[PATCH net-next v8 0/6] net: napi: add CPU affinity to napi->config

[PATCH net-next v8 0/6] net: napi: add CPU affinity to napi->config

[Ahmed Zaki]

Drivers usually need to re-apply the user-set IRQ affinity to their IRQs
after reset. However, since there can be only one IRQ affinity notifier
for each IRQ, registering IRQ notifiers conflicts with the ARFS rmap
management in the core (which also registers separate IRQ affinity
notifiers).   

Move the IRQ affinity management to the napi struct. This way we can have
a unified IRQ notifier to re-apply the user-set affinity and also manage
the ARFS rmaps.

Ice does not always delete the NAPIS before releasing the IRQs. The first
patch makes sure the driver removes the IRQ number along with the queue
when the NAPIs are disabled. Without this, the next patches in this series
would free the IRQ before releasing the IRQ notifier (which generates
warnings).

The second patch moves the ARFS rmap management to CORE. Patch 3 adds the
IRQ affinity mask to napi_config and re-applies the mask after reset.
Patches 4-6 use the new API for bnxt, ice and idpf drivers.

Tested on bnxt, ice and idpf.

V8:
    - Add a new patch in "ice" that releases the IRQs and their notifiers
      when clearing the NAPI queues (pls read 3rd paragraph above).
    - Add a new NAPI flag "NAPI_STATE_HAS_NOTIFIER" that simplifies the
      code for IRQ notifier detection (Patch 2).
    - Move the IRQ notifier auto-removal to napi_delete() instead of
      napi_disable(). This is the reason for the new ice patch. (Jakub)
    - Add a WARN_ON_ONCE(!napi->config) in netif_napi_set_irq_locked().
      This would detect drivers that asked for irq_affinity_auto but did
      not use napi_add_config(). (Patch 3) (Joe)
    - Rename netif_enable_irq_affinity() to netif_set_affinity_auto()
      (Patch 3) (Jakub).
V7:
    - https://lore.kernel.org/netdev/20250204220622.156061-1-ahmed.zaki@intel.com/
    - P1: add documentation for netif_enable_cpu_rmap()
    - P1: move a couple of "if (rx_cpu_rmap_auto)" from patch 1 to patch 2
      where they are really needed.
    - P1: remove a defensive "if (!rmap)"
    - p1: In netif_disable_cpu_rmap(), remove the for loop that frees
          notifiers since this is already done in napi_disable_locked().
          Also rename it to netif_del_cpu_rmap().
    - P1 and P2: simplify the if conditions in netif_napi_set_irq_locked()
    - Other nits

V6:
    - https://lore.kernel.org/netdev/20250118003335.155379-1-ahmed.zaki@intel.com/
    - Modifications to have less #ifdef CONFIG_RF_ACCL guards
    - Remove rmap entry in napi_disable
    - Rebase on rc7 and use netif_napi_set_irq_locked()
    - Assume IRQ can be -1 and free resources if an old valid IRQ was
      associated with the napi. For this, I had to merge the first 2
      patches to use the new rmap API.

V5:
    - https://lore.kernel.org/netdev/20250113171042.158123-1-ahmed.zaki@intel.com/
    - Add kernel doc for new netdev flags (Simon).
    - Remove defensive (if !napi) check in napi_irq_cpu_rmap_add()
      (patch 2) since caller is already dereferencing the pointer (Simon).
    - Fix build error when CONFIG_ARFS_ACCEL is not defined (patch 3).

v4:
    - https://lore.kernel.org/netdev/20250109233107.17519-1-ahmed.zaki@intel.com/
    - Better introduction in the cover letter.
    - Fix Kernel build errors in ena_init_rx_cpu_rmap() (Patch 1)
    - Fix kernel test robot warnings reported by Dan Carpenter:
      https://lore.kernel.org/all/202501050625.nY1c97EX-lkp@intel.com/
    - Remove unrelated empty line in patch 4 (Kalesh Anakkur Purayil)
    - Fix a memleak (rmap was not freed) by calling cpu_rmap_put() in
      netif_napi_affinity_release() (patch 2).

v3:
    - https://lore.kernel.org/netdev/20250104004314.208259-1-ahmed.zaki@intel.com/
    - Assign one cpu per mask starting from local NUMA node (Shay Drori).
    - Keep the new ARFS and Affinity flags per nedev (Jakub).

v2:
    - https://lore.kernel.org/netdev/202412190454.nwvp3hU2-lkp@intel.com/T/
    - Also move the ARFS IRQ affinity management from drivers to core. Via
      netif_napi_set_irq(), drivers can ask the core to add the IRQ to the
      ARFS rmap (already allocated by the driver).

RFC -> v1:
    - https://lore.kernel.org/netdev/20241210002626.366878-1-ahmed.zaki@intel.com/
    - move static inline affinity functions to net/dev/core.c
    - add the new napi->irq_flags (patch 1)
    - add code changes to bnxt, mlx4 and ice.

Ahmed Zaki (6):
  ice: clear NAPI's IRQ numbers in ice_vsi_clear_napi_queues()
  net: move ARFS rmap management to core
  net: napi: add CPU affinity to napi_config
  bnxt: use napi's irq affinity
  ice: use napi's irq affinity
  idpf: use napi's irq affinity

 Documentation/networking/scaling.rst         |   6 +-
 drivers/net/ethernet/amazon/ena/ena_netdev.c |  43 +----
 drivers/net/ethernet/broadcom/bnxt/bnxt.c    |  54 +-----
 drivers/net/ethernet/broadcom/bnxt/bnxt.h    |   2 -
 drivers/net/ethernet/intel/ice/ice.h         |   3 -
 drivers/net/ethernet/intel/ice/ice_arfs.c    |  33 +---
 drivers/net/ethernet/intel/ice/ice_arfs.h    |   2 -
 drivers/net/ethernet/intel/ice/ice_base.c    |   7 +-
 drivers/net/ethernet/intel/ice/ice_lib.c     |  16 +-
 drivers/net/ethernet/intel/ice/ice_main.c    |  47 +----
 drivers/net/ethernet/intel/idpf/idpf_lib.c   |   1 +
 drivers/net/ethernet/intel/idpf/idpf_txrx.c  |  22 +--
 drivers/net/ethernet/intel/idpf/idpf_txrx.h  |   6 +-
 include/linux/cpu_rmap.h                     |   1 +
 include/linux/netdevice.h                    |  28 ++-
 lib/cpu_rmap.c                               |   2 +-
 net/core/dev.c                               | 172 ++++++++++++++++++-
 17 files changed, 233 insertions(+), 212 deletions(-)

-- 
2.43.0

[PATCH net-next v8 1/6] ice: clear NAPI's IRQ numbers in ice_vsi_clear_napi_queues()

[Ahmed Zaki]

We set the NAPI's IRQ number in ice_vsi_set_napi_queues(). Clear the
NAPI's IRQ in ice_vsi_clear_napi_queues().

Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_lib.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 16c419809849..b2467dc17681 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2766,11 +2766,18 @@ void ice_vsi_set_napi_queues(struct ice_vsi *vsi)
 void ice_vsi_clear_napi_queues(struct ice_vsi *vsi)
 {
 	struct net_device *netdev = vsi->netdev;
-	int q_idx;
+	int q_idx, v_idx;
 
 	if (!netdev)
 		return;
 
+	/* Clear the NAPI's interrupt number */
+	ice_for_each_q_vector(vsi, v_idx) {
+		struct ice_q_vector *q_vector = vsi->q_vectors[v_idx];
+
+		netif_napi_set_irq(&q_vector->napi, -1);
+	}
+
 	ice_for_each_txq(vsi, q_idx)
 		netif_queue_set_napi(netdev, q_idx, NETDEV_QUEUE_TYPE_TX, NULL);
 
-- 
2.43.0

[PATCH net-next v8 2/6] net: move ARFS rmap management to core

[Ahmed Zaki]

Add a new netdev flag "rx_cpu_rmap_auto". Drivers supporting ARFS should
set the flag via netif_enable_cpu_rmap() and core will allocate and manage
the ARFS rmap. Freeing the rmap is also done by core when the netdev is
freed.

