search for: num_queu

vscsi->num_queues counts the number of request virtqueue which does not include the control and event virtqueue. It is wrong to subtract VIRTIO_SCSI_VQ_BASE from vscsi->num_queues. This patch fixes the following panic. (qemu) device_del scsi0 BUG: unable to handle kernel NULL pointer dereference at 00000000...

vscsi->num_queues counts the number of request virtqueue which does not include the control and event virtqueue. It is wrong to subtract VIRTIO_SCSI_VQ_BASE from vscsi->num_queues. This patch fixes the following panic. (qemu) device_del scsi0 BUG: unable to handle kernel NULL pointer dereference at 00000000...

...Considering above reasons, this patch set limits the number of hw queues used by nr_cpu_ids for both virtio-blk and virtio-scsi. ------------------------------------------------------------- Here is test result of virtio-scsi: qemu cmdline: -smp 2,maxcpus=4, \ -device virtio-scsi-pci,id=scsi0,num_queues=8, \ -device scsi-hd,drive=drive0,bus=scsi0.0,channel=0,scsi-id=0,lun=0, \ -drive file=test.img,if=none,id=drive0 Although maxcpus=4 and num_queues=8, 4 queues are used while 2 interrupts are allocated. # cat /proc/interrupts ... ... 24: 0 0 PCI-MSI 65536-edge virtio0-...

...for that array. For example: struct virtio_scsi { ... struct virtio_scsi_vq req_vqs[]; }; Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes. So, replace the following form: sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues with: struct_size(vscsi, req_vqs, num_queues) This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo at embeddedor.com> --- drivers/scsi/virtio_scsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c...

...for that array. For example: struct virtio_scsi { ... struct virtio_scsi_vq req_vqs[]; }; Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes. So, replace the following form: sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues with: struct_size(vscsi, req_vqs, num_queues) This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo at embeddedor.com> --- drivers/scsi/virtio_scsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c...

When tag_set->nr_maps is 1, the block layer limits the number of hw queues by nr_cpu_ids. No matter how many hw queues are used by virtio-scsi, as it has (tag_set->nr_maps == 1), it can use at most nr_cpu_ids hw queues. In addition, specifically for pci scenario, when the 'num_queues' specified by qemu is more than maxcpus, virtio-scsi would not be able to allocate more than maxcpus vectors in order to have a vector for each queue. As a result, it falls back into MSI-X with one vector for config and one shared for queues. Considering above reasons, this patch limits the...

...host notification from each vq and processing host I/O are still kept in the per-device iothread context, the changes are based on qemu v2.0.0 release, and can be accessed from below tree: git://kernel.ubuntu.com/ming/qemu.git #v2.0.0-virtblk-dataplane-mq For enabling the multi-vq feature, 'num_queues=N' need to be added into '-device virtio-blk-pci ...' of qemu command line, and suggest to pass 'vectors=N+1' to keep one MSI irq vector per each vq, and the feature depends on x-data-plane. Fio(libaio, randread, iodepth=64, bs=4K, jobs=N) is run inside VM to verify the impro...

...host notification from each vq and processing host I/O are still kept in the per-device iothread context, the changes are based on qemu v2.0.0 release, and can be accessed from below tree: git://kernel.ubuntu.com/ming/qemu.git #v2.0.0-virtblk-dataplane-mq For enabling the multi-vq feature, 'num_queues=N' need to be added into '-device virtio-blk-pci ...' of qemu command line, and suggest to pass 'vectors=N+1' to keep one MSI irq vector per each vq, and the feature depends on x-data-plane. Fio(libaio, randread, iodepth=64, bs=4K, jobs=N) is run inside VM to verify the impro...

