From: "Michael S. Tsirkin" <mst@redhat.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>,
Max Gurtovoy <mgurtovoy@nvidia.com>,
hch@infradead.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, stefanha@redhat.com, israelr@nvidia.com,
nitzanc@nvidia.com, oren@nvidia.com, linux-block@vger.kernel.org,
axboe@kernel.dk
Subject: Re: [PATCH v3 1/1] virtio-blk: add num_request_queues module parameter
Date: Sun, 5 Sep 2021 11:15:16 -0400 [thread overview]
Message-ID: <20210905111415-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <YTSZ6CYM6BCsbVmk@unreal>
On Sun, Sep 05, 2021 at 01:20:24PM +0300, Leon Romanovsky wrote:
> On Sun, Sep 05, 2021 at 01:49:46AM -0700, Chaitanya Kulkarni wrote:
> >
> > On 9/5/2021 12:46 AM, Leon Romanovsky wrote:
> > > > +static unsigned int num_request_queues;
> > > > +module_param_cb(num_request_queues, &queue_count_ops, &num_request_queues,
> > > > + 0644);
> > > > +MODULE_PARM_DESC(num_request_queues,
> > > > + "Number of request queues to use for blk device. Should > 0");
> > > > +
> > > Won't it limit all virtio block devices to the same limit?
> > >
> > > It is very common to see multiple virtio-blk devices on the same system
> > > and they probably need different limits.
> > >
> > > Thanks
> >
> >
> > Without looking into the code, that can be done adding a configfs
> >
> > interface and overriding a global value (module param) when it is set from
> >
> > configfs.
>
> So why should we do double work instead of providing one working
> interface from the beginning?
>
> Thanks
>
> >
> >
The main way to do it is really from the hypervisor. This one
is a pretty blunt instrument, Max here says it's useful to reduce
memory usage of the driver. If that's the usecase then a global limit
seems sufficient.
--
MST
next prev parent reply other threads:[~2021-09-05 15:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 20:46 [PATCH v3 1/1] virtio-blk: add num_request_queues module parameter Max Gurtovoy
2021-09-03 6:06 ` Pankaj Gupta
2021-09-05 7:46 ` Leon Romanovsky
2021-09-05 8:49 ` Chaitanya Kulkarni
2021-09-05 9:19 ` Max Gurtovoy
2021-09-05 10:19 ` Leon Romanovsky
2021-09-05 11:16 ` Max Gurtovoy
2021-09-05 13:10 ` Leon Romanovsky
2021-09-05 13:16 ` Max Gurtovoy
2021-09-05 10:20 ` Leon Romanovsky
2021-09-05 15:15 ` Michael S. Tsirkin [this message]
2021-09-07 23:04 ` Leon Romanovsky
2021-10-22 9:30 ` Michael S. Tsirkin
2021-10-24 7:19 ` Max Gurtovoy
2021-10-24 8:12 ` Max Gurtovoy
2021-10-24 8:48 ` Michael S. Tsirkin
2021-10-24 10:57 ` Max Gurtovoy
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