Re: [RFC PATCH v7 0/4] blk-iocost: BPF struct_ops cost model

[Tao Cui]

Hello, Tejun.

在 2026/9/30 00:27, Tejun Heo 写道:
> Hello, Tao.
> 
> On Tue, 29 Sep 2026 21:39:00 +0800, Tao Cui wrote:
>> To make sure I understood correctly: attaching switches the active
>> model to the attached BPF model, while model=linear and model=bpf
>> only switch between the attached model and the builtin model without
>> affecting the attachment itself.  The attachment survives enable=0,
>> and only .unreg removes it.  Please shout if I still got that wrong.
> 
> Yes, except that removing the device also removes the attachment, as
> ioc_rqos_exit() ejects the model.
> 

Thanks for confirming.  I had left out the device removal case in
the summary.  v8 keeps the attachment independent from controller state
and model selection; only .unreg and device removal (where
ioc_rqos_exit() ejects the model) remove the attachment.

Thanks.
Tao> Thanks.
> 
> --
> tejun