From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrea Arcangeli Subject: Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges Date: Fri, 29 Feb 2008 21:17:44 +0100 Message-ID: <20080229201744.GB8091@v2.random> References: <20080228001104.GB8091@v2.random> <20080228005249.GF8091@v2.random> <20080228011020.GG8091@v2.random> <20080229005530.GO8091@v2.random> <20080229131302.GT8091@v2.random> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Nick Piggin , steiner@sgi.com, Peter Zijlstra , linux-mm@kvack.org, Kanoj Sarcar , Roland Dreier , Steve Wise , linux-kernel@vger.kernel.org, Avi Kivity , kvm-devel@lists.sourceforge.net, daniel.blueman@quadrics.com, Robin Holt , general@lists.openfabrics.org, akpm@linux-foundation.org To: Christoph Lameter Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org On Fri, Feb 29, 2008 at 11:55:17AM -0800, Christoph Lameter wrote: > > post the invalidate in the mmio region of the device > > smp_call_function() > > while (mmio device wait-bitflag is on); > > So the device driver on UP can only operate through interrupts? If you are > hogging the only cpu then driver operations may not be possible. There was no irq involved in the above pseudocode, the irq if something would run in the remote system. Still irqs can run fine during the while loop like they run fine on top of smp_call_function. The send-irq and the following spin-on-a-bitflag works exactly as smp_call_function except this isn't a numa-CPU to invalidate. > And yes I would like to get rid of the mmu_rmap_notifiers altogether. It > would be much cleaner with just one mmu_notifier that can sleep in all > functions. Agreed. I just thought xpmem needed an invalidate-by-page, but I'm glad if xpmem can go in sync with the KVM/GRU/DRI model in this regard. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/