dev, irq_num, &vsi->q_vectors[vector]);
 	}
 	return err;