From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [Xen-devel] Re: [patch 14/21] Xen-paravirt: Add XEN config options and disableunsupported config options. Date: Fri, 16 Feb 2007 19:00:39 +0000 Message-ID: References: <45D5EDDB.7050404@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45D5EDDB.7050404@goop.org> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Fitzhardinge , Keir Fraser Cc: xen-devel@lists.xensource.com, Andi Kleen , linux-kernel@vger.kernel.org, Ian Pratt , Chris Wright , virtualization@lists.osdl.org, Andrew Morton , Steven Hand , Christian Limpach List-Id: virtualization@lists.linuxfoundation.org On 16/2/07 17:46, "Jeremy Fitzhardinge" wrote: > Keir Fraser wrote: >> This initial patchset does not include save/restore support anyway, so in >> fact it would be consistent to have CONFIG_PREEMPT configurable. I'm sure >> that we are going to have some nasty bugs to fix up as a result, but we >> can't fix them until we find them! Then we can convert our save/restore code >> to use the freezer before submitting it for inclusion. > OK. So that makes the only config restriction the 100Hz ticks. We can extend the Xen timer interface quite easily and get rid of this one too. In fact it doesn't *much* matter if the CONFIG_HZ differs from the Xen ticker rate -- we modified the Linux timer ISR to handle timer interrupts at arbitrary times already. The only drawback is that jiffies updates in burts if CONFIG_HZ is higher than the actual tick rate, and this can affect some calibration constants and cause Linux to print out some weird values at start-of-day. -- Keir