Re: [Qemu-devel] [PATCH RFC v3 2/8] block: Add aio_context field in ThrottleGroupMember

[Kevin Wolf]

Am 28.06.2017 um 14:15 hat Manos Pitsidianakis geschrieben:
> On Wed, Jun 28, 2017 at 01:27:36PM +0200, Kevin Wolf wrote:
> >Am 23.06.2017 um 14:46 hat Manos Pitsidianakis geschrieben:
> >>timer_cb() needs to know about the current Aio context of the throttle
> >>request that is woken up. In order to make ThrottleGroupMember backend
> >>agnostic, this information is stored in an aio_context field instead of
> >>accessing it from BlockBackend.
> >>
> >>Signed-off-by: Manos Pitsidianakis <address@hidden>
> >
> >You're copying the AioContext when the BlockBackend is registered for
> >the throttle group, but what keeps both sides in sync when the context
> >is changed later on? Don't we need to update the ThrottleGroupMember in
> >blk_set_aio_context?
> 
> blk_set_aio_context calls throttle_timers_attach_aio_context which
> updates this. Though as Alberto said util/throttle.c should not know
> about ThrottleGroupMember. This is not needed in the later patches
> because the ThrottleGroupMember's aio_context gets updated as a node
> in the driver's bdrv_attach_aio_context
> 
> We can add a new function in block/throttle.c that updates a
> member's aio context but I'm not sure if it's really needed if
> members are only used in throttle nodes.

Oh, I looked at the final state after the series instead of this very
commit, so I missed the existing calls in blk_set_aio_context().

My bad, sorry for the noise.

Kevin

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