From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 4/4] Modify KVM to update guest time accounting. Date: Mon, 20 Aug 2007 17:08:23 +0300 Message-ID: <46C9A057.6060303@qumranet.com> References: <46C993A6.3060001@bull.net> <46C999C8.4080307@qumranet.com> <46C99C05.90701@bull.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , linux-kernel , virtualization To: Laurent Vivier Return-path: In-Reply-To: <46C99C05.90701-6ktuUTfB/bM@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Laurent Vivier wrote: > Avi Kivity wrote: > >> Laurent Vivier wrote: >> >>> [PATCH 4/4] Modify KVM to update guest time accounting. >>> >>> >>> >>> Index: kvm/drivers/kvm/kvm.h >>> =================================================================== >>> --- kvm.orig/drivers/kvm/kvm.h 2007-08-20 13:23:53.000000000 +0200 >>> +++ kvm/drivers/kvm/kvm.h 2007-08-20 13:23:58.000000000 +0200 >>> @@ -589,6 +589,17 @@ void kvm_mmu_unload(struct kvm_vcpu *vcp >>> >>> int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run); >>> >>> +static inline void kvm_guest_enter(void) >>> +{ >>> +#ifdef CONFIG_GUEST_ACCOUNTING >>> + current->flags |= PF_VCPU; >>> +#endif >>> >>> >> Since you select GUEST_ACCOUNTING, the #ifdef is always true? >> > > It is just to avoid error if we compile kvm module outside of the kernel, with > kernel without support of guest accounting. Can be removed if you want. > > Ah okay. We take care of the external module in external-module-compat.h (in this case, we can #define PF_VCPU to 0 if it is undefined). >>> +} >>> + >>> +static inline void kvm_guest_exit(void) >>> +{ >>> >>> >> Missing content? >> > > No, empty function. > > It is just to introduce "symmetry" in code, the VCPU code begins with > "kvm_guest_start()" and ends with "kvm_guest_exit()". And we have no operation > to do in kvm_guest_exit() (the PF_VCPU is cleared by account_system_time()), so > "empty function", removed by the optimizer (I hope). > But what if account_system_time() is not called (because we exited before the timer interrupt hit)? -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/