scsi: virtio: virtio_scsi: Set can_queue to the length of the virtqueue.

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Since switching to blk-mq as the default in commit 5c279bd9e4
("scsi: default to scsi-mq"), virtio-scsi LUNs consume about 10x as
much kernel memory.

qemu currently allocates a fixed 128 entry virtqueue.  can_queue
currently is set to 1024.  But with indirect descriptors, each command
in the queue takes 1 virtqueue entry, so the number of commands which
can be queued is equal to the length of the virtqueue.

Note I intend to send a patch to qemu to allow the virtqueue size to be
configured from the qemu command line.

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

...

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Richard W.M. Jones 2017-08-10 17:56:52 +01:00 • committed by Martin K. Petersen

parent 44ed8089e9

commit 582b0ab200

1 changed files with 2 additions and 2 deletions

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drivers/scsi/virtio_scsi.c

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