From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [PATCH 1/3] include files for kvmclock Date: Fri, 09 Nov 2007 09:37:30 +0100 Message-ID: <47341C4A.30508@redhat.com> References: <11945615632624-git-send-email-gcosta@redhat.com> <11945615703593-git-send-email-gcosta@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: jeremy-TSDbQ3PG+2Y@public.gmane.org, hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org, kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org To: Glauber de Oliveira Costa Return-path: In-Reply-To: <11945615703593-git-send-email-gcosta-H+wXaHxf7aLQT0dZR+AlfA@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 > +/* > + * Guest has page alignment and padding requirements. At the host, it will > + * only lead to wasted space at the vcpu struct. For this reason, the struct > + * is not anonymous > + */ > +union kvm_hv_clock { > + struct kvm_hv_clock_s { > + u64 tsc_mult; > + u64 now_ns; > + /* That's the wall clock, not the water closet */ > + u64 wc_sec; > + u64 last_tsc; > + /* At first, we could use the tsc value as a marker, but Jeremy > + * well noted that it will cause us locking problems in 32-bit > + * sys, so we have a special version field */ > + u32 version; > + } fields; > + char page_align[PAGE_SIZE]; > +}; What is the point in using a whole page per vcpu? You probably don't want struct kvm_hv_clock_s cross a page border. Is that the only reason or are there other constrains too? As the kvm clock looks quite simliar to what xen does, how about making the structs binary-compatible or simply reuse the xen version (struct vcpu_time_info in xen/interface/xen.h)? cheers, Gerd ------------------------------------------------------------------------- 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/