For better IRQ affinity management, move the IRQ rmap notifier inside the
napi_struct. Consequently, add new notify.notify and notify.release
functions: netif_irq_cpu_rmap_notify() and netif_napi_affinity_release().

Acked-by: David Arinzon <darinzon@amazon.com>
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
---
 Documentation/networking/scaling.rst         |   6 +-
 drivers/net/ethernet/amazon/ena/ena_netdev.c |  43 +------
 drivers/net/ethernet/broadcom/bnxt/bnxt.c    |  29 +----
 drivers/net/ethernet/intel/ice/ice_arfs.c    |  33 +----
 drivers/net/ethernet/intel/ice/ice_arfs.h    |   2 -
 drivers/net/ethernet/intel/ice/ice_lib.c     |   1 -
 include/linux/cpu_rmap.h                     |   1 +
 include/linux/netdevice.h                    |  17 ++-
 lib/cpu_rmap.c                               |   2 +-
 net/core/dev.c                               | 125 +++++++++++++++++++
 10 files changed, 150 insertions(+), 109 deletions(-)

diff --git a/Documentation/networking/scaling.rst b/Documentation/networking/scaling.rst
index 4eb50bcb9d42..e5d4d3ecb980 100644
--- a/Documentation/networking/scaling.rst
+++ b/Documentation/networking/scaling.rst
@@ -427,8 +427,10 @@ rps_dev_flow_table. The stack consults a CPU to hardware queue map which
 is maintained by the NIC driver. This is an auto-generated reverse map of
 the IRQ affinity table shown by /proc/interrupts. Drivers can use
 functions in the cpu_rmap (“CPU affinity reverse map”) kernel library
-to populate the map. For each CPU, the corresponding queue in the map is
-set to be one whose processing CPU is closest in cache locality.
+to populate the map. Alternatively, drivers can delegate the cpu_rmap
+management to the Kernel by calling netif_enable_cpu_rmap(). For each CPU,
+the corresponding queue in the map is set to be one whose processing CPU is
+closest in cache locality.
 
 
 Accelerated RFS Configuration
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index c1295dfad0d0..6aab85a7c60a 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -5,9 +5,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#ifdef CONFIG_RFS_ACCEL
-#include <linux/cpu_rmap.h>
-#endif /* CONFIG_RFS_ACCEL */
 #include <linux/ethtool.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -162,30 +159,6 @@ int ena_xmit_common(struct ena_adapter *adapter,
 	return 0;
 }
 
-static int ena_init_rx_cpu_rmap(struct ena_adapter *adapter)
-{
-#ifdef CONFIG_RFS_ACCEL
-	u32 i;
-	int rc;
-
-	adapter->netdev->rx_cpu_rmap = alloc_irq_cpu_rmap(adapter->num_io_queues);
-	if (!adapter->netdev->rx_cpu_rmap)
-		return -ENOMEM;
-	for (i = 0; i < adapter->num_io_queues; i++) {
-		int irq_idx = ENA_IO_IRQ_IDX(i);
-
-		rc = irq_cpu_rmap_add(adapter->netdev->rx_cpu_rmap,
-				      pci_irq_vector(adapter->pdev, irq_idx));
-		if (rc) {
-			free_irq_cpu_rmap(adapter->netdev->rx_cpu_rmap);
-			adapter->netdev->rx_cpu_rmap = NULL;
-			return rc;
-		}
-	}
-#endif /* CONFIG_RFS_ACCEL */
-	return 0;
-}
-
 static void ena_init_io_rings_common(struct ena_adapter *adapter,
 				     struct ena_ring *ring, u16 qid)
 {
@@ -1596,7 +1569,7 @@ static int ena_enable_msix(struct ena_adapter *adapter)
 		adapter->num_io_queues = irq_cnt - ENA_ADMIN_MSIX_VEC;
 	}
 
-	if (ena_init_rx_cpu_rmap(adapter))
+	if (netif_enable_cpu_rmap(adapter->netdev, adapter->num_io_queues))
 		netif_warn(adapter, probe, adapter->netdev,
 			   "Failed to map IRQs to CPUs\n");
 
@@ -1742,13 +1715,6 @@ static void ena_free_io_irq(struct ena_adapter *adapter)
 	struct ena_irq *irq;
 	int i;
 
-#ifdef CONFIG_RFS_ACCEL
-	if (adapter->msix_vecs >= 1) {
-		free_irq_cpu_rmap(adapter->netdev->rx_cpu_rmap);
-		adapter->netdev->rx_cpu_rmap = NULL;
-	}
-#endif /* CONFIG_RFS_ACCEL */
-
 	for (i = ENA_IO_IRQ_FIRST_IDX; i < ENA_MAX_MSIX_VEC(io_queue_count); i++) {
 		irq = &adapter->irq_tbl[i];
 		irq_set_affinity_hint(irq->vector, NULL);
@@ -4131,13 +4097,6 @@ static void __ena_shutoff(struct pci_dev *pdev, bool shutdown)
 	ena_dev = adapter->ena_dev;
 	netdev = adapter->netdev;
 
-#ifdef CONFIG_RFS_ACCEL
-	if ((adapter->msix_vecs >= 1) && (netdev->rx_cpu_rmap)) {
-		free_irq_cpu_rmap(netdev->rx_cpu_rmap);
-		netdev->rx_cpu_rmap = NULL;
-	}
-
-#endif /* CONFIG_RFS_ACCEL */
 	/* Make sure timer and reset routine won't be called after
 	 * freeing device resources.
 	 */
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 7b8b5b39c7bb..b9b839cb942a 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -49,7 +49,6 @@
 #include <linux/cache.h>
 #include <linux/log2.h>
 #include <linux/bitmap.h>
-#include <linux/cpu_rmap.h>
 #include <linux/cpumask.h>
 #include <net/pkt_cls.h>
 #include <net/page_pool/helpers.h>
@@ -10886,10 +10885,8 @@ static int bnxt_set_real_num_queues(struct bnxt *bp)
 	if (rc)
 		return rc;
 
-#ifdef CONFIG_RFS_ACCEL
 	if (bp->flags & BNXT_FLAG_RFS)
-		dev->rx_cpu_rmap = alloc_irq_cpu_rmap(bp->rx_nr_rings);
-#endif
+		return netif_enable_cpu_rmap(dev, bp->rx_nr_rings);
 
 	return rc;
 }
@@ -11242,10 +11239,6 @@ static void bnxt_free_irq(struct bnxt *bp)
 	struct bnxt_irq *irq;
 	int i;
 
-#ifdef CONFIG_RFS_ACCEL
-	free_irq_cpu_rmap(bp->dev->rx_cpu_rmap);
-	bp->dev->rx_cpu_rmap = NULL;
-#endif
 	if (!bp->irq_tbl || !bp->bnapi)
 		return;
 
@@ -11268,11 +11261,8 @@ static void bnxt_free_irq(struct bnxt *bp)
 
 static int bnxt_request_irq(struct bnxt *bp)
 {
-	int i, j, rc = 0;
+	int i, rc = 0;
 	unsigned long flags = 0;
-#ifdef CONFIG_RFS_ACCEL
-	struct cpu_rmap *rmap;
-#endif
 
 	rc = bnxt_setup_int_mode(bp);
 	if (rc) {
@@ -11280,22 +11270,11 @@ static int bnxt_request_irq(struct bnxt *bp)
 			   rc);
 		return rc;
 	}
-#ifdef CONFIG_RFS_ACCEL
-	rmap = bp->dev->rx_cpu_rmap;
-#endif
-	for (i = 0, j = 0; i < bp->cp_nr_rings; i++) {
+
+	for (i = 0; i < bp->cp_nr_rings; i++) {
 		int map_idx = bnxt_cp_num_to_irq_num(bp, i);
 		struct bnxt_irq *irq = &bp->irq_tbl[map_idx];
 
