Re: FAILED: patch "[PATCH] sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list" failed to apply to 5.4-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Sun, Dec 06, 2020 at 12:54:57PM +0100, Vincent Guittot wrote:
> On Sun, 6 Dec 2020 at 12:47, Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, Dec 06, 2020 at 12:25:12PM +0100, Vincent Guittot wrote:
> > > On Sun, 6 Dec 2020 at 10:56, Greg KH <gregkh@linuxfoundation.org> wrote:
> > > >
> > > > On Mon, May 25, 2020 at 07:27:09PM +0200, Vincent Guittot wrote:
> > > > > Le lundi 25 mai 2020 à 16:42:49 (+0200), gregkh@linuxfoundation.org a écrit :
> > > > > >
> > > > > > The patch below does not apply to the 5.4-stable tree.
> > > > > > If someone wants it applied there, or to any other stable or longterm
> > > > > > tree, then please email the backport, including the original git commit
> > > > > > id to <stable@vger.kernel.org>.
> > > > >
> > > > > This patch needs  commit
> > > > >     b34cb07dde7c ("sched/fair: Fix enqueue_task_fair() warning some more")
> > > > > to be applied first. But then, it will not apply. The backport is :
> > > > >
> > > > > [ Upstream commit 39f23ce07b9355d05a64ae303ce20d1c4b92b957 upstream ]
> > > > >
> > > > > Although not exactly identical, unthrottle_cfs_rq() and enqueue_task_fair()
> > > > > are quite close and follow the same sequence for enqueuing an entity in the
> > > > > cfs hierarchy. Modify unthrottle_cfs_rq() to use the same pattern as
> > > > > enqueue_task_fair(). This fixes a problem already faced with the latter and
> > > > > add an optimization in the last for_each_sched_entity loop.
> > > > >
> > > > > Fixes: fe61468b2cb (sched/fair: Fix enqueue_task_fair warning)
> > > > > Reported-by Tao Zhou <zohooouoto@zoho.com.cn>
> > > > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > > > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > > > > Reviewed-by: Phil Auld <pauld@redhat.com>
> > > > > Reviewed-by: Ben Segall <bsegall@google.com>
> > > > > Link: https://lkml.kernel.org/r/20200513135528.4742-1-vincent.guittot@linaro.org
> > > > > ---
> > > > >  kernel/sched/fair.c | 36 ++++++++++++++++++++++++++++--------
> > > > >  1 file changed, 28 insertions(+), 8 deletions(-)
> > > >
> > > > This patch doesn't apply to the 5.4.y tree at all.  Can someone please
> > > > provide a working backport?
> > >
> > > It seems that commit b34cb07dde7c ("sched/fair: Fix
> > > enqueue_task_fair() warning some more") has already been applied back
> > > in May. But then, I'm able to apply this patch on top of
> > > v5.4.y/v5.4.81
> > >
> >
> > What is "this patch" here?  I tried to apply 39f23ce07b93 ("sched/fair:
> > Fix unthrottle_cfs_rq() for leaf_cfs_rq list") directly to the 5.4 tree
> > and it too did not apply.
> 
> commit 39f23ce07b93 ("sched/fair: Fix unthrottle_cfs_rq() for
> leaf_cfs_rq list") can't apply because there are several changes which
> are not fixes which have been applied since v5.4 on the same code.
> 
> This patch is the backport on v5.4 of the commit 39f23ce07b93

What is "this"?  I tried to apply the above patch to the 5.4.y tree, and
it didn't apply.  So I still do not understand what I can do here...

greg k-h