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From: Thomas Gleixner <tglx@linutronix.de>
To: Keith Busch <keith.busch@intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [BUG 4.15-rc7] IRQ matrix management errors
Date: Wed, 17 Jan 2018 10:24:06 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1801171020440.1777@nanos> (raw)
In-Reply-To: <20180117075500.GB7562@localhost.localdomain>

On Wed, 17 Jan 2018, Keith Busch wrote:
> On Wed, Jan 17, 2018 at 08:34:22AM +0100, Thomas Gleixner wrote:
> > Can you trace the matrix allocations from the very beginning or tell me how
> > to reproduce. I'd like to figure out why this is happening.
> 
> Sure, I'll get the irq_matrix events.
> 
> I reproduce this on a machine with 112 CPUs and 3 NVMe controllers. The
> first two NVMe want 112 MSI-x vectors, and the last only 31 vectors. The
> test runs 'modprobe nvme' and 'modprobe -r nvme' in a loop with 10
> second delay between each step. Repro occurs within a few iterations,
> sometimes already broken after the initial boot.

That doesn't sound right. The vectors should be spread evenly accross the
CPUs. So ENOSPC should never happen.

Can you please take snapshots of /sys/kernel/debug/irq/ between the
modprobe and modprobe -r steps?

Thanks,

	tglx

  reply	other threads:[~2018-01-17  9:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20180115025759.GG13580@localhost.localdomain>
2018-01-15  3:02 ` [BUG 4.15-rc7] IRQ matrix management errors Keith Busch
2018-01-15  9:13   ` Thomas Gleixner
2018-01-16  6:16     ` Keith Busch
2018-01-16  7:11       ` Keith Busch
2018-01-16 10:33         ` Thomas Gleixner
2018-01-16 11:20           ` Thomas Gleixner
2018-01-16 14:26             ` Keith Busch
2018-01-17  2:25             ` Keith Busch
2018-01-17  7:34               ` Thomas Gleixner
2018-01-17  7:55                 ` Keith Busch
2018-01-17  9:24                   ` Thomas Gleixner [this message]
2018-01-17  9:32                     ` Thomas Gleixner
2018-01-17 14:24                       ` Keith Busch
2018-01-17 15:01                         ` Thomas Gleixner
2018-01-18  2:37                           ` Keith Busch
2018-01-18  8:10                             ` Thomas Gleixner
2018-01-18  8:48                               ` Keith Busch
2018-01-18  9:06                                 ` Thomas Gleixner
2018-01-18 10:43                           ` [tip:irq/urgent] irq/matrix: Spread interrupts on allocation tip-bot for Thomas Gleixner
2018-01-17 11:15             ` [tip:x86/urgent] x86/apic/vector: Fix off by one in error path tip-bot for Thomas Gleixner

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