From: Borislav Petkov <bp@alien8.de>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
x86 <x86@kernel.org>
Subject: Re: [tip: core/rcu] rcu: Enable tick for nohz_full CPUs slow to provide expedited QS
Date: Sat, 25 Jan 2020 18:54:42 +0100 [thread overview]
Message-ID: <20200125175442.GA4369@zn.tnic> (raw)
In-Reply-To: <20200125161050.GE2935@paulmck-ThinkPad-P72>
On Sat, Jan 25, 2020 at 08:10:50AM -0800, Paul E. McKenney wrote:
> How big? (Seriously, given that the fix may depend on the number of CPUs.)
[ 7.660017] smp: Brought up 2 nodes, 256 CPUs
> So the problem appears to be that some of the boot-time processing
> is looping in the kernel, which is preventing the grace period from
> completing. One could argue that such code should be fixed, but on the
> other hand, boot time is a bit special. Later in -rcu's dev branch,
> there are commits that forgive this boot-time misbehavior, but this is
> a bit late in process to dump all of those commits into -tip.
Aha.
> The RT guys might need the warning, and it was them that I was thinking
> of when adding it.
But "boot time is a bit special". Or do they care about deadlines during
boot too?
> But let's see what works for mainline first. And
> since your box was booting fine without the warning before, I bet that
> it boots just fine with that warning removed.
Yes, it does.
> So could you please try out the (untested) patch below?
Warning's gone.
> If that works, I will re-introduce the warning with proper protection
> for the merge window following this coming one.
My big box is at your service if you need stuff tested later.
Thx Paul.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-01-25 17:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-25 10:42 tip-bot2 for Paul E. McKenney
2020-01-25 13:14 ` Borislav Petkov
2020-01-25 16:10 ` Paul E. McKenney
2020-01-25 17:54 ` Borislav Petkov [this message]
2020-01-25 19:48 ` Paul E. McKenney
2020-01-25 20:08 ` Paul E. McKenney
2020-01-25 20:23 ` Borislav Petkov
2020-01-25 20:19 ` Borislav Petkov
2020-01-26 1:43 ` Paul E. McKenney
2020-01-26 11:25 ` Borislav Petkov
2020-01-26 15:28 ` Paul E. McKenney
2020-01-26 17:19 ` Borislav Petkov
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