-#ifdef CONFIG_RFS_ACCEL
-		if (rmap && bp->bnapi[i]->rx_ring) {
-			rc = irq_cpu_rmap_add(rmap, irq->vector);
-			if (rc)
-				netdev_warn(bp->dev, "failed adding irq rmap for ring %d\n",
-					    j);
-			j++;
-		}
-#endif
 		rc = request_irq(irq->vector, irq->handler, flags, irq->name,
 				 bp->bnapi[i]);
 		if (rc)
diff --git a/drivers/net/ethernet/intel/ice/ice_arfs.c b/drivers/net/ethernet/intel/ice/ice_arfs.c
index 7cee365cc7d1..171cdec741c2 100644
--- a/drivers/net/ethernet/intel/ice/ice_arfs.c
+++ b/drivers/net/ethernet/intel/ice/ice_arfs.c
@@ -570,25 +570,6 @@ void ice_clear_arfs(struct ice_vsi *vsi)
 	vsi->arfs_fltr_cntrs = NULL;
 }
 
-/**
- * ice_free_cpu_rx_rmap - free setup CPU reverse map
- * @vsi: the VSI to be forwarded to
- */
-void ice_free_cpu_rx_rmap(struct ice_vsi *vsi)
-{
-	struct net_device *netdev;
-
-	if (!vsi || vsi->type != ICE_VSI_PF)
-		return;
-
-	netdev = vsi->netdev;
-	if (!netdev || !netdev->rx_cpu_rmap)
-		return;
-
-	free_irq_cpu_rmap(netdev->rx_cpu_rmap);
-	netdev->rx_cpu_rmap = NULL;
-}
-
 /**
  * ice_set_cpu_rx_rmap - setup CPU reverse map for each queue
  * @vsi: the VSI to be forwarded to
@@ -597,7 +578,6 @@ int ice_set_cpu_rx_rmap(struct ice_vsi *vsi)
 {
 	struct net_device *netdev;
 	struct ice_pf *pf;
-	int i;
 
 	if (!vsi || vsi->type != ICE_VSI_PF)
 		return 0;
@@ -610,18 +590,7 @@ int ice_set_cpu_rx_rmap(struct ice_vsi *vsi)
 	netdev_dbg(netdev, "Setup CPU RMAP: vsi type 0x%x, ifname %s, q_vectors %d\n",
 		   vsi->type, netdev->name, vsi->num_q_vectors);
 
-	netdev->rx_cpu_rmap = alloc_irq_cpu_rmap(vsi->num_q_vectors);
-	if (unlikely(!netdev->rx_cpu_rmap))
-		return -EINVAL;
-
-	ice_for_each_q_vector(vsi, i)
-		if (irq_cpu_rmap_add(netdev->rx_cpu_rmap,
-				     vsi->q_vectors[i]->irq.virq)) {
-			ice_free_cpu_rx_rmap(vsi);
-			return -EINVAL;
-		}
-
-	return 0;
+	return netif_enable_cpu_rmap(netdev, vsi->num_q_vectors);
 }
 
 /**
diff --git a/drivers/net/ethernet/intel/ice/ice_arfs.h b/drivers/net/ethernet/intel/ice/ice_arfs.h
index 9669ad9bf7b5..9706293128c3 100644
--- a/drivers/net/ethernet/intel/ice/ice_arfs.h
+++ b/drivers/net/ethernet/intel/ice/ice_arfs.h
@@ -45,7 +45,6 @@ int
 ice_rx_flow_steer(struct net_device *netdev, const struct sk_buff *skb,
 		  u16 rxq_idx, u32 flow_id);
 void ice_clear_arfs(struct ice_vsi *vsi);
-void ice_free_cpu_rx_rmap(struct ice_vsi *vsi);
 void ice_init_arfs(struct ice_vsi *vsi);
 void ice_sync_arfs_fltrs(struct ice_pf *pf);
 int ice_set_cpu_rx_rmap(struct ice_vsi *vsi);
@@ -56,7 +55,6 @@ ice_is_arfs_using_perfect_flow(struct ice_hw *hw,
 			       enum ice_fltr_ptype flow_type);
 #else
 static inline void ice_clear_arfs(struct ice_vsi *vsi) { }
-static inline void ice_free_cpu_rx_rmap(struct ice_vsi *vsi) { }
 static inline void ice_init_arfs(struct ice_vsi *vsi) { }
 static inline void ice_sync_arfs_fltrs(struct ice_pf *pf) { }
 static inline void ice_remove_arfs(struct ice_pf *pf) { }
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index b2467dc17681..916b072ab718 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2593,7 +2593,6 @@ void ice_vsi_free_irq(struct ice_vsi *vsi)
 		return;
 
 	vsi->irqs_ready = false;
-	ice_free_cpu_rx_rmap(vsi);
 
 	ice_for_each_q_vector(vsi, i) {
 		int irq_num;
diff --git a/include/linux/cpu_rmap.h b/include/linux/cpu_rmap.h
index 20b5729903d7..2fd7ba75362a 100644
--- a/include/linux/cpu_rmap.h
+++ b/include/linux/cpu_rmap.h
@@ -32,6 +32,7 @@ struct cpu_rmap {
 #define CPU_RMAP_DIST_INF 0xffff
 
 extern struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags);
+extern void cpu_rmap_get(struct cpu_rmap *rmap);
 extern int cpu_rmap_put(struct cpu_rmap *rmap);
 
 extern int cpu_rmap_add(struct cpu_rmap *rmap, void *obj);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5429581f2299..9344d9b632d4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -394,6 +394,10 @@ struct napi_struct {
 	struct list_head	dev_list;
 	struct hlist_node	napi_hash_node;
 	int			irq;
+#ifdef CONFIG_RFS_ACCEL
+	struct irq_affinity_notify notify;
+	int			napi_rmap_idx;
+#endif
 	int			index;
 	struct napi_config	*config;
 };
@@ -409,6 +413,7 @@ enum {
 	NAPI_STATE_PREFER_BUSY_POLL,	/* prefer busy-polling over softirq processing*/
 	NAPI_STATE_THREADED,		/* The poll is performed inside its own thread*/
 	NAPI_STATE_SCHED_THREADED,	/* Napi is currently scheduled in threaded mode */
+	NAPI_STATE_HAS_NOTIFIER,	/* Napi has an IRQ notifier */
 };
 
 enum {
@@ -422,6 +427,7 @@ enum {
 	NAPIF_STATE_PREFER_BUSY_POLL	= BIT(NAPI_STATE_PREFER_BUSY_POLL),
 	NAPIF_STATE_THREADED		= BIT(NAPI_STATE_THREADED),
 	NAPIF_STATE_SCHED_THREADED	= BIT(NAPI_STATE_SCHED_THREADED),
+	NAPIF_STATE_HAS_NOTIFIER	= BIT(NAPI_STATE_HAS_NOTIFIER),
 };
 
 enum gro_result {
@@ -1989,6 +1995,9 @@ enum netdev_reg_state {
  *
  *	@threaded:	napi threaded mode is enabled
  *
+ *	@rx_cpu_rmap_auto: driver wants the core to manage the ARFS rmap.
+ *	                   Set by calling netif_enable_cpu_rmap().
+ *
  *	@see_all_hwtstamp_requests: device wants to see calls to
  *			ndo_hwtstamp_set() for all timestamp requests
  *			regardless of source, even if those aren't
@@ -2396,6 +2405,7 @@ struct net_device {
 	struct lock_class_key	*qdisc_tx_busylock;
 	bool			proto_down;
 	bool			threaded;
+	bool			rx_cpu_rmap_auto;
 
 	/* priv_flags_slow, ungrouped to save space */
 	unsigned long		see_all_hwtstamp_requests:1;
@@ -2718,10 +2728,7 @@ static inline void netdev_assert_locked_or_invisible(struct net_device *dev)
 		netdev_assert_locked(dev);
 }
 
-static inline void netif_napi_set_irq_locked(struct napi_struct *napi, int irq)
-{
-	napi->irq = irq;
-}
+void netif_napi_set_irq_locked(struct napi_struct *napi, int irq);
 
 static inline void netif_napi_set_irq(struct napi_struct *napi, int irq)
 {
@@ -2859,6 +2866,8 @@ static inline void netif_napi_del(struct napi_struct *napi)
 	synchronize_net();
 }
 
