Re: [Qemu-devel] [PATCH v8 0/6] fsdev: qmp interface for io throttling

[Alberto Garcia]

On Wed 30 Aug 2017 05:12:22 PM CEST, Pradeep Jagadeesh wrote:
> On 8/30/2017 5:10 PM, Alberto Garcia wrote:
>> On Wed 30 Aug 2017 05:07:29 PM CEST, Pradeep Jagadeesh wrote:
>>
>>> Thanks for the steps, I did reproduce the issue easily. Looking into
>>> the code, may be we also need to try the same with the block devices.
>>
>> I did some tests and it was working fine, so I'd suspect of the fsdev
>> code first.
>>
> OK, thanks for the clarification. I will look into fsdev code.

I just took a quick look at the code, the problem is almost certainly in
fsdev_set_io_throttle(): that doesn't simply update the config, it also
reinitializes the FsThrottle structure completely, creates new timers
and new throttled_reqs queues. If there were pending requests there
they're probably lost forever.

Take a look at blk_set_io_limits() and see how it is done for block
devices.

Berto