linux-kernel - [PATCH v4 6/9] virtio: blk/scsi: use block layer helpers to calculate num of queues

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Message-Id: <20241217-isolcpus-io-queues-v4-6-5d355fbb1e14@kernel.org>
Date: Tue, 17 Dec 2024 19:29:40 +0100
From: Daniel Wagner <wagi@...nel.org>
To: Jens Axboe <axboe@...nel.dk>, Keith Busch <kbusch@...nel.org>, 
 Christoph Hellwig <hch@....de>, Sagi Grimberg <sagi@...mberg.me>, 
 Kashyap Desai <kashyap.desai@...adcom.com>, 
 Sumit Saxena <sumit.saxena@...adcom.com>, 
 Shivasharan S <shivasharan.srikanteshwara@...adcom.com>, 
 Chandrakanth patil <chandrakanth.patil@...adcom.com>, 
 "Martin K. Petersen" <martin.petersen@...cle.com>, 
 Nilesh Javali <njavali@...vell.com>, GR-QLogic-Storage-Upstream@...vell.com, 
 Don Brace <don.brace@...rochip.com>, "Michael S. Tsirkin" <mst@...hat.com>, 
 Jason Wang <jasowang@...hat.com>, Paolo Bonzini <pbonzini@...hat.com>, 
 Stefan Hajnoczi <stefanha@...hat.com>, 
 Eugenio Pérez <eperezma@...hat.com>, 
 Xuan Zhuo <xuanzhuo@...ux.alibaba.com>, 
 Andrew Morton <akpm@...ux-foundation.org>, 
 Thomas Gleixner <tglx@...utronix.de>
Cc: Costa Shulyupin <costa.shul@...hat.com>, 
 Juri Lelli <juri.lelli@...hat.com>, 
 Valentin Schneider <vschneid@...hat.com>, Waiman Long <llong@...hat.com>, 
 Ming Lei <ming.lei@...hat.com>, 
 Michal Koutný <mkoutny@...e.com>, 
 Frederic Weisbecker <frederic@...nel.org>, Mel Gorman <mgorman@...e.de>, 
 Hannes Reinecke <hare@...e.de>, 
 Sridhar Balaraman <sbalaraman@...allelwireless.com>, 
 "brookxu.cn" <brookxu.cn@...il.com>, linux-kernel@...r.kernel.org, 
 linux-block@...r.kernel.org, linux-nvme@...ts.infradead.org, 
 megaraidlinux.pdl@...adcom.com, linux-scsi@...r.kernel.org, 
 storagedev@...rochip.com, virtualization@...ts.linux.dev, 
 Daniel Wagner <wagi@...nel.org>
Subject: [PATCH v4 6/9] virtio: blk/scsi: use block layer helpers to
 calculate num of queues

Multiqueue devices should only allocate queues for the housekeeping CPUs
when isolcpus=managed_irq is set. This avoids that the isolated CPUs get
disturbed with OS workload.

Use helpers which calculates the correct number of queues which should
be used when isolcpus is used.

Signed-off-by: Daniel Wagner <wagi@...nel.org>
---
 drivers/block/virtio_blk.c                | 5 ++---
 drivers/scsi/megaraid/megaraid_sas_base.c | 3 ++-
 drivers/scsi/virtio_scsi.c                | 1 +
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index ed514ff46dc82acd629ae594cb0fa097bd301a9b..0287ceaaf19972f3a18e81cd2e3252e4d539ba93 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -976,9 +976,8 @@ static int init_vq(struct virtio_blk *vblk)
 		return -EINVAL;
 	}

-	num_vqs = min_t(unsigned int,
-			min_not_zero(num_request_queues, nr_cpu_ids),
-			num_vqs);
+	num_vqs = blk_mq_num_possible_queues(
+			min_not_zero(num_request_queues, num_vqs));

 	num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 59d385e5a917979ae2f61f5db2c3355b9cab7e08..3ff0978b3acb5baf757fee25d9fccf4971976272 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -6236,7 +6236,8 @@ static int megasas_init_fw(struct megasas_instance *instance)
 		intr_coalescing = (scratch_pad_1 & MR_INTR_COALESCING_SUPPORT_OFFSET) ?
 								true : false;
 		if (intr_coalescing &&
-			(blk_mq_num_online_queues(0) >= MR_HIGH_IOPS_QUEUE_COUNT) &&
+			(blk_mq_num_online_queues(0) >=
+			 MR_HIGH_IOPS_QUEUE_COUNT) &&
 			(instance->msix_vectors == MEGASAS_MAX_MSIX_QUEUES))
 			instance->perf_mode = MR_BALANCED_PERF_MODE;
 		else
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 60be1a0c61836ba643adcf9ad8d5b68563a86cb1..46ca0b82f57ce2211c7e2817dd40ee34e65bcbf9 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -919,6 +919,7 @@ static int virtscsi_probe(struct virtio_device *vdev)
 	/* We need to know how many queues before we allocate. */
 	num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 	num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
+	num_queues = blk_mq_num_possible_queues(num_queues);

 	num_targets = virtscsi_config_get(vdev, max_target) + 1;

-- 
2.47.1