+int netif_enable_cpu_rmap(struct net_device *dev, unsigned int num_irqs);
+
 struct packet_type {
 	__be16			type;	/* This is really htons(ether_type). */
 	bool			ignore_outgoing;
diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c
index 4c348670da31..f03d9be3f06b 100644
--- a/lib/cpu_rmap.c
+++ b/lib/cpu_rmap.c
@@ -73,7 +73,7 @@ static void cpu_rmap_release(struct kref *ref)
  * cpu_rmap_get - internal helper to get new ref on a cpu_rmap
  * @rmap: reverse-map allocated with alloc_cpu_rmap()
  */
-static inline void cpu_rmap_get(struct cpu_rmap *rmap)
+void cpu_rmap_get(struct cpu_rmap *rmap)
 {
 	kref_get(&rmap->refcount);
 }
diff --git a/net/core/dev.c b/net/core/dev.c
index d5ab9a4b318e..209296cef3cd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6871,6 +6871,126 @@ void netif_queue_set_napi(struct net_device *dev, unsigned int queue_index,
 }
 EXPORT_SYMBOL(netif_queue_set_napi);
 
+#ifdef CONFIG_RFS_ACCEL
+static void
+netif_irq_cpu_rmap_notify(struct irq_affinity_notify *notify,
+			  const cpumask_t *mask)
+{
+	struct napi_struct *napi =
+		container_of(notify, struct napi_struct, notify);
+	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
+	int err;
+
+	err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
+	if (err)
+		netdev_warn(napi->dev, "RMAP update failed (%d)\n",
+			    err);
+}
+
+static void netif_napi_affinity_release(struct kref *ref)
+{
+	struct napi_struct *napi =
+		container_of(ref, struct napi_struct, notify.kref);
+	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
+
+	rmap->obj[napi->napi_rmap_idx] = NULL;
+	napi->napi_rmap_idx = -1;
+	cpu_rmap_put(rmap);
+}
+
+static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
+{
+	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
+	int rc;
+
+	napi->notify.notify = netif_irq_cpu_rmap_notify;
+	napi->notify.release = netif_napi_affinity_release;
+	cpu_rmap_get(rmap);
+	rc = cpu_rmap_add(rmap, napi);
+	if (rc < 0)
+		goto err_add;
+
+	napi->napi_rmap_idx = rc;
+	rc = irq_set_affinity_notifier(irq, &napi->notify);
+	if (rc)
+		goto err_set;
+
+	set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);
+	return 0;
+
+err_set:
+	rmap->obj[napi->napi_rmap_idx] = NULL;
+	napi->napi_rmap_idx = -1;
+err_add:
+	cpu_rmap_put(rmap);
+	return rc;
+}
+
+int netif_enable_cpu_rmap(struct net_device *dev, unsigned int num_irqs)
+{
+	if (dev->rx_cpu_rmap_auto)
+		return 0;
+
+	dev->rx_cpu_rmap = alloc_irq_cpu_rmap(num_irqs);
+	if (!dev->rx_cpu_rmap)
+		return -ENOMEM;
+
+	dev->rx_cpu_rmap_auto = true;
+	return 0;
+}
+EXPORT_SYMBOL(netif_enable_cpu_rmap);
+
+static void netif_del_cpu_rmap(struct net_device *dev)
+{
+	struct cpu_rmap *rmap = dev->rx_cpu_rmap;
+
+	if (!dev->rx_cpu_rmap_auto)
+		return;
+
+	/* Free the rmap */
+	cpu_rmap_put(rmap);
+	dev->rx_cpu_rmap = NULL;
+	dev->rx_cpu_rmap_auto = false;
+}
+
+#else
+static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
+{
+	return 0;
+}
+
+int netif_enable_cpu_rmap(struct net_device *dev, unsigned int num_irqs)
+{
+	return 0;
+}
+EXPORT_SYMBOL(netif_enable_cpu_rmap);
+
+static void netif_del_cpu_rmap(struct net_device *dev)
+{
+}
+#endif
+
+void netif_napi_set_irq_locked(struct napi_struct *napi, int irq)
+{
+	int rc;
+
+	if (napi->irq == irq)
+		return;
+
+	/* Remove existing rmap entries */
+	if (test_and_clear_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state))
+		irq_set_affinity_notifier(napi->irq, NULL);
+
+	napi->irq = irq;
+	if (irq < 0)
+		return;
+
+	rc = napi_irq_cpu_rmap_add(napi, irq);
+	if (rc)
+		netdev_warn(napi->dev, "Unable to update aRFS map (%d)\n", rc);
+}
+EXPORT_SYMBOL(netif_napi_set_irq_locked);
+
 static void napi_restore_config(struct napi_struct *n)
 {
 	n->defer_hard_irqs = n->config->defer_hard_irqs;
@@ -7079,6 +7199,9 @@ void __netif_napi_del_locked(struct napi_struct *napi)
 	/* Make sure NAPI is disabled (or was never enabled). */
 	WARN_ON(!test_bit(NAPI_STATE_SCHED, &napi->state));
 
+	if (test_and_clear_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state))
+		irq_set_affinity_notifier(napi->irq, NULL);
+
 	if (napi->config) {
 		napi->index = -1;
 		napi->config = NULL;
@@ -11632,6 +11755,8 @@ void free_netdev(struct net_device *dev)
 
 	netdev_napi_exit(dev);
 
+	netif_del_cpu_rmap(dev);
+
 	ref_tracker_dir_exit(&dev->refcnt_tracker);
 #ifdef CONFIG_PCPU_DEV_REFCNT
 	free_percpu(dev->pcpu_refcnt);
-- 
2.43.0

[PATCH net-next v8 3/6] net: napi: add CPU affinity to napi_config

[Ahmed Zaki]

A common task for most drivers is to remember the user-set CPU affinity
to its IRQs. On each netdev reset, the driver should re-assign the
user's settings to the IRQs.

Add CPU affinity mask to napi_config. To delegate the CPU affinity
management to the core, drivers must:
 1 - set the new netdev flag "irq_affinity_auto":
                                       netif_enable_irq_affinity(netdev)
 2 - create the napi with persistent config:
                                       netif_napi_add_config()
 3 - bind an IRQ to the napi instance: netif_napi_set_irq()

the core will then make sure to use re-assign affinity to the napi's
IRQ.

The default IRQ mask is set to one cpu starting from the closest NUMA.

Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
---
 include/linux/netdevice.h | 15 ++++++--
 net/core/dev.c            | 73 +++++++++++++++++++++++++++++++--------
 2 files changed, 72 insertions(+), 16 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9344d9b632d4..63fb392558b3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -352,6 +352,7 @@ struct napi_config {
 	u64 gro_flush_timeout;
 	u64 irq_suspend_timeout;
 	u32 defer_hard_irqs;
+	cpumask_t affinity_mask;
 	unsigned int napi_id;
 };
 
@@ -394,10 +395,8 @@ struct napi_struct {
 	struct list_head	dev_list;
 	struct hlist_node	napi_hash_node;
 	int			irq;
-#ifdef CONFIG_RFS_ACCEL
 	struct irq_affinity_notify notify;
 	int			napi_rmap_idx;
-#endif
 	int			index;
 	struct napi_config	*config;
 };
@@ -1995,6 +1994,12 @@ enum netdev_reg_state {
  *
  *	@threaded:	napi threaded mode is enabled
  *
+ *	@irq_affinity_auto: driver wants the core to store and re-assign the IRQ
+ *			    affinity. Set by netif_enable_irq_affinity(), then
+ *			    the driver must create a persistent napi by
+ *			    netif_napi_add_config() and finally bind the napi to
+ *			    IRQ (via netif_napi_set_irq()).
+ *
  *	@rx_cpu_rmap_auto: driver wants the core to manage the ARFS rmap.
  *	                   Set by calling netif_enable_cpu_rmap().
  *
@@ -2405,6 +2410,7 @@ struct net_device {
 	struct lock_class_key	*qdisc_tx_busylock;
 	bool			proto_down;
 	bool			threaded;
+	bool			irq_affinity_auto;
 	bool			rx_cpu_rmap_auto;
 
 	/* priv_flags_slow, ungrouped to save space */
@@ -2665,6 +2671,11 @@ static inline void netdev_set_ml_priv(struct net_device *dev,
 	dev->ml_priv_type = type;
 }
 
