On Tue, Jan 17, 2012 at 10:27:26AM +0100, Alexander Graf wrote: > The thing I was getting at was not the map during the lifetime, but > the map during registration. Currently we have: > > 1) Set VPA to x > 2) Assign feature y to VPA > 3) Use VPA > > 1 and 2 are the slow path, 3 occurs more frequently. So we want 3 to > be fast. 1 and 2 don't matter that much wrt performance. > > You are currently mapping the VPA at /, which gets you into this > map/unmap mess trying to free the previous mapping. If you moved the > map to step 2 and only stored the GPA at step 1, all map+unmap > operations except for final unmaps would be in one spot, so you > wouldn't need to construct this big complex state machine. That might simplify things - I'll try it and see. The worry with doing the map/pin at 2 is that if anything goes wrong we no longer have the opportunity to return an error for the H_REGISTER_VPA call, so I'll have to at least do some checking in 1, leading to possibly more code overall. Paul. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
