[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH t
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context |
Date: |
Fri, 13 Feb 2015 10:38:43 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
On 13/02/2015 02:21, Fam Zheng wrote:
>> Could you just do set_aio_context for all devices when starting
>> dataplane? For example with a new scsi_device_set_aio_context function
>> (and a new method in SCSIDeviceClass).
>>
>> Maybe I'm missing the obvious. :)
>
> Per VQ IOThread stills needs it, in the case that guest switches the VQ of a
> disk on the fly.
Per VQ iothread is far away though. Multiqueue aims at parallelizing
accesses *to the same disk from different CPUs*, not at parallelizing
accesses to different disks. As long as bdrv_set_aio_context does
bdrv_drain_all, something has to change for multiqueue dataplane: either
stop using bdrv_set_aio_context, or stop doing bdrv_drain_all.
In either case, the changes are large enough that we shouldn't code for
a case that doesn't exist yet.
In addition, making the code more similar for virtio-blk and virtio-scsi
dataplane is good, because the same changes can apply to both in the future.
Paolo
- [Qemu-devel] [PATCH 0/3] virtio-scsi: Fix unsafe bdrv_set_aio_context calls, Fam Zheng, 2015/02/12
- [Qemu-devel] [PATCH 2/3] virtio-scsi: Deduplicate cmd queue handling code of dataplane, Fam Zheng, 2015/02/12
- [Qemu-devel] [PATCH 1/3] block: Forbid bdrv_set_aio_context outside BQL, Fam Zheng, 2015/02/12
- [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Fam Zheng, 2015/02/12
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Paolo Bonzini, 2015/02/12
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Fam Zheng, 2015/02/12
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Fam Zheng, 2015/02/13
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Paolo Bonzini, 2015/02/13
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Fam Zheng, 2015/02/13
- Re: [Qemu-devel] [PATCH 3/3] virtio-scsi-dataplane: Use main thread BH to set BDS' aio context, Paolo Bonzini, 2015/02/13