accel/habanalabs/gaudi2: add interrupt affinity for user interrupts

User interrupts are MSIx interrupts coming from Gaudi2, that have
specific range of IDs and are assigned to the sole use of the user
process that opened the Gaudi2 device (reminder: there can be only
a single user process running on Gaudi2 at any given time).

The interrupts are allocated and managed by the driver and therefore,
the user expects the driver to initialize them properly, which also
includes setting the affinity to the related CPU cores of the
device's NUMA node to get maximum performance.
Signed-off-by: Dani Liberman <dliberman@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

drivers/accel/habanalabs/common/device.c

@@ -2801,3 +2801,35 @@ void hl_enable_err_info_capture(struct hl_error_info *captured_err_info)
 	atomic_set(&captured_err_info->cs_timeout.write_enable, 1);
 	captured_err_info->undef_opcode.write_enable = true;
 }
+
+void hl_init_cpu_for_irq(struct hl_device *hdev)
+{
+#ifdef CONFIG_NUMA
+	struct cpumask *available_mask = &hdev->irq_affinity_mask;
+	int numa_node = hdev->pdev->dev.numa_node, i;
+	static struct cpumask cpu_mask;
+
+	if (numa_node < 0)
+		return;
+
+	if (!cpumask_and(&cpu_mask, cpumask_of_node(numa_node), cpu_online_mask)) {
+		dev_err(hdev->dev, "No available affinities in current numa node\n");
+		return;
+	}
+
+	/* Remove HT siblings */
+	for_each_cpu(i, &cpu_mask)
+		cpumask_set_cpu(cpumask_first(topology_sibling_cpumask(i)), available_mask);
+#endif
+}
+
+void hl_set_irq_affinity(struct hl_device *hdev, int irq)
+{
+	if (cpumask_empty(&hdev->irq_affinity_mask)) {
+		dev_dbg(hdev->dev, "affinity mask is empty\n");
+		return;
+	}
+
+	if (irq_set_affinity_hint(irq, &hdev->irq_affinity_mask))
+		dev_err(hdev->dev, "Failed setting irq %d affinity\n", irq);
+}

drivers/accel/habanalabs/common/habanalabs.h

@@ -3257,6 +3257,7 @@ struct hl_reset_info {
  * @clk_throttling: holds information about current/previous clock throttling events
  * @captured_err_info: holds information about errors.
  * @reset_info: holds current device reset information.
+ * @irq_affinity_mask: mask of available CPU cores for user and decoder interrupt handling.
  * @stream_master_qid_arr: pointer to array with QIDs of master streams.
  * @fw_inner_major_ver: the major of current loaded preboot inner version.
  * @fw_inner_minor_ver: the minor of current loaded preboot inner version.
@@ -3446,6 +3447,8 @@ struct hl_device {
 
 	struct hl_reset_info		reset_info;
 
+	cpumask_t			irq_affinity_mask;
+
 	u32				*stream_master_qid_arr;
 	u32				fw_inner_major_ver;
 	u32				fw_inner_minor_ver;
@@ -4032,6 +4035,8 @@ void hl_handle_critical_hw_err(struct hl_device *hdev, u16 event_id, u64 *event_
 void hl_handle_fw_err(struct hl_device *hdev, struct hl_info_fw_err_info *info);
 void hl_capture_engine_err(struct hl_device *hdev, u16 engine_id, u16 error_count);
 void hl_enable_err_info_capture(struct hl_error_info *captured_err_info);
+void hl_init_cpu_for_irq(struct hl_device *hdev);
+void hl_set_irq_affinity(struct hl_device *hdev, int irq);
 
 #ifdef CONFIG_DEBUG_FS
 

drivers/accel/habanalabs/gaudi2/gaudi2.c

@@ -4254,6 +4254,8 @@ static int gaudi2_enable_msix(struct hl_device *hdev)
 	if (gaudi2->hw_cap_initialized & HW_CAP_MSIX)
 		return 0;
 
+	hl_init_cpu_for_irq(hdev);
+
 	rc = pci_alloc_irq_vectors(hdev->pdev, GAUDI2_MSIX_ENTRIES, GAUDI2_MSIX_ENTRIES,
 					PCI_IRQ_MSIX);
 	if (rc < 0) {
@@ -4307,6 +4309,7 @@ static int gaudi2_enable_msix(struct hl_device *hdev)
 			i++, j++, user_irq_init_cnt++) {
 
 		irq = pci_irq_vector(hdev->pdev, i);
+		hl_set_irq_affinity(hdev, irq);
 		rc = request_irq(irq, hl_irq_user_interrupt_handler, 0, gaudi2_irq_name(i),
 				&hdev->user_interrupt[j]);
 		if (rc) {
@@ -4333,6 +4336,7 @@ static int gaudi2_enable_msix(struct hl_device *hdev)
 			i < GAUDI2_IRQ_NUM_USER_FIRST + user_irq_init_cnt ; i++, j++) {
 
 		irq = pci_irq_vector(hdev->pdev, i);
+		irq_set_affinity_hint(irq, NULL);
 		free_irq(irq, &hdev->user_interrupt[j]);
 	}
 	irq = pci_irq_vector(hdev->pdev, GAUDI2_IRQ_NUM_UNEXPECTED_ERROR);
@@ -4413,6 +4417,7 @@ static void gaudi2_disable_msix(struct hl_device *hdev)
 			k < hdev->asic_prop.user_interrupt_count ; i++, j++, k++) {
 
 		irq = pci_irq_vector(hdev->pdev, i);
+		irq_set_affinity_hint(irq, NULL);
 		free_irq(irq, &hdev->user_interrupt[j]);
 	}