This series implements virtio-scsi queue steering, which gives performance improvements of up to 50% (measured both with QEMU and tcm_vhost backends). This version rebased on Rusty's virtio ring rework patches, which has already gone into virtio-next today. We hope this can go into virtio-next together with the virtio ring rework pathes. V7: respin to fix the patch apply error V6: rework

This series implements virtio-scsi queue steering, which gives performance improvements of up to 50% (measured both with QEMU and tcm_vhost backends). This version rebased on Rusty's virtio ring rework patches, which has already gone into virtio-next today. We hope this can go into virtio-next together with the virtio ring rework pathes. V7: respin to fix the patch apply error V6: rework

This is on top of Paolo and Nick's work. Current status: Works now (guest boots fine, no hang any more) with seabios's virtio-scsi disabled. Rebased to latest qemu.org/master Change details are in commit log. TODO: Make seabios happy. Paolo Bonzini (2): virtio-scsi: create VirtIOSCSICommon vhost-scsi: new device supporting the tcm_vhost Linux kernel module hw/Makefile.objs

This is on top of Paolo and Nick's work. Current status: Works now (guest boots fine, no hang any more) with seabios's virtio-scsi disabled. Rebased to latest qemu.org/master Change details are in commit log. TODO: Make seabios happy. Paolo Bonzini (2): virtio-scsi: create VirtIOSCSICommon vhost-scsi: new device supporting the tcm_vhost Linux kernel module hw/Makefile.objs

This is on top of Paolo and Nick's work. Current status: Basically, tcm_vhost + seabios works now. We still have one more issue, vhost_verify_ring_mappings fails. The hotplug also works with the latest tcm_vhost.ko hotplug patch. Asias He (1): disable vhost_verify_ring_mappings check Paolo Bonzini (2): virtio-scsi: create VirtIOSCSICommon vhost-scsi: new device supporting the

This is on top of Paolo and Nick's work. Current status: Basically, tcm_vhost + seabios works now. We still have one more issue, vhost_verify_ring_mappings fails. The hotplug also works with the latest tcm_vhost.ko hotplug patch. Asias He (1): disable vhost_verify_ring_mappings check Paolo Bonzini (2): virtio-scsi: create VirtIOSCSICommon vhost-scsi: new device supporting the

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi QEMU folks, The following is the patch series to support vhost-scsi-pci within the upstream QEMU tree. This includes the refactoring of existing virtio-scsi code from Paolo to allow a VirtIOSCSICommon structure that is shared amoungst existing virtio-scsi-pci device and new vhost-scsi-pci device code. Currently this code requires

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi QEMU folks, The following is the patch series to support vhost-scsi-pci within the upstream QEMU tree. This includes the refactoring of existing virtio-scsi code from Paolo to allow a VirtIOSCSICommon structure that is shared amoungst existing virtio-scsi-pci device and new vhost-scsi-pci device code. Currently this code requires

This series implements virtio-scsi queue steering, which gives performance improvements of up to 50% (measured both with QEMU and tcm_vhost backends). The patches build on top of the new virtio APIs at http://permalink.gmane.org/gmane.linux.kernel.virtualization/18431; the new API simplifies the locking of the virtio-scsi driver nicely, thus it makes sense to require them as a prerequisite.

This series implements virtio-scsi queue steering, which gives performance improvements of up to 50% (measured both with QEMU and tcm_vhost backends). The patches build on top of the new virtio APIs at http://permalink.gmane.org/gmane.linux.kernel.virtualization/18431; the new API simplifies the locking of the virtio-scsi driver nicely, thus it makes sense to require them as a prerequisite.

This series implements virtio-scsi queue steering, which gives performance improvements of up to 50% (measured both with QEMU and tcm_vhost backends). This version rebased on Rusty's virtio ring rework patches. We hope this can go into virtio-next together with the virtio ring rework pathes. V5: improving the grammar of 1/5 (Paolo) move the dropping of sg_elems to 'virtio-scsi: use

This series implements virtio-scsi queue steering, which gives performance improvements of up to 50% (measured both with QEMU and tcm_vhost backends). This version rebased on Rusty's virtio ring rework patches. We hope this can go into virtio-next together with the virtio ring rework pathes. V5: improving the grammar of 1/5 (Paolo) move the dropping of sg_elems to 'virtio-scsi: use