+static inline void netif_set_affinity_auto(struct net_device *dev)
+{
+	dev->irq_affinity_auto = true;
+}
+
 /*
  * Net namespace inlines
  */
diff --git a/net/core/dev.c b/net/core/dev.c
index 209296cef3cd..d2c942bbd5e6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6871,28 +6871,39 @@ void netif_queue_set_napi(struct net_device *dev, unsigned int queue_index,
 }
 EXPORT_SYMBOL(netif_queue_set_napi);
 
-#ifdef CONFIG_RFS_ACCEL
 static void
-netif_irq_cpu_rmap_notify(struct irq_affinity_notify *notify,
-			  const cpumask_t *mask)
+netif_napi_irq_notify(struct irq_affinity_notify *notify,
+		      const cpumask_t *mask)
 {
 	struct napi_struct *napi =
 		container_of(notify, struct napi_struct, notify);
+#ifdef CONFIG_RFS_ACCEL
 	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
 	int err;
+#endif
 
-	err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
-	if (err)
-		netdev_warn(napi->dev, "RMAP update failed (%d)\n",
-			    err);
+	if (napi->config && napi->dev->irq_affinity_auto)
+		cpumask_copy(&napi->config->affinity_mask, mask);
+
+#ifdef CONFIG_RFS_ACCEL
+	if (napi->dev->rx_cpu_rmap_auto) {
+		err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
+		if (err)
+			netdev_warn(napi->dev, "RMAP update failed (%d)\n",
+				    err);
+	}
+#endif
 }
 
+#ifdef CONFIG_RFS_ACCEL
 static void netif_napi_affinity_release(struct kref *ref)
 {
 	struct napi_struct *napi =
 		container_of(ref, struct napi_struct, notify.kref);
 	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
 
+	if (!napi->dev->rx_cpu_rmap_auto)
+		return;
 	rmap->obj[napi->napi_rmap_idx] = NULL;
 	napi->napi_rmap_idx = -1;
 	cpu_rmap_put(rmap);
@@ -6903,7 +6914,7 @@ static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
 	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
 	int rc;
 
-	napi->notify.notify = netif_irq_cpu_rmap_notify;
+	napi->notify.notify = netif_napi_irq_notify;
 	napi->notify.release = netif_napi_affinity_release;
 	cpu_rmap_get(rmap);
 	rc = cpu_rmap_add(rmap, napi);
@@ -6915,7 +6926,6 @@ static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
 	if (rc)
 		goto err_set;
 
-	set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);
 	return 0;
 
 err_set:
@@ -6954,6 +6964,10 @@ static void netif_del_cpu_rmap(struct net_device *dev)
 }
 
 #else
+static void netif_napi_affinity_release(struct kref *ref)
+{
+}
+
 static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
 {
 	return 0;
@@ -6977,7 +6991,7 @@ void netif_napi_set_irq_locked(struct napi_struct *napi, int irq)
 	if (napi->irq == irq)
 		return;
 
-	/* Remove existing rmap entries */
+	/* Remove existing resources */
 	if (test_and_clear_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state))
 		irq_set_affinity_notifier(napi->irq, NULL);
 
@@ -6985,9 +6999,30 @@ void netif_napi_set_irq_locked(struct napi_struct *napi, int irq)
 	if (irq < 0)
 		return;
 
-	rc = napi_irq_cpu_rmap_add(napi, irq);
-	if (rc)
-		netdev_warn(napi->dev, "Unable to update aRFS map (%d)\n", rc);
+	if (napi->dev->rx_cpu_rmap_auto) {
+		rc = napi_irq_cpu_rmap_add(napi, irq);
+		if (rc) {
+			netdev_warn(napi->dev, "Unable to update ARFS map (%d)\n",
+				    rc);
+			return;
+		}
+		set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);
+
+	} else if (napi->dev->irq_affinity_auto) {
+		if (WARN_ON_ONCE(!napi->config))
+			return;
+
+		napi->notify.notify = netif_napi_irq_notify;
+		napi->notify.release = netif_napi_affinity_release;
+
+		rc = irq_set_affinity_notifier(irq, &napi->notify);
+		if (rc) {
+			netdev_warn(napi->dev, "Unable to set IRQ notifier (%d)\n",
+				    rc);
+			return;
+		}
+		set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);
+	}
 }
 EXPORT_SYMBOL(netif_napi_set_irq_locked);
 
@@ -6996,6 +7031,11 @@ static void napi_restore_config(struct napi_struct *n)
 	n->defer_hard_irqs = n->config->defer_hard_irqs;
 	n->gro_flush_timeout = n->config->gro_flush_timeout;
 	n->irq_suspend_timeout = n->config->irq_suspend_timeout;
+
+	if (n->dev->irq_affinity_auto &&
+	    test_bit(NAPI_STATE_HAS_NOTIFIER, &n->state))
+		irq_set_affinity(n->irq, &n->config->affinity_mask);
+
 	/* a NAPI ID might be stored in the config, if so use it. if not, use
 	 * napi_hash_add to generate one for us.
 	 */
@@ -11575,9 +11615,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 		void (*setup)(struct net_device *),
 		unsigned int txqs, unsigned int rxqs)
 {
+	unsigned int maxqs, i, numa;
 	struct net_device *dev;
 	size_t napi_config_sz;
-	unsigned int maxqs;
 
 	BUG_ON(strlen(name) >= sizeof(dev->name));
 
@@ -11679,6 +11719,11 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	if (!dev->napi_config)
 		goto free_all;
 
+	numa = dev_to_node(&dev->dev);
+	for (i = 0; i < maxqs; i++)
+		cpumask_set_cpu(cpumask_local_spread(i, numa),
+				&dev->napi_config[i].affinity_mask);
+
 	strscpy(dev->name, name);
 	dev->name_assign_type = name_assign_type;
 	dev->group = INIT_NETDEV_GROUP;
-- 
2.43.0

[PATCH net-next v8 4/6] bnxt: use napi's irq affinity

[Ahmed Zaki]

Delete the driver CPU affinity info and use the core's napi config
instead.

Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 25 +++--------------------
 drivers/net/ethernet/broadcom/bnxt/bnxt.h |  2 --
 2 files changed, 3 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index b9b839cb942a..8b231bbc0709 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11246,14 +11246,8 @@ static void bnxt_free_irq(struct bnxt *bp)
 		int map_idx = bnxt_cp_num_to_irq_num(bp, i);
 
 		irq = &bp->irq_tbl[map_idx];
-		if (irq->requested) {
-			if (irq->have_cpumask) {
-				irq_update_affinity_hint(irq->vector, NULL);
-				free_cpumask_var(irq->cpu_mask);
-				irq->have_cpumask = 0;
-			}
+		if (irq->requested)
 			free_irq(irq->vector, bp->bnapi[i]);
-		}
 
 		irq->requested = 0;
 	}
@@ -11282,21 +11276,6 @@ static int bnxt_request_irq(struct bnxt *bp)
 
 		netif_napi_set_irq(&bp->bnapi[i]->napi, irq->vector);
 		irq->requested = 1;
-
-		if (zalloc_cpumask_var(&irq->cpu_mask, GFP_KERNEL)) {
-			int numa_node = dev_to_node(&bp->pdev->dev);
-
-			irq->have_cpumask = 1;
-			cpumask_set_cpu(cpumask_local_spread(i, numa_node),
-					irq->cpu_mask);
-			rc = irq_update_affinity_hint(irq->vector, irq->cpu_mask);
-			if (rc) {
-				netdev_warn(bp->dev,
-					    "Update affinity hint failed, IRQ = %d\n",
-					    irq->vector);
-				break;
-			}
-		}
 	}
 	return rc;
 }
@@ -16225,6 +16204,8 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	dev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
 			    NETDEV_XDP_ACT_RX_SG;
 
+	netif_set_affinity_auto(dev);
+
 #ifdef CONFIG_BNXT_SRIOV
 	init_waitqueue_head(&bp->sriov_cfg_wait);
 #endif
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 2373f423a523..9e6984458b46 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -1231,9 +1231,7 @@ struct bnxt_irq {
 	irq_handler_t	handler;
 	unsigned int	vector;
 	u8		requested:1;
-	u8		have_cpumask:1;
 	char		name[IFNAMSIZ + BNXT_IRQ_NAME_EXTRA];
-	cpumask_var_t	cpu_mask;
 };
 
 #define HWRM_RING_ALLOC_TX	0x1
-- 
2.43.0

[PATCH net-next v8 5/6] ice: use napi's irq affinity

[Ahmed Zaki]

Delete the driver CPU affinity info and use the core's napi config
instead.

Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
---
 drivers/net/ethernet/intel/ice/ice.h      |  3 --
 drivers/net/ethernet/intel/ice/ice_base.c |  7 +---
 drivers/net/ethernet/intel/ice/ice_lib.c  |  6 ---
 drivers/net/ethernet/intel/ice/ice_main.c | 47 ++---------------------
 4 files changed, 5 insertions(+), 58 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 2a6de2115193..9a5f8919d1a4 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -475,9 +475,6 @@ struct ice_q_vector {
 	struct ice_ring_container rx;
 	struct ice_ring_container tx;
 
-	cpumask_t affinity_mask;
-	struct irq_affinity_notify affinity_notify;
-
 	struct ice_channel *ch;
 
 	char name[ICE_INT_NAME_STR_LEN];
diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
index 0e862f20427a..5901795f3b62 100644
--- a/drivers/net/ethernet/intel/ice/ice_base.c
+++ b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -147,10 +147,6 @@ static int ice_vsi_alloc_q_vector(struct ice_vsi *vsi, u16 v_idx)
 	q_vector->reg_idx = q_vector->irq.index;
 	q_vector->vf_reg_idx = q_vector->irq.index;
 
-	/* only set affinity_mask if the CPU is online */
-	if (cpu_online(v_idx))
-		cpumask_set_cpu(v_idx, &q_vector->affinity_mask);
-
 	/* This will not be called in the driver load path because the netdev
 	 * will not be created yet. All other cases with register the NAPI
 	 * handler here (i.e. resume, reset/rebuild, etc.)
@@ -276,7 +272,8 @@ static void ice_cfg_xps_tx_ring(struct ice_tx_ring *ring)
 	if (test_and_set_bit(ICE_TX_XPS_INIT_DONE, ring->xps_state))
 		return;
 
-	netif_set_xps_queue(ring->netdev, &ring->q_vector->affinity_mask,
+	netif_set_xps_queue(ring->netdev,
+			    &ring->q_vector->napi.config->affinity_mask,
 			    ring->q_index);
 }
 
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 916b072ab718..46a2762dd083 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2605,12 +2605,6 @@ void ice_vsi_free_irq(struct ice_vsi *vsi)
 		      vsi->q_vectors[i]->num_ring_rx))
 			continue;
 
-		/* clear the affinity notifier in the IRQ descriptor */
-		if (!IS_ENABLED(CONFIG_RFS_ACCEL))
-			irq_set_affinity_notifier(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 d7037de29545..094403f2bf55 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2527,34 +2527,6 @@ int ice_schedule_reset(struct ice_pf *pf, enum ice_reset_req reset)
 	return 0;
 }
 
-/**
- * ice_irq_affinity_notify - Callback for affinity changes
- * @notify: context as to what irq was changed
- * @mask: the new affinity mask
- *
- * This is a callback function used by the irq_set_affinity_notifier function
- * so that we may register to receive changes to the irq affinity masks.
- */
-static void
-ice_irq_affinity_notify(struct irq_affinity_notify *notify,
-			const cpumask_t *mask)
-{
-	struct ice_q_vector *q_vector =
-		container_of(notify, struct ice_q_vector, affinity_notify);
-
-	cpumask_copy(&q_vector->affinity_mask, mask);
-}
-
-/**
- * ice_irq_affinity_release - Callback for affinity notifier release
- * @ref: internal core kernel usage
- *
- * This is a callback function used by the irq_set_affinity_notifier function
- * to inform the current notification subscriber that they will no longer
- * receive notifications.
- */
-static void ice_irq_affinity_release(struct kref __always_unused *ref) {}
-
 /**
  * ice_vsi_ena_irq - Enable IRQ for the given VSI
  * @vsi: the VSI being configured
@@ -2618,19 +2590,6 @@ static int ice_vsi_req_irq_msix(struct ice_vsi *vsi, char *basename)
 				   err);
 			goto free_q_irqs;
 		}
-
-		/* register for affinity change notifications */
-		if (!IS_ENABLED(CONFIG_RFS_ACCEL)) {
-			struct irq_affinity_notify *affinity_notify;
-
-			affinity_notify = &q_vector->affinity_notify;
-			affinity_notify->notify = ice_irq_affinity_notify;
-			affinity_notify->release = ice_irq_affinity_release;
-			irq_set_affinity_notifier(irq_num, affinity_notify);
-		}
-
-		/* assign the mask for this irq */
-		irq_update_affinity_hint(irq_num, &q_vector->affinity_mask);
 	}
 
 	err = ice_set_cpu_rx_rmap(vsi);
@@ -2646,9 +2605,6 @@ static int ice_vsi_req_irq_msix(struct ice_vsi *vsi, char *basename)
 free_q_irqs:
 	while (vector--) {
 		irq_num = vsi->q_vectors[vector]->irq.virq;
-		if (!IS_ENABLED(CONFIG_RFS_ACCEL))
-			irq_set_affinity_notifier(irq_num, NULL);
-		irq_update_affinity_hint(irq_num, NULL);
 		devm_free_irq(dev, irq_num, &vsi->q_vectors[vector]);
 	}
 	return err;
@@ -3689,6 +3645,9 @@ void ice_set_netdev_features(struct net_device *netdev)
 	 */
 	netdev->hw_features |= NETIF_F_RXFCS;
 
+	/* Allow core to manage IRQs affinity */
+	netif_set_affinity_auto(netdev);
+
 	netif_set_tso_max_size(netdev, ICE_MAX_TSO_SIZE);
 }
 
-- 
2.43.0

[PATCH net-next v8 6/6] idpf: use napi's irq affinity

[Ahmed Zaki]

Delete the driver CPU affinity info and use the core's napi config
instead.

Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
---
 drivers/net/ethernet/intel/idpf/idpf_lib.c  |  1 +
 drivers/net/ethernet/intel/idpf/idpf_txrx.c | 22 +++++++--------------
 drivers/net/ethernet/intel/idpf/idpf_txrx.h |  6 ++----
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/intel/idpf/idpf_lib.c b/drivers/net/ethernet/intel/idpf/idpf_lib.c
index b4fbb99bfad2..078f71733d1d 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_lib.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_lib.c
@@ -814,6 +814,7 @@ static int idpf_cfg_netdev(struct idpf_vport *vport)
 	netdev->hw_features |= dflt_features | offloads;
 	netdev->hw_enc_features |= dflt_features | offloads;
 	idpf_set_ethtool_ops(netdev);
+	netif_set_affinity_auto(netdev);
 	SET_NETDEV_DEV(netdev, &adapter->pdev->dev);
 
 	/* carrier off on init to avoid Tx hangs */
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
index 2fa9c36e33c9..f6b5b45a061c 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
@@ -3554,8 +3554,6 @@ void idpf_vport_intr_rel(struct idpf_vport *vport)
 		q_vector->tx = NULL;
 		kfree(q_vector->rx);
 		q_vector->rx = NULL;
-
-		free_cpumask_var(q_vector->affinity_mask);
 	}
 
 	kfree(vport->q_vectors);
@@ -3582,8 +3580,6 @@ static void idpf_vport_intr_rel_irq(struct idpf_vport *vport)
 		vidx = vport->q_vector_idxs[vector];
 		irq_num = adapter->msix_entries[vidx].vector;
 
-		/* clear the affinity_mask in the IRQ descriptor */
-		irq_set_affinity_hint(irq_num, NULL);
 		kfree(free_irq(irq_num, q_vector));
 	}
 }
@@ -3771,8 +3767,6 @@ static int idpf_vport_intr_req_irq(struct idpf_vport *vport)
 				   "Request_irq failed, error: %d\n", err);
 			goto free_q_irqs;
 		}
-		/* assign the mask for this irq */
-		irq_set_affinity_hint(irq_num, q_vector->affinity_mask);
 	}
 
 	return 0;
@@ -4184,7 +4178,8 @@ static int idpf_vport_intr_init_vec_idx(struct idpf_vport *vport)
 static void idpf_vport_intr_napi_add_all(struct idpf_vport *vport)
 {
 	int (*napi_poll)(struct napi_struct *napi, int budget);
-	u16 v_idx;
+	u16 v_idx, qv_idx;
+	int irq_num;
 
 	if (idpf_is_queue_model_split(vport->txq_model))
 		napi_poll = idpf_vport_splitq_napi_poll;
@@ -4193,12 +4188,12 @@ static void idpf_vport_intr_napi_add_all(struct idpf_vport *vport)
 
 	for (v_idx = 0; v_idx < vport->num_q_vectors; v_idx++) {
 		struct idpf_q_vector *q_vector = &vport->q_vectors[v_idx];
+		qv_idx = vport->q_vector_idxs[v_idx];
+		irq_num = vport->adapter->msix_entries[qv_idx].vector;
 
