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Message-ID: <8ed3a93804ca136690749edcb464a60d4149a4e8.camel@redhat.com>
Subject: Re: [PATCH v2 06/10] nvme/core: add mdev interfaces
From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     Christoph Hellwig <hch@lst.de>, Max Gurtovoy <maxg@mellanox.com>
Cc:     Fam Zheng <fam@euphon.net>, kvm@vger.kernel.org,
        Wolfram Sang <wsa@the-dreams.de>,
        linux-nvme@lists.infradead.org,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Keith Busch <keith.busch@intel.com>,
        Kirti Wankhede <kwankhede@nvidia.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        "Paul E . McKenney" <paulmck@linux.ibm.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Christoph Hellwig <hch@infradead.org>,
        Liang Cunming <cunming.liang@intel.com>,
        Jens Axboe <axboe@fb.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        John Ferlan <jferlan@redhat.com>,
        Liu Changpeng <changpeng.liu@intel.com>,
        Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        Amnon Ilan <ailan@redhat.com>,
        "David S . Miller" <davem@davemloft.net>
Date:   Mon, 06 May 2019 11:34:26 +0300
In-Reply-To: <1cc7efd1852f298b01f09955f2c4bf3b20cead13.camel@redhat.com>
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         <d1c0c7ae-1a7d-06e5-d8bb-765a7fd5e41d@mellanox.com>
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         <1cc7efd1852f298b01f09955f2c4bf3b20cead13.camel@redhat.com>
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On Mon, 2019-05-06 at 11:31 +0300, Maxim Levitsky wrote:
> On Sat, 2019-05-04 at 08:49 +0200, Christoph Hellwig wrote:
> > On Fri, May 03, 2019 at 10:00:54PM +0300, Max Gurtovoy wrote:
> > > Don't see a big difference of taking NVMe queue and namespace/partition
> > > to 
> > > guest OS or to P2P since IO is issued by external entity and pooled
> > > outside 
> > > the pci driver.
> > 
> > We are not going to the queue aside either way..  That is where the
> > last patch in this series is already working to, and which would be
> > the sensible vhost model to start with.
> 
> Why are you saying that? I actualy prefer to use a sepearate queue per
> software
> nvme controller, tat because of lower overhead (about half than going through
> the block layer) and it better at QoS as the separate queue (or even few
> queues
> if needed) will give the guest a mostly guaranteed slice of the bandwidth of
> the
> device.

Sorry for typos - I need more coffee :-)

Best regards,
	Maxim Levitsky