From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric B Munson Subject: Re: [PATCH 0/4 V13] Avoid soft lockup message when KVM is stopped by host Date: Mon, 05 Mar 2012 09:10:02 -0800 Message-ID: <5f5cd9a500911093c5c585c9e78e8362@mgebm.net> References: <1328713666-11424-1-git-send-email-emunson@mgebm.net> <20120214152931.GA6881@mgebm.net> <20120214153836.GA21106@amt.cnet> <20120214155013.GB6881@mgebm.net> <20120214161009.GA21515@amt.cnet> <20120214211720.GC6881@mgebm.net> <20120305163943.GA10338@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120305163943.GA10338@amt.cnet> Sender: linux-kernel-owner@vger.kernel.org To: Marcelo Tosatti Cc: avi@redhat.com, mingo@redhat.com, hpa@zytor.com, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org List-Id: linux-arch.vger.kernel.org On Mon, 5 Mar 2012 13:39:43 -0300, Marcelo Tosatti wrote: > On Tue, Feb 14, 2012 at 04:17:20PM -0500, Eric B Munson wrote: >> On Tue, 14 Feb 2012, Marcelo Tosatti wrote: >> >> > On Tue, Feb 14, 2012 at 10:50:13AM -0500, Eric B Munson wrote: >> > > On Tue, 14 Feb 2012, Marcelo Tosatti wrote: >> > > >> > > > On Tue, Feb 14, 2012 at 10:29:31AM -0500, Eric B Munson wrote: >> > > > > On Wed, 08 Feb 2012, Eric B Munson wrote: >> > > > > >> > > > > > >> > > > > > When a guest kernel is stopped by the host hypervisor it >> can look like a soft >> > > > > > lockup to the guest kernel. This false warning can mask >> later soft lockup >> > > > > > warnings which may be real. This patch series adds a >> method for a host >> > > > > > hypervisor to communicate to a guest kernel that it is >> being stopped. The >> > > > > > final patch in the series has the watchdog check this flag >> when it goes to >> > > > > > issue a soft lockup warning and skip the warning if the >> guest knows it was >> > > > > > stopped. >> > > > > > >> > > > > > It was attempted to solve this in Qemu, but the side >> effects of saving and >> > > > > > restoring the clock and tsc for each vcpu put the wall >> clock of the guest behind >> > > > > > by the amount of time of the pause. This forces a guest >> to have ntp running >> > > > > > in order to keep the wall clock accurate. >> > > > > >> > > > > Avi, >> > > > > >> > > > > Is this set fit for merging or is there something else you >> want changed? >> > > > >> > > > Eric, >> > > > >> > > > On Message-ID: <20120210160536.GA23363@amt.cnet>, i asked: >> > > > >> > > > How is the stub getting included for other architectures >> again? >> > > > >> > > >> > > Marcelo, >> > > >> > > Sorry, I put out V13 to answer that. There is a stub in >> asm-generic that was >> > > lost in the V11-V12 rebase. This stub has be included in the >> V13 set. >> > > >> > > Eric >> > >> > Eric, >> > >> > I know the stub has been included in the series. But i am asking >> how >> > it is #include'ed for other architectures? (can't see that). >> >> Marcelo, >> >> kernel/watchdog.c now includes linux/kvm_para.h which includes >> asm/kvm_para.h. >> The check_and_clear function is defined in arch >> include/asm/kvm_para.h or in >> asm-generic/kvm_para.h for any arch lacking the specific header in >> their asm >> include dir. If I have misunderstood how these headers work, please >> let me >> know and I will fix it. > > There is no automatic inclusion of asm-generic/ headers. You must > create > kvm_para.h in each architecture's include/asm/ directory, #including > asm-generic/kvm_para.h. Okay, that will go into V16 then... Eric From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from oz.csail.mit.edu ([128.30.30.239]:56242 