> Subject: Re: Re: [PATCH] sched/fair: fix pick_eevdf to always find the
> correct se
>
> Hi Biju,
>
> On 2023-10-05 at 07:58:04 +0000, Biju Das wrote:
> > Hi all,
> >
> > > -----Original Message-----
> > > From: Biju Das
> > > Sent: Thursday, October 5, 2023 8:32 AM
> > > Subject: Re: [PATCH] sched/fair: fix pick_eevdf to always find the
> > > correct se
> > >
> > > Subject: Re: [PATCH] sched/fair: fix pick_eevdf to always find the
> > > correct se
> > > Date: Wed, 4 Oct 2023 22:39:39 +0200 [thread overview]
> > > Message-ID: <c92bc8a6-225d-4fd2-88b5-8994090fb2de@xxxxxxxxxxx> (raw)
> > > In-Reply-To: <xm261qego72d.fsf_-_@xxxxxxxxxx>
> > >
> > > Hi,
> > >
> > > On 30.09.2023 02:09, Benjamin Segall wrote:
> > > > The old pick_eevdf could fail to find the actual earliest eligible
> > > > deadline when it descended to the right looking for min_deadline,
> > > > but it turned out that that min_deadline wasn't actually eligible.
> > > > In that case we need to go back and search through any left
> > > > branches we skipped looking for the actual best _eligible_
> min_deadline.
> > > >
> > > > This is more expensive, but still O(log n), and at worst should
> > > > only involve descending two branches of the rbtree.
> > > >
> > > > I've run this through a userspace stress test (thank you
> > > > tools/lib/rbtree.c), so hopefully this implementation doesn't miss
> > > > any corner cases.
> > > >
> > > > Fixes: 147f3efaa241 ("sched/fair: Implement an EEVDF-like
> > > > scheduling
> > > > policy")
> > > > Signed-off-by: Ben Segall <bsegall@xxxxxxxxxx>
> > >
> > > This patch causing issues [1] in Renesas RZ/G2L SMARC EVK platform.
> > > Reverting the patch fixes the warning messages
> > >
>
> Thank you for reporting this. It seems to be directly triggered by the
> pr_err in __pick_eevdf(). May I have the kernel config file you are using?
> I'm trying to reproduce this issue on a server.
It is reproducible with [1] and [2]. The logs I shared from [2]
[1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm64/configs/defconfig?h=next-20231005
[2] https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel.git/tree/arch/arm64/configs/renesas_defconfig
Cheers,
Biju
