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From: Ming Lei <ming.lei@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@fb.com>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>,
	Laurence Oberman <loberman@redhat.com>,
	Mike Snitzer <snitzer@redhat.com>
Subject: Re: [PATCH 0/2] genirq/affinity: try to make sure online CPU is assgined to irq vector
Date: Tue, 16 Jan 2018 09:34:40 +0800	[thread overview]
Message-ID: <20180116013439.GB3213@ming.t460p> (raw)
In-Reply-To: <alpine.DEB.2.20.1801151842080.2143@nanos>

On Mon, Jan 15, 2018 at 06:43:47PM +0100, Thomas Gleixner wrote:
> On Tue, 16 Jan 2018, Ming Lei wrote:
> > These two patches fixes IO hang issue reported by Laurence.
> > 
> > 84676c1f21 ("genirq/affinity: assign vectors to all possible CPUs")
> > may cause one irq vector assigned to all offline CPUs, then this vector
> > can't handle irq any more.
> > 
> > The 1st patch moves irq vectors spread into one function, and prepares
> > for the fix done in 2nd patch.
> > 
> > The 2nd patch fixes the issue by trying to make sure online CPUs assigned
> > to irq vector.
> 
> Which means it's completely undoing the intent and mechanism of managed
> interrupts. Not going to happen.

As I replied in previous mail, some of offline CPUs may be assigned to
some of irq vectors after we assign vectors to all possible CPUs, some
of which are not present.

> 
> Which driver is that which abuses managed interrupts and does not keep its
> queues properly sorted on cpu hotplug?

It isn't related with driver/device, and I can trigger this issue on NVMe
easily except for HPSA.


Thanks,
Ming

      parent reply	other threads:[~2018-01-16  1:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-15 16:03 [PATCH 0/2] genirq/affinity: try to make sure online CPU is assgined to irq vector Ming Lei
2018-01-15 16:03 ` [PATCH 1/2] genirq/affinity: move irq vectors spread into one function Ming Lei
2018-01-15 16:03 ` [PATCH 2/2] genirq/affinity: try best to make sure online CPU is assigned to vector Ming Lei
2018-01-15 17:40 ` [PATCH 0/2] genirq/affinity: try to make sure online CPU is assgined to irq vector Christoph Hellwig
2018-01-16  1:30   ` Ming Lei
2018-01-16 11:25     ` Thomas Gleixner
2018-01-16 12:23       ` Ming Lei
2018-01-16 13:28       ` Laurence Oberman
2018-01-16 15:22         ` Don Brace
2018-01-16 15:35           ` Laurence Oberman
2018-01-16 15:47           ` Ming Lei
2018-02-01 10:36           ` Ming Lei
2018-02-01 14:53             ` Don Brace
2018-02-01 15:04               ` Ming Lei
2018-01-16  2:15   ` Ming Lei
2018-01-15 17:43 ` Thomas Gleixner
2018-01-15 17:54   ` Laurence Oberman
2018-01-16  1:34   ` Ming Lei [this message]

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