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756766Ab2CERK3 (ORCPT ); Mon, 5 Mar 2012 12:10:29 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 05 Mar 2012 09:10:02 -0800 From: Eric B Munson Subject: Re: [PATCH 0/4 V13] Avoid soft lockup message when KVM is stopped by host In-Reply-To: <20120305163943.GA10338@amt.cnet> References: <1328713666-11424-1-git-send-email-emunson@mgebm.net> <20120214152931.GA6881@mgebm.net> <20120214153836.GA21106@amt.cnet> <20120214155013.GB6881@mgebm.net> <20120214161009.GA21515@amt.cnet> <20120214211720.GC6881@mgebm.net> <20120305163943.GA10338@amt.cnet> Message-ID: <5f5cd9a500911093c5c585c9e78e8362@mgebm.net> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Marcelo Tosatti Cc: avi@redhat.com, mingo@redhat.com, hpa@zytor.com, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Message-ID: <20120305171002.pXdF_7LL3XYsfEdbdspyHDpwOBJSHfy4NSPe7oAAFbY@z> On Mon, 5 Mar 2012 13:39:43 -0300, Marcelo Tosatti wrote: > On Tue, Feb 14, 2012 at 04:17:20PM -0500, Eric B Munson wrote: >> On Tue, 14 Feb 2012, Marcelo Tosatti wrote: >> >> > On Tue, Feb 14, 2012 at 10:50:13AM -0500, Eric B Munson wrote: >> > > On Tue, 14 Feb 2012, Marcelo Tosatti wrote: >> > > >> > > > On Tue, Feb 14, 2012 at 10:29:31AM -0500, Eric B Munson wrote: >> > > > > On Wed, 08 Feb 2012, Eric B Munson wrote: >> > > > > >> > > > > > >> > > > > > When a guest kernel is stopped by the host hypervisor it >> can look like a soft >> > > > > > lockup to the guest kernel. This false warning can mask >> later soft lockup >> > > > > > warnings which may be real. This patch series adds a >> method for a host >> > > > > > hypervisor to communicate to a guest kernel that it is >> being stopped. The >> > > > > > final patch in the series has the watchdog check this flag >> when it goes to >> > > > > > issue a soft lockup warning and skip the warning if the >> guest knows it was >> > > > > > stopped. >> > > > > > >> > > > > > It was attempted to solve this in Qemu, but the side >> effects of saving and >> > > > > > restoring the clock and tsc for each vcpu put the wall >> clock of the guest behind >> > > > > > by the amount of time of the pause. This forces a guest >> to have ntp running >> > > > > > in order to keep the wall clock accurate. >> > > > > >> > > > > Avi, >> > > > > >> > > > > Is this set fit for merging or is there something else you >> want changed? >> > > > >> > > > Eric, >> > > > >> > > > On Message-ID: <20120210160536.GA23363@amt.cnet>, i asked: >> > > > >> > > > How is the stub getting included for other architectures >> again? >> > > > >> > > >> > > Marcelo, >> > > >> > > Sorry, I put out V13 to answer that. There is a stub in >> asm-generic that was >> > > lost in the V11-V12 rebase. This stub has be included in the >> V13 set. >> > > >> > > Eric >> > >> > Eric, >> > >> > I know the stub has been included in the series. But i am asking >> how >> > it is #include'ed for other architectures? (can't see that). >> >> Marcelo, >> >> kernel/watchdog.c now includes linux/kvm_para.h which includes >> asm/kvm_para.h. >> The check_and_clear function is defined in arch >> include/asm/kvm_para.h or in >> asm-generic/kvm_para.h for any arch lacking the specific header in >> their asm >> include dir. If I have misunderstood how these headers work, please >> let me >> know and I will fix it. > > There is no automatic inclusion of asm-generic/ headers. You must > create > kvm_para.h in each architecture's include/asm/ directory, #including > asm-generic/kvm_para.h. Okay, that will go into V16 then... Eric