Re: [PATCH] block/stream: Drain subtree around graph change

[Emanuele Giuseppe Esposito]

Am 05/04/2022 um 12:14 schrieb Kevin Wolf:
> I think all of this is really relevant for Emanuele's work, which
> involves adding AIO_WAIT_WHILE() deep inside graph update functions. I
> fully expect that we would see very similar problems, and just stacking
> drain sections over drain sections that might happen to usually fix
> things, but aren't guaranteed to, doesn't look like a good solution.

Yes, I think at this point we all agreed to drop subtree_drain as
replacement for AioContext.

The alternative is what Paolo proposed in the other thread " Removal of
AioContext lock, bs->parents and ->children: proof of concept"
I am not sure which thread you replied first :)

I think that proposal is not far from your idea, and it avoids to
introduce or even use drains at all.
Not sure why you called it a "step backwards even from AioContext locks".

Emanuele