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Message-ID: <e0491452300bca37a716499b6ecd4e9f1c2f8c99.camel@redhat.com>
Subject: Re: [PATCH 0/9] RFC: NVME VFIO mediated device
From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     Bart Van Assche <bvanassche@acm.org>,
        linux-nvme@lists.infradead.org
Cc:     Fam Zheng <fam@euphon.net>, Keith Busch <keith.busch@intel.com>,
        Sagi Grimberg <sagi@grimberg.me>, kvm@vger.kernel.org,
        "David S . Miller" <davem@davemloft.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Liang Cunming <cunming.liang@intel.com>,
        Wolfram Sang <wsa@the-dreams.de>, linux-kernel@vger.kernel.org,
        Kirti Wankhede <kwankhede@nvidia.com>,
        Jens Axboe <axboe@fb.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        John Ferlan <jferlan@redhat.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Liu Changpeng <changpeng.liu@intel.com>,
        "Paul E . McKenney" <paulmck@linux.ibm.com>,
        Amnon Ilan <ailan@redhat.com>, Christoph Hellwig <hch@lst.de>,
        Nicolas Ferre <nicolas.ferre@microchip.com>
Date:   Wed, 20 Mar 2019 18:48:17 +0200
In-Reply-To: <1553094528.65329.29.camel@acm.org>
References: <20190319144116.400-1-mlevitsk@redhat.com>
         <1553094528.65329.29.camel@acm.org>
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On Wed, 2019-03-20 at 08:08 -0700, Bart Van Assche wrote:
> On Tue, 2019-03-19 at 16:41 +0200, Maxim Levitsky wrote:
> > * Polling kernel thread is used. The polling is stopped after a 
> > predefined timeout (1/2 sec by default).
> > Support for all interrupt driven mode is planned, and it shows promising
> > results.
> 
> Which cgroup will the CPU cycles used for polling be attributed to? Can the
> polling code be moved into user space such that it becomes easy to identify
> which process needs most CPU cycles for polling and such that the polling
> CPU cycles are attributed to the proper cgroup?


Currently there is a single IO thread per each virtual controller instance.
I would prefer to keep all the driver in the kernel, but I think I can make it
cgroup aware, in a simiar way this is done in vhost-net, and vhost-scsi.

Best regards,
	Maxim Levitsky


> Thanks,
> 
> Bart.