Re: [PATCH v3] sched/fair: fix unthrottle_cfs_rq for leaf_cfs_rq list

[Tao Zhou]

On Thu, Nov 19, 2020 at 07:50:15AM +0800, Tao Zhou wrote:
> On Wed, Nov 18, 2020 at 07:56:38PM -0300, Guilherme G. Piccoli wrote:
> > Hi Vincent (and all CCed), I'm sorry to ping about such "old" patch, but
> > we experienced a similar condition to what this patch addresses; it's an
> > older kernel (4.15.x) but when suggesting the users to move to an
> > updated 5.4.x kernel, we noticed that this patch is not there, although
> > similar ones are (like [0] and [1]).
> > 
> > So, I'd like to ask if there's any particular reason to not backport
> > this fix to stable kernels, specially the longterm 5.4. The main reason
> > behind the question is that the code is very complex for non-experienced
> > scheduler developers, and I'm afraid in suggesting such backport to 5.4
> > and introduce complex-to-debug issues.
> > 
> > Let me know your thoughts Vincent (and all CCed), thanks in advance.
> > Cheers,
> > 
> > 
> > Guilherme
> > 
> > 
> > P.S. For those that deleted this thread from the email client, here's a
> > link:
> > https://lore.kernel.org/lkml/20200513135528.4742-1-vincent.guittot@xxxxxxxxxx/
> > 
> > 
> > [0]
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe61468b2cb
> > 
> > [1]
> > https://lore.kernel.org/lkml/20200506141821.GA9773@xxxxxxxxxxxxxxxxxxxxxxxxx/
> > <- great thread BTW!
> 
> 'sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list" failed to apply to
> 5.4-stable tree'
> 
> You could check above. But I do not have the link about this. Can't search it
> on LKML web: https://lore.kernel.org/lkml/
> 
> BTW: 'ouwen210@xxxxxxxxxxx' and 'zohooouoto@xxxxxxxxxxx' all is myself.
> 
> Sorry for the confusing..
> 
> Thanks.

Sorry again. I forget something. It is in the stable.

Here it is:

  https://lore.kernel.org/stable/159041776924279@xxxxxxxxx/