Messages in this thread | | | Date | Sat, 11 Mar 2023 11:49:07 -0600 | Subject | Re: [PATCH 00/11] Use copy_process in vhost layer | From | Mike Christie <> |
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On 3/11/23 11:21 AM, Linus Torvalds wrote: > On Fri, Mar 10, 2023 at 2:04 PM Mike Christie > <michael.christie@oracle.com> wrote: >> >> The following patches were made over Linus's tree and apply over next. They >> allow the vhost layer to use copy_process instead of using >> workqueue_structs to create worker threads for VM's devices. > > Ok, all these patches looked fine to me from a quick scan - nothing > that I reacted to as objectionable, and several of them looked like > nice cleanups. > > The only one I went "Why do you do it that way" for was in 10/11 > (entirely internal to vhost, so I don't feel too strongly about this) > how you made "struct vhost_worker" be a pointer in "struct vhost_dev". > > It _looks_ to me like it could just have been an embedded structure > rather than a separate allocation. > > IOW, why do > > vhost_dev->worker > > instead of doing > > vhost_dev.worker > > and just having it all in the same allocation? > > Not a big deal. Maybe you wanted the 'test if worker pointer is NULL' > code to stay around, and basically use that pointer as a flag too. Or > maybe there is some other reason you want to keep that separate.. >
There were 2 reasons: 1. Yeah, we needed a flag to indicate that the worker was not setup for the cases like where userspace just opens the dev then closes it without doing the IOCTL that does vhost_dev_set_owner.
2. I could have handled #1 by embedding the worker in the vhost_dev and then just testing worker.vtsk. However, I have a followup patchset that allows us to create multiple worker threads per device. For that patchset I then do:
- if (vhost_dev->worker)
+ if (vhost_dev->workers)
so I think it just saved me some typing.
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