From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ky Srinivasan" Subject: Re: context switch Date: Tue, 28 Mar 2006 19:49:22 -0500 Message-ID: <44299342.E57C.0030.0@novell.com> References: <44284B8E.E57C.0030.0@novell.com> <44291E76.E57C.0030.0@novell.com> <44292D32.E57C.0030.0@novell.com> <094de57bd0b22d011e9ecef9b84677a8@cl.cam.ac.uk> <8faa95f64ad61af657bdda6b115b5fd4@cl.cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <8faa95f64ad61af657bdda6b115b5fd4@cl.cam.ac.uk> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Kier, What are your thoughts on having a mechanism to manage hypervisor preemption from guest kernels? Regards, K. Y >>> On Tue, Mar 28, 2006 at 3:56 pm, in message <8faa95f64ad61af657bdda6b115b5fd4@cl.cam.ac.uk>, Keir Fraser wrote: > On 28 Mar 2006, at 20:35, Keir Fraser wrote: > >> We should probably just rely on the failsafe_handler actually >> (assuming it now works :- ) ). >> >> That 'slow path' will be taken so infrequently it's not worth having a >> special prepare_arch_switch() for Xen. It's really a hangover from the >> initial port from i386. > > Actually, we do still need to be sure to save the segment values before > switching TLS/LDT, so I guess we do need most of prepare_arch_switch > even on x86/64. > > We can't do the work in switch_mm() since lazy tlb logic may cause it > to not be executed. And switch_to() is too late. > > -- Keir