From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH]: Staging: hv: Allocate the vmbus irq dynamically Date: Fri, 18 Feb 2011 17:02:30 -0800 Message-ID: <20110219010230.GA2402@suse.de> References: <1297799735-25917-1-git-send-email-kys@microsoft.com> <20110218211423.GH796@kroah.com> <6E21E5352C11B742B20C142EB499E048011604@TK5EX14MBXC124.redmond.corp.microsoft.com> <20110218220724.GA28986@suse.de> <6E21E5352C11B742B20C142EB499E04801162F@TK5EX14MBXC124.redmond.corp.microsoft.com> <20110218222916.GA14244@suse.de> <6E21E5352C11B742B20C142EB499E048011693@TK5EX14MBXC124.redmond.corp.microsoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <6E21E5352C11B742B20C142EB499E048011693@TK5EX14MBXC124.redmond.corp.microsoft.com> Sender: linux-kernel-owner@vger.kernel.org To: KY Srinivasan Cc: Greg KH , "linux-kernel@vger.kernel.org" , "devel@linuxdriverproject.org" , "virtualization@lists.osdl.org" List-Id: virtualization@lists.linuxfoundation.org On Sat, Feb 19, 2011 at 12:56:16AM +0000, KY Srinivasan wrote: > > > > -----Original Message----- > > From: Greg KH [mailto:gregkh@suse.de] > > Sent: Friday, February 18, 2011 5:29 PM > > To: KY Srinivasan > > Cc: Greg KH; linux-kernel@vger.kernel.org; devel@linuxdriverproject.org; > > virtualization@lists.osdl.org > > Subject: Re: [PATCH]: Staging: hv: Allocate the vmbus irq dynamically > > > > On Fri, Feb 18, 2011 at 10:16:05PM +0000, KY Srinivasan wrote: > > > > > > > > > > -----Original Message----- > > > > From: Greg KH [mailto:gregkh@suse.de] > > > > Sent: Friday, February 18, 2011 5:07 PM > > > > To: KY Srinivasan > > > > Cc: Greg KH; linux-kernel@vger.kernel.org; devel@linuxdriverproject.org; > > > > virtualization@lists.osdl.org > > > > Subject: Re: [PATCH]: Staging: hv: Allocate the vmbus irq dynamically > > > > > > > > On Fri, Feb 18, 2011 at 10:00:04PM +0000, KY Srinivasan wrote: > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > From: Greg KH [mailto:greg@kroah.com] > > > > > > Sent: Friday, February 18, 2011 4:14 PM > > > > > > To: KY Srinivasan > > > > > > Cc: gregkh@suse.de; linux-kernel@vger.kernel.org; > > > > > > devel@linuxdriverproject.org; virtualization@lists.osdl.org > > > > > > Subject: Re: [PATCH]: Staging: hv: Allocate the vmbus irq dynamically > > > > > > > > > > > > On Tue, Feb 15, 2011 at 11:55:35AM -0800, K. Y. Srinivasan wrote: > > > > > > > > > > > > > > Signed-off-by: K. Y. Srinivasan > > > > > > > Signed-off-by: Haiyang Zhang > > > > > > > Signed-off-by: Hank Janssen > > > > > > > > > > > > You didn't run this through checkpatch.pl. > > > > > > > > > > > > Please do so and fix the warning it gives you. > > > > > Greg, I did run the checkpatch script against this patch and the only > > > > > complaint I got was with regards to the IRQF_SAMPLE_RANDOM flag that I > > > > > pass. As a virtual machine, this is the only external event that the > > > > > VM is going to see and so I chose to keep this flag. Is there > > > > > something that would replace this flag; looking at the Xen drivers > > > > > they do pass this flag. > > > > > > > > But that flag is going away, right? And this really can't be a valid > > > > source of entropy as the HV channel is pretty predictable. > > > > > > Is it going away? What would replace this. Is all interrupt sources considered > > > predictable? > > > > Did you read the file that the checkpatch script told you to about this > > entry? > > It is only after reading the document, I decided to keep that flag. Please > note this is not a question of some interrupt sources not being > a good source of entropy; for this VM this is the only source of interrupts. > The document on this flag talked about how people were incorrectly > marking their interrupt as an entropy source; in this case there is not much of a > choice. > > > > > > This is the only unpredictable thing happening in the VM and that is the reason > > > I chose to keep the flag. > > > > If you remove it, do we loose all entropy for the VM? > > > > > > If you are only using this because Xen does/did it, that's not a valid > > > > excuse :) > > > Surely, you are joking. > > > > Not at all. > > To set the record straight here, this flag is in the existing code. > After I ran checkpatch, I toyed with the idea of getting rid of this. Then I > decided to keep it for all the reasons I mentioned earlier. > > > > > > In any event I am sending you a new patch with that flag removed. > > > > Have you tested to see if you now loose all entropy, and it causes > > problems or not? > > I am glad you asked me to test it. When I remove this flag, the entropy goes down > significantly and this is not surprising. Looking at > /proc/sys/kernel/entropy/entropy_avail, with the original patch after a couple > of compiles the number would be in thousands. With that flag removed, > I have the VM up for about an hour, even after a couple of compiles, > the entropy number is yet to crack 200. > > Let me know how you want to proceed here. Ok, my fault, let's keep the original flag. Care to resend the patch you had originally sent? thanks, greg k-h