Re: [PATCH] xen-hvm: Allow disabling buffer_io_timer

["Durrant, Paul" <xadimgnik@gmail.com>]

On 26/01/2022 13:43, Jason Andryuk wrote:
> On Tue, Dec 14, 2021 at 8:40 AM Durrant, Paul <xadimgnik@gmail.com> wrote:
>>
>> On 10/12/2021 11:34, Jason Andryuk wrote:
>>> commit f37f29d31488 "xen: slightly simplify bufioreq handling" hard
>>> coded setting req.count = 1 during initial field setup before the main
>>> loop.  This missed a subtlety that an early exit from the loop when
>>> there are no ioreqs to process, would have req.count == 0 for the return
>>> value.  handle_buffered_io() would then remove state->buffered_io_timer.
>>> Instead handle_buffered_iopage() is basically always returning true and
>>> handle_buffered_io() always re-setting the timer.
>>>
>>> Restore the disabling of the timer by introducing a new handled_ioreq
>>> boolean and use as the return value.  The named variable will more
>>> clearly show the intent of the code.
>>>
>>> Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
>>
>> Reviewed-by: Paul Durrant <paul@xen.org>
> 
> Thanks, Paul.
> 
> What is the next step for getting this into QEMU?
> 

Anthony, can you queue this?

   Paul

> To re-state more plainly, this patch fixes a bug to let QEMU go idle
> for longer stretches of time.  Without it, buffer_io_timer continues
> to re-arm and fire every 100ms even if there is nothing to do.
> 
> Regards,
> Jason