From: Keith Busch <keith.busch@intel.com>
To: John Garry <john.garry@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>,
Marc Zyngier <marc.zyngier@arm.com>,
"axboe@kernel.dk" <axboe@kernel.dk>,
Peter Zijlstra <peterz@infradead.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Linuxarm <linuxarm@huawei.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Hannes Reinecke <hare@suse.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: Question on handling managed IRQs when hotplugging CPUs
Date: Tue, 5 Feb 2019 07:52:44 -0700 [thread overview]
Message-ID: <20190205145244.GB28023@localhost.localdomain> (raw)
In-Reply-To: <42d149c5-0380-c357-8811-81015159ac04@huawei.com>
On Tue, Feb 05, 2019 at 05:24:11AM -0800, John Garry wrote:
> On 04/02/2019 07:12, Hannes Reinecke wrote:
>
> Hi Hannes,
>
> >
> > So, as the user then has to wait for the system to declars 'ready for
> > CPU remove', why can't we just disable the SQ and wait for all I/O to
> > complete?
> > We can make it more fine-grained by just waiting on all outstanding I/O
> > on that SQ to complete, but waiting for all I/O should be good as an
> > initial try.
> > With that we wouldn't need to fiddle with driver internals, and could
> > make it pretty generic.
>
> I don't fully understand this idea - specifically, at which layer would
> we be waiting for all the IO to complete?
Whichever layer dispatched the IO to a CPU specific context should
be the one to wait for its completion. That should be blk-mq for most
block drivers.
next prev parent reply other threads:[~2019-02-05 14:53 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 11:25 Question on handling managed IRQs when hotplugging CPUs John Garry
2019-01-29 11:54 ` Hannes Reinecke
2019-01-29 12:01 ` Thomas Gleixner
2019-01-29 15:27 ` John Garry
2019-01-29 16:27 ` Thomas Gleixner
2019-01-29 17:23 ` John Garry
2019-01-29 15:44 ` Keith Busch
2019-01-29 17:12 ` John Garry
2019-01-29 17:20 ` Keith Busch
2019-01-30 10:38 ` John Garry
2019-01-30 12:43 ` Thomas Gleixner
2019-01-31 17:48 ` John Garry
2019-02-01 15:56 ` Hannes Reinecke
2019-02-01 21:57 ` Thomas Gleixner
2019-02-04 7:12 ` Hannes Reinecke
2019-02-05 13:24 ` John Garry
2019-02-05 14:52 ` Keith Busch [this message]
2019-02-05 15:09 ` John Garry
2019-02-05 15:11 ` Keith Busch
2019-02-05 15:15 ` Hannes Reinecke
2019-02-05 15:27 ` John Garry
2019-02-05 18:23 ` Christoph Hellwig
2019-02-06 9:21 ` John Garry
2019-02-06 13:34 ` Benjamin Block
2019-02-05 15:10 ` Hannes Reinecke
2019-02-05 15:16 ` Keith Busch
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