From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <llong@redhat.com>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Darren Hart" <dvhart@infradead.org>,
"Davidlohr Bueso" <dave@stgolabs.net>,
"André Almeida" <andrealmeid@igalia.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
"Valentin Schneider" <vschneid@redhat.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Juri Lelli" <juri.lelli@redhat.com>
Subject: Re: Futex hash_bucket lock can break isolation and cause priority inversion on RT
Date: Wed, 9 Oct 2024 09:22:13 +0200 [thread overview]
Message-ID: <20241009072213.GF17263@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <5f125ed8-66bb-4654-b1da-b8db643b81d6@redhat.com>
On Tue, Oct 08, 2024 at 03:44:23PM -0400, Waiman Long wrote:
>
> On 10/8/24 1:38 PM, Peter Zijlstra wrote:
> > On Tue, Oct 08, 2024 at 04:22:26PM +0100, Juri Lelli wrote:
> > > Does this report make any sense? If it does, has this issue ever been
> > > reported and possibly discussed? I guess it’s kind of a corner case, but
> > > I wonder if anybody has suggestions already on how to possibly try to
> > > tackle it from a kernel perspective.
> > Any shared lock can cause such havoc. Futex hash buckets is just one of
> > a number of very popular ones that's relatively easy to hit.
> >
> > I do have some futex-numa patches still pending, but they won't
> > magically sure this either. Userspace needs help at the very least.
>
> Regarding the futex-numa patches, are you planning to get them merged soon?
> We have customers asking for that.
They're on the todo list somewhere... I know Ampere had interest, other
than that nobody really said anything.
next prev parent reply other threads:[~2024-10-09 7:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-08 15:22 Futex hash_bucket lock can break isolation and cause priority inversion on RT Juri Lelli
2024-10-08 15:38 ` André Almeida
2024-10-08 15:51 ` Sebastian Andrzej Siewior
2024-10-08 15:59 ` André Almeida
2024-10-08 18:09 ` Sebastian Andrzej Siewior
2024-10-09 8:36 ` Juri Lelli
2024-10-24 22:36 ` Thomas Gleixner
2024-10-08 17:38 ` Peter Zijlstra
2024-10-08 19:44 ` Waiman Long
2024-10-09 7:22 ` Peter Zijlstra [this message]
2024-10-09 8:26 ` Juri Lelli
2024-10-08 18:30 ` Waiman Long
2024-10-09 8:28 ` Juri Lelli
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