linux-kernel - [PATCH v2 7/8] nvme-pci: add module parameter for default moderation mode

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Message-ID: <20251116182839.939139-8-lrizzo@google.com>
Date: Sun, 16 Nov 2025 18:28:38 +0000
From: Luigi Rizzo <lrizzo@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>, Marc Zyngier <maz@...nel.org>, 
	Luigi Rizzo <rizzo.unipi@...il.com>, Paolo Abeni <pabeni@...hat.com>, 
	Andrew Morton <akpm@...ux-foundation.org>, Sean Christopherson <seanjc@...gle.com>, 
	Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org, 
	Bjorn Helgaas <bhelgaas@...gle.com>, Willem de Bruijn <willemb@...gle.com>, 
	Luigi Rizzo <lrizzo@...gle.com>
Subject: [PATCH v2 7/8] nvme-pci: add module parameter for default moderation mode

The following module parameter enables moderation at boot time for nvme devices.

  nvme.soft_moderation=1

It can be overridden at runtime via /proc/irq/*/*nvme*/soft_moderation.
See Documentation/core-api/irq/irq-moderation.rst for configuration.

Change-Id: Ib061737415c26b868e889d4d9953e1d25ca8fc4b
Signed-off-by: Luigi Rizzo <lrizzo@...gle.com>
---
 drivers/nvme/host/pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 72fb675a696f4..b9d7bce30061f 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -72,6 +72,8 @@
 static_assert(MAX_PRP_RANGE / NVME_CTRL_PAGE_SIZE <=
 	(1 /* prp1 */ + NVME_MAX_NR_DESCRIPTORS * PRPS_PER_PAGE));
 
+DEFINE_IRQ_MODERATION_MODE_PARAMETER;
+
 static int use_threaded_interrupts;
 module_param(use_threaded_interrupts, int, 0444);
 
@@ -1989,6 +1991,7 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
 		result = queue_request_irq(nvmeq);
 		if (result < 0)
 			goto release_sq;
+		IRQ_MODERATION_SET_DEFAULT_MODE(pci_irq_vector(to_pci_dev(dev->dev), vector));
 	}
 
 	set_bit(NVMEQ_ENABLED, &nvmeq->flags);
-- 
2.52.0.rc1.455.g30608eb744-goog