-		netif_napi_add(vport->netdev, &q_vector->napi, napi_poll);
-
-		/* only set affinity_mask if the CPU is online */
-		if (cpu_online(v_idx))
-			cpumask_set_cpu(v_idx, q_vector->affinity_mask);
+		netif_napi_add_config(vport->netdev, &q_vector->napi,
+				      napi_poll, v_idx);
+		netif_napi_set_irq(&q_vector->napi, irq_num);
 	}
 }
 
@@ -4242,9 +4237,6 @@ int idpf_vport_intr_alloc(struct idpf_vport *vport)
 		q_vector->rx_intr_mode = IDPF_ITR_DYNAMIC;
 		q_vector->rx_itr_idx = VIRTCHNL2_ITR_IDX_0;
 
-		if (!zalloc_cpumask_var(&q_vector->affinity_mask, GFP_KERNEL))
-			goto error;
-
 		q_vector->tx = kcalloc(txqs_per_vector, sizeof(*q_vector->tx),
 				       GFP_KERNEL);
 		if (!q_vector->tx)
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.h b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
index 0f71a6f5557b..13251f63c7c3 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.h
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
@@ -401,7 +401,6 @@ struct idpf_intr_reg {
  * @rx_intr_mode: Dynamic ITR or not
  * @rx_itr_idx: RX ITR index
  * @v_idx: Vector index
- * @affinity_mask: CPU affinity mask
  */
 struct idpf_q_vector {
 	__cacheline_group_begin_aligned(read_mostly);
@@ -438,13 +437,12 @@ struct idpf_q_vector {
 	__cacheline_group_begin_aligned(cold);
 	u16 v_idx;
 
-	cpumask_var_t affinity_mask;
 	__cacheline_group_end_aligned(cold);
 };
 libeth_cacheline_set_assert(struct idpf_q_vector, 120,
 			    24 + sizeof(struct napi_struct) +
 			    2 * sizeof(struct dim),
-			    8 + sizeof(cpumask_var_t));
+			    8);
 
 struct idpf_rx_queue_stats {
 	u64_stats_t packets;
@@ -940,7 +938,7 @@ static inline int idpf_q_vector_to_mem(const struct idpf_q_vector *q_vector)
 	if (!q_vector)
 		return NUMA_NO_NODE;
 
-	cpu = cpumask_first(q_vector->affinity_mask);
+	cpu = cpumask_first(&q_vector->napi.config->affinity_mask);
 
 	return cpu < nr_cpu_ids ? cpu_to_mem(cpu) : NUMA_NO_NODE;
 }
-- 
2.43.0

Re: [PATCH net-next v8 3/6] net: napi: add CPU affinity to napi_config

[Paolo Abeni]

On 2/11/25 10:06 PM, Ahmed Zaki wrote:
> @@ -394,10 +395,8 @@ struct napi_struct {
>  	struct list_head	dev_list;
>  	struct hlist_node	napi_hash_node;
>  	int			irq;
> -#ifdef CONFIG_RFS_ACCEL
>  	struct irq_affinity_notify notify;
>  	int			napi_rmap_idx;
> -#endif

I'm sorry for the late doubt, but it's not clear to me why you need to
add the #ifdef in the previous patch ?!?

> diff --git a/net/core/dev.c b/net/core/dev.c
> index 209296cef3cd..d2c942bbd5e6 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -6871,28 +6871,39 @@ void netif_queue_set_napi(struct net_device *dev, unsigned int queue_index,
>  }
>  EXPORT_SYMBOL(netif_queue_set_napi);
>  
> -#ifdef CONFIG_RFS_ACCEL
>  static void
> -netif_irq_cpu_rmap_notify(struct irq_affinity_notify *notify,
> -			  const cpumask_t *mask)
> +netif_napi_irq_notify(struct irq_affinity_notify *notify,
> +		      const cpumask_t *mask)
>  {
>  	struct napi_struct *napi =
>  		container_of(notify, struct napi_struct, notify);
> +#ifdef CONFIG_RFS_ACCEL
>  	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
>  	int err;
> +#endif
>  
> -	err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
> -	if (err)
> -		netdev_warn(napi->dev, "RMAP update failed (%d)\n",
> -			    err);
> +	if (napi->config && napi->dev->irq_affinity_auto)
> +		cpumask_copy(&napi->config->affinity_mask, mask);
> +
> +#ifdef CONFIG_RFS_ACCEL
> +	if (napi->dev->rx_cpu_rmap_auto) {
> +		err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
> +		if (err)
> +			netdev_warn(napi->dev, "RMAP update failed (%d)\n",
> +				    err);
> +	}
> +#endif

Minor nit: if you provide a netif_rx_cpu_rmap() helper returning
dev->rx_cpu_rmap or NULL for !CONFIG_RFS_ACCEL build, you can avoid the
above 2 ifdefs and possibly more below.

> @@ -6915,7 +6926,6 @@ static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
>  	if (rc)
>  		goto err_set;
>  
> -	set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);

Minor nit: I think it would be better if the previous patch would add
directly this line in netif_napi_set_irq_locked() (avoding the removal
here).

/P

Re: [PATCH net-next v8 3/6] net: napi: add CPU affinity to napi_config

[Ahmed Zaki]

On 2025-02-13 5:26 a.m., Paolo Abeni wrote:
> On 2/11/25 10:06 PM, Ahmed Zaki wrote:
>> @@ -394,10 +395,8 @@ struct napi_struct {
>>   	struct list_head	dev_list;
>>   	struct hlist_node	napi_hash_node;
>>   	int			irq;
>> -#ifdef CONFIG_RFS_ACCEL
>>   	struct irq_affinity_notify notify;
>>   	int			napi_rmap_idx;
>> -#endif
> 
> I'm sorry for the late doubt, but it's not clear to me why you need to
> add the #ifdef in the previous patch ?!?

It was there to make the code consistent, since the rmap and the 
notifier were only needed for ARFS.

It can be removed, although I am not sure if there would be any warnings 
since on !CONFIG_ARFS_ACCEL the fields would never be used.

> 
>> diff --git a/net/core/dev.c b/net/core/dev.c
>> index 209296cef3cd..d2c942bbd5e6 100644
>> --- a/net/core/dev.c
>> +++ b/net/core/dev.c
>> @@ -6871,28 +6871,39 @@ void netif_queue_set_napi(struct net_device *dev, unsigned int queue_index,
>>   }
>>   EXPORT_SYMBOL(netif_queue_set_napi);
>>   
>> -#ifdef CONFIG_RFS_ACCEL
>>   static void
>> -netif_irq_cpu_rmap_notify(struct irq_affinity_notify *notify,
>> -			  const cpumask_t *mask)
>> +netif_napi_irq_notify(struct irq_affinity_notify *notify,
>> +		      const cpumask_t *mask)
>>   {
>>   	struct napi_struct *napi =
>>   		container_of(notify, struct napi_struct, notify);
>> +#ifdef CONFIG_RFS_ACCEL
>>   	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
>>   	int err;
>> +#endif
>>   
>> -	err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
>> -	if (err)
>> -		netdev_warn(napi->dev, "RMAP update failed (%d)\n",
>> -			    err);
>> +	if (napi->config && napi->dev->irq_affinity_auto)
>> +		cpumask_copy(&napi->config->affinity_mask, mask);
>> +
>> +#ifdef CONFIG_RFS_ACCEL
>> +	if (napi->dev->rx_cpu_rmap_auto) {
>> +		err = cpu_rmap_update(rmap, napi->napi_rmap_idx, mask);
>> +		if (err)
>> +			netdev_warn(napi->dev, "RMAP update failed (%d)\n",
>> +				    err);
>> +	}
>> +#endif
> 
> Minor nit: if you provide a netif_rx_cpu_rmap() helper returning
> dev->rx_cpu_rmap or NULL for !CONFIG_RFS_ACCEL build, you can avoid the
> above 2 ifdefs and possibly more below.
> 

Thanks, I will add this if there is a new version.


