From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH v2] KVM: x86: Remove support for reporting coalesced APIC IRQs Date: Tue, 14 May 2013 12:10:17 +0300 Message-ID: <20130514091017.GC20995@redhat.com> References: <517D0784.7040400@web.de> <20130428114329.GK30504@redhat.com> <517D0F69.5080902@web.de> <20130503011432.GB5467@amt.cnet> <20130514013033.GA32410@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kiszka , kvm To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:12489 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756433Ab3ENJKT (ORCPT ); Tue, 14 May 2013 05:10:19 -0400 Content-Disposition: inline In-Reply-To: <20130514013033.GA32410@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, May 13, 2013 at 10:30:33PM -0300, Marcelo Tosatti wrote: > On Thu, May 02, 2013 at 10:14:32PM -0300, Marcelo Tosatti wrote: > > On Sun, Apr 28, 2013 at 02:00:41PM +0200, Jan Kiszka wrote: > > > From: Jan Kiszka > > > > > > Since the arrival of posted interrupt support we can no longer guarantee > > > that coalesced IRQs are always reported to the IRQ source. Moreover, > > > accumulated APIC timer events could cause a busy loop when a VCPU should > > > rather be halted. The consensus is to remove coalesced tracking from the > > > LAPIC. > > > > > > Signed-off-by: Jan Kiszka > > > --- > > > > > > Changes in v2: > > > - preserve return values where we need to count to how many VCPUs an > > > IRQ was delivered > > > > It would be best to confirm first that no guest depends on LAPIC timer > > reinjection (rather than wait for guests to break and spend time > > debugging). Specially since such kind of bugs are not easy to pinpoint. > > Or if there is evidence to invalidate such reasoning, please point it > > out. > > > > Honestly i don't recall: would have to check RHEL5.32 UP/SMP, RHEL5.64 > > UP/SMP, RHEL4.32, RHEL4.64, RHEL6. Can do that in a week or so. > > Its OK to remove LAPIC timer reinjection. Applied. Thanks for checking! -- Gleb.