From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [UNTESTED] KVM: do not call kvm_set_irq from irq disabled section Date: Fri, 23 Apr 2010 16:30:43 +0300 Message-ID: <4BD1A103.5040507@redhat.com> References: <201004211548.12824.sheng.yang@intel.com> <20100421155840.GA22052@amt.cnet> <20100421171227.GB10744@redhat.com> <20100421173734.GA27425@amt.cnet> <20100421175848.GB2455@redhat.com> <20100421182911.GA28343@amt.cnet> <20100421183839.GC2455@redhat.com> <20100422164038.GA1117@amt.cnet> <20100422181130.GD2455@redhat.com> <20100422194030.GA4616@amt.cnet> <20100422195514.GE2455@redhat.com> <4BD17F0D.5070201@redhat.com> <4BD19A4E.2020402@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , Marcelo Tosatti , "Yang, Sheng" , kvm , "bonenkamp@gmx.de" , Chris Wright To: Chris Lalancette Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60003 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756249Ab0DWNau (ORCPT ); Fri, 23 Apr 2010 09:30:50 -0400 In-Reply-To: <4BD19A4E.2020402@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 04/23/2010 04:02 PM, Chris Lalancette wrote: > On 04/23/2010 07:05 AM, Avi Kivity wrote: > >> On 04/22/2010 10:55 PM, Gleb Natapov wrote: >> >>> >>> >>>>> What about converting PIC/IOAPIC mutexes into spinlocks? >>>>> >>>>> >>>> Works for me, but on large guests the spinning will be noticeable. >>>> I believe. >>>> >>>> >>> For interrupts going through IOPIC, but we know this is not scalable >>> anyway. >>> >>> >> Yes. We also wanted to convert the ioapic/pic to spinlocks so we could >> queue the interrupt from the PIT directly instead of using >> KVM_REQ_PENDING_TIMER which keeps confusing me. Chris Lalancette posted >> a patchset for this a while back but it was never completed. >> > Yeah, I'm sorry I never completed it. It turns out that with the HPET > changes that went in around the time I was looking at it, that set of > patches wasn't really required to fix the problem I was seeing with kdump. > > That being said, if it's useful to somebody, I can repost the patches > (though they are woefully out-of-date now). Let me know if you want > to see them again. > Let's see if one of the alternatives works out. I prefer to keep the critical sections short. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.