>> @@ -6915,7 +6926,6 @@ static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
>>   	if (rc)
>>   		goto err_set;
>>   
>> -	set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);
> 
> Minor nit: I think it would be better if the previous patch would add
> directly this line in netif_napi_set_irq_locked() (avoding the removal
> here).
> 

yes, it just made more sense for that patch.

Re: [PATCH net-next v8 0/6] net: napi: add CPU affinity to napi->config

[Jakub Kicinski]

On Tue, 11 Feb 2025 14:06:51 -0700 Ahmed Zaki wrote:
> Drivers usually need to re-apply the user-set IRQ affinity to their IRQs
> after reset. However, since there can be only one IRQ affinity notifier
> for each IRQ, registering IRQ notifiers conflicts with the ARFS rmap
> management in the core (which also registers separate IRQ affinity
> notifiers).   

Could you extract all the core changes as a first patch of the series
(rmap and affinity together). And then have the driver conversion
patches follow? Obviously don't do it if it'd introduce transient
breakage. But I don't think it should, since core changes should
be a noop before any driver opts in.

The way it's split now makes the logic quite hard to review.

Re: [PATCH net-next v8 0/6] net: napi: add CPU affinity to napi->config

[Jakub Kicinski]

On Sat, 15 Feb 2025 09:41:54 -0800 Jakub Kicinski wrote:
> On Tue, 11 Feb 2025 14:06:51 -0700 Ahmed Zaki wrote:
> > Drivers usually need to re-apply the user-set IRQ affinity to their IRQs
> > after reset. However, since there can be only one IRQ affinity notifier
> > for each IRQ, registering IRQ notifiers conflicts with the ARFS rmap
> > management in the core (which also registers separate IRQ affinity
> > notifiers).     
> 
> Could you extract all the core changes as a first patch of the series
> (rmap and affinity together). And then have the driver conversion
> patches follow? Obviously don't do it if it'd introduce transient
> breakage. But I don't think it should, since core changes should
> be a noop before any driver opts in.
> 
> The way it's split now makes the logic quite hard to review.

Ah, and please add the patch with the ksft test I shared earlier to
your series:
https://github.com/kuba-moo/linux/commit/de7d2475750ac05b6e414d7e5201e354b05cf146
it just needs a commit message, I think. The prereq patches are 
in the tree now.

Re: [PATCH net-next v8 2/6] net: move ARFS rmap management to core

[Jakub Kicinski]

On Tue, 11 Feb 2025 14:06:53 -0700 Ahmed Zaki wrote:
> +static void netif_napi_affinity_release(struct kref *ref)
> +{
> +	struct napi_struct *napi =
> +		container_of(ref, struct napi_struct, notify.kref);
> +	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
> +

We should only get here from our own cleanup path, otherwise locking
and state sync may be a concern:

	netdev_assert_locked(dev);
	WARN_ON(test_and_clear_bit(NAPI_STATE_HAS_NOTIFIER,
				   &napi->state));

> +	rmap->obj[napi->napi_rmap_idx] = NULL;
> +	napi->napi_rmap_idx = -1;
> +	cpu_rmap_put(rmap);
> +}
> +
> +static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
> +{
> +	struct cpu_rmap *rmap = napi->dev->rx_cpu_rmap;
> +	int rc;
> +
> +	napi->notify.notify = netif_irq_cpu_rmap_notify;
> +	napi->notify.release = netif_napi_affinity_release;
> +	cpu_rmap_get(rmap);
> +	rc = cpu_rmap_add(rmap, napi);
> +	if (rc < 0)
> +		goto err_add;
> +
> +	napi->napi_rmap_idx = rc;
> +	rc = irq_set_affinity_notifier(irq, &napi->notify);
> +	if (rc)
> +		goto err_set;
> +
> +	set_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state);
> +	return 0;

some of this function is common with the code in 
netif_napi_set_irq_locked()
under 
	} else if (napi->dev->irq_affinity_auto) {

could you refactor this to avoid the duplication 
and make it clearer which parts differ?

> +err_set:
> +	rmap->obj[napi->napi_rmap_idx] = NULL;
> +	napi->napi_rmap_idx = -1;
> +err_add:
> +	cpu_rmap_put(rmap);
> +	return rc;
> +}
> +
> +int netif_enable_cpu_rmap(struct net_device *dev, unsigned int num_irqs)
> +{
> +	if (dev->rx_cpu_rmap_auto)
> +		return 0;
> +
> +	dev->rx_cpu_rmap = alloc_irq_cpu_rmap(num_irqs);
> +	if (!dev->rx_cpu_rmap)
> +		return -ENOMEM;
> +
> +	dev->rx_cpu_rmap_auto = true;
> +	return 0;
> +}
> +EXPORT_SYMBOL(netif_enable_cpu_rmap);
> +
> +static void netif_del_cpu_rmap(struct net_device *dev)
> +{
> +	struct cpu_rmap *rmap = dev->rx_cpu_rmap;
> +
> +	if (!dev->rx_cpu_rmap_auto)
> +		return;
> +
> +	/* Free the rmap */
> +	cpu_rmap_put(rmap);
> +	dev->rx_cpu_rmap = NULL;
> +	dev->rx_cpu_rmap_auto = false;
> +}
> +
> +#else
> +static int napi_irq_cpu_rmap_add(struct napi_struct *napi, int irq)
> +{
> +	return 0;
> +}
> +
> +int netif_enable_cpu_rmap(struct net_device *dev, unsigned int num_irqs)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL(netif_enable_cpu_rmap);
> +
> +static void netif_del_cpu_rmap(struct net_device *dev)
> +{
> +}
> +#endif
> +
> +void netif_napi_set_irq_locked(struct napi_struct *napi, int irq)
> +{
> +	int rc;

maybe netdev_assert_locked_or_invisible(napi->dev); ?

> +	if (napi->irq == irq)
> +		return;
> +
> +	/* Remove existing rmap entries */
> +	if (test_and_clear_bit(NAPI_STATE_HAS_NOTIFIER, &napi->state))
> +		irq_set_affinity_notifier(napi->irq, NULL);
> +
> +	napi->irq = irq;
> +	if (irq < 0)
> +		return;
> +
> +	rc = napi_irq_cpu_rmap_add(napi, irq);
> +	if (rc)
> +		netdev_warn(napi->dev, "Unable to update aRFS map (%d)\n", rc);
> +}
> +EXPORT_SYMBOL(netif_napi_set_irq_locked);
> +
>  static void napi_restore_config(struct napi_struct *n)
>  {
>  	n->defer_hard_irqs = n->config->defer_hard_irqs;

Re: [PATCH net-next v8 3/6] net: napi: add CPU affinity to napi_config

[Jakub Kicinski]

On Tue, 11 Feb 2025 14:06:54 -0700 Ahmed Zaki wrote:
> @@ -11575,9 +11615,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
>  		void (*setup)(struct net_device *),
>  		unsigned int txqs, unsigned int rxqs)
>  {
> +	unsigned int maxqs, i, numa;
>  	struct net_device *dev;
>  	size_t napi_config_sz;
> -	unsigned int maxqs;
>  
>  	BUG_ON(strlen(name) >= sizeof(dev->name));
>  
> @@ -11679,6 +11719,11 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
>  	if (!dev->napi_config)
>  		goto free_all;
>  
> +	numa = dev_to_node(&dev->dev);

Does this work? dev->dev is the "software" device, IOW the netdev itself.
The HW dev is dev->dev.parent but it won't be set at this stage, we'd
need to move the init to register, or maybe netif_enable_cpu_rmap() /
netif_set_affinity_auto() ?

> +	for (i = 0; i < maxqs; i++)
> +		cpumask_set_cpu(cpumask_local_spread(i, numa),
> +				&dev->napi_config[i].affinity_mask);