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Open Source and information security mailing list archives
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Date: Mon, 18 Sep 2017 00:02:33 +0000 From: KY Srinivasan <kys@...rosoft.com> To: Greg KH <gregkh@...uxfoundation.org> CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>, "olaf@...fle.de" <olaf@...fle.de>, "apw@...onical.com" <apw@...onical.com>, "vkuznets@...hat.com" <vkuznets@...hat.com>, "jasowang@...hat.com" <jasowang@...hat.com>, "leann.ogasawara@...onical.com" <leann.ogasawara@...onical.com>, "marcelo.cerri@...onical.com" <marcelo.cerri@...onical.com>, Stephen Hemminger <sthemmin@...rosoft.com>, Dexuan Cui <decui@...rosoft.com>, Haiyang Zhang <haiyangz@...rosoft.com> Subject: RE: [PATCH 2/5] vmbus: suppress uevents for hv_sock devices > -----Original Message----- > From: Greg KH [mailto:gregkh@...uxfoundation.org] > Sent: Sunday, September 10, 2017 1:10 AM > To: KY Srinivasan <kys@...rosoft.com> > Cc: linux-kernel@...r.kernel.org; devel@...uxdriverproject.org; > olaf@...fle.de; apw@...onical.com; vkuznets@...hat.com; > jasowang@...hat.com; leann.ogasawara@...onical.com; > marcelo.cerri@...onical.com; Stephen Hemminger > <sthemmin@...rosoft.com>; Dexuan Cui <decui@...rosoft.com>; Haiyang > Zhang <haiyangz@...rosoft.com> > Subject: Re: [PATCH 2/5] vmbus: suppress uevents for hv_sock devices > > On Sat, Sep 09, 2017 at 11:08:46PM -0700, kys@...hange.microsoft.com > wrote: > > From: Dexuan Cui <decui@...rosoft.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
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