lkml.org 
[lkml]   [2017]   [Sep]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH 2/5] vmbus: suppress uevents for hv_sock devices
Date


> -----Original Message-----
> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> Sent: Sunday, September 10, 2017 1:10 AM
> To: KY Srinivasan <kys@microsoft.com>
> Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> olaf@aepfle.de; apw@canonical.com; vkuznets@redhat.com;
> jasowang@redhat.com; leann.ogasawara@canonical.com;
> marcelo.cerri@canonical.com; Stephen Hemminger
> <sthemmin@microsoft.com>; Dexuan Cui <decui@microsoft.com>; Haiyang
> Zhang <haiyangz@microsoft.com>
> Subject: Re: [PATCH 2/5] vmbus: suppress uevents for hv_sock devices
>
> On Sat, Sep 09, 2017 at 11:08:46PM -0700, kys@exchange.microsoft.com
> wrote:
> > From: Dexuan Cui <decui@microsoft.com>
> >
> > hv_sock driver is automatically loaded when an application creates an
> > AF_VSOCK socket, so we don't really need to trigger uevents to the user
> > space udevd.
> >
> > And hv_sock devices can appear and disappear frequency, e.g. 100 per
> > second, so triggering the udevents can cause a high cpu utilization of
> > udevd, e.g. 30% on a 2-cpu virtual machine. So let's suppress the
> > uevents to avoid this.
>
> 100 per second for a struct device? That's crazy, and the uevent is the
> least of your worries. Please fix that, as it's not the correct way to
> use the driver model at all.
>
> And really, why is uevent taking all that much cpu time anyway? It
> _should_ be pretty fast, unless your distro is doing crazy things with
> it...
>
> sorry, am not going to take this patch.

Greg,

This is not a real problem that needs fixing. The test automation triggered this condition.
I will drop this patch and send the rest.

Regards,

K. Y
>
> greg k-h

\
 
 \ /
  Last update: 2017-09-18 02:03    [W:0.189 / U:0.176 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site